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Does Bupropion and Metergoline interact?

•Drug A: Bupropion •Drug B: Metergoline •Severity: MODERATE •Description: The risk or severity of CNS depression can be increased when Bupropion is combined with Metergoline. •Extended Description: Central nervous system (CNS) depressants can cause sedation, falls, respiratory depression, coma, and death.2,3 The potential interaction between a CNS depressant and another CNS depressant drug due to synergistic effects is well documented in the literature, although the risk and severity of CNS depression vary from each drug. The subject and affected drugs are both CNS depressants that, when co-administered, may result in a more profound CNS depression. As the risk and severity of CNS depression resulting from the combined use of CNS depressants vary from each agent, each interaction between CNS depressants should be considered individually. •Indication (Drug A): Bupropion is indicated for the treatment of major depressive disorder (MDD), seasonal affective disorder (SAD), and as an aid to smoking cessation. When used in combination with naltrexone as the marketed product ContraveⓇ, bupropion is indicated as an adjunct to a reduced-calorie diet and increased physical activity for chronic weight management in adults with an initial body mass index (BMI) of: 30 kg/m^2 or greater (obese) or 27 kg/m^2 or greater (overweight) in the presence of at least one weight-related comorbid condition (e.g., hypertension, type 2 diabetes mellitus, or dyslipidemia). Bupropion is also used off-label as a first-line treatment in patients with ADHD and comorbid bipolar disorder when used as an adjunct to mood stabilizers. •Indication (Drug B): No indication available •Pharmacodynamics (Drug A): Bupropion is chemically unrelated to tricyclic, tetracyclic, selective serotonin re-uptake inhibitors, or other known antidepressant agents. Compared to classical tricyclic antidepressants, Bupropion is a relatively weak inhibitor of the neuronal uptake of norepinephrine and dopamine. In addition, Bupropion does not inhibit monoamine oxidase. Bupropion has been found to be essentially inactive at the serotonin transporter (SERT)(IC50 >10 000 nM), however both bupropion and its primary metabolite hydroxybupropion have been found to block the function of cation-selective serotonin type 3A receptors (5-HT3ARs). Bupropion produces dose-related central nervous system (CNS) stimulant effects in animals, as evidenced by increased locomotor activity, increased rates of responding in various schedule-controlled operant behaviour tasks, and, at high doses, induction of mild stereotyped behaviour. Due to these stimulant effects and selective activity at dopamine and norepinephrine receptors, bupropion has been identified as having an abuse potential. Bupropion has a similar structure to the controlled substance Cathinone, and has been identified as having mild amphetamine-like activity, particularly when inhaled or injected. Bupropion is also known to lower the seizure threshold, making any pre-existing seizure conditions a contraindication to its use. This risk is exacerbated when bupropion is combined with other drugs or substances that lower the seizure threshold, such as cocaine, or in clinical situations that would increase the risk of a seizure such as abrupt alcohol or benzodiazepine withdrawal. As norepinephrine has been shown to have anticonvulsant properties, bupropion's inhibitory effects on NET are thought to contribute to its pro-convulsant activity. Bupropion has been shown to increase blood pressure and pose a risk for exacerbation of unmanaged or pre-existing hypertension, however, clinical trials of bupropion in smokers with CVD have not identified an increased incidence of CV events including stroke or heart attack. In clinical trials, the mean increase in systolic blood pressure associated with the use of bupropion was found to be 1.3 mmHg. •Pharmacodynamics (Drug B): No pharmacodynamics available •Mechanism of action (Drug A): Bupropion is a norepinephrine/dopamine-reuptake inhibitor (NDRI) that exerts its pharmacological effects by weakly inhibiting the enzymes involved in the uptake of the neurotransmitters norepinephrine and dopamine from the synaptic cleft, therefore prolonging their duration of action within the neuronal synapse and the downstream effects of these neurotransmitters. More specifically, bupropion binds to the norepinephrine transporter (NET) and the dopamine transporter (DAT). Bupropion was originally classified as an "atypical" antidepressant because it does not exert the same effects as the classical antidepressants such as Monoamine Oxidase Inhibitors (MAOIs), Tricyclic Antidepressants (TCAs), or Selective Serotonin Reuptake Inhibitors (SSRIs). While it has comparable effectiveness to typical first-line options for the treatment of depression such as SSRIs, bupropion is a unique option for the treatment of MDD as it lacks any clinically relevant serotonergic effects, typical of other mood medications, or any effects on histamine or adrenaline receptors. Lack of activity at these receptors results in a more tolerable side effect profile; bupropion is less likely to cause sexual side effects, sedation, or weight gain as compared to SSRIs or TCAs, for example. When used as an aid to smoking cessation, bupropion is thought to confer its anti-craving and anti-withdrawal effects by inhibiting dopamine reuptake, which is thought to be involved in the reward pathways associated with nicotine, and through the antagonism of the nicotinic acetylcholinergic receptor (AChR), thereby blunting the effects of nicotine. Furthermore, the stimulatory effects produced by bupropion in the central nervous system are similar to nicotine's effects, making low doses of bupropion a suitable option as a nicotine substitute. When used in combination with naltrexone in the marketed product ContraveⓇ for chronic weight management, the two components are thought to have effects on areas of the brain involved in the regulation of food intake. This includes the hypothalamus, which is involved in appetite regulation, and the mesolimbic dopamine circuit, which is involved in reward pathways. Studies have shown that the combined activity of bupropion and naltrexone increase the firing rate of hypothalamic pro-opiomelanocortin (POMC) neurons and blockade of opioid receptor-mediated POMC auto-inhibition, which are associated with a reduction in food intake and increased energy expenditure. This combination was also found to reduce food intake when injected directly into the ventral tegmental area of the mesolimbic circuit in mice, which is an area associated with the regulation of reward pathways. •Mechanism of action (Drug B): No mechanism of action available •Absorption (Drug A): Bupropion is currently available in 3 distinct, but bioequivalent formulations: immediate release (IR), sustained-release (SR), and extended-release (XL). Immediate Release Formulation In humans, following oral administration of bupropion hydrochloride tablets, peak plasma bupropion concentrations are usually achieved within 2 hours. IR formulations provide a short duration of action and are therefore generally dosed three times per day. Sustained Release Formulation In humans, following oral administration of bupropion hydrochloride sustained-release tablets (SR), peak plasma concentration (Cmax) of bupropion is usually achieved within 3 hours. SR formulations provide a 12-hour extended release of medication and are therefore generally dosed twice per day. Extended Release Formulation Following single oral administration of bupropion hydrochloride extended-release tablets (XL) to healthy volunteers, the median time to peak plasma concentrations for bupropion was approximately 5 hours. The presence of food did not affect the peak concentration or area under the curve of bupropion. XL formulations provide a 24-hour extended release of medication and are therefore generally dosed once per day/ In a trial comparing chronic dosing with bupropion hydrochloride extended-release tablets (SR) 150 mg twice daily to bupropion immediate-release formulation 100 mg 3 times daily, the steady state Cmax for bupropion after bupropion hydrochloride sustained-release tablets (SR) administration was approximately 85% of those achieved after bupropion immediate-release formulation administration. Exposure (AUC) to bupropion was equivalent for both formulations. Bioequivalence was also demonstrated for all three major active metabolites (i.e., hydroxybupropion, threohydrobupropion and erythrohydrobupropion) for both Cmax and AUC. Thus, at steady state, bupropion hydrochloride sustained-release tablets (SR) given twice daily, and the immediate-release formulation of bupropion given 3 times daily, are essentially bioequivalent for both bupropion and the 3 quantitatively important metabolites. Furthermore, in a study comparing 14-day dosing with bupropion hydrochloride extended-release tablets (XL), 300 mg once-daily to the immediate-release formulation of bupropion at 100 mg 3 times daily, equivalence was demonstrated for peak plasma concentration and area under the curve for bupropion and the three metabolites (hydroxybupropion, threohydrobupropion, and erythrohydrobupropion). Additionally, in a study comparing 14-day dosing with bupropion hydrochloride extended-release tablets (XL) 300 mg once daily to the sustained-release formulation of bupropion at 150 mg 2 times daily, equivalence was demonstrated for peak plasma concentration and area under the curve for bupropion and the three metabolites. Bupropion hydrochloride extended-release tablets (SR) can be taken with or without food. Bupropion Cmax and AUC were increased by 11% to 35% and 16% to 19%, respectively, when bupropion hydrochloride extended-release tablets (SR) was administered with food to healthy volunteers in three trials. The food effect is not considered clinically significant. Following a single-dose administration of bupropion hydrochloride extended-release tablets (SR) in humans, Cmax of bupropion's metabolite hydroxybupropion occurs approximately 6 hours post-dose and is approximately 10 times the peak level of the parent drug at steady state. The elimination half-life of hydroxybupropion is approximately 20 (±5) hours and its AUC at steady state is about 17 times that of bupropion. The times to peak concentrations for the erythrohydrobupropion and threohydrobupropion metabolites are similar to that of the hydroxybupropion metabolite. However, their elimination half-lives are longer, 33(±10) and 37 (±13) hours, respectively, and steady-state AUCs are 1.5 and 7 times that of bupropion, respectively. •Absorption (Drug B): No absorption available •Volume of distribution (Drug A): No volume of distribution available •Volume of distribution (Drug B): No volume of distribution available •Protein binding (Drug A): In vitro tests show that bupropion is 84% bound to human plasma proteins at concentrations up to 200 mcg per mL. The extent of protein binding of the hydroxybupropion metabolite is similar to that for bupropion, whereas the extent of protein binding of the threohydrobupropion metabolite is about half that seen with bupropion. •Protein binding (Drug B): No protein binding available •Metabolism (Drug A): Bupropion is extensively metabolized in humans. Three metabolites are active: hydroxybupropion, which is formed via hydroxylation of the tert-butyl group of bupropion, and the amino-alcohol isomers, threohydrobupropion and erythrohydrobupropion, which are formed via reduction of the carbonyl group. In vitro findings suggest that CYP2B6 is the principal isoenzyme involved in the formation of hydroxybupropion, while cytochrome P450 enzymes are not involved in the formation of threohydrobupropion. Hydroxybupropion has been shown to have the same affinity as bupropion for the norepinephrine transporter (NET) but approximately 50% of its antidepressant activity despite reaching concentrations of ~10-fold higher than that of the parent drug. Oxidation of the bupropion side chain results in the formation of a glycine conjugate of meta-chlorobenzoic acid, which is then excreted as the major urinary metabolite. The potency and toxicity of the metabolites relative to bupropion have not been fully characterized. However, it has been demonstrated in an antidepressant screening test in mice that hydroxybupropion is one-half as potent as bupropion, while threohydrobupropion and erythrohydrobupropion are 5-fold less potent than bupropion. This may be of clinical importance because the plasma concentrations of the metabolites are as high as or higher than those of bupropion. Bupropion and its metabolites exhibit linear kinetics following chronic administration of 300 to 450 mg per day. •Metabolism (Drug B): No metabolism available •Route of elimination (Drug A): Bupropion is extensively metabolized in humans. Oxidation of the bupropion side chain results in the formation of a glycine conjugate of metachlorobenzoic acid, which is then excreted as the major urinary metabolite. Following oral administration of 200 mg of 14C-bupropion in humans, 87% and 10% of the radioactive dose were recovered in the urine and feces, respectively. However, the fraction of the oral dose of bupropion excreted unchanged was only 0.5%, a finding consistent with the extensive metabolism of bupropion. •Route of elimination (Drug B): No route of elimination available •Half-life (Drug A): 24 hours •Half-life (Drug B): No half-life available •Clearance (Drug A): No clearance available •Clearance (Drug B): No clearance available •Toxicity (Drug A): Symptoms of overdose include seizures, hallucinations, loss of consciousness, tachycardia, and cardiac arrest. •Toxicity (Drug B): No toxicity available •Brand Names (Drug A): Aplenzin, Auvelity, Budeprion, Contrave, Forfivo, Wellbutrin, Zyban •Brand Names (Drug B): No brand names available •Synonyms (Drug A): No synonyms listed •Synonyms (Drug B): No synonyms listed •Summary (Drug A): Bupropion is a norepinephrine and dopamine reuptake inhibitor used in the treatment of major depressive disorder (MDD), seasonal affective disorder (SAD), and as an aid to smoking cessation. •Summary (Drug B): Metergoline is an ergot-derivative that acts as an antagonist at certain 5-HT receptor subtypes and as an agonist at dopamine receptors. It is often used in situations where inhibition of prolactin is desirable.

Central nervous system (CNS) depressants can cause sedation, falls, respiratory depression, coma, and death.2,3 The potential interaction between a CNS depressant and another CNS depressant drug due to synergistic effects is well documented in the literature, although the risk and severity of CNS depression vary from each drug. The subject and affected drugs are both CNS depressants that, when co-administered, may result in a more profound CNS depression. As the risk and severity of CNS depression resulting from the combined use of CNS depressants vary from each agent, each interaction between CNS depressants should be considered individually. The severity of the interaction is moderate.

Question: Does Bupropion and Metergoline interact? Information: •Drug A: Bupropion •Drug B: Metergoline •Severity: MODERATE •Description: The risk or severity of CNS depression can be increased when Bupropion is combined with Metergoline. •Extended Description: Central nervous system (CNS) depressants can cause sedation, falls, respiratory depression, coma, and death.2,3 The potential interaction between a CNS depressant and another CNS depressant drug due to synergistic effects is well documented in the literature, although the risk and severity of CNS depression vary from each drug. The subject and affected drugs are both CNS depressants that, when co-administered, may result in a more profound CNS depression. As the risk and severity of CNS depression resulting from the combined use of CNS depressants vary from each agent, each interaction between CNS depressants should be considered individually. •Indication (Drug A): Bupropion is indicated for the treatment of major depressive disorder (MDD), seasonal affective disorder (SAD), and as an aid to smoking cessation. When used in combination with naltrexone as the marketed product ContraveⓇ, bupropion is indicated as an adjunct to a reduced-calorie diet and increased physical activity for chronic weight management in adults with an initial body mass index (BMI) of: 30 kg/m^2 or greater (obese) or 27 kg/m^2 or greater (overweight) in the presence of at least one weight-related comorbid condition (e.g., hypertension, type 2 diabetes mellitus, or dyslipidemia). Bupropion is also used off-label as a first-line treatment in patients with ADHD and comorbid bipolar disorder when used as an adjunct to mood stabilizers. •Indication (Drug B): No indication available •Pharmacodynamics (Drug A): Bupropion is chemically unrelated to tricyclic, tetracyclic, selective serotonin re-uptake inhibitors, or other known antidepressant agents. Compared to classical tricyclic antidepressants, Bupropion is a relatively weak inhibitor of the neuronal uptake of norepinephrine and dopamine. In addition, Bupropion does not inhibit monoamine oxidase. Bupropion has been found to be essentially inactive at the serotonin transporter (SERT)(IC50 >10 000 nM), however both bupropion and its primary metabolite hydroxybupropion have been found to block the function of cation-selective serotonin type 3A receptors (5-HT3ARs). Bupropion produces dose-related central nervous system (CNS) stimulant effects in animals, as evidenced by increased locomotor activity, increased rates of responding in various schedule-controlled operant behaviour tasks, and, at high doses, induction of mild stereotyped behaviour. Due to these stimulant effects and selective activity at dopamine and norepinephrine receptors, bupropion has been identified as having an abuse potential. Bupropion has a similar structure to the controlled substance Cathinone, and has been identified as having mild amphetamine-like activity, particularly when inhaled or injected. Bupropion is also known to lower the seizure threshold, making any pre-existing seizure conditions a contraindication to its use. This risk is exacerbated when bupropion is combined with other drugs or substances that lower the seizure threshold, such as cocaine, or in clinical situations that would increase the risk of a seizure such as abrupt alcohol or benzodiazepine withdrawal. As norepinephrine has been shown to have anticonvulsant properties, bupropion's inhibitory effects on NET are thought to contribute to its pro-convulsant activity. Bupropion has been shown to increase blood pressure and pose a risk for exacerbation of unmanaged or pre-existing hypertension, however, clinical trials of bupropion in smokers with CVD have not identified an increased incidence of CV events including stroke or heart attack. In clinical trials, the mean increase in systolic blood pressure associated with the use of bupropion was found to be 1.3 mmHg. •Pharmacodynamics (Drug B): No pharmacodynamics available •Mechanism of action (Drug A): Bupropion is a norepinephrine/dopamine-reuptake inhibitor (NDRI) that exerts its pharmacological effects by weakly inhibiting the enzymes involved in the uptake of the neurotransmitters norepinephrine and dopamine from the synaptic cleft, therefore prolonging their duration of action within the neuronal synapse and the downstream effects of these neurotransmitters. More specifically, bupropion binds to the norepinephrine transporter (NET) and the dopamine transporter (DAT). Bupropion was originally classified as an "atypical" antidepressant because it does not exert the same effects as the classical antidepressants such as Monoamine Oxidase Inhibitors (MAOIs), Tricyclic Antidepressants (TCAs), or Selective Serotonin Reuptake Inhibitors (SSRIs). While it has comparable effectiveness to typical first-line options for the treatment of depression such as SSRIs, bupropion is a unique option for the treatment of MDD as it lacks any clinically relevant serotonergic effects, typical of other mood medications, or any effects on histamine or adrenaline receptors. Lack of activity at these receptors results in a more tolerable side effect profile; bupropion is less likely to cause sexual side effects, sedation, or weight gain as compared to SSRIs or TCAs, for example. When used as an aid to smoking cessation, bupropion is thought to confer its anti-craving and anti-withdrawal effects by inhibiting dopamine reuptake, which is thought to be involved in the reward pathways associated with nicotine, and through the antagonism of the nicotinic acetylcholinergic receptor (AChR), thereby blunting the effects of nicotine. Furthermore, the stimulatory effects produced by bupropion in the central nervous system are similar to nicotine's effects, making low doses of bupropion a suitable option as a nicotine substitute. When used in combination with naltrexone in the marketed product ContraveⓇ for chronic weight management, the two components are thought to have effects on areas of the brain involved in the regulation of food intake. This includes the hypothalamus, which is involved in appetite regulation, and the mesolimbic dopamine circuit, which is involved in reward pathways. Studies have shown that the combined activity of bupropion and naltrexone increase the firing rate of hypothalamic pro-opiomelanocortin (POMC) neurons and blockade of opioid receptor-mediated POMC auto-inhibition, which are associated with a reduction in food intake and increased energy expenditure. This combination was also found to reduce food intake when injected directly into the ventral tegmental area of the mesolimbic circuit in mice, which is an area associated with the regulation of reward pathways. •Mechanism of action (Drug B): No mechanism of action available •Absorption (Drug A): Bupropion is currently available in 3 distinct, but bioequivalent formulations: immediate release (IR), sustained-release (SR), and extended-release (XL). Immediate Release Formulation In humans, following oral administration of bupropion hydrochloride tablets, peak plasma bupropion concentrations are usually achieved within 2 hours. IR formulations provide a short duration of action and are therefore generally dosed three times per day. Sustained Release Formulation In humans, following oral administration of bupropion hydrochloride sustained-release tablets (SR), peak plasma concentration (Cmax) of bupropion is usually achieved within 3 hours. SR formulations provide a 12-hour extended release of medication and are therefore generally dosed twice per day. Extended Release Formulation Following single oral administration of bupropion hydrochloride extended-release tablets (XL) to healthy volunteers, the median time to peak plasma concentrations for bupropion was approximately 5 hours. The presence of food did not affect the peak concentration or area under the curve of bupropion. XL formulations provide a 24-hour extended release of medication and are therefore generally dosed once per day/ In a trial comparing chronic dosing with bupropion hydrochloride extended-release tablets (SR) 150 mg twice daily to bupropion immediate-release formulation 100 mg 3 times daily, the steady state Cmax for bupropion after bupropion hydrochloride sustained-release tablets (SR) administration was approximately 85% of those achieved after bupropion immediate-release formulation administration. Exposure (AUC) to bupropion was equivalent for both formulations. Bioequivalence was also demonstrated for all three major active metabolites (i.e., hydroxybupropion, threohydrobupropion and erythrohydrobupropion) for both Cmax and AUC. Thus, at steady state, bupropion hydrochloride sustained-release tablets (SR) given twice daily, and the immediate-release formulation of bupropion given 3 times daily, are essentially bioequivalent for both bupropion and the 3 quantitatively important metabolites. Furthermore, in a study comparing 14-day dosing with bupropion hydrochloride extended-release tablets (XL), 300 mg once-daily to the immediate-release formulation of bupropion at 100 mg 3 times daily, equivalence was demonstrated for peak plasma concentration and area under the curve for bupropion and the three metabolites (hydroxybupropion, threohydrobupropion, and erythrohydrobupropion). Additionally, in a study comparing 14-day dosing with bupropion hydrochloride extended-release tablets (XL) 300 mg once daily to the sustained-release formulation of bupropion at 150 mg 2 times daily, equivalence was demonstrated for peak plasma concentration and area under the curve for bupropion and the three metabolites. Bupropion hydrochloride extended-release tablets (SR) can be taken with or without food. Bupropion Cmax and AUC were increased by 11% to 35% and 16% to 19%, respectively, when bupropion hydrochloride extended-release tablets (SR) was administered with food to healthy volunteers in three trials. The food effect is not considered clinically significant. Following a single-dose administration of bupropion hydrochloride extended-release tablets (SR) in humans, Cmax of bupropion's metabolite hydroxybupropion occurs approximately 6 hours post-dose and is approximately 10 times the peak level of the parent drug at steady state. The elimination half-life of hydroxybupropion is approximately 20 (±5) hours and its AUC at steady state is about 17 times that of bupropion. The times to peak concentrations for the erythrohydrobupropion and threohydrobupropion metabolites are similar to that of the hydroxybupropion metabolite. However, their elimination half-lives are longer, 33(±10) and 37 (±13) hours, respectively, and steady-state AUCs are 1.5 and 7 times that of bupropion, respectively. •Absorption (Drug B): No absorption available •Volume of distribution (Drug A): No volume of distribution available •Volume of distribution (Drug B): No volume of distribution available •Protein binding (Drug A): In vitro tests show that bupropion is 84% bound to human plasma proteins at concentrations up to 200 mcg per mL. The extent of protein binding of the hydroxybupropion metabolite is similar to that for bupropion, whereas the extent of protein binding of the threohydrobupropion metabolite is about half that seen with bupropion. •Protein binding (Drug B): No protein binding available •Metabolism (Drug A): Bupropion is extensively metabolized in humans. Three metabolites are active: hydroxybupropion, which is formed via hydroxylation of the tert-butyl group of bupropion, and the amino-alcohol isomers, threohydrobupropion and erythrohydrobupropion, which are formed via reduction of the carbonyl group. In vitro findings suggest that CYP2B6 is the principal isoenzyme involved in the formation of hydroxybupropion, while cytochrome P450 enzymes are not involved in the formation of threohydrobupropion. Hydroxybupropion has been shown to have the same affinity as bupropion for the norepinephrine transporter (NET) but approximately 50% of its antidepressant activity despite reaching concentrations of ~10-fold higher than that of the parent drug. Oxidation of the bupropion side chain results in the formation of a glycine conjugate of meta-chlorobenzoic acid, which is then excreted as the major urinary metabolite. The potency and toxicity of the metabolites relative to bupropion have not been fully characterized. However, it has been demonstrated in an antidepressant screening test in mice that hydroxybupropion is one-half as potent as bupropion, while threohydrobupropion and erythrohydrobupropion are 5-fold less potent than bupropion. This may be of clinical importance because the plasma concentrations of the metabolites are as high as or higher than those of bupropion. Bupropion and its metabolites exhibit linear kinetics following chronic administration of 300 to 450 mg per day. •Metabolism (Drug B): No metabolism available •Route of elimination (Drug A): Bupropion is extensively metabolized in humans. Oxidation of the bupropion side chain results in the formation of a glycine conjugate of metachlorobenzoic acid, which is then excreted as the major urinary metabolite. Following oral administration of 200 mg of 14C-bupropion in humans, 87% and 10% of the radioactive dose were recovered in the urine and feces, respectively. However, the fraction of the oral dose of bupropion excreted unchanged was only 0.5%, a finding consistent with the extensive metabolism of bupropion. •Route of elimination (Drug B): No route of elimination available •Half-life (Drug A): 24 hours •Half-life (Drug B): No half-life available •Clearance (Drug A): No clearance available •Clearance (Drug B): No clearance available •Toxicity (Drug A): Symptoms of overdose include seizures, hallucinations, loss of consciousness, tachycardia, and cardiac arrest. •Toxicity (Drug B): No toxicity available •Brand Names (Drug A): Aplenzin, Auvelity, Budeprion, Contrave, Forfivo, Wellbutrin, Zyban •Brand Names (Drug B): No brand names available •Synonyms (Drug A): No synonyms listed •Synonyms (Drug B): No synonyms listed •Summary (Drug A): Bupropion is a norepinephrine and dopamine reuptake inhibitor used in the treatment of major depressive disorder (MDD), seasonal affective disorder (SAD), and as an aid to smoking cessation. •Summary (Drug B): Metergoline is an ergot-derivative that acts as an antagonist at certain 5-HT receptor subtypes and as an agonist at dopamine receptors. It is often used in situations where inhibition of prolactin is desirable. Output: Central nervous system (CNS) depressants can cause sedation, falls, respiratory depression, coma, and death.2,3 The potential interaction between a CNS depressant and another CNS depressant drug due to synergistic effects is well documented in the literature, although the risk and severity of CNS depression vary from each drug. The subject and affected drugs are both CNS depressants that, when co-administered, may result in a more profound CNS depression. As the risk and severity of CNS depression resulting from the combined use of CNS depressants vary from each agent, each interaction between CNS depressants should be considered individually. The severity of the interaction is moderate.

Does Bupropion and Metformin interact?

•Drug A: Bupropion •Drug B: Metformin •Severity: MODERATE •Description: The excretion of Metformin can be decreased when combined with Bupropion. •Extended Description: Findings from in vitro studies showed that bupropion and its metabolites inhibit OCT2, suggesting that clinically relevant interaction through inhibition of OCT2 could occur at therapeutic bupropion doses. Co-administration of bupropion with OCT2 substrates may result in attenuated OCT2-mediated efflux of those drugs, thereby increasing drug serum concentrations. •Indication (Drug A): Bupropion is indicated for the treatment of major depressive disorder (MDD), seasonal affective disorder (SAD), and as an aid to smoking cessation. When used in combination with naltrexone as the marketed product ContraveⓇ, bupropion is indicated as an adjunct to a reduced-calorie diet and increased physical activity for chronic weight management in adults with an initial body mass index (BMI) of: 30 kg/m^2 or greater (obese) or 27 kg/m^2 or greater (overweight) in the presence of at least one weight-related comorbid condition (e.g., hypertension, type 2 diabetes mellitus, or dyslipidemia). Bupropion is also used off-label as a first-line treatment in patients with ADHD and comorbid bipolar disorder when used as an adjunct to mood stabilizers. •Indication (Drug B): Metformin immediate-release formulations Metformin is indicated as an adjunct to diet and exercise to improve glycemic control in adults and pediatric patients ≥10 years old with type 2 diabetes mellitus. Metformin extended-release tablet (XR) The extended-release formulation of metformin is indicated as an adjunct to diet and exercise to improve glycemic control in adults with type 2 diabetes mellitus. Safety in children has not been determined to this date. Metformin combination products Metformin is a component of a variety of combination products with other anti-diabetic agents. It is indicated, along with diet and exercise, to improve glycemic control in adult patients with type 2 diabetes mellitus in combination with DPP-4 inhibitors ( sitagliptin, linagliptin, alogliptin, or saxagliptin ), in combination with SGLT2 inhibitors ( canagliflozin, empagliflozin, ertugliflozin, or dapagliflozin ), or in combination with pioglitazone. •Pharmacodynamics (Drug A): Bupropion is chemically unrelated to tricyclic, tetracyclic, selective serotonin re-uptake inhibitors, or other known antidepressant agents. Compared to classical tricyclic antidepressants, Bupropion is a relatively weak inhibitor of the neuronal uptake of norepinephrine and dopamine. In addition, Bupropion does not inhibit monoamine oxidase. Bupropion has been found to be essentially inactive at the serotonin transporter (SERT)(IC50 >10 000 nM), however both bupropion and its primary metabolite hydroxybupropion have been found to block the function of cation-selective serotonin type 3A receptors (5-HT3ARs). Bupropion produces dose-related central nervous system (CNS) stimulant effects in animals, as evidenced by increased locomotor activity, increased rates of responding in various schedule-controlled operant behaviour tasks, and, at high doses, induction of mild stereotyped behaviour. Due to these stimulant effects and selective activity at dopamine and norepinephrine receptors, bupropion has been identified as having an abuse potential. Bupropion has a similar structure to the controlled substance Cathinone, and has been identified as having mild amphetamine-like activity, particularly when inhaled or injected. Bupropion is also known to lower the seizure threshold, making any pre-existing seizure conditions a contraindication to its use. This risk is exacerbated when bupropion is combined with other drugs or substances that lower the seizure threshold, such as cocaine, or in clinical situations that would increase the risk of a seizure such as abrupt alcohol or benzodiazepine withdrawal. As norepinephrine has been shown to have anticonvulsant properties, bupropion's inhibitory effects on NET are thought to contribute to its pro-convulsant activity. Bupropion has been shown to increase blood pressure and pose a risk for exacerbation of unmanaged or pre-existing hypertension, however, clinical trials of bupropion in smokers with CVD have not identified an increased incidence of CV events including stroke or heart attack. In clinical trials, the mean increase in systolic blood pressure associated with the use of bupropion was found to be 1.3 mmHg. •Pharmacodynamics (Drug B): General effects Insulin is an important hormone that regulates blood glucose levels. Type II diabetes is characterized by a decrease in sensitivity to insulin, resulting in elevations in blood glucose when the pancreas can no longer compensate. In patients diagnosed with type 2 diabetes, insulin is unable to exert adequate effects on tissues and cells (i.e. insulin resistance) and insulin deficiency may also be present. Metformin reduces hepatic production of glucose, decreases the intestinal absorption of glucose, and enhances insulin sensitivity by increasing both peripheral glucose uptake and utilization. In contrast with drugs of the sulfonylurea class, which lead to hyperinsulinemia, the secretion of insulin is unchanged with metformin use. Effect on fasting plasma glucose (FPG) and Glycosylated hemoglobin (HbA1c) HbA1c is an important periodic measure of glycemic control used to monitor diabetic patients. Fasting plasma glucose is also a useful and important measure of glycemic control. In a 29-week clinical trial of subjects diagnosed with type II diabetes, metformin decreased the fasting plasma glucose levels by an average of 59 mg/dL from baseline, compared to an average increase of 6.3 mg/dL from baseline in subjects taking a placebo. Glycosylated hemoglobin (HbA1c) was decreased by about 1.4% in subjects receiving metformin, and increased by 0.4% in subjects receiving placebo only. •Mechanism of action (Drug A): Bupropion is a norepinephrine/dopamine-reuptake inhibitor (NDRI) that exerts its pharmacological effects by weakly inhibiting the enzymes involved in the uptake of the neurotransmitters norepinephrine and dopamine from the synaptic cleft, therefore prolonging their duration of action within the neuronal synapse and the downstream effects of these neurotransmitters. More specifically, bupropion binds to the norepinephrine transporter (NET) and the dopamine transporter (DAT). Bupropion was originally classified as an "atypical" antidepressant because it does not exert the same effects as the classical antidepressants such as Monoamine Oxidase Inhibitors (MAOIs), Tricyclic Antidepressants (TCAs), or Selective Serotonin Reuptake Inhibitors (SSRIs). While it has comparable effectiveness to typical first-line options for the treatment of depression such as SSRIs, bupropion is a unique option for the treatment of MDD as it lacks any clinically relevant serotonergic effects, typical of other mood medications, or any effects on histamine or adrenaline receptors. Lack of activity at these receptors results in a more tolerable side effect profile; bupropion is less likely to cause sexual side effects, sedation, or weight gain as compared to SSRIs or TCAs, for example. When used as an aid to smoking cessation, bupropion is thought to confer its anti-craving and anti-withdrawal effects by inhibiting dopamine reuptake, which is thought to be involved in the reward pathways associated with nicotine, and through the antagonism of the nicotinic acetylcholinergic receptor (AChR), thereby blunting the effects of nicotine. Furthermore, the stimulatory effects produced by bupropion in the central nervous system are similar to nicotine's effects, making low doses of bupropion a suitable option as a nicotine substitute. When used in combination with naltrexone in the marketed product ContraveⓇ for chronic weight management, the two components are thought to have effects on areas of the brain involved in the regulation of food intake. This includes the hypothalamus, which is involved in appetite regulation, and the mesolimbic dopamine circuit, which is involved in reward pathways. Studies have shown that the combined activity of bupropion and naltrexone increase the firing rate of hypothalamic pro-opiomelanocortin (POMC) neurons and blockade of opioid receptor-mediated POMC auto-inhibition, which are associated with a reduction in food intake and increased energy expenditure. This combination was also found to reduce food intake when injected directly into the ventral tegmental area of the mesolimbic circuit in mice, which is an area associated with the regulation of reward pathways. •Mechanism of action (Drug B): Metformin's mechanisms of action are unique from other classes of oral antihyperglycemic drugs. Metformin decreases blood glucose levels by decreasing hepatic glucose production (also called gluconeogenesis), decreasing the intestinal absorption of glucose, and increasing insulin sensitivity by increasing peripheral glucose uptake and utilization. It is well established that metformin inhibits mitochondrial complex I activity, and it has since been generally postulated that its potent antidiabetic effects occur through this mechanism. The above processes lead to a decrease in blood glucose, managing type II diabetes and exerting positive effects on glycemic control. After ingestion, the organic cation transporter-1 (OCT1) is responsible for the uptake of metformin into hepatocytes (liver cells). As this drug is positively charged, it accumulates in cells and in the mitochondria because of the membrane potentials across the plasma membrane as well as the mitochondrial inner membrane. Metformin inhibits mitochondrial complex I, preventing the production of mitochondrial ATP leading to increased cytoplasmic ADP:ATP and AMP:ATP ratios. These changes activate AMP-activated protein kinase (AMPK), an enzyme that plays an important role in the regulation of glucose metabolism. Aside from this mechanism, AMPK can be activated by a lysosomal mechanism involving other activators. Following this process, increases in AMP:ATP ratio also inhibit fructose-1,6-bisphosphatase enzyme, resulting in the inhibition of gluconeogenesis, while also inhibiting adenylate cyclase and decreasing the production of cyclic adenosine monophosphate (cAMP), a derivative of ATP used for cell signaling. Activated AMPK phosphorylates two isoforms of acetyl-CoA carboxylase enzyme, thereby inhibiting fat synthesis and leading to fat oxidation, reducing hepatic lipid stores and increasing liver sensitivity to insulin. In the intestines, metformin increases anaerobic glucose metabolism in enterocytes (intestinal cells), leading to reduced net glucose uptake and increased delivery of lactate to the liver. Recent studies have also implicated the gut as a primary site of action of metformin and suggest that the liver may not be as important for metformin action in patients with type 2 diabetes. Some of the ways metformin may play a role on the intestines is by promoting the metabolism of glucose by increasing glucagon-like peptide I (GLP-1) as well as increasing gut utilization of glucose. In addition to the above pathway, the mechanism of action of metformin may be explained by other ways, and its exact mechanism of action has been under extensive study in recent years. •Absorption (Drug A): Bupropion is currently available in 3 distinct, but bioequivalent formulations: immediate release (IR), sustained-release (SR), and extended-release (XL). Immediate Release Formulation In humans, following oral administration of bupropion hydrochloride tablets, peak plasma bupropion concentrations are usually achieved within 2 hours. IR formulations provide a short duration of action and are therefore generally dosed three times per day. Sustained Release Formulation In humans, following oral administration of bupropion hydrochloride sustained-release tablets (SR), peak plasma concentration (Cmax) of bupropion is usually achieved within 3 hours. SR formulations provide a 12-hour extended release of medication and are therefore generally dosed twice per day. Extended Release Formulation Following single oral administration of bupropion hydrochloride extended-release tablets (XL) to healthy volunteers, the median time to peak plasma concentrations for bupropion was approximately 5 hours. The presence of food did not affect the peak concentration or area under the curve of bupropion. XL formulations provide a 24-hour extended release of medication and are therefore generally dosed once per day/ In a trial comparing chronic dosing with bupropion hydrochloride extended-release tablets (SR) 150 mg twice daily to bupropion immediate-release formulation 100 mg 3 times daily, the steady state Cmax for bupropion after bupropion hydrochloride sustained-release tablets (SR) administration was approximately 85% of those achieved after bupropion immediate-release formulation administration. Exposure (AUC) to bupropion was equivalent for both formulations. Bioequivalence was also demonstrated for all three major active metabolites (i.e., hydroxybupropion, threohydrobupropion and erythrohydrobupropion) for both Cmax and AUC. Thus, at steady state, bupropion hydrochloride sustained-release tablets (SR) given twice daily, and the immediate-release formulation of bupropion given 3 times daily, are essentially bioequivalent for both bupropion and the 3 quantitatively important metabolites. Furthermore, in a study comparing 14-day dosing with bupropion hydrochloride extended-release tablets (XL), 300 mg once-daily to the immediate-release formulation of bupropion at 100 mg 3 times daily, equivalence was demonstrated for peak plasma concentration and area under the curve for bupropion and the three metabolites (hydroxybupropion, threohydrobupropion, and erythrohydrobupropion). Additionally, in a study comparing 14-day dosing with bupropion hydrochloride extended-release tablets (XL) 300 mg once daily to the sustained-release formulation of bupropion at 150 mg 2 times daily, equivalence was demonstrated for peak plasma concentration and area under the curve for bupropion and the three metabolites. Bupropion hydrochloride extended-release tablets (SR) can be taken with or without food. Bupropion Cmax and AUC were increased by 11% to 35% and 16% to 19%, respectively, when bupropion hydrochloride extended-release tablets (SR) was administered with food to healthy volunteers in three trials. The food effect is not considered clinically significant. Following a single-dose administration of bupropion hydrochloride extended-release tablets (SR) in humans, Cmax of bupropion's metabolite hydroxybupropion occurs approximately 6 hours post-dose and is approximately 10 times the peak level of the parent drug at steady state. The elimination half-life of hydroxybupropion is approximately 20 (±5) hours and its AUC at steady state is about 17 times that of bupropion. The times to peak concentrations for the erythrohydrobupropion and threohydrobupropion metabolites are similar to that of the hydroxybupropion metabolite. However, their elimination half-lives are longer, 33(±10) and 37 (±13) hours, respectively, and steady-state AUCs are 1.5 and 7 times that of bupropion, respectively. •Absorption (Drug B): Regular tablet absorption The absolute bioavailability of a metformin 500 mg tablet administered in the fasting state is about 50%-60%. Single-dose clinical studies using oral doses of metformin 500 to 1500 mg and 850 to 2550 mg show that there is a lack of dose proportionality with an increase in metformin dose, attributed to decreased absorption rather than changes in elimination. At usual clinical doses and dosing schedules of metformin, steady-state plasma concentrations of metformin are achieved within 24-48 hours and are normally measured at <1 μg/mL. Extended-release tablet absorption After a single oral dose of metformin extended-release, Cmax is reached with a median value of 7 hours and a range of between 4 and 8 hours. Peak plasma levels are measured to be about 20% lower compared to the same dose of regular metformin, however, the extent of absorption of both forms (as measured by area under the curve - AUC), are similar. Effect of food Food reduces the absorption of metformin, as demonstrated by about a 40% lower mean peak plasma concentration (Cmax), a 25% lower area under the plasma concentration versus time curve (AUC), and a 35-minute increase in time to peak plasma concentration (Tmax) after ingestion of an 850 mg tablet of metformin taken with food, compared to the same dose administered during fasting. Though the extent of metformin absorption (measured by the area under the curve - AUC) from the metformin extended-release tablet is increased by about 50% when given with food, no effect of food on Cmax and Tmax of metformin is observed. High and low-fat meals exert similar effects on the pharmacokinetics of extended-release metformin. •Volume of distribution (Drug A): No volume of distribution available •Volume of distribution (Drug B): The apparent volume of distribution (V/F) of metformin after one oral dose of metformin 850 mg averaged at 654 ± 358 L. •Protein binding (Drug A): In vitro tests show that bupropion is 84% bound to human plasma proteins at concentrations up to 200 mcg per mL. The extent of protein binding of the hydroxybupropion metabolite is similar to that for bupropion, whereas the extent of protein binding of the threohydrobupropion metabolite is about half that seen with bupropion. •Protein binding (Drug B): Metformin is negligibly bound to plasma proteins. •Metabolism (Drug A): Bupropion is extensively metabolized in humans. Three metabolites are active: hydroxybupropion, which is formed via hydroxylation of the tert-butyl group of bupropion, and the amino-alcohol isomers, threohydrobupropion and erythrohydrobupropion, which are formed via reduction of the carbonyl group. In vitro findings suggest that CYP2B6 is the principal isoenzyme involved in the formation of hydroxybupropion, while cytochrome P450 enzymes are not involved in the formation of threohydrobupropion. Hydroxybupropion has been shown to have the same affinity as bupropion for the norepinephrine transporter (NET) but approximately 50% of its antidepressant activity despite reaching concentrations of ~10-fold higher than that of the parent drug. Oxidation of the bupropion side chain results in the formation of a glycine conjugate of meta-chlorobenzoic acid, which is then excreted as the major urinary metabolite. The potency and toxicity of the metabolites relative to bupropion have not been fully characterized. However, it has been demonstrated in an antidepressant screening test in mice that hydroxybupropion is one-half as potent as bupropion, while threohydrobupropion and erythrohydrobupropion are 5-fold less potent than bupropion. This may be of clinical importance because the plasma concentrations of the metabolites are as high as or higher than those of bupropion. Bupropion and its metabolites exhibit linear kinetics following chronic administration of 300 to 450 mg per day. •Metabolism (Drug B): Intravenous studies using a single dose of metformin in normal subjects show that metformin is excreted as unchanged drug in the urine and does not undergo hepatic metabolism (no metabolites have been identified in humans) or biliary excretion. •Route of elimination (Drug A): Bupropion is extensively metabolized in humans. Oxidation of the bupropion side chain results in the formation of a glycine conjugate of metachlorobenzoic acid, which is then excreted as the major urinary metabolite. Following oral administration of 200 mg of 14C-bupropion in humans, 87% and 10% of the radioactive dose were recovered in the urine and feces, respectively. However, the fraction of the oral dose of bupropion excreted unchanged was only 0.5%, a finding consistent with the extensive metabolism of bupropion. •Route of elimination (Drug B): This drug is substantially excreted by the kidney. Renal clearance of metformin is about 3.5 times higher than creatinine clearance, which shows that renal tubular secretion is the major route of metformin elimination. After oral administration, about 90% of absorbed metformin is eliminated by the kidneys within the first 24 hours post-ingestion. •Half-life (Drug A): 24 hours •Half-life (Drug B): The plasma elimination half-life of metformin is 6.2 hours in the plasma. The elimination half-life in the blood is approximately 17.6 hours, suggesting that the erythrocyte mass may be a compartment of distribution. •Clearance (Drug A): No clearance available •Clearance (Drug B): Renal clearance is about 3.5 times greater than creatinine clearance, which indicates that tubular secretion is the major route of metformin elimination. Following oral administration, approximately 90% of the absorbed drug is eliminated via the renal route within the first 24 hours. •Toxicity (Drug A): Symptoms of overdose include seizures, hallucinations, loss of consciousness, tachycardia, and cardiac arrest. •Toxicity (Drug B): Metformin (hydrochloride) toxicity data: Oral LD50 (rat): 1 g/kg; Intraperitoneal LD50 (rat): 500 mg/kg; Subcutaneous LD50 (rat): 300 mg/kg; Oral LD50 (mouse): 1450 mg/kg; Intraperitoneal LD50 (mouse): 420 mg/kg; Subcutaneous LD50 (mouse): 225 mg/kg. A note on lactic acidosis Metformin decreases liver uptake of lactate, thereby increasing lactate blood levels which may increase the risk of lactic acidosis. There have been reported postmarketing cases of metformin-associated lactic acidosis, including some fatal cases. Such cases had a subtle onset and were accompanied by nonspecific symptoms including malaise, myalgias, abdominal pain, respiratory distress, or increased somnolence. In certain cases, hypotension and resistant bradyarrhythmias have occurred with severe lactic acidosis. Metformin-associated lactic acidosis was characterized by elevated blood lactate concentrations (>5 mmol/L), anion gap acidosis (without evidence of ketonuria or ketonemia), as well as an increased lactate:pyruvate ratio; metformin plasma levels were generally >5 mcg/mL. Risk factors for metformin-associated lactic acidosis include renal impairment, concomitant use of certain drugs (e.g. carbonic anhydrase inhibitors such as topiramate), age 65 years old or greater, having a radiological study with contrast, surgery and other procedures, hypoxic states (e.g., acute congestive heart failure), excessive alcohol intake, and hepatic impairment. A note on renal function In patients with decreased renal function, the plasma and blood half-life of metformin is prolonged and the renal clearance is decreased. Metformin should be avoided in those with severely compromised renal function (creatinine clearance < 30 ml/min), acute/decompensated heart failure, severe liver disease and for 48 hours after the use of iodinated contrast dyes due to the risk of lactic acidosis. Lower doses should be used in the elderly and those with decreased renal function. Metformin decreases fasting plasma glucose, postprandial blood glucose and glycosolated hemoglobin (HbA1c) levels, which are reflective of the last 8-10 weeks of glucose control. Metformin may also have a positive effect on lipid levels. A note on hypoglycemia When used alone, metformin does not cause hypoglycemia, however, it may potentiate the hypoglycemic effects of sulfonylureas and insulin when they are used together. Use in pregnancy Available data from post-marketing studies have not indicated a clear association of metformin with major birth defects, miscarriage, or adverse maternal or fetal outcomes when metformin was ingested during pregnancy. Despite this, the abovementioned studies cannot definitively establish the absence of any metformin-associated risk due to methodological limitations, including small sample size and inconsistent study groups. Use in nursing A limited number of published studies indicate that metformin is present in human milk. There is insufficient information to confirm the effects of metformin on the nursing infant and no available data on the effects of metformin on the production of milk. The developmental and health benefits of breastfeeding should be considered as well as the mother’s clinical need for metformin and any possible adverse effects on the nursing child. •Brand Names (Drug A): Aplenzin, Auvelity, Budeprion, Contrave, Forfivo, Wellbutrin, Zyban •Brand Names (Drug B): Actoplus Met, Avandamet, Fortamet, Glucophage, Glucovance, Glumetza, Glycon, Invokamet, Janumet, Jentadueto, Kazano, Kombiglyze, Komboglyze, Qternmet, Riomet, Segluromet, Synjardy, Trijardy, Velmetia, Xigduo, Zituvimet •Synonyms (Drug A): No synonyms listed •Synonyms (Drug B): Dimethylbiguanid Metformin Metformina Metformine Metforminum •Summary (Drug A): Bupropion is a norepinephrine and dopamine reuptake inhibitor used in the treatment of major depressive disorder (MDD), seasonal affective disorder (SAD), and as an aid to smoking cessation. •Summary (Drug B): Metformin is a biguanide antihyperglycemic used in conjunction with diet and exercise for glycemic control in type 2 diabetes mellitus. It is also used off-label for insulin resistance in polycystic ovary syndrome (PCOS).

Findings from in vitro studies showed that bupropion and its metabolites inhibit OCT2, suggesting that clinically relevant interaction through inhibition of OCT2 could occur at therapeutic bupropion doses. Co-administration of bupropion with OCT2 substrates may result in attenuated OCT2-mediated efflux of those drugs, thereby increasing drug serum concentrations. The severity of the interaction is moderate.

Question: Does Bupropion and Metformin interact? Information: •Drug A: Bupropion •Drug B: Metformin •Severity: MODERATE •Description: The excretion of Metformin can be decreased when combined with Bupropion. •Extended Description: Findings from in vitro studies showed that bupropion and its metabolites inhibit OCT2, suggesting that clinically relevant interaction through inhibition of OCT2 could occur at therapeutic bupropion doses. Co-administration of bupropion with OCT2 substrates may result in attenuated OCT2-mediated efflux of those drugs, thereby increasing drug serum concentrations. •Indication (Drug A): Bupropion is indicated for the treatment of major depressive disorder (MDD), seasonal affective disorder (SAD), and as an aid to smoking cessation. When used in combination with naltrexone as the marketed product ContraveⓇ, bupropion is indicated as an adjunct to a reduced-calorie diet and increased physical activity for chronic weight management in adults with an initial body mass index (BMI) of: 30 kg/m^2 or greater (obese) or 27 kg/m^2 or greater (overweight) in the presence of at least one weight-related comorbid condition (e.g., hypertension, type 2 diabetes mellitus, or dyslipidemia). Bupropion is also used off-label as a first-line treatment in patients with ADHD and comorbid bipolar disorder when used as an adjunct to mood stabilizers. •Indication (Drug B): Metformin immediate-release formulations Metformin is indicated as an adjunct to diet and exercise to improve glycemic control in adults and pediatric patients ≥10 years old with type 2 diabetes mellitus. Metformin extended-release tablet (XR) The extended-release formulation of metformin is indicated as an adjunct to diet and exercise to improve glycemic control in adults with type 2 diabetes mellitus. Safety in children has not been determined to this date. Metformin combination products Metformin is a component of a variety of combination products with other anti-diabetic agents. It is indicated, along with diet and exercise, to improve glycemic control in adult patients with type 2 diabetes mellitus in combination with DPP-4 inhibitors ( sitagliptin, linagliptin, alogliptin, or saxagliptin ), in combination with SGLT2 inhibitors ( canagliflozin, empagliflozin, ertugliflozin, or dapagliflozin ), or in combination with pioglitazone. •Pharmacodynamics (Drug A): Bupropion is chemically unrelated to tricyclic, tetracyclic, selective serotonin re-uptake inhibitors, or other known antidepressant agents. Compared to classical tricyclic antidepressants, Bupropion is a relatively weak inhibitor of the neuronal uptake of norepinephrine and dopamine. In addition, Bupropion does not inhibit monoamine oxidase. Bupropion has been found to be essentially inactive at the serotonin transporter (SERT)(IC50 >10 000 nM), however both bupropion and its primary metabolite hydroxybupropion have been found to block the function of cation-selective serotonin type 3A receptors (5-HT3ARs). Bupropion produces dose-related central nervous system (CNS) stimulant effects in animals, as evidenced by increased locomotor activity, increased rates of responding in various schedule-controlled operant behaviour tasks, and, at high doses, induction of mild stereotyped behaviour. Due to these stimulant effects and selective activity at dopamine and norepinephrine receptors, bupropion has been identified as having an abuse potential. Bupropion has a similar structure to the controlled substance Cathinone, and has been identified as having mild amphetamine-like activity, particularly when inhaled or injected. Bupropion is also known to lower the seizure threshold, making any pre-existing seizure conditions a contraindication to its use. This risk is exacerbated when bupropion is combined with other drugs or substances that lower the seizure threshold, such as cocaine, or in clinical situations that would increase the risk of a seizure such as abrupt alcohol or benzodiazepine withdrawal. As norepinephrine has been shown to have anticonvulsant properties, bupropion's inhibitory effects on NET are thought to contribute to its pro-convulsant activity. Bupropion has been shown to increase blood pressure and pose a risk for exacerbation of unmanaged or pre-existing hypertension, however, clinical trials of bupropion in smokers with CVD have not identified an increased incidence of CV events including stroke or heart attack. In clinical trials, the mean increase in systolic blood pressure associated with the use of bupropion was found to be 1.3 mmHg. •Pharmacodynamics (Drug B): General effects Insulin is an important hormone that regulates blood glucose levels. Type II diabetes is characterized by a decrease in sensitivity to insulin, resulting in elevations in blood glucose when the pancreas can no longer compensate. In patients diagnosed with type 2 diabetes, insulin is unable to exert adequate effects on tissues and cells (i.e. insulin resistance) and insulin deficiency may also be present. Metformin reduces hepatic production of glucose, decreases the intestinal absorption of glucose, and enhances insulin sensitivity by increasing both peripheral glucose uptake and utilization. In contrast with drugs of the sulfonylurea class, which lead to hyperinsulinemia, the secretion of insulin is unchanged with metformin use. Effect on fasting plasma glucose (FPG) and Glycosylated hemoglobin (HbA1c) HbA1c is an important periodic measure of glycemic control used to monitor diabetic patients. Fasting plasma glucose is also a useful and important measure of glycemic control. In a 29-week clinical trial of subjects diagnosed with type II diabetes, metformin decreased the fasting plasma glucose levels by an average of 59 mg/dL from baseline, compared to an average increase of 6.3 mg/dL from baseline in subjects taking a placebo. Glycosylated hemoglobin (HbA1c) was decreased by about 1.4% in subjects receiving metformin, and increased by 0.4% in subjects receiving placebo only. •Mechanism of action (Drug A): Bupropion is a norepinephrine/dopamine-reuptake inhibitor (NDRI) that exerts its pharmacological effects by weakly inhibiting the enzymes involved in the uptake of the neurotransmitters norepinephrine and dopamine from the synaptic cleft, therefore prolonging their duration of action within the neuronal synapse and the downstream effects of these neurotransmitters. More specifically, bupropion binds to the norepinephrine transporter (NET) and the dopamine transporter (DAT). Bupropion was originally classified as an "atypical" antidepressant because it does not exert the same effects as the classical antidepressants such as Monoamine Oxidase Inhibitors (MAOIs), Tricyclic Antidepressants (TCAs), or Selective Serotonin Reuptake Inhibitors (SSRIs). While it has comparable effectiveness to typical first-line options for the treatment of depression such as SSRIs, bupropion is a unique option for the treatment of MDD as it lacks any clinically relevant serotonergic effects, typical of other mood medications, or any effects on histamine or adrenaline receptors. Lack of activity at these receptors results in a more tolerable side effect profile; bupropion is less likely to cause sexual side effects, sedation, or weight gain as compared to SSRIs or TCAs, for example. When used as an aid to smoking cessation, bupropion is thought to confer its anti-craving and anti-withdrawal effects by inhibiting dopamine reuptake, which is thought to be involved in the reward pathways associated with nicotine, and through the antagonism of the nicotinic acetylcholinergic receptor (AChR), thereby blunting the effects of nicotine. Furthermore, the stimulatory effects produced by bupropion in the central nervous system are similar to nicotine's effects, making low doses of bupropion a suitable option as a nicotine substitute. When used in combination with naltrexone in the marketed product ContraveⓇ for chronic weight management, the two components are thought to have effects on areas of the brain involved in the regulation of food intake. This includes the hypothalamus, which is involved in appetite regulation, and the mesolimbic dopamine circuit, which is involved in reward pathways. Studies have shown that the combined activity of bupropion and naltrexone increase the firing rate of hypothalamic pro-opiomelanocortin (POMC) neurons and blockade of opioid receptor-mediated POMC auto-inhibition, which are associated with a reduction in food intake and increased energy expenditure. This combination was also found to reduce food intake when injected directly into the ventral tegmental area of the mesolimbic circuit in mice, which is an area associated with the regulation of reward pathways. •Mechanism of action (Drug B): Metformin's mechanisms of action are unique from other classes of oral antihyperglycemic drugs. Metformin decreases blood glucose levels by decreasing hepatic glucose production (also called gluconeogenesis), decreasing the intestinal absorption of glucose, and increasing insulin sensitivity by increasing peripheral glucose uptake and utilization. It is well established that metformin inhibits mitochondrial complex I activity, and it has since been generally postulated that its potent antidiabetic effects occur through this mechanism. The above processes lead to a decrease in blood glucose, managing type II diabetes and exerting positive effects on glycemic control. After ingestion, the organic cation transporter-1 (OCT1) is responsible for the uptake of metformin into hepatocytes (liver cells). As this drug is positively charged, it accumulates in cells and in the mitochondria because of the membrane potentials across the plasma membrane as well as the mitochondrial inner membrane. Metformin inhibits mitochondrial complex I, preventing the production of mitochondrial ATP leading to increased cytoplasmic ADP:ATP and AMP:ATP ratios. These changes activate AMP-activated protein kinase (AMPK), an enzyme that plays an important role in the regulation of glucose metabolism. Aside from this mechanism, AMPK can be activated by a lysosomal mechanism involving other activators. Following this process, increases in AMP:ATP ratio also inhibit fructose-1,6-bisphosphatase enzyme, resulting in the inhibition of gluconeogenesis, while also inhibiting adenylate cyclase and decreasing the production of cyclic adenosine monophosphate (cAMP), a derivative of ATP used for cell signaling. Activated AMPK phosphorylates two isoforms of acetyl-CoA carboxylase enzyme, thereby inhibiting fat synthesis and leading to fat oxidation, reducing hepatic lipid stores and increasing liver sensitivity to insulin. In the intestines, metformin increases anaerobic glucose metabolism in enterocytes (intestinal cells), leading to reduced net glucose uptake and increased delivery of lactate to the liver. Recent studies have also implicated the gut as a primary site of action of metformin and suggest that the liver may not be as important for metformin action in patients with type 2 diabetes. Some of the ways metformin may play a role on the intestines is by promoting the metabolism of glucose by increasing glucagon-like peptide I (GLP-1) as well as increasing gut utilization of glucose. In addition to the above pathway, the mechanism of action of metformin may be explained by other ways, and its exact mechanism of action has been under extensive study in recent years. •Absorption (Drug A): Bupropion is currently available in 3 distinct, but bioequivalent formulations: immediate release (IR), sustained-release (SR), and extended-release (XL). Immediate Release Formulation In humans, following oral administration of bupropion hydrochloride tablets, peak plasma bupropion concentrations are usually achieved within 2 hours. IR formulations provide a short duration of action and are therefore generally dosed three times per day. Sustained Release Formulation In humans, following oral administration of bupropion hydrochloride sustained-release tablets (SR), peak plasma concentration (Cmax) of bupropion is usually achieved within 3 hours. SR formulations provide a 12-hour extended release of medication and are therefore generally dosed twice per day. Extended Release Formulation Following single oral administration of bupropion hydrochloride extended-release tablets (XL) to healthy volunteers, the median time to peak plasma concentrations for bupropion was approximately 5 hours. The presence of food did not affect the peak concentration or area under the curve of bupropion. XL formulations provide a 24-hour extended release of medication and are therefore generally dosed once per day/ In a trial comparing chronic dosing with bupropion hydrochloride extended-release tablets (SR) 150 mg twice daily to bupropion immediate-release formulation 100 mg 3 times daily, the steady state Cmax for bupropion after bupropion hydrochloride sustained-release tablets (SR) administration was approximately 85% of those achieved after bupropion immediate-release formulation administration. Exposure (AUC) to bupropion was equivalent for both formulations. Bioequivalence was also demonstrated for all three major active metabolites (i.e., hydroxybupropion, threohydrobupropion and erythrohydrobupropion) for both Cmax and AUC. Thus, at steady state, bupropion hydrochloride sustained-release tablets (SR) given twice daily, and the immediate-release formulation of bupropion given 3 times daily, are essentially bioequivalent for both bupropion and the 3 quantitatively important metabolites. Furthermore, in a study comparing 14-day dosing with bupropion hydrochloride extended-release tablets (XL), 300 mg once-daily to the immediate-release formulation of bupropion at 100 mg 3 times daily, equivalence was demonstrated for peak plasma concentration and area under the curve for bupropion and the three metabolites (hydroxybupropion, threohydrobupropion, and erythrohydrobupropion). Additionally, in a study comparing 14-day dosing with bupropion hydrochloride extended-release tablets (XL) 300 mg once daily to the sustained-release formulation of bupropion at 150 mg 2 times daily, equivalence was demonstrated for peak plasma concentration and area under the curve for bupropion and the three metabolites. Bupropion hydrochloride extended-release tablets (SR) can be taken with or without food. Bupropion Cmax and AUC were increased by 11% to 35% and 16% to 19%, respectively, when bupropion hydrochloride extended-release tablets (SR) was administered with food to healthy volunteers in three trials. The food effect is not considered clinically significant. Following a single-dose administration of bupropion hydrochloride extended-release tablets (SR) in humans, Cmax of bupropion's metabolite hydroxybupropion occurs approximately 6 hours post-dose and is approximately 10 times the peak level of the parent drug at steady state. The elimination half-life of hydroxybupropion is approximately 20 (±5) hours and its AUC at steady state is about 17 times that of bupropion. The times to peak concentrations for the erythrohydrobupropion and threohydrobupropion metabolites are similar to that of the hydroxybupropion metabolite. However, their elimination half-lives are longer, 33(±10) and 37 (±13) hours, respectively, and steady-state AUCs are 1.5 and 7 times that of bupropion, respectively. •Absorption (Drug B): Regular tablet absorption The absolute bioavailability of a metformin 500 mg tablet administered in the fasting state is about 50%-60%. Single-dose clinical studies using oral doses of metformin 500 to 1500 mg and 850 to 2550 mg show that there is a lack of dose proportionality with an increase in metformin dose, attributed to decreased absorption rather than changes in elimination. At usual clinical doses and dosing schedules of metformin, steady-state plasma concentrations of metformin are achieved within 24-48 hours and are normally measured at <1 μg/mL. Extended-release tablet absorption After a single oral dose of metformin extended-release, Cmax is reached with a median value of 7 hours and a range of between 4 and 8 hours. Peak plasma levels are measured to be about 20% lower compared to the same dose of regular metformin, however, the extent of absorption of both forms (as measured by area under the curve - AUC), are similar. Effect of food Food reduces the absorption of metformin, as demonstrated by about a 40% lower mean peak plasma concentration (Cmax), a 25% lower area under the plasma concentration versus time curve (AUC), and a 35-minute increase in time to peak plasma concentration (Tmax) after ingestion of an 850 mg tablet of metformin taken with food, compared to the same dose administered during fasting. Though the extent of metformin absorption (measured by the area under the curve - AUC) from the metformin extended-release tablet is increased by about 50% when given with food, no effect of food on Cmax and Tmax of metformin is observed. High and low-fat meals exert similar effects on the pharmacokinetics of extended-release metformin. •Volume of distribution (Drug A): No volume of distribution available •Volume of distribution (Drug B): The apparent volume of distribution (V/F) of metformin after one oral dose of metformin 850 mg averaged at 654 ± 358 L. •Protein binding (Drug A): In vitro tests show that bupropion is 84% bound to human plasma proteins at concentrations up to 200 mcg per mL. The extent of protein binding of the hydroxybupropion metabolite is similar to that for bupropion, whereas the extent of protein binding of the threohydrobupropion metabolite is about half that seen with bupropion. •Protein binding (Drug B): Metformin is negligibly bound to plasma proteins. •Metabolism (Drug A): Bupropion is extensively metabolized in humans. Three metabolites are active: hydroxybupropion, which is formed via hydroxylation of the tert-butyl group of bupropion, and the amino-alcohol isomers, threohydrobupropion and erythrohydrobupropion, which are formed via reduction of the carbonyl group. In vitro findings suggest that CYP2B6 is the principal isoenzyme involved in the formation of hydroxybupropion, while cytochrome P450 enzymes are not involved in the formation of threohydrobupropion. Hydroxybupropion has been shown to have the same affinity as bupropion for the norepinephrine transporter (NET) but approximately 50% of its antidepressant activity despite reaching concentrations of ~10-fold higher than that of the parent drug. Oxidation of the bupropion side chain results in the formation of a glycine conjugate of meta-chlorobenzoic acid, which is then excreted as the major urinary metabolite. The potency and toxicity of the metabolites relative to bupropion have not been fully characterized. However, it has been demonstrated in an antidepressant screening test in mice that hydroxybupropion is one-half as potent as bupropion, while threohydrobupropion and erythrohydrobupropion are 5-fold less potent than bupropion. This may be of clinical importance because the plasma concentrations of the metabolites are as high as or higher than those of bupropion. Bupropion and its metabolites exhibit linear kinetics following chronic administration of 300 to 450 mg per day. •Metabolism (Drug B): Intravenous studies using a single dose of metformin in normal subjects show that metformin is excreted as unchanged drug in the urine and does not undergo hepatic metabolism (no metabolites have been identified in humans) or biliary excretion. •Route of elimination (Drug A): Bupropion is extensively metabolized in humans. Oxidation of the bupropion side chain results in the formation of a glycine conjugate of metachlorobenzoic acid, which is then excreted as the major urinary metabolite. Following oral administration of 200 mg of 14C-bupropion in humans, 87% and 10% of the radioactive dose were recovered in the urine and feces, respectively. However, the fraction of the oral dose of bupropion excreted unchanged was only 0.5%, a finding consistent with the extensive metabolism of bupropion. •Route of elimination (Drug B): This drug is substantially excreted by the kidney. Renal clearance of metformin is about 3.5 times higher than creatinine clearance, which shows that renal tubular secretion is the major route of metformin elimination. After oral administration, about 90% of absorbed metformin is eliminated by the kidneys within the first 24 hours post-ingestion. •Half-life (Drug A): 24 hours •Half-life (Drug B): The plasma elimination half-life of metformin is 6.2 hours in the plasma. The elimination half-life in the blood is approximately 17.6 hours, suggesting that the erythrocyte mass may be a compartment of distribution. •Clearance (Drug A): No clearance available •Clearance (Drug B): Renal clearance is about 3.5 times greater than creatinine clearance, which indicates that tubular secretion is the major route of metformin elimination. Following oral administration, approximately 90% of the absorbed drug is eliminated via the renal route within the first 24 hours. •Toxicity (Drug A): Symptoms of overdose include seizures, hallucinations, loss of consciousness, tachycardia, and cardiac arrest. •Toxicity (Drug B): Metformin (hydrochloride) toxicity data: Oral LD50 (rat): 1 g/kg; Intraperitoneal LD50 (rat): 500 mg/kg; Subcutaneous LD50 (rat): 300 mg/kg; Oral LD50 (mouse): 1450 mg/kg; Intraperitoneal LD50 (mouse): 420 mg/kg; Subcutaneous LD50 (mouse): 225 mg/kg. A note on lactic acidosis Metformin decreases liver uptake of lactate, thereby increasing lactate blood levels which may increase the risk of lactic acidosis. There have been reported postmarketing cases of metformin-associated lactic acidosis, including some fatal cases. Such cases had a subtle onset and were accompanied by nonspecific symptoms including malaise, myalgias, abdominal pain, respiratory distress, or increased somnolence. In certain cases, hypotension and resistant bradyarrhythmias have occurred with severe lactic acidosis. Metformin-associated lactic acidosis was characterized by elevated blood lactate concentrations (>5 mmol/L), anion gap acidosis (without evidence of ketonuria or ketonemia), as well as an increased lactate:pyruvate ratio; metformin plasma levels were generally >5 mcg/mL. Risk factors for metformin-associated lactic acidosis include renal impairment, concomitant use of certain drugs (e.g. carbonic anhydrase inhibitors such as topiramate), age 65 years old or greater, having a radiological study with contrast, surgery and other procedures, hypoxic states (e.g., acute congestive heart failure), excessive alcohol intake, and hepatic impairment. A note on renal function In patients with decreased renal function, the plasma and blood half-life of metformin is prolonged and the renal clearance is decreased. Metformin should be avoided in those with severely compromised renal function (creatinine clearance < 30 ml/min), acute/decompensated heart failure, severe liver disease and for 48 hours after the use of iodinated contrast dyes due to the risk of lactic acidosis. Lower doses should be used in the elderly and those with decreased renal function. Metformin decreases fasting plasma glucose, postprandial blood glucose and glycosolated hemoglobin (HbA1c) levels, which are reflective of the last 8-10 weeks of glucose control. Metformin may also have a positive effect on lipid levels. A note on hypoglycemia When used alone, metformin does not cause hypoglycemia, however, it may potentiate the hypoglycemic effects of sulfonylureas and insulin when they are used together. Use in pregnancy Available data from post-marketing studies have not indicated a clear association of metformin with major birth defects, miscarriage, or adverse maternal or fetal outcomes when metformin was ingested during pregnancy. Despite this, the abovementioned studies cannot definitively establish the absence of any metformin-associated risk due to methodological limitations, including small sample size and inconsistent study groups. Use in nursing A limited number of published studies indicate that metformin is present in human milk. There is insufficient information to confirm the effects of metformin on the nursing infant and no available data on the effects of metformin on the production of milk. The developmental and health benefits of breastfeeding should be considered as well as the mother’s clinical need for metformin and any possible adverse effects on the nursing child. •Brand Names (Drug A): Aplenzin, Auvelity, Budeprion, Contrave, Forfivo, Wellbutrin, Zyban •Brand Names (Drug B): Actoplus Met, Avandamet, Fortamet, Glucophage, Glucovance, Glumetza, Glycon, Invokamet, Janumet, Jentadueto, Kazano, Kombiglyze, Komboglyze, Qternmet, Riomet, Segluromet, Synjardy, Trijardy, Velmetia, Xigduo, Zituvimet •Synonyms (Drug A): No synonyms listed •Synonyms (Drug B): Dimethylbiguanid Metformin Metformina Metformine Metforminum •Summary (Drug A): Bupropion is a norepinephrine and dopamine reuptake inhibitor used in the treatment of major depressive disorder (MDD), seasonal affective disorder (SAD), and as an aid to smoking cessation. •Summary (Drug B): Metformin is a biguanide antihyperglycemic used in conjunction with diet and exercise for glycemic control in type 2 diabetes mellitus. It is also used off-label for insulin resistance in polycystic ovary syndrome (PCOS). Output: Findings from in vitro studies showed that bupropion and its metabolites inhibit OCT2, suggesting that clinically relevant interaction through inhibition of OCT2 could occur at therapeutic bupropion doses. Co-administration of bupropion with OCT2 substrates may result in attenuated OCT2-mediated efflux of those drugs, thereby increasing drug serum concentrations. The severity of the interaction is moderate.

Does Bupropion and Methadone interact?

•Drug A: Bupropion •Drug B: Methadone •Severity: MAJOR •Description: The risk or severity of adverse effects can be increased when Methadone is combined with Bupropion. •Extended Description: The concomitant administration of CNS depressants with methadone may produce an increase in respiratory depression, profound sedation, hypotension, coma, and other adverse effects. •Indication (Drug A): Bupropion is indicated for the treatment of major depressive disorder (MDD), seasonal affective disorder (SAD), and as an aid to smoking cessation. When used in combination with naltrexone as the marketed product ContraveⓇ, bupropion is indicated as an adjunct to a reduced-calorie diet and increased physical activity for chronic weight management in adults with an initial body mass index (BMI) of: 30 kg/m^2 or greater (obese) or 27 kg/m^2 or greater (overweight) in the presence of at least one weight-related comorbid condition (e.g., hypertension, type 2 diabetes mellitus, or dyslipidemia). Bupropion is also used off-label as a first-line treatment in patients with ADHD and comorbid bipolar disorder when used as an adjunct to mood stabilizers. •Indication (Drug B): Methadone is indicated for the management of pain severe enough to require an opioid analgesic and for which alternative treatment options are inadequate. It's recommended that use is reserved for use in patients for whom alternative treatment options (eg, nonopioid analgesics, opioid combination products) are ineffective, not tolerated, or would be otherwise inadequate to provide sufficient management of pain. Methadone is also indicated for detoxification treatment of opioid addiction (heroin or other morphine-like drugs), and for maintenance substitution treatment for opioid dependence in adults in conjunction with appropriate social and medical services. •Pharmacodynamics (Drug A): Bupropion is chemically unrelated to tricyclic, tetracyclic, selective serotonin re-uptake inhibitors, or other known antidepressant agents. Compared to classical tricyclic antidepressants, Bupropion is a relatively weak inhibitor of the neuronal uptake of norepinephrine and dopamine. In addition, Bupropion does not inhibit monoamine oxidase. Bupropion has been found to be essentially inactive at the serotonin transporter (SERT)(IC50 >10 000 nM), however both bupropion and its primary metabolite hydroxybupropion have been found to block the function of cation-selective serotonin type 3A receptors (5-HT3ARs). Bupropion produces dose-related central nervous system (CNS) stimulant effects in animals, as evidenced by increased locomotor activity, increased rates of responding in various schedule-controlled operant behaviour tasks, and, at high doses, induction of mild stereotyped behaviour. Due to these stimulant effects and selective activity at dopamine and norepinephrine receptors, bupropion has been identified as having an abuse potential. Bupropion has a similar structure to the controlled substance Cathinone, and has been identified as having mild amphetamine-like activity, particularly when inhaled or injected. Bupropion is also known to lower the seizure threshold, making any pre-existing seizure conditions a contraindication to its use. This risk is exacerbated when bupropion is combined with other drugs or substances that lower the seizure threshold, such as cocaine, or in clinical situations that would increase the risk of a seizure such as abrupt alcohol or benzodiazepine withdrawal. As norepinephrine has been shown to have anticonvulsant properties, bupropion's inhibitory effects on NET are thought to contribute to its pro-convulsant activity. Bupropion has been shown to increase blood pressure and pose a risk for exacerbation of unmanaged or pre-existing hypertension, however, clinical trials of bupropion in smokers with CVD have not identified an increased incidence of CV events including stroke or heart attack. In clinical trials, the mean increase in systolic blood pressure associated with the use of bupropion was found to be 1.3 mmHg. •Pharmacodynamics (Drug B): Overall, methadone's pharmacological actions result in analgesia, suppression of opioid withdrawal symptoms, sedation, miosis (through binding to receptors in the pupillary muscles), sweating, hypotension, bradycardia, nausea and vomiting (via binding within the chemoreceptor trigger zone), and constipation. Like many basic drugs, methadone also enters mast cells and releases histamine by a non-immunological mechanism leading to flushing, pruritus, and urticaria, which can commonly be misattributed to an allergic reaction. Compared to other opioids, methadone has fewer active metabolites and therefore a lower risk of neuropsychiatric toxicity. This means that higher doses needed to manage severe pain or addiction are less likely to result in delirium, hyperalgesia, or seizures. Similar to morphine, both methadone isomers are 5-HT(3) receptor antagonists, although l-methadone produces greater inhibition than d-methadone. Methadone's effects are reversible by naloxone with a pA2 value similar to its antagonism of morphine. Dependence and Tolerance As with other opioids, tolerance and physical dependence may develop upon repeated administration of methadone and there is a potential for development of psychological dependence. Physical dependence and tolerance reflect the neuroadaptation of the opioid receptors to chronic exposure to an opioid and are separate and distinct from abuse and addiction. Tolerance, as well as physical dependence, may develop upon repeated administration of opioids, and are not by themselves evidence of an addictive disorder or abuse. Patients on prolonged therapy should be tapered gradually from the drug if it is no longer required for pain control. Withdrawal symptoms may occur following abrupt discontinuation of therapy or upon administration of an opioid antagonist. Some of the symptoms that may be associated with abrupt withdrawal of an opioid analgesic include body aches, diarrhea, gooseflesh, loss of appetite, nausea, nervousness or restlessness, anxiety, runny nose, sneezing, tremors or shivering, stomach cramps, tachycardia, trouble with sleeping, unusual increase in sweating, palpitations, unexplained fever, weakness and yawning. Cardiac Conduction Effects Laboratory studies, both in vivo and in vitro, have demonstrated that methadone inhibits cardiac potassium channels and prolongs the QT interval. Cases of QT interval prolongation and serious arrhythmia (torsades de pointes) have been observed during treatment with methadone. These cases appear to be more commonly associated with, but not limited to, higher dose treatment (> 200 mg/day). Methadone should be administered with particular caution to patients already at risk for development of prolonged QT interval (e.g., cardiac hypertrophy, concomitant diuretic use, hypokalemia, hypomagnesemia). Careful monitoring is recommended when using methadone in patients with a history of cardiac conduction disease, those taking medications affecting cardiac conduction, and in other cases where history or physical exam suggest an increased risk of dysrhythmia. Respiratory Depression and Overdose Serious, life-threatening, or fatal respiratory depression may occur with use of methadone. Patients should be monitored for respiratory depression, especially during initiation of methadone or following a dose increase. Respiratory depression is of particular concern in elderly or debilitated patients as well as in those suffering from conditions accompanied by hypoxia or hypercapnia when even moderate therapeutic doses may dangerously decrease pulmonary ventilation. Methadone should be administered with extreme caution to patients with conditions accompanied by hypoxia, hypercapnia, or decreased respiratory reserve such as: asthma, chronic obstructive pulmonary disease or cor pulmonale, severe obesity, sleep apnea syndrome, myxedema, kyphoscoliosis, and CNS depression or coma. In these patients, even usual therapeutic doses of methadone may decrease respiratory drive while simultaneously increasing airway resistance to the point of apnea. Alternative, non-opioid analgesics should be considered, and methadone should be employed only under careful medical supervision at the lowest effective dose. Infants exposed in-utero or through breast milk are at risk of life-threatening respiratory depression upon delivery or when nursed. Methadone's peak respiratory depressant effects typically occur later, and persist longer than its peak analgesic effects, in the short-term use setting. These characteristics can contribute to cases of iatrogenic overdose, particularly during treatment initiation and dose titration. Head Injury and Increased Intracranial Pressure The respiratory depressant effects of opioids and their capacity to elevate cerebrospinal fluid pressure may be markedly exaggerated in the presence of head injury, other intracranial lesions or a pre-existing increase in intracranial pressure. Furthermore, opioids produce effects which may obscure the clinical course of patients with head injuries. In such patients, methadone must be used with caution, and only if it is deemed essential. Incomplete Cross-tolerance between Methadone and other Opioids Patients tolerant to other opioids may be incompletely tolerant to methadone. Incomplete cross-tolerance is of particular concern for patients tolerant to other µ-opioid agonists who are being converted to methadone, thus making the determination of dosing during opioid conversion complex. Deaths have been reported during conversion from chronic, high-dose treatment with other opioid agonists. A high degree of “opioid tolerance” does not eliminate the possibility of methadone overdose, iatrogenic or otherwise. Crosstolerance between morphine and methadone has been demonstrated, as steady-state plasma methadone concentrations required for effectiveness (C50%) were higher in abstinent rats previously dosed with morphine, as compared to controls. Misuse, Abuse, and Diversion of Opioids Methadone is a mu-agonist opioid with an abuse liability similar to morphine. Methadone, like morphine and other opioids used for analgesia, has the potential for being abused and is subject to criminal diversion. Methadone can be abused in a manner similar to other opioid agonists, legal or illicit. This should be considered when dispensing Methadone in situations where the clinician is concerned about an increased risk of misuse, abuse, or diversion. Hypotensive Effect The administration of methadone may result in severe hypotension in patients whose ability to maintain normal blood pressure is compromised (e.g., severe volume depletion). Gastrointestinal Effects Methadone and other morphine-like opioids have been shown to decrease bowel motility and cause constipation. This primarily occurs through agonism of opioid receptors in the gut wall. Methadone may obscure the diagnosis or clinical course of patients with acute abdominal conditions. Sexual Function/Reproduction Reproductive function in human males may be decreased by methadone treatment. Reductions in ejaculate volume and seminal vesicle and prostate secretions have been reported in methadone-treated individuals. In addition, reductions in serum testosterone levels and sperm motility, and abnormalities in sperm morphology have been reported. Long-term use of opioids may be associated with decreased sex hormone levels and symptoms such as low libido, erectile dysfunction, or infertility. •Mechanism of action (Drug A): Bupropion is a norepinephrine/dopamine-reuptake inhibitor (NDRI) that exerts its pharmacological effects by weakly inhibiting the enzymes involved in the uptake of the neurotransmitters norepinephrine and dopamine from the synaptic cleft, therefore prolonging their duration of action within the neuronal synapse and the downstream effects of these neurotransmitters. More specifically, bupropion binds to the norepinephrine transporter (NET) and the dopamine transporter (DAT). Bupropion was originally classified as an "atypical" antidepressant because it does not exert the same effects as the classical antidepressants such as Monoamine Oxidase Inhibitors (MAOIs), Tricyclic Antidepressants (TCAs), or Selective Serotonin Reuptake Inhibitors (SSRIs). While it has comparable effectiveness to typical first-line options for the treatment of depression such as SSRIs, bupropion is a unique option for the treatment of MDD as it lacks any clinically relevant serotonergic effects, typical of other mood medications, or any effects on histamine or adrenaline receptors. Lack of activity at these receptors results in a more tolerable side effect profile; bupropion is less likely to cause sexual side effects, sedation, or weight gain as compared to SSRIs or TCAs, for example. When used as an aid to smoking cessation, bupropion is thought to confer its anti-craving and anti-withdrawal effects by inhibiting dopamine reuptake, which is thought to be involved in the reward pathways associated with nicotine, and through the antagonism of the nicotinic acetylcholinergic receptor (AChR), thereby blunting the effects of nicotine. Furthermore, the stimulatory effects produced by bupropion in the central nervous system are similar to nicotine's effects, making low doses of bupropion a suitable option as a nicotine substitute. When used in combination with naltrexone in the marketed product ContraveⓇ for chronic weight management, the two components are thought to have effects on areas of the brain involved in the regulation of food intake. This includes the hypothalamus, which is involved in appetite regulation, and the mesolimbic dopamine circuit, which is involved in reward pathways. Studies have shown that the combined activity of bupropion and naltrexone increase the firing rate of hypothalamic pro-opiomelanocortin (POMC) neurons and blockade of opioid receptor-mediated POMC auto-inhibition, which are associated with a reduction in food intake and increased energy expenditure. This combination was also found to reduce food intake when injected directly into the ventral tegmental area of the mesolimbic circuit in mice, which is an area associated with the regulation of reward pathways. •Mechanism of action (Drug B): Methadone is a synthetic opioid analgesic with full agonist activity at the µ-opioid receptor. While agonism of the µ-opioid receptor is the primary mechanism of action for the treatment of pain, methadone also acts as an agonist of κ- and σ-opioid receptors within the central and peripheral nervous systems. Interestingly, methadone differs from morphine (which is considered the gold standard reference opioid) in its antagonism of the N-methyl-D-aspartate (NMDA) receptor and its strong inhibition of serotonin and norepinephrine uptake, which likely also contributes to its antinociceptive activity. Methadone is administered as a 50:50 racemic mixture of (R)- and (S)-stereoisomers, with (R)-methadone demonstrating ~10-fold higher affinity and potency for the µ-opioid receptor than the (S) stereoisomer. The analgesic activity of the racemate is almost entirely due to the (R)-isomer, while the (S)-isomer lacks significant respiratory depressant activity but does have antitussive effects. While methadone shares similar effects and risks of other opioids such as morphine, hydromorphone, oxycodone, and fentanyl it has a number of unique pharmacokinetic and pharmacodynamic properties that distinguish it from them and make it a useful agent for the treatment of opioid addiction. For example, methadone abstinence syndrome, although qualitatively similar to that of morphine, differs in that the onset is slower, the course is more prolonged, and the symptoms are less severe. •Absorption (Drug A): Bupropion is currently available in 3 distinct, but bioequivalent formulations: immediate release (IR), sustained-release (SR), and extended-release (XL). Immediate Release Formulation In humans, following oral administration of bupropion hydrochloride tablets, peak plasma bupropion concentrations are usually achieved within 2 hours. IR formulations provide a short duration of action and are therefore generally dosed three times per day. Sustained Release Formulation In humans, following oral administration of bupropion hydrochloride sustained-release tablets (SR), peak plasma concentration (Cmax) of bupropion is usually achieved within 3 hours. SR formulations provide a 12-hour extended release of medication and are therefore generally dosed twice per day. Extended Release Formulation Following single oral administration of bupropion hydrochloride extended-release tablets (XL) to healthy volunteers, the median time to peak plasma concentrations for bupropion was approximately 5 hours. The presence of food did not affect the peak concentration or area under the curve of bupropion. XL formulations provide a 24-hour extended release of medication and are therefore generally dosed once per day/ In a trial comparing chronic dosing with bupropion hydrochloride extended-release tablets (SR) 150 mg twice daily to bupropion immediate-release formulation 100 mg 3 times daily, the steady state Cmax for bupropion after bupropion hydrochloride sustained-release tablets (SR) administration was approximately 85% of those achieved after bupropion immediate-release formulation administration. Exposure (AUC) to bupropion was equivalent for both formulations. Bioequivalence was also demonstrated for all three major active metabolites (i.e., hydroxybupropion, threohydrobupropion and erythrohydrobupropion) for both Cmax and AUC. Thus, at steady state, bupropion hydrochloride sustained-release tablets (SR) given twice daily, and the immediate-release formulation of bupropion given 3 times daily, are essentially bioequivalent for both bupropion and the 3 quantitatively important metabolites. Furthermore, in a study comparing 14-day dosing with bupropion hydrochloride extended-release tablets (XL), 300 mg once-daily to the immediate-release formulation of bupropion at 100 mg 3 times daily, equivalence was demonstrated for peak plasma concentration and area under the curve for bupropion and the three metabolites (hydroxybupropion, threohydrobupropion, and erythrohydrobupropion). Additionally, in a study comparing 14-day dosing with bupropion hydrochloride extended-release tablets (XL) 300 mg once daily to the sustained-release formulation of bupropion at 150 mg 2 times daily, equivalence was demonstrated for peak plasma concentration and area under the curve for bupropion and the three metabolites. Bupropion hydrochloride extended-release tablets (SR) can be taken with or without food. Bupropion Cmax and AUC were increased by 11% to 35% and 16% to 19%, respectively, when bupropion hydrochloride extended-release tablets (SR) was administered with food to healthy volunteers in three trials. The food effect is not considered clinically significant. Following a single-dose administration of bupropion hydrochloride extended-release tablets (SR) in humans, Cmax of bupropion's metabolite hydroxybupropion occurs approximately 6 hours post-dose and is approximately 10 times the peak level of the parent drug at steady state. The elimination half-life of hydroxybupropion is approximately 20 (±5) hours and its AUC at steady state is about 17 times that of bupropion. The times to peak concentrations for the erythrohydrobupropion and threohydrobupropion metabolites are similar to that of the hydroxybupropion metabolite. However, their elimination half-lives are longer, 33(±10) and 37 (±13) hours, respectively, and steady-state AUCs are 1.5 and 7 times that of bupropion, respectively. •Absorption (Drug B): Methadone is one of the more lipid-soluble opioids and is well absorbed from the gastrointestinal tract. Following oral administration of methadone, bioavailability ranges from 36-100%, with a marked interindividual variation. It can be detected in blood as soon as 15-45 minutes following administration with peak plasma concentrations achieved between 1 to 7.5 hours. A second peak is observed ~4 hours after administration and is likely due to enterohepatic circulation. Dose proportionality of methadone pharmacokinetics is not known. Following administration of daily oral doses ranging from 10 to 225 mg the steady-state plasma concentrations ranged between 65 to 630 ng/mL and the peak concentrations ranged between 124 to 1255 ng/mL. Effect of food on the bioavailability of methadone has not been evaluated. Slower absorption is observed in opioid users compared to healthy subjects, which may reflect the pharmacological effect of opioids in slowing gastric emptying and mobility. Due to the large inter-individual variation in methadone pharmacokinetics and pharmacodynamics, treatment should be individualized to each patient. There was an up to 17-fold interindividual variation found in methadone blood concentrations for a given dosage, likely due in part to individual variability in CYP enzyme function. There is also a large variability in pharmacokinetics between methadone's enantiomers, which further complicates pharmacokinetic interpretation and study. •Volume of distribution (Drug A): No volume of distribution available •Volume of distribution (Drug B): Due to interindividual differences in pharmacokinetics, estimates of methadone's volume of distribution have ranged from 189-470 L with monographs listing it between 1.0-8.0L/kg. As this is higher than physiological volumes of total body water, methadone is highly distributed in the body including brain, gut, kidney, liver, muscle, and lung. A population pharmacokinetic study found that subject gender and weight explained ~33% of the variance in the apparent volume of distribution of methadone. Methadone is found to be secreted in saliva, sweat, breast milk, amniotic fluid and umbilical cord plasma. The concentration in cord blood is about half the maternal levels. •Protein binding (Drug A): In vitro tests show that bupropion is 84% bound to human plasma proteins at concentrations up to 200 mcg per mL. The extent of protein binding of the hydroxybupropion metabolite is similar to that for bupropion, whereas the extent of protein binding of the threohydrobupropion metabolite is about half that seen with bupropion. •Protein binding (Drug B): Methadone is highly bound to plasma proteins. While it primarily binds to α1-acid glycoprotein (85-90%), it also binds to albumin and other tissue and plasma proteins including lipoproteins. Methadone is unusual in the opioid class, in that there is extensive binding to tissue proteins and fairly slow transfer between some parts of this tissue reservoir and the plasma. •Metabolism (Drug A): Bupropion is extensively metabolized in humans. Three metabolites are active: hydroxybupropion, which is formed via hydroxylation of the tert-butyl group of bupropion, and the amino-alcohol isomers, threohydrobupropion and erythrohydrobupropion, which are formed via reduction of the carbonyl group. In vitro findings suggest that CYP2B6 is the principal isoenzyme involved in the formation of hydroxybupropion, while cytochrome P450 enzymes are not involved in the formation of threohydrobupropion. Hydroxybupropion has been shown to have the same affinity as bupropion for the norepinephrine transporter (NET) but approximately 50% of its antidepressant activity despite reaching concentrations of ~10-fold higher than that of the parent drug. Oxidation of the bupropion side chain results in the formation of a glycine conjugate of meta-chlorobenzoic acid, which is then excreted as the major urinary metabolite. The potency and toxicity of the metabolites relative to bupropion have not been fully characterized. However, it has been demonstrated in an antidepressant screening test in mice that hydroxybupropion is one-half as potent as bupropion, while threohydrobupropion and erythrohydrobupropion are 5-fold less potent than bupropion. This may be of clinical importance because the plasma concentrations of the metabolites are as high as or higher than those of bupropion. Bupropion and its metabolites exhibit linear kinetics following chronic administration of 300 to 450 mg per day. •Metabolism (Drug B): Methadone undergoes fairly extensive first-pass metabolism. Cytochrome P450 enzymes, primarily CYP3A4, CYP2B6, and CYP2C19 and to a lesser extent CYP2C9, CYP2C8, and CYP2D6, are responsible for conversion of methadone to EDDP (2-ethyl-1,5-dimethyl-3,3-diphenylpyrrolidine) and other inactive metabolites, which are excreted mainly in the urine. Methadone first undergoes N-demethylation to form a highly unstable compound that spontaneously converts to EDDP through cyclization and dehydration. EDDP is then converted to 2-ethyl5-methyl-3,3-diphenyl-1-pyrroline (EDMP). Both EDDP and EDMP are inactive. The CYP isozymes also demonstrate different affinities for metabolizing the different methadone enantiomers: CYP2C19, CYP3A7, and CYP2C8 preferentially metabolize (R)-methadone while CYP2B6, CYP2D6, and CYP2C18 preferentially metabolize (S)-methadone. CYP3A4 does not have an enantiomer preference. Single nucleotide polymorphisms (SNPs) within the cytochrome P450 enzymes can impact methadone pharmacokinetics and contribute to the interindividual variation in response to methadone therapy. In particular, CYP2B6 polymorphisms have been shown to impact individual response to methadone as it is the predominant determinant involved in the N-demethylation of methadone, clearance, and the metabolic ratios of [methadone]/[EDDP]. The SNPs CYP2B6*6, *9, *11, CYP2C19*2, *3, CYP3A4*1B, and CYP3A5*3 result in increased methadone plasma concentrations, decreased N-demethylation, and decreased methadone clearance, while homozygous carriers of CYP2B6*6/*6 demonstrate diminished metabolism and clearance of methadone. See the pharmacogenomics section for further information. Pharmacogenomic effects on the CYP enzymes can be significant as the long half-life of methadone can result in some individuals having higher than normal therapeutic levels which puts them at risk of dose-related side effects. For example, elevated (R)-methadone levels can increase the risk of respiratory depression, while elevated (S)-methadone levels can increase the risk of severe cardiac arrhythmias due to prolonged QTc interval. •Route of elimination (Drug A): Bupropion is extensively metabolized in humans. Oxidation of the bupropion side chain results in the formation of a glycine conjugate of metachlorobenzoic acid, which is then excreted as the major urinary metabolite. Following oral administration of 200 mg of 14C-bupropion in humans, 87% and 10% of the radioactive dose were recovered in the urine and feces, respectively. However, the fraction of the oral dose of bupropion excreted unchanged was only 0.5%, a finding consistent with the extensive metabolism of bupropion. •Route of elimination (Drug B): The elimination of methadone is mediated by extensive biotransformation, followed by renal and fecal excretion. Unmetabolized methadone and its metabolites are excreted in urine to a variable degree. •Half-life (Drug A): 24 hours •Half-life (Drug B): Due to interindividual differences in pharmacokinetics, estimates of methadone's half-life have ranged from 15–207 hours with official monographs listing it between 7-59 hours. •Clearance (Drug A): No clearance available •Clearance (Drug B): Due to interindividual differences in pharmacokinetics, estimates of methadone's clearance have ranged from 5.9–13 L/h hours with approved monographs listing it between 1.4 to 126 L/h. •Toxicity (Drug A): Symptoms of overdose include seizures, hallucinations, loss of consciousness, tachycardia, and cardiac arrest. •Toxicity (Drug B): In severe overdosage, particularly by the intravenous route, apnea, circulatory collapse, cardiac arrest, and death may occur. •Brand Names (Drug A): Aplenzin, Auvelity, Budeprion, Contrave, Forfivo, Wellbutrin, Zyban •Brand Names (Drug B): Diskets, Dolophine, Metadol, Metadol-D, Methadose •Synonyms (Drug A): No synonyms listed •Synonyms (Drug B): Metadona Methadone Methadonum •Summary (Drug A): Bupropion is a norepinephrine and dopamine reuptake inhibitor used in the treatment of major depressive disorder (MDD), seasonal affective disorder (SAD), and as an aid to smoking cessation. •Summary (Drug B): Methadone is an opioid analgesic indicated for management of severe pain that is not responsive to alternative treatments. Also used to aid in detoxification and maintenance treatment of opioid addiction.

The concomitant administration of CNS depressants with methadone may produce an increase in respiratory depression, profound sedation, hypotension, coma, and other adverse effects. The severity of the interaction is major.

Question: Does Bupropion and Methadone interact? Information: •Drug A: Bupropion •Drug B: Methadone •Severity: MAJOR •Description: The risk or severity of adverse effects can be increased when Methadone is combined with Bupropion. •Extended Description: The concomitant administration of CNS depressants with methadone may produce an increase in respiratory depression, profound sedation, hypotension, coma, and other adverse effects. •Indication (Drug A): Bupropion is indicated for the treatment of major depressive disorder (MDD), seasonal affective disorder (SAD), and as an aid to smoking cessation. When used in combination with naltrexone as the marketed product ContraveⓇ, bupropion is indicated as an adjunct to a reduced-calorie diet and increased physical activity for chronic weight management in adults with an initial body mass index (BMI) of: 30 kg/m^2 or greater (obese) or 27 kg/m^2 or greater (overweight) in the presence of at least one weight-related comorbid condition (e.g., hypertension, type 2 diabetes mellitus, or dyslipidemia). Bupropion is also used off-label as a first-line treatment in patients with ADHD and comorbid bipolar disorder when used as an adjunct to mood stabilizers. •Indication (Drug B): Methadone is indicated for the management of pain severe enough to require an opioid analgesic and for which alternative treatment options are inadequate. It's recommended that use is reserved for use in patients for whom alternative treatment options (eg, nonopioid analgesics, opioid combination products) are ineffective, not tolerated, or would be otherwise inadequate to provide sufficient management of pain. Methadone is also indicated for detoxification treatment of opioid addiction (heroin or other morphine-like drugs), and for maintenance substitution treatment for opioid dependence in adults in conjunction with appropriate social and medical services. •Pharmacodynamics (Drug A): Bupropion is chemically unrelated to tricyclic, tetracyclic, selective serotonin re-uptake inhibitors, or other known antidepressant agents. Compared to classical tricyclic antidepressants, Bupropion is a relatively weak inhibitor of the neuronal uptake of norepinephrine and dopamine. In addition, Bupropion does not inhibit monoamine oxidase. Bupropion has been found to be essentially inactive at the serotonin transporter (SERT)(IC50 >10 000 nM), however both bupropion and its primary metabolite hydroxybupropion have been found to block the function of cation-selective serotonin type 3A receptors (5-HT3ARs). Bupropion produces dose-related central nervous system (CNS) stimulant effects in animals, as evidenced by increased locomotor activity, increased rates of responding in various schedule-controlled operant behaviour tasks, and, at high doses, induction of mild stereotyped behaviour. Due to these stimulant effects and selective activity at dopamine and norepinephrine receptors, bupropion has been identified as having an abuse potential. Bupropion has a similar structure to the controlled substance Cathinone, and has been identified as having mild amphetamine-like activity, particularly when inhaled or injected. Bupropion is also known to lower the seizure threshold, making any pre-existing seizure conditions a contraindication to its use. This risk is exacerbated when bupropion is combined with other drugs or substances that lower the seizure threshold, such as cocaine, or in clinical situations that would increase the risk of a seizure such as abrupt alcohol or benzodiazepine withdrawal. As norepinephrine has been shown to have anticonvulsant properties, bupropion's inhibitory effects on NET are thought to contribute to its pro-convulsant activity. Bupropion has been shown to increase blood pressure and pose a risk for exacerbation of unmanaged or pre-existing hypertension, however, clinical trials of bupropion in smokers with CVD have not identified an increased incidence of CV events including stroke or heart attack. In clinical trials, the mean increase in systolic blood pressure associated with the use of bupropion was found to be 1.3 mmHg. •Pharmacodynamics (Drug B): Overall, methadone's pharmacological actions result in analgesia, suppression of opioid withdrawal symptoms, sedation, miosis (through binding to receptors in the pupillary muscles), sweating, hypotension, bradycardia, nausea and vomiting (via binding within the chemoreceptor trigger zone), and constipation. Like many basic drugs, methadone also enters mast cells and releases histamine by a non-immunological mechanism leading to flushing, pruritus, and urticaria, which can commonly be misattributed to an allergic reaction. Compared to other opioids, methadone has fewer active metabolites and therefore a lower risk of neuropsychiatric toxicity. This means that higher doses needed to manage severe pain or addiction are less likely to result in delirium, hyperalgesia, or seizures. Similar to morphine, both methadone isomers are 5-HT(3) receptor antagonists, although l-methadone produces greater inhibition than d-methadone. Methadone's effects are reversible by naloxone with a pA2 value similar to its antagonism of morphine. Dependence and Tolerance As with other opioids, tolerance and physical dependence may develop upon repeated administration of methadone and there is a potential for development of psychological dependence. Physical dependence and tolerance reflect the neuroadaptation of the opioid receptors to chronic exposure to an opioid and are separate and distinct from abuse and addiction. Tolerance, as well as physical dependence, may develop upon repeated administration of opioids, and are not by themselves evidence of an addictive disorder or abuse. Patients on prolonged therapy should be tapered gradually from the drug if it is no longer required for pain control. Withdrawal symptoms may occur following abrupt discontinuation of therapy or upon administration of an opioid antagonist. Some of the symptoms that may be associated with abrupt withdrawal of an opioid analgesic include body aches, diarrhea, gooseflesh, loss of appetite, nausea, nervousness or restlessness, anxiety, runny nose, sneezing, tremors or shivering, stomach cramps, tachycardia, trouble with sleeping, unusual increase in sweating, palpitations, unexplained fever, weakness and yawning. Cardiac Conduction Effects Laboratory studies, both in vivo and in vitro, have demonstrated that methadone inhibits cardiac potassium channels and prolongs the QT interval. Cases of QT interval prolongation and serious arrhythmia (torsades de pointes) have been observed during treatment with methadone. These cases appear to be more commonly associated with, but not limited to, higher dose treatment (> 200 mg/day). Methadone should be administered with particular caution to patients already at risk for development of prolonged QT interval (e.g., cardiac hypertrophy, concomitant diuretic use, hypokalemia, hypomagnesemia). Careful monitoring is recommended when using methadone in patients with a history of cardiac conduction disease, those taking medications affecting cardiac conduction, and in other cases where history or physical exam suggest an increased risk of dysrhythmia. Respiratory Depression and Overdose Serious, life-threatening, or fatal respiratory depression may occur with use of methadone. Patients should be monitored for respiratory depression, especially during initiation of methadone or following a dose increase. Respiratory depression is of particular concern in elderly or debilitated patients as well as in those suffering from conditions accompanied by hypoxia or hypercapnia when even moderate therapeutic doses may dangerously decrease pulmonary ventilation. Methadone should be administered with extreme caution to patients with conditions accompanied by hypoxia, hypercapnia, or decreased respiratory reserve such as: asthma, chronic obstructive pulmonary disease or cor pulmonale, severe obesity, sleep apnea syndrome, myxedema, kyphoscoliosis, and CNS depression or coma. In these patients, even usual therapeutic doses of methadone may decrease respiratory drive while simultaneously increasing airway resistance to the point of apnea. Alternative, non-opioid analgesics should be considered, and methadone should be employed only under careful medical supervision at the lowest effective dose. Infants exposed in-utero or through breast milk are at risk of life-threatening respiratory depression upon delivery or when nursed. Methadone's peak respiratory depressant effects typically occur later, and persist longer than its peak analgesic effects, in the short-term use setting. These characteristics can contribute to cases of iatrogenic overdose, particularly during treatment initiation and dose titration. Head Injury and Increased Intracranial Pressure The respiratory depressant effects of opioids and their capacity to elevate cerebrospinal fluid pressure may be markedly exaggerated in the presence of head injury, other intracranial lesions or a pre-existing increase in intracranial pressure. Furthermore, opioids produce effects which may obscure the clinical course of patients with head injuries. In such patients, methadone must be used with caution, and only if it is deemed essential. Incomplete Cross-tolerance between Methadone and other Opioids Patients tolerant to other opioids may be incompletely tolerant to methadone. Incomplete cross-tolerance is of particular concern for patients tolerant to other µ-opioid agonists who are being converted to methadone, thus making the determination of dosing during opioid conversion complex. Deaths have been reported during conversion from chronic, high-dose treatment with other opioid agonists. A high degree of “opioid tolerance” does not eliminate the possibility of methadone overdose, iatrogenic or otherwise. Crosstolerance between morphine and methadone has been demonstrated, as steady-state plasma methadone concentrations required for effectiveness (C50%) were higher in abstinent rats previously dosed with morphine, as compared to controls. Misuse, Abuse, and Diversion of Opioids Methadone is a mu-agonist opioid with an abuse liability similar to morphine. Methadone, like morphine and other opioids used for analgesia, has the potential for being abused and is subject to criminal diversion. Methadone can be abused in a manner similar to other opioid agonists, legal or illicit. This should be considered when dispensing Methadone in situations where the clinician is concerned about an increased risk of misuse, abuse, or diversion. Hypotensive Effect The administration of methadone may result in severe hypotension in patients whose ability to maintain normal blood pressure is compromised (e.g., severe volume depletion). Gastrointestinal Effects Methadone and other morphine-like opioids have been shown to decrease bowel motility and cause constipation. This primarily occurs through agonism of opioid receptors in the gut wall. Methadone may obscure the diagnosis or clinical course of patients with acute abdominal conditions. Sexual Function/Reproduction Reproductive function in human males may be decreased by methadone treatment. Reductions in ejaculate volume and seminal vesicle and prostate secretions have been reported in methadone-treated individuals. In addition, reductions in serum testosterone levels and sperm motility, and abnormalities in sperm morphology have been reported. Long-term use of opioids may be associated with decreased sex hormone levels and symptoms such as low libido, erectile dysfunction, or infertility. •Mechanism of action (Drug A): Bupropion is a norepinephrine/dopamine-reuptake inhibitor (NDRI) that exerts its pharmacological effects by weakly inhibiting the enzymes involved in the uptake of the neurotransmitters norepinephrine and dopamine from the synaptic cleft, therefore prolonging their duration of action within the neuronal synapse and the downstream effects of these neurotransmitters. More specifically, bupropion binds to the norepinephrine transporter (NET) and the dopamine transporter (DAT). Bupropion was originally classified as an "atypical" antidepressant because it does not exert the same effects as the classical antidepressants such as Monoamine Oxidase Inhibitors (MAOIs), Tricyclic Antidepressants (TCAs), or Selective Serotonin Reuptake Inhibitors (SSRIs). While it has comparable effectiveness to typical first-line options for the treatment of depression such as SSRIs, bupropion is a unique option for the treatment of MDD as it lacks any clinically relevant serotonergic effects, typical of other mood medications, or any effects on histamine or adrenaline receptors. Lack of activity at these receptors results in a more tolerable side effect profile; bupropion is less likely to cause sexual side effects, sedation, or weight gain as compared to SSRIs or TCAs, for example. When used as an aid to smoking cessation, bupropion is thought to confer its anti-craving and anti-withdrawal effects by inhibiting dopamine reuptake, which is thought to be involved in the reward pathways associated with nicotine, and through the antagonism of the nicotinic acetylcholinergic receptor (AChR), thereby blunting the effects of nicotine. Furthermore, the stimulatory effects produced by bupropion in the central nervous system are similar to nicotine's effects, making low doses of bupropion a suitable option as a nicotine substitute. When used in combination with naltrexone in the marketed product ContraveⓇ for chronic weight management, the two components are thought to have effects on areas of the brain involved in the regulation of food intake. This includes the hypothalamus, which is involved in appetite regulation, and the mesolimbic dopamine circuit, which is involved in reward pathways. Studies have shown that the combined activity of bupropion and naltrexone increase the firing rate of hypothalamic pro-opiomelanocortin (POMC) neurons and blockade of opioid receptor-mediated POMC auto-inhibition, which are associated with a reduction in food intake and increased energy expenditure. This combination was also found to reduce food intake when injected directly into the ventral tegmental area of the mesolimbic circuit in mice, which is an area associated with the regulation of reward pathways. •Mechanism of action (Drug B): Methadone is a synthetic opioid analgesic with full agonist activity at the µ-opioid receptor. While agonism of the µ-opioid receptor is the primary mechanism of action for the treatment of pain, methadone also acts as an agonist of κ- and σ-opioid receptors within the central and peripheral nervous systems. Interestingly, methadone differs from morphine (which is considered the gold standard reference opioid) in its antagonism of the N-methyl-D-aspartate (NMDA) receptor and its strong inhibition of serotonin and norepinephrine uptake, which likely also contributes to its antinociceptive activity. Methadone is administered as a 50:50 racemic mixture of (R)- and (S)-stereoisomers, with (R)-methadone demonstrating ~10-fold higher affinity and potency for the µ-opioid receptor than the (S) stereoisomer. The analgesic activity of the racemate is almost entirely due to the (R)-isomer, while the (S)-isomer lacks significant respiratory depressant activity but does have antitussive effects. While methadone shares similar effects and risks of other opioids such as morphine, hydromorphone, oxycodone, and fentanyl it has a number of unique pharmacokinetic and pharmacodynamic properties that distinguish it from them and make it a useful agent for the treatment of opioid addiction. For example, methadone abstinence syndrome, although qualitatively similar to that of morphine, differs in that the onset is slower, the course is more prolonged, and the symptoms are less severe. •Absorption (Drug A): Bupropion is currently available in 3 distinct, but bioequivalent formulations: immediate release (IR), sustained-release (SR), and extended-release (XL). Immediate Release Formulation In humans, following oral administration of bupropion hydrochloride tablets, peak plasma bupropion concentrations are usually achieved within 2 hours. IR formulations provide a short duration of action and are therefore generally dosed three times per day. Sustained Release Formulation In humans, following oral administration of bupropion hydrochloride sustained-release tablets (SR), peak plasma concentration (Cmax) of bupropion is usually achieved within 3 hours. SR formulations provide a 12-hour extended release of medication and are therefore generally dosed twice per day. Extended Release Formulation Following single oral administration of bupropion hydrochloride extended-release tablets (XL) to healthy volunteers, the median time to peak plasma concentrations for bupropion was approximately 5 hours. The presence of food did not affect the peak concentration or area under the curve of bupropion. XL formulations provide a 24-hour extended release of medication and are therefore generally dosed once per day/ In a trial comparing chronic dosing with bupropion hydrochloride extended-release tablets (SR) 150 mg twice daily to bupropion immediate-release formulation 100 mg 3 times daily, the steady state Cmax for bupropion after bupropion hydrochloride sustained-release tablets (SR) administration was approximately 85% of those achieved after bupropion immediate-release formulation administration. Exposure (AUC) to bupropion was equivalent for both formulations. Bioequivalence was also demonstrated for all three major active metabolites (i.e., hydroxybupropion, threohydrobupropion and erythrohydrobupropion) for both Cmax and AUC. Thus, at steady state, bupropion hydrochloride sustained-release tablets (SR) given twice daily, and the immediate-release formulation of bupropion given 3 times daily, are essentially bioequivalent for both bupropion and the 3 quantitatively important metabolites. Furthermore, in a study comparing 14-day dosing with bupropion hydrochloride extended-release tablets (XL), 300 mg once-daily to the immediate-release formulation of bupropion at 100 mg 3 times daily, equivalence was demonstrated for peak plasma concentration and area under the curve for bupropion and the three metabolites (hydroxybupropion, threohydrobupropion, and erythrohydrobupropion). Additionally, in a study comparing 14-day dosing with bupropion hydrochloride extended-release tablets (XL) 300 mg once daily to the sustained-release formulation of bupropion at 150 mg 2 times daily, equivalence was demonstrated for peak plasma concentration and area under the curve for bupropion and the three metabolites. Bupropion hydrochloride extended-release tablets (SR) can be taken with or without food. Bupropion Cmax and AUC were increased by 11% to 35% and 16% to 19%, respectively, when bupropion hydrochloride extended-release tablets (SR) was administered with food to healthy volunteers in three trials. The food effect is not considered clinically significant. Following a single-dose administration of bupropion hydrochloride extended-release tablets (SR) in humans, Cmax of bupropion's metabolite hydroxybupropion occurs approximately 6 hours post-dose and is approximately 10 times the peak level of the parent drug at steady state. The elimination half-life of hydroxybupropion is approximately 20 (±5) hours and its AUC at steady state is about 17 times that of bupropion. The times to peak concentrations for the erythrohydrobupropion and threohydrobupropion metabolites are similar to that of the hydroxybupropion metabolite. However, their elimination half-lives are longer, 33(±10) and 37 (±13) hours, respectively, and steady-state AUCs are 1.5 and 7 times that of bupropion, respectively. •Absorption (Drug B): Methadone is one of the more lipid-soluble opioids and is well absorbed from the gastrointestinal tract. Following oral administration of methadone, bioavailability ranges from 36-100%, with a marked interindividual variation. It can be detected in blood as soon as 15-45 minutes following administration with peak plasma concentrations achieved between 1 to 7.5 hours. A second peak is observed ~4 hours after administration and is likely due to enterohepatic circulation. Dose proportionality of methadone pharmacokinetics is not known. Following administration of daily oral doses ranging from 10 to 225 mg the steady-state plasma concentrations ranged between 65 to 630 ng/mL and the peak concentrations ranged between 124 to 1255 ng/mL. Effect of food on the bioavailability of methadone has not been evaluated. Slower absorption is observed in opioid users compared to healthy subjects, which may reflect the pharmacological effect of opioids in slowing gastric emptying and mobility. Due to the large inter-individual variation in methadone pharmacokinetics and pharmacodynamics, treatment should be individualized to each patient. There was an up to 17-fold interindividual variation found in methadone blood concentrations for a given dosage, likely due in part to individual variability in CYP enzyme function. There is also a large variability in pharmacokinetics between methadone's enantiomers, which further complicates pharmacokinetic interpretation and study. •Volume of distribution (Drug A): No volume of distribution available •Volume of distribution (Drug B): Due to interindividual differences in pharmacokinetics, estimates of methadone's volume of distribution have ranged from 189-470 L with monographs listing it between 1.0-8.0L/kg. As this is higher than physiological volumes of total body water, methadone is highly distributed in the body including brain, gut, kidney, liver, muscle, and lung. A population pharmacokinetic study found that subject gender and weight explained ~33% of the variance in the apparent volume of distribution of methadone. Methadone is found to be secreted in saliva, sweat, breast milk, amniotic fluid and umbilical cord plasma. The concentration in cord blood is about half the maternal levels. •Protein binding (Drug A): In vitro tests show that bupropion is 84% bound to human plasma proteins at concentrations up to 200 mcg per mL. The extent of protein binding of the hydroxybupropion metabolite is similar to that for bupropion, whereas the extent of protein binding of the threohydrobupropion metabolite is about half that seen with bupropion. •Protein binding (Drug B): Methadone is highly bound to plasma proteins. While it primarily binds to α1-acid glycoprotein (85-90%), it also binds to albumin and other tissue and plasma proteins including lipoproteins. Methadone is unusual in the opioid class, in that there is extensive binding to tissue proteins and fairly slow transfer between some parts of this tissue reservoir and the plasma. •Metabolism (Drug A): Bupropion is extensively metabolized in humans. Three metabolites are active: hydroxybupropion, which is formed via hydroxylation of the tert-butyl group of bupropion, and the amino-alcohol isomers, threohydrobupropion and erythrohydrobupropion, which are formed via reduction of the carbonyl group. In vitro findings suggest that CYP2B6 is the principal isoenzyme involved in the formation of hydroxybupropion, while cytochrome P450 enzymes are not involved in the formation of threohydrobupropion. Hydroxybupropion has been shown to have the same affinity as bupropion for the norepinephrine transporter (NET) but approximately 50% of its antidepressant activity despite reaching concentrations of ~10-fold higher than that of the parent drug. Oxidation of the bupropion side chain results in the formation of a glycine conjugate of meta-chlorobenzoic acid, which is then excreted as the major urinary metabolite. The potency and toxicity of the metabolites relative to bupropion have not been fully characterized. However, it has been demonstrated in an antidepressant screening test in mice that hydroxybupropion is one-half as potent as bupropion, while threohydrobupropion and erythrohydrobupropion are 5-fold less potent than bupropion. This may be of clinical importance because the plasma concentrations of the metabolites are as high as or higher than those of bupropion. Bupropion and its metabolites exhibit linear kinetics following chronic administration of 300 to 450 mg per day. •Metabolism (Drug B): Methadone undergoes fairly extensive first-pass metabolism. Cytochrome P450 enzymes, primarily CYP3A4, CYP2B6, and CYP2C19 and to a lesser extent CYP2C9, CYP2C8, and CYP2D6, are responsible for conversion of methadone to EDDP (2-ethyl-1,5-dimethyl-3,3-diphenylpyrrolidine) and other inactive metabolites, which are excreted mainly in the urine. Methadone first undergoes N-demethylation to form a highly unstable compound that spontaneously converts to EDDP through cyclization and dehydration. EDDP is then converted to 2-ethyl5-methyl-3,3-diphenyl-1-pyrroline (EDMP). Both EDDP and EDMP are inactive. The CYP isozymes also demonstrate different affinities for metabolizing the different methadone enantiomers: CYP2C19, CYP3A7, and CYP2C8 preferentially metabolize (R)-methadone while CYP2B6, CYP2D6, and CYP2C18 preferentially metabolize (S)-methadone. CYP3A4 does not have an enantiomer preference. Single nucleotide polymorphisms (SNPs) within the cytochrome P450 enzymes can impact methadone pharmacokinetics and contribute to the interindividual variation in response to methadone therapy. In particular, CYP2B6 polymorphisms have been shown to impact individual response to methadone as it is the predominant determinant involved in the N-demethylation of methadone, clearance, and the metabolic ratios of [methadone]/[EDDP]. The SNPs CYP2B6*6, *9, *11, CYP2C19*2, *3, CYP3A4*1B, and CYP3A5*3 result in increased methadone plasma concentrations, decreased N-demethylation, and decreased methadone clearance, while homozygous carriers of CYP2B6*6/*6 demonstrate diminished metabolism and clearance of methadone. See the pharmacogenomics section for further information. Pharmacogenomic effects on the CYP enzymes can be significant as the long half-life of methadone can result in some individuals having higher than normal therapeutic levels which puts them at risk of dose-related side effects. For example, elevated (R)-methadone levels can increase the risk of respiratory depression, while elevated (S)-methadone levels can increase the risk of severe cardiac arrhythmias due to prolonged QTc interval. •Route of elimination (Drug A): Bupropion is extensively metabolized in humans. Oxidation of the bupropion side chain results in the formation of a glycine conjugate of metachlorobenzoic acid, which is then excreted as the major urinary metabolite. Following oral administration of 200 mg of 14C-bupropion in humans, 87% and 10% of the radioactive dose were recovered in the urine and feces, respectively. However, the fraction of the oral dose of bupropion excreted unchanged was only 0.5%, a finding consistent with the extensive metabolism of bupropion. •Route of elimination (Drug B): The elimination of methadone is mediated by extensive biotransformation, followed by renal and fecal excretion. Unmetabolized methadone and its metabolites are excreted in urine to a variable degree. •Half-life (Drug A): 24 hours •Half-life (Drug B): Due to interindividual differences in pharmacokinetics, estimates of methadone's half-life have ranged from 15–207 hours with official monographs listing it between 7-59 hours. •Clearance (Drug A): No clearance available •Clearance (Drug B): Due to interindividual differences in pharmacokinetics, estimates of methadone's clearance have ranged from 5.9–13 L/h hours with approved monographs listing it between 1.4 to 126 L/h. •Toxicity (Drug A): Symptoms of overdose include seizures, hallucinations, loss of consciousness, tachycardia, and cardiac arrest. •Toxicity (Drug B): In severe overdosage, particularly by the intravenous route, apnea, circulatory collapse, cardiac arrest, and death may occur. •Brand Names (Drug A): Aplenzin, Auvelity, Budeprion, Contrave, Forfivo, Wellbutrin, Zyban •Brand Names (Drug B): Diskets, Dolophine, Metadol, Metadol-D, Methadose •Synonyms (Drug A): No synonyms listed •Synonyms (Drug B): Metadona Methadone Methadonum •Summary (Drug A): Bupropion is a norepinephrine and dopamine reuptake inhibitor used in the treatment of major depressive disorder (MDD), seasonal affective disorder (SAD), and as an aid to smoking cessation. •Summary (Drug B): Methadone is an opioid analgesic indicated for management of severe pain that is not responsive to alternative treatments. Also used to aid in detoxification and maintenance treatment of opioid addiction. Output: The concomitant administration of CNS depressants with methadone may produce an increase in respiratory depression, profound sedation, hypotension, coma, and other adverse effects. The severity of the interaction is major.

Does Bupropion and Methazolamide interact?

•Drug A: Bupropion •Drug B: Methazolamide •Severity: MODERATE •Description: Methazolamide may increase the excretion rate of Bupropion which could result in a lower serum level and potentially a reduction in efficacy. •Extended Description: The subject drug induces diuresis1,2, which can theoretically increase the excretion rate of the affected drug, which is eliminated by the kidneys. Additionally, it could affect renal tubular reabsorption of certain drugs. Exposure to the affected drug can be markedly reduced, leading to subtherapeutic drug levels that are unlikely to elicit an adequate clinical response. •Indication (Drug A): Bupropion is indicated for the treatment of major depressive disorder (MDD), seasonal affective disorder (SAD), and as an aid to smoking cessation. When used in combination with naltrexone as the marketed product ContraveⓇ, bupropion is indicated as an adjunct to a reduced-calorie diet and increased physical activity for chronic weight management in adults with an initial body mass index (BMI) of: 30 kg/m^2 or greater (obese) or 27 kg/m^2 or greater (overweight) in the presence of at least one weight-related comorbid condition (e.g., hypertension, type 2 diabetes mellitus, or dyslipidemia). Bupropion is also used off-label as a first-line treatment in patients with ADHD and comorbid bipolar disorder when used as an adjunct to mood stabilizers. •Indication (Drug B): For treatment of chronic open-angle glaucoma and acute angle-closure glaucoma •Pharmacodynamics (Drug A): Bupropion is chemically unrelated to tricyclic, tetracyclic, selective serotonin re-uptake inhibitors, or other known antidepressant agents. Compared to classical tricyclic antidepressants, Bupropion is a relatively weak inhibitor of the neuronal uptake of norepinephrine and dopamine. In addition, Bupropion does not inhibit monoamine oxidase. Bupropion has been found to be essentially inactive at the serotonin transporter (SERT)(IC50 >10 000 nM), however both bupropion and its primary metabolite hydroxybupropion have been found to block the function of cation-selective serotonin type 3A receptors (5-HT3ARs). Bupropion produces dose-related central nervous system (CNS) stimulant effects in animals, as evidenced by increased locomotor activity, increased rates of responding in various schedule-controlled operant behaviour tasks, and, at high doses, induction of mild stereotyped behaviour. Due to these stimulant effects and selective activity at dopamine and norepinephrine receptors, bupropion has been identified as having an abuse potential. Bupropion has a similar structure to the controlled substance Cathinone, and has been identified as having mild amphetamine-like activity, particularly when inhaled or injected. Bupropion is also known to lower the seizure threshold, making any pre-existing seizure conditions a contraindication to its use. This risk is exacerbated when bupropion is combined with other drugs or substances that lower the seizure threshold, such as cocaine, or in clinical situations that would increase the risk of a seizure such as abrupt alcohol or benzodiazepine withdrawal. As norepinephrine has been shown to have anticonvulsant properties, bupropion's inhibitory effects on NET are thought to contribute to its pro-convulsant activity. Bupropion has been shown to increase blood pressure and pose a risk for exacerbation of unmanaged or pre-existing hypertension, however, clinical trials of bupropion in smokers with CVD have not identified an increased incidence of CV events including stroke or heart attack. In clinical trials, the mean increase in systolic blood pressure associated with the use of bupropion was found to be 1.3 mmHg. •Pharmacodynamics (Drug B): Methazolamide is topical carbonic anhydrase inhibitor. Methazolamide is indicated for the reduction of elevated intraocular pressure in patients with open-angle glaucoma or ocular hypertension who are insufficiently responsive to beta-blockers. Methazolamide is a sulfonamide derivative; however, it does not have any clinically significant antimicrobial properties. Although methazolamide achieves a high concentration in the cerebrospinal fluid, it is not-considered an effective anticonvulsant. Methazolamide has a weak and transient diuretic effect, therefore use results in an increase in urinary volume, with excretion of sodium, potassium and chloride. •Mechanism of action (Drug A): Bupropion is a norepinephrine/dopamine-reuptake inhibitor (NDRI) that exerts its pharmacological effects by weakly inhibiting the enzymes involved in the uptake of the neurotransmitters norepinephrine and dopamine from the synaptic cleft, therefore prolonging their duration of action within the neuronal synapse and the downstream effects of these neurotransmitters. More specifically, bupropion binds to the norepinephrine transporter (NET) and the dopamine transporter (DAT). Bupropion was originally classified as an "atypical" antidepressant because it does not exert the same effects as the classical antidepressants such as Monoamine Oxidase Inhibitors (MAOIs), Tricyclic Antidepressants (TCAs), or Selective Serotonin Reuptake Inhibitors (SSRIs). While it has comparable effectiveness to typical first-line options for the treatment of depression such as SSRIs, bupropion is a unique option for the treatment of MDD as it lacks any clinically relevant serotonergic effects, typical of other mood medications, or any effects on histamine or adrenaline receptors. Lack of activity at these receptors results in a more tolerable side effect profile; bupropion is less likely to cause sexual side effects, sedation, or weight gain as compared to SSRIs or TCAs, for example. When used as an aid to smoking cessation, bupropion is thought to confer its anti-craving and anti-withdrawal effects by inhibiting dopamine reuptake, which is thought to be involved in the reward pathways associated with nicotine, and through the antagonism of the nicotinic acetylcholinergic receptor (AChR), thereby blunting the effects of nicotine. Furthermore, the stimulatory effects produced by bupropion in the central nervous system are similar to nicotine's effects, making low doses of bupropion a suitable option as a nicotine substitute. When used in combination with naltrexone in the marketed product ContraveⓇ for chronic weight management, the two components are thought to have effects on areas of the brain involved in the regulation of food intake. This includes the hypothalamus, which is involved in appetite regulation, and the mesolimbic dopamine circuit, which is involved in reward pathways. Studies have shown that the combined activity of bupropion and naltrexone increase the firing rate of hypothalamic pro-opiomelanocortin (POMC) neurons and blockade of opioid receptor-mediated POMC auto-inhibition, which are associated with a reduction in food intake and increased energy expenditure. This combination was also found to reduce food intake when injected directly into the ventral tegmental area of the mesolimbic circuit in mice, which is an area associated with the regulation of reward pathways. •Mechanism of action (Drug B): Methazolamide is a potent inhibitor of carbonic anhydrase. Inhibition of carbonic anhydrase in the ciliary processes of the eye decreases aqueous humor secretion, presumably by slowing the formation of bicarbonate ions with subsequent reduction in sodium and fluid transport. •Absorption (Drug A): Bupropion is currently available in 3 distinct, but bioequivalent formulations: immediate release (IR), sustained-release (SR), and extended-release (XL). Immediate Release Formulation In humans, following oral administration of bupropion hydrochloride tablets, peak plasma bupropion concentrations are usually achieved within 2 hours. IR formulations provide a short duration of action and are therefore generally dosed three times per day. Sustained Release Formulation In humans, following oral administration of bupropion hydrochloride sustained-release tablets (SR), peak plasma concentration (Cmax) of bupropion is usually achieved within 3 hours. SR formulations provide a 12-hour extended release of medication and are therefore generally dosed twice per day. Extended Release Formulation Following single oral administration of bupropion hydrochloride extended-release tablets (XL) to healthy volunteers, the median time to peak plasma concentrations for bupropion was approximately 5 hours. The presence of food did not affect the peak concentration or area under the curve of bupropion. XL formulations provide a 24-hour extended release of medication and are therefore generally dosed once per day/ In a trial comparing chronic dosing with bupropion hydrochloride extended-release tablets (SR) 150 mg twice daily to bupropion immediate-release formulation 100 mg 3 times daily, the steady state Cmax for bupropion after bupropion hydrochloride sustained-release tablets (SR) administration was approximately 85% of those achieved after bupropion immediate-release formulation administration. Exposure (AUC) to bupropion was equivalent for both formulations. Bioequivalence was also demonstrated for all three major active metabolites (i.e., hydroxybupropion, threohydrobupropion and erythrohydrobupropion) for both Cmax and AUC. Thus, at steady state, bupropion hydrochloride sustained-release tablets (SR) given twice daily, and the immediate-release formulation of bupropion given 3 times daily, are essentially bioequivalent for both bupropion and the 3 quantitatively important metabolites. Furthermore, in a study comparing 14-day dosing with bupropion hydrochloride extended-release tablets (XL), 300 mg once-daily to the immediate-release formulation of bupropion at 100 mg 3 times daily, equivalence was demonstrated for peak plasma concentration and area under the curve for bupropion and the three metabolites (hydroxybupropion, threohydrobupropion, and erythrohydrobupropion). Additionally, in a study comparing 14-day dosing with bupropion hydrochloride extended-release tablets (XL) 300 mg once daily to the sustained-release formulation of bupropion at 150 mg 2 times daily, equivalence was demonstrated for peak plasma concentration and area under the curve for bupropion and the three metabolites. Bupropion hydrochloride extended-release tablets (SR) can be taken with or without food. Bupropion Cmax and AUC were increased by 11% to 35% and 16% to 19%, respectively, when bupropion hydrochloride extended-release tablets (SR) was administered with food to healthy volunteers in three trials. The food effect is not considered clinically significant. Following a single-dose administration of bupropion hydrochloride extended-release tablets (SR) in humans, Cmax of bupropion's metabolite hydroxybupropion occurs approximately 6 hours post-dose and is approximately 10 times the peak level of the parent drug at steady state. The elimination half-life of hydroxybupropion is approximately 20 (±5) hours and its AUC at steady state is about 17 times that of bupropion. The times to peak concentrations for the erythrohydrobupropion and threohydrobupropion metabolites are similar to that of the hydroxybupropion metabolite. However, their elimination half-lives are longer, 33(±10) and 37 (±13) hours, respectively, and steady-state AUCs are 1.5 and 7 times that of bupropion, respectively. •Absorption (Drug B): Methazolamide is well absorbed from the gastrointestinal tract. •Volume of distribution (Drug A): No volume of distribution available •Volume of distribution (Drug B): 17 to 23 L •Protein binding (Drug A): In vitro tests show that bupropion is 84% bound to human plasma proteins at concentrations up to 200 mcg per mL. The extent of protein binding of the hydroxybupropion metabolite is similar to that for bupropion, whereas the extent of protein binding of the threohydrobupropion metabolite is about half that seen with bupropion. •Protein binding (Drug B): 55% •Metabolism (Drug A): Bupropion is extensively metabolized in humans. Three metabolites are active: hydroxybupropion, which is formed via hydroxylation of the tert-butyl group of bupropion, and the amino-alcohol isomers, threohydrobupropion and erythrohydrobupropion, which are formed via reduction of the carbonyl group. In vitro findings suggest that CYP2B6 is the principal isoenzyme involved in the formation of hydroxybupropion, while cytochrome P450 enzymes are not involved in the formation of threohydrobupropion. Hydroxybupropion has been shown to have the same affinity as bupropion for the norepinephrine transporter (NET) but approximately 50% of its antidepressant activity despite reaching concentrations of ~10-fold higher than that of the parent drug. Oxidation of the bupropion side chain results in the formation of a glycine conjugate of meta-chlorobenzoic acid, which is then excreted as the major urinary metabolite. The potency and toxicity of the metabolites relative to bupropion have not been fully characterized. However, it has been demonstrated in an antidepressant screening test in mice that hydroxybupropion is one-half as potent as bupropion, while threohydrobupropion and erythrohydrobupropion are 5-fold less potent than bupropion. This may be of clinical importance because the plasma concentrations of the metabolites are as high as or higher than those of bupropion. Bupropion and its metabolites exhibit linear kinetics following chronic administration of 300 to 450 mg per day. •Metabolism (Drug B): No metabolism available •Route of elimination (Drug A): Bupropion is extensively metabolized in humans. Oxidation of the bupropion side chain results in the formation of a glycine conjugate of metachlorobenzoic acid, which is then excreted as the major urinary metabolite. Following oral administration of 200 mg of 14C-bupropion in humans, 87% and 10% of the radioactive dose were recovered in the urine and feces, respectively. However, the fraction of the oral dose of bupropion excreted unchanged was only 0.5%, a finding consistent with the extensive metabolism of bupropion. •Route of elimination (Drug B): No route of elimination available •Half-life (Drug A): 24 hours •Half-life (Drug B): 14 hours •Clearance (Drug A): No clearance available •Clearance (Drug B): No clearance available •Toxicity (Drug A): Symptoms of overdose include seizures, hallucinations, loss of consciousness, tachycardia, and cardiac arrest. •Toxicity (Drug B): Electrolyte imbalance, development of an acidotic state, and central nervous system effects might be expected to occur in the case of an overdose. •Brand Names (Drug A): Aplenzin, Auvelity, Budeprion, Contrave, Forfivo, Wellbutrin, Zyban •Brand Names (Drug B): No brand names available •Synonyms (Drug A): No synonyms listed •Synonyms (Drug B): No synonyms listed •Summary (Drug A): Bupropion is a norepinephrine and dopamine reuptake inhibitor used in the treatment of major depressive disorder (MDD), seasonal affective disorder (SAD), and as an aid to smoking cessation. •Summary (Drug B): Methazolamide is a carbonic anhydrase inhibitor used to treat open angle glaucoma and acute angle closure glaucoma.

The subject drug induces diuresis1,2, which can theoretically increase the excretion rate of the affected drug, which is eliminated by the kidneys. Additionally, it could affect renal tubular reabsorption of certain drugs. Exposure to the affected drug can be markedly reduced, leading to subtherapeutic drug levels that are unlikely to elicit an adequate clinical response. The severity of the interaction is moderate.

Question: Does Bupropion and Methazolamide interact? Information: •Drug A: Bupropion •Drug B: Methazolamide •Severity: MODERATE •Description: Methazolamide may increase the excretion rate of Bupropion which could result in a lower serum level and potentially a reduction in efficacy. •Extended Description: The subject drug induces diuresis1,2, which can theoretically increase the excretion rate of the affected drug, which is eliminated by the kidneys. Additionally, it could affect renal tubular reabsorption of certain drugs. Exposure to the affected drug can be markedly reduced, leading to subtherapeutic drug levels that are unlikely to elicit an adequate clinical response. •Indication (Drug A): Bupropion is indicated for the treatment of major depressive disorder (MDD), seasonal affective disorder (SAD), and as an aid to smoking cessation. When used in combination with naltrexone as the marketed product ContraveⓇ, bupropion is indicated as an adjunct to a reduced-calorie diet and increased physical activity for chronic weight management in adults with an initial body mass index (BMI) of: 30 kg/m^2 or greater (obese) or 27 kg/m^2 or greater (overweight) in the presence of at least one weight-related comorbid condition (e.g., hypertension, type 2 diabetes mellitus, or dyslipidemia). Bupropion is also used off-label as a first-line treatment in patients with ADHD and comorbid bipolar disorder when used as an adjunct to mood stabilizers. •Indication (Drug B): For treatment of chronic open-angle glaucoma and acute angle-closure glaucoma •Pharmacodynamics (Drug A): Bupropion is chemically unrelated to tricyclic, tetracyclic, selective serotonin re-uptake inhibitors, or other known antidepressant agents. Compared to classical tricyclic antidepressants, Bupropion is a relatively weak inhibitor of the neuronal uptake of norepinephrine and dopamine. In addition, Bupropion does not inhibit monoamine oxidase. Bupropion has been found to be essentially inactive at the serotonin transporter (SERT)(IC50 >10 000 nM), however both bupropion and its primary metabolite hydroxybupropion have been found to block the function of cation-selective serotonin type 3A receptors (5-HT3ARs). Bupropion produces dose-related central nervous system (CNS) stimulant effects in animals, as evidenced by increased locomotor activity, increased rates of responding in various schedule-controlled operant behaviour tasks, and, at high doses, induction of mild stereotyped behaviour. Due to these stimulant effects and selective activity at dopamine and norepinephrine receptors, bupropion has been identified as having an abuse potential. Bupropion has a similar structure to the controlled substance Cathinone, and has been identified as having mild amphetamine-like activity, particularly when inhaled or injected. Bupropion is also known to lower the seizure threshold, making any pre-existing seizure conditions a contraindication to its use. This risk is exacerbated when bupropion is combined with other drugs or substances that lower the seizure threshold, such as cocaine, or in clinical situations that would increase the risk of a seizure such as abrupt alcohol or benzodiazepine withdrawal. As norepinephrine has been shown to have anticonvulsant properties, bupropion's inhibitory effects on NET are thought to contribute to its pro-convulsant activity. Bupropion has been shown to increase blood pressure and pose a risk for exacerbation of unmanaged or pre-existing hypertension, however, clinical trials of bupropion in smokers with CVD have not identified an increased incidence of CV events including stroke or heart attack. In clinical trials, the mean increase in systolic blood pressure associated with the use of bupropion was found to be 1.3 mmHg. •Pharmacodynamics (Drug B): Methazolamide is topical carbonic anhydrase inhibitor. Methazolamide is indicated for the reduction of elevated intraocular pressure in patients with open-angle glaucoma or ocular hypertension who are insufficiently responsive to beta-blockers. Methazolamide is a sulfonamide derivative; however, it does not have any clinically significant antimicrobial properties. Although methazolamide achieves a high concentration in the cerebrospinal fluid, it is not-considered an effective anticonvulsant. Methazolamide has a weak and transient diuretic effect, therefore use results in an increase in urinary volume, with excretion of sodium, potassium and chloride. •Mechanism of action (Drug A): Bupropion is a norepinephrine/dopamine-reuptake inhibitor (NDRI) that exerts its pharmacological effects by weakly inhibiting the enzymes involved in the uptake of the neurotransmitters norepinephrine and dopamine from the synaptic cleft, therefore prolonging their duration of action within the neuronal synapse and the downstream effects of these neurotransmitters. More specifically, bupropion binds to the norepinephrine transporter (NET) and the dopamine transporter (DAT). Bupropion was originally classified as an "atypical" antidepressant because it does not exert the same effects as the classical antidepressants such as Monoamine Oxidase Inhibitors (MAOIs), Tricyclic Antidepressants (TCAs), or Selective Serotonin Reuptake Inhibitors (SSRIs). While it has comparable effectiveness to typical first-line options for the treatment of depression such as SSRIs, bupropion is a unique option for the treatment of MDD as it lacks any clinically relevant serotonergic effects, typical of other mood medications, or any effects on histamine or adrenaline receptors. Lack of activity at these receptors results in a more tolerable side effect profile; bupropion is less likely to cause sexual side effects, sedation, or weight gain as compared to SSRIs or TCAs, for example. When used as an aid to smoking cessation, bupropion is thought to confer its anti-craving and anti-withdrawal effects by inhibiting dopamine reuptake, which is thought to be involved in the reward pathways associated with nicotine, and through the antagonism of the nicotinic acetylcholinergic receptor (AChR), thereby blunting the effects of nicotine. Furthermore, the stimulatory effects produced by bupropion in the central nervous system are similar to nicotine's effects, making low doses of bupropion a suitable option as a nicotine substitute. When used in combination with naltrexone in the marketed product ContraveⓇ for chronic weight management, the two components are thought to have effects on areas of the brain involved in the regulation of food intake. This includes the hypothalamus, which is involved in appetite regulation, and the mesolimbic dopamine circuit, which is involved in reward pathways. Studies have shown that the combined activity of bupropion and naltrexone increase the firing rate of hypothalamic pro-opiomelanocortin (POMC) neurons and blockade of opioid receptor-mediated POMC auto-inhibition, which are associated with a reduction in food intake and increased energy expenditure. This combination was also found to reduce food intake when injected directly into the ventral tegmental area of the mesolimbic circuit in mice, which is an area associated with the regulation of reward pathways. •Mechanism of action (Drug B): Methazolamide is a potent inhibitor of carbonic anhydrase. Inhibition of carbonic anhydrase in the ciliary processes of the eye decreases aqueous humor secretion, presumably by slowing the formation of bicarbonate ions with subsequent reduction in sodium and fluid transport. •Absorption (Drug A): Bupropion is currently available in 3 distinct, but bioequivalent formulations: immediate release (IR), sustained-release (SR), and extended-release (XL). Immediate Release Formulation In humans, following oral administration of bupropion hydrochloride tablets, peak plasma bupropion concentrations are usually achieved within 2 hours. IR formulations provide a short duration of action and are therefore generally dosed three times per day. Sustained Release Formulation In humans, following oral administration of bupropion hydrochloride sustained-release tablets (SR), peak plasma concentration (Cmax) of bupropion is usually achieved within 3 hours. SR formulations provide a 12-hour extended release of medication and are therefore generally dosed twice per day. Extended Release Formulation Following single oral administration of bupropion hydrochloride extended-release tablets (XL) to healthy volunteers, the median time to peak plasma concentrations for bupropion was approximately 5 hours. The presence of food did not affect the peak concentration or area under the curve of bupropion. XL formulations provide a 24-hour extended release of medication and are therefore generally dosed once per day/ In a trial comparing chronic dosing with bupropion hydrochloride extended-release tablets (SR) 150 mg twice daily to bupropion immediate-release formulation 100 mg 3 times daily, the steady state Cmax for bupropion after bupropion hydrochloride sustained-release tablets (SR) administration was approximately 85% of those achieved after bupropion immediate-release formulation administration. Exposure (AUC) to bupropion was equivalent for both formulations. Bioequivalence was also demonstrated for all three major active metabolites (i.e., hydroxybupropion, threohydrobupropion and erythrohydrobupropion) for both Cmax and AUC. Thus, at steady state, bupropion hydrochloride sustained-release tablets (SR) given twice daily, and the immediate-release formulation of bupropion given 3 times daily, are essentially bioequivalent for both bupropion and the 3 quantitatively important metabolites. Furthermore, in a study comparing 14-day dosing with bupropion hydrochloride extended-release tablets (XL), 300 mg once-daily to the immediate-release formulation of bupropion at 100 mg 3 times daily, equivalence was demonstrated for peak plasma concentration and area under the curve for bupropion and the three metabolites (hydroxybupropion, threohydrobupropion, and erythrohydrobupropion). Additionally, in a study comparing 14-day dosing with bupropion hydrochloride extended-release tablets (XL) 300 mg once daily to the sustained-release formulation of bupropion at 150 mg 2 times daily, equivalence was demonstrated for peak plasma concentration and area under the curve for bupropion and the three metabolites. Bupropion hydrochloride extended-release tablets (SR) can be taken with or without food. Bupropion Cmax and AUC were increased by 11% to 35% and 16% to 19%, respectively, when bupropion hydrochloride extended-release tablets (SR) was administered with food to healthy volunteers in three trials. The food effect is not considered clinically significant. Following a single-dose administration of bupropion hydrochloride extended-release tablets (SR) in humans, Cmax of bupropion's metabolite hydroxybupropion occurs approximately 6 hours post-dose and is approximately 10 times the peak level of the parent drug at steady state. The elimination half-life of hydroxybupropion is approximately 20 (±5) hours and its AUC at steady state is about 17 times that of bupropion. The times to peak concentrations for the erythrohydrobupropion and threohydrobupropion metabolites are similar to that of the hydroxybupropion metabolite. However, their elimination half-lives are longer, 33(±10) and 37 (±13) hours, respectively, and steady-state AUCs are 1.5 and 7 times that of bupropion, respectively. •Absorption (Drug B): Methazolamide is well absorbed from the gastrointestinal tract. •Volume of distribution (Drug A): No volume of distribution available •Volume of distribution (Drug B): 17 to 23 L •Protein binding (Drug A): In vitro tests show that bupropion is 84% bound to human plasma proteins at concentrations up to 200 mcg per mL. The extent of protein binding of the hydroxybupropion metabolite is similar to that for bupropion, whereas the extent of protein binding of the threohydrobupropion metabolite is about half that seen with bupropion. •Protein binding (Drug B): 55% •Metabolism (Drug A): Bupropion is extensively metabolized in humans. Three metabolites are active: hydroxybupropion, which is formed via hydroxylation of the tert-butyl group of bupropion, and the amino-alcohol isomers, threohydrobupropion and erythrohydrobupropion, which are formed via reduction of the carbonyl group. In vitro findings suggest that CYP2B6 is the principal isoenzyme involved in the formation of hydroxybupropion, while cytochrome P450 enzymes are not involved in the formation of threohydrobupropion. Hydroxybupropion has been shown to have the same affinity as bupropion for the norepinephrine transporter (NET) but approximately 50% of its antidepressant activity despite reaching concentrations of ~10-fold higher than that of the parent drug. Oxidation of the bupropion side chain results in the formation of a glycine conjugate of meta-chlorobenzoic acid, which is then excreted as the major urinary metabolite. The potency and toxicity of the metabolites relative to bupropion have not been fully characterized. However, it has been demonstrated in an antidepressant screening test in mice that hydroxybupropion is one-half as potent as bupropion, while threohydrobupropion and erythrohydrobupropion are 5-fold less potent than bupropion. This may be of clinical importance because the plasma concentrations of the metabolites are as high as or higher than those of bupropion. Bupropion and its metabolites exhibit linear kinetics following chronic administration of 300 to 450 mg per day. •Metabolism (Drug B): No metabolism available •Route of elimination (Drug A): Bupropion is extensively metabolized in humans. Oxidation of the bupropion side chain results in the formation of a glycine conjugate of metachlorobenzoic acid, which is then excreted as the major urinary metabolite. Following oral administration of 200 mg of 14C-bupropion in humans, 87% and 10% of the radioactive dose were recovered in the urine and feces, respectively. However, the fraction of the oral dose of bupropion excreted unchanged was only 0.5%, a finding consistent with the extensive metabolism of bupropion. •Route of elimination (Drug B): No route of elimination available •Half-life (Drug A): 24 hours •Half-life (Drug B): 14 hours •Clearance (Drug A): No clearance available •Clearance (Drug B): No clearance available •Toxicity (Drug A): Symptoms of overdose include seizures, hallucinations, loss of consciousness, tachycardia, and cardiac arrest. •Toxicity (Drug B): Electrolyte imbalance, development of an acidotic state, and central nervous system effects might be expected to occur in the case of an overdose. •Brand Names (Drug A): Aplenzin, Auvelity, Budeprion, Contrave, Forfivo, Wellbutrin, Zyban •Brand Names (Drug B): No brand names available •Synonyms (Drug A): No synonyms listed •Synonyms (Drug B): No synonyms listed •Summary (Drug A): Bupropion is a norepinephrine and dopamine reuptake inhibitor used in the treatment of major depressive disorder (MDD), seasonal affective disorder (SAD), and as an aid to smoking cessation. •Summary (Drug B): Methazolamide is a carbonic anhydrase inhibitor used to treat open angle glaucoma and acute angle closure glaucoma. Output: The subject drug induces diuresis1,2, which can theoretically increase the excretion rate of the affected drug, which is eliminated by the kidneys. Additionally, it could affect renal tubular reabsorption of certain drugs. Exposure to the affected drug can be markedly reduced, leading to subtherapeutic drug levels that are unlikely to elicit an adequate clinical response. The severity of the interaction is moderate.

Does Bupropion and Methimazole interact?

•Drug A: Bupropion •Drug B: Methimazole •Severity: MINOR •Description: The serum concentration of Bupropion can be increased when it is combined with Methimazole. •Extended Description: Bupropion is extensively metabolized to hydroxybupropion by CYP2B6. •Indication (Drug A): Bupropion is indicated for the treatment of major depressive disorder (MDD), seasonal affective disorder (SAD), and as an aid to smoking cessation. When used in combination with naltrexone as the marketed product ContraveⓇ, bupropion is indicated as an adjunct to a reduced-calorie diet and increased physical activity for chronic weight management in adults with an initial body mass index (BMI) of: 30 kg/m^2 or greater (obese) or 27 kg/m^2 or greater (overweight) in the presence of at least one weight-related comorbid condition (e.g., hypertension, type 2 diabetes mellitus, or dyslipidemia). Bupropion is also used off-label as a first-line treatment in patients with ADHD and comorbid bipolar disorder when used as an adjunct to mood stabilizers. •Indication (Drug B): In the United States, methimazole is indicated for the treatment of hyperthyroidism in patients with Graves' disease or toxic multinodular goiter for whom thyroidectomy or radioactive iodine therapy are not appropriate treatment options. Methimazole is also indicated for the amelioration of hyperthyroid symptoms in preparation for thyroidectomy or radioactive iodine therapy. In Canada, methimazole carries the above indications and is also indicated for the medical treatment of hyperthyroidism regardless of other available treatment options. •Pharmacodynamics (Drug A): Bupropion is chemically unrelated to tricyclic, tetracyclic, selective serotonin re-uptake inhibitors, or other known antidepressant agents. Compared to classical tricyclic antidepressants, Bupropion is a relatively weak inhibitor of the neuronal uptake of norepinephrine and dopamine. In addition, Bupropion does not inhibit monoamine oxidase. Bupropion has been found to be essentially inactive at the serotonin transporter (SERT)(IC50 >10 000 nM), however both bupropion and its primary metabolite hydroxybupropion have been found to block the function of cation-selective serotonin type 3A receptors (5-HT3ARs). Bupropion produces dose-related central nervous system (CNS) stimulant effects in animals, as evidenced by increased locomotor activity, increased rates of responding in various schedule-controlled operant behaviour tasks, and, at high doses, induction of mild stereotyped behaviour. Due to these stimulant effects and selective activity at dopamine and norepinephrine receptors, bupropion has been identified as having an abuse potential. Bupropion has a similar structure to the controlled substance Cathinone, and has been identified as having mild amphetamine-like activity, particularly when inhaled or injected. Bupropion is also known to lower the seizure threshold, making any pre-existing seizure conditions a contraindication to its use. This risk is exacerbated when bupropion is combined with other drugs or substances that lower the seizure threshold, such as cocaine, or in clinical situations that would increase the risk of a seizure such as abrupt alcohol or benzodiazepine withdrawal. As norepinephrine has been shown to have anticonvulsant properties, bupropion's inhibitory effects on NET are thought to contribute to its pro-convulsant activity. Bupropion has been shown to increase blood pressure and pose a risk for exacerbation of unmanaged or pre-existing hypertension, however, clinical trials of bupropion in smokers with CVD have not identified an increased incidence of CV events including stroke or heart attack. In clinical trials, the mean increase in systolic blood pressure associated with the use of bupropion was found to be 1.3 mmHg. •Pharmacodynamics (Drug B): Methimazole inhibits the synthesis of thyroid hormones resulting in an alleviation of hyperthyroidism. Onset of action occurs within 12 to 18 hours, and its duration of action is 36 to 72 hours, likely due to concentration of methimazole and some metabolites within the thyroid gland after administration. The most serious potential side effect of methimazole therapy is agranulocytosis, and patients should be instructed to monitor for, and report, any signs or symptoms of agranulocytosis such as fever or sore throat. Other cytopenias may also occur during methimazole therapy. There also exists the potential for severe hepatic toxicity with the use of methimazole, and monitoring for signs and symptoms of hepatic dysfunction, such as jaundice, anorexia, pruritus, and elevation in liver transaminases, is prudent in patients using this therapy. •Mechanism of action (Drug A): Bupropion is a norepinephrine/dopamine-reuptake inhibitor (NDRI) that exerts its pharmacological effects by weakly inhibiting the enzymes involved in the uptake of the neurotransmitters norepinephrine and dopamine from the synaptic cleft, therefore prolonging their duration of action within the neuronal synapse and the downstream effects of these neurotransmitters. More specifically, bupropion binds to the norepinephrine transporter (NET) and the dopamine transporter (DAT). Bupropion was originally classified as an "atypical" antidepressant because it does not exert the same effects as the classical antidepressants such as Monoamine Oxidase Inhibitors (MAOIs), Tricyclic Antidepressants (TCAs), or Selective Serotonin Reuptake Inhibitors (SSRIs). While it has comparable effectiveness to typical first-line options for the treatment of depression such as SSRIs, bupropion is a unique option for the treatment of MDD as it lacks any clinically relevant serotonergic effects, typical of other mood medications, or any effects on histamine or adrenaline receptors. Lack of activity at these receptors results in a more tolerable side effect profile; bupropion is less likely to cause sexual side effects, sedation, or weight gain as compared to SSRIs or TCAs, for example. When used as an aid to smoking cessation, bupropion is thought to confer its anti-craving and anti-withdrawal effects by inhibiting dopamine reuptake, which is thought to be involved in the reward pathways associated with nicotine, and through the antagonism of the nicotinic acetylcholinergic receptor (AChR), thereby blunting the effects of nicotine. Furthermore, the stimulatory effects produced by bupropion in the central nervous system are similar to nicotine's effects, making low doses of bupropion a suitable option as a nicotine substitute. When used in combination with naltrexone in the marketed product ContraveⓇ for chronic weight management, the two components are thought to have effects on areas of the brain involved in the regulation of food intake. This includes the hypothalamus, which is involved in appetite regulation, and the mesolimbic dopamine circuit, which is involved in reward pathways. Studies have shown that the combined activity of bupropion and naltrexone increase the firing rate of hypothalamic pro-opiomelanocortin (POMC) neurons and blockade of opioid receptor-mediated POMC auto-inhibition, which are associated with a reduction in food intake and increased energy expenditure. This combination was also found to reduce food intake when injected directly into the ventral tegmental area of the mesolimbic circuit in mice, which is an area associated with the regulation of reward pathways. •Mechanism of action (Drug B): Methimazole's primary mechanism of action appears to be interference in an early step in thyroid hormone synthesis involving thyroid peroxidase (TPO), however the exact method through which methimazole inhibits this step is unclear. TPO, along with hydrogen peroxide, normally catalyzes the conversion of iodide to iodine and then further catalyzes the incorporation of this iodine onto the 3 and/or 5 positions of the phenol rings of tyrosine residues in thyroglobulin. These thyroglobulin molecules then degrade within thyroid follicular cells to form either thyroxine (T 4 ) or tri-iodothyronine (T 3 ), which are the main hormones produced by the thyroid gland. Methimazole may directly inhibit TPO, but has been shown in vivo to instead act as a competitive substrate for TPO, thus becoming iodinated itself and interfering with the iodination of thyroglobulin. Another proposed theory is that methimazole’s sulfur moiety may interact directly with the iron atom at the centre of TPO’s heme molecule, thus inhibiting its ability to iodinate tyrosine residues. Other proposed mechanisms with weaker evidence include methimazole binding directly to thyroglobulin or direct inhibition of thyroglobulin itself. •Absorption (Drug A): Bupropion is currently available in 3 distinct, but bioequivalent formulations: immediate release (IR), sustained-release (SR), and extended-release (XL). Immediate Release Formulation In humans, following oral administration of bupropion hydrochloride tablets, peak plasma bupropion concentrations are usually achieved within 2 hours. IR formulations provide a short duration of action and are therefore generally dosed three times per day. Sustained Release Formulation In humans, following oral administration of bupropion hydrochloride sustained-release tablets (SR), peak plasma concentration (Cmax) of bupropion is usually achieved within 3 hours. SR formulations provide a 12-hour extended release of medication and are therefore generally dosed twice per day. Extended Release Formulation Following single oral administration of bupropion hydrochloride extended-release tablets (XL) to healthy volunteers, the median time to peak plasma concentrations for bupropion was approximately 5 hours. The presence of food did not affect the peak concentration or area under the curve of bupropion. XL formulations provide a 24-hour extended release of medication and are therefore generally dosed once per day/ In a trial comparing chronic dosing with bupropion hydrochloride extended-release tablets (SR) 150 mg twice daily to bupropion immediate-release formulation 100 mg 3 times daily, the steady state Cmax for bupropion after bupropion hydrochloride sustained-release tablets (SR) administration was approximately 85% of those achieved after bupropion immediate-release formulation administration. Exposure (AUC) to bupropion was equivalent for both formulations. Bioequivalence was also demonstrated for all three major active metabolites (i.e., hydroxybupropion, threohydrobupropion and erythrohydrobupropion) for both Cmax and AUC. Thus, at steady state, bupropion hydrochloride sustained-release tablets (SR) given twice daily, and the immediate-release formulation of bupropion given 3 times daily, are essentially bioequivalent for both bupropion and the 3 quantitatively important metabolites. Furthermore, in a study comparing 14-day dosing with bupropion hydrochloride extended-release tablets (XL), 300 mg once-daily to the immediate-release formulation of bupropion at 100 mg 3 times daily, equivalence was demonstrated for peak plasma concentration and area under the curve for bupropion and the three metabolites (hydroxybupropion, threohydrobupropion, and erythrohydrobupropion). Additionally, in a study comparing 14-day dosing with bupropion hydrochloride extended-release tablets (XL) 300 mg once daily to the sustained-release formulation of bupropion at 150 mg 2 times daily, equivalence was demonstrated for peak plasma concentration and area under the curve for bupropion and the three metabolites. Bupropion hydrochloride extended-release tablets (SR) can be taken with or without food. Bupropion Cmax and AUC were increased by 11% to 35% and 16% to 19%, respectively, when bupropion hydrochloride extended-release tablets (SR) was administered with food to healthy volunteers in three trials. The food effect is not considered clinically significant. Following a single-dose administration of bupropion hydrochloride extended-release tablets (SR) in humans, Cmax of bupropion's metabolite hydroxybupropion occurs approximately 6 hours post-dose and is approximately 10 times the peak level of the parent drug at steady state. The elimination half-life of hydroxybupropion is approximately 20 (±5) hours and its AUC at steady state is about 17 times that of bupropion. The times to peak concentrations for the erythrohydrobupropion and threohydrobupropion metabolites are similar to that of the hydroxybupropion metabolite. However, their elimination half-lives are longer, 33(±10) and 37 (±13) hours, respectively, and steady-state AUCs are 1.5 and 7 times that of bupropion, respectively. •Absorption (Drug B): Absorption of methimazole after oral administration is rapid and extensive, with an absolute bioavailability of approximately 0.93 and a T max ranging from 0.25 to 4.0 hours. C max is slightly, but not significantly, higher in hyperthyroid patients, and both C max and AUC are significantly affected by the oral dose administered. •Volume of distribution (Drug A): No volume of distribution available •Volume of distribution (Drug B): The apparent volume of distribution of methimazole has been reported as roughly 20 L. Following oral administration, methimazole is highly concentrated in the thyroid gland - intrathyroidal methimazole levels are approximately 2 to 5 times higher than peak plasma levels, and remain high for 20 hours after ingestion. •Protein binding (Drug A): In vitro tests show that bupropion is 84% bound to human plasma proteins at concentrations up to 200 mcg per mL. The extent of protein binding of the hydroxybupropion metabolite is similar to that for bupropion, whereas the extent of protein binding of the threohydrobupropion metabolite is about half that seen with bupropion. •Protein binding (Drug B): Methimazole exhibits little-to-no protein binding, existing primarily as free drug in the serum. •Metabolism (Drug A): Bupropion is extensively metabolized in humans. Three metabolites are active: hydroxybupropion, which is formed via hydroxylation of the tert-butyl group of bupropion, and the amino-alcohol isomers, threohydrobupropion and erythrohydrobupropion, which are formed via reduction of the carbonyl group. In vitro findings suggest that CYP2B6 is the principal isoenzyme involved in the formation of hydroxybupropion, while cytochrome P450 enzymes are not involved in the formation of threohydrobupropion. Hydroxybupropion has been shown to have the same affinity as bupropion for the norepinephrine transporter (NET) but approximately 50% of its antidepressant activity despite reaching concentrations of ~10-fold higher than that of the parent drug. Oxidation of the bupropion side chain results in the formation of a glycine conjugate of meta-chlorobenzoic acid, which is then excreted as the major urinary metabolite. The potency and toxicity of the metabolites relative to bupropion have not been fully characterized. However, it has been demonstrated in an antidepressant screening test in mice that hydroxybupropion is one-half as potent as bupropion, while threohydrobupropion and erythrohydrobupropion are 5-fold less potent than bupropion. This may be of clinical importance because the plasma concentrations of the metabolites are as high as or higher than those of bupropion. Bupropion and its metabolites exhibit linear kinetics following chronic administration of 300 to 450 mg per day. •Metabolism (Drug B): Methimazole is rapidly and extensively metabolized by the liver, mainly via the CYP450 and FMO enzyme systems. Several metabolites have been identified, though the specific enzyme isoforms responsible for their formation are not entirely clear. One of the first methimazole metabolites identified, 3-methyl-2-thiohydantoin, may contribute to antithyroid activity - its antithyroid activity has been demonstrated in rats and may explain the prolonged duration of iodination inhibition following administration despite methimazole's relatively short half-life. A number of metabolites have been investigated as being the culprits behind methimazole-induced hepatotoxicity. Both glyoxal and N-methylthiourea have established cytotoxicity and are known metabolic products of methimazole's dihydrodiol intermediate. Sulfenic and sulfinic acid derivatives of methimazole are thought to be the ultimate toxicants responsible for hepatotoxicity, though their origin is unclear - they may arise from direct oxidation of methimazole via FMO, or from oxidation of N-methylthiourea further downstream in the metabolic process. •Route of elimination (Drug A): Bupropion is extensively metabolized in humans. Oxidation of the bupropion side chain results in the formation of a glycine conjugate of metachlorobenzoic acid, which is then excreted as the major urinary metabolite. Following oral administration of 200 mg of 14C-bupropion in humans, 87% and 10% of the radioactive dose were recovered in the urine and feces, respectively. However, the fraction of the oral dose of bupropion excreted unchanged was only 0.5%, a finding consistent with the extensive metabolism of bupropion. •Route of elimination (Drug B): Urinary excretion of unchanged methimazole has been reported to be between 7% and 12%. Elimination via feces appears to be limited, with a cumulative fecal excretion of 3% after administration of methimazole. Enterohepatic circulation also appears to play a role in the elimination of methimazole and its metabolites, as significant amounts of these substances are found in the bile post-administration. •Half-life (Drug A): 24 hours •Half-life (Drug B): Following a single intravenous bolus injection of 10mg of methimazole, the t 1/2 of the distribution phase was 0.17 hours and the t 1/2 of the elimination phase was 5.3 hours. Methimazole's primary active metabolite, 3-methyl-2-thiohydantoin, has a half-life approximately 3 times longer than its parent drug. Renal impairment does not appear to alter the half-life of methimazole, but patients with hepatic impairment showed an increase in half-life roughly proportional to the severity of their impairment - moderate insufficiency resulted in a elimination t 1/2 of 7.1 hours, while severe insufficiency resulted in an elimination t 1/2 of 22.1 hours. There does not appear to be any significant differences in half-life based on thyroid status (i.e. no difference between euthyroid and hyperthyroid patients). •Clearance (Drug A): No clearance available •Clearance (Drug B): Following a single intravenous bolus injection of 10mg of methimazole, clearance was found to be 5.70 L/h. Renal impairment does not appear to alter clearance of methimazole, but patients with hepatic impairment showed a reduction in clearance roughly proportional to the severity of their impairment - moderate insufficiency resulted in a clearance of 3.49 L/h, while severe insufficiency resulted in a clearance of 0.83 L/h. There does not appear to be any significant differences in clearance based on thyroid status (i.e. no difference between euthyroid and hyperthyroid patients). •Toxicity (Drug A): Symptoms of overdose include seizures, hallucinations, loss of consciousness, tachycardia, and cardiac arrest. •Toxicity (Drug B): The oral LD 50 of methimazole in rats is 2250 mg/kg. Signs and symptoms of methimazole overdose may include gastrointestinal distress, headache, fever, joint pain, pruritus, and edema. More serious adverse effects, such as aplastic anemia or agranulocytosis, may manifest within hours to days. Hepatitis, nephrotic syndrome, exfoliative dermatitis, and CNS effects such as neuropathy or CNS depression/stimulation are also potential, albeit less frequent, results of overdose. Management of overdose involves supportive treatment as dictated by the patient's status. This may involve monitoring of the patient's vital signs, blood gases, serum electrolytes, or bone marrow function as indicated. •Brand Names (Drug A): Aplenzin, Auvelity, Budeprion, Contrave, Forfivo, Wellbutrin, Zyban •Brand Names (Drug B): Tapazole •Synonyms (Drug A): No synonyms listed •Synonyms (Drug B): Methimazole Thiamazol Thiamazole Thiamazolum Tiamazol •Summary (Drug A): Bupropion is a norepinephrine and dopamine reuptake inhibitor used in the treatment of major depressive disorder (MDD), seasonal affective disorder (SAD), and as an aid to smoking cessation. •Summary (Drug B): Methimazole is a thionamide antithyroid agent that inhibits the actions of thyroid peroxidase, leading to a reduction in thyroid hormone synthesis and amelioration of hyperthyroidism.

Bupropion is extensively metabolized to hydroxybupropion by CYP2B6. The severity of the interaction is minor.

Question: Does Bupropion and Methimazole interact? Information: •Drug A: Bupropion •Drug B: Methimazole •Severity: MINOR •Description: The serum concentration of Bupropion can be increased when it is combined with Methimazole. •Extended Description: Bupropion is extensively metabolized to hydroxybupropion by CYP2B6. •Indication (Drug A): Bupropion is indicated for the treatment of major depressive disorder (MDD), seasonal affective disorder (SAD), and as an aid to smoking cessation. When used in combination with naltrexone as the marketed product ContraveⓇ, bupropion is indicated as an adjunct to a reduced-calorie diet and increased physical activity for chronic weight management in adults with an initial body mass index (BMI) of: 30 kg/m^2 or greater (obese) or 27 kg/m^2 or greater (overweight) in the presence of at least one weight-related comorbid condition (e.g., hypertension, type 2 diabetes mellitus, or dyslipidemia). Bupropion is also used off-label as a first-line treatment in patients with ADHD and comorbid bipolar disorder when used as an adjunct to mood stabilizers. •Indication (Drug B): In the United States, methimazole is indicated for the treatment of hyperthyroidism in patients with Graves' disease or toxic multinodular goiter for whom thyroidectomy or radioactive iodine therapy are not appropriate treatment options. Methimazole is also indicated for the amelioration of hyperthyroid symptoms in preparation for thyroidectomy or radioactive iodine therapy. In Canada, methimazole carries the above indications and is also indicated for the medical treatment of hyperthyroidism regardless of other available treatment options. •Pharmacodynamics (Drug A): Bupropion is chemically unrelated to tricyclic, tetracyclic, selective serotonin re-uptake inhibitors, or other known antidepressant agents. Compared to classical tricyclic antidepressants, Bupropion is a relatively weak inhibitor of the neuronal uptake of norepinephrine and dopamine. In addition, Bupropion does not inhibit monoamine oxidase. Bupropion has been found to be essentially inactive at the serotonin transporter (SERT)(IC50 >10 000 nM), however both bupropion and its primary metabolite hydroxybupropion have been found to block the function of cation-selective serotonin type 3A receptors (5-HT3ARs). Bupropion produces dose-related central nervous system (CNS) stimulant effects in animals, as evidenced by increased locomotor activity, increased rates of responding in various schedule-controlled operant behaviour tasks, and, at high doses, induction of mild stereotyped behaviour. Due to these stimulant effects and selective activity at dopamine and norepinephrine receptors, bupropion has been identified as having an abuse potential. Bupropion has a similar structure to the controlled substance Cathinone, and has been identified as having mild amphetamine-like activity, particularly when inhaled or injected. Bupropion is also known to lower the seizure threshold, making any pre-existing seizure conditions a contraindication to its use. This risk is exacerbated when bupropion is combined with other drugs or substances that lower the seizure threshold, such as cocaine, or in clinical situations that would increase the risk of a seizure such as abrupt alcohol or benzodiazepine withdrawal. As norepinephrine has been shown to have anticonvulsant properties, bupropion's inhibitory effects on NET are thought to contribute to its pro-convulsant activity. Bupropion has been shown to increase blood pressure and pose a risk for exacerbation of unmanaged or pre-existing hypertension, however, clinical trials of bupropion in smokers with CVD have not identified an increased incidence of CV events including stroke or heart attack. In clinical trials, the mean increase in systolic blood pressure associated with the use of bupropion was found to be 1.3 mmHg. •Pharmacodynamics (Drug B): Methimazole inhibits the synthesis of thyroid hormones resulting in an alleviation of hyperthyroidism. Onset of action occurs within 12 to 18 hours, and its duration of action is 36 to 72 hours, likely due to concentration of methimazole and some metabolites within the thyroid gland after administration. The most serious potential side effect of methimazole therapy is agranulocytosis, and patients should be instructed to monitor for, and report, any signs or symptoms of agranulocytosis such as fever or sore throat. Other cytopenias may also occur during methimazole therapy. There also exists the potential for severe hepatic toxicity with the use of methimazole, and monitoring for signs and symptoms of hepatic dysfunction, such as jaundice, anorexia, pruritus, and elevation in liver transaminases, is prudent in patients using this therapy. •Mechanism of action (Drug A): Bupropion is a norepinephrine/dopamine-reuptake inhibitor (NDRI) that exerts its pharmacological effects by weakly inhibiting the enzymes involved in the uptake of the neurotransmitters norepinephrine and dopamine from the synaptic cleft, therefore prolonging their duration of action within the neuronal synapse and the downstream effects of these neurotransmitters. More specifically, bupropion binds to the norepinephrine transporter (NET) and the dopamine transporter (DAT). Bupropion was originally classified as an "atypical" antidepressant because it does not exert the same effects as the classical antidepressants such as Monoamine Oxidase Inhibitors (MAOIs), Tricyclic Antidepressants (TCAs), or Selective Serotonin Reuptake Inhibitors (SSRIs). While it has comparable effectiveness to typical first-line options for the treatment of depression such as SSRIs, bupropion is a unique option for the treatment of MDD as it lacks any clinically relevant serotonergic effects, typical of other mood medications, or any effects on histamine or adrenaline receptors. Lack of activity at these receptors results in a more tolerable side effect profile; bupropion is less likely to cause sexual side effects, sedation, or weight gain as compared to SSRIs or TCAs, for example. When used as an aid to smoking cessation, bupropion is thought to confer its anti-craving and anti-withdrawal effects by inhibiting dopamine reuptake, which is thought to be involved in the reward pathways associated with nicotine, and through the antagonism of the nicotinic acetylcholinergic receptor (AChR), thereby blunting the effects of nicotine. Furthermore, the stimulatory effects produced by bupropion in the central nervous system are similar to nicotine's effects, making low doses of bupropion a suitable option as a nicotine substitute. When used in combination with naltrexone in the marketed product ContraveⓇ for chronic weight management, the two components are thought to have effects on areas of the brain involved in the regulation of food intake. This includes the hypothalamus, which is involved in appetite regulation, and the mesolimbic dopamine circuit, which is involved in reward pathways. Studies have shown that the combined activity of bupropion and naltrexone increase the firing rate of hypothalamic pro-opiomelanocortin (POMC) neurons and blockade of opioid receptor-mediated POMC auto-inhibition, which are associated with a reduction in food intake and increased energy expenditure. This combination was also found to reduce food intake when injected directly into the ventral tegmental area of the mesolimbic circuit in mice, which is an area associated with the regulation of reward pathways. •Mechanism of action (Drug B): Methimazole's primary mechanism of action appears to be interference in an early step in thyroid hormone synthesis involving thyroid peroxidase (TPO), however the exact method through which methimazole inhibits this step is unclear. TPO, along with hydrogen peroxide, normally catalyzes the conversion of iodide to iodine and then further catalyzes the incorporation of this iodine onto the 3 and/or 5 positions of the phenol rings of tyrosine residues in thyroglobulin. These thyroglobulin molecules then degrade within thyroid follicular cells to form either thyroxine (T 4 ) or tri-iodothyronine (T 3 ), which are the main hormones produced by the thyroid gland. Methimazole may directly inhibit TPO, but has been shown in vivo to instead act as a competitive substrate for TPO, thus becoming iodinated itself and interfering with the iodination of thyroglobulin. Another proposed theory is that methimazole’s sulfur moiety may interact directly with the iron atom at the centre of TPO’s heme molecule, thus inhibiting its ability to iodinate tyrosine residues. Other proposed mechanisms with weaker evidence include methimazole binding directly to thyroglobulin or direct inhibition of thyroglobulin itself. •Absorption (Drug A): Bupropion is currently available in 3 distinct, but bioequivalent formulations: immediate release (IR), sustained-release (SR), and extended-release (XL). Immediate Release Formulation In humans, following oral administration of bupropion hydrochloride tablets, peak plasma bupropion concentrations are usually achieved within 2 hours. IR formulations provide a short duration of action and are therefore generally dosed three times per day. Sustained Release Formulation In humans, following oral administration of bupropion hydrochloride sustained-release tablets (SR), peak plasma concentration (Cmax) of bupropion is usually achieved within 3 hours. SR formulations provide a 12-hour extended release of medication and are therefore generally dosed twice per day. Extended Release Formulation Following single oral administration of bupropion hydrochloride extended-release tablets (XL) to healthy volunteers, the median time to peak plasma concentrations for bupropion was approximately 5 hours. The presence of food did not affect the peak concentration or area under the curve of bupropion. XL formulations provide a 24-hour extended release of medication and are therefore generally dosed once per day/ In a trial comparing chronic dosing with bupropion hydrochloride extended-release tablets (SR) 150 mg twice daily to bupropion immediate-release formulation 100 mg 3 times daily, the steady state Cmax for bupropion after bupropion hydrochloride sustained-release tablets (SR) administration was approximately 85% of those achieved after bupropion immediate-release formulation administration. Exposure (AUC) to bupropion was equivalent for both formulations. Bioequivalence was also demonstrated for all three major active metabolites (i.e., hydroxybupropion, threohydrobupropion and erythrohydrobupropion) for both Cmax and AUC. Thus, at steady state, bupropion hydrochloride sustained-release tablets (SR) given twice daily, and the immediate-release formulation of bupropion given 3 times daily, are essentially bioequivalent for both bupropion and the 3 quantitatively important metabolites. Furthermore, in a study comparing 14-day dosing with bupropion hydrochloride extended-release tablets (XL), 300 mg once-daily to the immediate-release formulation of bupropion at 100 mg 3 times daily, equivalence was demonstrated for peak plasma concentration and area under the curve for bupropion and the three metabolites (hydroxybupropion, threohydrobupropion, and erythrohydrobupropion). Additionally, in a study comparing 14-day dosing with bupropion hydrochloride extended-release tablets (XL) 300 mg once daily to the sustained-release formulation of bupropion at 150 mg 2 times daily, equivalence was demonstrated for peak plasma concentration and area under the curve for bupropion and the three metabolites. Bupropion hydrochloride extended-release tablets (SR) can be taken with or without food. Bupropion Cmax and AUC were increased by 11% to 35% and 16% to 19%, respectively, when bupropion hydrochloride extended-release tablets (SR) was administered with food to healthy volunteers in three trials. The food effect is not considered clinically significant. Following a single-dose administration of bupropion hydrochloride extended-release tablets (SR) in humans, Cmax of bupropion's metabolite hydroxybupropion occurs approximately 6 hours post-dose and is approximately 10 times the peak level of the parent drug at steady state. The elimination half-life of hydroxybupropion is approximately 20 (±5) hours and its AUC at steady state is about 17 times that of bupropion. The times to peak concentrations for the erythrohydrobupropion and threohydrobupropion metabolites are similar to that of the hydroxybupropion metabolite. However, their elimination half-lives are longer, 33(±10) and 37 (±13) hours, respectively, and steady-state AUCs are 1.5 and 7 times that of bupropion, respectively. •Absorption (Drug B): Absorption of methimazole after oral administration is rapid and extensive, with an absolute bioavailability of approximately 0.93 and a T max ranging from 0.25 to 4.0 hours. C max is slightly, but not significantly, higher in hyperthyroid patients, and both C max and AUC are significantly affected by the oral dose administered. •Volume of distribution (Drug A): No volume of distribution available •Volume of distribution (Drug B): The apparent volume of distribution of methimazole has been reported as roughly 20 L. Following oral administration, methimazole is highly concentrated in the thyroid gland - intrathyroidal methimazole levels are approximately 2 to 5 times higher than peak plasma levels, and remain high for 20 hours after ingestion. •Protein binding (Drug A): In vitro tests show that bupropion is 84% bound to human plasma proteins at concentrations up to 200 mcg per mL. The extent of protein binding of the hydroxybupropion metabolite is similar to that for bupropion, whereas the extent of protein binding of the threohydrobupropion metabolite is about half that seen with bupropion. •Protein binding (Drug B): Methimazole exhibits little-to-no protein binding, existing primarily as free drug in the serum. •Metabolism (Drug A): Bupropion is extensively metabolized in humans. Three metabolites are active: hydroxybupropion, which is formed via hydroxylation of the tert-butyl group of bupropion, and the amino-alcohol isomers, threohydrobupropion and erythrohydrobupropion, which are formed via reduction of the carbonyl group. In vitro findings suggest that CYP2B6 is the principal isoenzyme involved in the formation of hydroxybupropion, while cytochrome P450 enzymes are not involved in the formation of threohydrobupropion. Hydroxybupropion has been shown to have the same affinity as bupropion for the norepinephrine transporter (NET) but approximately 50% of its antidepressant activity despite reaching concentrations of ~10-fold higher than that of the parent drug. Oxidation of the bupropion side chain results in the formation of a glycine conjugate of meta-chlorobenzoic acid, which is then excreted as the major urinary metabolite. The potency and toxicity of the metabolites relative to bupropion have not been fully characterized. However, it has been demonstrated in an antidepressant screening test in mice that hydroxybupropion is one-half as potent as bupropion, while threohydrobupropion and erythrohydrobupropion are 5-fold less potent than bupropion. This may be of clinical importance because the plasma concentrations of the metabolites are as high as or higher than those of bupropion. Bupropion and its metabolites exhibit linear kinetics following chronic administration of 300 to 450 mg per day. •Metabolism (Drug B): Methimazole is rapidly and extensively metabolized by the liver, mainly via the CYP450 and FMO enzyme systems. Several metabolites have been identified, though the specific enzyme isoforms responsible for their formation are not entirely clear. One of the first methimazole metabolites identified, 3-methyl-2-thiohydantoin, may contribute to antithyroid activity - its antithyroid activity has been demonstrated in rats and may explain the prolonged duration of iodination inhibition following administration despite methimazole's relatively short half-life. A number of metabolites have been investigated as being the culprits behind methimazole-induced hepatotoxicity. Both glyoxal and N-methylthiourea have established cytotoxicity and are known metabolic products of methimazole's dihydrodiol intermediate. Sulfenic and sulfinic acid derivatives of methimazole are thought to be the ultimate toxicants responsible for hepatotoxicity, though their origin is unclear - they may arise from direct oxidation of methimazole via FMO, or from oxidation of N-methylthiourea further downstream in the metabolic process. •Route of elimination (Drug A): Bupropion is extensively metabolized in humans. Oxidation of the bupropion side chain results in the formation of a glycine conjugate of metachlorobenzoic acid, which is then excreted as the major urinary metabolite. Following oral administration of 200 mg of 14C-bupropion in humans, 87% and 10% of the radioactive dose were recovered in the urine and feces, respectively. However, the fraction of the oral dose of bupropion excreted unchanged was only 0.5%, a finding consistent with the extensive metabolism of bupropion. •Route of elimination (Drug B): Urinary excretion of unchanged methimazole has been reported to be between 7% and 12%. Elimination via feces appears to be limited, with a cumulative fecal excretion of 3% after administration of methimazole. Enterohepatic circulation also appears to play a role in the elimination of methimazole and its metabolites, as significant amounts of these substances are found in the bile post-administration. •Half-life (Drug A): 24 hours •Half-life (Drug B): Following a single intravenous bolus injection of 10mg of methimazole, the t 1/2 of the distribution phase was 0.17 hours and the t 1/2 of the elimination phase was 5.3 hours. Methimazole's primary active metabolite, 3-methyl-2-thiohydantoin, has a half-life approximately 3 times longer than its parent drug. Renal impairment does not appear to alter the half-life of methimazole, but patients with hepatic impairment showed an increase in half-life roughly proportional to the severity of their impairment - moderate insufficiency resulted in a elimination t 1/2 of 7.1 hours, while severe insufficiency resulted in an elimination t 1/2 of 22.1 hours. There does not appear to be any significant differences in half-life based on thyroid status (i.e. no difference between euthyroid and hyperthyroid patients). •Clearance (Drug A): No clearance available •Clearance (Drug B): Following a single intravenous bolus injection of 10mg of methimazole, clearance was found to be 5.70 L/h. Renal impairment does not appear to alter clearance of methimazole, but patients with hepatic impairment showed a reduction in clearance roughly proportional to the severity of their impairment - moderate insufficiency resulted in a clearance of 3.49 L/h, while severe insufficiency resulted in a clearance of 0.83 L/h. There does not appear to be any significant differences in clearance based on thyroid status (i.e. no difference between euthyroid and hyperthyroid patients). •Toxicity (Drug A): Symptoms of overdose include seizures, hallucinations, loss of consciousness, tachycardia, and cardiac arrest. •Toxicity (Drug B): The oral LD 50 of methimazole in rats is 2250 mg/kg. Signs and symptoms of methimazole overdose may include gastrointestinal distress, headache, fever, joint pain, pruritus, and edema. More serious adverse effects, such as aplastic anemia or agranulocytosis, may manifest within hours to days. Hepatitis, nephrotic syndrome, exfoliative dermatitis, and CNS effects such as neuropathy or CNS depression/stimulation are also potential, albeit less frequent, results of overdose. Management of overdose involves supportive treatment as dictated by the patient's status. This may involve monitoring of the patient's vital signs, blood gases, serum electrolytes, or bone marrow function as indicated. •Brand Names (Drug A): Aplenzin, Auvelity, Budeprion, Contrave, Forfivo, Wellbutrin, Zyban •Brand Names (Drug B): Tapazole •Synonyms (Drug A): No synonyms listed •Synonyms (Drug B): Methimazole Thiamazol Thiamazole Thiamazolum Tiamazol •Summary (Drug A): Bupropion is a norepinephrine and dopamine reuptake inhibitor used in the treatment of major depressive disorder (MDD), seasonal affective disorder (SAD), and as an aid to smoking cessation. •Summary (Drug B): Methimazole is a thionamide antithyroid agent that inhibits the actions of thyroid peroxidase, leading to a reduction in thyroid hormone synthesis and amelioration of hyperthyroidism. Output: Bupropion is extensively metabolized to hydroxybupropion by CYP2B6. The severity of the interaction is minor.

Does Bupropion and Methocarbamol interact?

•Drug A: Bupropion •Drug B: Methocarbamol •Severity: MODERATE •Description: The risk or severity of CNS depression can be increased when Methocarbamol is combined with Bupropion. •Extended Description: Central nervous system (CNS) depressants can cause sedation, falls, respiratory depression, coma, and death.2,3 The potential interaction between a CNS depressant and another CNS depressant drug due to synergistic effects is well documented in the literature, although the risk and severity of CNS depression vary from each drug. The subject and affected drugs are both CNS depressants that, when co-administered, may result in a more profound CNS depression. As the risk and severity of CNS depression resulting from the combined use of CNS depressants vary from each agent, each interaction between CNS depressants should be considered individually. •Indication (Drug A): Bupropion is indicated for the treatment of major depressive disorder (MDD), seasonal affective disorder (SAD), and as an aid to smoking cessation. When used in combination with naltrexone as the marketed product ContraveⓇ, bupropion is indicated as an adjunct to a reduced-calorie diet and increased physical activity for chronic weight management in adults with an initial body mass index (BMI) of: 30 kg/m^2 or greater (obese) or 27 kg/m^2 or greater (overweight) in the presence of at least one weight-related comorbid condition (e.g., hypertension, type 2 diabetes mellitus, or dyslipidemia). Bupropion is also used off-label as a first-line treatment in patients with ADHD and comorbid bipolar disorder when used as an adjunct to mood stabilizers. •Indication (Drug B): Methocarbamol tablets and intramuscular injections are indicated in the United States as an adjunct to rest, physical therapy, and other measures for the relief of discomforts associated with acute, painful musculoskeletal conditions. Oral methocarbamol in America may be given up to 1500mg 4 times daily for 2-3 days. In Canada, methocarbamol containing oral formulations are sold over the counter for pain associated with muscle spasm. However, if these combination formulations include codeine, they are prescription only. •Pharmacodynamics (Drug A): Bupropion is chemically unrelated to tricyclic, tetracyclic, selective serotonin re-uptake inhibitors, or other known antidepressant agents. Compared to classical tricyclic antidepressants, Bupropion is a relatively weak inhibitor of the neuronal uptake of norepinephrine and dopamine. In addition, Bupropion does not inhibit monoamine oxidase. Bupropion has been found to be essentially inactive at the serotonin transporter (SERT)(IC50 >10 000 nM), however both bupropion and its primary metabolite hydroxybupropion have been found to block the function of cation-selective serotonin type 3A receptors (5-HT3ARs). Bupropion produces dose-related central nervous system (CNS) stimulant effects in animals, as evidenced by increased locomotor activity, increased rates of responding in various schedule-controlled operant behaviour tasks, and, at high doses, induction of mild stereotyped behaviour. Due to these stimulant effects and selective activity at dopamine and norepinephrine receptors, bupropion has been identified as having an abuse potential. Bupropion has a similar structure to the controlled substance Cathinone, and has been identified as having mild amphetamine-like activity, particularly when inhaled or injected. Bupropion is also known to lower the seizure threshold, making any pre-existing seizure conditions a contraindication to its use. This risk is exacerbated when bupropion is combined with other drugs or substances that lower the seizure threshold, such as cocaine, or in clinical situations that would increase the risk of a seizure such as abrupt alcohol or benzodiazepine withdrawal. As norepinephrine has been shown to have anticonvulsant properties, bupropion's inhibitory effects on NET are thought to contribute to its pro-convulsant activity. Bupropion has been shown to increase blood pressure and pose a risk for exacerbation of unmanaged or pre-existing hypertension, however, clinical trials of bupropion in smokers with CVD have not identified an increased incidence of CV events including stroke or heart attack. In clinical trials, the mean increase in systolic blood pressure associated with the use of bupropion was found to be 1.3 mmHg. •Pharmacodynamics (Drug B): Methacarbamol is a skeletal muscle relaxant with an unknown mechanism of action. Methacarbamol has been shown to block spinal polysynaptic reflexes, decrease nerve transmission in spinal and supraspinal polysynaptic pathways, and prolong the refractory period of muscle cells. Methocarbamol does not act as a local anesthetic upon injection. In animal studies, methocarbamol also prevents convulsions after electric shock. •Mechanism of action (Drug A): Bupropion is a norepinephrine/dopamine-reuptake inhibitor (NDRI) that exerts its pharmacological effects by weakly inhibiting the enzymes involved in the uptake of the neurotransmitters norepinephrine and dopamine from the synaptic cleft, therefore prolonging their duration of action within the neuronal synapse and the downstream effects of these neurotransmitters. More specifically, bupropion binds to the norepinephrine transporter (NET) and the dopamine transporter (DAT). Bupropion was originally classified as an "atypical" antidepressant because it does not exert the same effects as the classical antidepressants such as Monoamine Oxidase Inhibitors (MAOIs), Tricyclic Antidepressants (TCAs), or Selective Serotonin Reuptake Inhibitors (SSRIs). While it has comparable effectiveness to typical first-line options for the treatment of depression such as SSRIs, bupropion is a unique option for the treatment of MDD as it lacks any clinically relevant serotonergic effects, typical of other mood medications, or any effects on histamine or adrenaline receptors. Lack of activity at these receptors results in a more tolerable side effect profile; bupropion is less likely to cause sexual side effects, sedation, or weight gain as compared to SSRIs or TCAs, for example. When used as an aid to smoking cessation, bupropion is thought to confer its anti-craving and anti-withdrawal effects by inhibiting dopamine reuptake, which is thought to be involved in the reward pathways associated with nicotine, and through the antagonism of the nicotinic acetylcholinergic receptor (AChR), thereby blunting the effects of nicotine. Furthermore, the stimulatory effects produced by bupropion in the central nervous system are similar to nicotine's effects, making low doses of bupropion a suitable option as a nicotine substitute. When used in combination with naltrexone in the marketed product ContraveⓇ for chronic weight management, the two components are thought to have effects on areas of the brain involved in the regulation of food intake. This includes the hypothalamus, which is involved in appetite regulation, and the mesolimbic dopamine circuit, which is involved in reward pathways. Studies have shown that the combined activity of bupropion and naltrexone increase the firing rate of hypothalamic pro-opiomelanocortin (POMC) neurons and blockade of opioid receptor-mediated POMC auto-inhibition, which are associated with a reduction in food intake and increased energy expenditure. This combination was also found to reduce food intake when injected directly into the ventral tegmental area of the mesolimbic circuit in mice, which is an area associated with the regulation of reward pathways. •Mechanism of action (Drug B): The mechanism of action of methocarbamol is thought to be dependant on its central nervous system depressant activity. This action may be mediated through blocking spinal polysynaptic reflexes, decreasing nerve transmission in spinal and supraspinal polysynaptic pathways, and prolonging the refractory period of muscle cells. Methocarbamol has been found to have no effect on contraction of muscle fibres, motor end plates, or nerve fibres. •Absorption (Drug A): Bupropion is currently available in 3 distinct, but bioequivalent formulations: immediate release (IR), sustained-release (SR), and extended-release (XL). Immediate Release Formulation In humans, following oral administration of bupropion hydrochloride tablets, peak plasma bupropion concentrations are usually achieved within 2 hours. IR formulations provide a short duration of action and are therefore generally dosed three times per day. Sustained Release Formulation In humans, following oral administration of bupropion hydrochloride sustained-release tablets (SR), peak plasma concentration (Cmax) of bupropion is usually achieved within 3 hours. SR formulations provide a 12-hour extended release of medication and are therefore generally dosed twice per day. Extended Release Formulation Following single oral administration of bupropion hydrochloride extended-release tablets (XL) to healthy volunteers, the median time to peak plasma concentrations for bupropion was approximately 5 hours. The presence of food did not affect the peak concentration or area under the curve of bupropion. XL formulations provide a 24-hour extended release of medication and are therefore generally dosed once per day/ In a trial comparing chronic dosing with bupropion hydrochloride extended-release tablets (SR) 150 mg twice daily to bupropion immediate-release formulation 100 mg 3 times daily, the steady state Cmax for bupropion after bupropion hydrochloride sustained-release tablets (SR) administration was approximately 85% of those achieved after bupropion immediate-release formulation administration. Exposure (AUC) to bupropion was equivalent for both formulations. Bioequivalence was also demonstrated for all three major active metabolites (i.e., hydroxybupropion, threohydrobupropion and erythrohydrobupropion) for both Cmax and AUC. Thus, at steady state, bupropion hydrochloride sustained-release tablets (SR) given twice daily, and the immediate-release formulation of bupropion given 3 times daily, are essentially bioequivalent for both bupropion and the 3 quantitatively important metabolites. Furthermore, in a study comparing 14-day dosing with bupropion hydrochloride extended-release tablets (XL), 300 mg once-daily to the immediate-release formulation of bupropion at 100 mg 3 times daily, equivalence was demonstrated for peak plasma concentration and area under the curve for bupropion and the three metabolites (hydroxybupropion, threohydrobupropion, and erythrohydrobupropion). Additionally, in a study comparing 14-day dosing with bupropion hydrochloride extended-release tablets (XL) 300 mg once daily to the sustained-release formulation of bupropion at 150 mg 2 times daily, equivalence was demonstrated for peak plasma concentration and area under the curve for bupropion and the three metabolites. Bupropion hydrochloride extended-release tablets (SR) can be taken with or without food. Bupropion Cmax and AUC were increased by 11% to 35% and 16% to 19%, respectively, when bupropion hydrochloride extended-release tablets (SR) was administered with food to healthy volunteers in three trials. The food effect is not considered clinically significant. Following a single-dose administration of bupropion hydrochloride extended-release tablets (SR) in humans, Cmax of bupropion's metabolite hydroxybupropion occurs approximately 6 hours post-dose and is approximately 10 times the peak level of the parent drug at steady state. The elimination half-life of hydroxybupropion is approximately 20 (±5) hours and its AUC at steady state is about 17 times that of bupropion. The times to peak concentrations for the erythrohydrobupropion and threohydrobupropion metabolites are similar to that of the hydroxybupropion metabolite. However, their elimination half-lives are longer, 33(±10) and 37 (±13) hours, respectively, and steady-state AUCs are 1.5 and 7 times that of bupropion, respectively. •Absorption (Drug B): The time to maximum concentration is 1.1 hours for both healthy patients and those on hemodialysis. The maximum plasma concentration is 21.3mg/L for healthy patients and 28.7mg/L in hemodialysis patients. The area under the curve for healthy patients is 52.5mg/L*hr and 87.1mg/L*hr in hemodialysis patients. AUC% based on terminal elimination half life is 2% for healthy patients and 4% for hemodialysis patients. Older studies report maximum plasma concentrations in 0.5 hours. •Volume of distribution (Drug A): No volume of distribution available •Volume of distribution (Drug B): Volume of distribution data in humans is scarce. In horses, the volume of distribution is 515-942mL/kg at steady state or 724-1130mL/kg. •Protein binding (Drug A): In vitro tests show that bupropion is 84% bound to human plasma proteins at concentrations up to 200 mcg per mL. The extent of protein binding of the hydroxybupropion metabolite is similar to that for bupropion, whereas the extent of protein binding of the threohydrobupropion metabolite is about half that seen with bupropion. •Protein binding (Drug B): Methocarbamol is 46-50% protein bound in healthy patients and 47.3-48.9% protein bound in hemodialysis patients. •Metabolism (Drug A): Bupropion is extensively metabolized in humans. Three metabolites are active: hydroxybupropion, which is formed via hydroxylation of the tert-butyl group of bupropion, and the amino-alcohol isomers, threohydrobupropion and erythrohydrobupropion, which are formed via reduction of the carbonyl group. In vitro findings suggest that CYP2B6 is the principal isoenzyme involved in the formation of hydroxybupropion, while cytochrome P450 enzymes are not involved in the formation of threohydrobupropion. Hydroxybupropion has been shown to have the same affinity as bupropion for the norepinephrine transporter (NET) but approximately 50% of its antidepressant activity despite reaching concentrations of ~10-fold higher than that of the parent drug. Oxidation of the bupropion side chain results in the formation of a glycine conjugate of meta-chlorobenzoic acid, which is then excreted as the major urinary metabolite. The potency and toxicity of the metabolites relative to bupropion have not been fully characterized. However, it has been demonstrated in an antidepressant screening test in mice that hydroxybupropion is one-half as potent as bupropion, while threohydrobupropion and erythrohydrobupropion are 5-fold less potent than bupropion. This may be of clinical importance because the plasma concentrations of the metabolites are as high as or higher than those of bupropion. Bupropion and its metabolites exhibit linear kinetics following chronic administration of 300 to 450 mg per day. •Metabolism (Drug B): Methocarbamol is metabolized in the liver by demethylation to 3-(2-hydroxyphenoxy)-1,2-propanediol-1-carbamate or hydroxylation to 3-(4-hydroxy-2-methoxyphenoxy)-1,2-propanediol-1-carbamate. Methocarbamol and its metabolites are conjugated through glucuronidation or sulfation. •Route of elimination (Drug A): Bupropion is extensively metabolized in humans. Oxidation of the bupropion side chain results in the formation of a glycine conjugate of metachlorobenzoic acid, which is then excreted as the major urinary metabolite. Following oral administration of 200 mg of 14C-bupropion in humans, 87% and 10% of the radioactive dose were recovered in the urine and feces, respectively. However, the fraction of the oral dose of bupropion excreted unchanged was only 0.5%, a finding consistent with the extensive metabolism of bupropion. •Route of elimination (Drug B): In humans the majority of the dose is eliminated in the urine. In dogs, 88.85% of the dose is eliminated in urine and 2.14% in the feces. In rats, 84.5-92.5% of the dose is eliminated in the urine and 0-13.3% is eliminated in the feces. •Half-life (Drug A): 24 hours •Half-life (Drug B): The elimination half life is 1.14 hours in healthy subjects and 1.24 hours in subjects with renal insufficiency. Older studies report half lives of 1.6-2.15 hours. •Clearance (Drug A): No clearance available •Clearance (Drug B): 0.2-0.8L/h/kg. •Toxicity (Drug A): Symptoms of overdose include seizures, hallucinations, loss of consciousness, tachycardia, and cardiac arrest. •Toxicity (Drug B): Overdose of methocarbamol may be associated with alcohol and other central nervous system depressants. Patients may experience nausea, drowsiness, blurred vision, hypotension, seizures, and coma. Treatment of overdose is generally through airway maintenance, monitoring urinary output, vital signs, and giving fluid intravenously if necessary. The oral LD50 in rats is 3576.2mg/kg. The FDA has classified methocarbamol as pregnancy category C. Animal and human studies have not been performed to determine the risks to a fetus, however fetal and congenital abnormalities have been reported. Methocarbamol is excreted in the milk of dogs, however it is unknown if this is also the case for humans. Caution should be exercised when taking methocarbamol while breastfeeding. Studies to assess the carcinogenicity, mutagenicity, or effects on fertility of methocarbamol have not been performed. •Brand Names (Drug A): Aplenzin, Auvelity, Budeprion, Contrave, Forfivo, Wellbutrin, Zyban •Brand Names (Drug B): Robaxacet, Robaxacet-8, Robaxin, Robaxisal •Synonyms (Drug A): No synonyms listed •Synonyms (Drug B): Methocarbamol Méthocarbamol Methocarbamolum Metocarbamol Metocarbamolo •Summary (Drug A): Bupropion is a norepinephrine and dopamine reuptake inhibitor used in the treatment of major depressive disorder (MDD), seasonal affective disorder (SAD), and as an aid to smoking cessation. •Summary (Drug B): Methocarbamol is a CNS depressant indicated with rest, physical therapy and other treatments to control the discomfort associated with various acute musculoskeletal conditions.

Central nervous system (CNS) depressants can cause sedation, falls, respiratory depression, coma, and death.2,3 The potential interaction between a CNS depressant and another CNS depressant drug due to synergistic effects is well documented in the literature, although the risk and severity of CNS depression vary from each drug. The subject and affected drugs are both CNS depressants that, when co-administered, may result in a more profound CNS depression. As the risk and severity of CNS depression resulting from the combined use of CNS depressants vary from each agent, each interaction between CNS depressants should be considered individually. The severity of the interaction is moderate.

Question: Does Bupropion and Methocarbamol interact? Information: •Drug A: Bupropion •Drug B: Methocarbamol •Severity: MODERATE •Description: The risk or severity of CNS depression can be increased when Methocarbamol is combined with Bupropion. •Extended Description: Central nervous system (CNS) depressants can cause sedation, falls, respiratory depression, coma, and death.2,3 The potential interaction between a CNS depressant and another CNS depressant drug due to synergistic effects is well documented in the literature, although the risk and severity of CNS depression vary from each drug. The subject and affected drugs are both CNS depressants that, when co-administered, may result in a more profound CNS depression. As the risk and severity of CNS depression resulting from the combined use of CNS depressants vary from each agent, each interaction between CNS depressants should be considered individually. •Indication (Drug A): Bupropion is indicated for the treatment of major depressive disorder (MDD), seasonal affective disorder (SAD), and as an aid to smoking cessation. When used in combination with naltrexone as the marketed product ContraveⓇ, bupropion is indicated as an adjunct to a reduced-calorie diet and increased physical activity for chronic weight management in adults with an initial body mass index (BMI) of: 30 kg/m^2 or greater (obese) or 27 kg/m^2 or greater (overweight) in the presence of at least one weight-related comorbid condition (e.g., hypertension, type 2 diabetes mellitus, or dyslipidemia). Bupropion is also used off-label as a first-line treatment in patients with ADHD and comorbid bipolar disorder when used as an adjunct to mood stabilizers. •Indication (Drug B): Methocarbamol tablets and intramuscular injections are indicated in the United States as an adjunct to rest, physical therapy, and other measures for the relief of discomforts associated with acute, painful musculoskeletal conditions. Oral methocarbamol in America may be given up to 1500mg 4 times daily for 2-3 days. In Canada, methocarbamol containing oral formulations are sold over the counter for pain associated with muscle spasm. However, if these combination formulations include codeine, they are prescription only. •Pharmacodynamics (Drug A): Bupropion is chemically unrelated to tricyclic, tetracyclic, selective serotonin re-uptake inhibitors, or other known antidepressant agents. Compared to classical tricyclic antidepressants, Bupropion is a relatively weak inhibitor of the neuronal uptake of norepinephrine and dopamine. In addition, Bupropion does not inhibit monoamine oxidase. Bupropion has been found to be essentially inactive at the serotonin transporter (SERT)(IC50 >10 000 nM), however both bupropion and its primary metabolite hydroxybupropion have been found to block the function of cation-selective serotonin type 3A receptors (5-HT3ARs). Bupropion produces dose-related central nervous system (CNS) stimulant effects in animals, as evidenced by increased locomotor activity, increased rates of responding in various schedule-controlled operant behaviour tasks, and, at high doses, induction of mild stereotyped behaviour. Due to these stimulant effects and selective activity at dopamine and norepinephrine receptors, bupropion has been identified as having an abuse potential. Bupropion has a similar structure to the controlled substance Cathinone, and has been identified as having mild amphetamine-like activity, particularly when inhaled or injected. Bupropion is also known to lower the seizure threshold, making any pre-existing seizure conditions a contraindication to its use. This risk is exacerbated when bupropion is combined with other drugs or substances that lower the seizure threshold, such as cocaine, or in clinical situations that would increase the risk of a seizure such as abrupt alcohol or benzodiazepine withdrawal. As norepinephrine has been shown to have anticonvulsant properties, bupropion's inhibitory effects on NET are thought to contribute to its pro-convulsant activity. Bupropion has been shown to increase blood pressure and pose a risk for exacerbation of unmanaged or pre-existing hypertension, however, clinical trials of bupropion in smokers with CVD have not identified an increased incidence of CV events including stroke or heart attack. In clinical trials, the mean increase in systolic blood pressure associated with the use of bupropion was found to be 1.3 mmHg. •Pharmacodynamics (Drug B): Methacarbamol is a skeletal muscle relaxant with an unknown mechanism of action. Methacarbamol has been shown to block spinal polysynaptic reflexes, decrease nerve transmission in spinal and supraspinal polysynaptic pathways, and prolong the refractory period of muscle cells. Methocarbamol does not act as a local anesthetic upon injection. In animal studies, methocarbamol also prevents convulsions after electric shock. •Mechanism of action (Drug A): Bupropion is a norepinephrine/dopamine-reuptake inhibitor (NDRI) that exerts its pharmacological effects by weakly inhibiting the enzymes involved in the uptake of the neurotransmitters norepinephrine and dopamine from the synaptic cleft, therefore prolonging their duration of action within the neuronal synapse and the downstream effects of these neurotransmitters. More specifically, bupropion binds to the norepinephrine transporter (NET) and the dopamine transporter (DAT). Bupropion was originally classified as an "atypical" antidepressant because it does not exert the same effects as the classical antidepressants such as Monoamine Oxidase Inhibitors (MAOIs), Tricyclic Antidepressants (TCAs), or Selective Serotonin Reuptake Inhibitors (SSRIs). While it has comparable effectiveness to typical first-line options for the treatment of depression such as SSRIs, bupropion is a unique option for the treatment of MDD as it lacks any clinically relevant serotonergic effects, typical of other mood medications, or any effects on histamine or adrenaline receptors. Lack of activity at these receptors results in a more tolerable side effect profile; bupropion is less likely to cause sexual side effects, sedation, or weight gain as compared to SSRIs or TCAs, for example. When used as an aid to smoking cessation, bupropion is thought to confer its anti-craving and anti-withdrawal effects by inhibiting dopamine reuptake, which is thought to be involved in the reward pathways associated with nicotine, and through the antagonism of the nicotinic acetylcholinergic receptor (AChR), thereby blunting the effects of nicotine. Furthermore, the stimulatory effects produced by bupropion in the central nervous system are similar to nicotine's effects, making low doses of bupropion a suitable option as a nicotine substitute. When used in combination with naltrexone in the marketed product ContraveⓇ for chronic weight management, the two components are thought to have effects on areas of the brain involved in the regulation of food intake. This includes the hypothalamus, which is involved in appetite regulation, and the mesolimbic dopamine circuit, which is involved in reward pathways. Studies have shown that the combined activity of bupropion and naltrexone increase the firing rate of hypothalamic pro-opiomelanocortin (POMC) neurons and blockade of opioid receptor-mediated POMC auto-inhibition, which are associated with a reduction in food intake and increased energy expenditure. This combination was also found to reduce food intake when injected directly into the ventral tegmental area of the mesolimbic circuit in mice, which is an area associated with the regulation of reward pathways. •Mechanism of action (Drug B): The mechanism of action of methocarbamol is thought to be dependant on its central nervous system depressant activity. This action may be mediated through blocking spinal polysynaptic reflexes, decreasing nerve transmission in spinal and supraspinal polysynaptic pathways, and prolonging the refractory period of muscle cells. Methocarbamol has been found to have no effect on contraction of muscle fibres, motor end plates, or nerve fibres. •Absorption (Drug A): Bupropion is currently available in 3 distinct, but bioequivalent formulations: immediate release (IR), sustained-release (SR), and extended-release (XL). Immediate Release Formulation In humans, following oral administration of bupropion hydrochloride tablets, peak plasma bupropion concentrations are usually achieved within 2 hours. IR formulations provide a short duration of action and are therefore generally dosed three times per day. Sustained Release Formulation In humans, following oral administration of bupropion hydrochloride sustained-release tablets (SR), peak plasma concentration (Cmax) of bupropion is usually achieved within 3 hours. SR formulations provide a 12-hour extended release of medication and are therefore generally dosed twice per day. Extended Release Formulation Following single oral administration of bupropion hydrochloride extended-release tablets (XL) to healthy volunteers, the median time to peak plasma concentrations for bupropion was approximately 5 hours. The presence of food did not affect the peak concentration or area under the curve of bupropion. XL formulations provide a 24-hour extended release of medication and are therefore generally dosed once per day/ In a trial comparing chronic dosing with bupropion hydrochloride extended-release tablets (SR) 150 mg twice daily to bupropion immediate-release formulation 100 mg 3 times daily, the steady state Cmax for bupropion after bupropion hydrochloride sustained-release tablets (SR) administration was approximately 85% of those achieved after bupropion immediate-release formulation administration. Exposure (AUC) to bupropion was equivalent for both formulations. Bioequivalence was also demonstrated for all three major active metabolites (i.e., hydroxybupropion, threohydrobupropion and erythrohydrobupropion) for both Cmax and AUC. Thus, at steady state, bupropion hydrochloride sustained-release tablets (SR) given twice daily, and the immediate-release formulation of bupropion given 3 times daily, are essentially bioequivalent for both bupropion and the 3 quantitatively important metabolites. Furthermore, in a study comparing 14-day dosing with bupropion hydrochloride extended-release tablets (XL), 300 mg once-daily to the immediate-release formulation of bupropion at 100 mg 3 times daily, equivalence was demonstrated for peak plasma concentration and area under the curve for bupropion and the three metabolites (hydroxybupropion, threohydrobupropion, and erythrohydrobupropion). Additionally, in a study comparing 14-day dosing with bupropion hydrochloride extended-release tablets (XL) 300 mg once daily to the sustained-release formulation of bupropion at 150 mg 2 times daily, equivalence was demonstrated for peak plasma concentration and area under the curve for bupropion and the three metabolites. Bupropion hydrochloride extended-release tablets (SR) can be taken with or without food. Bupropion Cmax and AUC were increased by 11% to 35% and 16% to 19%, respectively, when bupropion hydrochloride extended-release tablets (SR) was administered with food to healthy volunteers in three trials. The food effect is not considered clinically significant. Following a single-dose administration of bupropion hydrochloride extended-release tablets (SR) in humans, Cmax of bupropion's metabolite hydroxybupropion occurs approximately 6 hours post-dose and is approximately 10 times the peak level of the parent drug at steady state. The elimination half-life of hydroxybupropion is approximately 20 (±5) hours and its AUC at steady state is about 17 times that of bupropion. The times to peak concentrations for the erythrohydrobupropion and threohydrobupropion metabolites are similar to that of the hydroxybupropion metabolite. However, their elimination half-lives are longer, 33(±10) and 37 (±13) hours, respectively, and steady-state AUCs are 1.5 and 7 times that of bupropion, respectively. •Absorption (Drug B): The time to maximum concentration is 1.1 hours for both healthy patients and those on hemodialysis. The maximum plasma concentration is 21.3mg/L for healthy patients and 28.7mg/L in hemodialysis patients. The area under the curve for healthy patients is 52.5mg/L*hr and 87.1mg/L*hr in hemodialysis patients. AUC% based on terminal elimination half life is 2% for healthy patients and 4% for hemodialysis patients. Older studies report maximum plasma concentrations in 0.5 hours. •Volume of distribution (Drug A): No volume of distribution available •Volume of distribution (Drug B): Volume of distribution data in humans is scarce. In horses, the volume of distribution is 515-942mL/kg at steady state or 724-1130mL/kg. •Protein binding (Drug A): In vitro tests show that bupropion is 84% bound to human plasma proteins at concentrations up to 200 mcg per mL. The extent of protein binding of the hydroxybupropion metabolite is similar to that for bupropion, whereas the extent of protein binding of the threohydrobupropion metabolite is about half that seen with bupropion. •Protein binding (Drug B): Methocarbamol is 46-50% protein bound in healthy patients and 47.3-48.9% protein bound in hemodialysis patients. •Metabolism (Drug A): Bupropion is extensively metabolized in humans. Three metabolites are active: hydroxybupropion, which is formed via hydroxylation of the tert-butyl group of bupropion, and the amino-alcohol isomers, threohydrobupropion and erythrohydrobupropion, which are formed via reduction of the carbonyl group. In vitro findings suggest that CYP2B6 is the principal isoenzyme involved in the formation of hydroxybupropion, while cytochrome P450 enzymes are not involved in the formation of threohydrobupropion. Hydroxybupropion has been shown to have the same affinity as bupropion for the norepinephrine transporter (NET) but approximately 50% of its antidepressant activity despite reaching concentrations of ~10-fold higher than that of the parent drug. Oxidation of the bupropion side chain results in the formation of a glycine conjugate of meta-chlorobenzoic acid, which is then excreted as the major urinary metabolite. The potency and toxicity of the metabolites relative to bupropion have not been fully characterized. However, it has been demonstrated in an antidepressant screening test in mice that hydroxybupropion is one-half as potent as bupropion, while threohydrobupropion and erythrohydrobupropion are 5-fold less potent than bupropion. This may be of clinical importance because the plasma concentrations of the metabolites are as high as or higher than those of bupropion. Bupropion and its metabolites exhibit linear kinetics following chronic administration of 300 to 450 mg per day. •Metabolism (Drug B): Methocarbamol is metabolized in the liver by demethylation to 3-(2-hydroxyphenoxy)-1,2-propanediol-1-carbamate or hydroxylation to 3-(4-hydroxy-2-methoxyphenoxy)-1,2-propanediol-1-carbamate. Methocarbamol and its metabolites are conjugated through glucuronidation or sulfation. •Route of elimination (Drug A): Bupropion is extensively metabolized in humans. Oxidation of the bupropion side chain results in the formation of a glycine conjugate of metachlorobenzoic acid, which is then excreted as the major urinary metabolite. Following oral administration of 200 mg of 14C-bupropion in humans, 87% and 10% of the radioactive dose were recovered in the urine and feces, respectively. However, the fraction of the oral dose of bupropion excreted unchanged was only 0.5%, a finding consistent with the extensive metabolism of bupropion. •Route of elimination (Drug B): In humans the majority of the dose is eliminated in the urine. In dogs, 88.85% of the dose is eliminated in urine and 2.14% in the feces. In rats, 84.5-92.5% of the dose is eliminated in the urine and 0-13.3% is eliminated in the feces. •Half-life (Drug A): 24 hours •Half-life (Drug B): The elimination half life is 1.14 hours in healthy subjects and 1.24 hours in subjects with renal insufficiency. Older studies report half lives of 1.6-2.15 hours. •Clearance (Drug A): No clearance available •Clearance (Drug B): 0.2-0.8L/h/kg. •Toxicity (Drug A): Symptoms of overdose include seizures, hallucinations, loss of consciousness, tachycardia, and cardiac arrest. •Toxicity (Drug B): Overdose of methocarbamol may be associated with alcohol and other central nervous system depressants. Patients may experience nausea, drowsiness, blurred vision, hypotension, seizures, and coma. Treatment of overdose is generally through airway maintenance, monitoring urinary output, vital signs, and giving fluid intravenously if necessary. The oral LD50 in rats is 3576.2mg/kg. The FDA has classified methocarbamol as pregnancy category C. Animal and human studies have not been performed to determine the risks to a fetus, however fetal and congenital abnormalities have been reported. Methocarbamol is excreted in the milk of dogs, however it is unknown if this is also the case for humans. Caution should be exercised when taking methocarbamol while breastfeeding. Studies to assess the carcinogenicity, mutagenicity, or effects on fertility of methocarbamol have not been performed. •Brand Names (Drug A): Aplenzin, Auvelity, Budeprion, Contrave, Forfivo, Wellbutrin, Zyban •Brand Names (Drug B): Robaxacet, Robaxacet-8, Robaxin, Robaxisal •Synonyms (Drug A): No synonyms listed •Synonyms (Drug B): Methocarbamol Méthocarbamol Methocarbamolum Metocarbamol Metocarbamolo •Summary (Drug A): Bupropion is a norepinephrine and dopamine reuptake inhibitor used in the treatment of major depressive disorder (MDD), seasonal affective disorder (SAD), and as an aid to smoking cessation. •Summary (Drug B): Methocarbamol is a CNS depressant indicated with rest, physical therapy and other treatments to control the discomfort associated with various acute musculoskeletal conditions. Output: Central nervous system (CNS) depressants can cause sedation, falls, respiratory depression, coma, and death.2,3 The potential interaction between a CNS depressant and another CNS depressant drug due to synergistic effects is well documented in the literature, although the risk and severity of CNS depression vary from each drug. The subject and affected drugs are both CNS depressants that, when co-administered, may result in a more profound CNS depression. As the risk and severity of CNS depression resulting from the combined use of CNS depressants vary from each agent, each interaction between CNS depressants should be considered individually. The severity of the interaction is moderate.

Does Bupropion and Methohexital interact?

•Drug A: Bupropion •Drug B: Methohexital •Severity: MODERATE •Description: The risk or severity of CNS depression can be increased when Methohexital is combined with Bupropion. •Extended Description: Central nervous system (CNS) depressants can cause sedation, falls, respiratory depression, coma, and death.2,3 The potential interaction between a CNS depressant and another CNS depressant drug due to synergistic effects is well documented in the literature, although the risk and severity of CNS depression vary from each drug. The subject and affected drugs are both CNS depressants that, when co-administered, may result in a more profound CNS depression. As the risk and severity of CNS depression resulting from the combined use of CNS depressants vary from each agent, each interaction between CNS depressants should be considered individually. •Indication (Drug A): Bupropion is indicated for the treatment of major depressive disorder (MDD), seasonal affective disorder (SAD), and as an aid to smoking cessation. When used in combination with naltrexone as the marketed product ContraveⓇ, bupropion is indicated as an adjunct to a reduced-calorie diet and increased physical activity for chronic weight management in adults with an initial body mass index (BMI) of: 30 kg/m^2 or greater (obese) or 27 kg/m^2 or greater (overweight) in the presence of at least one weight-related comorbid condition (e.g., hypertension, type 2 diabetes mellitus, or dyslipidemia). Bupropion is also used off-label as a first-line treatment in patients with ADHD and comorbid bipolar disorder when used as an adjunct to mood stabilizers. •Indication (Drug B): Methohexital is indicated for use as an intravenous anaesthetic. It has also been commonly used to induce deep sedation. •Pharmacodynamics (Drug A): Bupropion is chemically unrelated to tricyclic, tetracyclic, selective serotonin re-uptake inhibitors, or other known antidepressant agents. Compared to classical tricyclic antidepressants, Bupropion is a relatively weak inhibitor of the neuronal uptake of norepinephrine and dopamine. In addition, Bupropion does not inhibit monoamine oxidase. Bupropion has been found to be essentially inactive at the serotonin transporter (SERT)(IC50 >10 000 nM), however both bupropion and its primary metabolite hydroxybupropion have been found to block the function of cation-selective serotonin type 3A receptors (5-HT3ARs). Bupropion produces dose-related central nervous system (CNS) stimulant effects in animals, as evidenced by increased locomotor activity, increased rates of responding in various schedule-controlled operant behaviour tasks, and, at high doses, induction of mild stereotyped behaviour. Due to these stimulant effects and selective activity at dopamine and norepinephrine receptors, bupropion has been identified as having an abuse potential. Bupropion has a similar structure to the controlled substance Cathinone, and has been identified as having mild amphetamine-like activity, particularly when inhaled or injected. Bupropion is also known to lower the seizure threshold, making any pre-existing seizure conditions a contraindication to its use. This risk is exacerbated when bupropion is combined with other drugs or substances that lower the seizure threshold, such as cocaine, or in clinical situations that would increase the risk of a seizure such as abrupt alcohol or benzodiazepine withdrawal. As norepinephrine has been shown to have anticonvulsant properties, bupropion's inhibitory effects on NET are thought to contribute to its pro-convulsant activity. Bupropion has been shown to increase blood pressure and pose a risk for exacerbation of unmanaged or pre-existing hypertension, however, clinical trials of bupropion in smokers with CVD have not identified an increased incidence of CV events including stroke or heart attack. In clinical trials, the mean increase in systolic blood pressure associated with the use of bupropion was found to be 1.3 mmHg. •Pharmacodynamics (Drug B): Methohexital, a barbiturate, is used for the induction of anesthesia prior to the use of other general anesthetic agents and for induction of anesthesia for short surgical, diagnostic, or therapeutic procedures associated with minimal painful stimuli. Little analgesia is conferred by barbiturates; their use in the presence of pain may result in excitation. •Mechanism of action (Drug A): Bupropion is a norepinephrine/dopamine-reuptake inhibitor (NDRI) that exerts its pharmacological effects by weakly inhibiting the enzymes involved in the uptake of the neurotransmitters norepinephrine and dopamine from the synaptic cleft, therefore prolonging their duration of action within the neuronal synapse and the downstream effects of these neurotransmitters. More specifically, bupropion binds to the norepinephrine transporter (NET) and the dopamine transporter (DAT). Bupropion was originally classified as an "atypical" antidepressant because it does not exert the same effects as the classical antidepressants such as Monoamine Oxidase Inhibitors (MAOIs), Tricyclic Antidepressants (TCAs), or Selective Serotonin Reuptake Inhibitors (SSRIs). While it has comparable effectiveness to typical first-line options for the treatment of depression such as SSRIs, bupropion is a unique option for the treatment of MDD as it lacks any clinically relevant serotonergic effects, typical of other mood medications, or any effects on histamine or adrenaline receptors. Lack of activity at these receptors results in a more tolerable side effect profile; bupropion is less likely to cause sexual side effects, sedation, or weight gain as compared to SSRIs or TCAs, for example. When used as an aid to smoking cessation, bupropion is thought to confer its anti-craving and anti-withdrawal effects by inhibiting dopamine reuptake, which is thought to be involved in the reward pathways associated with nicotine, and through the antagonism of the nicotinic acetylcholinergic receptor (AChR), thereby blunting the effects of nicotine. Furthermore, the stimulatory effects produced by bupropion in the central nervous system are similar to nicotine's effects, making low doses of bupropion a suitable option as a nicotine substitute. When used in combination with naltrexone in the marketed product ContraveⓇ for chronic weight management, the two components are thought to have effects on areas of the brain involved in the regulation of food intake. This includes the hypothalamus, which is involved in appetite regulation, and the mesolimbic dopamine circuit, which is involved in reward pathways. Studies have shown that the combined activity of bupropion and naltrexone increase the firing rate of hypothalamic pro-opiomelanocortin (POMC) neurons and blockade of opioid receptor-mediated POMC auto-inhibition, which are associated with a reduction in food intake and increased energy expenditure. This combination was also found to reduce food intake when injected directly into the ventral tegmental area of the mesolimbic circuit in mice, which is an area associated with the regulation of reward pathways. •Mechanism of action (Drug B): Methohexital binds at a distinct binding site associated with a Cl ionopore at the GABA A receptor, increasing the duration of time for which the Cl ionopore is open. The post-synaptic inhibitory effect of GABA in the thalamus is, therefore, prolonged. •Absorption (Drug A): Bupropion is currently available in 3 distinct, but bioequivalent formulations: immediate release (IR), sustained-release (SR), and extended-release (XL). Immediate Release Formulation In humans, following oral administration of bupropion hydrochloride tablets, peak plasma bupropion concentrations are usually achieved within 2 hours. IR formulations provide a short duration of action and are therefore generally dosed three times per day. Sustained Release Formulation In humans, following oral administration of bupropion hydrochloride sustained-release tablets (SR), peak plasma concentration (Cmax) of bupropion is usually achieved within 3 hours. SR formulations provide a 12-hour extended release of medication and are therefore generally dosed twice per day. Extended Release Formulation Following single oral administration of bupropion hydrochloride extended-release tablets (XL) to healthy volunteers, the median time to peak plasma concentrations for bupropion was approximately 5 hours. The presence of food did not affect the peak concentration or area under the curve of bupropion. XL formulations provide a 24-hour extended release of medication and are therefore generally dosed once per day/ In a trial comparing chronic dosing with bupropion hydrochloride extended-release tablets (SR) 150 mg twice daily to bupropion immediate-release formulation 100 mg 3 times daily, the steady state Cmax for bupropion after bupropion hydrochloride sustained-release tablets (SR) administration was approximately 85% of those achieved after bupropion immediate-release formulation administration. Exposure (AUC) to bupropion was equivalent for both formulations. Bioequivalence was also demonstrated for all three major active metabolites (i.e., hydroxybupropion, threohydrobupropion and erythrohydrobupropion) for both Cmax and AUC. Thus, at steady state, bupropion hydrochloride sustained-release tablets (SR) given twice daily, and the immediate-release formulation of bupropion given 3 times daily, are essentially bioequivalent for both bupropion and the 3 quantitatively important metabolites. Furthermore, in a study comparing 14-day dosing with bupropion hydrochloride extended-release tablets (XL), 300 mg once-daily to the immediate-release formulation of bupropion at 100 mg 3 times daily, equivalence was demonstrated for peak plasma concentration and area under the curve for bupropion and the three metabolites (hydroxybupropion, threohydrobupropion, and erythrohydrobupropion). Additionally, in a study comparing 14-day dosing with bupropion hydrochloride extended-release tablets (XL) 300 mg once daily to the sustained-release formulation of bupropion at 150 mg 2 times daily, equivalence was demonstrated for peak plasma concentration and area under the curve for bupropion and the three metabolites. Bupropion hydrochloride extended-release tablets (SR) can be taken with or without food. Bupropion Cmax and AUC were increased by 11% to 35% and 16% to 19%, respectively, when bupropion hydrochloride extended-release tablets (SR) was administered with food to healthy volunteers in three trials. The food effect is not considered clinically significant. Following a single-dose administration of bupropion hydrochloride extended-release tablets (SR) in humans, Cmax of bupropion's metabolite hydroxybupropion occurs approximately 6 hours post-dose and is approximately 10 times the peak level of the parent drug at steady state. The elimination half-life of hydroxybupropion is approximately 20 (±5) hours and its AUC at steady state is about 17 times that of bupropion. The times to peak concentrations for the erythrohydrobupropion and threohydrobupropion metabolites are similar to that of the hydroxybupropion metabolite. However, their elimination half-lives are longer, 33(±10) and 37 (±13) hours, respectively, and steady-state AUCs are 1.5 and 7 times that of bupropion, respectively. •Absorption (Drug B): The absolute bioavailability following rectal administration of methohexital is 17%. •Volume of distribution (Drug A): No volume of distribution available •Volume of distribution (Drug B): No volume of distribution available •Protein binding (Drug A): In vitro tests show that bupropion is 84% bound to human plasma proteins at concentrations up to 200 mcg per mL. The extent of protein binding of the hydroxybupropion metabolite is similar to that for bupropion, whereas the extent of protein binding of the threohydrobupropion metabolite is about half that seen with bupropion. •Protein binding (Drug B): 73% •Metabolism (Drug A): Bupropion is extensively metabolized in humans. Three metabolites are active: hydroxybupropion, which is formed via hydroxylation of the tert-butyl group of bupropion, and the amino-alcohol isomers, threohydrobupropion and erythrohydrobupropion, which are formed via reduction of the carbonyl group. In vitro findings suggest that CYP2B6 is the principal isoenzyme involved in the formation of hydroxybupropion, while cytochrome P450 enzymes are not involved in the formation of threohydrobupropion. Hydroxybupropion has been shown to have the same affinity as bupropion for the norepinephrine transporter (NET) but approximately 50% of its antidepressant activity despite reaching concentrations of ~10-fold higher than that of the parent drug. Oxidation of the bupropion side chain results in the formation of a glycine conjugate of meta-chlorobenzoic acid, which is then excreted as the major urinary metabolite. The potency and toxicity of the metabolites relative to bupropion have not been fully characterized. However, it has been demonstrated in an antidepressant screening test in mice that hydroxybupropion is one-half as potent as bupropion, while threohydrobupropion and erythrohydrobupropion are 5-fold less potent than bupropion. This may be of clinical importance because the plasma concentrations of the metabolites are as high as or higher than those of bupropion. Bupropion and its metabolites exhibit linear kinetics following chronic administration of 300 to 450 mg per day. •Metabolism (Drug B): Metabolism occurs in the liver through demethylation and oxidation. Side-chain oxidation is the most important biotransformation involved in termination of biologic activity. •Route of elimination (Drug A): Bupropion is extensively metabolized in humans. Oxidation of the bupropion side chain results in the formation of a glycine conjugate of metachlorobenzoic acid, which is then excreted as the major urinary metabolite. Following oral administration of 200 mg of 14C-bupropion in humans, 87% and 10% of the radioactive dose were recovered in the urine and feces, respectively. However, the fraction of the oral dose of bupropion excreted unchanged was only 0.5%, a finding consistent with the extensive metabolism of bupropion. •Route of elimination (Drug B): Excretion occurs via the kidneys through glomerular filtration. •Half-life (Drug A): 24 hours •Half-life (Drug B): 5.6 ± 2.7 minutes •Clearance (Drug A): No clearance available •Clearance (Drug B): No clearance available •Toxicity (Drug A): Symptoms of overdose include seizures, hallucinations, loss of consciousness, tachycardia, and cardiac arrest. •Toxicity (Drug B): The onset of toxicity following an overdose of intravenously administered methohexital will be within seconds of the infusion. If methohexital is administered rectally or is ingested, the onset of toxicity may be delayed. The manifestations of an ultrashort-acting barbiturate in overdose include central nervous system depression, respiratory depression, hypotension, loss of peripheral vascular resistance, and muscular hyperactivity ranging from twitching to convulsive-like movements. Other findings may include convulsions and allergic reactions. Following massive exposure to any barbiturate, pulmonary edema, circulatory collapse with loss of peripheral vascular tone, and cardiac arrest may occur. •Brand Names (Drug A): Aplenzin, Auvelity, Budeprion, Contrave, Forfivo, Wellbutrin, Zyban •Brand Names (Drug B): Brevital •Synonyms (Drug A): No synonyms listed •Synonyms (Drug B): Methohexital Methohexitalum Methohexitone Metohexital •Summary (Drug A): Bupropion is a norepinephrine and dopamine reuptake inhibitor used in the treatment of major depressive disorder (MDD), seasonal affective disorder (SAD), and as an aid to smoking cessation. •Summary (Drug B): Methohexital is an anesthetic used to induce deep sedation.

Central nervous system (CNS) depressants can cause sedation, falls, respiratory depression, coma, and death.2,3 The potential interaction between a CNS depressant and another CNS depressant drug due to synergistic effects is well documented in the literature, although the risk and severity of CNS depression vary from each drug. The subject and affected drugs are both CNS depressants that, when co-administered, may result in a more profound CNS depression. As the risk and severity of CNS depression resulting from the combined use of CNS depressants vary from each agent, each interaction between CNS depressants should be considered individually. The severity of the interaction is moderate.

Question: Does Bupropion and Methohexital interact? Information: •Drug A: Bupropion •Drug B: Methohexital •Severity: MODERATE •Description: The risk or severity of CNS depression can be increased when Methohexital is combined with Bupropion. •Extended Description: Central nervous system (CNS) depressants can cause sedation, falls, respiratory depression, coma, and death.2,3 The potential interaction between a CNS depressant and another CNS depressant drug due to synergistic effects is well documented in the literature, although the risk and severity of CNS depression vary from each drug. The subject and affected drugs are both CNS depressants that, when co-administered, may result in a more profound CNS depression. As the risk and severity of CNS depression resulting from the combined use of CNS depressants vary from each agent, each interaction between CNS depressants should be considered individually. •Indication (Drug A): Bupropion is indicated for the treatment of major depressive disorder (MDD), seasonal affective disorder (SAD), and as an aid to smoking cessation. When used in combination with naltrexone as the marketed product ContraveⓇ, bupropion is indicated as an adjunct to a reduced-calorie diet and increased physical activity for chronic weight management in adults with an initial body mass index (BMI) of: 30 kg/m^2 or greater (obese) or 27 kg/m^2 or greater (overweight) in the presence of at least one weight-related comorbid condition (e.g., hypertension, type 2 diabetes mellitus, or dyslipidemia). Bupropion is also used off-label as a first-line treatment in patients with ADHD and comorbid bipolar disorder when used as an adjunct to mood stabilizers. •Indication (Drug B): Methohexital is indicated for use as an intravenous anaesthetic. It has also been commonly used to induce deep sedation. •Pharmacodynamics (Drug A): Bupropion is chemically unrelated to tricyclic, tetracyclic, selective serotonin re-uptake inhibitors, or other known antidepressant agents. Compared to classical tricyclic antidepressants, Bupropion is a relatively weak inhibitor of the neuronal uptake of norepinephrine and dopamine. In addition, Bupropion does not inhibit monoamine oxidase. Bupropion has been found to be essentially inactive at the serotonin transporter (SERT)(IC50 >10 000 nM), however both bupropion and its primary metabolite hydroxybupropion have been found to block the function of cation-selective serotonin type 3A receptors (5-HT3ARs). Bupropion produces dose-related central nervous system (CNS) stimulant effects in animals, as evidenced by increased locomotor activity, increased rates of responding in various schedule-controlled operant behaviour tasks, and, at high doses, induction of mild stereotyped behaviour. Due to these stimulant effects and selective activity at dopamine and norepinephrine receptors, bupropion has been identified as having an abuse potential. Bupropion has a similar structure to the controlled substance Cathinone, and has been identified as having mild amphetamine-like activity, particularly when inhaled or injected. Bupropion is also known to lower the seizure threshold, making any pre-existing seizure conditions a contraindication to its use. This risk is exacerbated when bupropion is combined with other drugs or substances that lower the seizure threshold, such as cocaine, or in clinical situations that would increase the risk of a seizure such as abrupt alcohol or benzodiazepine withdrawal. As norepinephrine has been shown to have anticonvulsant properties, bupropion's inhibitory effects on NET are thought to contribute to its pro-convulsant activity. Bupropion has been shown to increase blood pressure and pose a risk for exacerbation of unmanaged or pre-existing hypertension, however, clinical trials of bupropion in smokers with CVD have not identified an increased incidence of CV events including stroke or heart attack. In clinical trials, the mean increase in systolic blood pressure associated with the use of bupropion was found to be 1.3 mmHg. •Pharmacodynamics (Drug B): Methohexital, a barbiturate, is used for the induction of anesthesia prior to the use of other general anesthetic agents and for induction of anesthesia for short surgical, diagnostic, or therapeutic procedures associated with minimal painful stimuli. Little analgesia is conferred by barbiturates; their use in the presence of pain may result in excitation. •Mechanism of action (Drug A): Bupropion is a norepinephrine/dopamine-reuptake inhibitor (NDRI) that exerts its pharmacological effects by weakly inhibiting the enzymes involved in the uptake of the neurotransmitters norepinephrine and dopamine from the synaptic cleft, therefore prolonging their duration of action within the neuronal synapse and the downstream effects of these neurotransmitters. More specifically, bupropion binds to the norepinephrine transporter (NET) and the dopamine transporter (DAT). Bupropion was originally classified as an "atypical" antidepressant because it does not exert the same effects as the classical antidepressants such as Monoamine Oxidase Inhibitors (MAOIs), Tricyclic Antidepressants (TCAs), or Selective Serotonin Reuptake Inhibitors (SSRIs). While it has comparable effectiveness to typical first-line options for the treatment of depression such as SSRIs, bupropion is a unique option for the treatment of MDD as it lacks any clinically relevant serotonergic effects, typical of other mood medications, or any effects on histamine or adrenaline receptors. Lack of activity at these receptors results in a more tolerable side effect profile; bupropion is less likely to cause sexual side effects, sedation, or weight gain as compared to SSRIs or TCAs, for example. When used as an aid to smoking cessation, bupropion is thought to confer its anti-craving and anti-withdrawal effects by inhibiting dopamine reuptake, which is thought to be involved in the reward pathways associated with nicotine, and through the antagonism of the nicotinic acetylcholinergic receptor (AChR), thereby blunting the effects of nicotine. Furthermore, the stimulatory effects produced by bupropion in the central nervous system are similar to nicotine's effects, making low doses of bupropion a suitable option as a nicotine substitute. When used in combination with naltrexone in the marketed product ContraveⓇ for chronic weight management, the two components are thought to have effects on areas of the brain involved in the regulation of food intake. This includes the hypothalamus, which is involved in appetite regulation, and the mesolimbic dopamine circuit, which is involved in reward pathways. Studies have shown that the combined activity of bupropion and naltrexone increase the firing rate of hypothalamic pro-opiomelanocortin (POMC) neurons and blockade of opioid receptor-mediated POMC auto-inhibition, which are associated with a reduction in food intake and increased energy expenditure. This combination was also found to reduce food intake when injected directly into the ventral tegmental area of the mesolimbic circuit in mice, which is an area associated with the regulation of reward pathways. •Mechanism of action (Drug B): Methohexital binds at a distinct binding site associated with a Cl ionopore at the GABA A receptor, increasing the duration of time for which the Cl ionopore is open. The post-synaptic inhibitory effect of GABA in the thalamus is, therefore, prolonged. •Absorption (Drug A): Bupropion is currently available in 3 distinct, but bioequivalent formulations: immediate release (IR), sustained-release (SR), and extended-release (XL). Immediate Release Formulation In humans, following oral administration of bupropion hydrochloride tablets, peak plasma bupropion concentrations are usually achieved within 2 hours. IR formulations provide a short duration of action and are therefore generally dosed three times per day. Sustained Release Formulation In humans, following oral administration of bupropion hydrochloride sustained-release tablets (SR), peak plasma concentration (Cmax) of bupropion is usually achieved within 3 hours. SR formulations provide a 12-hour extended release of medication and are therefore generally dosed twice per day. Extended Release Formulation Following single oral administration of bupropion hydrochloride extended-release tablets (XL) to healthy volunteers, the median time to peak plasma concentrations for bupropion was approximately 5 hours. The presence of food did not affect the peak concentration or area under the curve of bupropion. XL formulations provide a 24-hour extended release of medication and are therefore generally dosed once per day/ In a trial comparing chronic dosing with bupropion hydrochloride extended-release tablets (SR) 150 mg twice daily to bupropion immediate-release formulation 100 mg 3 times daily, the steady state Cmax for bupropion after bupropion hydrochloride sustained-release tablets (SR) administration was approximately 85% of those achieved after bupropion immediate-release formulation administration. Exposure (AUC) to bupropion was equivalent for both formulations. Bioequivalence was also demonstrated for all three major active metabolites (i.e., hydroxybupropion, threohydrobupropion and erythrohydrobupropion) for both Cmax and AUC. Thus, at steady state, bupropion hydrochloride sustained-release tablets (SR) given twice daily, and the immediate-release formulation of bupropion given 3 times daily, are essentially bioequivalent for both bupropion and the 3 quantitatively important metabolites. Furthermore, in a study comparing 14-day dosing with bupropion hydrochloride extended-release tablets (XL), 300 mg once-daily to the immediate-release formulation of bupropion at 100 mg 3 times daily, equivalence was demonstrated for peak plasma concentration and area under the curve for bupropion and the three metabolites (hydroxybupropion, threohydrobupropion, and erythrohydrobupropion). Additionally, in a study comparing 14-day dosing with bupropion hydrochloride extended-release tablets (XL) 300 mg once daily to the sustained-release formulation of bupropion at 150 mg 2 times daily, equivalence was demonstrated for peak plasma concentration and area under the curve for bupropion and the three metabolites. Bupropion hydrochloride extended-release tablets (SR) can be taken with or without food. Bupropion Cmax and AUC were increased by 11% to 35% and 16% to 19%, respectively, when bupropion hydrochloride extended-release tablets (SR) was administered with food to healthy volunteers in three trials. The food effect is not considered clinically significant. Following a single-dose administration of bupropion hydrochloride extended-release tablets (SR) in humans, Cmax of bupropion's metabolite hydroxybupropion occurs approximately 6 hours post-dose and is approximately 10 times the peak level of the parent drug at steady state. The elimination half-life of hydroxybupropion is approximately 20 (±5) hours and its AUC at steady state is about 17 times that of bupropion. The times to peak concentrations for the erythrohydrobupropion and threohydrobupropion metabolites are similar to that of the hydroxybupropion metabolite. However, their elimination half-lives are longer, 33(±10) and 37 (±13) hours, respectively, and steady-state AUCs are 1.5 and 7 times that of bupropion, respectively. •Absorption (Drug B): The absolute bioavailability following rectal administration of methohexital is 17%. •Volume of distribution (Drug A): No volume of distribution available •Volume of distribution (Drug B): No volume of distribution available •Protein binding (Drug A): In vitro tests show that bupropion is 84% bound to human plasma proteins at concentrations up to 200 mcg per mL. The extent of protein binding of the hydroxybupropion metabolite is similar to that for bupropion, whereas the extent of protein binding of the threohydrobupropion metabolite is about half that seen with bupropion. •Protein binding (Drug B): 73% •Metabolism (Drug A): Bupropion is extensively metabolized in humans. Three metabolites are active: hydroxybupropion, which is formed via hydroxylation of the tert-butyl group of bupropion, and the amino-alcohol isomers, threohydrobupropion and erythrohydrobupropion, which are formed via reduction of the carbonyl group. In vitro findings suggest that CYP2B6 is the principal isoenzyme involved in the formation of hydroxybupropion, while cytochrome P450 enzymes are not involved in the formation of threohydrobupropion. Hydroxybupropion has been shown to have the same affinity as bupropion for the norepinephrine transporter (NET) but approximately 50% of its antidepressant activity despite reaching concentrations of ~10-fold higher than that of the parent drug. Oxidation of the bupropion side chain results in the formation of a glycine conjugate of meta-chlorobenzoic acid, which is then excreted as the major urinary metabolite. The potency and toxicity of the metabolites relative to bupropion have not been fully characterized. However, it has been demonstrated in an antidepressant screening test in mice that hydroxybupropion is one-half as potent as bupropion, while threohydrobupropion and erythrohydrobupropion are 5-fold less potent than bupropion. This may be of clinical importance because the plasma concentrations of the metabolites are as high as or higher than those of bupropion. Bupropion and its metabolites exhibit linear kinetics following chronic administration of 300 to 450 mg per day. •Metabolism (Drug B): Metabolism occurs in the liver through demethylation and oxidation. Side-chain oxidation is the most important biotransformation involved in termination of biologic activity. •Route of elimination (Drug A): Bupropion is extensively metabolized in humans. Oxidation of the bupropion side chain results in the formation of a glycine conjugate of metachlorobenzoic acid, which is then excreted as the major urinary metabolite. Following oral administration of 200 mg of 14C-bupropion in humans, 87% and 10% of the radioactive dose were recovered in the urine and feces, respectively. However, the fraction of the oral dose of bupropion excreted unchanged was only 0.5%, a finding consistent with the extensive metabolism of bupropion. •Route of elimination (Drug B): Excretion occurs via the kidneys through glomerular filtration. •Half-life (Drug A): 24 hours •Half-life (Drug B): 5.6 ± 2.7 minutes •Clearance (Drug A): No clearance available •Clearance (Drug B): No clearance available •Toxicity (Drug A): Symptoms of overdose include seizures, hallucinations, loss of consciousness, tachycardia, and cardiac arrest. •Toxicity (Drug B): The onset of toxicity following an overdose of intravenously administered methohexital will be within seconds of the infusion. If methohexital is administered rectally or is ingested, the onset of toxicity may be delayed. The manifestations of an ultrashort-acting barbiturate in overdose include central nervous system depression, respiratory depression, hypotension, loss of peripheral vascular resistance, and muscular hyperactivity ranging from twitching to convulsive-like movements. Other findings may include convulsions and allergic reactions. Following massive exposure to any barbiturate, pulmonary edema, circulatory collapse with loss of peripheral vascular tone, and cardiac arrest may occur. •Brand Names (Drug A): Aplenzin, Auvelity, Budeprion, Contrave, Forfivo, Wellbutrin, Zyban •Brand Names (Drug B): Brevital •Synonyms (Drug A): No synonyms listed •Synonyms (Drug B): Methohexital Methohexitalum Methohexitone Metohexital •Summary (Drug A): Bupropion is a norepinephrine and dopamine reuptake inhibitor used in the treatment of major depressive disorder (MDD), seasonal affective disorder (SAD), and as an aid to smoking cessation. •Summary (Drug B): Methohexital is an anesthetic used to induce deep sedation. Output: Central nervous system (CNS) depressants can cause sedation, falls, respiratory depression, coma, and death.2,3 The potential interaction between a CNS depressant and another CNS depressant drug due to synergistic effects is well documented in the literature, although the risk and severity of CNS depression vary from each drug. The subject and affected drugs are both CNS depressants that, when co-administered, may result in a more profound CNS depression. As the risk and severity of CNS depression resulting from the combined use of CNS depressants vary from each agent, each interaction between CNS depressants should be considered individually. The severity of the interaction is moderate.

Does Bupropion and Methotrexate interact?

•Drug A: Bupropion •Drug B: Methotrexate •Severity: MINOR •Description: Methotrexate may decrease the excretion rate of Bupropion which could result in a higher serum level. •Extended Description: The subject drug is a nephrotoxic agent that may potentially impair renal function and decrease the excretion of drugs that mainly undergo renal excretion as the principal mode of clearance, such as the affected drug. Attenuated renal excretion of the affected drug may increase drug concentrations, leading to an elevated risk for drug-related adverse effects. •Indication (Drug A): Bupropion is indicated for the treatment of major depressive disorder (MDD), seasonal affective disorder (SAD), and as an aid to smoking cessation. When used in combination with naltrexone as the marketed product ContraveⓇ, bupropion is indicated as an adjunct to a reduced-calorie diet and increased physical activity for chronic weight management in adults with an initial body mass index (BMI) of: 30 kg/m^2 or greater (obese) or 27 kg/m^2 or greater (overweight) in the presence of at least one weight-related comorbid condition (e.g., hypertension, type 2 diabetes mellitus, or dyslipidemia). Bupropion is also used off-label as a first-line treatment in patients with ADHD and comorbid bipolar disorder when used as an adjunct to mood stabilizers. •Indication (Drug B): Methotrexate oral solution is indicated for pediatric acute lymphoblastic leukemia and pediatric polyarticular juvenile idiopathic arthritis. Methotrexate injections for subcutaneous use are indicated for severe active rheumatoid arthritis, polyarticular juvenile idiopathic arthritis and severe, recalcitrant, disabling psoriasis. It has also been approved by the EMA for the treatment of adult patients requiring systemic therapy for moderate-to-severe plaque psoriasis. Other formulations are indicated to treat gestational choriocarcinoma, chorioadenoma destruens, hydatiform mole, breast cancer, epidermoid cancer of the head and neck, advanced mycosis fungoides, lung cancer, and advanced non-Hodgkin's lymphoma. It is also used in the maintenance of acute lymphocytic leukemia. Methotrexate is also given before treatment with leucovorin to prolong relapse-free survival following surgical removal of a tumour in non-metastatic osteosarcoma. •Pharmacodynamics (Drug A): Bupropion is chemically unrelated to tricyclic, tetracyclic, selective serotonin re-uptake inhibitors, or other known antidepressant agents. Compared to classical tricyclic antidepressants, Bupropion is a relatively weak inhibitor of the neuronal uptake of norepinephrine and dopamine. In addition, Bupropion does not inhibit monoamine oxidase. Bupropion has been found to be essentially inactive at the serotonin transporter (SERT)(IC50 >10 000 nM), however both bupropion and its primary metabolite hydroxybupropion have been found to block the function of cation-selective serotonin type 3A receptors (5-HT3ARs). Bupropion produces dose-related central nervous system (CNS) stimulant effects in animals, as evidenced by increased locomotor activity, increased rates of responding in various schedule-controlled operant behaviour tasks, and, at high doses, induction of mild stereotyped behaviour. Due to these stimulant effects and selective activity at dopamine and norepinephrine receptors, bupropion has been identified as having an abuse potential. Bupropion has a similar structure to the controlled substance Cathinone, and has been identified as having mild amphetamine-like activity, particularly when inhaled or injected. Bupropion is also known to lower the seizure threshold, making any pre-existing seizure conditions a contraindication to its use. This risk is exacerbated when bupropion is combined with other drugs or substances that lower the seizure threshold, such as cocaine, or in clinical situations that would increase the risk of a seizure such as abrupt alcohol or benzodiazepine withdrawal. As norepinephrine has been shown to have anticonvulsant properties, bupropion's inhibitory effects on NET are thought to contribute to its pro-convulsant activity. Bupropion has been shown to increase blood pressure and pose a risk for exacerbation of unmanaged or pre-existing hypertension, however, clinical trials of bupropion in smokers with CVD have not identified an increased incidence of CV events including stroke or heart attack. In clinical trials, the mean increase in systolic blood pressure associated with the use of bupropion was found to be 1.3 mmHg. •Pharmacodynamics (Drug B): Methotrexate inhibits enzymes responsible for nucleotide synthesis which prevents cell division and leads to anti-inflammatory actions. It has a long duration of action and is generally given to patients once weekly. Methotrexate has a narrow therapeutic index. Do not take methotrexate daily. •Mechanism of action (Drug A): Bupropion is a norepinephrine/dopamine-reuptake inhibitor (NDRI) that exerts its pharmacological effects by weakly inhibiting the enzymes involved in the uptake of the neurotransmitters norepinephrine and dopamine from the synaptic cleft, therefore prolonging their duration of action within the neuronal synapse and the downstream effects of these neurotransmitters. More specifically, bupropion binds to the norepinephrine transporter (NET) and the dopamine transporter (DAT). Bupropion was originally classified as an "atypical" antidepressant because it does not exert the same effects as the classical antidepressants such as Monoamine Oxidase Inhibitors (MAOIs), Tricyclic Antidepressants (TCAs), or Selective Serotonin Reuptake Inhibitors (SSRIs). While it has comparable effectiveness to typical first-line options for the treatment of depression such as SSRIs, bupropion is a unique option for the treatment of MDD as it lacks any clinically relevant serotonergic effects, typical of other mood medications, or any effects on histamine or adrenaline receptors. Lack of activity at these receptors results in a more tolerable side effect profile; bupropion is less likely to cause sexual side effects, sedation, or weight gain as compared to SSRIs or TCAs, for example. When used as an aid to smoking cessation, bupropion is thought to confer its anti-craving and anti-withdrawal effects by inhibiting dopamine reuptake, which is thought to be involved in the reward pathways associated with nicotine, and through the antagonism of the nicotinic acetylcholinergic receptor (AChR), thereby blunting the effects of nicotine. Furthermore, the stimulatory effects produced by bupropion in the central nervous system are similar to nicotine's effects, making low doses of bupropion a suitable option as a nicotine substitute. When used in combination with naltrexone in the marketed product ContraveⓇ for chronic weight management, the two components are thought to have effects on areas of the brain involved in the regulation of food intake. This includes the hypothalamus, which is involved in appetite regulation, and the mesolimbic dopamine circuit, which is involved in reward pathways. Studies have shown that the combined activity of bupropion and naltrexone increase the firing rate of hypothalamic pro-opiomelanocortin (POMC) neurons and blockade of opioid receptor-mediated POMC auto-inhibition, which are associated with a reduction in food intake and increased energy expenditure. This combination was also found to reduce food intake when injected directly into the ventral tegmental area of the mesolimbic circuit in mice, which is an area associated with the regulation of reward pathways. •Mechanism of action (Drug B): Methotrexate enters tissues and is converted to a methotrexate polyglutamate by folylpolyglutamate. Methotrexate's mechanism of action is due to its inhibition of enzymes responsible for nucleotide synthesis including dihydrofolate reductase, thymidylate synthase, aminoimidazole caboxamide ribonucleotide transformylase (AICART), and amido phosphoribosyltransferase. Inhibtion of nucleotide synthesis prevents cell division. In rheumatoid arthritis, methotrexate polyglutamates inhibit AICART more than methotrexate. This inhibition leads to accumulation of AICART ribonucleotide, which inhibits adenosine deaminase, leading to an accumulation of adenosine triphosphate and adenosine in the extracellular space, stimulating adenosine receptors, leading to anti-inflammatory action. •Absorption (Drug A): Bupropion is currently available in 3 distinct, but bioequivalent formulations: immediate release (IR), sustained-release (SR), and extended-release (XL). Immediate Release Formulation In humans, following oral administration of bupropion hydrochloride tablets, peak plasma bupropion concentrations are usually achieved within 2 hours. IR formulations provide a short duration of action and are therefore generally dosed three times per day. Sustained Release Formulation In humans, following oral administration of bupropion hydrochloride sustained-release tablets (SR), peak plasma concentration (Cmax) of bupropion is usually achieved within 3 hours. SR formulations provide a 12-hour extended release of medication and are therefore generally dosed twice per day. Extended Release Formulation Following single oral administration of bupropion hydrochloride extended-release tablets (XL) to healthy volunteers, the median time to peak plasma concentrations for bupropion was approximately 5 hours. The presence of food did not affect the peak concentration or area under the curve of bupropion. XL formulations provide a 24-hour extended release of medication and are therefore generally dosed once per day/ In a trial comparing chronic dosing with bupropion hydrochloride extended-release tablets (SR) 150 mg twice daily to bupropion immediate-release formulation 100 mg 3 times daily, the steady state Cmax for bupropion after bupropion hydrochloride sustained-release tablets (SR) administration was approximately 85% of those achieved after bupropion immediate-release formulation administration. Exposure (AUC) to bupropion was equivalent for both formulations. Bioequivalence was also demonstrated for all three major active metabolites (i.e., hydroxybupropion, threohydrobupropion and erythrohydrobupropion) for both Cmax and AUC. Thus, at steady state, bupropion hydrochloride sustained-release tablets (SR) given twice daily, and the immediate-release formulation of bupropion given 3 times daily, are essentially bioequivalent for both bupropion and the 3 quantitatively important metabolites. Furthermore, in a study comparing 14-day dosing with bupropion hydrochloride extended-release tablets (XL), 300 mg once-daily to the immediate-release formulation of bupropion at 100 mg 3 times daily, equivalence was demonstrated for peak plasma concentration and area under the curve for bupropion and the three metabolites (hydroxybupropion, threohydrobupropion, and erythrohydrobupropion). Additionally, in a study comparing 14-day dosing with bupropion hydrochloride extended-release tablets (XL) 300 mg once daily to the sustained-release formulation of bupropion at 150 mg 2 times daily, equivalence was demonstrated for peak plasma concentration and area under the curve for bupropion and the three metabolites. Bupropion hydrochloride extended-release tablets (SR) can be taken with or without food. Bupropion Cmax and AUC were increased by 11% to 35% and 16% to 19%, respectively, when bupropion hydrochloride extended-release tablets (SR) was administered with food to healthy volunteers in three trials. The food effect is not considered clinically significant. Following a single-dose administration of bupropion hydrochloride extended-release tablets (SR) in humans, Cmax of bupropion's metabolite hydroxybupropion occurs approximately 6 hours post-dose and is approximately 10 times the peak level of the parent drug at steady state. The elimination half-life of hydroxybupropion is approximately 20 (±5) hours and its AUC at steady state is about 17 times that of bupropion. The times to peak concentrations for the erythrohydrobupropion and threohydrobupropion metabolites are similar to that of the hydroxybupropion metabolite. However, their elimination half-lives are longer, 33(±10) and 37 (±13) hours, respectively, and steady-state AUCs are 1.5 and 7 times that of bupropion, respectively. •Absorption (Drug B): Methotrexate has a bioavailability of 64-90%, though this decreases at oral doses above 25mg due to saturation of the carrier mediated transport of methotrexate.. Methotrexate has a T max of 1 to 2 hours. oral doses of 10-15µg reach serum levels of 0.01-0.1µM. •Volume of distribution (Drug A): No volume of distribution available •Volume of distribution (Drug B): The volume of distribution of methotrexate at steady state is approximately 1L/kg. •Protein binding (Drug A): In vitro tests show that bupropion is 84% bound to human plasma proteins at concentrations up to 200 mcg per mL. The extent of protein binding of the hydroxybupropion metabolite is similar to that for bupropion, whereas the extent of protein binding of the threohydrobupropion metabolite is about half that seen with bupropion. •Protein binding (Drug B): Methotrexate is 46.5-54% bound to plasma proteins. •Metabolism (Drug A): Bupropion is extensively metabolized in humans. Three metabolites are active: hydroxybupropion, which is formed via hydroxylation of the tert-butyl group of bupropion, and the amino-alcohol isomers, threohydrobupropion and erythrohydrobupropion, which are formed via reduction of the carbonyl group. In vitro findings suggest that CYP2B6 is the principal isoenzyme involved in the formation of hydroxybupropion, while cytochrome P450 enzymes are not involved in the formation of threohydrobupropion. Hydroxybupropion has been shown to have the same affinity as bupropion for the norepinephrine transporter (NET) but approximately 50% of its antidepressant activity despite reaching concentrations of ~10-fold higher than that of the parent drug. Oxidation of the bupropion side chain results in the formation of a glycine conjugate of meta-chlorobenzoic acid, which is then excreted as the major urinary metabolite. The potency and toxicity of the metabolites relative to bupropion have not been fully characterized. However, it has been demonstrated in an antidepressant screening test in mice that hydroxybupropion is one-half as potent as bupropion, while threohydrobupropion and erythrohydrobupropion are 5-fold less potent than bupropion. This may be of clinical importance because the plasma concentrations of the metabolites are as high as or higher than those of bupropion. Bupropion and its metabolites exhibit linear kinetics following chronic administration of 300 to 450 mg per day. •Metabolism (Drug B): Methotrexate is metabolized by folylpolyglutamate synthase to methotrexate polyglutamate in the liver as well as in tissues. Gamma-glutamyl hydrolase hydrolyzes the glutamyl chains of methotrexate polyglutamates converting them back to methotrexate. A small amount of methotrexate is also converted to 7-hydroxymethotrexate. •Route of elimination (Drug A): Bupropion is extensively metabolized in humans. Oxidation of the bupropion side chain results in the formation of a glycine conjugate of metachlorobenzoic acid, which is then excreted as the major urinary metabolite. Following oral administration of 200 mg of 14C-bupropion in humans, 87% and 10% of the radioactive dose were recovered in the urine and feces, respectively. However, the fraction of the oral dose of bupropion excreted unchanged was only 0.5%, a finding consistent with the extensive metabolism of bupropion. •Route of elimination (Drug B): Methotrexate is >80% excreted as the unchanged drug and approximately 3% as the 7-hydroxylated metabolite. Methotrexate is primarily excreted in the urine with 8.7-26% of an intravenous dose appearing in the bile. •Half-life (Drug A): 24 hours •Half-life (Drug B): The half life of low dose methotrexate is 3 to 10 hours in adults. The half life for high dose methotrexate is 8 to 15 hours. Pediatric patients taking methotrexate for acute lymphoblastic anemia experience a terminal half life of 0.7 to 5.8 hours. Pediatric patients taking methotrexate for juvenile idiopathic arthritis experience a half life of 0.9 to 2.3 hours. •Clearance (Drug A): No clearance available •Clearance (Drug B): Methotrexate clearance varies widely between patients and decreases with increasing doses. Currently, predicting clearance of methotrexate is difficult and exceedingly high serum levels of methotrexate can still occur when all precautions are taken. •Toxicity (Drug A): Symptoms of overdose include seizures, hallucinations, loss of consciousness, tachycardia, and cardiac arrest. •Toxicity (Drug B): The oral LD 50 in rats is 135mg/kg and in mice is 146mg/kg. Symptoms of overdose include hematologic and gastrointestinal reactions like leukopenia, thombocytopenia, anemia, pancytopenia, bone marrow suppression, mucositis, stomatitis, oral ulceration, nausea, vomiting, gastrointestinal ulceration, and gastrointestinal bleeding. In the event of an overdose, patients should be treated with glucarpidase and not be given leucovorin for 2 hours before or after glucarpidase. •Brand Names (Drug A): Aplenzin, Auvelity, Budeprion, Contrave, Forfivo, Wellbutrin, Zyban •Brand Names (Drug B): Metoject, Nordimet, Otrexup, Rasuvo, Reditrex, Trexall, Xatmep •Synonyms (Drug A): No synonyms listed •Synonyms (Drug B): Amethopterin Methotrexat Méthotrexate Methotrexate Methotrexatum Metotrexato •Summary (Drug A): Bupropion is a norepinephrine and dopamine reuptake inhibitor used in the treatment of major depressive disorder (MDD), seasonal affective disorder (SAD), and as an aid to smoking cessation. •Summary (Drug B): Methotrexate is an antineoplastic agent used the treatment of a wide variety of cancers as well as severe psoriasis, severe rheumatoid arthritis, and juvenile rheumatoid arthritis.

The subject drug is a nephrotoxic agent that may potentially impair renal function and decrease the excretion of drugs that mainly undergo renal excretion as the principal mode of clearance, such as the affected drug. Attenuated renal excretion of the affected drug may increase drug concentrations, leading to an elevated risk for drug-related adverse effects. The severity of the interaction is minor.

Question: Does Bupropion and Methotrexate interact? Information: •Drug A: Bupropion •Drug B: Methotrexate •Severity: MINOR •Description: Methotrexate may decrease the excretion rate of Bupropion which could result in a higher serum level. •Extended Description: The subject drug is a nephrotoxic agent that may potentially impair renal function and decrease the excretion of drugs that mainly undergo renal excretion as the principal mode of clearance, such as the affected drug. Attenuated renal excretion of the affected drug may increase drug concentrations, leading to an elevated risk for drug-related adverse effects. •Indication (Drug A): Bupropion is indicated for the treatment of major depressive disorder (MDD), seasonal affective disorder (SAD), and as an aid to smoking cessation. When used in combination with naltrexone as the marketed product ContraveⓇ, bupropion is indicated as an adjunct to a reduced-calorie diet and increased physical activity for chronic weight management in adults with an initial body mass index (BMI) of: 30 kg/m^2 or greater (obese) or 27 kg/m^2 or greater (overweight) in the presence of at least one weight-related comorbid condition (e.g., hypertension, type 2 diabetes mellitus, or dyslipidemia). Bupropion is also used off-label as a first-line treatment in patients with ADHD and comorbid bipolar disorder when used as an adjunct to mood stabilizers. •Indication (Drug B): Methotrexate oral solution is indicated for pediatric acute lymphoblastic leukemia and pediatric polyarticular juvenile idiopathic arthritis. Methotrexate injections for subcutaneous use are indicated for severe active rheumatoid arthritis, polyarticular juvenile idiopathic arthritis and severe, recalcitrant, disabling psoriasis. It has also been approved by the EMA for the treatment of adult patients requiring systemic therapy for moderate-to-severe plaque psoriasis. Other formulations are indicated to treat gestational choriocarcinoma, chorioadenoma destruens, hydatiform mole, breast cancer, epidermoid cancer of the head and neck, advanced mycosis fungoides, lung cancer, and advanced non-Hodgkin's lymphoma. It is also used in the maintenance of acute lymphocytic leukemia. Methotrexate is also given before treatment with leucovorin to prolong relapse-free survival following surgical removal of a tumour in non-metastatic osteosarcoma. •Pharmacodynamics (Drug A): Bupropion is chemically unrelated to tricyclic, tetracyclic, selective serotonin re-uptake inhibitors, or other known antidepressant agents. Compared to classical tricyclic antidepressants, Bupropion is a relatively weak inhibitor of the neuronal uptake of norepinephrine and dopamine. In addition, Bupropion does not inhibit monoamine oxidase. Bupropion has been found to be essentially inactive at the serotonin transporter (SERT)(IC50 >10 000 nM), however both bupropion and its primary metabolite hydroxybupropion have been found to block the function of cation-selective serotonin type 3A receptors (5-HT3ARs). Bupropion produces dose-related central nervous system (CNS) stimulant effects in animals, as evidenced by increased locomotor activity, increased rates of responding in various schedule-controlled operant behaviour tasks, and, at high doses, induction of mild stereotyped behaviour. Due to these stimulant effects and selective activity at dopamine and norepinephrine receptors, bupropion has been identified as having an abuse potential. Bupropion has a similar structure to the controlled substance Cathinone, and has been identified as having mild amphetamine-like activity, particularly when inhaled or injected. Bupropion is also known to lower the seizure threshold, making any pre-existing seizure conditions a contraindication to its use. This risk is exacerbated when bupropion is combined with other drugs or substances that lower the seizure threshold, such as cocaine, or in clinical situations that would increase the risk of a seizure such as abrupt alcohol or benzodiazepine withdrawal. As norepinephrine has been shown to have anticonvulsant properties, bupropion's inhibitory effects on NET are thought to contribute to its pro-convulsant activity. Bupropion has been shown to increase blood pressure and pose a risk for exacerbation of unmanaged or pre-existing hypertension, however, clinical trials of bupropion in smokers with CVD have not identified an increased incidence of CV events including stroke or heart attack. In clinical trials, the mean increase in systolic blood pressure associated with the use of bupropion was found to be 1.3 mmHg. •Pharmacodynamics (Drug B): Methotrexate inhibits enzymes responsible for nucleotide synthesis which prevents cell division and leads to anti-inflammatory actions. It has a long duration of action and is generally given to patients once weekly. Methotrexate has a narrow therapeutic index. Do not take methotrexate daily. •Mechanism of action (Drug A): Bupropion is a norepinephrine/dopamine-reuptake inhibitor (NDRI) that exerts its pharmacological effects by weakly inhibiting the enzymes involved in the uptake of the neurotransmitters norepinephrine and dopamine from the synaptic cleft, therefore prolonging their duration of action within the neuronal synapse and the downstream effects of these neurotransmitters. More specifically, bupropion binds to the norepinephrine transporter (NET) and the dopamine transporter (DAT). Bupropion was originally classified as an "atypical" antidepressant because it does not exert the same effects as the classical antidepressants such as Monoamine Oxidase Inhibitors (MAOIs), Tricyclic Antidepressants (TCAs), or Selective Serotonin Reuptake Inhibitors (SSRIs). While it has comparable effectiveness to typical first-line options for the treatment of depression such as SSRIs, bupropion is a unique option for the treatment of MDD as it lacks any clinically relevant serotonergic effects, typical of other mood medications, or any effects on histamine or adrenaline receptors. Lack of activity at these receptors results in a more tolerable side effect profile; bupropion is less likely to cause sexual side effects, sedation, or weight gain as compared to SSRIs or TCAs, for example. When used as an aid to smoking cessation, bupropion is thought to confer its anti-craving and anti-withdrawal effects by inhibiting dopamine reuptake, which is thought to be involved in the reward pathways associated with nicotine, and through the antagonism of the nicotinic acetylcholinergic receptor (AChR), thereby blunting the effects of nicotine. Furthermore, the stimulatory effects produced by bupropion in the central nervous system are similar to nicotine's effects, making low doses of bupropion a suitable option as a nicotine substitute. When used in combination with naltrexone in the marketed product ContraveⓇ for chronic weight management, the two components are thought to have effects on areas of the brain involved in the regulation of food intake. This includes the hypothalamus, which is involved in appetite regulation, and the mesolimbic dopamine circuit, which is involved in reward pathways. Studies have shown that the combined activity of bupropion and naltrexone increase the firing rate of hypothalamic pro-opiomelanocortin (POMC) neurons and blockade of opioid receptor-mediated POMC auto-inhibition, which are associated with a reduction in food intake and increased energy expenditure. This combination was also found to reduce food intake when injected directly into the ventral tegmental area of the mesolimbic circuit in mice, which is an area associated with the regulation of reward pathways. •Mechanism of action (Drug B): Methotrexate enters tissues and is converted to a methotrexate polyglutamate by folylpolyglutamate. Methotrexate's mechanism of action is due to its inhibition of enzymes responsible for nucleotide synthesis including dihydrofolate reductase, thymidylate synthase, aminoimidazole caboxamide ribonucleotide transformylase (AICART), and amido phosphoribosyltransferase. Inhibtion of nucleotide synthesis prevents cell division. In rheumatoid arthritis, methotrexate polyglutamates inhibit AICART more than methotrexate. This inhibition leads to accumulation of AICART ribonucleotide, which inhibits adenosine deaminase, leading to an accumulation of adenosine triphosphate and adenosine in the extracellular space, stimulating adenosine receptors, leading to anti-inflammatory action. •Absorption (Drug A): Bupropion is currently available in 3 distinct, but bioequivalent formulations: immediate release (IR), sustained-release (SR), and extended-release (XL). Immediate Release Formulation In humans, following oral administration of bupropion hydrochloride tablets, peak plasma bupropion concentrations are usually achieved within 2 hours. IR formulations provide a short duration of action and are therefore generally dosed three times per day. Sustained Release Formulation In humans, following oral administration of bupropion hydrochloride sustained-release tablets (SR), peak plasma concentration (Cmax) of bupropion is usually achieved within 3 hours. SR formulations provide a 12-hour extended release of medication and are therefore generally dosed twice per day. Extended Release Formulation Following single oral administration of bupropion hydrochloride extended-release tablets (XL) to healthy volunteers, the median time to peak plasma concentrations for bupropion was approximately 5 hours. The presence of food did not affect the peak concentration or area under the curve of bupropion. XL formulations provide a 24-hour extended release of medication and are therefore generally dosed once per day/ In a trial comparing chronic dosing with bupropion hydrochloride extended-release tablets (SR) 150 mg twice daily to bupropion immediate-release formulation 100 mg 3 times daily, the steady state Cmax for bupropion after bupropion hydrochloride sustained-release tablets (SR) administration was approximately 85% of those achieved after bupropion immediate-release formulation administration. Exposure (AUC) to bupropion was equivalent for both formulations. Bioequivalence was also demonstrated for all three major active metabolites (i.e., hydroxybupropion, threohydrobupropion and erythrohydrobupropion) for both Cmax and AUC. Thus, at steady state, bupropion hydrochloride sustained-release tablets (SR) given twice daily, and the immediate-release formulation of bupropion given 3 times daily, are essentially bioequivalent for both bupropion and the 3 quantitatively important metabolites. Furthermore, in a study comparing 14-day dosing with bupropion hydrochloride extended-release tablets (XL), 300 mg once-daily to the immediate-release formulation of bupropion at 100 mg 3 times daily, equivalence was demonstrated for peak plasma concentration and area under the curve for bupropion and the three metabolites (hydroxybupropion, threohydrobupropion, and erythrohydrobupropion). Additionally, in a study comparing 14-day dosing with bupropion hydrochloride extended-release tablets (XL) 300 mg once daily to the sustained-release formulation of bupropion at 150 mg 2 times daily, equivalence was demonstrated for peak plasma concentration and area under the curve for bupropion and the three metabolites. Bupropion hydrochloride extended-release tablets (SR) can be taken with or without food. Bupropion Cmax and AUC were increased by 11% to 35% and 16% to 19%, respectively, when bupropion hydrochloride extended-release tablets (SR) was administered with food to healthy volunteers in three trials. The food effect is not considered clinically significant. Following a single-dose administration of bupropion hydrochloride extended-release tablets (SR) in humans, Cmax of bupropion's metabolite hydroxybupropion occurs approximately 6 hours post-dose and is approximately 10 times the peak level of the parent drug at steady state. The elimination half-life of hydroxybupropion is approximately 20 (±5) hours and its AUC at steady state is about 17 times that of bupropion. The times to peak concentrations for the erythrohydrobupropion and threohydrobupropion metabolites are similar to that of the hydroxybupropion metabolite. However, their elimination half-lives are longer, 33(±10) and 37 (±13) hours, respectively, and steady-state AUCs are 1.5 and 7 times that of bupropion, respectively. •Absorption (Drug B): Methotrexate has a bioavailability of 64-90%, though this decreases at oral doses above 25mg due to saturation of the carrier mediated transport of methotrexate.. Methotrexate has a T max of 1 to 2 hours. oral doses of 10-15µg reach serum levels of 0.01-0.1µM. •Volume of distribution (Drug A): No volume of distribution available •Volume of distribution (Drug B): The volume of distribution of methotrexate at steady state is approximately 1L/kg. •Protein binding (Drug A): In vitro tests show that bupropion is 84% bound to human plasma proteins at concentrations up to 200 mcg per mL. The extent of protein binding of the hydroxybupropion metabolite is similar to that for bupropion, whereas the extent of protein binding of the threohydrobupropion metabolite is about half that seen with bupropion. •Protein binding (Drug B): Methotrexate is 46.5-54% bound to plasma proteins. •Metabolism (Drug A): Bupropion is extensively metabolized in humans. Three metabolites are active: hydroxybupropion, which is formed via hydroxylation of the tert-butyl group of bupropion, and the amino-alcohol isomers, threohydrobupropion and erythrohydrobupropion, which are formed via reduction of the carbonyl group. In vitro findings suggest that CYP2B6 is the principal isoenzyme involved in the formation of hydroxybupropion, while cytochrome P450 enzymes are not involved in the formation of threohydrobupropion. Hydroxybupropion has been shown to have the same affinity as bupropion for the norepinephrine transporter (NET) but approximately 50% of its antidepressant activity despite reaching concentrations of ~10-fold higher than that of the parent drug. Oxidation of the bupropion side chain results in the formation of a glycine conjugate of meta-chlorobenzoic acid, which is then excreted as the major urinary metabolite. The potency and toxicity of the metabolites relative to bupropion have not been fully characterized. However, it has been demonstrated in an antidepressant screening test in mice that hydroxybupropion is one-half as potent as bupropion, while threohydrobupropion and erythrohydrobupropion are 5-fold less potent than bupropion. This may be of clinical importance because the plasma concentrations of the metabolites are as high as or higher than those of bupropion. Bupropion and its metabolites exhibit linear kinetics following chronic administration of 300 to 450 mg per day. •Metabolism (Drug B): Methotrexate is metabolized by folylpolyglutamate synthase to methotrexate polyglutamate in the liver as well as in tissues. Gamma-glutamyl hydrolase hydrolyzes the glutamyl chains of methotrexate polyglutamates converting them back to methotrexate. A small amount of methotrexate is also converted to 7-hydroxymethotrexate. •Route of elimination (Drug A): Bupropion is extensively metabolized in humans. Oxidation of the bupropion side chain results in the formation of a glycine conjugate of metachlorobenzoic acid, which is then excreted as the major urinary metabolite. Following oral administration of 200 mg of 14C-bupropion in humans, 87% and 10% of the radioactive dose were recovered in the urine and feces, respectively. However, the fraction of the oral dose of bupropion excreted unchanged was only 0.5%, a finding consistent with the extensive metabolism of bupropion. •Route of elimination (Drug B): Methotrexate is >80% excreted as the unchanged drug and approximately 3% as the 7-hydroxylated metabolite. Methotrexate is primarily excreted in the urine with 8.7-26% of an intravenous dose appearing in the bile. •Half-life (Drug A): 24 hours •Half-life (Drug B): The half life of low dose methotrexate is 3 to 10 hours in adults. The half life for high dose methotrexate is 8 to 15 hours. Pediatric patients taking methotrexate for acute lymphoblastic anemia experience a terminal half life of 0.7 to 5.8 hours. Pediatric patients taking methotrexate for juvenile idiopathic arthritis experience a half life of 0.9 to 2.3 hours. •Clearance (Drug A): No clearance available •Clearance (Drug B): Methotrexate clearance varies widely between patients and decreases with increasing doses. Currently, predicting clearance of methotrexate is difficult and exceedingly high serum levels of methotrexate can still occur when all precautions are taken. •Toxicity (Drug A): Symptoms of overdose include seizures, hallucinations, loss of consciousness, tachycardia, and cardiac arrest. •Toxicity (Drug B): The oral LD 50 in rats is 135mg/kg and in mice is 146mg/kg. Symptoms of overdose include hematologic and gastrointestinal reactions like leukopenia, thombocytopenia, anemia, pancytopenia, bone marrow suppression, mucositis, stomatitis, oral ulceration, nausea, vomiting, gastrointestinal ulceration, and gastrointestinal bleeding. In the event of an overdose, patients should be treated with glucarpidase and not be given leucovorin for 2 hours before or after glucarpidase. •Brand Names (Drug A): Aplenzin, Auvelity, Budeprion, Contrave, Forfivo, Wellbutrin, Zyban •Brand Names (Drug B): Metoject, Nordimet, Otrexup, Rasuvo, Reditrex, Trexall, Xatmep •Synonyms (Drug A): No synonyms listed •Synonyms (Drug B): Amethopterin Methotrexat Méthotrexate Methotrexate Methotrexatum Metotrexato •Summary (Drug A): Bupropion is a norepinephrine and dopamine reuptake inhibitor used in the treatment of major depressive disorder (MDD), seasonal affective disorder (SAD), and as an aid to smoking cessation. •Summary (Drug B): Methotrexate is an antineoplastic agent used the treatment of a wide variety of cancers as well as severe psoriasis, severe rheumatoid arthritis, and juvenile rheumatoid arthritis. Output: The subject drug is a nephrotoxic agent that may potentially impair renal function and decrease the excretion of drugs that mainly undergo renal excretion as the principal mode of clearance, such as the affected drug. Attenuated renal excretion of the affected drug may increase drug concentrations, leading to an elevated risk for drug-related adverse effects. The severity of the interaction is minor.

Does Bupropion and Methotrimeprazine interact?

•Drug A: Bupropion •Drug B: Methotrimeprazine •Severity: MODERATE •Description: Bupropion may increase the central nervous system depressant (CNS depressant) activities of Methotrimeprazine. •Extended Description: The use of central nervous system depressants may potentiate the CNS depressant effects of methotrimeprazine, due to additive pharmacological effects. •Indication (Drug A): Bupropion is indicated for the treatment of major depressive disorder (MDD), seasonal affective disorder (SAD), and as an aid to smoking cessation. When used in combination with naltrexone as the marketed product ContraveⓇ, bupropion is indicated as an adjunct to a reduced-calorie diet and increased physical activity for chronic weight management in adults with an initial body mass index (BMI) of: 30 kg/m^2 or greater (obese) or 27 kg/m^2 or greater (overweight) in the presence of at least one weight-related comorbid condition (e.g., hypertension, type 2 diabetes mellitus, or dyslipidemia). Bupropion is also used off-label as a first-line treatment in patients with ADHD and comorbid bipolar disorder when used as an adjunct to mood stabilizers. •Indication (Drug B): For the treatment of psychosis, particular those of schizophrenia, and manic phases of bipolar disorder. •Pharmacodynamics (Drug A): Bupropion is chemically unrelated to tricyclic, tetracyclic, selective serotonin re-uptake inhibitors, or other known antidepressant agents. Compared to classical tricyclic antidepressants, Bupropion is a relatively weak inhibitor of the neuronal uptake of norepinephrine and dopamine. In addition, Bupropion does not inhibit monoamine oxidase. Bupropion has been found to be essentially inactive at the serotonin transporter (SERT)(IC50 >10 000 nM), however both bupropion and its primary metabolite hydroxybupropion have been found to block the function of cation-selective serotonin type 3A receptors (5-HT3ARs). Bupropion produces dose-related central nervous system (CNS) stimulant effects in animals, as evidenced by increased locomotor activity, increased rates of responding in various schedule-controlled operant behaviour tasks, and, at high doses, induction of mild stereotyped behaviour. Due to these stimulant effects and selective activity at dopamine and norepinephrine receptors, bupropion has been identified as having an abuse potential. Bupropion has a similar structure to the controlled substance Cathinone, and has been identified as having mild amphetamine-like activity, particularly when inhaled or injected. Bupropion is also known to lower the seizure threshold, making any pre-existing seizure conditions a contraindication to its use. This risk is exacerbated when bupropion is combined with other drugs or substances that lower the seizure threshold, such as cocaine, or in clinical situations that would increase the risk of a seizure such as abrupt alcohol or benzodiazepine withdrawal. As norepinephrine has been shown to have anticonvulsant properties, bupropion's inhibitory effects on NET are thought to contribute to its pro-convulsant activity. Bupropion has been shown to increase blood pressure and pose a risk for exacerbation of unmanaged or pre-existing hypertension, however, clinical trials of bupropion in smokers with CVD have not identified an increased incidence of CV events including stroke or heart attack. In clinical trials, the mean increase in systolic blood pressure associated with the use of bupropion was found to be 1.3 mmHg. •Pharmacodynamics (Drug B): Methotrimeprazine is a phenothiazine with pharmacological activity similar to that of both chlorpromazine and promethazine. It has the histamine-antagonist properties of the antihistamines together with central nervous system effects resembling those of chlorpromazine. (From Martindale, The Extra Pharmacopoeia, 30th ed, p604) •Mechanism of action (Drug A): Bupropion is a norepinephrine/dopamine-reuptake inhibitor (NDRI) that exerts its pharmacological effects by weakly inhibiting the enzymes involved in the uptake of the neurotransmitters norepinephrine and dopamine from the synaptic cleft, therefore prolonging their duration of action within the neuronal synapse and the downstream effects of these neurotransmitters. More specifically, bupropion binds to the norepinephrine transporter (NET) and the dopamine transporter (DAT). Bupropion was originally classified as an "atypical" antidepressant because it does not exert the same effects as the classical antidepressants such as Monoamine Oxidase Inhibitors (MAOIs), Tricyclic Antidepressants (TCAs), or Selective Serotonin Reuptake Inhibitors (SSRIs). While it has comparable effectiveness to typical first-line options for the treatment of depression such as SSRIs, bupropion is a unique option for the treatment of MDD as it lacks any clinically relevant serotonergic effects, typical of other mood medications, or any effects on histamine or adrenaline receptors. Lack of activity at these receptors results in a more tolerable side effect profile; bupropion is less likely to cause sexual side effects, sedation, or weight gain as compared to SSRIs or TCAs, for example. When used as an aid to smoking cessation, bupropion is thought to confer its anti-craving and anti-withdrawal effects by inhibiting dopamine reuptake, which is thought to be involved in the reward pathways associated with nicotine, and through the antagonism of the nicotinic acetylcholinergic receptor (AChR), thereby blunting the effects of nicotine. Furthermore, the stimulatory effects produced by bupropion in the central nervous system are similar to nicotine's effects, making low doses of bupropion a suitable option as a nicotine substitute. When used in combination with naltrexone in the marketed product ContraveⓇ for chronic weight management, the two components are thought to have effects on areas of the brain involved in the regulation of food intake. This includes the hypothalamus, which is involved in appetite regulation, and the mesolimbic dopamine circuit, which is involved in reward pathways. Studies have shown that the combined activity of bupropion and naltrexone increase the firing rate of hypothalamic pro-opiomelanocortin (POMC) neurons and blockade of opioid receptor-mediated POMC auto-inhibition, which are associated with a reduction in food intake and increased energy expenditure. This combination was also found to reduce food intake when injected directly into the ventral tegmental area of the mesolimbic circuit in mice, which is an area associated with the regulation of reward pathways. •Mechanism of action (Drug B): Methotrimeprazine's antipsychotic effect is largely due to its antagonism of dopamine receptors in the brain. In addition, its binding to 5HT2 receptors may also play a role. •Absorption (Drug A): Bupropion is currently available in 3 distinct, but bioequivalent formulations: immediate release (IR), sustained-release (SR), and extended-release (XL). Immediate Release Formulation In humans, following oral administration of bupropion hydrochloride tablets, peak plasma bupropion concentrations are usually achieved within 2 hours. IR formulations provide a short duration of action and are therefore generally dosed three times per day. Sustained Release Formulation In humans, following oral administration of bupropion hydrochloride sustained-release tablets (SR), peak plasma concentration (Cmax) of bupropion is usually achieved within 3 hours. SR formulations provide a 12-hour extended release of medication and are therefore generally dosed twice per day. Extended Release Formulation Following single oral administration of bupropion hydrochloride extended-release tablets (XL) to healthy volunteers, the median time to peak plasma concentrations for bupropion was approximately 5 hours. The presence of food did not affect the peak concentration or area under the curve of bupropion. XL formulations provide a 24-hour extended release of medication and are therefore generally dosed once per day/ In a trial comparing chronic dosing with bupropion hydrochloride extended-release tablets (SR) 150 mg twice daily to bupropion immediate-release formulation 100 mg 3 times daily, the steady state Cmax for bupropion after bupropion hydrochloride sustained-release tablets (SR) administration was approximately 85% of those achieved after bupropion immediate-release formulation administration. Exposure (AUC) to bupropion was equivalent for both formulations. Bioequivalence was also demonstrated for all three major active metabolites (i.e., hydroxybupropion, threohydrobupropion and erythrohydrobupropion) for both Cmax and AUC. Thus, at steady state, bupropion hydrochloride sustained-release tablets (SR) given twice daily, and the immediate-release formulation of bupropion given 3 times daily, are essentially bioequivalent for both bupropion and the 3 quantitatively important metabolites. Furthermore, in a study comparing 14-day dosing with bupropion hydrochloride extended-release tablets (XL), 300 mg once-daily to the immediate-release formulation of bupropion at 100 mg 3 times daily, equivalence was demonstrated for peak plasma concentration and area under the curve for bupropion and the three metabolites (hydroxybupropion, threohydrobupropion, and erythrohydrobupropion). Additionally, in a study comparing 14-day dosing with bupropion hydrochloride extended-release tablets (XL) 300 mg once daily to the sustained-release formulation of bupropion at 150 mg 2 times daily, equivalence was demonstrated for peak plasma concentration and area under the curve for bupropion and the three metabolites. Bupropion hydrochloride extended-release tablets (SR) can be taken with or without food. Bupropion Cmax and AUC were increased by 11% to 35% and 16% to 19%, respectively, when bupropion hydrochloride extended-release tablets (SR) was administered with food to healthy volunteers in three trials. The food effect is not considered clinically significant. Following a single-dose administration of bupropion hydrochloride extended-release tablets (SR) in humans, Cmax of bupropion's metabolite hydroxybupropion occurs approximately 6 hours post-dose and is approximately 10 times the peak level of the parent drug at steady state. The elimination half-life of hydroxybupropion is approximately 20 (±5) hours and its AUC at steady state is about 17 times that of bupropion. The times to peak concentrations for the erythrohydrobupropion and threohydrobupropion metabolites are similar to that of the hydroxybupropion metabolite. However, their elimination half-lives are longer, 33(±10) and 37 (±13) hours, respectively, and steady-state AUCs are 1.5 and 7 times that of bupropion, respectively. •Absorption (Drug B): Methotrimeprazine has an incomplete oral bioavailability, because it undergoes considerable first-pass-metabolism in the liver. Oral bioavailability is approximately 50 to 60%. •Volume of distribution (Drug A): No volume of distribution available •Volume of distribution (Drug B): No volume of distribution available •Protein binding (Drug A): In vitro tests show that bupropion is 84% bound to human plasma proteins at concentrations up to 200 mcg per mL. The extent of protein binding of the hydroxybupropion metabolite is similar to that for bupropion, whereas the extent of protein binding of the threohydrobupropion metabolite is about half that seen with bupropion. •Protein binding (Drug B): No protein binding available •Metabolism (Drug A): Bupropion is extensively metabolized in humans. Three metabolites are active: hydroxybupropion, which is formed via hydroxylation of the tert-butyl group of bupropion, and the amino-alcohol isomers, threohydrobupropion and erythrohydrobupropion, which are formed via reduction of the carbonyl group. In vitro findings suggest that CYP2B6 is the principal isoenzyme involved in the formation of hydroxybupropion, while cytochrome P450 enzymes are not involved in the formation of threohydrobupropion. Hydroxybupropion has been shown to have the same affinity as bupropion for the norepinephrine transporter (NET) but approximately 50% of its antidepressant activity despite reaching concentrations of ~10-fold higher than that of the parent drug. Oxidation of the bupropion side chain results in the formation of a glycine conjugate of meta-chlorobenzoic acid, which is then excreted as the major urinary metabolite. The potency and toxicity of the metabolites relative to bupropion have not been fully characterized. However, it has been demonstrated in an antidepressant screening test in mice that hydroxybupropion is one-half as potent as bupropion, while threohydrobupropion and erythrohydrobupropion are 5-fold less potent than bupropion. This may be of clinical importance because the plasma concentrations of the metabolites are as high as or higher than those of bupropion. Bupropion and its metabolites exhibit linear kinetics following chronic administration of 300 to 450 mg per day. •Metabolism (Drug B): Hepatic. Methotrimeprazine is metabolized in the liver and degraded to a sulfoxid-, a glucuronid- and a demethyl-moiety. •Route of elimination (Drug A): Bupropion is extensively metabolized in humans. Oxidation of the bupropion side chain results in the formation of a glycine conjugate of metachlorobenzoic acid, which is then excreted as the major urinary metabolite. Following oral administration of 200 mg of 14C-bupropion in humans, 87% and 10% of the radioactive dose were recovered in the urine and feces, respectively. However, the fraction of the oral dose of bupropion excreted unchanged was only 0.5%, a finding consistent with the extensive metabolism of bupropion. •Route of elimination (Drug B): No route of elimination available •Half-life (Drug A): 24 hours •Half-life (Drug B): Approximately 20 hours. •Clearance (Drug A): No clearance available •Clearance (Drug B): No clearance available •Toxicity (Drug A): Symptoms of overdose include seizures, hallucinations, loss of consciousness, tachycardia, and cardiac arrest. •Toxicity (Drug B): Symptoms of overdose include convulsions, spastic movements, and coma. •Brand Names (Drug A): Aplenzin, Auvelity, Budeprion, Contrave, Forfivo, Wellbutrin, Zyban •Brand Names (Drug B): Nozinan •Synonyms (Drug A): No synonyms listed •Synonyms (Drug B): 2-Methoxytrimeprazine Levomepromazina Levomepromazine Lévomépromazine Levomepromazinum Methotrimeprazine •Summary (Drug A): Bupropion is a norepinephrine and dopamine reuptake inhibitor used in the treatment of major depressive disorder (MDD), seasonal affective disorder (SAD), and as an aid to smoking cessation. •Summary (Drug B): Methotrimeprazine is a phenothiazine used in the management of psychosis, particular those of schizophrenia, and manic phases of bipolar disorder.

The use of central nervous system depressants may potentiate the CNS depressant effects of methotrimeprazine, due to additive pharmacological effects. The severity of the interaction is moderate.

Question: Does Bupropion and Methotrimeprazine interact? Information: •Drug A: Bupropion •Drug B: Methotrimeprazine •Severity: MODERATE •Description: Bupropion may increase the central nervous system depressant (CNS depressant) activities of Methotrimeprazine. •Extended Description: The use of central nervous system depressants may potentiate the CNS depressant effects of methotrimeprazine, due to additive pharmacological effects. •Indication (Drug A): Bupropion is indicated for the treatment of major depressive disorder (MDD), seasonal affective disorder (SAD), and as an aid to smoking cessation. When used in combination with naltrexone as the marketed product ContraveⓇ, bupropion is indicated as an adjunct to a reduced-calorie diet and increased physical activity for chronic weight management in adults with an initial body mass index (BMI) of: 30 kg/m^2 or greater (obese) or 27 kg/m^2 or greater (overweight) in the presence of at least one weight-related comorbid condition (e.g., hypertension, type 2 diabetes mellitus, or dyslipidemia). Bupropion is also used off-label as a first-line treatment in patients with ADHD and comorbid bipolar disorder when used as an adjunct to mood stabilizers. •Indication (Drug B): For the treatment of psychosis, particular those of schizophrenia, and manic phases of bipolar disorder. •Pharmacodynamics (Drug A): Bupropion is chemically unrelated to tricyclic, tetracyclic, selective serotonin re-uptake inhibitors, or other known antidepressant agents. Compared to classical tricyclic antidepressants, Bupropion is a relatively weak inhibitor of the neuronal uptake of norepinephrine and dopamine. In addition, Bupropion does not inhibit monoamine oxidase. Bupropion has been found to be essentially inactive at the serotonin transporter (SERT)(IC50 >10 000 nM), however both bupropion and its primary metabolite hydroxybupropion have been found to block the function of cation-selective serotonin type 3A receptors (5-HT3ARs). Bupropion produces dose-related central nervous system (CNS) stimulant effects in animals, as evidenced by increased locomotor activity, increased rates of responding in various schedule-controlled operant behaviour tasks, and, at high doses, induction of mild stereotyped behaviour. Due to these stimulant effects and selective activity at dopamine and norepinephrine receptors, bupropion has been identified as having an abuse potential. Bupropion has a similar structure to the controlled substance Cathinone, and has been identified as having mild amphetamine-like activity, particularly when inhaled or injected. Bupropion is also known to lower the seizure threshold, making any pre-existing seizure conditions a contraindication to its use. This risk is exacerbated when bupropion is combined with other drugs or substances that lower the seizure threshold, such as cocaine, or in clinical situations that would increase the risk of a seizure such as abrupt alcohol or benzodiazepine withdrawal. As norepinephrine has been shown to have anticonvulsant properties, bupropion's inhibitory effects on NET are thought to contribute to its pro-convulsant activity. Bupropion has been shown to increase blood pressure and pose a risk for exacerbation of unmanaged or pre-existing hypertension, however, clinical trials of bupropion in smokers with CVD have not identified an increased incidence of CV events including stroke or heart attack. In clinical trials, the mean increase in systolic blood pressure associated with the use of bupropion was found to be 1.3 mmHg. •Pharmacodynamics (Drug B): Methotrimeprazine is a phenothiazine with pharmacological activity similar to that of both chlorpromazine and promethazine. It has the histamine-antagonist properties of the antihistamines together with central nervous system effects resembling those of chlorpromazine. (From Martindale, The Extra Pharmacopoeia, 30th ed, p604) •Mechanism of action (Drug A): Bupropion is a norepinephrine/dopamine-reuptake inhibitor (NDRI) that exerts its pharmacological effects by weakly inhibiting the enzymes involved in the uptake of the neurotransmitters norepinephrine and dopamine from the synaptic cleft, therefore prolonging their duration of action within the neuronal synapse and the downstream effects of these neurotransmitters. More specifically, bupropion binds to the norepinephrine transporter (NET) and the dopamine transporter (DAT). Bupropion was originally classified as an "atypical" antidepressant because it does not exert the same effects as the classical antidepressants such as Monoamine Oxidase Inhibitors (MAOIs), Tricyclic Antidepressants (TCAs), or Selective Serotonin Reuptake Inhibitors (SSRIs). While it has comparable effectiveness to typical first-line options for the treatment of depression such as SSRIs, bupropion is a unique option for the treatment of MDD as it lacks any clinically relevant serotonergic effects, typical of other mood medications, or any effects on histamine or adrenaline receptors. Lack of activity at these receptors results in a more tolerable side effect profile; bupropion is less likely to cause sexual side effects, sedation, or weight gain as compared to SSRIs or TCAs, for example. When used as an aid to smoking cessation, bupropion is thought to confer its anti-craving and anti-withdrawal effects by inhibiting dopamine reuptake, which is thought to be involved in the reward pathways associated with nicotine, and through the antagonism of the nicotinic acetylcholinergic receptor (AChR), thereby blunting the effects of nicotine. Furthermore, the stimulatory effects produced by bupropion in the central nervous system are similar to nicotine's effects, making low doses of bupropion a suitable option as a nicotine substitute. When used in combination with naltrexone in the marketed product ContraveⓇ for chronic weight management, the two components are thought to have effects on areas of the brain involved in the regulation of food intake. This includes the hypothalamus, which is involved in appetite regulation, and the mesolimbic dopamine circuit, which is involved in reward pathways. Studies have shown that the combined activity of bupropion and naltrexone increase the firing rate of hypothalamic pro-opiomelanocortin (POMC) neurons and blockade of opioid receptor-mediated POMC auto-inhibition, which are associated with a reduction in food intake and increased energy expenditure. This combination was also found to reduce food intake when injected directly into the ventral tegmental area of the mesolimbic circuit in mice, which is an area associated with the regulation of reward pathways. •Mechanism of action (Drug B): Methotrimeprazine's antipsychotic effect is largely due to its antagonism of dopamine receptors in the brain. In addition, its binding to 5HT2 receptors may also play a role. •Absorption (Drug A): Bupropion is currently available in 3 distinct, but bioequivalent formulations: immediate release (IR), sustained-release (SR), and extended-release (XL). Immediate Release Formulation In humans, following oral administration of bupropion hydrochloride tablets, peak plasma bupropion concentrations are usually achieved within 2 hours. IR formulations provide a short duration of action and are therefore generally dosed three times per day. Sustained Release Formulation In humans, following oral administration of bupropion hydrochloride sustained-release tablets (SR), peak plasma concentration (Cmax) of bupropion is usually achieved within 3 hours. SR formulations provide a 12-hour extended release of medication and are therefore generally dosed twice per day. Extended Release Formulation Following single oral administration of bupropion hydrochloride extended-release tablets (XL) to healthy volunteers, the median time to peak plasma concentrations for bupropion was approximately 5 hours. The presence of food did not affect the peak concentration or area under the curve of bupropion. XL formulations provide a 24-hour extended release of medication and are therefore generally dosed once per day/ In a trial comparing chronic dosing with bupropion hydrochloride extended-release tablets (SR) 150 mg twice daily to bupropion immediate-release formulation 100 mg 3 times daily, the steady state Cmax for bupropion after bupropion hydrochloride sustained-release tablets (SR) administration was approximately 85% of those achieved after bupropion immediate-release formulation administration. Exposure (AUC) to bupropion was equivalent for both formulations. Bioequivalence was also demonstrated for all three major active metabolites (i.e., hydroxybupropion, threohydrobupropion and erythrohydrobupropion) for both Cmax and AUC. Thus, at steady state, bupropion hydrochloride sustained-release tablets (SR) given twice daily, and the immediate-release formulation of bupropion given 3 times daily, are essentially bioequivalent for both bupropion and the 3 quantitatively important metabolites. Furthermore, in a study comparing 14-day dosing with bupropion hydrochloride extended-release tablets (XL), 300 mg once-daily to the immediate-release formulation of bupropion at 100 mg 3 times daily, equivalence was demonstrated for peak plasma concentration and area under the curve for bupropion and the three metabolites (hydroxybupropion, threohydrobupropion, and erythrohydrobupropion). Additionally, in a study comparing 14-day dosing with bupropion hydrochloride extended-release tablets (XL) 300 mg once daily to the sustained-release formulation of bupropion at 150 mg 2 times daily, equivalence was demonstrated for peak plasma concentration and area under the curve for bupropion and the three metabolites. Bupropion hydrochloride extended-release tablets (SR) can be taken with or without food. Bupropion Cmax and AUC were increased by 11% to 35% and 16% to 19%, respectively, when bupropion hydrochloride extended-release tablets (SR) was administered with food to healthy volunteers in three trials. The food effect is not considered clinically significant. Following a single-dose administration of bupropion hydrochloride extended-release tablets (SR) in humans, Cmax of bupropion's metabolite hydroxybupropion occurs approximately 6 hours post-dose and is approximately 10 times the peak level of the parent drug at steady state. The elimination half-life of hydroxybupropion is approximately 20 (±5) hours and its AUC at steady state is about 17 times that of bupropion. The times to peak concentrations for the erythrohydrobupropion and threohydrobupropion metabolites are similar to that of the hydroxybupropion metabolite. However, their elimination half-lives are longer, 33(±10) and 37 (±13) hours, respectively, and steady-state AUCs are 1.5 and 7 times that of bupropion, respectively. •Absorption (Drug B): Methotrimeprazine has an incomplete oral bioavailability, because it undergoes considerable first-pass-metabolism in the liver. Oral bioavailability is approximately 50 to 60%. •Volume of distribution (Drug A): No volume of distribution available •Volume of distribution (Drug B): No volume of distribution available •Protein binding (Drug A): In vitro tests show that bupropion is 84% bound to human plasma proteins at concentrations up to 200 mcg per mL. The extent of protein binding of the hydroxybupropion metabolite is similar to that for bupropion, whereas the extent of protein binding of the threohydrobupropion metabolite is about half that seen with bupropion. •Protein binding (Drug B): No protein binding available •Metabolism (Drug A): Bupropion is extensively metabolized in humans. Three metabolites are active: hydroxybupropion, which is formed via hydroxylation of the tert-butyl group of bupropion, and the amino-alcohol isomers, threohydrobupropion and erythrohydrobupropion, which are formed via reduction of the carbonyl group. In vitro findings suggest that CYP2B6 is the principal isoenzyme involved in the formation of hydroxybupropion, while cytochrome P450 enzymes are not involved in the formation of threohydrobupropion. Hydroxybupropion has been shown to have the same affinity as bupropion for the norepinephrine transporter (NET) but approximately 50% of its antidepressant activity despite reaching concentrations of ~10-fold higher than that of the parent drug. Oxidation of the bupropion side chain results in the formation of a glycine conjugate of meta-chlorobenzoic acid, which is then excreted as the major urinary metabolite. The potency and toxicity of the metabolites relative to bupropion have not been fully characterized. However, it has been demonstrated in an antidepressant screening test in mice that hydroxybupropion is one-half as potent as bupropion, while threohydrobupropion and erythrohydrobupropion are 5-fold less potent than bupropion. This may be of clinical importance because the plasma concentrations of the metabolites are as high as or higher than those of bupropion. Bupropion and its metabolites exhibit linear kinetics following chronic administration of 300 to 450 mg per day. •Metabolism (Drug B): Hepatic. Methotrimeprazine is metabolized in the liver and degraded to a sulfoxid-, a glucuronid- and a demethyl-moiety. •Route of elimination (Drug A): Bupropion is extensively metabolized in humans. Oxidation of the bupropion side chain results in the formation of a glycine conjugate of metachlorobenzoic acid, which is then excreted as the major urinary metabolite. Following oral administration of 200 mg of 14C-bupropion in humans, 87% and 10% of the radioactive dose were recovered in the urine and feces, respectively. However, the fraction of the oral dose of bupropion excreted unchanged was only 0.5%, a finding consistent with the extensive metabolism of bupropion. •Route of elimination (Drug B): No route of elimination available •Half-life (Drug A): 24 hours •Half-life (Drug B): Approximately 20 hours. •Clearance (Drug A): No clearance available •Clearance (Drug B): No clearance available •Toxicity (Drug A): Symptoms of overdose include seizures, hallucinations, loss of consciousness, tachycardia, and cardiac arrest. •Toxicity (Drug B): Symptoms of overdose include convulsions, spastic movements, and coma. •Brand Names (Drug A): Aplenzin, Auvelity, Budeprion, Contrave, Forfivo, Wellbutrin, Zyban •Brand Names (Drug B): Nozinan •Synonyms (Drug A): No synonyms listed •Synonyms (Drug B): 2-Methoxytrimeprazine Levomepromazina Levomepromazine Lévomépromazine Levomepromazinum Methotrimeprazine •Summary (Drug A): Bupropion is a norepinephrine and dopamine reuptake inhibitor used in the treatment of major depressive disorder (MDD), seasonal affective disorder (SAD), and as an aid to smoking cessation. •Summary (Drug B): Methotrimeprazine is a phenothiazine used in the management of psychosis, particular those of schizophrenia, and manic phases of bipolar disorder. Output: The use of central nervous system depressants may potentiate the CNS depressant effects of methotrimeprazine, due to additive pharmacological effects. The severity of the interaction is moderate.

Does Bupropion and Methoxsalen interact?

•Drug A: Bupropion •Drug B: Methoxsalen •Severity: MINOR •Description: Methoxsalen may decrease the excretion rate of Bupropion which could result in a higher serum level. •Extended Description: The renal excretion of drugs is the overall result of a combination of kidney processes that include glomerular filtration, passive diffusion, tubular secretion, and tubular reabsorption. Since two of these mechanisms - tubular secretion and reabsorption - are saturable processes , they are consequently susceptible to competition between multiple substrates excreted by the kidneys. If two or more medications that are mainly renally excreted are co-administered, they may compete for renal elimination; there is a large likelihood that one agent may "out-compete" or saturate the renal excretion mechanisms before the other concomitantly administered agent(s) are excreted. As a result, the elimination of these other concurrently administered agents may be inhibited or otherwise delayed, which could lead to increases in their serum concentrations and the risk, incidence, and/or severity of adverse effects associated with the exposure to such drugs. •Indication (Drug A): Bupropion is indicated for the treatment of major depressive disorder (MDD), seasonal affective disorder (SAD), and as an aid to smoking cessation. When used in combination with naltrexone as the marketed product ContraveⓇ, bupropion is indicated as an adjunct to a reduced-calorie diet and increased physical activity for chronic weight management in adults with an initial body mass index (BMI) of: 30 kg/m^2 or greater (obese) or 27 kg/m^2 or greater (overweight) in the presence of at least one weight-related comorbid condition (e.g., hypertension, type 2 diabetes mellitus, or dyslipidemia). Bupropion is also used off-label as a first-line treatment in patients with ADHD and comorbid bipolar disorder when used as an adjunct to mood stabilizers. •Indication (Drug B): For the treatment of psoriasis and vitiligo •Pharmacodynamics (Drug A): Bupropion is chemically unrelated to tricyclic, tetracyclic, selective serotonin re-uptake inhibitors, or other known antidepressant agents. Compared to classical tricyclic antidepressants, Bupropion is a relatively weak inhibitor of the neuronal uptake of norepinephrine and dopamine. In addition, Bupropion does not inhibit monoamine oxidase. Bupropion has been found to be essentially inactive at the serotonin transporter (SERT)(IC50 >10 000 nM), however both bupropion and its primary metabolite hydroxybupropion have been found to block the function of cation-selective serotonin type 3A receptors (5-HT3ARs). Bupropion produces dose-related central nervous system (CNS) stimulant effects in animals, as evidenced by increased locomotor activity, increased rates of responding in various schedule-controlled operant behaviour tasks, and, at high doses, induction of mild stereotyped behaviour. Due to these stimulant effects and selective activity at dopamine and norepinephrine receptors, bupropion has been identified as having an abuse potential. Bupropion has a similar structure to the controlled substance Cathinone, and has been identified as having mild amphetamine-like activity, particularly when inhaled or injected. Bupropion is also known to lower the seizure threshold, making any pre-existing seizure conditions a contraindication to its use. This risk is exacerbated when bupropion is combined with other drugs or substances that lower the seizure threshold, such as cocaine, or in clinical situations that would increase the risk of a seizure such as abrupt alcohol or benzodiazepine withdrawal. As norepinephrine has been shown to have anticonvulsant properties, bupropion's inhibitory effects on NET are thought to contribute to its pro-convulsant activity. Bupropion has been shown to increase blood pressure and pose a risk for exacerbation of unmanaged or pre-existing hypertension, however, clinical trials of bupropion in smokers with CVD have not identified an increased incidence of CV events including stroke or heart attack. In clinical trials, the mean increase in systolic blood pressure associated with the use of bupropion was found to be 1.3 mmHg. •Pharmacodynamics (Drug B): Methoxsalen selectively inhibits the synthesis of deoxyribonucleic acid (DNA). The guanine and cytosine content correlates with the degree of Methoxsalen-induced cross-linking. At high concentrations of the drug, cellular RNA and protein synthesis are also suppressed. •Mechanism of action (Drug A): Bupropion is a norepinephrine/dopamine-reuptake inhibitor (NDRI) that exerts its pharmacological effects by weakly inhibiting the enzymes involved in the uptake of the neurotransmitters norepinephrine and dopamine from the synaptic cleft, therefore prolonging their duration of action within the neuronal synapse and the downstream effects of these neurotransmitters. More specifically, bupropion binds to the norepinephrine transporter (NET) and the dopamine transporter (DAT). Bupropion was originally classified as an "atypical" antidepressant because it does not exert the same effects as the classical antidepressants such as Monoamine Oxidase Inhibitors (MAOIs), Tricyclic Antidepressants (TCAs), or Selective Serotonin Reuptake Inhibitors (SSRIs). While it has comparable effectiveness to typical first-line options for the treatment of depression such as SSRIs, bupropion is a unique option for the treatment of MDD as it lacks any clinically relevant serotonergic effects, typical of other mood medications, or any effects on histamine or adrenaline receptors. Lack of activity at these receptors results in a more tolerable side effect profile; bupropion is less likely to cause sexual side effects, sedation, or weight gain as compared to SSRIs or TCAs, for example. When used as an aid to smoking cessation, bupropion is thought to confer its anti-craving and anti-withdrawal effects by inhibiting dopamine reuptake, which is thought to be involved in the reward pathways associated with nicotine, and through the antagonism of the nicotinic acetylcholinergic receptor (AChR), thereby blunting the effects of nicotine. Furthermore, the stimulatory effects produced by bupropion in the central nervous system are similar to nicotine's effects, making low doses of bupropion a suitable option as a nicotine substitute. When used in combination with naltrexone in the marketed product ContraveⓇ for chronic weight management, the two components are thought to have effects on areas of the brain involved in the regulation of food intake. This includes the hypothalamus, which is involved in appetite regulation, and the mesolimbic dopamine circuit, which is involved in reward pathways. Studies have shown that the combined activity of bupropion and naltrexone increase the firing rate of hypothalamic pro-opiomelanocortin (POMC) neurons and blockade of opioid receptor-mediated POMC auto-inhibition, which are associated with a reduction in food intake and increased energy expenditure. This combination was also found to reduce food intake when injected directly into the ventral tegmental area of the mesolimbic circuit in mice, which is an area associated with the regulation of reward pathways. •Mechanism of action (Drug B): After activation it binds preferentially to the guanine and cytosine moieties of DNA, leading to cross-linking of DNA, thus inhibiting DNA synthesis and function. •Absorption (Drug A): Bupropion is currently available in 3 distinct, but bioequivalent formulations: immediate release (IR), sustained-release (SR), and extended-release (XL). Immediate Release Formulation In humans, following oral administration of bupropion hydrochloride tablets, peak plasma bupropion concentrations are usually achieved within 2 hours. IR formulations provide a short duration of action and are therefore generally dosed three times per day. Sustained Release Formulation In humans, following oral administration of bupropion hydrochloride sustained-release tablets (SR), peak plasma concentration (Cmax) of bupropion is usually achieved within 3 hours. SR formulations provide a 12-hour extended release of medication and are therefore generally dosed twice per day. Extended Release Formulation Following single oral administration of bupropion hydrochloride extended-release tablets (XL) to healthy volunteers, the median time to peak plasma concentrations for bupropion was approximately 5 hours. The presence of food did not affect the peak concentration or area under the curve of bupropion. XL formulations provide a 24-hour extended release of medication and are therefore generally dosed once per day/ In a trial comparing chronic dosing with bupropion hydrochloride extended-release tablets (SR) 150 mg twice daily to bupropion immediate-release formulation 100 mg 3 times daily, the steady state Cmax for bupropion after bupropion hydrochloride sustained-release tablets (SR) administration was approximately 85% of those achieved after bupropion immediate-release formulation administration. Exposure (AUC) to bupropion was equivalent for both formulations. Bioequivalence was also demonstrated for all three major active metabolites (i.e., hydroxybupropion, threohydrobupropion and erythrohydrobupropion) for both Cmax and AUC. Thus, at steady state, bupropion hydrochloride sustained-release tablets (SR) given twice daily, and the immediate-release formulation of bupropion given 3 times daily, are essentially bioequivalent for both bupropion and the 3 quantitatively important metabolites. Furthermore, in a study comparing 14-day dosing with bupropion hydrochloride extended-release tablets (XL), 300 mg once-daily to the immediate-release formulation of bupropion at 100 mg 3 times daily, equivalence was demonstrated for peak plasma concentration and area under the curve for bupropion and the three metabolites (hydroxybupropion, threohydrobupropion, and erythrohydrobupropion). Additionally, in a study comparing 14-day dosing with bupropion hydrochloride extended-release tablets (XL) 300 mg once daily to the sustained-release formulation of bupropion at 150 mg 2 times daily, equivalence was demonstrated for peak plasma concentration and area under the curve for bupropion and the three metabolites. Bupropion hydrochloride extended-release tablets (SR) can be taken with or without food. Bupropion Cmax and AUC were increased by 11% to 35% and 16% to 19%, respectively, when bupropion hydrochloride extended-release tablets (SR) was administered with food to healthy volunteers in three trials. The food effect is not considered clinically significant. Following a single-dose administration of bupropion hydrochloride extended-release tablets (SR) in humans, Cmax of bupropion's metabolite hydroxybupropion occurs approximately 6 hours post-dose and is approximately 10 times the peak level of the parent drug at steady state. The elimination half-life of hydroxybupropion is approximately 20 (±5) hours and its AUC at steady state is about 17 times that of bupropion. The times to peak concentrations for the erythrohydrobupropion and threohydrobupropion metabolites are similar to that of the hydroxybupropion metabolite. However, their elimination half-lives are longer, 33(±10) and 37 (±13) hours, respectively, and steady-state AUCs are 1.5 and 7 times that of bupropion, respectively. •Absorption (Drug B): No absorption available •Volume of distribution (Drug A): No volume of distribution available •Volume of distribution (Drug B): No volume of distribution available •Protein binding (Drug A): In vitro tests show that bupropion is 84% bound to human plasma proteins at concentrations up to 200 mcg per mL. The extent of protein binding of the hydroxybupropion metabolite is similar to that for bupropion, whereas the extent of protein binding of the threohydrobupropion metabolite is about half that seen with bupropion. •Protein binding (Drug B): No protein binding available •Metabolism (Drug A): Bupropion is extensively metabolized in humans. Three metabolites are active: hydroxybupropion, which is formed via hydroxylation of the tert-butyl group of bupropion, and the amino-alcohol isomers, threohydrobupropion and erythrohydrobupropion, which are formed via reduction of the carbonyl group. In vitro findings suggest that CYP2B6 is the principal isoenzyme involved in the formation of hydroxybupropion, while cytochrome P450 enzymes are not involved in the formation of threohydrobupropion. Hydroxybupropion has been shown to have the same affinity as bupropion for the norepinephrine transporter (NET) but approximately 50% of its antidepressant activity despite reaching concentrations of ~10-fold higher than that of the parent drug. Oxidation of the bupropion side chain results in the formation of a glycine conjugate of meta-chlorobenzoic acid, which is then excreted as the major urinary metabolite. The potency and toxicity of the metabolites relative to bupropion have not been fully characterized. However, it has been demonstrated in an antidepressant screening test in mice that hydroxybupropion is one-half as potent as bupropion, while threohydrobupropion and erythrohydrobupropion are 5-fold less potent than bupropion. This may be of clinical importance because the plasma concentrations of the metabolites are as high as or higher than those of bupropion. Bupropion and its metabolites exhibit linear kinetics following chronic administration of 300 to 450 mg per day. •Metabolism (Drug B): No metabolism available •Route of elimination (Drug A): Bupropion is extensively metabolized in humans. Oxidation of the bupropion side chain results in the formation of a glycine conjugate of metachlorobenzoic acid, which is then excreted as the major urinary metabolite. Following oral administration of 200 mg of 14C-bupropion in humans, 87% and 10% of the radioactive dose were recovered in the urine and feces, respectively. However, the fraction of the oral dose of bupropion excreted unchanged was only 0.5%, a finding consistent with the extensive metabolism of bupropion. •Route of elimination (Drug B): In both mice and man, methoxsalen is rapidly metabolized. Approximately 95% of the drug is excreted as a series of metabolites in the urine within 24 hours (Pathak et al. 1977). •Half-life (Drug A): 24 hours •Half-life (Drug B): Approximately 2 hours •Clearance (Drug A): No clearance available •Clearance (Drug B): No clearance available •Toxicity (Drug A): Symptoms of overdose include seizures, hallucinations, loss of consciousness, tachycardia, and cardiac arrest. •Toxicity (Drug B): No toxicity available •Brand Names (Drug A): Aplenzin, Auvelity, Budeprion, Contrave, Forfivo, Wellbutrin, Zyban •Brand Names (Drug B): Oxsoralen, Uvadex •Synonyms (Drug A): No synonyms listed •Synonyms (Drug B): 8-Methoxyfuranocoumarin 8-methoxypsoralen 8-MOP 8-MP Ammoidin Methoxsalen Méthoxsalène Metoxaleno O-methylxanthotoxol Xanthotoxin Xanthotoxine •Summary (Drug A): Bupropion is a norepinephrine and dopamine reuptake inhibitor used in the treatment of major depressive disorder (MDD), seasonal affective disorder (SAD), and as an aid to smoking cessation. •Summary (Drug B): Methoxsalen is a furocoumarin used to treat psoriasis and vitiligo.

The renal excretion of drugs is the overall result of a combination of kidney processes that include glomerular filtration, passive diffusion, tubular secretion, and tubular reabsorption. Since two of these mechanisms - tubular secretion and reabsorption - are saturable processes , they are consequently susceptible to competition between multiple substrates excreted by the kidneys. If two or more medications that are mainly renally excreted are co-administered, they may compete for renal elimination; there is a large likelihood that one agent may "out-compete" or saturate the renal excretion mechanisms before the other concomitantly administered agent(s) are excreted. As a result, the elimination of these other concurrently administered agents may be inhibited or otherwise delayed, which could lead to increases in their serum concentrations and the risk, incidence, and/or severity of adverse effects associated with the exposure to such drugs. The severity of the interaction is minor.

Question: Does Bupropion and Methoxsalen interact? Information: •Drug A: Bupropion •Drug B: Methoxsalen •Severity: MINOR •Description: Methoxsalen may decrease the excretion rate of Bupropion which could result in a higher serum level. •Extended Description: The renal excretion of drugs is the overall result of a combination of kidney processes that include glomerular filtration, passive diffusion, tubular secretion, and tubular reabsorption. Since two of these mechanisms - tubular secretion and reabsorption - are saturable processes , they are consequently susceptible to competition between multiple substrates excreted by the kidneys. If two or more medications that are mainly renally excreted are co-administered, they may compete for renal elimination; there is a large likelihood that one agent may "out-compete" or saturate the renal excretion mechanisms before the other concomitantly administered agent(s) are excreted. As a result, the elimination of these other concurrently administered agents may be inhibited or otherwise delayed, which could lead to increases in their serum concentrations and the risk, incidence, and/or severity of adverse effects associated with the exposure to such drugs. •Indication (Drug A): Bupropion is indicated for the treatment of major depressive disorder (MDD), seasonal affective disorder (SAD), and as an aid to smoking cessation. When used in combination with naltrexone as the marketed product ContraveⓇ, bupropion is indicated as an adjunct to a reduced-calorie diet and increased physical activity for chronic weight management in adults with an initial body mass index (BMI) of: 30 kg/m^2 or greater (obese) or 27 kg/m^2 or greater (overweight) in the presence of at least one weight-related comorbid condition (e.g., hypertension, type 2 diabetes mellitus, or dyslipidemia). Bupropion is also used off-label as a first-line treatment in patients with ADHD and comorbid bipolar disorder when used as an adjunct to mood stabilizers. •Indication (Drug B): For the treatment of psoriasis and vitiligo •Pharmacodynamics (Drug A): Bupropion is chemically unrelated to tricyclic, tetracyclic, selective serotonin re-uptake inhibitors, or other known antidepressant agents. Compared to classical tricyclic antidepressants, Bupropion is a relatively weak inhibitor of the neuronal uptake of norepinephrine and dopamine. In addition, Bupropion does not inhibit monoamine oxidase. Bupropion has been found to be essentially inactive at the serotonin transporter (SERT)(IC50 >10 000 nM), however both bupropion and its primary metabolite hydroxybupropion have been found to block the function of cation-selective serotonin type 3A receptors (5-HT3ARs). Bupropion produces dose-related central nervous system (CNS) stimulant effects in animals, as evidenced by increased locomotor activity, increased rates of responding in various schedule-controlled operant behaviour tasks, and, at high doses, induction of mild stereotyped behaviour. Due to these stimulant effects and selective activity at dopamine and norepinephrine receptors, bupropion has been identified as having an abuse potential. Bupropion has a similar structure to the controlled substance Cathinone, and has been identified as having mild amphetamine-like activity, particularly when inhaled or injected. Bupropion is also known to lower the seizure threshold, making any pre-existing seizure conditions a contraindication to its use. This risk is exacerbated when bupropion is combined with other drugs or substances that lower the seizure threshold, such as cocaine, or in clinical situations that would increase the risk of a seizure such as abrupt alcohol or benzodiazepine withdrawal. As norepinephrine has been shown to have anticonvulsant properties, bupropion's inhibitory effects on NET are thought to contribute to its pro-convulsant activity. Bupropion has been shown to increase blood pressure and pose a risk for exacerbation of unmanaged or pre-existing hypertension, however, clinical trials of bupropion in smokers with CVD have not identified an increased incidence of CV events including stroke or heart attack. In clinical trials, the mean increase in systolic blood pressure associated with the use of bupropion was found to be 1.3 mmHg. •Pharmacodynamics (Drug B): Methoxsalen selectively inhibits the synthesis of deoxyribonucleic acid (DNA). The guanine and cytosine content correlates with the degree of Methoxsalen-induced cross-linking. At high concentrations of the drug, cellular RNA and protein synthesis are also suppressed. •Mechanism of action (Drug A): Bupropion is a norepinephrine/dopamine-reuptake inhibitor (NDRI) that exerts its pharmacological effects by weakly inhibiting the enzymes involved in the uptake of the neurotransmitters norepinephrine and dopamine from the synaptic cleft, therefore prolonging their duration of action within the neuronal synapse and the downstream effects of these neurotransmitters. More specifically, bupropion binds to the norepinephrine transporter (NET) and the dopamine transporter (DAT). Bupropion was originally classified as an "atypical" antidepressant because it does not exert the same effects as the classical antidepressants such as Monoamine Oxidase Inhibitors (MAOIs), Tricyclic Antidepressants (TCAs), or Selective Serotonin Reuptake Inhibitors (SSRIs). While it has comparable effectiveness to typical first-line options for the treatment of depression such as SSRIs, bupropion is a unique option for the treatment of MDD as it lacks any clinically relevant serotonergic effects, typical of other mood medications, or any effects on histamine or adrenaline receptors. Lack of activity at these receptors results in a more tolerable side effect profile; bupropion is less likely to cause sexual side effects, sedation, or weight gain as compared to SSRIs or TCAs, for example. When used as an aid to smoking cessation, bupropion is thought to confer its anti-craving and anti-withdrawal effects by inhibiting dopamine reuptake, which is thought to be involved in the reward pathways associated with nicotine, and through the antagonism of the nicotinic acetylcholinergic receptor (AChR), thereby blunting the effects of nicotine. Furthermore, the stimulatory effects produced by bupropion in the central nervous system are similar to nicotine's effects, making low doses of bupropion a suitable option as a nicotine substitute. When used in combination with naltrexone in the marketed product ContraveⓇ for chronic weight management, the two components are thought to have effects on areas of the brain involved in the regulation of food intake. This includes the hypothalamus, which is involved in appetite regulation, and the mesolimbic dopamine circuit, which is involved in reward pathways. Studies have shown that the combined activity of bupropion and naltrexone increase the firing rate of hypothalamic pro-opiomelanocortin (POMC) neurons and blockade of opioid receptor-mediated POMC auto-inhibition, which are associated with a reduction in food intake and increased energy expenditure. This combination was also found to reduce food intake when injected directly into the ventral tegmental area of the mesolimbic circuit in mice, which is an area associated with the regulation of reward pathways. •Mechanism of action (Drug B): After activation it binds preferentially to the guanine and cytosine moieties of DNA, leading to cross-linking of DNA, thus inhibiting DNA synthesis and function. •Absorption (Drug A): Bupropion is currently available in 3 distinct, but bioequivalent formulations: immediate release (IR), sustained-release (SR), and extended-release (XL). Immediate Release Formulation In humans, following oral administration of bupropion hydrochloride tablets, peak plasma bupropion concentrations are usually achieved within 2 hours. IR formulations provide a short duration of action and are therefore generally dosed three times per day. Sustained Release Formulation In humans, following oral administration of bupropion hydrochloride sustained-release tablets (SR), peak plasma concentration (Cmax) of bupropion is usually achieved within 3 hours. SR formulations provide a 12-hour extended release of medication and are therefore generally dosed twice per day. Extended Release Formulation Following single oral administration of bupropion hydrochloride extended-release tablets (XL) to healthy volunteers, the median time to peak plasma concentrations for bupropion was approximately 5 hours. The presence of food did not affect the peak concentration or area under the curve of bupropion. XL formulations provide a 24-hour extended release of medication and are therefore generally dosed once per day/ In a trial comparing chronic dosing with bupropion hydrochloride extended-release tablets (SR) 150 mg twice daily to bupropion immediate-release formulation 100 mg 3 times daily, the steady state Cmax for bupropion after bupropion hydrochloride sustained-release tablets (SR) administration was approximately 85% of those achieved after bupropion immediate-release formulation administration. Exposure (AUC) to bupropion was equivalent for both formulations. Bioequivalence was also demonstrated for all three major active metabolites (i.e., hydroxybupropion, threohydrobupropion and erythrohydrobupropion) for both Cmax and AUC. Thus, at steady state, bupropion hydrochloride sustained-release tablets (SR) given twice daily, and the immediate-release formulation of bupropion given 3 times daily, are essentially bioequivalent for both bupropion and the 3 quantitatively important metabolites. Furthermore, in a study comparing 14-day dosing with bupropion hydrochloride extended-release tablets (XL), 300 mg once-daily to the immediate-release formulation of bupropion at 100 mg 3 times daily, equivalence was demonstrated for peak plasma concentration and area under the curve for bupropion and the three metabolites (hydroxybupropion, threohydrobupropion, and erythrohydrobupropion). Additionally, in a study comparing 14-day dosing with bupropion hydrochloride extended-release tablets (XL) 300 mg once daily to the sustained-release formulation of bupropion at 150 mg 2 times daily, equivalence was demonstrated for peak plasma concentration and area under the curve for bupropion and the three metabolites. Bupropion hydrochloride extended-release tablets (SR) can be taken with or without food. Bupropion Cmax and AUC were increased by 11% to 35% and 16% to 19%, respectively, when bupropion hydrochloride extended-release tablets (SR) was administered with food to healthy volunteers in three trials. The food effect is not considered clinically significant. Following a single-dose administration of bupropion hydrochloride extended-release tablets (SR) in humans, Cmax of bupropion's metabolite hydroxybupropion occurs approximately 6 hours post-dose and is approximately 10 times the peak level of the parent drug at steady state. The elimination half-life of hydroxybupropion is approximately 20 (±5) hours and its AUC at steady state is about 17 times that of bupropion. The times to peak concentrations for the erythrohydrobupropion and threohydrobupropion metabolites are similar to that of the hydroxybupropion metabolite. However, their elimination half-lives are longer, 33(±10) and 37 (±13) hours, respectively, and steady-state AUCs are 1.5 and 7 times that of bupropion, respectively. •Absorption (Drug B): No absorption available •Volume of distribution (Drug A): No volume of distribution available •Volume of distribution (Drug B): No volume of distribution available •Protein binding (Drug A): In vitro tests show that bupropion is 84% bound to human plasma proteins at concentrations up to 200 mcg per mL. The extent of protein binding of the hydroxybupropion metabolite is similar to that for bupropion, whereas the extent of protein binding of the threohydrobupropion metabolite is about half that seen with bupropion. •Protein binding (Drug B): No protein binding available •Metabolism (Drug A): Bupropion is extensively metabolized in humans. Three metabolites are active: hydroxybupropion, which is formed via hydroxylation of the tert-butyl group of bupropion, and the amino-alcohol isomers, threohydrobupropion and erythrohydrobupropion, which are formed via reduction of the carbonyl group. In vitro findings suggest that CYP2B6 is the principal isoenzyme involved in the formation of hydroxybupropion, while cytochrome P450 enzymes are not involved in the formation of threohydrobupropion. Hydroxybupropion has been shown to have the same affinity as bupropion for the norepinephrine transporter (NET) but approximately 50% of its antidepressant activity despite reaching concentrations of ~10-fold higher than that of the parent drug. Oxidation of the bupropion side chain results in the formation of a glycine conjugate of meta-chlorobenzoic acid, which is then excreted as the major urinary metabolite. The potency and toxicity of the metabolites relative to bupropion have not been fully characterized. However, it has been demonstrated in an antidepressant screening test in mice that hydroxybupropion is one-half as potent as bupropion, while threohydrobupropion and erythrohydrobupropion are 5-fold less potent than bupropion. This may be of clinical importance because the plasma concentrations of the metabolites are as high as or higher than those of bupropion. Bupropion and its metabolites exhibit linear kinetics following chronic administration of 300 to 450 mg per day. •Metabolism (Drug B): No metabolism available •Route of elimination (Drug A): Bupropion is extensively metabolized in humans. Oxidation of the bupropion side chain results in the formation of a glycine conjugate of metachlorobenzoic acid, which is then excreted as the major urinary metabolite. Following oral administration of 200 mg of 14C-bupropion in humans, 87% and 10% of the radioactive dose were recovered in the urine and feces, respectively. However, the fraction of the oral dose of bupropion excreted unchanged was only 0.5%, a finding consistent with the extensive metabolism of bupropion. •Route of elimination (Drug B): In both mice and man, methoxsalen is rapidly metabolized. Approximately 95% of the drug is excreted as a series of metabolites in the urine within 24 hours (Pathak et al. 1977). •Half-life (Drug A): 24 hours •Half-life (Drug B): Approximately 2 hours •Clearance (Drug A): No clearance available •Clearance (Drug B): No clearance available •Toxicity (Drug A): Symptoms of overdose include seizures, hallucinations, loss of consciousness, tachycardia, and cardiac arrest. •Toxicity (Drug B): No toxicity available •Brand Names (Drug A): Aplenzin, Auvelity, Budeprion, Contrave, Forfivo, Wellbutrin, Zyban •Brand Names (Drug B): Oxsoralen, Uvadex •Synonyms (Drug A): No synonyms listed •Synonyms (Drug B): 8-Methoxyfuranocoumarin 8-methoxypsoralen 8-MOP 8-MP Ammoidin Methoxsalen Méthoxsalène Metoxaleno O-methylxanthotoxol Xanthotoxin Xanthotoxine •Summary (Drug A): Bupropion is a norepinephrine and dopamine reuptake inhibitor used in the treatment of major depressive disorder (MDD), seasonal affective disorder (SAD), and as an aid to smoking cessation. •Summary (Drug B): Methoxsalen is a furocoumarin used to treat psoriasis and vitiligo. Output: The renal excretion of drugs is the overall result of a combination of kidney processes that include glomerular filtration, passive diffusion, tubular secretion, and tubular reabsorption. Since two of these mechanisms - tubular secretion and reabsorption - are saturable processes , they are consequently susceptible to competition between multiple substrates excreted by the kidneys. If two or more medications that are mainly renally excreted are co-administered, they may compete for renal elimination; there is a large likelihood that one agent may "out-compete" or saturate the renal excretion mechanisms before the other concomitantly administered agent(s) are excreted. As a result, the elimination of these other concurrently administered agents may be inhibited or otherwise delayed, which could lead to increases in their serum concentrations and the risk, incidence, and/or severity of adverse effects associated with the exposure to such drugs. The severity of the interaction is minor.

Does Bupropion and Methoxyflurane interact?

•Drug A: Bupropion •Drug B: Methoxyflurane •Severity: MAJOR •Description: The metabolism of Methoxyflurane can be decreased when combined with Bupropion. •Extended Description: The subject drug is a strong CYP2D6 inhibitor and the affected drug is metabolized by CYP2D6. Concomitant administration may decrease the metabolism of the affected drug, which could increase serum concentrations as well as the risk and severity of adverse effects. •Indication (Drug A): Bupropion is indicated for the treatment of major depressive disorder (MDD), seasonal affective disorder (SAD), and as an aid to smoking cessation. When used in combination with naltrexone as the marketed product ContraveⓇ, bupropion is indicated as an adjunct to a reduced-calorie diet and increased physical activity for chronic weight management in adults with an initial body mass index (BMI) of: 30 kg/m^2 or greater (obese) or 27 kg/m^2 or greater (overweight) in the presence of at least one weight-related comorbid condition (e.g., hypertension, type 2 diabetes mellitus, or dyslipidemia). Bupropion is also used off-label as a first-line treatment in patients with ADHD and comorbid bipolar disorder when used as an adjunct to mood stabilizers. •Indication (Drug B): For use in the induction and maintenance of general anesthesia •Pharmacodynamics (Drug A): Bupropion is chemically unrelated to tricyclic, tetracyclic, selective serotonin re-uptake inhibitors, or other known antidepressant agents. Compared to classical tricyclic antidepressants, Bupropion is a relatively weak inhibitor of the neuronal uptake of norepinephrine and dopamine. In addition, Bupropion does not inhibit monoamine oxidase. Bupropion has been found to be essentially inactive at the serotonin transporter (SERT)(IC50 >10 000 nM), however both bupropion and its primary metabolite hydroxybupropion have been found to block the function of cation-selective serotonin type 3A receptors (5-HT3ARs). Bupropion produces dose-related central nervous system (CNS) stimulant effects in animals, as evidenced by increased locomotor activity, increased rates of responding in various schedule-controlled operant behaviour tasks, and, at high doses, induction of mild stereotyped behaviour. Due to these stimulant effects and selective activity at dopamine and norepinephrine receptors, bupropion has been identified as having an abuse potential. Bupropion has a similar structure to the controlled substance Cathinone, and has been identified as having mild amphetamine-like activity, particularly when inhaled or injected. Bupropion is also known to lower the seizure threshold, making any pre-existing seizure conditions a contraindication to its use. This risk is exacerbated when bupropion is combined with other drugs or substances that lower the seizure threshold, such as cocaine, or in clinical situations that would increase the risk of a seizure such as abrupt alcohol or benzodiazepine withdrawal. As norepinephrine has been shown to have anticonvulsant properties, bupropion's inhibitory effects on NET are thought to contribute to its pro-convulsant activity. Bupropion has been shown to increase blood pressure and pose a risk for exacerbation of unmanaged or pre-existing hypertension, however, clinical trials of bupropion in smokers with CVD have not identified an increased incidence of CV events including stroke or heart attack. In clinical trials, the mean increase in systolic blood pressure associated with the use of bupropion was found to be 1.3 mmHg. •Pharmacodynamics (Drug B): Methoxyflurane is a general inhalation anesthetic used for induction and maintenance of general anesthesia. It induces muscle relaxation and reduces pains sensitivity by altering tissue excitability. It does so by decreasing the extent of gap junction mediated cell-cell coupling and altering the activity of the channels that underlie the action potential. •Mechanism of action (Drug A): Bupropion is a norepinephrine/dopamine-reuptake inhibitor (NDRI) that exerts its pharmacological effects by weakly inhibiting the enzymes involved in the uptake of the neurotransmitters norepinephrine and dopamine from the synaptic cleft, therefore prolonging their duration of action within the neuronal synapse and the downstream effects of these neurotransmitters. More specifically, bupropion binds to the norepinephrine transporter (NET) and the dopamine transporter (DAT). Bupropion was originally classified as an "atypical" antidepressant because it does not exert the same effects as the classical antidepressants such as Monoamine Oxidase Inhibitors (MAOIs), Tricyclic Antidepressants (TCAs), or Selective Serotonin Reuptake Inhibitors (SSRIs). While it has comparable effectiveness to typical first-line options for the treatment of depression such as SSRIs, bupropion is a unique option for the treatment of MDD as it lacks any clinically relevant serotonergic effects, typical of other mood medications, or any effects on histamine or adrenaline receptors. Lack of activity at these receptors results in a more tolerable side effect profile; bupropion is less likely to cause sexual side effects, sedation, or weight gain as compared to SSRIs or TCAs, for example. When used as an aid to smoking cessation, bupropion is thought to confer its anti-craving and anti-withdrawal effects by inhibiting dopamine reuptake, which is thought to be involved in the reward pathways associated with nicotine, and through the antagonism of the nicotinic acetylcholinergic receptor (AChR), thereby blunting the effects of nicotine. Furthermore, the stimulatory effects produced by bupropion in the central nervous system are similar to nicotine's effects, making low doses of bupropion a suitable option as a nicotine substitute. When used in combination with naltrexone in the marketed product ContraveⓇ for chronic weight management, the two components are thought to have effects on areas of the brain involved in the regulation of food intake. This includes the hypothalamus, which is involved in appetite regulation, and the mesolimbic dopamine circuit, which is involved in reward pathways. Studies have shown that the combined activity of bupropion and naltrexone increase the firing rate of hypothalamic pro-opiomelanocortin (POMC) neurons and blockade of opioid receptor-mediated POMC auto-inhibition, which are associated with a reduction in food intake and increased energy expenditure. This combination was also found to reduce food intake when injected directly into the ventral tegmental area of the mesolimbic circuit in mice, which is an area associated with the regulation of reward pathways. •Mechanism of action (Drug B): Methoxyflurane induces a reduction in junctional conductance by decreasing gap junction channel opening times and increasing gap junction channel closing times. Methoxyflurane also activates calcium dependent ATPase in the sarcoplasmic reticulum by increasing the fluidity of the lipid membrane. It also appears to bind the D subunit of ATP synthase and NADH dehydogenase. Methoxyflurane also binds to the GABA receptor, the large conductance Ca activated potassium channel, the glutamate receptor and the glycine receptor. •Absorption (Drug A): Bupropion is currently available in 3 distinct, but bioequivalent formulations: immediate release (IR), sustained-release (SR), and extended-release (XL). Immediate Release Formulation In humans, following oral administration of bupropion hydrochloride tablets, peak plasma bupropion concentrations are usually achieved within 2 hours. IR formulations provide a short duration of action and are therefore generally dosed three times per day. Sustained Release Formulation In humans, following oral administration of bupropion hydrochloride sustained-release tablets (SR), peak plasma concentration (Cmax) of bupropion is usually achieved within 3 hours. SR formulations provide a 12-hour extended release of medication and are therefore generally dosed twice per day. Extended Release Formulation Following single oral administration of bupropion hydrochloride extended-release tablets (XL) to healthy volunteers, the median time to peak plasma concentrations for bupropion was approximately 5 hours. The presence of food did not affect the peak concentration or area under the curve of bupropion. XL formulations provide a 24-hour extended release of medication and are therefore generally dosed once per day/ In a trial comparing chronic dosing with bupropion hydrochloride extended-release tablets (SR) 150 mg twice daily to bupropion immediate-release formulation 100 mg 3 times daily, the steady state Cmax for bupropion after bupropion hydrochloride sustained-release tablets (SR) administration was approximately 85% of those achieved after bupropion immediate-release formulation administration. Exposure (AUC) to bupropion was equivalent for both formulations. Bioequivalence was also demonstrated for all three major active metabolites (i.e., hydroxybupropion, threohydrobupropion and erythrohydrobupropion) for both Cmax and AUC. Thus, at steady state, bupropion hydrochloride sustained-release tablets (SR) given twice daily, and the immediate-release formulation of bupropion given 3 times daily, are essentially bioequivalent for both bupropion and the 3 quantitatively important metabolites. Furthermore, in a study comparing 14-day dosing with bupropion hydrochloride extended-release tablets (XL), 300 mg once-daily to the immediate-release formulation of bupropion at 100 mg 3 times daily, equivalence was demonstrated for peak plasma concentration and area under the curve for bupropion and the three metabolites (hydroxybupropion, threohydrobupropion, and erythrohydrobupropion). Additionally, in a study comparing 14-day dosing with bupropion hydrochloride extended-release tablets (XL) 300 mg once daily to the sustained-release formulation of bupropion at 150 mg 2 times daily, equivalence was demonstrated for peak plasma concentration and area under the curve for bupropion and the three metabolites. Bupropion hydrochloride extended-release tablets (SR) can be taken with or without food. Bupropion Cmax and AUC were increased by 11% to 35% and 16% to 19%, respectively, when bupropion hydrochloride extended-release tablets (SR) was administered with food to healthy volunteers in three trials. The food effect is not considered clinically significant. Following a single-dose administration of bupropion hydrochloride extended-release tablets (SR) in humans, Cmax of bupropion's metabolite hydroxybupropion occurs approximately 6 hours post-dose and is approximately 10 times the peak level of the parent drug at steady state. The elimination half-life of hydroxybupropion is approximately 20 (±5) hours and its AUC at steady state is about 17 times that of bupropion. The times to peak concentrations for the erythrohydrobupropion and threohydrobupropion metabolites are similar to that of the hydroxybupropion metabolite. However, their elimination half-lives are longer, 33(±10) and 37 (±13) hours, respectively, and steady-state AUCs are 1.5 and 7 times that of bupropion, respectively. •Absorption (Drug B): No absorption available •Volume of distribution (Drug A): No volume of distribution available •Volume of distribution (Drug B): No volume of distribution available •Protein binding (Drug A): In vitro tests show that bupropion is 84% bound to human plasma proteins at concentrations up to 200 mcg per mL. The extent of protein binding of the hydroxybupropion metabolite is similar to that for bupropion, whereas the extent of protein binding of the threohydrobupropion metabolite is about half that seen with bupropion. •Protein binding (Drug B): No protein binding available •Metabolism (Drug A): Bupropion is extensively metabolized in humans. Three metabolites are active: hydroxybupropion, which is formed via hydroxylation of the tert-butyl group of bupropion, and the amino-alcohol isomers, threohydrobupropion and erythrohydrobupropion, which are formed via reduction of the carbonyl group. In vitro findings suggest that CYP2B6 is the principal isoenzyme involved in the formation of hydroxybupropion, while cytochrome P450 enzymes are not involved in the formation of threohydrobupropion. Hydroxybupropion has been shown to have the same affinity as bupropion for the norepinephrine transporter (NET) but approximately 50% of its antidepressant activity despite reaching concentrations of ~10-fold higher than that of the parent drug. Oxidation of the bupropion side chain results in the formation of a glycine conjugate of meta-chlorobenzoic acid, which is then excreted as the major urinary metabolite. The potency and toxicity of the metabolites relative to bupropion have not been fully characterized. However, it has been demonstrated in an antidepressant screening test in mice that hydroxybupropion is one-half as potent as bupropion, while threohydrobupropion and erythrohydrobupropion are 5-fold less potent than bupropion. This may be of clinical importance because the plasma concentrations of the metabolites are as high as or higher than those of bupropion. Bupropion and its metabolites exhibit linear kinetics following chronic administration of 300 to 450 mg per day. •Metabolism (Drug B): Hepatic. •Route of elimination (Drug A): Bupropion is extensively metabolized in humans. Oxidation of the bupropion side chain results in the formation of a glycine conjugate of metachlorobenzoic acid, which is then excreted as the major urinary metabolite. Following oral administration of 200 mg of 14C-bupropion in humans, 87% and 10% of the radioactive dose were recovered in the urine and feces, respectively. However, the fraction of the oral dose of bupropion excreted unchanged was only 0.5%, a finding consistent with the extensive metabolism of bupropion. •Route of elimination (Drug B): No route of elimination available •Half-life (Drug A): 24 hours •Half-life (Drug B): No half-life available •Clearance (Drug A): No clearance available •Clearance (Drug B): No clearance available •Toxicity (Drug A): Symptoms of overdose include seizures, hallucinations, loss of consciousness, tachycardia, and cardiac arrest. •Toxicity (Drug B): LD 50 =3600 mg/kg (Orally in rats). Symptoms of overexposure include eye irritation, CNS depression, analgesia, anesthesia, seizures, respiratory depression, and liver and kidney damage. •Brand Names (Drug A): Aplenzin, Auvelity, Budeprion, Contrave, Forfivo, Wellbutrin, Zyban •Brand Names (Drug B): No brand names available •Synonyms (Drug A): No synonyms listed •Synonyms (Drug B): Methoflurane Methoxyfluoran Methoxyfluran Methoxyflurane Methoxyfluranum Metoxiflurano •Summary (Drug A): Bupropion is a norepinephrine and dopamine reuptake inhibitor used in the treatment of major depressive disorder (MDD), seasonal affective disorder (SAD), and as an aid to smoking cessation. •Summary (Drug B): No summary available

The subject drug is a strong CYP2D6 inhibitor and the affected drug is metabolized by CYP2D6. Concomitant administration may decrease the metabolism of the affected drug, which could increase serum concentrations as well as the risk and severity of adverse effects. The severity of the interaction is major.

Question: Does Bupropion and Methoxyflurane interact? Information: •Drug A: Bupropion •Drug B: Methoxyflurane •Severity: MAJOR •Description: The metabolism of Methoxyflurane can be decreased when combined with Bupropion. •Extended Description: The subject drug is a strong CYP2D6 inhibitor and the affected drug is metabolized by CYP2D6. Concomitant administration may decrease the metabolism of the affected drug, which could increase serum concentrations as well as the risk and severity of adverse effects. •Indication (Drug A): Bupropion is indicated for the treatment of major depressive disorder (MDD), seasonal affective disorder (SAD), and as an aid to smoking cessation. When used in combination with naltrexone as the marketed product ContraveⓇ, bupropion is indicated as an adjunct to a reduced-calorie diet and increased physical activity for chronic weight management in adults with an initial body mass index (BMI) of: 30 kg/m^2 or greater (obese) or 27 kg/m^2 or greater (overweight) in the presence of at least one weight-related comorbid condition (e.g., hypertension, type 2 diabetes mellitus, or dyslipidemia). Bupropion is also used off-label as a first-line treatment in patients with ADHD and comorbid bipolar disorder when used as an adjunct to mood stabilizers. •Indication (Drug B): For use in the induction and maintenance of general anesthesia •Pharmacodynamics (Drug A): Bupropion is chemically unrelated to tricyclic, tetracyclic, selective serotonin re-uptake inhibitors, or other known antidepressant agents. Compared to classical tricyclic antidepressants, Bupropion is a relatively weak inhibitor of the neuronal uptake of norepinephrine and dopamine. In addition, Bupropion does not inhibit monoamine oxidase. Bupropion has been found to be essentially inactive at the serotonin transporter (SERT)(IC50 >10 000 nM), however both bupropion and its primary metabolite hydroxybupropion have been found to block the function of cation-selective serotonin type 3A receptors (5-HT3ARs). Bupropion produces dose-related central nervous system (CNS) stimulant effects in animals, as evidenced by increased locomotor activity, increased rates of responding in various schedule-controlled operant behaviour tasks, and, at high doses, induction of mild stereotyped behaviour. Due to these stimulant effects and selective activity at dopamine and norepinephrine receptors, bupropion has been identified as having an abuse potential. Bupropion has a similar structure to the controlled substance Cathinone, and has been identified as having mild amphetamine-like activity, particularly when inhaled or injected. Bupropion is also known to lower the seizure threshold, making any pre-existing seizure conditions a contraindication to its use. This risk is exacerbated when bupropion is combined with other drugs or substances that lower the seizure threshold, such as cocaine, or in clinical situations that would increase the risk of a seizure such as abrupt alcohol or benzodiazepine withdrawal. As norepinephrine has been shown to have anticonvulsant properties, bupropion's inhibitory effects on NET are thought to contribute to its pro-convulsant activity. Bupropion has been shown to increase blood pressure and pose a risk for exacerbation of unmanaged or pre-existing hypertension, however, clinical trials of bupropion in smokers with CVD have not identified an increased incidence of CV events including stroke or heart attack. In clinical trials, the mean increase in systolic blood pressure associated with the use of bupropion was found to be 1.3 mmHg. •Pharmacodynamics (Drug B): Methoxyflurane is a general inhalation anesthetic used for induction and maintenance of general anesthesia. It induces muscle relaxation and reduces pains sensitivity by altering tissue excitability. It does so by decreasing the extent of gap junction mediated cell-cell coupling and altering the activity of the channels that underlie the action potential. •Mechanism of action (Drug A): Bupropion is a norepinephrine/dopamine-reuptake inhibitor (NDRI) that exerts its pharmacological effects by weakly inhibiting the enzymes involved in the uptake of the neurotransmitters norepinephrine and dopamine from the synaptic cleft, therefore prolonging their duration of action within the neuronal synapse and the downstream effects of these neurotransmitters. More specifically, bupropion binds to the norepinephrine transporter (NET) and the dopamine transporter (DAT). Bupropion was originally classified as an "atypical" antidepressant because it does not exert the same effects as the classical antidepressants such as Monoamine Oxidase Inhibitors (MAOIs), Tricyclic Antidepressants (TCAs), or Selective Serotonin Reuptake Inhibitors (SSRIs). While it has comparable effectiveness to typical first-line options for the treatment of depression such as SSRIs, bupropion is a unique option for the treatment of MDD as it lacks any clinically relevant serotonergic effects, typical of other mood medications, or any effects on histamine or adrenaline receptors. Lack of activity at these receptors results in a more tolerable side effect profile; bupropion is less likely to cause sexual side effects, sedation, or weight gain as compared to SSRIs or TCAs, for example. When used as an aid to smoking cessation, bupropion is thought to confer its anti-craving and anti-withdrawal effects by inhibiting dopamine reuptake, which is thought to be involved in the reward pathways associated with nicotine, and through the antagonism of the nicotinic acetylcholinergic receptor (AChR), thereby blunting the effects of nicotine. Furthermore, the stimulatory effects produced by bupropion in the central nervous system are similar to nicotine's effects, making low doses of bupropion a suitable option as a nicotine substitute. When used in combination with naltrexone in the marketed product ContraveⓇ for chronic weight management, the two components are thought to have effects on areas of the brain involved in the regulation of food intake. This includes the hypothalamus, which is involved in appetite regulation, and the mesolimbic dopamine circuit, which is involved in reward pathways. Studies have shown that the combined activity of bupropion and naltrexone increase the firing rate of hypothalamic pro-opiomelanocortin (POMC) neurons and blockade of opioid receptor-mediated POMC auto-inhibition, which are associated with a reduction in food intake and increased energy expenditure. This combination was also found to reduce food intake when injected directly into the ventral tegmental area of the mesolimbic circuit in mice, which is an area associated with the regulation of reward pathways. •Mechanism of action (Drug B): Methoxyflurane induces a reduction in junctional conductance by decreasing gap junction channel opening times and increasing gap junction channel closing times. Methoxyflurane also activates calcium dependent ATPase in the sarcoplasmic reticulum by increasing the fluidity of the lipid membrane. It also appears to bind the D subunit of ATP synthase and NADH dehydogenase. Methoxyflurane also binds to the GABA receptor, the large conductance Ca activated potassium channel, the glutamate receptor and the glycine receptor. •Absorption (Drug A): Bupropion is currently available in 3 distinct, but bioequivalent formulations: immediate release (IR), sustained-release (SR), and extended-release (XL). Immediate Release Formulation In humans, following oral administration of bupropion hydrochloride tablets, peak plasma bupropion concentrations are usually achieved within 2 hours. IR formulations provide a short duration of action and are therefore generally dosed three times per day. Sustained Release Formulation In humans, following oral administration of bupropion hydrochloride sustained-release tablets (SR), peak plasma concentration (Cmax) of bupropion is usually achieved within 3 hours. SR formulations provide a 12-hour extended release of medication and are therefore generally dosed twice per day. Extended Release Formulation Following single oral administration of bupropion hydrochloride extended-release tablets (XL) to healthy volunteers, the median time to peak plasma concentrations for bupropion was approximately 5 hours. The presence of food did not affect the peak concentration or area under the curve of bupropion. XL formulations provide a 24-hour extended release of medication and are therefore generally dosed once per day/ In a trial comparing chronic dosing with bupropion hydrochloride extended-release tablets (SR) 150 mg twice daily to bupropion immediate-release formulation 100 mg 3 times daily, the steady state Cmax for bupropion after bupropion hydrochloride sustained-release tablets (SR) administration was approximately 85% of those achieved after bupropion immediate-release formulation administration. Exposure (AUC) to bupropion was equivalent for both formulations. Bioequivalence was also demonstrated for all three major active metabolites (i.e., hydroxybupropion, threohydrobupropion and erythrohydrobupropion) for both Cmax and AUC. Thus, at steady state, bupropion hydrochloride sustained-release tablets (SR) given twice daily, and the immediate-release formulation of bupropion given 3 times daily, are essentially bioequivalent for both bupropion and the 3 quantitatively important metabolites. Furthermore, in a study comparing 14-day dosing with bupropion hydrochloride extended-release tablets (XL), 300 mg once-daily to the immediate-release formulation of bupropion at 100 mg 3 times daily, equivalence was demonstrated for peak plasma concentration and area under the curve for bupropion and the three metabolites (hydroxybupropion, threohydrobupropion, and erythrohydrobupropion). Additionally, in a study comparing 14-day dosing with bupropion hydrochloride extended-release tablets (XL) 300 mg once daily to the sustained-release formulation of bupropion at 150 mg 2 times daily, equivalence was demonstrated for peak plasma concentration and area under the curve for bupropion and the three metabolites. Bupropion hydrochloride extended-release tablets (SR) can be taken with or without food. Bupropion Cmax and AUC were increased by 11% to 35% and 16% to 19%, respectively, when bupropion hydrochloride extended-release tablets (SR) was administered with food to healthy volunteers in three trials. The food effect is not considered clinically significant. Following a single-dose administration of bupropion hydrochloride extended-release tablets (SR) in humans, Cmax of bupropion's metabolite hydroxybupropion occurs approximately 6 hours post-dose and is approximately 10 times the peak level of the parent drug at steady state. The elimination half-life of hydroxybupropion is approximately 20 (±5) hours and its AUC at steady state is about 17 times that of bupropion. The times to peak concentrations for the erythrohydrobupropion and threohydrobupropion metabolites are similar to that of the hydroxybupropion metabolite. However, their elimination half-lives are longer, 33(±10) and 37 (±13) hours, respectively, and steady-state AUCs are 1.5 and 7 times that of bupropion, respectively. •Absorption (Drug B): No absorption available •Volume of distribution (Drug A): No volume of distribution available •Volume of distribution (Drug B): No volume of distribution available •Protein binding (Drug A): In vitro tests show that bupropion is 84% bound to human plasma proteins at concentrations up to 200 mcg per mL. The extent of protein binding of the hydroxybupropion metabolite is similar to that for bupropion, whereas the extent of protein binding of the threohydrobupropion metabolite is about half that seen with bupropion. •Protein binding (Drug B): No protein binding available •Metabolism (Drug A): Bupropion is extensively metabolized in humans. Three metabolites are active: hydroxybupropion, which is formed via hydroxylation of the tert-butyl group of bupropion, and the amino-alcohol isomers, threohydrobupropion and erythrohydrobupropion, which are formed via reduction of the carbonyl group. In vitro findings suggest that CYP2B6 is the principal isoenzyme involved in the formation of hydroxybupropion, while cytochrome P450 enzymes are not involved in the formation of threohydrobupropion. Hydroxybupropion has been shown to have the same affinity as bupropion for the norepinephrine transporter (NET) but approximately 50% of its antidepressant activity despite reaching concentrations of ~10-fold higher than that of the parent drug. Oxidation of the bupropion side chain results in the formation of a glycine conjugate of meta-chlorobenzoic acid, which is then excreted as the major urinary metabolite. The potency and toxicity of the metabolites relative to bupropion have not been fully characterized. However, it has been demonstrated in an antidepressant screening test in mice that hydroxybupropion is one-half as potent as bupropion, while threohydrobupropion and erythrohydrobupropion are 5-fold less potent than bupropion. This may be of clinical importance because the plasma concentrations of the metabolites are as high as or higher than those of bupropion. Bupropion and its metabolites exhibit linear kinetics following chronic administration of 300 to 450 mg per day. •Metabolism (Drug B): Hepatic. •Route of elimination (Drug A): Bupropion is extensively metabolized in humans. Oxidation of the bupropion side chain results in the formation of a glycine conjugate of metachlorobenzoic acid, which is then excreted as the major urinary metabolite. Following oral administration of 200 mg of 14C-bupropion in humans, 87% and 10% of the radioactive dose were recovered in the urine and feces, respectively. However, the fraction of the oral dose of bupropion excreted unchanged was only 0.5%, a finding consistent with the extensive metabolism of bupropion. •Route of elimination (Drug B): No route of elimination available •Half-life (Drug A): 24 hours •Half-life (Drug B): No half-life available •Clearance (Drug A): No clearance available •Clearance (Drug B): No clearance available •Toxicity (Drug A): Symptoms of overdose include seizures, hallucinations, loss of consciousness, tachycardia, and cardiac arrest. •Toxicity (Drug B): LD 50 =3600 mg/kg (Orally in rats). Symptoms of overexposure include eye irritation, CNS depression, analgesia, anesthesia, seizures, respiratory depression, and liver and kidney damage. •Brand Names (Drug A): Aplenzin, Auvelity, Budeprion, Contrave, Forfivo, Wellbutrin, Zyban •Brand Names (Drug B): No brand names available •Synonyms (Drug A): No synonyms listed •Synonyms (Drug B): Methoflurane Methoxyfluoran Methoxyfluran Methoxyflurane Methoxyfluranum Metoxiflurano •Summary (Drug A): Bupropion is a norepinephrine and dopamine reuptake inhibitor used in the treatment of major depressive disorder (MDD), seasonal affective disorder (SAD), and as an aid to smoking cessation. •Summary (Drug B): No summary available Output: The subject drug is a strong CYP2D6 inhibitor and the affected drug is metabolized by CYP2D6. Concomitant administration may decrease the metabolism of the affected drug, which could increase serum concentrations as well as the risk and severity of adverse effects. The severity of the interaction is major.

Does Bupropion and Methsuximide interact?

•Drug A: Bupropion •Drug B: Methsuximide •Severity: MODERATE •Description: The risk or severity of CNS depression can be increased when Bupropion is combined with Methsuximide. •Extended Description: Central nervous system (CNS) depressants can cause sedation, falls, respiratory depression, coma, and death.2,3 The potential interaction between a CNS depressant and another CNS depressant drug due to synergistic effects is well documented in the literature, although the risk and severity of CNS depression vary from each drug. The subject and affected drugs are both CNS depressants that, when co-administered, may result in a more profound CNS depression. As the risk and severity of CNS depression resulting from the combined use of CNS depressants vary from each agent, each interaction between CNS depressants should be considered individually. •Indication (Drug A): Bupropion is indicated for the treatment of major depressive disorder (MDD), seasonal affective disorder (SAD), and as an aid to smoking cessation. When used in combination with naltrexone as the marketed product ContraveⓇ, bupropion is indicated as an adjunct to a reduced-calorie diet and increased physical activity for chronic weight management in adults with an initial body mass index (BMI) of: 30 kg/m^2 or greater (obese) or 27 kg/m^2 or greater (overweight) in the presence of at least one weight-related comorbid condition (e.g., hypertension, type 2 diabetes mellitus, or dyslipidemia). Bupropion is also used off-label as a first-line treatment in patients with ADHD and comorbid bipolar disorder when used as an adjunct to mood stabilizers. •Indication (Drug B): For the control of absence (petit mal) seizures that are refractory to other drugs. •Pharmacodynamics (Drug A): Bupropion is chemically unrelated to tricyclic, tetracyclic, selective serotonin re-uptake inhibitors, or other known antidepressant agents. Compared to classical tricyclic antidepressants, Bupropion is a relatively weak inhibitor of the neuronal uptake of norepinephrine and dopamine. In addition, Bupropion does not inhibit monoamine oxidase. Bupropion has been found to be essentially inactive at the serotonin transporter (SERT)(IC50 >10 000 nM), however both bupropion and its primary metabolite hydroxybupropion have been found to block the function of cation-selective serotonin type 3A receptors (5-HT3ARs). Bupropion produces dose-related central nervous system (CNS) stimulant effects in animals, as evidenced by increased locomotor activity, increased rates of responding in various schedule-controlled operant behaviour tasks, and, at high doses, induction of mild stereotyped behaviour. Due to these stimulant effects and selective activity at dopamine and norepinephrine receptors, bupropion has been identified as having an abuse potential. Bupropion has a similar structure to the controlled substance Cathinone, and has been identified as having mild amphetamine-like activity, particularly when inhaled or injected. Bupropion is also known to lower the seizure threshold, making any pre-existing seizure conditions a contraindication to its use. This risk is exacerbated when bupropion is combined with other drugs or substances that lower the seizure threshold, such as cocaine, or in clinical situations that would increase the risk of a seizure such as abrupt alcohol or benzodiazepine withdrawal. As norepinephrine has been shown to have anticonvulsant properties, bupropion's inhibitory effects on NET are thought to contribute to its pro-convulsant activity. Bupropion has been shown to increase blood pressure and pose a risk for exacerbation of unmanaged or pre-existing hypertension, however, clinical trials of bupropion in smokers with CVD have not identified an increased incidence of CV events including stroke or heart attack. In clinical trials, the mean increase in systolic blood pressure associated with the use of bupropion was found to be 1.3 mmHg. •Pharmacodynamics (Drug B): Used in the treatment of epilepsy. Methsuximide suppresses the paroxysmal three cycle per second spike and wave activity associated with lapses of consciousness which is common in absence (petit mal) seizures. The frequency of epileptiform attacks is reduced, apparently by depression of the motor cortex and elevation of the threshold of the central nervous system to convulsive stimuli. •Mechanism of action (Drug A): Bupropion is a norepinephrine/dopamine-reuptake inhibitor (NDRI) that exerts its pharmacological effects by weakly inhibiting the enzymes involved in the uptake of the neurotransmitters norepinephrine and dopamine from the synaptic cleft, therefore prolonging their duration of action within the neuronal synapse and the downstream effects of these neurotransmitters. More specifically, bupropion binds to the norepinephrine transporter (NET) and the dopamine transporter (DAT). Bupropion was originally classified as an "atypical" antidepressant because it does not exert the same effects as the classical antidepressants such as Monoamine Oxidase Inhibitors (MAOIs), Tricyclic Antidepressants (TCAs), or Selective Serotonin Reuptake Inhibitors (SSRIs). While it has comparable effectiveness to typical first-line options for the treatment of depression such as SSRIs, bupropion is a unique option for the treatment of MDD as it lacks any clinically relevant serotonergic effects, typical of other mood medications, or any effects on histamine or adrenaline receptors. Lack of activity at these receptors results in a more tolerable side effect profile; bupropion is less likely to cause sexual side effects, sedation, or weight gain as compared to SSRIs or TCAs, for example. When used as an aid to smoking cessation, bupropion is thought to confer its anti-craving and anti-withdrawal effects by inhibiting dopamine reuptake, which is thought to be involved in the reward pathways associated with nicotine, and through the antagonism of the nicotinic acetylcholinergic receptor (AChR), thereby blunting the effects of nicotine. Furthermore, the stimulatory effects produced by bupropion in the central nervous system are similar to nicotine's effects, making low doses of bupropion a suitable option as a nicotine substitute. When used in combination with naltrexone in the marketed product ContraveⓇ for chronic weight management, the two components are thought to have effects on areas of the brain involved in the regulation of food intake. This includes the hypothalamus, which is involved in appetite regulation, and the mesolimbic dopamine circuit, which is involved in reward pathways. Studies have shown that the combined activity of bupropion and naltrexone increase the firing rate of hypothalamic pro-opiomelanocortin (POMC) neurons and blockade of opioid receptor-mediated POMC auto-inhibition, which are associated with a reduction in food intake and increased energy expenditure. This combination was also found to reduce food intake when injected directly into the ventral tegmental area of the mesolimbic circuit in mice, which is an area associated with the regulation of reward pathways. •Mechanism of action (Drug B): Binds to T-type voltage sensitive calcium channels. Voltage-sensitive calcium channels (VSCC) mediate the entry of calcium ions into excitable cells and are also involved in a variety of calcium-dependent processes, including muscle contraction, hormone or neurotransmitter release, gene expression, cell motility, cell division and cell death. The isoform alpha-1G gives rise to T-type calcium currents. T-type calcium channels belong to the "low-voltage activated (LVA)" group and are strongly blocked by mibefradil. A particularity of this type of channels is an opening at quite negative potentials and a voltage-dependent inactivation. T-type channels serve pacemaking functions in both central neurons and cardiac nodal cells and support calcium signaling in secretory cells and vascular smooth muscle. They may also be involved in the modulation of firing patterns of neurons which is important for information processing as well as in cell growth processes. •Absorption (Drug A): Bupropion is currently available in 3 distinct, but bioequivalent formulations: immediate release (IR), sustained-release (SR), and extended-release (XL). Immediate Release Formulation In humans, following oral administration of bupropion hydrochloride tablets, peak plasma bupropion concentrations are usually achieved within 2 hours. IR formulations provide a short duration of action and are therefore generally dosed three times per day. Sustained Release Formulation In humans, following oral administration of bupropion hydrochloride sustained-release tablets (SR), peak plasma concentration (Cmax) of bupropion is usually achieved within 3 hours. SR formulations provide a 12-hour extended release of medication and are therefore generally dosed twice per day. Extended Release Formulation Following single oral administration of bupropion hydrochloride extended-release tablets (XL) to healthy volunteers, the median time to peak plasma concentrations for bupropion was approximately 5 hours. The presence of food did not affect the peak concentration or area under the curve of bupropion. XL formulations provide a 24-hour extended release of medication and are therefore generally dosed once per day/ In a trial comparing chronic dosing with bupropion hydrochloride extended-release tablets (SR) 150 mg twice daily to bupropion immediate-release formulation 100 mg 3 times daily, the steady state Cmax for bupropion after bupropion hydrochloride sustained-release tablets (SR) administration was approximately 85% of those achieved after bupropion immediate-release formulation administration. Exposure (AUC) to bupropion was equivalent for both formulations. Bioequivalence was also demonstrated for all three major active metabolites (i.e., hydroxybupropion, threohydrobupropion and erythrohydrobupropion) for both Cmax and AUC. Thus, at steady state, bupropion hydrochloride sustained-release tablets (SR) given twice daily, and the immediate-release formulation of bupropion given 3 times daily, are essentially bioequivalent for both bupropion and the 3 quantitatively important metabolites. Furthermore, in a study comparing 14-day dosing with bupropion hydrochloride extended-release tablets (XL), 300 mg once-daily to the immediate-release formulation of bupropion at 100 mg 3 times daily, equivalence was demonstrated for peak plasma concentration and area under the curve for bupropion and the three metabolites (hydroxybupropion, threohydrobupropion, and erythrohydrobupropion). Additionally, in a study comparing 14-day dosing with bupropion hydrochloride extended-release tablets (XL) 300 mg once daily to the sustained-release formulation of bupropion at 150 mg 2 times daily, equivalence was demonstrated for peak plasma concentration and area under the curve for bupropion and the three metabolites. Bupropion hydrochloride extended-release tablets (SR) can be taken with or without food. Bupropion Cmax and AUC were increased by 11% to 35% and 16% to 19%, respectively, when bupropion hydrochloride extended-release tablets (SR) was administered with food to healthy volunteers in three trials. The food effect is not considered clinically significant. Following a single-dose administration of bupropion hydrochloride extended-release tablets (SR) in humans, Cmax of bupropion's metabolite hydroxybupropion occurs approximately 6 hours post-dose and is approximately 10 times the peak level of the parent drug at steady state. The elimination half-life of hydroxybupropion is approximately 20 (±5) hours and its AUC at steady state is about 17 times that of bupropion. The times to peak concentrations for the erythrohydrobupropion and threohydrobupropion metabolites are similar to that of the hydroxybupropion metabolite. However, their elimination half-lives are longer, 33(±10) and 37 (±13) hours, respectively, and steady-state AUCs are 1.5 and 7 times that of bupropion, respectively. •Absorption (Drug B): No absorption available •Volume of distribution (Drug A): No volume of distribution available •Volume of distribution (Drug B): No volume of distribution available •Protein binding (Drug A): In vitro tests show that bupropion is 84% bound to human plasma proteins at concentrations up to 200 mcg per mL. The extent of protein binding of the hydroxybupropion metabolite is similar to that for bupropion, whereas the extent of protein binding of the threohydrobupropion metabolite is about half that seen with bupropion. •Protein binding (Drug B): No protein binding available •Metabolism (Drug A): Bupropion is extensively metabolized in humans. Three metabolites are active: hydroxybupropion, which is formed via hydroxylation of the tert-butyl group of bupropion, and the amino-alcohol isomers, threohydrobupropion and erythrohydrobupropion, which are formed via reduction of the carbonyl group. In vitro findings suggest that CYP2B6 is the principal isoenzyme involved in the formation of hydroxybupropion, while cytochrome P450 enzymes are not involved in the formation of threohydrobupropion. Hydroxybupropion has been shown to have the same affinity as bupropion for the norepinephrine transporter (NET) but approximately 50% of its antidepressant activity despite reaching concentrations of ~10-fold higher than that of the parent drug. Oxidation of the bupropion side chain results in the formation of a glycine conjugate of meta-chlorobenzoic acid, which is then excreted as the major urinary metabolite. The potency and toxicity of the metabolites relative to bupropion have not been fully characterized. However, it has been demonstrated in an antidepressant screening test in mice that hydroxybupropion is one-half as potent as bupropion, while threohydrobupropion and erythrohydrobupropion are 5-fold less potent than bupropion. This may be of clinical importance because the plasma concentrations of the metabolites are as high as or higher than those of bupropion. Bupropion and its metabolites exhibit linear kinetics following chronic administration of 300 to 450 mg per day. •Metabolism (Drug B): No metabolism available •Route of elimination (Drug A): Bupropion is extensively metabolized in humans. Oxidation of the bupropion side chain results in the formation of a glycine conjugate of metachlorobenzoic acid, which is then excreted as the major urinary metabolite. Following oral administration of 200 mg of 14C-bupropion in humans, 87% and 10% of the radioactive dose were recovered in the urine and feces, respectively. However, the fraction of the oral dose of bupropion excreted unchanged was only 0.5%, a finding consistent with the extensive metabolism of bupropion. •Route of elimination (Drug B): No route of elimination available •Half-life (Drug A): 24 hours •Half-life (Drug B): 1.4-2.6 hours for mesuximide and 28-38 hours for the active metabolite. •Clearance (Drug A): No clearance available •Clearance (Drug B): No clearance available •Toxicity (Drug A): Symptoms of overdose include seizures, hallucinations, loss of consciousness, tachycardia, and cardiac arrest. •Toxicity (Drug B): Acute overdoses may produce nausea, vomiting, and CNS depression including coma with respiratory depression. Levels greater than 40 µg/mL have caused toxicity and coma has been seen at levels of 150 µg/mL. •Brand Names (Drug A): Aplenzin, Auvelity, Budeprion, Contrave, Forfivo, Wellbutrin, Zyban •Brand Names (Drug B): Celontin •Synonyms (Drug A): No synonyms listed •Synonyms (Drug B): alpha-Methylphensuximide Mesuximida Mesuximide Mesuximidum Methsuximid Methsuximide Metosuccimmide •Summary (Drug A): Bupropion is a norepinephrine and dopamine reuptake inhibitor used in the treatment of major depressive disorder (MDD), seasonal affective disorder (SAD), and as an aid to smoking cessation. •Summary (Drug B): Methsuximide is a succinimide anticonvulsant that increases the seizure threshold. Primarily used for childhood absence seizures. Functions by suppressing paroxysmal spike-and-wave patterns associated with lapses of consciousness in absence seizures.

Central nervous system (CNS) depressants can cause sedation, falls, respiratory depression, coma, and death.2,3 The potential interaction between a CNS depressant and another CNS depressant drug due to synergistic effects is well documented in the literature, although the risk and severity of CNS depression vary from each drug. The subject and affected drugs are both CNS depressants that, when co-administered, may result in a more profound CNS depression. As the risk and severity of CNS depression resulting from the combined use of CNS depressants vary from each agent, each interaction between CNS depressants should be considered individually. The severity of the interaction is moderate.

Question: Does Bupropion and Methsuximide interact? Information: •Drug A: Bupropion •Drug B: Methsuximide •Severity: MODERATE •Description: The risk or severity of CNS depression can be increased when Bupropion is combined with Methsuximide. •Extended Description: Central nervous system (CNS) depressants can cause sedation, falls, respiratory depression, coma, and death.2,3 The potential interaction between a CNS depressant and another CNS depressant drug due to synergistic effects is well documented in the literature, although the risk and severity of CNS depression vary from each drug. The subject and affected drugs are both CNS depressants that, when co-administered, may result in a more profound CNS depression. As the risk and severity of CNS depression resulting from the combined use of CNS depressants vary from each agent, each interaction between CNS depressants should be considered individually. •Indication (Drug A): Bupropion is indicated for the treatment of major depressive disorder (MDD), seasonal affective disorder (SAD), and as an aid to smoking cessation. When used in combination with naltrexone as the marketed product ContraveⓇ, bupropion is indicated as an adjunct to a reduced-calorie diet and increased physical activity for chronic weight management in adults with an initial body mass index (BMI) of: 30 kg/m^2 or greater (obese) or 27 kg/m^2 or greater (overweight) in the presence of at least one weight-related comorbid condition (e.g., hypertension, type 2 diabetes mellitus, or dyslipidemia). Bupropion is also used off-label as a first-line treatment in patients with ADHD and comorbid bipolar disorder when used as an adjunct to mood stabilizers. •Indication (Drug B): For the control of absence (petit mal) seizures that are refractory to other drugs. •Pharmacodynamics (Drug A): Bupropion is chemically unrelated to tricyclic, tetracyclic, selective serotonin re-uptake inhibitors, or other known antidepressant agents. Compared to classical tricyclic antidepressants, Bupropion is a relatively weak inhibitor of the neuronal uptake of norepinephrine and dopamine. In addition, Bupropion does not inhibit monoamine oxidase. Bupropion has been found to be essentially inactive at the serotonin transporter (SERT)(IC50 >10 000 nM), however both bupropion and its primary metabolite hydroxybupropion have been found to block the function of cation-selective serotonin type 3A receptors (5-HT3ARs). Bupropion produces dose-related central nervous system (CNS) stimulant effects in animals, as evidenced by increased locomotor activity, increased rates of responding in various schedule-controlled operant behaviour tasks, and, at high doses, induction of mild stereotyped behaviour. Due to these stimulant effects and selective activity at dopamine and norepinephrine receptors, bupropion has been identified as having an abuse potential. Bupropion has a similar structure to the controlled substance Cathinone, and has been identified as having mild amphetamine-like activity, particularly when inhaled or injected. Bupropion is also known to lower the seizure threshold, making any pre-existing seizure conditions a contraindication to its use. This risk is exacerbated when bupropion is combined with other drugs or substances that lower the seizure threshold, such as cocaine, or in clinical situations that would increase the risk of a seizure such as abrupt alcohol or benzodiazepine withdrawal. As norepinephrine has been shown to have anticonvulsant properties, bupropion's inhibitory effects on NET are thought to contribute to its pro-convulsant activity. Bupropion has been shown to increase blood pressure and pose a risk for exacerbation of unmanaged or pre-existing hypertension, however, clinical trials of bupropion in smokers with CVD have not identified an increased incidence of CV events including stroke or heart attack. In clinical trials, the mean increase in systolic blood pressure associated with the use of bupropion was found to be 1.3 mmHg. •Pharmacodynamics (Drug B): Used in the treatment of epilepsy. Methsuximide suppresses the paroxysmal three cycle per second spike and wave activity associated with lapses of consciousness which is common in absence (petit mal) seizures. The frequency of epileptiform attacks is reduced, apparently by depression of the motor cortex and elevation of the threshold of the central nervous system to convulsive stimuli. •Mechanism of action (Drug A): Bupropion is a norepinephrine/dopamine-reuptake inhibitor (NDRI) that exerts its pharmacological effects by weakly inhibiting the enzymes involved in the uptake of the neurotransmitters norepinephrine and dopamine from the synaptic cleft, therefore prolonging their duration of action within the neuronal synapse and the downstream effects of these neurotransmitters. More specifically, bupropion binds to the norepinephrine transporter (NET) and the dopamine transporter (DAT). Bupropion was originally classified as an "atypical" antidepressant because it does not exert the same effects as the classical antidepressants such as Monoamine Oxidase Inhibitors (MAOIs), Tricyclic Antidepressants (TCAs), or Selective Serotonin Reuptake Inhibitors (SSRIs). While it has comparable effectiveness to typical first-line options for the treatment of depression such as SSRIs, bupropion is a unique option for the treatment of MDD as it lacks any clinically relevant serotonergic effects, typical of other mood medications, or any effects on histamine or adrenaline receptors. Lack of activity at these receptors results in a more tolerable side effect profile; bupropion is less likely to cause sexual side effects, sedation, or weight gain as compared to SSRIs or TCAs, for example. When used as an aid to smoking cessation, bupropion is thought to confer its anti-craving and anti-withdrawal effects by inhibiting dopamine reuptake, which is thought to be involved in the reward pathways associated with nicotine, and through the antagonism of the nicotinic acetylcholinergic receptor (AChR), thereby blunting the effects of nicotine. Furthermore, the stimulatory effects produced by bupropion in the central nervous system are similar to nicotine's effects, making low doses of bupropion a suitable option as a nicotine substitute. When used in combination with naltrexone in the marketed product ContraveⓇ for chronic weight management, the two components are thought to have effects on areas of the brain involved in the regulation of food intake. This includes the hypothalamus, which is involved in appetite regulation, and the mesolimbic dopamine circuit, which is involved in reward pathways. Studies have shown that the combined activity of bupropion and naltrexone increase the firing rate of hypothalamic pro-opiomelanocortin (POMC) neurons and blockade of opioid receptor-mediated POMC auto-inhibition, which are associated with a reduction in food intake and increased energy expenditure. This combination was also found to reduce food intake when injected directly into the ventral tegmental area of the mesolimbic circuit in mice, which is an area associated with the regulation of reward pathways. •Mechanism of action (Drug B): Binds to T-type voltage sensitive calcium channels. Voltage-sensitive calcium channels (VSCC) mediate the entry of calcium ions into excitable cells and are also involved in a variety of calcium-dependent processes, including muscle contraction, hormone or neurotransmitter release, gene expression, cell motility, cell division and cell death. The isoform alpha-1G gives rise to T-type calcium currents. T-type calcium channels belong to the "low-voltage activated (LVA)" group and are strongly blocked by mibefradil. A particularity of this type of channels is an opening at quite negative potentials and a voltage-dependent inactivation. T-type channels serve pacemaking functions in both central neurons and cardiac nodal cells and support calcium signaling in secretory cells and vascular smooth muscle. They may also be involved in the modulation of firing patterns of neurons which is important for information processing as well as in cell growth processes. •Absorption (Drug A): Bupropion is currently available in 3 distinct, but bioequivalent formulations: immediate release (IR), sustained-release (SR), and extended-release (XL). Immediate Release Formulation In humans, following oral administration of bupropion hydrochloride tablets, peak plasma bupropion concentrations are usually achieved within 2 hours. IR formulations provide a short duration of action and are therefore generally dosed three times per day. Sustained Release Formulation In humans, following oral administration of bupropion hydrochloride sustained-release tablets (SR), peak plasma concentration (Cmax) of bupropion is usually achieved within 3 hours. SR formulations provide a 12-hour extended release of medication and are therefore generally dosed twice per day. Extended Release Formulation Following single oral administration of bupropion hydrochloride extended-release tablets (XL) to healthy volunteers, the median time to peak plasma concentrations for bupropion was approximately 5 hours. The presence of food did not affect the peak concentration or area under the curve of bupropion. XL formulations provide a 24-hour extended release of medication and are therefore generally dosed once per day/ In a trial comparing chronic dosing with bupropion hydrochloride extended-release tablets (SR) 150 mg twice daily to bupropion immediate-release formulation 100 mg 3 times daily, the steady state Cmax for bupropion after bupropion hydrochloride sustained-release tablets (SR) administration was approximately 85% of those achieved after bupropion immediate-release formulation administration. Exposure (AUC) to bupropion was equivalent for both formulations. Bioequivalence was also demonstrated for all three major active metabolites (i.e., hydroxybupropion, threohydrobupropion and erythrohydrobupropion) for both Cmax and AUC. Thus, at steady state, bupropion hydrochloride sustained-release tablets (SR) given twice daily, and the immediate-release formulation of bupropion given 3 times daily, are essentially bioequivalent for both bupropion and the 3 quantitatively important metabolites. Furthermore, in a study comparing 14-day dosing with bupropion hydrochloride extended-release tablets (XL), 300 mg once-daily to the immediate-release formulation of bupropion at 100 mg 3 times daily, equivalence was demonstrated for peak plasma concentration and area under the curve for bupropion and the three metabolites (hydroxybupropion, threohydrobupropion, and erythrohydrobupropion). Additionally, in a study comparing 14-day dosing with bupropion hydrochloride extended-release tablets (XL) 300 mg once daily to the sustained-release formulation of bupropion at 150 mg 2 times daily, equivalence was demonstrated for peak plasma concentration and area under the curve for bupropion and the three metabolites. Bupropion hydrochloride extended-release tablets (SR) can be taken with or without food. Bupropion Cmax and AUC were increased by 11% to 35% and 16% to 19%, respectively, when bupropion hydrochloride extended-release tablets (SR) was administered with food to healthy volunteers in three trials. The food effect is not considered clinically significant. Following a single-dose administration of bupropion hydrochloride extended-release tablets (SR) in humans, Cmax of bupropion's metabolite hydroxybupropion occurs approximately 6 hours post-dose and is approximately 10 times the peak level of the parent drug at steady state. The elimination half-life of hydroxybupropion is approximately 20 (±5) hours and its AUC at steady state is about 17 times that of bupropion. The times to peak concentrations for the erythrohydrobupropion and threohydrobupropion metabolites are similar to that of the hydroxybupropion metabolite. However, their elimination half-lives are longer, 33(±10) and 37 (±13) hours, respectively, and steady-state AUCs are 1.5 and 7 times that of bupropion, respectively. •Absorption (Drug B): No absorption available •Volume of distribution (Drug A): No volume of distribution available •Volume of distribution (Drug B): No volume of distribution available •Protein binding (Drug A): In vitro tests show that bupropion is 84% bound to human plasma proteins at concentrations up to 200 mcg per mL. The extent of protein binding of the hydroxybupropion metabolite is similar to that for bupropion, whereas the extent of protein binding of the threohydrobupropion metabolite is about half that seen with bupropion. •Protein binding (Drug B): No protein binding available •Metabolism (Drug A): Bupropion is extensively metabolized in humans. Three metabolites are active: hydroxybupropion, which is formed via hydroxylation of the tert-butyl group of bupropion, and the amino-alcohol isomers, threohydrobupropion and erythrohydrobupropion, which are formed via reduction of the carbonyl group. In vitro findings suggest that CYP2B6 is the principal isoenzyme involved in the formation of hydroxybupropion, while cytochrome P450 enzymes are not involved in the formation of threohydrobupropion. Hydroxybupropion has been shown to have the same affinity as bupropion for the norepinephrine transporter (NET) but approximately 50% of its antidepressant activity despite reaching concentrations of ~10-fold higher than that of the parent drug. Oxidation of the bupropion side chain results in the formation of a glycine conjugate of meta-chlorobenzoic acid, which is then excreted as the major urinary metabolite. The potency and toxicity of the metabolites relative to bupropion have not been fully characterized. However, it has been demonstrated in an antidepressant screening test in mice that hydroxybupropion is one-half as potent as bupropion, while threohydrobupropion and erythrohydrobupropion are 5-fold less potent than bupropion. This may be of clinical importance because the plasma concentrations of the metabolites are as high as or higher than those of bupropion. Bupropion and its metabolites exhibit linear kinetics following chronic administration of 300 to 450 mg per day. •Metabolism (Drug B): No metabolism available •Route of elimination (Drug A): Bupropion is extensively metabolized in humans. Oxidation of the bupropion side chain results in the formation of a glycine conjugate of metachlorobenzoic acid, which is then excreted as the major urinary metabolite. Following oral administration of 200 mg of 14C-bupropion in humans, 87% and 10% of the radioactive dose were recovered in the urine and feces, respectively. However, the fraction of the oral dose of bupropion excreted unchanged was only 0.5%, a finding consistent with the extensive metabolism of bupropion. •Route of elimination (Drug B): No route of elimination available •Half-life (Drug A): 24 hours •Half-life (Drug B): 1.4-2.6 hours for mesuximide and 28-38 hours for the active metabolite. •Clearance (Drug A): No clearance available •Clearance (Drug B): No clearance available •Toxicity (Drug A): Symptoms of overdose include seizures, hallucinations, loss of consciousness, tachycardia, and cardiac arrest. •Toxicity (Drug B): Acute overdoses may produce nausea, vomiting, and CNS depression including coma with respiratory depression. Levels greater than 40 µg/mL have caused toxicity and coma has been seen at levels of 150 µg/mL. •Brand Names (Drug A): Aplenzin, Auvelity, Budeprion, Contrave, Forfivo, Wellbutrin, Zyban •Brand Names (Drug B): Celontin •Synonyms (Drug A): No synonyms listed •Synonyms (Drug B): alpha-Methylphensuximide Mesuximida Mesuximide Mesuximidum Methsuximid Methsuximide Metosuccimmide •Summary (Drug A): Bupropion is a norepinephrine and dopamine reuptake inhibitor used in the treatment of major depressive disorder (MDD), seasonal affective disorder (SAD), and as an aid to smoking cessation. •Summary (Drug B): Methsuximide is a succinimide anticonvulsant that increases the seizure threshold. Primarily used for childhood absence seizures. Functions by suppressing paroxysmal spike-and-wave patterns associated with lapses of consciousness in absence seizures. Output: Central nervous system (CNS) depressants can cause sedation, falls, respiratory depression, coma, and death.2,3 The potential interaction between a CNS depressant and another CNS depressant drug due to synergistic effects is well documented in the literature, although the risk and severity of CNS depression vary from each drug. The subject and affected drugs are both CNS depressants that, when co-administered, may result in a more profound CNS depression. As the risk and severity of CNS depression resulting from the combined use of CNS depressants vary from each agent, each interaction between CNS depressants should be considered individually. The severity of the interaction is moderate.

Does Bupropion and Methyldopa interact?

•Drug A: Bupropion •Drug B: Methyldopa •Severity: MINOR •Description: Methyldopa may decrease the excretion rate of Bupropion which could result in a higher serum level. •Extended Description: The renal excretion of drugs is the overall result of a combination of kidney processes that include glomerular filtration, passive diffusion, tubular secretion, and tubular reabsorption. Since two of these mechanisms - tubular secretion and reabsorption - are saturable processes , they are consequently susceptible to competition between multiple substrates excreted by the kidneys. If two or more medications that are mainly renally excreted are co-administered, they may compete for renal elimination; there is a large likelihood that one agent may "out-compete" or saturate the renal excretion mechanisms before the other concomitantly administered agent(s) are excreted. As a result, the elimination of these other concurrently administered agents may be inhibited or otherwise delayed, which could lead to increases in their serum concentrations and the risk, incidence, and/or severity of adverse effects associated with the exposure to such drugs. •Indication (Drug A): Bupropion is indicated for the treatment of major depressive disorder (MDD), seasonal affective disorder (SAD), and as an aid to smoking cessation. When used in combination with naltrexone as the marketed product ContraveⓇ, bupropion is indicated as an adjunct to a reduced-calorie diet and increased physical activity for chronic weight management in adults with an initial body mass index (BMI) of: 30 kg/m^2 or greater (obese) or 27 kg/m^2 or greater (overweight) in the presence of at least one weight-related comorbid condition (e.g., hypertension, type 2 diabetes mellitus, or dyslipidemia). Bupropion is also used off-label as a first-line treatment in patients with ADHD and comorbid bipolar disorder when used as an adjunct to mood stabilizers. •Indication (Drug B): Methyldopa is indicated for the management of hypertension as monotherapy or in combination with hydrochlorothiazide. Methyldopa injection is used to manage hypertensive crises. •Pharmacodynamics (Drug A): Bupropion is chemically unrelated to tricyclic, tetracyclic, selective serotonin re-uptake inhibitors, or other known antidepressant agents. Compared to classical tricyclic antidepressants, Bupropion is a relatively weak inhibitor of the neuronal uptake of norepinephrine and dopamine. In addition, Bupropion does not inhibit monoamine oxidase. Bupropion has been found to be essentially inactive at the serotonin transporter (SERT)(IC50 >10 000 nM), however both bupropion and its primary metabolite hydroxybupropion have been found to block the function of cation-selective serotonin type 3A receptors (5-HT3ARs). Bupropion produces dose-related central nervous system (CNS) stimulant effects in animals, as evidenced by increased locomotor activity, increased rates of responding in various schedule-controlled operant behaviour tasks, and, at high doses, induction of mild stereotyped behaviour. Due to these stimulant effects and selective activity at dopamine and norepinephrine receptors, bupropion has been identified as having an abuse potential. Bupropion has a similar structure to the controlled substance Cathinone, and has been identified as having mild amphetamine-like activity, particularly when inhaled or injected. Bupropion is also known to lower the seizure threshold, making any pre-existing seizure conditions a contraindication to its use. This risk is exacerbated when bupropion is combined with other drugs or substances that lower the seizure threshold, such as cocaine, or in clinical situations that would increase the risk of a seizure such as abrupt alcohol or benzodiazepine withdrawal. As norepinephrine has been shown to have anticonvulsant properties, bupropion's inhibitory effects on NET are thought to contribute to its pro-convulsant activity. Bupropion has been shown to increase blood pressure and pose a risk for exacerbation of unmanaged or pre-existing hypertension, however, clinical trials of bupropion in smokers with CVD have not identified an increased incidence of CV events including stroke or heart attack. In clinical trials, the mean increase in systolic blood pressure associated with the use of bupropion was found to be 1.3 mmHg. •Pharmacodynamics (Drug B): Antihypertensive effects of methyldopa are mostly mediated by its pharmacologically active metabolite, alpha-methylnorepinephrine, which works as an agonist at central inhibitory alpha-adrenergic receptors. Stimulation of alpha-adrenergic receptors leads to decreased peripheral sympathetic tone and reduced arterial pressure. Methyldopa causes a net reduction in the tissue concentration of serotonin, dopamine, norepinephrine, and epinephrine. Overall, methyldopa lowers both standing blood pressure and especially supine blood pressure, with infrequent symptomatic postural hypotension. Methyldopa also reduces plasma renin activity but has negligible effects on glomerular filtration rate, renal blood flow, or filtration fraction. It also has no direct effect on cardiac function but in some patients, a slowed heart rate may occur. Following oral administration, blood-pressure-lowering effects are observed within 12 to 24 hours in most patients, and a maximum reduction in blood pressure occurs in 4 to 6 hours. Blood pressure returns to pre-treatment levels within 24 to 48 hours following drug discontinuation. Following intravenous administration, the blood-pressure-lowering effects of methyldopa last for about 10 to 16 hours. •Mechanism of action (Drug A): Bupropion is a norepinephrine/dopamine-reuptake inhibitor (NDRI) that exerts its pharmacological effects by weakly inhibiting the enzymes involved in the uptake of the neurotransmitters norepinephrine and dopamine from the synaptic cleft, therefore prolonging their duration of action within the neuronal synapse and the downstream effects of these neurotransmitters. More specifically, bupropion binds to the norepinephrine transporter (NET) and the dopamine transporter (DAT). Bupropion was originally classified as an "atypical" antidepressant because it does not exert the same effects as the classical antidepressants such as Monoamine Oxidase Inhibitors (MAOIs), Tricyclic Antidepressants (TCAs), or Selective Serotonin Reuptake Inhibitors (SSRIs). While it has comparable effectiveness to typical first-line options for the treatment of depression such as SSRIs, bupropion is a unique option for the treatment of MDD as it lacks any clinically relevant serotonergic effects, typical of other mood medications, or any effects on histamine or adrenaline receptors. Lack of activity at these receptors results in a more tolerable side effect profile; bupropion is less likely to cause sexual side effects, sedation, or weight gain as compared to SSRIs or TCAs, for example. When used as an aid to smoking cessation, bupropion is thought to confer its anti-craving and anti-withdrawal effects by inhibiting dopamine reuptake, which is thought to be involved in the reward pathways associated with nicotine, and through the antagonism of the nicotinic acetylcholinergic receptor (AChR), thereby blunting the effects of nicotine. Furthermore, the stimulatory effects produced by bupropion in the central nervous system are similar to nicotine's effects, making low doses of bupropion a suitable option as a nicotine substitute. When used in combination with naltrexone in the marketed product ContraveⓇ for chronic weight management, the two components are thought to have effects on areas of the brain involved in the regulation of food intake. This includes the hypothalamus, which is involved in appetite regulation, and the mesolimbic dopamine circuit, which is involved in reward pathways. Studies have shown that the combined activity of bupropion and naltrexone increase the firing rate of hypothalamic pro-opiomelanocortin (POMC) neurons and blockade of opioid receptor-mediated POMC auto-inhibition, which are associated with a reduction in food intake and increased energy expenditure. This combination was also found to reduce food intake when injected directly into the ventral tegmental area of the mesolimbic circuit in mice, which is an area associated with the regulation of reward pathways. •Mechanism of action (Drug B): The exact mechanism of methyldopa is not fully elucidated; however, the main mechanisms of methyldopa involve its actions on alpha-adrenergic receptor and the aromatic L-amino acid decarboxylase enzyme, to a lesser extent. The sympathetic outflow is regulated by alpha (α)-2 adrenergic receptors and imidazoline receptors expressed on adrenergic neurons within the rostral ventrolateral medulla. Methyldopa is metabolized to α‐methylnorepinephrine via dopamine beta-hydroxylase activity and, consequently, alpha-methylepinephrine via phenylethanolamine-N-methyltransferase activity. Mediating the therapeutic effects of methyldopa, α‐methylnorepinephrine and α-methylepinephrine active metabolites are agonists at presynaptic alpha-2 adrenergic receptors in the brainstem. Stimulating alpha-2 adrenergic receptors results in the inhibition of adrenergic neuronal outflow and attenuation of norepinephrine release in the brainstem. Consequently, the output of vasoconstrictor adrenergic signals to the peripheral sympathetic nervous system is reduced, leading to a reduction in blood pressure. The L-isomer of alpha-methyldopa also reduces blood pressure by inhibiting aromatic L-amino acid decarboxylase, also known as DOPA decarboxylase, which is an enzyme responsible for the syntheses of dopamine and serotonin. Inhibiting this enzyme leads to depletion of biogenic amines such as norepinephrine. However, inhibition of aromatic L-amino acid decarboxylase plays a minimal role in the blood-pressure‐lowering effect of methyldopa. •Absorption (Drug A): Bupropion is currently available in 3 distinct, but bioequivalent formulations: immediate release (IR), sustained-release (SR), and extended-release (XL). Immediate Release Formulation In humans, following oral administration of bupropion hydrochloride tablets, peak plasma bupropion concentrations are usually achieved within 2 hours. IR formulations provide a short duration of action and are therefore generally dosed three times per day. Sustained Release Formulation In humans, following oral administration of bupropion hydrochloride sustained-release tablets (SR), peak plasma concentration (Cmax) of bupropion is usually achieved within 3 hours. SR formulations provide a 12-hour extended release of medication and are therefore generally dosed twice per day. Extended Release Formulation Following single oral administration of bupropion hydrochloride extended-release tablets (XL) to healthy volunteers, the median time to peak plasma concentrations for bupropion was approximately 5 hours. The presence of food did not affect the peak concentration or area under the curve of bupropion. XL formulations provide a 24-hour extended release of medication and are therefore generally dosed once per day/ In a trial comparing chronic dosing with bupropion hydrochloride extended-release tablets (SR) 150 mg twice daily to bupropion immediate-release formulation 100 mg 3 times daily, the steady state Cmax for bupropion after bupropion hydrochloride sustained-release tablets (SR) administration was approximately 85% of those achieved after bupropion immediate-release formulation administration. Exposure (AUC) to bupropion was equivalent for both formulations. Bioequivalence was also demonstrated for all three major active metabolites (i.e., hydroxybupropion, threohydrobupropion and erythrohydrobupropion) for both Cmax and AUC. Thus, at steady state, bupropion hydrochloride sustained-release tablets (SR) given twice daily, and the immediate-release formulation of bupropion given 3 times daily, are essentially bioequivalent for both bupropion and the 3 quantitatively important metabolites. Furthermore, in a study comparing 14-day dosing with bupropion hydrochloride extended-release tablets (XL), 300 mg once-daily to the immediate-release formulation of bupropion at 100 mg 3 times daily, equivalence was demonstrated for peak plasma concentration and area under the curve for bupropion and the three metabolites (hydroxybupropion, threohydrobupropion, and erythrohydrobupropion). Additionally, in a study comparing 14-day dosing with bupropion hydrochloride extended-release tablets (XL) 300 mg once daily to the sustained-release formulation of bupropion at 150 mg 2 times daily, equivalence was demonstrated for peak plasma concentration and area under the curve for bupropion and the three metabolites. Bupropion hydrochloride extended-release tablets (SR) can be taken with or without food. Bupropion Cmax and AUC were increased by 11% to 35% and 16% to 19%, respectively, when bupropion hydrochloride extended-release tablets (SR) was administered with food to healthy volunteers in three trials. The food effect is not considered clinically significant. Following a single-dose administration of bupropion hydrochloride extended-release tablets (SR) in humans, Cmax of bupropion's metabolite hydroxybupropion occurs approximately 6 hours post-dose and is approximately 10 times the peak level of the parent drug at steady state. The elimination half-life of hydroxybupropion is approximately 20 (±5) hours and its AUC at steady state is about 17 times that of bupropion. The times to peak concentrations for the erythrohydrobupropion and threohydrobupropion metabolites are similar to that of the hydroxybupropion metabolite. However, their elimination half-lives are longer, 33(±10) and 37 (±13) hours, respectively, and steady-state AUCs are 1.5 and 7 times that of bupropion, respectively. •Absorption (Drug B): Methyldopa is incompletely absorbed from the gastrointestinal tract following oral administration. In healthy individuals, the inactive D-isomer is less readily absorbed than the active L-isomer. The mean bioavailability of methyldopa is 25%, ranging from eight to 62%. Following oral administration, about 50% of the dose is absorbed and T max is about three to six hours. •Volume of distribution (Drug A): No volume of distribution available •Volume of distribution (Drug B): The apparent volume of distribution ranges between 0.19 and 0.32L/kg and the total volume of distribution ranges from 0.41 to 0.72L/kg. Since methyldopa is lipid-soluble, it crosses the placental barrier, appears in cord blood, and appears in breast milk. •Protein binding (Drug A): In vitro tests show that bupropion is 84% bound to human plasma proteins at concentrations up to 200 mcg per mL. The extent of protein binding of the hydroxybupropion metabolite is similar to that for bupropion, whereas the extent of protein binding of the threohydrobupropion metabolite is about half that seen with bupropion. •Protein binding (Drug B): Methyldopa is less than 15% bound to plasma proteins and its primary metabolite, O-sulfate metabolite, is about 50% protein bound. Following intravenous administration, approximately 17% of the dose in normal subjects were circulating in the plasma as free methyldopa. •Metabolism (Drug A): Bupropion is extensively metabolized in humans. Three metabolites are active: hydroxybupropion, which is formed via hydroxylation of the tert-butyl group of bupropion, and the amino-alcohol isomers, threohydrobupropion and erythrohydrobupropion, which are formed via reduction of the carbonyl group. In vitro findings suggest that CYP2B6 is the principal isoenzyme involved in the formation of hydroxybupropion, while cytochrome P450 enzymes are not involved in the formation of threohydrobupropion. Hydroxybupropion has been shown to have the same affinity as bupropion for the norepinephrine transporter (NET) but approximately 50% of its antidepressant activity despite reaching concentrations of ~10-fold higher than that of the parent drug. Oxidation of the bupropion side chain results in the formation of a glycine conjugate of meta-chlorobenzoic acid, which is then excreted as the major urinary metabolite. The potency and toxicity of the metabolites relative to bupropion have not been fully characterized. However, it has been demonstrated in an antidepressant screening test in mice that hydroxybupropion is one-half as potent as bupropion, while threohydrobupropion and erythrohydrobupropion are 5-fold less potent than bupropion. This may be of clinical importance because the plasma concentrations of the metabolites are as high as or higher than those of bupropion. Bupropion and its metabolites exhibit linear kinetics following chronic administration of 300 to 450 mg per day. •Metabolism (Drug B): Two isomers of methyldopa undergo different metabolic pathways. L-α-methyldopa is biotransformed to its pharmacologically active metabolite, alpha-methylnorepinephrine. Methyldopa is extensively metabolized in the liver to form the main circulating metabolite in the plasma, alpha (α)-methyldopa mono-O-sulfate. Its other metabolites also include 3-O-methyl-α-methyldopa; 3,4-dihydroxyphenylacetone; α-methyldopamine; and 3-O-methyl-α-methyldopamine. These metabolites are further conjugated in the liver to form sulfate conjugates. After intravenous administration, the most prominent metabolites are alpha-methyldopamine and the glucuronide of dihydroxyphenylacetone, along with other uncharacterized metabolites. D-α-methyldopa, which is the inactive isomer of methyldopa, is also metabolized to 3-O-methyl-α-methyldopa and 3,4-dihydroxyphenylacetone to a minimal extent; however, there are no amines (α-methyldopamine and 3-O-methyl-α-methyldopamine) formed. •Route of elimination (Drug A): Bupropion is extensively metabolized in humans. Oxidation of the bupropion side chain results in the formation of a glycine conjugate of metachlorobenzoic acid, which is then excreted as the major urinary metabolite. Following oral administration of 200 mg of 14C-bupropion in humans, 87% and 10% of the radioactive dose were recovered in the urine and feces, respectively. However, the fraction of the oral dose of bupropion excreted unchanged was only 0.5%, a finding consistent with the extensive metabolism of bupropion. •Route of elimination (Drug B): Approximately 70% of absorbed methyldopa is excreted in the urine as unchanged parent drug (24%) and α-methyldopa mono-O-sulfate (64%), with variability.3-O-methyl-α-methyldopa accounted for about 4% of urinary excretion products. Other metabolites like 3,4-dihydroxyphenylacetone, α-methyldopamine, and 3-O-methyl-α-methyldopamine are also excreted in urine. Unabsorbed drug is excreted in feces as the unchanged parent compound. After oral doses, excretion is essentially complete in 36 hours. Due to attenuated excretion in patients with renal failure, accumulation of the drug and its metabolites may occur, possibly leading to more profound and prolonged hypotensive effects in these patients. •Half-life (Drug A): 24 hours •Half-life (Drug B): The plasma half-life of methyldopa is 105 minutes. Following intravenous injection, the plasma half-life of methyldopa ranges from 90 to 127 minutes. •Clearance (Drug A): No clearance available •Clearance (Drug B): The renal clearance is about 130 mL/min in normal subjects and is decreased in patients with renal insufficiency. •Toxicity (Drug A): Symptoms of overdose include seizures, hallucinations, loss of consciousness, tachycardia, and cardiac arrest. •Toxicity (Drug B): The lowest published toxic dose via oral route is 44 gm/kg/3Y (intermittent) in a female. Oral LD 50 is 5000 mg/kg in rats and 5300 mg/kg in mice. Intraperitoneal LD 50 is 300 mg/kg in rats and 150 mg/kg in mice. Acute overdosage is characterized by acute hypotension and other presentations attributed to the brain and gastrointestinal dysfunction, such as excessive sedation, weakness, bradycardia, dizziness, light-headedness, constipation, distention, flatus, diarrhea, nausea, and vomiting. Symptomatic and supportive measures should be initiated in the event of methyldopa overdose. Overdosage following recent oral ingestion can be managed by gastric lavage or emesis, as well as infusions to limit further drug absorption. Cardiac rate and output, blood volume, electrolyte balance, paralytic ileus, urinary function and cerebral activity should be closely monitored. The use of sympathomimetic drugs such as levarterenol, epinephrine, and metaraminol bitartrate, or dialysis may be considered. •Brand Names (Drug A): Aplenzin, Auvelity, Budeprion, Contrave, Forfivo, Wellbutrin, Zyban •Brand Names (Drug B): No brand names available •Synonyms (Drug A): No synonyms listed •Synonyms (Drug B): Alpha medopa alpha-Methyl dopa Alphamethyldopa L-alpha-Methyldopa L-Methyl Dopa Methyl dopa Methyldopa metildopa •Summary (Drug A): Bupropion is a norepinephrine and dopamine reuptake inhibitor used in the treatment of major depressive disorder (MDD), seasonal affective disorder (SAD), and as an aid to smoking cessation. •Summary (Drug B): Methyldopa is a centrally-acting alpha-2 adrenergic agonist used to manage hypertension alone or in combination with hydrochlorothiazide, and to treat hypertensive crises.

The renal excretion of drugs is the overall result of a combination of kidney processes that include glomerular filtration, passive diffusion, tubular secretion, and tubular reabsorption. Since two of these mechanisms - tubular secretion and reabsorption - are saturable processes , they are consequently susceptible to competition between multiple substrates excreted by the kidneys. If two or more medications that are mainly renally excreted are co-administered, they may compete for renal elimination; there is a large likelihood that one agent may "out-compete" or saturate the renal excretion mechanisms before the other concomitantly administered agent(s) are excreted. As a result, the elimination of these other concurrently administered agents may be inhibited or otherwise delayed, which could lead to increases in their serum concentrations and the risk, incidence, and/or severity of adverse effects associated with the exposure to such drugs. The severity of the interaction is minor.

Question: Does Bupropion and Methyldopa interact? Information: •Drug A: Bupropion •Drug B: Methyldopa •Severity: MINOR •Description: Methyldopa may decrease the excretion rate of Bupropion which could result in a higher serum level. •Extended Description: The renal excretion of drugs is the overall result of a combination of kidney processes that include glomerular filtration, passive diffusion, tubular secretion, and tubular reabsorption. Since two of these mechanisms - tubular secretion and reabsorption - are saturable processes , they are consequently susceptible to competition between multiple substrates excreted by the kidneys. If two or more medications that are mainly renally excreted are co-administered, they may compete for renal elimination; there is a large likelihood that one agent may "out-compete" or saturate the renal excretion mechanisms before the other concomitantly administered agent(s) are excreted. As a result, the elimination of these other concurrently administered agents may be inhibited or otherwise delayed, which could lead to increases in their serum concentrations and the risk, incidence, and/or severity of adverse effects associated with the exposure to such drugs. •Indication (Drug A): Bupropion is indicated for the treatment of major depressive disorder (MDD), seasonal affective disorder (SAD), and as an aid to smoking cessation. When used in combination with naltrexone as the marketed product ContraveⓇ, bupropion is indicated as an adjunct to a reduced-calorie diet and increased physical activity for chronic weight management in adults with an initial body mass index (BMI) of: 30 kg/m^2 or greater (obese) or 27 kg/m^2 or greater (overweight) in the presence of at least one weight-related comorbid condition (e.g., hypertension, type 2 diabetes mellitus, or dyslipidemia). Bupropion is also used off-label as a first-line treatment in patients with ADHD and comorbid bipolar disorder when used as an adjunct to mood stabilizers. •Indication (Drug B): Methyldopa is indicated for the management of hypertension as monotherapy or in combination with hydrochlorothiazide. Methyldopa injection is used to manage hypertensive crises. •Pharmacodynamics (Drug A): Bupropion is chemically unrelated to tricyclic, tetracyclic, selective serotonin re-uptake inhibitors, or other known antidepressant agents. Compared to classical tricyclic antidepressants, Bupropion is a relatively weak inhibitor of the neuronal uptake of norepinephrine and dopamine. In addition, Bupropion does not inhibit monoamine oxidase. Bupropion has been found to be essentially inactive at the serotonin transporter (SERT)(IC50 >10 000 nM), however both bupropion and its primary metabolite hydroxybupropion have been found to block the function of cation-selective serotonin type 3A receptors (5-HT3ARs). Bupropion produces dose-related central nervous system (CNS) stimulant effects in animals, as evidenced by increased locomotor activity, increased rates of responding in various schedule-controlled operant behaviour tasks, and, at high doses, induction of mild stereotyped behaviour. Due to these stimulant effects and selective activity at dopamine and norepinephrine receptors, bupropion has been identified as having an abuse potential. Bupropion has a similar structure to the controlled substance Cathinone, and has been identified as having mild amphetamine-like activity, particularly when inhaled or injected. Bupropion is also known to lower the seizure threshold, making any pre-existing seizure conditions a contraindication to its use. This risk is exacerbated when bupropion is combined with other drugs or substances that lower the seizure threshold, such as cocaine, or in clinical situations that would increase the risk of a seizure such as abrupt alcohol or benzodiazepine withdrawal. As norepinephrine has been shown to have anticonvulsant properties, bupropion's inhibitory effects on NET are thought to contribute to its pro-convulsant activity. Bupropion has been shown to increase blood pressure and pose a risk for exacerbation of unmanaged or pre-existing hypertension, however, clinical trials of bupropion in smokers with CVD have not identified an increased incidence of CV events including stroke or heart attack. In clinical trials, the mean increase in systolic blood pressure associated with the use of bupropion was found to be 1.3 mmHg. •Pharmacodynamics (Drug B): Antihypertensive effects of methyldopa are mostly mediated by its pharmacologically active metabolite, alpha-methylnorepinephrine, which works as an agonist at central inhibitory alpha-adrenergic receptors. Stimulation of alpha-adrenergic receptors leads to decreased peripheral sympathetic tone and reduced arterial pressure. Methyldopa causes a net reduction in the tissue concentration of serotonin, dopamine, norepinephrine, and epinephrine. Overall, methyldopa lowers both standing blood pressure and especially supine blood pressure, with infrequent symptomatic postural hypotension. Methyldopa also reduces plasma renin activity but has negligible effects on glomerular filtration rate, renal blood flow, or filtration fraction. It also has no direct effect on cardiac function but in some patients, a slowed heart rate may occur. Following oral administration, blood-pressure-lowering effects are observed within 12 to 24 hours in most patients, and a maximum reduction in blood pressure occurs in 4 to 6 hours. Blood pressure returns to pre-treatment levels within 24 to 48 hours following drug discontinuation. Following intravenous administration, the blood-pressure-lowering effects of methyldopa last for about 10 to 16 hours. •Mechanism of action (Drug A): Bupropion is a norepinephrine/dopamine-reuptake inhibitor (NDRI) that exerts its pharmacological effects by weakly inhibiting the enzymes involved in the uptake of the neurotransmitters norepinephrine and dopamine from the synaptic cleft, therefore prolonging their duration of action within the neuronal synapse and the downstream effects of these neurotransmitters. More specifically, bupropion binds to the norepinephrine transporter (NET) and the dopamine transporter (DAT). Bupropion was originally classified as an "atypical" antidepressant because it does not exert the same effects as the classical antidepressants such as Monoamine Oxidase Inhibitors (MAOIs), Tricyclic Antidepressants (TCAs), or Selective Serotonin Reuptake Inhibitors (SSRIs). While it has comparable effectiveness to typical first-line options for the treatment of depression such as SSRIs, bupropion is a unique option for the treatment of MDD as it lacks any clinically relevant serotonergic effects, typical of other mood medications, or any effects on histamine or adrenaline receptors. Lack of activity at these receptors results in a more tolerable side effect profile; bupropion is less likely to cause sexual side effects, sedation, or weight gain as compared to SSRIs or TCAs, for example. When used as an aid to smoking cessation, bupropion is thought to confer its anti-craving and anti-withdrawal effects by inhibiting dopamine reuptake, which is thought to be involved in the reward pathways associated with nicotine, and through the antagonism of the nicotinic acetylcholinergic receptor (AChR), thereby blunting the effects of nicotine. Furthermore, the stimulatory effects produced by bupropion in the central nervous system are similar to nicotine's effects, making low doses of bupropion a suitable option as a nicotine substitute. When used in combination with naltrexone in the marketed product ContraveⓇ for chronic weight management, the two components are thought to have effects on areas of the brain involved in the regulation of food intake. This includes the hypothalamus, which is involved in appetite regulation, and the mesolimbic dopamine circuit, which is involved in reward pathways. Studies have shown that the combined activity of bupropion and naltrexone increase the firing rate of hypothalamic pro-opiomelanocortin (POMC) neurons and blockade of opioid receptor-mediated POMC auto-inhibition, which are associated with a reduction in food intake and increased energy expenditure. This combination was also found to reduce food intake when injected directly into the ventral tegmental area of the mesolimbic circuit in mice, which is an area associated with the regulation of reward pathways. •Mechanism of action (Drug B): The exact mechanism of methyldopa is not fully elucidated; however, the main mechanisms of methyldopa involve its actions on alpha-adrenergic receptor and the aromatic L-amino acid decarboxylase enzyme, to a lesser extent. The sympathetic outflow is regulated by alpha (α)-2 adrenergic receptors and imidazoline receptors expressed on adrenergic neurons within the rostral ventrolateral medulla. Methyldopa is metabolized to α‐methylnorepinephrine via dopamine beta-hydroxylase activity and, consequently, alpha-methylepinephrine via phenylethanolamine-N-methyltransferase activity. Mediating the therapeutic effects of methyldopa, α‐methylnorepinephrine and α-methylepinephrine active metabolites are agonists at presynaptic alpha-2 adrenergic receptors in the brainstem. Stimulating alpha-2 adrenergic receptors results in the inhibition of adrenergic neuronal outflow and attenuation of norepinephrine release in the brainstem. Consequently, the output of vasoconstrictor adrenergic signals to the peripheral sympathetic nervous system is reduced, leading to a reduction in blood pressure. The L-isomer of alpha-methyldopa also reduces blood pressure by inhibiting aromatic L-amino acid decarboxylase, also known as DOPA decarboxylase, which is an enzyme responsible for the syntheses of dopamine and serotonin. Inhibiting this enzyme leads to depletion of biogenic amines such as norepinephrine. However, inhibition of aromatic L-amino acid decarboxylase plays a minimal role in the blood-pressure‐lowering effect of methyldopa. •Absorption (Drug A): Bupropion is currently available in 3 distinct, but bioequivalent formulations: immediate release (IR), sustained-release (SR), and extended-release (XL). Immediate Release Formulation In humans, following oral administration of bupropion hydrochloride tablets, peak plasma bupropion concentrations are usually achieved within 2 hours. IR formulations provide a short duration of action and are therefore generally dosed three times per day. Sustained Release Formulation In humans, following oral administration of bupropion hydrochloride sustained-release tablets (SR), peak plasma concentration (Cmax) of bupropion is usually achieved within 3 hours. SR formulations provide a 12-hour extended release of medication and are therefore generally dosed twice per day. Extended Release Formulation Following single oral administration of bupropion hydrochloride extended-release tablets (XL) to healthy volunteers, the median time to peak plasma concentrations for bupropion was approximately 5 hours. The presence of food did not affect the peak concentration or area under the curve of bupropion. XL formulations provide a 24-hour extended release of medication and are therefore generally dosed once per day/ In a trial comparing chronic dosing with bupropion hydrochloride extended-release tablets (SR) 150 mg twice daily to bupropion immediate-release formulation 100 mg 3 times daily, the steady state Cmax for bupropion after bupropion hydrochloride sustained-release tablets (SR) administration was approximately 85% of those achieved after bupropion immediate-release formulation administration. Exposure (AUC) to bupropion was equivalent for both formulations. Bioequivalence was also demonstrated for all three major active metabolites (i.e., hydroxybupropion, threohydrobupropion and erythrohydrobupropion) for both Cmax and AUC. Thus, at steady state, bupropion hydrochloride sustained-release tablets (SR) given twice daily, and the immediate-release formulation of bupropion given 3 times daily, are essentially bioequivalent for both bupropion and the 3 quantitatively important metabolites. Furthermore, in a study comparing 14-day dosing with bupropion hydrochloride extended-release tablets (XL), 300 mg once-daily to the immediate-release formulation of bupropion at 100 mg 3 times daily, equivalence was demonstrated for peak plasma concentration and area under the curve for bupropion and the three metabolites (hydroxybupropion, threohydrobupropion, and erythrohydrobupropion). Additionally, in a study comparing 14-day dosing with bupropion hydrochloride extended-release tablets (XL) 300 mg once daily to the sustained-release formulation of bupropion at 150 mg 2 times daily, equivalence was demonstrated for peak plasma concentration and area under the curve for bupropion and the three metabolites. Bupropion hydrochloride extended-release tablets (SR) can be taken with or without food. Bupropion Cmax and AUC were increased by 11% to 35% and 16% to 19%, respectively, when bupropion hydrochloride extended-release tablets (SR) was administered with food to healthy volunteers in three trials. The food effect is not considered clinically significant. Following a single-dose administration of bupropion hydrochloride extended-release tablets (SR) in humans, Cmax of bupropion's metabolite hydroxybupropion occurs approximately 6 hours post-dose and is approximately 10 times the peak level of the parent drug at steady state. The elimination half-life of hydroxybupropion is approximately 20 (±5) hours and its AUC at steady state is about 17 times that of bupropion. The times to peak concentrations for the erythrohydrobupropion and threohydrobupropion metabolites are similar to that of the hydroxybupropion metabolite. However, their elimination half-lives are longer, 33(±10) and 37 (±13) hours, respectively, and steady-state AUCs are 1.5 and 7 times that of bupropion, respectively. •Absorption (Drug B): Methyldopa is incompletely absorbed from the gastrointestinal tract following oral administration. In healthy individuals, the inactive D-isomer is less readily absorbed than the active L-isomer. The mean bioavailability of methyldopa is 25%, ranging from eight to 62%. Following oral administration, about 50% of the dose is absorbed and T max is about three to six hours. •Volume of distribution (Drug A): No volume of distribution available •Volume of distribution (Drug B): The apparent volume of distribution ranges between 0.19 and 0.32L/kg and the total volume of distribution ranges from 0.41 to 0.72L/kg. Since methyldopa is lipid-soluble, it crosses the placental barrier, appears in cord blood, and appears in breast milk. •Protein binding (Drug A): In vitro tests show that bupropion is 84% bound to human plasma proteins at concentrations up to 200 mcg per mL. The extent of protein binding of the hydroxybupropion metabolite is similar to that for bupropion, whereas the extent of protein binding of the threohydrobupropion metabolite is about half that seen with bupropion. •Protein binding (Drug B): Methyldopa is less than 15% bound to plasma proteins and its primary metabolite, O-sulfate metabolite, is about 50% protein bound. Following intravenous administration, approximately 17% of the dose in normal subjects were circulating in the plasma as free methyldopa. •Metabolism (Drug A): Bupropion is extensively metabolized in humans. Three metabolites are active: hydroxybupropion, which is formed via hydroxylation of the tert-butyl group of bupropion, and the amino-alcohol isomers, threohydrobupropion and erythrohydrobupropion, which are formed via reduction of the carbonyl group. In vitro findings suggest that CYP2B6 is the principal isoenzyme involved in the formation of hydroxybupropion, while cytochrome P450 enzymes are not involved in the formation of threohydrobupropion. Hydroxybupropion has been shown to have the same affinity as bupropion for the norepinephrine transporter (NET) but approximately 50% of its antidepressant activity despite reaching concentrations of ~10-fold higher than that of the parent drug. Oxidation of the bupropion side chain results in the formation of a glycine conjugate of meta-chlorobenzoic acid, which is then excreted as the major urinary metabolite. The potency and toxicity of the metabolites relative to bupropion have not been fully characterized. However, it has been demonstrated in an antidepressant screening test in mice that hydroxybupropion is one-half as potent as bupropion, while threohydrobupropion and erythrohydrobupropion are 5-fold less potent than bupropion. This may be of clinical importance because the plasma concentrations of the metabolites are as high as or higher than those of bupropion. Bupropion and its metabolites exhibit linear kinetics following chronic administration of 300 to 450 mg per day. •Metabolism (Drug B): Two isomers of methyldopa undergo different metabolic pathways. L-α-methyldopa is biotransformed to its pharmacologically active metabolite, alpha-methylnorepinephrine. Methyldopa is extensively metabolized in the liver to form the main circulating metabolite in the plasma, alpha (α)-methyldopa mono-O-sulfate. Its other metabolites also include 3-O-methyl-α-methyldopa; 3,4-dihydroxyphenylacetone; α-methyldopamine; and 3-O-methyl-α-methyldopamine. These metabolites are further conjugated in the liver to form sulfate conjugates. After intravenous administration, the most prominent metabolites are alpha-methyldopamine and the glucuronide of dihydroxyphenylacetone, along with other uncharacterized metabolites. D-α-methyldopa, which is the inactive isomer of methyldopa, is also metabolized to 3-O-methyl-α-methyldopa and 3,4-dihydroxyphenylacetone to a minimal extent; however, there are no amines (α-methyldopamine and 3-O-methyl-α-methyldopamine) formed. •Route of elimination (Drug A): Bupropion is extensively metabolized in humans. Oxidation of the bupropion side chain results in the formation of a glycine conjugate of metachlorobenzoic acid, which is then excreted as the major urinary metabolite. Following oral administration of 200 mg of 14C-bupropion in humans, 87% and 10% of the radioactive dose were recovered in the urine and feces, respectively. However, the fraction of the oral dose of bupropion excreted unchanged was only 0.5%, a finding consistent with the extensive metabolism of bupropion. •Route of elimination (Drug B): Approximately 70% of absorbed methyldopa is excreted in the urine as unchanged parent drug (24%) and α-methyldopa mono-O-sulfate (64%), with variability.3-O-methyl-α-methyldopa accounted for about 4% of urinary excretion products. Other metabolites like 3,4-dihydroxyphenylacetone, α-methyldopamine, and 3-O-methyl-α-methyldopamine are also excreted in urine. Unabsorbed drug is excreted in feces as the unchanged parent compound. After oral doses, excretion is essentially complete in 36 hours. Due to attenuated excretion in patients with renal failure, accumulation of the drug and its metabolites may occur, possibly leading to more profound and prolonged hypotensive effects in these patients. •Half-life (Drug A): 24 hours •Half-life (Drug B): The plasma half-life of methyldopa is 105 minutes. Following intravenous injection, the plasma half-life of methyldopa ranges from 90 to 127 minutes. •Clearance (Drug A): No clearance available •Clearance (Drug B): The renal clearance is about 130 mL/min in normal subjects and is decreased in patients with renal insufficiency. •Toxicity (Drug A): Symptoms of overdose include seizures, hallucinations, loss of consciousness, tachycardia, and cardiac arrest. •Toxicity (Drug B): The lowest published toxic dose via oral route is 44 gm/kg/3Y (intermittent) in a female. Oral LD 50 is 5000 mg/kg in rats and 5300 mg/kg in mice. Intraperitoneal LD 50 is 300 mg/kg in rats and 150 mg/kg in mice. Acute overdosage is characterized by acute hypotension and other presentations attributed to the brain and gastrointestinal dysfunction, such as excessive sedation, weakness, bradycardia, dizziness, light-headedness, constipation, distention, flatus, diarrhea, nausea, and vomiting. Symptomatic and supportive measures should be initiated in the event of methyldopa overdose. Overdosage following recent oral ingestion can be managed by gastric lavage or emesis, as well as infusions to limit further drug absorption. Cardiac rate and output, blood volume, electrolyte balance, paralytic ileus, urinary function and cerebral activity should be closely monitored. The use of sympathomimetic drugs such as levarterenol, epinephrine, and metaraminol bitartrate, or dialysis may be considered. •Brand Names (Drug A): Aplenzin, Auvelity, Budeprion, Contrave, Forfivo, Wellbutrin, Zyban •Brand Names (Drug B): No brand names available •Synonyms (Drug A): No synonyms listed •Synonyms (Drug B): Alpha medopa alpha-Methyl dopa Alphamethyldopa L-alpha-Methyldopa L-Methyl Dopa Methyl dopa Methyldopa metildopa •Summary (Drug A): Bupropion is a norepinephrine and dopamine reuptake inhibitor used in the treatment of major depressive disorder (MDD), seasonal affective disorder (SAD), and as an aid to smoking cessation. •Summary (Drug B): Methyldopa is a centrally-acting alpha-2 adrenergic agonist used to manage hypertension alone or in combination with hydrochlorothiazide, and to treat hypertensive crises. Output: The renal excretion of drugs is the overall result of a combination of kidney processes that include glomerular filtration, passive diffusion, tubular secretion, and tubular reabsorption. Since two of these mechanisms - tubular secretion and reabsorption - are saturable processes , they are consequently susceptible to competition between multiple substrates excreted by the kidneys. If two or more medications that are mainly renally excreted are co-administered, they may compete for renal elimination; there is a large likelihood that one agent may "out-compete" or saturate the renal excretion mechanisms before the other concomitantly administered agent(s) are excreted. As a result, the elimination of these other concurrently administered agents may be inhibited or otherwise delayed, which could lead to increases in their serum concentrations and the risk, incidence, and/or severity of adverse effects associated with the exposure to such drugs. The severity of the interaction is minor.

Does Bupropion and Methylene blue interact?

•Drug A: Bupropion •Drug B: Methylene blue •Severity: MAJOR •Description: The risk or severity of adverse effects can be increased when Methylene blue is combined with Bupropion. •Extended Description: Bupropion is a dopaminergic agent that is used in the treatment of Parkinson's disease, depression, and smoking cessation. Based on the findings from animal studies, co-administration of bupropion with monoamine oxidase inhibitors may enhance the acute toxicity effects of bupropion, as indicated by an increase in mortality and a decrease in time to death . This interaction applies to both immediate release and sustained release forms of bupropion. •Indication (Drug A): Bupropion is indicated for the treatment of major depressive disorder (MDD), seasonal affective disorder (SAD), and as an aid to smoking cessation. When used in combination with naltrexone as the marketed product ContraveⓇ, bupropion is indicated as an adjunct to a reduced-calorie diet and increased physical activity for chronic weight management in adults with an initial body mass index (BMI) of: 30 kg/m^2 or greater (obese) or 27 kg/m^2 or greater (overweight) in the presence of at least one weight-related comorbid condition (e.g., hypertension, type 2 diabetes mellitus, or dyslipidemia). Bupropion is also used off-label as a first-line treatment in patients with ADHD and comorbid bipolar disorder when used as an adjunct to mood stabilizers. •Indication (Drug B): Indicated for the treatment of pediatric and adult patients with acquired methemoglobinemia. Other clinical applications of methylene blue include improvement of hypotension associated with various clinical states, an antiseptic in urinary tract infections, treatment of hypoxia and hyperdynamic circulation in cirrhosis of liver and severe hepatopulmonary syndrome, and treatment of ifofosamide induced neurotoxicity. •Pharmacodynamics (Drug A): Bupropion is chemically unrelated to tricyclic, tetracyclic, selective serotonin re-uptake inhibitors, or other known antidepressant agents. Compared to classical tricyclic antidepressants, Bupropion is a relatively weak inhibitor of the neuronal uptake of norepinephrine and dopamine. In addition, Bupropion does not inhibit monoamine oxidase. Bupropion has been found to be essentially inactive at the serotonin transporter (SERT)(IC50 >10 000 nM), however both bupropion and its primary metabolite hydroxybupropion have been found to block the function of cation-selective serotonin type 3A receptors (5-HT3ARs). Bupropion produces dose-related central nervous system (CNS) stimulant effects in animals, as evidenced by increased locomotor activity, increased rates of responding in various schedule-controlled operant behaviour tasks, and, at high doses, induction of mild stereotyped behaviour. Due to these stimulant effects and selective activity at dopamine and norepinephrine receptors, bupropion has been identified as having an abuse potential. Bupropion has a similar structure to the controlled substance Cathinone, and has been identified as having mild amphetamine-like activity, particularly when inhaled or injected. Bupropion is also known to lower the seizure threshold, making any pre-existing seizure conditions a contraindication to its use. This risk is exacerbated when bupropion is combined with other drugs or substances that lower the seizure threshold, such as cocaine, or in clinical situations that would increase the risk of a seizure such as abrupt alcohol or benzodiazepine withdrawal. As norepinephrine has been shown to have anticonvulsant properties, bupropion's inhibitory effects on NET are thought to contribute to its pro-convulsant activity. Bupropion has been shown to increase blood pressure and pose a risk for exacerbation of unmanaged or pre-existing hypertension, however, clinical trials of bupropion in smokers with CVD have not identified an increased incidence of CV events including stroke or heart attack. In clinical trials, the mean increase in systolic blood pressure associated with the use of bupropion was found to be 1.3 mmHg. •Pharmacodynamics (Drug B): No pharmacodynamics available •Mechanism of action (Drug A): Bupropion is a norepinephrine/dopamine-reuptake inhibitor (NDRI) that exerts its pharmacological effects by weakly inhibiting the enzymes involved in the uptake of the neurotransmitters norepinephrine and dopamine from the synaptic cleft, therefore prolonging their duration of action within the neuronal synapse and the downstream effects of these neurotransmitters. More specifically, bupropion binds to the norepinephrine transporter (NET) and the dopamine transporter (DAT). Bupropion was originally classified as an "atypical" antidepressant because it does not exert the same effects as the classical antidepressants such as Monoamine Oxidase Inhibitors (MAOIs), Tricyclic Antidepressants (TCAs), or Selective Serotonin Reuptake Inhibitors (SSRIs). While it has comparable effectiveness to typical first-line options for the treatment of depression such as SSRIs, bupropion is a unique option for the treatment of MDD as it lacks any clinically relevant serotonergic effects, typical of other mood medications, or any effects on histamine or adrenaline receptors. Lack of activity at these receptors results in a more tolerable side effect profile; bupropion is less likely to cause sexual side effects, sedation, or weight gain as compared to SSRIs or TCAs, for example. When used as an aid to smoking cessation, bupropion is thought to confer its anti-craving and anti-withdrawal effects by inhibiting dopamine reuptake, which is thought to be involved in the reward pathways associated with nicotine, and through the antagonism of the nicotinic acetylcholinergic receptor (AChR), thereby blunting the effects of nicotine. Furthermore, the stimulatory effects produced by bupropion in the central nervous system are similar to nicotine's effects, making low doses of bupropion a suitable option as a nicotine substitute. When used in combination with naltrexone in the marketed product ContraveⓇ for chronic weight management, the two components are thought to have effects on areas of the brain involved in the regulation of food intake. This includes the hypothalamus, which is involved in appetite regulation, and the mesolimbic dopamine circuit, which is involved in reward pathways. Studies have shown that the combined activity of bupropion and naltrexone increase the firing rate of hypothalamic pro-opiomelanocortin (POMC) neurons and blockade of opioid receptor-mediated POMC auto-inhibition, which are associated with a reduction in food intake and increased energy expenditure. This combination was also found to reduce food intake when injected directly into the ventral tegmental area of the mesolimbic circuit in mice, which is an area associated with the regulation of reward pathways. •Mechanism of action (Drug B): Main mechanism of action involves inhibition of nitric oxide synthase and guanylate cyclase. In Alzheimers Disease: a mechanistic study found that methylene blue oxidizes cysteine sulfhydryl groups on tau to keep tau monomeric. One preclinical treatment study in tauopathy mice reported anti-inflammatory or neuroprotective effects mediated by the Nrf2/antioxidant response element (ARE); another reported insoluble tau reduction and a learning and memory benefit when given early. In Methemoglobinemia: Methylene Blue acts by reacting within RBC to form leukomethylene blue, which is a reducing agent of oxidized hemoglobin converting the ferric ion (fe+++) back to its oxygen-carrying ferrous state(fe++). As antimalarial agent: Methylene Blue, a specific inhibitor of P.falciparum glutathione reductase has the potential to reverse CQ resistance and it prevents the polymerization of haem into haemozoin similar to 4-amino-quinoline antimalarials. For ifosfamide induced neurotoxicity: Methylene blue functions as an alternate electron acceptor. It acts to reverse the NADH inhibition caused by gluconeogenesis in the liver while blocking the transformation of chloroethylamine into chloroacetaldehyde. In addition, it inhibits various amine oxidase activities, which also prevents the formation of chloroacetaldehyde. •Absorption (Drug A): Bupropion is currently available in 3 distinct, but bioequivalent formulations: immediate release (IR), sustained-release (SR), and extended-release (XL). Immediate Release Formulation In humans, following oral administration of bupropion hydrochloride tablets, peak plasma bupropion concentrations are usually achieved within 2 hours. IR formulations provide a short duration of action and are therefore generally dosed three times per day. Sustained Release Formulation In humans, following oral administration of bupropion hydrochloride sustained-release tablets (SR), peak plasma concentration (Cmax) of bupropion is usually achieved within 3 hours. SR formulations provide a 12-hour extended release of medication and are therefore generally dosed twice per day. Extended Release Formulation Following single oral administration of bupropion hydrochloride extended-release tablets (XL) to healthy volunteers, the median time to peak plasma concentrations for bupropion was approximately 5 hours. The presence of food did not affect the peak concentration or area under the curve of bupropion. XL formulations provide a 24-hour extended release of medication and are therefore generally dosed once per day/ In a trial comparing chronic dosing with bupropion hydrochloride extended-release tablets (SR) 150 mg twice daily to bupropion immediate-release formulation 100 mg 3 times daily, the steady state Cmax for bupropion after bupropion hydrochloride sustained-release tablets (SR) administration was approximately 85% of those achieved after bupropion immediate-release formulation administration. Exposure (AUC) to bupropion was equivalent for both formulations. Bioequivalence was also demonstrated for all three major active metabolites (i.e., hydroxybupropion, threohydrobupropion and erythrohydrobupropion) for both Cmax and AUC. Thus, at steady state, bupropion hydrochloride sustained-release tablets (SR) given twice daily, and the immediate-release formulation of bupropion given 3 times daily, are essentially bioequivalent for both bupropion and the 3 quantitatively important metabolites. Furthermore, in a study comparing 14-day dosing with bupropion hydrochloride extended-release tablets (XL), 300 mg once-daily to the immediate-release formulation of bupropion at 100 mg 3 times daily, equivalence was demonstrated for peak plasma concentration and area under the curve for bupropion and the three metabolites (hydroxybupropion, threohydrobupropion, and erythrohydrobupropion). Additionally, in a study comparing 14-day dosing with bupropion hydrochloride extended-release tablets (XL) 300 mg once daily to the sustained-release formulation of bupropion at 150 mg 2 times daily, equivalence was demonstrated for peak plasma concentration and area under the curve for bupropion and the three metabolites. Bupropion hydrochloride extended-release tablets (SR) can be taken with or without food. Bupropion Cmax and AUC were increased by 11% to 35% and 16% to 19%, respectively, when bupropion hydrochloride extended-release tablets (SR) was administered with food to healthy volunteers in three trials. The food effect is not considered clinically significant. Following a single-dose administration of bupropion hydrochloride extended-release tablets (SR) in humans, Cmax of bupropion's metabolite hydroxybupropion occurs approximately 6 hours post-dose and is approximately 10 times the peak level of the parent drug at steady state. The elimination half-life of hydroxybupropion is approximately 20 (±5) hours and its AUC at steady state is about 17 times that of bupropion. The times to peak concentrations for the erythrohydrobupropion and threohydrobupropion metabolites are similar to that of the hydroxybupropion metabolite. However, their elimination half-lives are longer, 33(±10) and 37 (±13) hours, respectively, and steady-state AUCs are 1.5 and 7 times that of bupropion, respectively. •Absorption (Drug B): No absorption available •Volume of distribution (Drug A): No volume of distribution available •Volume of distribution (Drug B): 10 mg/kg (in rats). •Protein binding (Drug A): In vitro tests show that bupropion is 84% bound to human plasma proteins at concentrations up to 200 mcg per mL. The extent of protein binding of the hydroxybupropion metabolite is similar to that for bupropion, whereas the extent of protein binding of the threohydrobupropion metabolite is about half that seen with bupropion. •Protein binding (Drug B): Methylene blue was reported to bind strongly to rabbit plasma (71–77% of bound drug). •Metabolism (Drug A): Bupropion is extensively metabolized in humans. Three metabolites are active: hydroxybupropion, which is formed via hydroxylation of the tert-butyl group of bupropion, and the amino-alcohol isomers, threohydrobupropion and erythrohydrobupropion, which are formed via reduction of the carbonyl group. In vitro findings suggest that CYP2B6 is the principal isoenzyme involved in the formation of hydroxybupropion, while cytochrome P450 enzymes are not involved in the formation of threohydrobupropion. Hydroxybupropion has been shown to have the same affinity as bupropion for the norepinephrine transporter (NET) but approximately 50% of its antidepressant activity despite reaching concentrations of ~10-fold higher than that of the parent drug. Oxidation of the bupropion side chain results in the formation of a glycine conjugate of meta-chlorobenzoic acid, which is then excreted as the major urinary metabolite. The potency and toxicity of the metabolites relative to bupropion have not been fully characterized. However, it has been demonstrated in an antidepressant screening test in mice that hydroxybupropion is one-half as potent as bupropion, while threohydrobupropion and erythrohydrobupropion are 5-fold less potent than bupropion. This may be of clinical importance because the plasma concentrations of the metabolites are as high as or higher than those of bupropion. Bupropion and its metabolites exhibit linear kinetics following chronic administration of 300 to 450 mg per day. •Metabolism (Drug B): Following distribution into tissues, rapidly reduced to leukomethylene blue (leucomethylthioninium chloride). Metabolism to leucomethylene blue may be less efficient in neonates than in older individuals. •Route of elimination (Drug A): Bupropion is extensively metabolized in humans. Oxidation of the bupropion side chain results in the formation of a glycine conjugate of metachlorobenzoic acid, which is then excreted as the major urinary metabolite. Following oral administration of 200 mg of 14C-bupropion in humans, 87% and 10% of the radioactive dose were recovered in the urine and feces, respectively. However, the fraction of the oral dose of bupropion excreted unchanged was only 0.5%, a finding consistent with the extensive metabolism of bupropion. •Route of elimination (Drug B): Excreted in urine and bile. About 75% of an oral dose excreted in urine, primarily as stabilized colorless leukomethylene blue. •Half-life (Drug A): 24 hours •Half-life (Drug B): 5–6.5 hours (after IV dose). •Clearance (Drug A): No clearance available •Clearance (Drug B): 3.0 ± 0.7 L/min. •Toxicity (Drug A): Symptoms of overdose include seizures, hallucinations, loss of consciousness, tachycardia, and cardiac arrest. •Toxicity (Drug B): LD50 = 1180 mg/kg ( Rat ). •Brand Names (Drug A): Aplenzin, Auvelity, Budeprion, Contrave, Forfivo, Wellbutrin, Zyban •Brand Names (Drug B): Hyophen, Phosphasal, Provayblue, Proveblue, Urelle, Uribel, Urimar Reformulated Oct 2013, Urin DS, Urogesic Blue Reformulated Apr 2012, Ustell •Synonyms (Drug A): No synonyms listed •Synonyms (Drug B): Azul de metileno Basic Blue 9 C.I. basic blue 9 Chlorure de méthylthioninium Cloruro de metiltioninio Methylene blue Methylenium ceruleum Methylthioninii chloridum Methylthioninium chloride •Summary (Drug A): Bupropion is a norepinephrine and dopamine reuptake inhibitor used in the treatment of major depressive disorder (MDD), seasonal affective disorder (SAD), and as an aid to smoking cessation. •Summary (Drug B): Methylene blue is an oxidation-reduction agent used for the treatment of pediatric and adult patients with acquired methemoglobinemia.

Bupropion is a dopaminergic agent that is used in the treatment of Parkinson's disease, depression, and smoking cessation. Based on the findings from animal studies, co-administration of bupropion with monoamine oxidase inhibitors may enhance the acute toxicity effects of bupropion, as indicated by an increase in mortality and a decrease in time to death . This interaction applies to both immediate release and sustained release forms of bupropion. The severity of the interaction is major.

Question: Does Bupropion and Methylene blue interact? Information: •Drug A: Bupropion •Drug B: Methylene blue •Severity: MAJOR •Description: The risk or severity of adverse effects can be increased when Methylene blue is combined with Bupropion. •Extended Description: Bupropion is a dopaminergic agent that is used in the treatment of Parkinson's disease, depression, and smoking cessation. Based on the findings from animal studies, co-administration of bupropion with monoamine oxidase inhibitors may enhance the acute toxicity effects of bupropion, as indicated by an increase in mortality and a decrease in time to death . This interaction applies to both immediate release and sustained release forms of bupropion. •Indication (Drug A): Bupropion is indicated for the treatment of major depressive disorder (MDD), seasonal affective disorder (SAD), and as an aid to smoking cessation. When used in combination with naltrexone as the marketed product ContraveⓇ, bupropion is indicated as an adjunct to a reduced-calorie diet and increased physical activity for chronic weight management in adults with an initial body mass index (BMI) of: 30 kg/m^2 or greater (obese) or 27 kg/m^2 or greater (overweight) in the presence of at least one weight-related comorbid condition (e.g., hypertension, type 2 diabetes mellitus, or dyslipidemia). Bupropion is also used off-label as a first-line treatment in patients with ADHD and comorbid bipolar disorder when used as an adjunct to mood stabilizers. •Indication (Drug B): Indicated for the treatment of pediatric and adult patients with acquired methemoglobinemia. Other clinical applications of methylene blue include improvement of hypotension associated with various clinical states, an antiseptic in urinary tract infections, treatment of hypoxia and hyperdynamic circulation in cirrhosis of liver and severe hepatopulmonary syndrome, and treatment of ifofosamide induced neurotoxicity. •Pharmacodynamics (Drug A): Bupropion is chemically unrelated to tricyclic, tetracyclic, selective serotonin re-uptake inhibitors, or other known antidepressant agents. Compared to classical tricyclic antidepressants, Bupropion is a relatively weak inhibitor of the neuronal uptake of norepinephrine and dopamine. In addition, Bupropion does not inhibit monoamine oxidase. Bupropion has been found to be essentially inactive at the serotonin transporter (SERT)(IC50 >10 000 nM), however both bupropion and its primary metabolite hydroxybupropion have been found to block the function of cation-selective serotonin type 3A receptors (5-HT3ARs). Bupropion produces dose-related central nervous system (CNS) stimulant effects in animals, as evidenced by increased locomotor activity, increased rates of responding in various schedule-controlled operant behaviour tasks, and, at high doses, induction of mild stereotyped behaviour. Due to these stimulant effects and selective activity at dopamine and norepinephrine receptors, bupropion has been identified as having an abuse potential. Bupropion has a similar structure to the controlled substance Cathinone, and has been identified as having mild amphetamine-like activity, particularly when inhaled or injected. Bupropion is also known to lower the seizure threshold, making any pre-existing seizure conditions a contraindication to its use. This risk is exacerbated when bupropion is combined with other drugs or substances that lower the seizure threshold, such as cocaine, or in clinical situations that would increase the risk of a seizure such as abrupt alcohol or benzodiazepine withdrawal. As norepinephrine has been shown to have anticonvulsant properties, bupropion's inhibitory effects on NET are thought to contribute to its pro-convulsant activity. Bupropion has been shown to increase blood pressure and pose a risk for exacerbation of unmanaged or pre-existing hypertension, however, clinical trials of bupropion in smokers with CVD have not identified an increased incidence of CV events including stroke or heart attack. In clinical trials, the mean increase in systolic blood pressure associated with the use of bupropion was found to be 1.3 mmHg. •Pharmacodynamics (Drug B): No pharmacodynamics available •Mechanism of action (Drug A): Bupropion is a norepinephrine/dopamine-reuptake inhibitor (NDRI) that exerts its pharmacological effects by weakly inhibiting the enzymes involved in the uptake of the neurotransmitters norepinephrine and dopamine from the synaptic cleft, therefore prolonging their duration of action within the neuronal synapse and the downstream effects of these neurotransmitters. More specifically, bupropion binds to the norepinephrine transporter (NET) and the dopamine transporter (DAT). Bupropion was originally classified as an "atypical" antidepressant because it does not exert the same effects as the classical antidepressants such as Monoamine Oxidase Inhibitors (MAOIs), Tricyclic Antidepressants (TCAs), or Selective Serotonin Reuptake Inhibitors (SSRIs). While it has comparable effectiveness to typical first-line options for the treatment of depression such as SSRIs, bupropion is a unique option for the treatment of MDD as it lacks any clinically relevant serotonergic effects, typical of other mood medications, or any effects on histamine or adrenaline receptors. Lack of activity at these receptors results in a more tolerable side effect profile; bupropion is less likely to cause sexual side effects, sedation, or weight gain as compared to SSRIs or TCAs, for example. When used as an aid to smoking cessation, bupropion is thought to confer its anti-craving and anti-withdrawal effects by inhibiting dopamine reuptake, which is thought to be involved in the reward pathways associated with nicotine, and through the antagonism of the nicotinic acetylcholinergic receptor (AChR), thereby blunting the effects of nicotine. Furthermore, the stimulatory effects produced by bupropion in the central nervous system are similar to nicotine's effects, making low doses of bupropion a suitable option as a nicotine substitute. When used in combination with naltrexone in the marketed product ContraveⓇ for chronic weight management, the two components are thought to have effects on areas of the brain involved in the regulation of food intake. This includes the hypothalamus, which is involved in appetite regulation, and the mesolimbic dopamine circuit, which is involved in reward pathways. Studies have shown that the combined activity of bupropion and naltrexone increase the firing rate of hypothalamic pro-opiomelanocortin (POMC) neurons and blockade of opioid receptor-mediated POMC auto-inhibition, which are associated with a reduction in food intake and increased energy expenditure. This combination was also found to reduce food intake when injected directly into the ventral tegmental area of the mesolimbic circuit in mice, which is an area associated with the regulation of reward pathways. •Mechanism of action (Drug B): Main mechanism of action involves inhibition of nitric oxide synthase and guanylate cyclase. In Alzheimers Disease: a mechanistic study found that methylene blue oxidizes cysteine sulfhydryl groups on tau to keep tau monomeric. One preclinical treatment study in tauopathy mice reported anti-inflammatory or neuroprotective effects mediated by the Nrf2/antioxidant response element (ARE); another reported insoluble tau reduction and a learning and memory benefit when given early. In Methemoglobinemia: Methylene Blue acts by reacting within RBC to form leukomethylene blue, which is a reducing agent of oxidized hemoglobin converting the ferric ion (fe+++) back to its oxygen-carrying ferrous state(fe++). As antimalarial agent: Methylene Blue, a specific inhibitor of P.falciparum glutathione reductase has the potential to reverse CQ resistance and it prevents the polymerization of haem into haemozoin similar to 4-amino-quinoline antimalarials. For ifosfamide induced neurotoxicity: Methylene blue functions as an alternate electron acceptor. It acts to reverse the NADH inhibition caused by gluconeogenesis in the liver while blocking the transformation of chloroethylamine into chloroacetaldehyde. In addition, it inhibits various amine oxidase activities, which also prevents the formation of chloroacetaldehyde. •Absorption (Drug A): Bupropion is currently available in 3 distinct, but bioequivalent formulations: immediate release (IR), sustained-release (SR), and extended-release (XL). Immediate Release Formulation In humans, following oral administration of bupropion hydrochloride tablets, peak plasma bupropion concentrations are usually achieved within 2 hours. IR formulations provide a short duration of action and are therefore generally dosed three times per day. Sustained Release Formulation In humans, following oral administration of bupropion hydrochloride sustained-release tablets (SR), peak plasma concentration (Cmax) of bupropion is usually achieved within 3 hours. SR formulations provide a 12-hour extended release of medication and are therefore generally dosed twice per day. Extended Release Formulation Following single oral administration of bupropion hydrochloride extended-release tablets (XL) to healthy volunteers, the median time to peak plasma concentrations for bupropion was approximately 5 hours. The presence of food did not affect the peak concentration or area under the curve of bupropion. XL formulations provide a 24-hour extended release of medication and are therefore generally dosed once per day/ In a trial comparing chronic dosing with bupropion hydrochloride extended-release tablets (SR) 150 mg twice daily to bupropion immediate-release formulation 100 mg 3 times daily, the steady state Cmax for bupropion after bupropion hydrochloride sustained-release tablets (SR) administration was approximately 85% of those achieved after bupropion immediate-release formulation administration. Exposure (AUC) to bupropion was equivalent for both formulations. Bioequivalence was also demonstrated for all three major active metabolites (i.e., hydroxybupropion, threohydrobupropion and erythrohydrobupropion) for both Cmax and AUC. Thus, at steady state, bupropion hydrochloride sustained-release tablets (SR) given twice daily, and the immediate-release formulation of bupropion given 3 times daily, are essentially bioequivalent for both bupropion and the 3 quantitatively important metabolites. Furthermore, in a study comparing 14-day dosing with bupropion hydrochloride extended-release tablets (XL), 300 mg once-daily to the immediate-release formulation of bupropion at 100 mg 3 times daily, equivalence was demonstrated for peak plasma concentration and area under the curve for bupropion and the three metabolites (hydroxybupropion, threohydrobupropion, and erythrohydrobupropion). Additionally, in a study comparing 14-day dosing with bupropion hydrochloride extended-release tablets (XL) 300 mg once daily to the sustained-release formulation of bupropion at 150 mg 2 times daily, equivalence was demonstrated for peak plasma concentration and area under the curve for bupropion and the three metabolites. Bupropion hydrochloride extended-release tablets (SR) can be taken with or without food. Bupropion Cmax and AUC were increased by 11% to 35% and 16% to 19%, respectively, when bupropion hydrochloride extended-release tablets (SR) was administered with food to healthy volunteers in three trials. The food effect is not considered clinically significant. Following a single-dose administration of bupropion hydrochloride extended-release tablets (SR) in humans, Cmax of bupropion's metabolite hydroxybupropion occurs approximately 6 hours post-dose and is approximately 10 times the peak level of the parent drug at steady state. The elimination half-life of hydroxybupropion is approximately 20 (±5) hours and its AUC at steady state is about 17 times that of bupropion. The times to peak concentrations for the erythrohydrobupropion and threohydrobupropion metabolites are similar to that of the hydroxybupropion metabolite. However, their elimination half-lives are longer, 33(±10) and 37 (±13) hours, respectively, and steady-state AUCs are 1.5 and 7 times that of bupropion, respectively. •Absorption (Drug B): No absorption available •Volume of distribution (Drug A): No volume of distribution available •Volume of distribution (Drug B): 10 mg/kg (in rats). •Protein binding (Drug A): In vitro tests show that bupropion is 84% bound to human plasma proteins at concentrations up to 200 mcg per mL. The extent of protein binding of the hydroxybupropion metabolite is similar to that for bupropion, whereas the extent of protein binding of the threohydrobupropion metabolite is about half that seen with bupropion. •Protein binding (Drug B): Methylene blue was reported to bind strongly to rabbit plasma (71–77% of bound drug). •Metabolism (Drug A): Bupropion is extensively metabolized in humans. Three metabolites are active: hydroxybupropion, which is formed via hydroxylation of the tert-butyl group of bupropion, and the amino-alcohol isomers, threohydrobupropion and erythrohydrobupropion, which are formed via reduction of the carbonyl group. In vitro findings suggest that CYP2B6 is the principal isoenzyme involved in the formation of hydroxybupropion, while cytochrome P450 enzymes are not involved in the formation of threohydrobupropion. Hydroxybupropion has been shown to have the same affinity as bupropion for the norepinephrine transporter (NET) but approximately 50% of its antidepressant activity despite reaching concentrations of ~10-fold higher than that of the parent drug. Oxidation of the bupropion side chain results in the formation of a glycine conjugate of meta-chlorobenzoic acid, which is then excreted as the major urinary metabolite. The potency and toxicity of the metabolites relative to bupropion have not been fully characterized. However, it has been demonstrated in an antidepressant screening test in mice that hydroxybupropion is one-half as potent as bupropion, while threohydrobupropion and erythrohydrobupropion are 5-fold less potent than bupropion. This may be of clinical importance because the plasma concentrations of the metabolites are as high as or higher than those of bupropion. Bupropion and its metabolites exhibit linear kinetics following chronic administration of 300 to 450 mg per day. •Metabolism (Drug B): Following distribution into tissues, rapidly reduced to leukomethylene blue (leucomethylthioninium chloride). Metabolism to leucomethylene blue may be less efficient in neonates than in older individuals. •Route of elimination (Drug A): Bupropion is extensively metabolized in humans. Oxidation of the bupropion side chain results in the formation of a glycine conjugate of metachlorobenzoic acid, which is then excreted as the major urinary metabolite. Following oral administration of 200 mg of 14C-bupropion in humans, 87% and 10% of the radioactive dose were recovered in the urine and feces, respectively. However, the fraction of the oral dose of bupropion excreted unchanged was only 0.5%, a finding consistent with the extensive metabolism of bupropion. •Route of elimination (Drug B): Excreted in urine and bile. About 75% of an oral dose excreted in urine, primarily as stabilized colorless leukomethylene blue. •Half-life (Drug A): 24 hours •Half-life (Drug B): 5–6.5 hours (after IV dose). •Clearance (Drug A): No clearance available •Clearance (Drug B): 3.0 ± 0.7 L/min. •Toxicity (Drug A): Symptoms of overdose include seizures, hallucinations, loss of consciousness, tachycardia, and cardiac arrest. •Toxicity (Drug B): LD50 = 1180 mg/kg ( Rat ). •Brand Names (Drug A): Aplenzin, Auvelity, Budeprion, Contrave, Forfivo, Wellbutrin, Zyban •Brand Names (Drug B): Hyophen, Phosphasal, Provayblue, Proveblue, Urelle, Uribel, Urimar Reformulated Oct 2013, Urin DS, Urogesic Blue Reformulated Apr 2012, Ustell •Synonyms (Drug A): No synonyms listed •Synonyms (Drug B): Azul de metileno Basic Blue 9 C.I. basic blue 9 Chlorure de méthylthioninium Cloruro de metiltioninio Methylene blue Methylenium ceruleum Methylthioninii chloridum Methylthioninium chloride •Summary (Drug A): Bupropion is a norepinephrine and dopamine reuptake inhibitor used in the treatment of major depressive disorder (MDD), seasonal affective disorder (SAD), and as an aid to smoking cessation. •Summary (Drug B): Methylene blue is an oxidation-reduction agent used for the treatment of pediatric and adult patients with acquired methemoglobinemia. Output: Bupropion is a dopaminergic agent that is used in the treatment of Parkinson's disease, depression, and smoking cessation. Based on the findings from animal studies, co-administration of bupropion with monoamine oxidase inhibitors may enhance the acute toxicity effects of bupropion, as indicated by an increase in mortality and a decrease in time to death . This interaction applies to both immediate release and sustained release forms of bupropion. The severity of the interaction is major.

Does Bupropion and Methylnaltrexone interact?

•Drug A: Bupropion •Drug B: Methylnaltrexone •Severity: MINOR •Description: Bupropion may decrease the excretion rate of Methylnaltrexone which could result in a higher serum level. •Extended Description: The renal excretion of drugs is the overall result of a combination of kidney processes that include glomerular filtration, passive diffusion, tubular secretion, and tubular reabsorption. Since two of these mechanisms - tubular secretion and reabsorption - are saturable processes , they are consequently susceptible to competition between multiple substrates excreted by the kidneys. If two or more medications that are mainly renally excreted are co-administered, they may compete for renal elimination; there is a large likelihood that one agent may "out-compete" or saturate the renal excretion mechanisms before the other concomitantly administered agent(s) are excreted. As a result, the elimination of these other concurrently administered agents may be inhibited or otherwise delayed, which could lead to increases in their serum concentrations and the risk, incidence, and/or severity of adverse effects associated with the exposure to such drugs. •Indication (Drug A): Bupropion is indicated for the treatment of major depressive disorder (MDD), seasonal affective disorder (SAD), and as an aid to smoking cessation. When used in combination with naltrexone as the marketed product ContraveⓇ, bupropion is indicated as an adjunct to a reduced-calorie diet and increased physical activity for chronic weight management in adults with an initial body mass index (BMI) of: 30 kg/m^2 or greater (obese) or 27 kg/m^2 or greater (overweight) in the presence of at least one weight-related comorbid condition (e.g., hypertension, type 2 diabetes mellitus, or dyslipidemia). Bupropion is also used off-label as a first-line treatment in patients with ADHD and comorbid bipolar disorder when used as an adjunct to mood stabilizers. •Indication (Drug B): Treatment of opioids induced constipation in palliative patients that are inadequately responding to laxative therapy. •Pharmacodynamics (Drug A): Bupropion is chemically unrelated to tricyclic, tetracyclic, selective serotonin re-uptake inhibitors, or other known antidepressant agents. Compared to classical tricyclic antidepressants, Bupropion is a relatively weak inhibitor of the neuronal uptake of norepinephrine and dopamine. In addition, Bupropion does not inhibit monoamine oxidase. Bupropion has been found to be essentially inactive at the serotonin transporter (SERT)(IC50 >10 000 nM), however both bupropion and its primary metabolite hydroxybupropion have been found to block the function of cation-selective serotonin type 3A receptors (5-HT3ARs). Bupropion produces dose-related central nervous system (CNS) stimulant effects in animals, as evidenced by increased locomotor activity, increased rates of responding in various schedule-controlled operant behaviour tasks, and, at high doses, induction of mild stereotyped behaviour. Due to these stimulant effects and selective activity at dopamine and norepinephrine receptors, bupropion has been identified as having an abuse potential. Bupropion has a similar structure to the controlled substance Cathinone, and has been identified as having mild amphetamine-like activity, particularly when inhaled or injected. Bupropion is also known to lower the seizure threshold, making any pre-existing seizure conditions a contraindication to its use. This risk is exacerbated when bupropion is combined with other drugs or substances that lower the seizure threshold, such as cocaine, or in clinical situations that would increase the risk of a seizure such as abrupt alcohol or benzodiazepine withdrawal. As norepinephrine has been shown to have anticonvulsant properties, bupropion's inhibitory effects on NET are thought to contribute to its pro-convulsant activity. Bupropion has been shown to increase blood pressure and pose a risk for exacerbation of unmanaged or pre-existing hypertension, however, clinical trials of bupropion in smokers with CVD have not identified an increased incidence of CV events including stroke or heart attack. In clinical trials, the mean increase in systolic blood pressure associated with the use of bupropion was found to be 1.3 mmHg. •Pharmacodynamics (Drug B): Use of opioids induces slowing of gastrointestinal motility and transit. Following remifentanil administration, the methylnaltrexone and placebo groups showed no change in pupiliary constriction while the naloxone group showed a marked change over the time interval tested. •Mechanism of action (Drug A): Bupropion is a norepinephrine/dopamine-reuptake inhibitor (NDRI) that exerts its pharmacological effects by weakly inhibiting the enzymes involved in the uptake of the neurotransmitters norepinephrine and dopamine from the synaptic cleft, therefore prolonging their duration of action within the neuronal synapse and the downstream effects of these neurotransmitters. More specifically, bupropion binds to the norepinephrine transporter (NET) and the dopamine transporter (DAT). Bupropion was originally classified as an "atypical" antidepressant because it does not exert the same effects as the classical antidepressants such as Monoamine Oxidase Inhibitors (MAOIs), Tricyclic Antidepressants (TCAs), or Selective Serotonin Reuptake Inhibitors (SSRIs). While it has comparable effectiveness to typical first-line options for the treatment of depression such as SSRIs, bupropion is a unique option for the treatment of MDD as it lacks any clinically relevant serotonergic effects, typical of other mood medications, or any effects on histamine or adrenaline receptors. Lack of activity at these receptors results in a more tolerable side effect profile; bupropion is less likely to cause sexual side effects, sedation, or weight gain as compared to SSRIs or TCAs, for example. When used as an aid to smoking cessation, bupropion is thought to confer its anti-craving and anti-withdrawal effects by inhibiting dopamine reuptake, which is thought to be involved in the reward pathways associated with nicotine, and through the antagonism of the nicotinic acetylcholinergic receptor (AChR), thereby blunting the effects of nicotine. Furthermore, the stimulatory effects produced by bupropion in the central nervous system are similar to nicotine's effects, making low doses of bupropion a suitable option as a nicotine substitute. When used in combination with naltrexone in the marketed product ContraveⓇ for chronic weight management, the two components are thought to have effects on areas of the brain involved in the regulation of food intake. This includes the hypothalamus, which is involved in appetite regulation, and the mesolimbic dopamine circuit, which is involved in reward pathways. Studies have shown that the combined activity of bupropion and naltrexone increase the firing rate of hypothalamic pro-opiomelanocortin (POMC) neurons and blockade of opioid receptor-mediated POMC auto-inhibition, which are associated with a reduction in food intake and increased energy expenditure. This combination was also found to reduce food intake when injected directly into the ventral tegmental area of the mesolimbic circuit in mice, which is an area associated with the regulation of reward pathways. •Mechanism of action (Drug B): Methylnaltrexone is a pheriphally-acting μ-opioid antagonists that acts on the gastrointestinal tract inhibit opioid-induced decrease in gastric motility and transit time. Because methylnaltrexone is a quaternary derivative of naltrexone, it produces its gastrointestinal effects without producing analgesic effects or withdrawal symptoms as it does not cross the blood-brain-barrier. •Absorption (Drug A): Bupropion is currently available in 3 distinct, but bioequivalent formulations: immediate release (IR), sustained-release (SR), and extended-release (XL). Immediate Release Formulation In humans, following oral administration of bupropion hydrochloride tablets, peak plasma bupropion concentrations are usually achieved within 2 hours. IR formulations provide a short duration of action and are therefore generally dosed three times per day. Sustained Release Formulation In humans, following oral administration of bupropion hydrochloride sustained-release tablets (SR), peak plasma concentration (Cmax) of bupropion is usually achieved within 3 hours. SR formulations provide a 12-hour extended release of medication and are therefore generally dosed twice per day. Extended Release Formulation Following single oral administration of bupropion hydrochloride extended-release tablets (XL) to healthy volunteers, the median time to peak plasma concentrations for bupropion was approximately 5 hours. The presence of food did not affect the peak concentration or area under the curve of bupropion. XL formulations provide a 24-hour extended release of medication and are therefore generally dosed once per day/ In a trial comparing chronic dosing with bupropion hydrochloride extended-release tablets (SR) 150 mg twice daily to bupropion immediate-release formulation 100 mg 3 times daily, the steady state Cmax for bupropion after bupropion hydrochloride sustained-release tablets (SR) administration was approximately 85% of those achieved after bupropion immediate-release formulation administration. Exposure (AUC) to bupropion was equivalent for both formulations. Bioequivalence was also demonstrated for all three major active metabolites (i.e., hydroxybupropion, threohydrobupropion and erythrohydrobupropion) for both Cmax and AUC. Thus, at steady state, bupropion hydrochloride sustained-release tablets (SR) given twice daily, and the immediate-release formulation of bupropion given 3 times daily, are essentially bioequivalent for both bupropion and the 3 quantitatively important metabolites. Furthermore, in a study comparing 14-day dosing with bupropion hydrochloride extended-release tablets (XL), 300 mg once-daily to the immediate-release formulation of bupropion at 100 mg 3 times daily, equivalence was demonstrated for peak plasma concentration and area under the curve for bupropion and the three metabolites (hydroxybupropion, threohydrobupropion, and erythrohydrobupropion). Additionally, in a study comparing 14-day dosing with bupropion hydrochloride extended-release tablets (XL) 300 mg once daily to the sustained-release formulation of bupropion at 150 mg 2 times daily, equivalence was demonstrated for peak plasma concentration and area under the curve for bupropion and the three metabolites. Bupropion hydrochloride extended-release tablets (SR) can be taken with or without food. Bupropion Cmax and AUC were increased by 11% to 35% and 16% to 19%, respectively, when bupropion hydrochloride extended-release tablets (SR) was administered with food to healthy volunteers in three trials. The food effect is not considered clinically significant. Following a single-dose administration of bupropion hydrochloride extended-release tablets (SR) in humans, Cmax of bupropion's metabolite hydroxybupropion occurs approximately 6 hours post-dose and is approximately 10 times the peak level of the parent drug at steady state. The elimination half-life of hydroxybupropion is approximately 20 (±5) hours and its AUC at steady state is about 17 times that of bupropion. The times to peak concentrations for the erythrohydrobupropion and threohydrobupropion metabolites are similar to that of the hydroxybupropion metabolite. However, their elimination half-lives are longer, 33(±10) and 37 (±13) hours, respectively, and steady-state AUCs are 1.5 and 7 times that of bupropion, respectively. •Absorption (Drug B): Methylnaltrexone is rapidly absorbed. Tmax (SubQ): 30 minutes (regardless of dose); Cmax, 0.15 mg/kg SubQ dose = 117 ng/mL; AUC24, 0.15 mg/kg SubQ dose = 175 ng·hr/mL; •Volume of distribution (Drug A): No volume of distribution available •Volume of distribution (Drug B): Volume of distribution, steady state = 1.1 L/kg •Protein binding (Drug A): In vitro tests show that bupropion is 84% bound to human plasma proteins at concentrations up to 200 mcg per mL. The extent of protein binding of the hydroxybupropion metabolite is similar to that for bupropion, whereas the extent of protein binding of the threohydrobupropion metabolite is about half that seen with bupropion. •Protein binding (Drug B): 11% to 15% bound to human plasma proteins. •Metabolism (Drug A): Bupropion is extensively metabolized in humans. Three metabolites are active: hydroxybupropion, which is formed via hydroxylation of the tert-butyl group of bupropion, and the amino-alcohol isomers, threohydrobupropion and erythrohydrobupropion, which are formed via reduction of the carbonyl group. In vitro findings suggest that CYP2B6 is the principal isoenzyme involved in the formation of hydroxybupropion, while cytochrome P450 enzymes are not involved in the formation of threohydrobupropion. Hydroxybupropion has been shown to have the same affinity as bupropion for the norepinephrine transporter (NET) but approximately 50% of its antidepressant activity despite reaching concentrations of ~10-fold higher than that of the parent drug. Oxidation of the bupropion side chain results in the formation of a glycine conjugate of meta-chlorobenzoic acid, which is then excreted as the major urinary metabolite. The potency and toxicity of the metabolites relative to bupropion have not been fully characterized. However, it has been demonstrated in an antidepressant screening test in mice that hydroxybupropion is one-half as potent as bupropion, while threohydrobupropion and erythrohydrobupropion are 5-fold less potent than bupropion. This may be of clinical importance because the plasma concentrations of the metabolites are as high as or higher than those of bupropion. Bupropion and its metabolites exhibit linear kinetics following chronic administration of 300 to 450 mg per day. •Metabolism (Drug B): 60% of the dose is metabolized. Conversion to methyl-6-naltrexol isomers (5% of total dose) and methylnaltrexone sulfate (1.3% of total dose) appear to be the primary pathways of metabolism. N‑demethylation of methylnaltrexone to produce naltrexone is not significant. •Route of elimination (Drug A): Bupropion is extensively metabolized in humans. Oxidation of the bupropion side chain results in the formation of a glycine conjugate of metachlorobenzoic acid, which is then excreted as the major urinary metabolite. Following oral administration of 200 mg of 14C-bupropion in humans, 87% and 10% of the radioactive dose were recovered in the urine and feces, respectively. However, the fraction of the oral dose of bupropion excreted unchanged was only 0.5%, a finding consistent with the extensive metabolism of bupropion. •Route of elimination (Drug B): Most of the drug is eliminated as unchanged drug (85% of administered radioactivity). Approximately half of the dose is excreted in the urine and somewhat less in feces. •Half-life (Drug A): 24 hours •Half-life (Drug B): terminal: 8.89 ± 2.59 h (intravenous) terminal: 6.14- 8.83 h (subcutaneous) •Clearance (Drug A): No clearance available •Clearance (Drug B): 10.5 ± 1.5 ml/min/kg (IV) •Toxicity (Drug A): Symptoms of overdose include seizures, hallucinations, loss of consciousness, tachycardia, and cardiac arrest. •Toxicity (Drug B): LD50: 50 mg/kg (primates); Orthostatic hypotension at plasma levels in excess of 1.400 ng/mL. The most common (>5%) adverse reactions reported with methylnaltrexone bromide are abdominal pain, flatulence, nausea, dizziness, diarrhea and hyperhidrosis. •Brand Names (Drug A): Aplenzin, Auvelity, Budeprion, Contrave, Forfivo, Wellbutrin, Zyban •Brand Names (Drug B): Relistor •Synonyms (Drug A): No synonyms listed •Synonyms (Drug B): No synonyms listed •Summary (Drug A): Bupropion is a norepinephrine and dopamine reuptake inhibitor used in the treatment of major depressive disorder (MDD), seasonal affective disorder (SAD), and as an aid to smoking cessation. •Summary (Drug B): Methylnaltrexone is a μ-opioid antagonist used for the treatment of opioid-induced constipation in palliative patients that are inadequately responding to laxative therapy.

The renal excretion of drugs is the overall result of a combination of kidney processes that include glomerular filtration, passive diffusion, tubular secretion, and tubular reabsorption. Since two of these mechanisms - tubular secretion and reabsorption - are saturable processes , they are consequently susceptible to competition between multiple substrates excreted by the kidneys. If two or more medications that are mainly renally excreted are co-administered, they may compete for renal elimination; there is a large likelihood that one agent may "out-compete" or saturate the renal excretion mechanisms before the other concomitantly administered agent(s) are excreted. As a result, the elimination of these other concurrently administered agents may be inhibited or otherwise delayed, which could lead to increases in their serum concentrations and the risk, incidence, and/or severity of adverse effects associated with the exposure to such drugs. The severity of the interaction is minor.

Question: Does Bupropion and Methylnaltrexone interact? Information: •Drug A: Bupropion •Drug B: Methylnaltrexone •Severity: MINOR •Description: Bupropion may decrease the excretion rate of Methylnaltrexone which could result in a higher serum level. •Extended Description: The renal excretion of drugs is the overall result of a combination of kidney processes that include glomerular filtration, passive diffusion, tubular secretion, and tubular reabsorption. Since two of these mechanisms - tubular secretion and reabsorption - are saturable processes , they are consequently susceptible to competition between multiple substrates excreted by the kidneys. If two or more medications that are mainly renally excreted are co-administered, they may compete for renal elimination; there is a large likelihood that one agent may "out-compete" or saturate the renal excretion mechanisms before the other concomitantly administered agent(s) are excreted. As a result, the elimination of these other concurrently administered agents may be inhibited or otherwise delayed, which could lead to increases in their serum concentrations and the risk, incidence, and/or severity of adverse effects associated with the exposure to such drugs. •Indication (Drug A): Bupropion is indicated for the treatment of major depressive disorder (MDD), seasonal affective disorder (SAD), and as an aid to smoking cessation. When used in combination with naltrexone as the marketed product ContraveⓇ, bupropion is indicated as an adjunct to a reduced-calorie diet and increased physical activity for chronic weight management in adults with an initial body mass index (BMI) of: 30 kg/m^2 or greater (obese) or 27 kg/m^2 or greater (overweight) in the presence of at least one weight-related comorbid condition (e.g., hypertension, type 2 diabetes mellitus, or dyslipidemia). Bupropion is also used off-label as a first-line treatment in patients with ADHD and comorbid bipolar disorder when used as an adjunct to mood stabilizers. •Indication (Drug B): Treatment of opioids induced constipation in palliative patients that are inadequately responding to laxative therapy. •Pharmacodynamics (Drug A): Bupropion is chemically unrelated to tricyclic, tetracyclic, selective serotonin re-uptake inhibitors, or other known antidepressant agents. Compared to classical tricyclic antidepressants, Bupropion is a relatively weak inhibitor of the neuronal uptake of norepinephrine and dopamine. In addition, Bupropion does not inhibit monoamine oxidase. Bupropion has been found to be essentially inactive at the serotonin transporter (SERT)(IC50 >10 000 nM), however both bupropion and its primary metabolite hydroxybupropion have been found to block the function of cation-selective serotonin type 3A receptors (5-HT3ARs). Bupropion produces dose-related central nervous system (CNS) stimulant effects in animals, as evidenced by increased locomotor activity, increased rates of responding in various schedule-controlled operant behaviour tasks, and, at high doses, induction of mild stereotyped behaviour. Due to these stimulant effects and selective activity at dopamine and norepinephrine receptors, bupropion has been identified as having an abuse potential. Bupropion has a similar structure to the controlled substance Cathinone, and has been identified as having mild amphetamine-like activity, particularly when inhaled or injected. Bupropion is also known to lower the seizure threshold, making any pre-existing seizure conditions a contraindication to its use. This risk is exacerbated when bupropion is combined with other drugs or substances that lower the seizure threshold, such as cocaine, or in clinical situations that would increase the risk of a seizure such as abrupt alcohol or benzodiazepine withdrawal. As norepinephrine has been shown to have anticonvulsant properties, bupropion's inhibitory effects on NET are thought to contribute to its pro-convulsant activity. Bupropion has been shown to increase blood pressure and pose a risk for exacerbation of unmanaged or pre-existing hypertension, however, clinical trials of bupropion in smokers with CVD have not identified an increased incidence of CV events including stroke or heart attack. In clinical trials, the mean increase in systolic blood pressure associated with the use of bupropion was found to be 1.3 mmHg. •Pharmacodynamics (Drug B): Use of opioids induces slowing of gastrointestinal motility and transit. Following remifentanil administration, the methylnaltrexone and placebo groups showed no change in pupiliary constriction while the naloxone group showed a marked change over the time interval tested. •Mechanism of action (Drug A): Bupropion is a norepinephrine/dopamine-reuptake inhibitor (NDRI) that exerts its pharmacological effects by weakly inhibiting the enzymes involved in the uptake of the neurotransmitters norepinephrine and dopamine from the synaptic cleft, therefore prolonging their duration of action within the neuronal synapse and the downstream effects of these neurotransmitters. More specifically, bupropion binds to the norepinephrine transporter (NET) and the dopamine transporter (DAT). Bupropion was originally classified as an "atypical" antidepressant because it does not exert the same effects as the classical antidepressants such as Monoamine Oxidase Inhibitors (MAOIs), Tricyclic Antidepressants (TCAs), or Selective Serotonin Reuptake Inhibitors (SSRIs). While it has comparable effectiveness to typical first-line options for the treatment of depression such as SSRIs, bupropion is a unique option for the treatment of MDD as it lacks any clinically relevant serotonergic effects, typical of other mood medications, or any effects on histamine or adrenaline receptors. Lack of activity at these receptors results in a more tolerable side effect profile; bupropion is less likely to cause sexual side effects, sedation, or weight gain as compared to SSRIs or TCAs, for example. When used as an aid to smoking cessation, bupropion is thought to confer its anti-craving and anti-withdrawal effects by inhibiting dopamine reuptake, which is thought to be involved in the reward pathways associated with nicotine, and through the antagonism of the nicotinic acetylcholinergic receptor (AChR), thereby blunting the effects of nicotine. Furthermore, the stimulatory effects produced by bupropion in the central nervous system are similar to nicotine's effects, making low doses of bupropion a suitable option as a nicotine substitute. When used in combination with naltrexone in the marketed product ContraveⓇ for chronic weight management, the two components are thought to have effects on areas of the brain involved in the regulation of food intake. This includes the hypothalamus, which is involved in appetite regulation, and the mesolimbic dopamine circuit, which is involved in reward pathways. Studies have shown that the combined activity of bupropion and naltrexone increase the firing rate of hypothalamic pro-opiomelanocortin (POMC) neurons and blockade of opioid receptor-mediated POMC auto-inhibition, which are associated with a reduction in food intake and increased energy expenditure. This combination was also found to reduce food intake when injected directly into the ventral tegmental area of the mesolimbic circuit in mice, which is an area associated with the regulation of reward pathways. •Mechanism of action (Drug B): Methylnaltrexone is a pheriphally-acting μ-opioid antagonists that acts on the gastrointestinal tract inhibit opioid-induced decrease in gastric motility and transit time. Because methylnaltrexone is a quaternary derivative of naltrexone, it produces its gastrointestinal effects without producing analgesic effects or withdrawal symptoms as it does not cross the blood-brain-barrier. •Absorption (Drug A): Bupropion is currently available in 3 distinct, but bioequivalent formulations: immediate release (IR), sustained-release (SR), and extended-release (XL). Immediate Release Formulation In humans, following oral administration of bupropion hydrochloride tablets, peak plasma bupropion concentrations are usually achieved within 2 hours. IR formulations provide a short duration of action and are therefore generally dosed three times per day. Sustained Release Formulation In humans, following oral administration of bupropion hydrochloride sustained-release tablets (SR), peak plasma concentration (Cmax) of bupropion is usually achieved within 3 hours. SR formulations provide a 12-hour extended release of medication and are therefore generally dosed twice per day. Extended Release Formulation Following single oral administration of bupropion hydrochloride extended-release tablets (XL) to healthy volunteers, the median time to peak plasma concentrations for bupropion was approximately 5 hours. The presence of food did not affect the peak concentration or area under the curve of bupropion. XL formulations provide a 24-hour extended release of medication and are therefore generally dosed once per day/ In a trial comparing chronic dosing with bupropion hydrochloride extended-release tablets (SR) 150 mg twice daily to bupropion immediate-release formulation 100 mg 3 times daily, the steady state Cmax for bupropion after bupropion hydrochloride sustained-release tablets (SR) administration was approximately 85% of those achieved after bupropion immediate-release formulation administration. Exposure (AUC) to bupropion was equivalent for both formulations. Bioequivalence was also demonstrated for all three major active metabolites (i.e., hydroxybupropion, threohydrobupropion and erythrohydrobupropion) for both Cmax and AUC. Thus, at steady state, bupropion hydrochloride sustained-release tablets (SR) given twice daily, and the immediate-release formulation of bupropion given 3 times daily, are essentially bioequivalent for both bupropion and the 3 quantitatively important metabolites. Furthermore, in a study comparing 14-day dosing with bupropion hydrochloride extended-release tablets (XL), 300 mg once-daily to the immediate-release formulation of bupropion at 100 mg 3 times daily, equivalence was demonstrated for peak plasma concentration and area under the curve for bupropion and the three metabolites (hydroxybupropion, threohydrobupropion, and erythrohydrobupropion). Additionally, in a study comparing 14-day dosing with bupropion hydrochloride extended-release tablets (XL) 300 mg once daily to the sustained-release formulation of bupropion at 150 mg 2 times daily, equivalence was demonstrated for peak plasma concentration and area under the curve for bupropion and the three metabolites. Bupropion hydrochloride extended-release tablets (SR) can be taken with or without food. Bupropion Cmax and AUC were increased by 11% to 35% and 16% to 19%, respectively, when bupropion hydrochloride extended-release tablets (SR) was administered with food to healthy volunteers in three trials. The food effect is not considered clinically significant. Following a single-dose administration of bupropion hydrochloride extended-release tablets (SR) in humans, Cmax of bupropion's metabolite hydroxybupropion occurs approximately 6 hours post-dose and is approximately 10 times the peak level of the parent drug at steady state. The elimination half-life of hydroxybupropion is approximately 20 (±5) hours and its AUC at steady state is about 17 times that of bupropion. The times to peak concentrations for the erythrohydrobupropion and threohydrobupropion metabolites are similar to that of the hydroxybupropion metabolite. However, their elimination half-lives are longer, 33(±10) and 37 (±13) hours, respectively, and steady-state AUCs are 1.5 and 7 times that of bupropion, respectively. •Absorption (Drug B): Methylnaltrexone is rapidly absorbed. Tmax (SubQ): 30 minutes (regardless of dose); Cmax, 0.15 mg/kg SubQ dose = 117 ng/mL; AUC24, 0.15 mg/kg SubQ dose = 175 ng·hr/mL; •Volume of distribution (Drug A): No volume of distribution available •Volume of distribution (Drug B): Volume of distribution, steady state = 1.1 L/kg •Protein binding (Drug A): In vitro tests show that bupropion is 84% bound to human plasma proteins at concentrations up to 200 mcg per mL. The extent of protein binding of the hydroxybupropion metabolite is similar to that for bupropion, whereas the extent of protein binding of the threohydrobupropion metabolite is about half that seen with bupropion. •Protein binding (Drug B): 11% to 15% bound to human plasma proteins. •Metabolism (Drug A): Bupropion is extensively metabolized in humans. Three metabolites are active: hydroxybupropion, which is formed via hydroxylation of the tert-butyl group of bupropion, and the amino-alcohol isomers, threohydrobupropion and erythrohydrobupropion, which are formed via reduction of the carbonyl group. In vitro findings suggest that CYP2B6 is the principal isoenzyme involved in the formation of hydroxybupropion, while cytochrome P450 enzymes are not involved in the formation of threohydrobupropion. Hydroxybupropion has been shown to have the same affinity as bupropion for the norepinephrine transporter (NET) but approximately 50% of its antidepressant activity despite reaching concentrations of ~10-fold higher than that of the parent drug. Oxidation of the bupropion side chain results in the formation of a glycine conjugate of meta-chlorobenzoic acid, which is then excreted as the major urinary metabolite. The potency and toxicity of the metabolites relative to bupropion have not been fully characterized. However, it has been demonstrated in an antidepressant screening test in mice that hydroxybupropion is one-half as potent as bupropion, while threohydrobupropion and erythrohydrobupropion are 5-fold less potent than bupropion. This may be of clinical importance because the plasma concentrations of the metabolites are as high as or higher than those of bupropion. Bupropion and its metabolites exhibit linear kinetics following chronic administration of 300 to 450 mg per day. •Metabolism (Drug B): 60% of the dose is metabolized. Conversion to methyl-6-naltrexol isomers (5% of total dose) and methylnaltrexone sulfate (1.3% of total dose) appear to be the primary pathways of metabolism. N‑demethylation of methylnaltrexone to produce naltrexone is not significant. •Route of elimination (Drug A): Bupropion is extensively metabolized in humans. Oxidation of the bupropion side chain results in the formation of a glycine conjugate of metachlorobenzoic acid, which is then excreted as the major urinary metabolite. Following oral administration of 200 mg of 14C-bupropion in humans, 87% and 10% of the radioactive dose were recovered in the urine and feces, respectively. However, the fraction of the oral dose of bupropion excreted unchanged was only 0.5%, a finding consistent with the extensive metabolism of bupropion. •Route of elimination (Drug B): Most of the drug is eliminated as unchanged drug (85% of administered radioactivity). Approximately half of the dose is excreted in the urine and somewhat less in feces. •Half-life (Drug A): 24 hours •Half-life (Drug B): terminal: 8.89 ± 2.59 h (intravenous) terminal: 6.14- 8.83 h (subcutaneous) •Clearance (Drug A): No clearance available •Clearance (Drug B): 10.5 ± 1.5 ml/min/kg (IV) •Toxicity (Drug A): Symptoms of overdose include seizures, hallucinations, loss of consciousness, tachycardia, and cardiac arrest. •Toxicity (Drug B): LD50: 50 mg/kg (primates); Orthostatic hypotension at plasma levels in excess of 1.400 ng/mL. The most common (>5%) adverse reactions reported with methylnaltrexone bromide are abdominal pain, flatulence, nausea, dizziness, diarrhea and hyperhidrosis. •Brand Names (Drug A): Aplenzin, Auvelity, Budeprion, Contrave, Forfivo, Wellbutrin, Zyban •Brand Names (Drug B): Relistor •Synonyms (Drug A): No synonyms listed •Synonyms (Drug B): No synonyms listed •Summary (Drug A): Bupropion is a norepinephrine and dopamine reuptake inhibitor used in the treatment of major depressive disorder (MDD), seasonal affective disorder (SAD), and as an aid to smoking cessation. •Summary (Drug B): Methylnaltrexone is a μ-opioid antagonist used for the treatment of opioid-induced constipation in palliative patients that are inadequately responding to laxative therapy. Output: The renal excretion of drugs is the overall result of a combination of kidney processes that include glomerular filtration, passive diffusion, tubular secretion, and tubular reabsorption. Since two of these mechanisms - tubular secretion and reabsorption - are saturable processes , they are consequently susceptible to competition between multiple substrates excreted by the kidneys. If two or more medications that are mainly renally excreted are co-administered, they may compete for renal elimination; there is a large likelihood that one agent may "out-compete" or saturate the renal excretion mechanisms before the other concomitantly administered agent(s) are excreted. As a result, the elimination of these other concurrently administered agents may be inhibited or otherwise delayed, which could lead to increases in their serum concentrations and the risk, incidence, and/or severity of adverse effects associated with the exposure to such drugs. The severity of the interaction is minor.

Does Bupropion and Methylphenidate interact?

•Drug A: Bupropion •Drug B: Methylphenidate •Severity: MODERATE •Description: The risk or severity of seizure can be increased when Bupropion is combined with Methylphenidate. •Extended Description: Bupropion carries a dose-dependent risk of seizure1 that may be further exacerbated when combined with other medications that can reduce the seizure threshold (i.e. increase the risk of seizure), such as the affected drug. This risk may be also compounded by patient-specific factors that may increase the risk of seizure such as metabolic disorders and illicit drug use. •Indication (Drug A): Bupropion is indicated for the treatment of major depressive disorder (MDD), seasonal affective disorder (SAD), and as an aid to smoking cessation. When used in combination with naltrexone as the marketed product ContraveⓇ, bupropion is indicated as an adjunct to a reduced-calorie diet and increased physical activity for chronic weight management in adults with an initial body mass index (BMI) of: 30 kg/m^2 or greater (obese) or 27 kg/m^2 or greater (overweight) in the presence of at least one weight-related comorbid condition (e.g., hypertension, type 2 diabetes mellitus, or dyslipidemia). Bupropion is also used off-label as a first-line treatment in patients with ADHD and comorbid bipolar disorder when used as an adjunct to mood stabilizers. •Indication (Drug B): Methylphenidate is indicated for the treatment of Attention Deficit Hyperactivity Disorder (ADHD) in patients 6 years of age and older and for the treatment of narcolepsy. •Pharmacodynamics (Drug A): Bupropion is chemically unrelated to tricyclic, tetracyclic, selective serotonin re-uptake inhibitors, or other known antidepressant agents. Compared to classical tricyclic antidepressants, Bupropion is a relatively weak inhibitor of the neuronal uptake of norepinephrine and dopamine. In addition, Bupropion does not inhibit monoamine oxidase. Bupropion has been found to be essentially inactive at the serotonin transporter (SERT)(IC50 >10 000 nM), however both bupropion and its primary metabolite hydroxybupropion have been found to block the function of cation-selective serotonin type 3A receptors (5-HT3ARs). Bupropion produces dose-related central nervous system (CNS) stimulant effects in animals, as evidenced by increased locomotor activity, increased rates of responding in various schedule-controlled operant behaviour tasks, and, at high doses, induction of mild stereotyped behaviour. Due to these stimulant effects and selective activity at dopamine and norepinephrine receptors, bupropion has been identified as having an abuse potential. Bupropion has a similar structure to the controlled substance Cathinone, and has been identified as having mild amphetamine-like activity, particularly when inhaled or injected. Bupropion is also known to lower the seizure threshold, making any pre-existing seizure conditions a contraindication to its use. This risk is exacerbated when bupropion is combined with other drugs or substances that lower the seizure threshold, such as cocaine, or in clinical situations that would increase the risk of a seizure such as abrupt alcohol or benzodiazepine withdrawal. As norepinephrine has been shown to have anticonvulsant properties, bupropion's inhibitory effects on NET are thought to contribute to its pro-convulsant activity. Bupropion has been shown to increase blood pressure and pose a risk for exacerbation of unmanaged or pre-existing hypertension, however, clinical trials of bupropion in smokers with CVD have not identified an increased incidence of CV events including stroke or heart attack. In clinical trials, the mean increase in systolic blood pressure associated with the use of bupropion was found to be 1.3 mmHg. •Pharmacodynamics (Drug B): Methylphenidate is a racemic mixture comprised of the d- and l-isomers. The d-isomer is more pharmacologically active than the l-isomer. Radioligand binding studies demonstrate that binding of methylphenidate in the brain is localized to dopamine-rich areas, in particular in the prefrontal cortex which has been demonstrated to play a prominent role in ADHD pathophysiology. In a number of animal models, methylphenidate enhances locomotor activity and induces stereotypic behaviours. •Mechanism of action (Drug A): Bupropion is a norepinephrine/dopamine-reuptake inhibitor (NDRI) that exerts its pharmacological effects by weakly inhibiting the enzymes involved in the uptake of the neurotransmitters norepinephrine and dopamine from the synaptic cleft, therefore prolonging their duration of action within the neuronal synapse and the downstream effects of these neurotransmitters. More specifically, bupropion binds to the norepinephrine transporter (NET) and the dopamine transporter (DAT). Bupropion was originally classified as an "atypical" antidepressant because it does not exert the same effects as the classical antidepressants such as Monoamine Oxidase Inhibitors (MAOIs), Tricyclic Antidepressants (TCAs), or Selective Serotonin Reuptake Inhibitors (SSRIs). While it has comparable effectiveness to typical first-line options for the treatment of depression such as SSRIs, bupropion is a unique option for the treatment of MDD as it lacks any clinically relevant serotonergic effects, typical of other mood medications, or any effects on histamine or adrenaline receptors. Lack of activity at these receptors results in a more tolerable side effect profile; bupropion is less likely to cause sexual side effects, sedation, or weight gain as compared to SSRIs or TCAs, for example. When used as an aid to smoking cessation, bupropion is thought to confer its anti-craving and anti-withdrawal effects by inhibiting dopamine reuptake, which is thought to be involved in the reward pathways associated with nicotine, and through the antagonism of the nicotinic acetylcholinergic receptor (AChR), thereby blunting the effects of nicotine. Furthermore, the stimulatory effects produced by bupropion in the central nervous system are similar to nicotine's effects, making low doses of bupropion a suitable option as a nicotine substitute. When used in combination with naltrexone in the marketed product ContraveⓇ for chronic weight management, the two components are thought to have effects on areas of the brain involved in the regulation of food intake. This includes the hypothalamus, which is involved in appetite regulation, and the mesolimbic dopamine circuit, which is involved in reward pathways. Studies have shown that the combined activity of bupropion and naltrexone increase the firing rate of hypothalamic pro-opiomelanocortin (POMC) neurons and blockade of opioid receptor-mediated POMC auto-inhibition, which are associated with a reduction in food intake and increased energy expenditure. This combination was also found to reduce food intake when injected directly into the ventral tegmental area of the mesolimbic circuit in mice, which is an area associated with the regulation of reward pathways. •Mechanism of action (Drug B): While its exact mechanism is unclear, methylphenidate (MPH) has been shown to act as a norepinephrine and dopamine reuptake inhibitor (NDRI), thereby increasing the presence of these neurotransmitters in the extraneuronal space and prolonging their action. There is a dose-related effect of psychostimulants on receptor stimulation, where higher doses are shown to increase norepinephrine (NE) and dopamine (DA) efflux throughout the brain which can result in impaired cognition and locomotor-activating effects. In contrast, low doses are found to selectively activate NE and DE neurotransmission within the prefrontal cortex which is an area of the brain thought to play a prominent role in ADHD pathophysiology, thereby improving clinical efficacy and preventing side effects. The lower doses used to treat ADHD are not associated with the locomotor-activating effects associated with higher doses and instead reduce movement, impulsivity, and increase cognitive function including sustained attention and working memory. Methylphenidate's beneficial effects in sustaining attention have also been shown to be mediated by alpha-1 adrenergic receptor activity. Clinical findings have shown that children with ADHD have an abnormality in the dopamine transporter gene (DAT1), the D4 receptor gene (DRD-4), and/or the D2 receptor gene that may be at least partly overcome by the dopaminergic effects of methylphenidate, suggesting a possible mode of action. •Absorption (Drug A): Bupropion is currently available in 3 distinct, but bioequivalent formulations: immediate release (IR), sustained-release (SR), and extended-release (XL). Immediate Release Formulation In humans, following oral administration of bupropion hydrochloride tablets, peak plasma bupropion concentrations are usually achieved within 2 hours. IR formulations provide a short duration of action and are therefore generally dosed three times per day. Sustained Release Formulation In humans, following oral administration of bupropion hydrochloride sustained-release tablets (SR), peak plasma concentration (Cmax) of bupropion is usually achieved within 3 hours. SR formulations provide a 12-hour extended release of medication and are therefore generally dosed twice per day. Extended Release Formulation Following single oral administration of bupropion hydrochloride extended-release tablets (XL) to healthy volunteers, the median time to peak plasma concentrations for bupropion was approximately 5 hours. The presence of food did not affect the peak concentration or area under the curve of bupropion. XL formulations provide a 24-hour extended release of medication and are therefore generally dosed once per day/ In a trial comparing chronic dosing with bupropion hydrochloride extended-release tablets (SR) 150 mg twice daily to bupropion immediate-release formulation 100 mg 3 times daily, the steady state Cmax for bupropion after bupropion hydrochloride sustained-release tablets (SR) administration was approximately 85% of those achieved after bupropion immediate-release formulation administration. Exposure (AUC) to bupropion was equivalent for both formulations. Bioequivalence was also demonstrated for all three major active metabolites (i.e., hydroxybupropion, threohydrobupropion and erythrohydrobupropion) for both Cmax and AUC. Thus, at steady state, bupropion hydrochloride sustained-release tablets (SR) given twice daily, and the immediate-release formulation of bupropion given 3 times daily, are essentially bioequivalent for both bupropion and the 3 quantitatively important metabolites. Furthermore, in a study comparing 14-day dosing with bupropion hydrochloride extended-release tablets (XL), 300 mg once-daily to the immediate-release formulation of bupropion at 100 mg 3 times daily, equivalence was demonstrated for peak plasma concentration and area under the curve for bupropion and the three metabolites (hydroxybupropion, threohydrobupropion, and erythrohydrobupropion). Additionally, in a study comparing 14-day dosing with bupropion hydrochloride extended-release tablets (XL) 300 mg once daily to the sustained-release formulation of bupropion at 150 mg 2 times daily, equivalence was demonstrated for peak plasma concentration and area under the curve for bupropion and the three metabolites. Bupropion hydrochloride extended-release tablets (SR) can be taken with or without food. Bupropion Cmax and AUC were increased by 11% to 35% and 16% to 19%, respectively, when bupropion hydrochloride extended-release tablets (SR) was administered with food to healthy volunteers in three trials. The food effect is not considered clinically significant. Following a single-dose administration of bupropion hydrochloride extended-release tablets (SR) in humans, Cmax of bupropion's metabolite hydroxybupropion occurs approximately 6 hours post-dose and is approximately 10 times the peak level of the parent drug at steady state. The elimination half-life of hydroxybupropion is approximately 20 (±5) hours and its AUC at steady state is about 17 times that of bupropion. The times to peak concentrations for the erythrohydrobupropion and threohydrobupropion metabolites are similar to that of the hydroxybupropion metabolite. However, their elimination half-lives are longer, 33(±10) and 37 (±13) hours, respectively, and steady-state AUCs are 1.5 and 7 times that of bupropion, respectively. •Absorption (Drug B): Concerta®: Methylphenidate is readily absorbed. Following oral administration of Concerta, plasma methylhphenidate concentrations reach an initial maximum at about 1 hour followed by gradual ascending concentrations over the next 5-9 hours. Mean times to reach peak plasma concentrations across all doses of Concerta occurred between 6-10 hours. Once daily dosing minimizes the fluctuations between peak and trough concentrations associated with multiple doses of immediate-release methylphenidate treatments. Depending on the doses provided, Cmax was found to range from 6.0-15.0ng/mL, Tmax ranged from 8.1-9.4h, and AUC ranged from 50.4-121.5 ng·h/mL in children. When provided as Concerta®, methylphenidate is released through the patented Osmotic Controlled-Release Oral Delivery (OROS) system where 22% of the dose is provided as an immediate release and 78% is provided through a gradual release. OROS is comprised of an osmotically active trilayer core surrounded by a semipermeable membrane with an immediate-release drug overcoat. Within an aqueous environment, such as the stomach, the drug overcoat, which consists of 22% of the dose, dissolves within one hour, providing an initial immediate-release formulation of methylphenidate. Water then permeates through the membrane into the tablet core where the osmotically active polymer excipients expand, allowing methylphenidate to release slowly through the orifice over a period of 6-7 hours. Concerta also provides a sustained 10-12 hour effect, allowing for once-daily dosing. Biphentin®: Methylphenidate is rapidly and extensively absorbed following oral administration, with peak blood levels obtained in 1-3 hours. When provided as Biphentin®, methylphenidate is released through a multi-layer release delivery system (MLRTM) where 40% of the dose is provided as an immediate release and 60% is provided through a gradual release. Biphentin was designed to be an alternative to separate doses of immediate-release (IR) methylphenidate by providing a biphasic concentration-time profile when given as a single dose. The MLRTM release system allows for a sustained effect for 10-12 hours, allowing for once-daily dosing that covers the major times that ADHD impairment might occur (such as school, homework periods, during the workday, etc). Methylphenidate (immediate release): Methylphenidate hydrochloride is rapidly and extensively absorbed from the tablets following oral administration; however, owing to extensive first-pass metabolism, bioavailability is low (approx. 30%) and large individual differences exist (11-52%). In one study, the administration of methylphenidate hydrochloride with food accelerated absorption but had no effect on the amount absorbed. Peak plasma concentrations of 10.8 and 7.8 ng/mL were observed, on average, 2 hours after administration of 0.30 mg/kg in children and adults, respectively. Peak plasma concentrations showed marked variability between subjects. Both the area under the concentration-time curve (AUC), and the peak plasma concentrations (Cmax) showed dose-proportionality. •Volume of distribution (Drug A): No volume of distribution available •Volume of distribution (Drug B): Concerta: Plasma methylphenidate concentrations in adults decline bi-exponentially following oral administration. Biphentin: The apparent distribution volume of methylphenidate in children is approximately 20 L/kg, with substantial variability (11 to 33 L/kg). Methylphenidate (immediate release): The apparent distribution volume of methylphenidate in children was approximately 20 L/kg, with substantial variability (11-33 L/kg). The volume of distribution after an intravenous dose (Vss) is 2.23 L/kg for the racemate in healthy adult volunteers. •Protein binding (Drug A): In vitro tests show that bupropion is 84% bound to human plasma proteins at concentrations up to 200 mcg per mL. The extent of protein binding of the hydroxybupropion metabolite is similar to that for bupropion, whereas the extent of protein binding of the threohydrobupropion metabolite is about half that seen with bupropion. •Protein binding (Drug B): Concerta: In humans, 15 ± 5% of methylphenidate in the blood is bound to plasma proteins. Biphentin: In blood, methylphenidate and its metabolites are distributed between plasma (57%) and erythrocytes (43%). Methylphenidate and its metabolites exhibit low plasma protein binding (approximately 15%). Methylphenidate (immediate release): In blood, methylphenidate and its metabolites are distributed between plasma (57%) and erythrocytes (43%). Methylphenidate and its metabolites exhibit low plasma protein binding (approx. 15%). •Metabolism (Drug A): Bupropion is extensively metabolized in humans. Three metabolites are active: hydroxybupropion, which is formed via hydroxylation of the tert-butyl group of bupropion, and the amino-alcohol isomers, threohydrobupropion and erythrohydrobupropion, which are formed via reduction of the carbonyl group. In vitro findings suggest that CYP2B6 is the principal isoenzyme involved in the formation of hydroxybupropion, while cytochrome P450 enzymes are not involved in the formation of threohydrobupropion. Hydroxybupropion has been shown to have the same affinity as bupropion for the norepinephrine transporter (NET) but approximately 50% of its antidepressant activity despite reaching concentrations of ~10-fold higher than that of the parent drug. Oxidation of the bupropion side chain results in the formation of a glycine conjugate of meta-chlorobenzoic acid, which is then excreted as the major urinary metabolite. The potency and toxicity of the metabolites relative to bupropion have not been fully characterized. However, it has been demonstrated in an antidepressant screening test in mice that hydroxybupropion is one-half as potent as bupropion, while threohydrobupropion and erythrohydrobupropion are 5-fold less potent than bupropion. This may be of clinical importance because the plasma concentrations of the metabolites are as high as or higher than those of bupropion. Bupropion and its metabolites exhibit linear kinetics following chronic administration of 300 to 450 mg per day. •Metabolism (Drug B): Methylphenidate is hepatically metabolized. More specifically, it is rapidly and extensively metabolized by carboxylesterase CES1A1. Via this enzyme, methylphenidate undergoes de-esterification to ritalinic acid (a-phenyl-2-piperidine acetic acid, PPAA), which has little to no pharmacologic activity. •Route of elimination (Drug A): Bupropion is extensively metabolized in humans. Oxidation of the bupropion side chain results in the formation of a glycine conjugate of metachlorobenzoic acid, which is then excreted as the major urinary metabolite. Following oral administration of 200 mg of 14C-bupropion in humans, 87% and 10% of the radioactive dose were recovered in the urine and feces, respectively. However, the fraction of the oral dose of bupropion excreted unchanged was only 0.5%, a finding consistent with the extensive metabolism of bupropion. •Route of elimination (Drug B): After oral administration of an immediate release formulation of methylphenidate, 78%-97% of the dose is excreted in the urine and 1%-3% in the feces in the form of metabolites within 48-96 hours. Only small quantities (<1%) of unchanged methylphenidate appear in the urine. Most of the dose is excreted in the urine as ritalinic acid (60%-86%), the remainder being accounted for by minor metabolites. •Half-life (Drug A): 24 hours •Half-life (Drug B): Concerta: The half-life of methylphenidate in adults following oral administration of Concerta® was approximately 3.5 h. Biphentin: Methylphenidate is eliminated from plasma with a mean half-life of 2.4 hours in children and 2.1 hours in adults. Methylphenidate (immediate release): Methylphenidate is eliminated from the plasma with a mean half-life of 2.4 hours in children and 2.1 hours in adults. •Clearance (Drug A): No clearance available •Clearance (Drug B): The apparent mean systemic clearance after an oral dose is 10.2 and 10.5 L/h/kg in children and adults, respectively for a 0.3 mg/kg dose, and 0.565 L/h/kg after an intravenous dose of the racemate in healthy adult volunteers. •Toxicity (Drug A): Symptoms of overdose include seizures, hallucinations, loss of consciousness, tachycardia, and cardiac arrest. •Toxicity (Drug B): Symptoms of overdose include vomiting, agitation, tremors, hyperreflexia, muscle twitching, convulsions (may be followed by coma), euphoria, confusion, hallucinations, delirium, sweating, flushing, headache, hyperpyrexia, tachycardia, palpitations, cardiac arrhythmias, hypertension, mydriasis, and dryness of mucous membranes. LD 50 =190mg/kg (orally in mice) •Brand Names (Drug A): Aplenzin, Auvelity, Budeprion, Contrave, Forfivo, Wellbutrin, Zyban •Brand Names (Drug B): Aptensio, Biphentin, Concerta, Cotempla, Daytrana, Foquest, Jornay, Metadate, Methylin, Quillichew, Quillivant, Relexxii, Ritalin •Synonyms (Drug A): No synonyms listed •Synonyms (Drug B): Methyl phenidylacetate Methylphenidan Methylphenidate Methylphenidatum Metilfenidato •Summary (Drug A): Bupropion is a norepinephrine and dopamine reuptake inhibitor used in the treatment of major depressive disorder (MDD), seasonal affective disorder (SAD), and as an aid to smoking cessation. •Summary (Drug B): Methylphenidate is a stimulant used in the management of Attention Deficit Hyperactivity Disorder (ADHD).

Bupropion carries a dose-dependent risk of seizure1 that may be further exacerbated when combined with other medications that can reduce the seizure threshold (i.e. increase the risk of seizure), such as the affected drug. This risk may be also compounded by patient-specific factors that may increase the risk of seizure such as metabolic disorders and illicit drug use. The severity of the interaction is moderate.

Question: Does Bupropion and Methylphenidate interact? Information: •Drug A: Bupropion •Drug B: Methylphenidate •Severity: MODERATE •Description: The risk or severity of seizure can be increased when Bupropion is combined with Methylphenidate. •Extended Description: Bupropion carries a dose-dependent risk of seizure1 that may be further exacerbated when combined with other medications that can reduce the seizure threshold (i.e. increase the risk of seizure), such as the affected drug. This risk may be also compounded by patient-specific factors that may increase the risk of seizure such as metabolic disorders and illicit drug use. •Indication (Drug A): Bupropion is indicated for the treatment of major depressive disorder (MDD), seasonal affective disorder (SAD), and as an aid to smoking cessation. When used in combination with naltrexone as the marketed product ContraveⓇ, bupropion is indicated as an adjunct to a reduced-calorie diet and increased physical activity for chronic weight management in adults with an initial body mass index (BMI) of: 30 kg/m^2 or greater (obese) or 27 kg/m^2 or greater (overweight) in the presence of at least one weight-related comorbid condition (e.g., hypertension, type 2 diabetes mellitus, or dyslipidemia). Bupropion is also used off-label as a first-line treatment in patients with ADHD and comorbid bipolar disorder when used as an adjunct to mood stabilizers. •Indication (Drug B): Methylphenidate is indicated for the treatment of Attention Deficit Hyperactivity Disorder (ADHD) in patients 6 years of age and older and for the treatment of narcolepsy. •Pharmacodynamics (Drug A): Bupropion is chemically unrelated to tricyclic, tetracyclic, selective serotonin re-uptake inhibitors, or other known antidepressant agents. Compared to classical tricyclic antidepressants, Bupropion is a relatively weak inhibitor of the neuronal uptake of norepinephrine and dopamine. In addition, Bupropion does not inhibit monoamine oxidase. Bupropion has been found to be essentially inactive at the serotonin transporter (SERT)(IC50 >10 000 nM), however both bupropion and its primary metabolite hydroxybupropion have been found to block the function of cation-selective serotonin type 3A receptors (5-HT3ARs). Bupropion produces dose-related central nervous system (CNS) stimulant effects in animals, as evidenced by increased locomotor activity, increased rates of responding in various schedule-controlled operant behaviour tasks, and, at high doses, induction of mild stereotyped behaviour. Due to these stimulant effects and selective activity at dopamine and norepinephrine receptors, bupropion has been identified as having an abuse potential. Bupropion has a similar structure to the controlled substance Cathinone, and has been identified as having mild amphetamine-like activity, particularly when inhaled or injected. Bupropion is also known to lower the seizure threshold, making any pre-existing seizure conditions a contraindication to its use. This risk is exacerbated when bupropion is combined with other drugs or substances that lower the seizure threshold, such as cocaine, or in clinical situations that would increase the risk of a seizure such as abrupt alcohol or benzodiazepine withdrawal. As norepinephrine has been shown to have anticonvulsant properties, bupropion's inhibitory effects on NET are thought to contribute to its pro-convulsant activity. Bupropion has been shown to increase blood pressure and pose a risk for exacerbation of unmanaged or pre-existing hypertension, however, clinical trials of bupropion in smokers with CVD have not identified an increased incidence of CV events including stroke or heart attack. In clinical trials, the mean increase in systolic blood pressure associated with the use of bupropion was found to be 1.3 mmHg. •Pharmacodynamics (Drug B): Methylphenidate is a racemic mixture comprised of the d- and l-isomers. The d-isomer is more pharmacologically active than the l-isomer. Radioligand binding studies demonstrate that binding of methylphenidate in the brain is localized to dopamine-rich areas, in particular in the prefrontal cortex which has been demonstrated to play a prominent role in ADHD pathophysiology. In a number of animal models, methylphenidate enhances locomotor activity and induces stereotypic behaviours. •Mechanism of action (Drug A): Bupropion is a norepinephrine/dopamine-reuptake inhibitor (NDRI) that exerts its pharmacological effects by weakly inhibiting the enzymes involved in the uptake of the neurotransmitters norepinephrine and dopamine from the synaptic cleft, therefore prolonging their duration of action within the neuronal synapse and the downstream effects of these neurotransmitters. More specifically, bupropion binds to the norepinephrine transporter (NET) and the dopamine transporter (DAT). Bupropion was originally classified as an "atypical" antidepressant because it does not exert the same effects as the classical antidepressants such as Monoamine Oxidase Inhibitors (MAOIs), Tricyclic Antidepressants (TCAs), or Selective Serotonin Reuptake Inhibitors (SSRIs). While it has comparable effectiveness to typical first-line options for the treatment of depression such as SSRIs, bupropion is a unique option for the treatment of MDD as it lacks any clinically relevant serotonergic effects, typical of other mood medications, or any effects on histamine or adrenaline receptors. Lack of activity at these receptors results in a more tolerable side effect profile; bupropion is less likely to cause sexual side effects, sedation, or weight gain as compared to SSRIs or TCAs, for example. When used as an aid to smoking cessation, bupropion is thought to confer its anti-craving and anti-withdrawal effects by inhibiting dopamine reuptake, which is thought to be involved in the reward pathways associated with nicotine, and through the antagonism of the nicotinic acetylcholinergic receptor (AChR), thereby blunting the effects of nicotine. Furthermore, the stimulatory effects produced by bupropion in the central nervous system are similar to nicotine's effects, making low doses of bupropion a suitable option as a nicotine substitute. When used in combination with naltrexone in the marketed product ContraveⓇ for chronic weight management, the two components are thought to have effects on areas of the brain involved in the regulation of food intake. This includes the hypothalamus, which is involved in appetite regulation, and the mesolimbic dopamine circuit, which is involved in reward pathways. Studies have shown that the combined activity of bupropion and naltrexone increase the firing rate of hypothalamic pro-opiomelanocortin (POMC) neurons and blockade of opioid receptor-mediated POMC auto-inhibition, which are associated with a reduction in food intake and increased energy expenditure. This combination was also found to reduce food intake when injected directly into the ventral tegmental area of the mesolimbic circuit in mice, which is an area associated with the regulation of reward pathways. •Mechanism of action (Drug B): While its exact mechanism is unclear, methylphenidate (MPH) has been shown to act as a norepinephrine and dopamine reuptake inhibitor (NDRI), thereby increasing the presence of these neurotransmitters in the extraneuronal space and prolonging their action. There is a dose-related effect of psychostimulants on receptor stimulation, where higher doses are shown to increase norepinephrine (NE) and dopamine (DA) efflux throughout the brain which can result in impaired cognition and locomotor-activating effects. In contrast, low doses are found to selectively activate NE and DE neurotransmission within the prefrontal cortex which is an area of the brain thought to play a prominent role in ADHD pathophysiology, thereby improving clinical efficacy and preventing side effects. The lower doses used to treat ADHD are not associated with the locomotor-activating effects associated with higher doses and instead reduce movement, impulsivity, and increase cognitive function including sustained attention and working memory. Methylphenidate's beneficial effects in sustaining attention have also been shown to be mediated by alpha-1 adrenergic receptor activity. Clinical findings have shown that children with ADHD have an abnormality in the dopamine transporter gene (DAT1), the D4 receptor gene (DRD-4), and/or the D2 receptor gene that may be at least partly overcome by the dopaminergic effects of methylphenidate, suggesting a possible mode of action. •Absorption (Drug A): Bupropion is currently available in 3 distinct, but bioequivalent formulations: immediate release (IR), sustained-release (SR), and extended-release (XL). Immediate Release Formulation In humans, following oral administration of bupropion hydrochloride tablets, peak plasma bupropion concentrations are usually achieved within 2 hours. IR formulations provide a short duration of action and are therefore generally dosed three times per day. Sustained Release Formulation In humans, following oral administration of bupropion hydrochloride sustained-release tablets (SR), peak plasma concentration (Cmax) of bupropion is usually achieved within 3 hours. SR formulations provide a 12-hour extended release of medication and are therefore generally dosed twice per day. Extended Release Formulation Following single oral administration of bupropion hydrochloride extended-release tablets (XL) to healthy volunteers, the median time to peak plasma concentrations for bupropion was approximately 5 hours. The presence of food did not affect the peak concentration or area under the curve of bupropion. XL formulations provide a 24-hour extended release of medication and are therefore generally dosed once per day/ In a trial comparing chronic dosing with bupropion hydrochloride extended-release tablets (SR) 150 mg twice daily to bupropion immediate-release formulation 100 mg 3 times daily, the steady state Cmax for bupropion after bupropion hydrochloride sustained-release tablets (SR) administration was approximately 85% of those achieved after bupropion immediate-release formulation administration. Exposure (AUC) to bupropion was equivalent for both formulations. Bioequivalence was also demonstrated for all three major active metabolites (i.e., hydroxybupropion, threohydrobupropion and erythrohydrobupropion) for both Cmax and AUC. Thus, at steady state, bupropion hydrochloride sustained-release tablets (SR) given twice daily, and the immediate-release formulation of bupropion given 3 times daily, are essentially bioequivalent for both bupropion and the 3 quantitatively important metabolites. Furthermore, in a study comparing 14-day dosing with bupropion hydrochloride extended-release tablets (XL), 300 mg once-daily to the immediate-release formulation of bupropion at 100 mg 3 times daily, equivalence was demonstrated for peak plasma concentration and area under the curve for bupropion and the three metabolites (hydroxybupropion, threohydrobupropion, and erythrohydrobupropion). Additionally, in a study comparing 14-day dosing with bupropion hydrochloride extended-release tablets (XL) 300 mg once daily to the sustained-release formulation of bupropion at 150 mg 2 times daily, equivalence was demonstrated for peak plasma concentration and area under the curve for bupropion and the three metabolites. Bupropion hydrochloride extended-release tablets (SR) can be taken with or without food. Bupropion Cmax and AUC were increased by 11% to 35% and 16% to 19%, respectively, when bupropion hydrochloride extended-release tablets (SR) was administered with food to healthy volunteers in three trials. The food effect is not considered clinically significant. Following a single-dose administration of bupropion hydrochloride extended-release tablets (SR) in humans, Cmax of bupropion's metabolite hydroxybupropion occurs approximately 6 hours post-dose and is approximately 10 times the peak level of the parent drug at steady state. The elimination half-life of hydroxybupropion is approximately 20 (±5) hours and its AUC at steady state is about 17 times that of bupropion. The times to peak concentrations for the erythrohydrobupropion and threohydrobupropion metabolites are similar to that of the hydroxybupropion metabolite. However, their elimination half-lives are longer, 33(±10) and 37 (±13) hours, respectively, and steady-state AUCs are 1.5 and 7 times that of bupropion, respectively. •Absorption (Drug B): Concerta®: Methylphenidate is readily absorbed. Following oral administration of Concerta, plasma methylhphenidate concentrations reach an initial maximum at about 1 hour followed by gradual ascending concentrations over the next 5-9 hours. Mean times to reach peak plasma concentrations across all doses of Concerta occurred between 6-10 hours. Once daily dosing minimizes the fluctuations between peak and trough concentrations associated with multiple doses of immediate-release methylphenidate treatments. Depending on the doses provided, Cmax was found to range from 6.0-15.0ng/mL, Tmax ranged from 8.1-9.4h, and AUC ranged from 50.4-121.5 ng·h/mL in children. When provided as Concerta®, methylphenidate is released through the patented Osmotic Controlled-Release Oral Delivery (OROS) system where 22% of the dose is provided as an immediate release and 78% is provided through a gradual release. OROS is comprised of an osmotically active trilayer core surrounded by a semipermeable membrane with an immediate-release drug overcoat. Within an aqueous environment, such as the stomach, the drug overcoat, which consists of 22% of the dose, dissolves within one hour, providing an initial immediate-release formulation of methylphenidate. Water then permeates through the membrane into the tablet core where the osmotically active polymer excipients expand, allowing methylphenidate to release slowly through the orifice over a period of 6-7 hours. Concerta also provides a sustained 10-12 hour effect, allowing for once-daily dosing. Biphentin®: Methylphenidate is rapidly and extensively absorbed following oral administration, with peak blood levels obtained in 1-3 hours. When provided as Biphentin®, methylphenidate is released through a multi-layer release delivery system (MLRTM) where 40% of the dose is provided as an immediate release and 60% is provided through a gradual release. Biphentin was designed to be an alternative to separate doses of immediate-release (IR) methylphenidate by providing a biphasic concentration-time profile when given as a single dose. The MLRTM release system allows for a sustained effect for 10-12 hours, allowing for once-daily dosing that covers the major times that ADHD impairment might occur (such as school, homework periods, during the workday, etc). Methylphenidate (immediate release): Methylphenidate hydrochloride is rapidly and extensively absorbed from the tablets following oral administration; however, owing to extensive first-pass metabolism, bioavailability is low (approx. 30%) and large individual differences exist (11-52%). In one study, the administration of methylphenidate hydrochloride with food accelerated absorption but had no effect on the amount absorbed. Peak plasma concentrations of 10.8 and 7.8 ng/mL were observed, on average, 2 hours after administration of 0.30 mg/kg in children and adults, respectively. Peak plasma concentrations showed marked variability between subjects. Both the area under the concentration-time curve (AUC), and the peak plasma concentrations (Cmax) showed dose-proportionality. •Volume of distribution (Drug A): No volume of distribution available •Volume of distribution (Drug B): Concerta: Plasma methylphenidate concentrations in adults decline bi-exponentially following oral administration. Biphentin: The apparent distribution volume of methylphenidate in children is approximately 20 L/kg, with substantial variability (11 to 33 L/kg). Methylphenidate (immediate release): The apparent distribution volume of methylphenidate in children was approximately 20 L/kg, with substantial variability (11-33 L/kg). The volume of distribution after an intravenous dose (Vss) is 2.23 L/kg for the racemate in healthy adult volunteers. •Protein binding (Drug A): In vitro tests show that bupropion is 84% bound to human plasma proteins at concentrations up to 200 mcg per mL. The extent of protein binding of the hydroxybupropion metabolite is similar to that for bupropion, whereas the extent of protein binding of the threohydrobupropion metabolite is about half that seen with bupropion. •Protein binding (Drug B): Concerta: In humans, 15 ± 5% of methylphenidate in the blood is bound to plasma proteins. Biphentin: In blood, methylphenidate and its metabolites are distributed between plasma (57%) and erythrocytes (43%). Methylphenidate and its metabolites exhibit low plasma protein binding (approximately 15%). Methylphenidate (immediate release): In blood, methylphenidate and its metabolites are distributed between plasma (57%) and erythrocytes (43%). Methylphenidate and its metabolites exhibit low plasma protein binding (approx. 15%). •Metabolism (Drug A): Bupropion is extensively metabolized in humans. Three metabolites are active: hydroxybupropion, which is formed via hydroxylation of the tert-butyl group of bupropion, and the amino-alcohol isomers, threohydrobupropion and erythrohydrobupropion, which are formed via reduction of the carbonyl group. In vitro findings suggest that CYP2B6 is the principal isoenzyme involved in the formation of hydroxybupropion, while cytochrome P450 enzymes are not involved in the formation of threohydrobupropion. Hydroxybupropion has been shown to have the same affinity as bupropion for the norepinephrine transporter (NET) but approximately 50% of its antidepressant activity despite reaching concentrations of ~10-fold higher than that of the parent drug. Oxidation of the bupropion side chain results in the formation of a glycine conjugate of meta-chlorobenzoic acid, which is then excreted as the major urinary metabolite. The potency and toxicity of the metabolites relative to bupropion have not been fully characterized. However, it has been demonstrated in an antidepressant screening test in mice that hydroxybupropion is one-half as potent as bupropion, while threohydrobupropion and erythrohydrobupropion are 5-fold less potent than bupropion. This may be of clinical importance because the plasma concentrations of the metabolites are as high as or higher than those of bupropion. Bupropion and its metabolites exhibit linear kinetics following chronic administration of 300 to 450 mg per day. •Metabolism (Drug B): Methylphenidate is hepatically metabolized. More specifically, it is rapidly and extensively metabolized by carboxylesterase CES1A1. Via this enzyme, methylphenidate undergoes de-esterification to ritalinic acid (a-phenyl-2-piperidine acetic acid, PPAA), which has little to no pharmacologic activity. •Route of elimination (Drug A): Bupropion is extensively metabolized in humans. Oxidation of the bupropion side chain results in the formation of a glycine conjugate of metachlorobenzoic acid, which is then excreted as the major urinary metabolite. Following oral administration of 200 mg of 14C-bupropion in humans, 87% and 10% of the radioactive dose were recovered in the urine and feces, respectively. However, the fraction of the oral dose of bupropion excreted unchanged was only 0.5%, a finding consistent with the extensive metabolism of bupropion. •Route of elimination (Drug B): After oral administration of an immediate release formulation of methylphenidate, 78%-97% of the dose is excreted in the urine and 1%-3% in the feces in the form of metabolites within 48-96 hours. Only small quantities (<1%) of unchanged methylphenidate appear in the urine. Most of the dose is excreted in the urine as ritalinic acid (60%-86%), the remainder being accounted for by minor metabolites. •Half-life (Drug A): 24 hours •Half-life (Drug B): Concerta: The half-life of methylphenidate in adults following oral administration of Concerta® was approximately 3.5 h. Biphentin: Methylphenidate is eliminated from plasma with a mean half-life of 2.4 hours in children and 2.1 hours in adults. Methylphenidate (immediate release): Methylphenidate is eliminated from the plasma with a mean half-life of 2.4 hours in children and 2.1 hours in adults. •Clearance (Drug A): No clearance available •Clearance (Drug B): The apparent mean systemic clearance after an oral dose is 10.2 and 10.5 L/h/kg in children and adults, respectively for a 0.3 mg/kg dose, and 0.565 L/h/kg after an intravenous dose of the racemate in healthy adult volunteers. •Toxicity (Drug A): Symptoms of overdose include seizures, hallucinations, loss of consciousness, tachycardia, and cardiac arrest. •Toxicity (Drug B): Symptoms of overdose include vomiting, agitation, tremors, hyperreflexia, muscle twitching, convulsions (may be followed by coma), euphoria, confusion, hallucinations, delirium, sweating, flushing, headache, hyperpyrexia, tachycardia, palpitations, cardiac arrhythmias, hypertension, mydriasis, and dryness of mucous membranes. LD 50 =190mg/kg (orally in mice) •Brand Names (Drug A): Aplenzin, Auvelity, Budeprion, Contrave, Forfivo, Wellbutrin, Zyban •Brand Names (Drug B): Aptensio, Biphentin, Concerta, Cotempla, Daytrana, Foquest, Jornay, Metadate, Methylin, Quillichew, Quillivant, Relexxii, Ritalin •Synonyms (Drug A): No synonyms listed •Synonyms (Drug B): Methyl phenidylacetate Methylphenidan Methylphenidate Methylphenidatum Metilfenidato •Summary (Drug A): Bupropion is a norepinephrine and dopamine reuptake inhibitor used in the treatment of major depressive disorder (MDD), seasonal affective disorder (SAD), and as an aid to smoking cessation. •Summary (Drug B): Methylphenidate is a stimulant used in the management of Attention Deficit Hyperactivity Disorder (ADHD). Output: Bupropion carries a dose-dependent risk of seizure1 that may be further exacerbated when combined with other medications that can reduce the seizure threshold (i.e. increase the risk of seizure), such as the affected drug. This risk may be also compounded by patient-specific factors that may increase the risk of seizure such as metabolic disorders and illicit drug use. The severity of the interaction is moderate.

Does Bupropion and Methyltestosterone interact?

•Drug A: Bupropion •Drug B: Methyltestosterone •Severity: MODERATE •Description: The metabolism of Methyltestosterone can be decreased when combined with Bupropion. •Extended Description: When a CYP2B6 substrate is coadministered with another CYP2B6 substrate, both substrates will invariably compete with each other to be metabolized by the limited quantities of CYP2B6 isoenzymes present in the body. When one substrate is subsequently capable of 'out-competing' the other, this other substrate will have its CYP2B6 facilitated metabolism stalled or otherwise decreased for a time, resulting in increased serum concentrations of this substrate and/or an increased risk, incidence, or severity of adverse effects associated with exposure to this substrate. •Indication (Drug A): Bupropion is indicated for the treatment of major depressive disorder (MDD), seasonal affective disorder (SAD), and as an aid to smoking cessation. When used in combination with naltrexone as the marketed product ContraveⓇ, bupropion is indicated as an adjunct to a reduced-calorie diet and increased physical activity for chronic weight management in adults with an initial body mass index (BMI) of: 30 kg/m^2 or greater (obese) or 27 kg/m^2 or greater (overweight) in the presence of at least one weight-related comorbid condition (e.g., hypertension, type 2 diabetes mellitus, or dyslipidemia). Bupropion is also used off-label as a first-line treatment in patients with ADHD and comorbid bipolar disorder when used as an adjunct to mood stabilizers. •Indication (Drug B): Methyltestosterone is an anabolic steroid hormone used to treat men with a testosterone deficiency. It is also used in women to treat breast cancer, breast pain, swelling due to pregnancy, and with the addition of estrogen it can treat symptoms of menopause. •Pharmacodynamics (Drug A): Bupropion is chemically unrelated to tricyclic, tetracyclic, selective serotonin re-uptake inhibitors, or other known antidepressant agents. Compared to classical tricyclic antidepressants, Bupropion is a relatively weak inhibitor of the neuronal uptake of norepinephrine and dopamine. In addition, Bupropion does not inhibit monoamine oxidase. Bupropion has been found to be essentially inactive at the serotonin transporter (SERT)(IC50 >10 000 nM), however both bupropion and its primary metabolite hydroxybupropion have been found to block the function of cation-selective serotonin type 3A receptors (5-HT3ARs). Bupropion produces dose-related central nervous system (CNS) stimulant effects in animals, as evidenced by increased locomotor activity, increased rates of responding in various schedule-controlled operant behaviour tasks, and, at high doses, induction of mild stereotyped behaviour. Due to these stimulant effects and selective activity at dopamine and norepinephrine receptors, bupropion has been identified as having an abuse potential. Bupropion has a similar structure to the controlled substance Cathinone, and has been identified as having mild amphetamine-like activity, particularly when inhaled or injected. Bupropion is also known to lower the seizure threshold, making any pre-existing seizure conditions a contraindication to its use. This risk is exacerbated when bupropion is combined with other drugs or substances that lower the seizure threshold, such as cocaine, or in clinical situations that would increase the risk of a seizure such as abrupt alcohol or benzodiazepine withdrawal. As norepinephrine has been shown to have anticonvulsant properties, bupropion's inhibitory effects on NET are thought to contribute to its pro-convulsant activity. Bupropion has been shown to increase blood pressure and pose a risk for exacerbation of unmanaged or pre-existing hypertension, however, clinical trials of bupropion in smokers with CVD have not identified an increased incidence of CV events including stroke or heart attack. In clinical trials, the mean increase in systolic blood pressure associated with the use of bupropion was found to be 1.3 mmHg. •Pharmacodynamics (Drug B): Testosterone is a steroid hormone from the androgen group. Testosterone is primarily secreted from the testes of males. In females, it is produced in the ovaries, adrenal glands and by conversion of adrostenedione in the periphery. It is the principal male sex hormone and an anabolic steroid. In both males and females, it plays key roles in health and well-being. Examples include enhanced libido, energy, immune function, and protection against osteoporosis. On average, the adult male body produces about twenty times the amount of testosterone than an adult female's body does. •Mechanism of action (Drug A): Bupropion is a norepinephrine/dopamine-reuptake inhibitor (NDRI) that exerts its pharmacological effects by weakly inhibiting the enzymes involved in the uptake of the neurotransmitters norepinephrine and dopamine from the synaptic cleft, therefore prolonging their duration of action within the neuronal synapse and the downstream effects of these neurotransmitters. More specifically, bupropion binds to the norepinephrine transporter (NET) and the dopamine transporter (DAT). Bupropion was originally classified as an "atypical" antidepressant because it does not exert the same effects as the classical antidepressants such as Monoamine Oxidase Inhibitors (MAOIs), Tricyclic Antidepressants (TCAs), or Selective Serotonin Reuptake Inhibitors (SSRIs). While it has comparable effectiveness to typical first-line options for the treatment of depression such as SSRIs, bupropion is a unique option for the treatment of MDD as it lacks any clinically relevant serotonergic effects, typical of other mood medications, or any effects on histamine or adrenaline receptors. Lack of activity at these receptors results in a more tolerable side effect profile; bupropion is less likely to cause sexual side effects, sedation, or weight gain as compared to SSRIs or TCAs, for example. When used as an aid to smoking cessation, bupropion is thought to confer its anti-craving and anti-withdrawal effects by inhibiting dopamine reuptake, which is thought to be involved in the reward pathways associated with nicotine, and through the antagonism of the nicotinic acetylcholinergic receptor (AChR), thereby blunting the effects of nicotine. Furthermore, the stimulatory effects produced by bupropion in the central nervous system are similar to nicotine's effects, making low doses of bupropion a suitable option as a nicotine substitute. When used in combination with naltrexone in the marketed product ContraveⓇ for chronic weight management, the two components are thought to have effects on areas of the brain involved in the regulation of food intake. This includes the hypothalamus, which is involved in appetite regulation, and the mesolimbic dopamine circuit, which is involved in reward pathways. Studies have shown that the combined activity of bupropion and naltrexone increase the firing rate of hypothalamic pro-opiomelanocortin (POMC) neurons and blockade of opioid receptor-mediated POMC auto-inhibition, which are associated with a reduction in food intake and increased energy expenditure. This combination was also found to reduce food intake when injected directly into the ventral tegmental area of the mesolimbic circuit in mice, which is an area associated with the regulation of reward pathways. •Mechanism of action (Drug B): The effects of testosterone in humans and other vertebrates occur by way of two main mechanisms: by activation of the androgen receptor (directly or as DHT), and by conversion to estradiol and activation of certain estrogen receptors. Free testosterone (T) is transported into the cytoplasm of target tissue cells, where it can bind to the androgen receptor, or can be reduced to 5α-dihydrotestosterone (DHT) by the cytoplasmic enzyme 5α-reductase. DHT binds to the same androgen receptor even more strongly than T, so that its androgenic potency is about 2.5 times that of T. The T-receptor or DHT-receptor complex undergoes a structural change that allows it to move into the cell nucleus and bind directly to specific nucleotide sequences of the chromosomal DNA. The areas of binding are called hormone response elements (HREs), and influence transcriptional activity of certain genes, producing the androgen effects. •Absorption (Drug A): Bupropion is currently available in 3 distinct, but bioequivalent formulations: immediate release (IR), sustained-release (SR), and extended-release (XL). Immediate Release Formulation In humans, following oral administration of bupropion hydrochloride tablets, peak plasma bupropion concentrations are usually achieved within 2 hours. IR formulations provide a short duration of action and are therefore generally dosed three times per day. Sustained Release Formulation In humans, following oral administration of bupropion hydrochloride sustained-release tablets (SR), peak plasma concentration (Cmax) of bupropion is usually achieved within 3 hours. SR formulations provide a 12-hour extended release of medication and are therefore generally dosed twice per day. Extended Release Formulation Following single oral administration of bupropion hydrochloride extended-release tablets (XL) to healthy volunteers, the median time to peak plasma concentrations for bupropion was approximately 5 hours. The presence of food did not affect the peak concentration or area under the curve of bupropion. XL formulations provide a 24-hour extended release of medication and are therefore generally dosed once per day/ In a trial comparing chronic dosing with bupropion hydrochloride extended-release tablets (SR) 150 mg twice daily to bupropion immediate-release formulation 100 mg 3 times daily, the steady state Cmax for bupropion after bupropion hydrochloride sustained-release tablets (SR) administration was approximately 85% of those achieved after bupropion immediate-release formulation administration. Exposure (AUC) to bupropion was equivalent for both formulations. Bioequivalence was also demonstrated for all three major active metabolites (i.e., hydroxybupropion, threohydrobupropion and erythrohydrobupropion) for both Cmax and AUC. Thus, at steady state, bupropion hydrochloride sustained-release tablets (SR) given twice daily, and the immediate-release formulation of bupropion given 3 times daily, are essentially bioequivalent for both bupropion and the 3 quantitatively important metabolites. Furthermore, in a study comparing 14-day dosing with bupropion hydrochloride extended-release tablets (XL), 300 mg once-daily to the immediate-release formulation of bupropion at 100 mg 3 times daily, equivalence was demonstrated for peak plasma concentration and area under the curve for bupropion and the three metabolites (hydroxybupropion, threohydrobupropion, and erythrohydrobupropion). Additionally, in a study comparing 14-day dosing with bupropion hydrochloride extended-release tablets (XL) 300 mg once daily to the sustained-release formulation of bupropion at 150 mg 2 times daily, equivalence was demonstrated for peak plasma concentration and area under the curve for bupropion and the three metabolites. Bupropion hydrochloride extended-release tablets (SR) can be taken with or without food. Bupropion Cmax and AUC were increased by 11% to 35% and 16% to 19%, respectively, when bupropion hydrochloride extended-release tablets (SR) was administered with food to healthy volunteers in three trials. The food effect is not considered clinically significant. Following a single-dose administration of bupropion hydrochloride extended-release tablets (SR) in humans, Cmax of bupropion's metabolite hydroxybupropion occurs approximately 6 hours post-dose and is approximately 10 times the peak level of the parent drug at steady state. The elimination half-life of hydroxybupropion is approximately 20 (±5) hours and its AUC at steady state is about 17 times that of bupropion. The times to peak concentrations for the erythrohydrobupropion and threohydrobupropion metabolites are similar to that of the hydroxybupropion metabolite. However, their elimination half-lives are longer, 33(±10) and 37 (±13) hours, respectively, and steady-state AUCs are 1.5 and 7 times that of bupropion, respectively. •Absorption (Drug B): The methyl group aids to increase oral bioavailability. •Volume of distribution (Drug A): No volume of distribution available •Volume of distribution (Drug B): No volume of distribution available •Protein binding (Drug A): In vitro tests show that bupropion is 84% bound to human plasma proteins at concentrations up to 200 mcg per mL. The extent of protein binding of the hydroxybupropion metabolite is similar to that for bupropion, whereas the extent of protein binding of the threohydrobupropion metabolite is about half that seen with bupropion. •Protein binding (Drug B): 40% of testosterone in plasma is bound to sex hormone-binding globulin and 2% remains unbound and the rest is bound to albumin and other proteins. •Metabolism (Drug A): Bupropion is extensively metabolized in humans. Three metabolites are active: hydroxybupropion, which is formed via hydroxylation of the tert-butyl group of bupropion, and the amino-alcohol isomers, threohydrobupropion and erythrohydrobupropion, which are formed via reduction of the carbonyl group. In vitro findings suggest that CYP2B6 is the principal isoenzyme involved in the formation of hydroxybupropion, while cytochrome P450 enzymes are not involved in the formation of threohydrobupropion. Hydroxybupropion has been shown to have the same affinity as bupropion for the norepinephrine transporter (NET) but approximately 50% of its antidepressant activity despite reaching concentrations of ~10-fold higher than that of the parent drug. Oxidation of the bupropion side chain results in the formation of a glycine conjugate of meta-chlorobenzoic acid, which is then excreted as the major urinary metabolite. The potency and toxicity of the metabolites relative to bupropion have not been fully characterized. However, it has been demonstrated in an antidepressant screening test in mice that hydroxybupropion is one-half as potent as bupropion, while threohydrobupropion and erythrohydrobupropion are 5-fold less potent than bupropion. This may be of clinical importance because the plasma concentrations of the metabolites are as high as or higher than those of bupropion. Bupropion and its metabolites exhibit linear kinetics following chronic administration of 300 to 450 mg per day. •Metabolism (Drug B): Hepatic. Testosterone is metabolized to 17-keto steroids through two different pathways. The major active metabolites are estradiol and dihydrotestosterone (DHT). •Route of elimination (Drug A): Bupropion is extensively metabolized in humans. Oxidation of the bupropion side chain results in the formation of a glycine conjugate of metachlorobenzoic acid, which is then excreted as the major urinary metabolite. Following oral administration of 200 mg of 14C-bupropion in humans, 87% and 10% of the radioactive dose were recovered in the urine and feces, respectively. However, the fraction of the oral dose of bupropion excreted unchanged was only 0.5%, a finding consistent with the extensive metabolism of bupropion. •Route of elimination (Drug B): 90% urine / 10% feces •Half-life (Drug A): 24 hours •Half-life (Drug B): 6-8 hours •Clearance (Drug A): No clearance available •Clearance (Drug B): No clearance available •Toxicity (Drug A): Symptoms of overdose include seizures, hallucinations, loss of consciousness, tachycardia, and cardiac arrest. •Toxicity (Drug B): Side effects include amnesia, anxiety, discolored hair, dizziness, dry skin, hirsutism, hostility, impaired urination, paresthesia, penis disorder, peripheral edema, sweating, and vasodilation. •Brand Names (Drug A): Aplenzin, Auvelity, Budeprion, Contrave, Forfivo, Wellbutrin, Zyban •Brand Names (Drug B): Covaryx, Methitest •Synonyms (Drug A): No synonyms listed •Synonyms (Drug B): 17-methyltestosterone Methyltestosterone Methyltestosteronum Metiltestosterona •Summary (Drug A): Bupropion is a norepinephrine and dopamine reuptake inhibitor used in the treatment of major depressive disorder (MDD), seasonal affective disorder (SAD), and as an aid to smoking cessation. •Summary (Drug B): Methyltestosterone is a synthetic anabolic steroid used for the replacement therapy in conditions associated with testosterone deficiencies in males, such as hypogonadism, and treatment of advancing inoperable metastatic breast cancer in females.

When a CYP2B6 substrate is coadministered with another CYP2B6 substrate, both substrates will invariably compete with each other to be metabolized by the limited quantities of CYP2B6 isoenzymes present in the body. When one substrate is subsequently capable of 'out-competing' the other, this other substrate will have its CYP2B6 facilitated metabolism stalled or otherwise decreased for a time, resulting in increased serum concentrations of this substrate and/or an increased risk, incidence, or severity of adverse effects associated with exposure to this substrate. The severity of the interaction is moderate.

Question: Does Bupropion and Methyltestosterone interact? Information: •Drug A: Bupropion •Drug B: Methyltestosterone •Severity: MODERATE •Description: The metabolism of Methyltestosterone can be decreased when combined with Bupropion. •Extended Description: When a CYP2B6 substrate is coadministered with another CYP2B6 substrate, both substrates will invariably compete with each other to be metabolized by the limited quantities of CYP2B6 isoenzymes present in the body. When one substrate is subsequently capable of 'out-competing' the other, this other substrate will have its CYP2B6 facilitated metabolism stalled or otherwise decreased for a time, resulting in increased serum concentrations of this substrate and/or an increased risk, incidence, or severity of adverse effects associated with exposure to this substrate. •Indication (Drug A): Bupropion is indicated for the treatment of major depressive disorder (MDD), seasonal affective disorder (SAD), and as an aid to smoking cessation. When used in combination with naltrexone as the marketed product ContraveⓇ, bupropion is indicated as an adjunct to a reduced-calorie diet and increased physical activity for chronic weight management in adults with an initial body mass index (BMI) of: 30 kg/m^2 or greater (obese) or 27 kg/m^2 or greater (overweight) in the presence of at least one weight-related comorbid condition (e.g., hypertension, type 2 diabetes mellitus, or dyslipidemia). Bupropion is also used off-label as a first-line treatment in patients with ADHD and comorbid bipolar disorder when used as an adjunct to mood stabilizers. •Indication (Drug B): Methyltestosterone is an anabolic steroid hormone used to treat men with a testosterone deficiency. It is also used in women to treat breast cancer, breast pain, swelling due to pregnancy, and with the addition of estrogen it can treat symptoms of menopause. •Pharmacodynamics (Drug A): Bupropion is chemically unrelated to tricyclic, tetracyclic, selective serotonin re-uptake inhibitors, or other known antidepressant agents. Compared to classical tricyclic antidepressants, Bupropion is a relatively weak inhibitor of the neuronal uptake of norepinephrine and dopamine. In addition, Bupropion does not inhibit monoamine oxidase. Bupropion has been found to be essentially inactive at the serotonin transporter (SERT)(IC50 >10 000 nM), however both bupropion and its primary metabolite hydroxybupropion have been found to block the function of cation-selective serotonin type 3A receptors (5-HT3ARs). Bupropion produces dose-related central nervous system (CNS) stimulant effects in animals, as evidenced by increased locomotor activity, increased rates of responding in various schedule-controlled operant behaviour tasks, and, at high doses, induction of mild stereotyped behaviour. Due to these stimulant effects and selective activity at dopamine and norepinephrine receptors, bupropion has been identified as having an abuse potential. Bupropion has a similar structure to the controlled substance Cathinone, and has been identified as having mild amphetamine-like activity, particularly when inhaled or injected. Bupropion is also known to lower the seizure threshold, making any pre-existing seizure conditions a contraindication to its use. This risk is exacerbated when bupropion is combined with other drugs or substances that lower the seizure threshold, such as cocaine, or in clinical situations that would increase the risk of a seizure such as abrupt alcohol or benzodiazepine withdrawal. As norepinephrine has been shown to have anticonvulsant properties, bupropion's inhibitory effects on NET are thought to contribute to its pro-convulsant activity. Bupropion has been shown to increase blood pressure and pose a risk for exacerbation of unmanaged or pre-existing hypertension, however, clinical trials of bupropion in smokers with CVD have not identified an increased incidence of CV events including stroke or heart attack. In clinical trials, the mean increase in systolic blood pressure associated with the use of bupropion was found to be 1.3 mmHg. •Pharmacodynamics (Drug B): Testosterone is a steroid hormone from the androgen group. Testosterone is primarily secreted from the testes of males. In females, it is produced in the ovaries, adrenal glands and by conversion of adrostenedione in the periphery. It is the principal male sex hormone and an anabolic steroid. In both males and females, it plays key roles in health and well-being. Examples include enhanced libido, energy, immune function, and protection against osteoporosis. On average, the adult male body produces about twenty times the amount of testosterone than an adult female's body does. •Mechanism of action (Drug A): Bupropion is a norepinephrine/dopamine-reuptake inhibitor (NDRI) that exerts its pharmacological effects by weakly inhibiting the enzymes involved in the uptake of the neurotransmitters norepinephrine and dopamine from the synaptic cleft, therefore prolonging their duration of action within the neuronal synapse and the downstream effects of these neurotransmitters. More specifically, bupropion binds to the norepinephrine transporter (NET) and the dopamine transporter (DAT). Bupropion was originally classified as an "atypical" antidepressant because it does not exert the same effects as the classical antidepressants such as Monoamine Oxidase Inhibitors (MAOIs), Tricyclic Antidepressants (TCAs), or Selective Serotonin Reuptake Inhibitors (SSRIs). While it has comparable effectiveness to typical first-line options for the treatment of depression such as SSRIs, bupropion is a unique option for the treatment of MDD as it lacks any clinically relevant serotonergic effects, typical of other mood medications, or any effects on histamine or adrenaline receptors. Lack of activity at these receptors results in a more tolerable side effect profile; bupropion is less likely to cause sexual side effects, sedation, or weight gain as compared to SSRIs or TCAs, for example. When used as an aid to smoking cessation, bupropion is thought to confer its anti-craving and anti-withdrawal effects by inhibiting dopamine reuptake, which is thought to be involved in the reward pathways associated with nicotine, and through the antagonism of the nicotinic acetylcholinergic receptor (AChR), thereby blunting the effects of nicotine. Furthermore, the stimulatory effects produced by bupropion in the central nervous system are similar to nicotine's effects, making low doses of bupropion a suitable option as a nicotine substitute. When used in combination with naltrexone in the marketed product ContraveⓇ for chronic weight management, the two components are thought to have effects on areas of the brain involved in the regulation of food intake. This includes the hypothalamus, which is involved in appetite regulation, and the mesolimbic dopamine circuit, which is involved in reward pathways. Studies have shown that the combined activity of bupropion and naltrexone increase the firing rate of hypothalamic pro-opiomelanocortin (POMC) neurons and blockade of opioid receptor-mediated POMC auto-inhibition, which are associated with a reduction in food intake and increased energy expenditure. This combination was also found to reduce food intake when injected directly into the ventral tegmental area of the mesolimbic circuit in mice, which is an area associated with the regulation of reward pathways. •Mechanism of action (Drug B): The effects of testosterone in humans and other vertebrates occur by way of two main mechanisms: by activation of the androgen receptor (directly or as DHT), and by conversion to estradiol and activation of certain estrogen receptors. Free testosterone (T) is transported into the cytoplasm of target tissue cells, where it can bind to the androgen receptor, or can be reduced to 5α-dihydrotestosterone (DHT) by the cytoplasmic enzyme 5α-reductase. DHT binds to the same androgen receptor even more strongly than T, so that its androgenic potency is about 2.5 times that of T. The T-receptor or DHT-receptor complex undergoes a structural change that allows it to move into the cell nucleus and bind directly to specific nucleotide sequences of the chromosomal DNA. The areas of binding are called hormone response elements (HREs), and influence transcriptional activity of certain genes, producing the androgen effects. •Absorption (Drug A): Bupropion is currently available in 3 distinct, but bioequivalent formulations: immediate release (IR), sustained-release (SR), and extended-release (XL). Immediate Release Formulation In humans, following oral administration of bupropion hydrochloride tablets, peak plasma bupropion concentrations are usually achieved within 2 hours. IR formulations provide a short duration of action and are therefore generally dosed three times per day. Sustained Release Formulation In humans, following oral administration of bupropion hydrochloride sustained-release tablets (SR), peak plasma concentration (Cmax) of bupropion is usually achieved within 3 hours. SR formulations provide a 12-hour extended release of medication and are therefore generally dosed twice per day. Extended Release Formulation Following single oral administration of bupropion hydrochloride extended-release tablets (XL) to healthy volunteers, the median time to peak plasma concentrations for bupropion was approximately 5 hours. The presence of food did not affect the peak concentration or area under the curve of bupropion. XL formulations provide a 24-hour extended release of medication and are therefore generally dosed once per day/ In a trial comparing chronic dosing with bupropion hydrochloride extended-release tablets (SR) 150 mg twice daily to bupropion immediate-release formulation 100 mg 3 times daily, the steady state Cmax for bupropion after bupropion hydrochloride sustained-release tablets (SR) administration was approximately 85% of those achieved after bupropion immediate-release formulation administration. Exposure (AUC) to bupropion was equivalent for both formulations. Bioequivalence was also demonstrated for all three major active metabolites (i.e., hydroxybupropion, threohydrobupropion and erythrohydrobupropion) for both Cmax and AUC. Thus, at steady state, bupropion hydrochloride sustained-release tablets (SR) given twice daily, and the immediate-release formulation of bupropion given 3 times daily, are essentially bioequivalent for both bupropion and the 3 quantitatively important metabolites. Furthermore, in a study comparing 14-day dosing with bupropion hydrochloride extended-release tablets (XL), 300 mg once-daily to the immediate-release formulation of bupropion at 100 mg 3 times daily, equivalence was demonstrated for peak plasma concentration and area under the curve for bupropion and the three metabolites (hydroxybupropion, threohydrobupropion, and erythrohydrobupropion). Additionally, in a study comparing 14-day dosing with bupropion hydrochloride extended-release tablets (XL) 300 mg once daily to the sustained-release formulation of bupropion at 150 mg 2 times daily, equivalence was demonstrated for peak plasma concentration and area under the curve for bupropion and the three metabolites. Bupropion hydrochloride extended-release tablets (SR) can be taken with or without food. Bupropion Cmax and AUC were increased by 11% to 35% and 16% to 19%, respectively, when bupropion hydrochloride extended-release tablets (SR) was administered with food to healthy volunteers in three trials. The food effect is not considered clinically significant. Following a single-dose administration of bupropion hydrochloride extended-release tablets (SR) in humans, Cmax of bupropion's metabolite hydroxybupropion occurs approximately 6 hours post-dose and is approximately 10 times the peak level of the parent drug at steady state. The elimination half-life of hydroxybupropion is approximately 20 (±5) hours and its AUC at steady state is about 17 times that of bupropion. The times to peak concentrations for the erythrohydrobupropion and threohydrobupropion metabolites are similar to that of the hydroxybupropion metabolite. However, their elimination half-lives are longer, 33(±10) and 37 (±13) hours, respectively, and steady-state AUCs are 1.5 and 7 times that of bupropion, respectively. •Absorption (Drug B): The methyl group aids to increase oral bioavailability. •Volume of distribution (Drug A): No volume of distribution available •Volume of distribution (Drug B): No volume of distribution available •Protein binding (Drug A): In vitro tests show that bupropion is 84% bound to human plasma proteins at concentrations up to 200 mcg per mL. The extent of protein binding of the hydroxybupropion metabolite is similar to that for bupropion, whereas the extent of protein binding of the threohydrobupropion metabolite is about half that seen with bupropion. •Protein binding (Drug B): 40% of testosterone in plasma is bound to sex hormone-binding globulin and 2% remains unbound and the rest is bound to albumin and other proteins. •Metabolism (Drug A): Bupropion is extensively metabolized in humans. Three metabolites are active: hydroxybupropion, which is formed via hydroxylation of the tert-butyl group of bupropion, and the amino-alcohol isomers, threohydrobupropion and erythrohydrobupropion, which are formed via reduction of the carbonyl group. In vitro findings suggest that CYP2B6 is the principal isoenzyme involved in the formation of hydroxybupropion, while cytochrome P450 enzymes are not involved in the formation of threohydrobupropion. Hydroxybupropion has been shown to have the same affinity as bupropion for the norepinephrine transporter (NET) but approximately 50% of its antidepressant activity despite reaching concentrations of ~10-fold higher than that of the parent drug. Oxidation of the bupropion side chain results in the formation of a glycine conjugate of meta-chlorobenzoic acid, which is then excreted as the major urinary metabolite. The potency and toxicity of the metabolites relative to bupropion have not been fully characterized. However, it has been demonstrated in an antidepressant screening test in mice that hydroxybupropion is one-half as potent as bupropion, while threohydrobupropion and erythrohydrobupropion are 5-fold less potent than bupropion. This may be of clinical importance because the plasma concentrations of the metabolites are as high as or higher than those of bupropion. Bupropion and its metabolites exhibit linear kinetics following chronic administration of 300 to 450 mg per day. •Metabolism (Drug B): Hepatic. Testosterone is metabolized to 17-keto steroids through two different pathways. The major active metabolites are estradiol and dihydrotestosterone (DHT). •Route of elimination (Drug A): Bupropion is extensively metabolized in humans. Oxidation of the bupropion side chain results in the formation of a glycine conjugate of metachlorobenzoic acid, which is then excreted as the major urinary metabolite. Following oral administration of 200 mg of 14C-bupropion in humans, 87% and 10% of the radioactive dose were recovered in the urine and feces, respectively. However, the fraction of the oral dose of bupropion excreted unchanged was only 0.5%, a finding consistent with the extensive metabolism of bupropion. •Route of elimination (Drug B): 90% urine / 10% feces •Half-life (Drug A): 24 hours •Half-life (Drug B): 6-8 hours •Clearance (Drug A): No clearance available •Clearance (Drug B): No clearance available •Toxicity (Drug A): Symptoms of overdose include seizures, hallucinations, loss of consciousness, tachycardia, and cardiac arrest. •Toxicity (Drug B): Side effects include amnesia, anxiety, discolored hair, dizziness, dry skin, hirsutism, hostility, impaired urination, paresthesia, penis disorder, peripheral edema, sweating, and vasodilation. •Brand Names (Drug A): Aplenzin, Auvelity, Budeprion, Contrave, Forfivo, Wellbutrin, Zyban •Brand Names (Drug B): Covaryx, Methitest •Synonyms (Drug A): No synonyms listed •Synonyms (Drug B): 17-methyltestosterone Methyltestosterone Methyltestosteronum Metiltestosterona •Summary (Drug A): Bupropion is a norepinephrine and dopamine reuptake inhibitor used in the treatment of major depressive disorder (MDD), seasonal affective disorder (SAD), and as an aid to smoking cessation. •Summary (Drug B): Methyltestosterone is a synthetic anabolic steroid used for the replacement therapy in conditions associated with testosterone deficiencies in males, such as hypogonadism, and treatment of advancing inoperable metastatic breast cancer in females. Output: When a CYP2B6 substrate is coadministered with another CYP2B6 substrate, both substrates will invariably compete with each other to be metabolized by the limited quantities of CYP2B6 isoenzymes present in the body. When one substrate is subsequently capable of 'out-competing' the other, this other substrate will have its CYP2B6 facilitated metabolism stalled or otherwise decreased for a time, resulting in increased serum concentrations of this substrate and/or an increased risk, incidence, or severity of adverse effects associated with exposure to this substrate. The severity of the interaction is moderate.

Does Bupropion and Metoclopramide interact?

•Drug A: Bupropion •Drug B: Metoclopramide •Severity: MODERATE •Description: The risk or severity of sedation can be increased when Metoclopramide is combined with Bupropion. •Extended Description: When coadministered with central nervous system depressants, metoclopramide may cause enhanced sedation due to additive effects. Both drugs have the propensity to cause sedation, leading to significant effects when administered concomitantly. •Indication (Drug A): Bupropion is indicated for the treatment of major depressive disorder (MDD), seasonal affective disorder (SAD), and as an aid to smoking cessation. When used in combination with naltrexone as the marketed product ContraveⓇ, bupropion is indicated as an adjunct to a reduced-calorie diet and increased physical activity for chronic weight management in adults with an initial body mass index (BMI) of: 30 kg/m^2 or greater (obese) or 27 kg/m^2 or greater (overweight) in the presence of at least one weight-related comorbid condition (e.g., hypertension, type 2 diabetes mellitus, or dyslipidemia). Bupropion is also used off-label as a first-line treatment in patients with ADHD and comorbid bipolar disorder when used as an adjunct to mood stabilizers. •Indication (Drug B): Metoclopramide in the oral tablet form is used for symptomatic treatment of both acute and recurrent diabetic gastroparesis, in addition to the treatment of gastroesophageal reflux disease (GERD) in patients who have failed to respond to traditional therapy. A nasal spray formulation is also indicated to treat adults with acute, recurrent diabetic gastroparesis. In the intravenous injection form, it is indicated for the above conditions as well as for the prevention of vomiting that may follow emetogenic chemotherapy or nausea and vomiting after surgery. Intravenous metoclopramide facilitates intubation of the small bowel and stimulates gastric emptying and barium flow in patients who require radiological examination of the stomach or small intestine. In some cases, the delay of gastrointestinal emptying interferes with the radiographic visualization of the gastrointestinal tract, and metoclopramide is used to facilitate emptying in these cases, allowing for adequate diagnostic visualization. Some off-label uses of metoclopramide include the management of radiation-induced nausea and vomiting, gastric bezoars, intractable hiccups, and migraine pain. •Pharmacodynamics (Drug A): Bupropion is chemically unrelated to tricyclic, tetracyclic, selective serotonin re-uptake inhibitors, or other known antidepressant agents. Compared to classical tricyclic antidepressants, Bupropion is a relatively weak inhibitor of the neuronal uptake of norepinephrine and dopamine. In addition, Bupropion does not inhibit monoamine oxidase. Bupropion has been found to be essentially inactive at the serotonin transporter (SERT)(IC50 >10 000 nM), however both bupropion and its primary metabolite hydroxybupropion have been found to block the function of cation-selective serotonin type 3A receptors (5-HT3ARs). Bupropion produces dose-related central nervous system (CNS) stimulant effects in animals, as evidenced by increased locomotor activity, increased rates of responding in various schedule-controlled operant behaviour tasks, and, at high doses, induction of mild stereotyped behaviour. Due to these stimulant effects and selective activity at dopamine and norepinephrine receptors, bupropion has been identified as having an abuse potential. Bupropion has a similar structure to the controlled substance Cathinone, and has been identified as having mild amphetamine-like activity, particularly when inhaled or injected. Bupropion is also known to lower the seizure threshold, making any pre-existing seizure conditions a contraindication to its use. This risk is exacerbated when bupropion is combined with other drugs or substances that lower the seizure threshold, such as cocaine, or in clinical situations that would increase the risk of a seizure such as abrupt alcohol or benzodiazepine withdrawal. As norepinephrine has been shown to have anticonvulsant properties, bupropion's inhibitory effects on NET are thought to contribute to its pro-convulsant activity. Bupropion has been shown to increase blood pressure and pose a risk for exacerbation of unmanaged or pre-existing hypertension, however, clinical trials of bupropion in smokers with CVD have not identified an increased incidence of CV events including stroke or heart attack. In clinical trials, the mean increase in systolic blood pressure associated with the use of bupropion was found to be 1.3 mmHg. •Pharmacodynamics (Drug B): Metoclopramide increases gastric emptying by decreasing lower esophageal sphincter (LES) pressure. It also exerts effects on the area postrema of the brain, preventing and relieving the symptoms of nausea and vomiting. In addition, this drug increases gastrointestinal motility without increasing biliary, gastric, or pancreatic secretions. Because of its antidopaminergic activity, metoclopramide can cause symptoms of tardive dyskinesia (TD), dystonia, and akathisia, and should therefore not be administered for longer than 12 weeks. •Mechanism of action (Drug A): Bupropion is a norepinephrine/dopamine-reuptake inhibitor (NDRI) that exerts its pharmacological effects by weakly inhibiting the enzymes involved in the uptake of the neurotransmitters norepinephrine and dopamine from the synaptic cleft, therefore prolonging their duration of action within the neuronal synapse and the downstream effects of these neurotransmitters. More specifically, bupropion binds to the norepinephrine transporter (NET) and the dopamine transporter (DAT). Bupropion was originally classified as an "atypical" antidepressant because it does not exert the same effects as the classical antidepressants such as Monoamine Oxidase Inhibitors (MAOIs), Tricyclic Antidepressants (TCAs), or Selective Serotonin Reuptake Inhibitors (SSRIs). While it has comparable effectiveness to typical first-line options for the treatment of depression such as SSRIs, bupropion is a unique option for the treatment of MDD as it lacks any clinically relevant serotonergic effects, typical of other mood medications, or any effects on histamine or adrenaline receptors. Lack of activity at these receptors results in a more tolerable side effect profile; bupropion is less likely to cause sexual side effects, sedation, or weight gain as compared to SSRIs or TCAs, for example. When used as an aid to smoking cessation, bupropion is thought to confer its anti-craving and anti-withdrawal effects by inhibiting dopamine reuptake, which is thought to be involved in the reward pathways associated with nicotine, and through the antagonism of the nicotinic acetylcholinergic receptor (AChR), thereby blunting the effects of nicotine. Furthermore, the stimulatory effects produced by bupropion in the central nervous system are similar to nicotine's effects, making low doses of bupropion a suitable option as a nicotine substitute. When used in combination with naltrexone in the marketed product ContraveⓇ for chronic weight management, the two components are thought to have effects on areas of the brain involved in the regulation of food intake. This includes the hypothalamus, which is involved in appetite regulation, and the mesolimbic dopamine circuit, which is involved in reward pathways. Studies have shown that the combined activity of bupropion and naltrexone increase the firing rate of hypothalamic pro-opiomelanocortin (POMC) neurons and blockade of opioid receptor-mediated POMC auto-inhibition, which are associated with a reduction in food intake and increased energy expenditure. This combination was also found to reduce food intake when injected directly into the ventral tegmental area of the mesolimbic circuit in mice, which is an area associated with the regulation of reward pathways. •Mechanism of action (Drug B): Metoclopramide causes antiemetic effects by inhibiting dopamine D2 and serotonin 5-HT3 receptors in the chemoreceptor trigger zone (CTZ) located in the area postrema of the brain. Administration of this drug leads to prokinetic effects via inhibitory actions on presynaptic and postsynaptic D2 receptors, agonism of serotonin 5-HT4 receptors, and antagonism of muscarinic receptor inhibition. This action enhances the release of acetylcholine, causing increased lower esophageal sphincter (LES) and gastric tone, accelerating gastric emptying and transit through the gut. Metoclopramide antagonizes the dopamine D2 receptors. Dopamine exerts relaxant effect on the gastrointestinal tract through binding to muscular D2 receptors. •Absorption (Drug A): Bupropion is currently available in 3 distinct, but bioequivalent formulations: immediate release (IR), sustained-release (SR), and extended-release (XL). Immediate Release Formulation In humans, following oral administration of bupropion hydrochloride tablets, peak plasma bupropion concentrations are usually achieved within 2 hours. IR formulations provide a short duration of action and are therefore generally dosed three times per day. Sustained Release Formulation In humans, following oral administration of bupropion hydrochloride sustained-release tablets (SR), peak plasma concentration (Cmax) of bupropion is usually achieved within 3 hours. SR formulations provide a 12-hour extended release of medication and are therefore generally dosed twice per day. Extended Release Formulation Following single oral administration of bupropion hydrochloride extended-release tablets (XL) to healthy volunteers, the median time to peak plasma concentrations for bupropion was approximately 5 hours. The presence of food did not affect the peak concentration or area under the curve of bupropion. XL formulations provide a 24-hour extended release of medication and are therefore generally dosed once per day/ In a trial comparing chronic dosing with bupropion hydrochloride extended-release tablets (SR) 150 mg twice daily to bupropion immediate-release formulation 100 mg 3 times daily, the steady state Cmax for bupropion after bupropion hydrochloride sustained-release tablets (SR) administration was approximately 85% of those achieved after bupropion immediate-release formulation administration. Exposure (AUC) to bupropion was equivalent for both formulations. Bioequivalence was also demonstrated for all three major active metabolites (i.e., hydroxybupropion, threohydrobupropion and erythrohydrobupropion) for both Cmax and AUC. Thus, at steady state, bupropion hydrochloride sustained-release tablets (SR) given twice daily, and the immediate-release formulation of bupropion given 3 times daily, are essentially bioequivalent for both bupropion and the 3 quantitatively important metabolites. Furthermore, in a study comparing 14-day dosing with bupropion hydrochloride extended-release tablets (XL), 300 mg once-daily to the immediate-release formulation of bupropion at 100 mg 3 times daily, equivalence was demonstrated for peak plasma concentration and area under the curve for bupropion and the three metabolites (hydroxybupropion, threohydrobupropion, and erythrohydrobupropion). Additionally, in a study comparing 14-day dosing with bupropion hydrochloride extended-release tablets (XL) 300 mg once daily to the sustained-release formulation of bupropion at 150 mg 2 times daily, equivalence was demonstrated for peak plasma concentration and area under the curve for bupropion and the three metabolites. Bupropion hydrochloride extended-release tablets (SR) can be taken with or without food. Bupropion Cmax and AUC were increased by 11% to 35% and 16% to 19%, respectively, when bupropion hydrochloride extended-release tablets (SR) was administered with food to healthy volunteers in three trials. The food effect is not considered clinically significant. Following a single-dose administration of bupropion hydrochloride extended-release tablets (SR) in humans, Cmax of bupropion's metabolite hydroxybupropion occurs approximately 6 hours post-dose and is approximately 10 times the peak level of the parent drug at steady state. The elimination half-life of hydroxybupropion is approximately 20 (±5) hours and its AUC at steady state is about 17 times that of bupropion. The times to peak concentrations for the erythrohydrobupropion and threohydrobupropion metabolites are similar to that of the hydroxybupropion metabolite. However, their elimination half-lives are longer, 33(±10) and 37 (±13) hours, respectively, and steady-state AUCs are 1.5 and 7 times that of bupropion, respectively. •Absorption (Drug B): Metoclopramide is rapidly absorbed in the gastrointestinal tract with an absorption rate of about 84%. The bioavailability of the oral preparation is reported to be about 40.7%, but can range from 30-100%. Nasal metoclopramide is 47% bioavailable. A 15mg dose reaches a C max of 41.0 ng/mL, with a T max of 1.25 h, and an AUC of 367 ng*h/mL. •Volume of distribution (Drug A): No volume of distribution available •Volume of distribution (Drug B): The volume of distribution of metoclopramide is approximately 3.5 L/kg. This implies a high level of tissue distribution. Metoclopramide crosses the placental barrier and can cause extrapyramidal symptoms in the fetus. •Protein binding (Drug A): In vitro tests show that bupropion is 84% bound to human plasma proteins at concentrations up to 200 mcg per mL. The extent of protein binding of the hydroxybupropion metabolite is similar to that for bupropion, whereas the extent of protein binding of the threohydrobupropion metabolite is about half that seen with bupropion. •Protein binding (Drug B): Metoclopramide is 30% bound to plasma proteins, mainly to alpha-1-acid glycoprotein. •Metabolism (Drug A): Bupropion is extensively metabolized in humans. Three metabolites are active: hydroxybupropion, which is formed via hydroxylation of the tert-butyl group of bupropion, and the amino-alcohol isomers, threohydrobupropion and erythrohydrobupropion, which are formed via reduction of the carbonyl group. In vitro findings suggest that CYP2B6 is the principal isoenzyme involved in the formation of hydroxybupropion, while cytochrome P450 enzymes are not involved in the formation of threohydrobupropion. Hydroxybupropion has been shown to have the same affinity as bupropion for the norepinephrine transporter (NET) but approximately 50% of its antidepressant activity despite reaching concentrations of ~10-fold higher than that of the parent drug. Oxidation of the bupropion side chain results in the formation of a glycine conjugate of meta-chlorobenzoic acid, which is then excreted as the major urinary metabolite. The potency and toxicity of the metabolites relative to bupropion have not been fully characterized. However, it has been demonstrated in an antidepressant screening test in mice that hydroxybupropion is one-half as potent as bupropion, while threohydrobupropion and erythrohydrobupropion are 5-fold less potent than bupropion. This may be of clinical importance because the plasma concentrations of the metabolites are as high as or higher than those of bupropion. Bupropion and its metabolites exhibit linear kinetics following chronic administration of 300 to 450 mg per day. •Metabolism (Drug B): Metoclopramide undergoes first-pass metabolism and its metabolism varies according to the individual. This drug is metabolized by cytochrome P450 enzymes in the liver. CYP2D6 and CYP3A4 both contribute to its metabolism, with CYP2D6 being more heavily involved. CYP1A2 is also a minor contributing enzyme. The process of N-4 sulphate conjugation is a primary metabolic pathway of metoclopramide. •Route of elimination (Drug A): Bupropion is extensively metabolized in humans. Oxidation of the bupropion side chain results in the formation of a glycine conjugate of metachlorobenzoic acid, which is then excreted as the major urinary metabolite. Following oral administration of 200 mg of 14C-bupropion in humans, 87% and 10% of the radioactive dose were recovered in the urine and feces, respectively. However, the fraction of the oral dose of bupropion excreted unchanged was only 0.5%, a finding consistent with the extensive metabolism of bupropion. •Route of elimination (Drug B): About 85% of an orally administered dose was measured in the urine within 72 hours during a pharmacokinetic study. An average of 18% to 22% of 10-20 mg dose was recovered as free drug within 3 days of administration. •Half-life (Drug A): 24 hours •Half-life (Drug B): The mean elimination half-life of metoclopramide in people with healthy renal function ranges from 5 to 6 hours but is prolonged in patients with renal impairment. Downward dose adjustment should be considered. •Clearance (Drug A): No clearance available •Clearance (Drug B): The renal clearance of metoclopramide is 0.16 L/h/kg with a total clearance of 0.7 L/h/kg. Clinical studies showed that the clearance of metoclopramide may be reduced by up to 50% in patients with renal impairment. After high intravenous doses, total metoclopramide clearance ranged from 0.31 to 0.69 L/kg/h. •Toxicity (Drug A): Symptoms of overdose include seizures, hallucinations, loss of consciousness, tachycardia, and cardiac arrest. •Toxicity (Drug B): The rat oral LD50 of metoclopramide is 750 mg/kg. Some symptoms of an overdose with metoclopramide include drowsiness, disorientation, and extrapyramidal reactions. Drugs that manage Parkinson's disease or anticholinergic drugs or antihistamines with anticholinergic properties should be employed to treat extrapyramidal symptoms. Normally, these symptoms subside within 24 hours. Unintentional overdose in infants receiving the oral solution of metoclopramide resulted in seizures, extrapyramidal symptoms, in addition to a lethargic state. In addition, methemoglobinemia has been found to occur in premature and full-term neonates after a metoclopramide overdose. Intravenous methylene blue may treat metoclopramide-associated methemoglobinemia. It is important to note that methylene blue administration may lead to hemolytic anemia in patients who suffer from G6PD deficiency, which can result in fatality. Dialysis has not been shown to be effective in sufficiently eliminating metoclopramide in an overdose situation due to low plasma distribution of this drug. •Brand Names (Drug A): Aplenzin, Auvelity, Budeprion, Contrave, Forfivo, Wellbutrin, Zyban •Brand Names (Drug B): Gimoti, Reglan •Synonyms (Drug A): No synonyms listed •Synonyms (Drug B): Metoclopramida Metoclopramide Metoclopramidum •Summary (Drug A): Bupropion is a norepinephrine and dopamine reuptake inhibitor used in the treatment of major depressive disorder (MDD), seasonal affective disorder (SAD), and as an aid to smoking cessation. •Summary (Drug B): Metoclopramide is an antiemetic agent and dopamine D2 antagonist used in the treatment of gastroesophageal reflux disease, prevention of nausea and vomiting, and to stimulate gastric emptying.

When coadministered with central nervous system depressants, metoclopramide may cause enhanced sedation due to additive effects. Both drugs have the propensity to cause sedation, leading to significant effects when administered concomitantly. The severity of the interaction is moderate.

Question: Does Bupropion and Metoclopramide interact? Information: •Drug A: Bupropion •Drug B: Metoclopramide •Severity: MODERATE •Description: The risk or severity of sedation can be increased when Metoclopramide is combined with Bupropion. •Extended Description: When coadministered with central nervous system depressants, metoclopramide may cause enhanced sedation due to additive effects. Both drugs have the propensity to cause sedation, leading to significant effects when administered concomitantly. •Indication (Drug A): Bupropion is indicated for the treatment of major depressive disorder (MDD), seasonal affective disorder (SAD), and as an aid to smoking cessation. When used in combination with naltrexone as the marketed product ContraveⓇ, bupropion is indicated as an adjunct to a reduced-calorie diet and increased physical activity for chronic weight management in adults with an initial body mass index (BMI) of: 30 kg/m^2 or greater (obese) or 27 kg/m^2 or greater (overweight) in the presence of at least one weight-related comorbid condition (e.g., hypertension, type 2 diabetes mellitus, or dyslipidemia). Bupropion is also used off-label as a first-line treatment in patients with ADHD and comorbid bipolar disorder when used as an adjunct to mood stabilizers. •Indication (Drug B): Metoclopramide in the oral tablet form is used for symptomatic treatment of both acute and recurrent diabetic gastroparesis, in addition to the treatment of gastroesophageal reflux disease (GERD) in patients who have failed to respond to traditional therapy. A nasal spray formulation is also indicated to treat adults with acute, recurrent diabetic gastroparesis. In the intravenous injection form, it is indicated for the above conditions as well as for the prevention of vomiting that may follow emetogenic chemotherapy or nausea and vomiting after surgery. Intravenous metoclopramide facilitates intubation of the small bowel and stimulates gastric emptying and barium flow in patients who require radiological examination of the stomach or small intestine. In some cases, the delay of gastrointestinal emptying interferes with the radiographic visualization of the gastrointestinal tract, and metoclopramide is used to facilitate emptying in these cases, allowing for adequate diagnostic visualization. Some off-label uses of metoclopramide include the management of radiation-induced nausea and vomiting, gastric bezoars, intractable hiccups, and migraine pain. •Pharmacodynamics (Drug A): Bupropion is chemically unrelated to tricyclic, tetracyclic, selective serotonin re-uptake inhibitors, or other known antidepressant agents. Compared to classical tricyclic antidepressants, Bupropion is a relatively weak inhibitor of the neuronal uptake of norepinephrine and dopamine. In addition, Bupropion does not inhibit monoamine oxidase. Bupropion has been found to be essentially inactive at the serotonin transporter (SERT)(IC50 >10 000 nM), however both bupropion and its primary metabolite hydroxybupropion have been found to block the function of cation-selective serotonin type 3A receptors (5-HT3ARs). Bupropion produces dose-related central nervous system (CNS) stimulant effects in animals, as evidenced by increased locomotor activity, increased rates of responding in various schedule-controlled operant behaviour tasks, and, at high doses, induction of mild stereotyped behaviour. Due to these stimulant effects and selective activity at dopamine and norepinephrine receptors, bupropion has been identified as having an abuse potential. Bupropion has a similar structure to the controlled substance Cathinone, and has been identified as having mild amphetamine-like activity, particularly when inhaled or injected. Bupropion is also known to lower the seizure threshold, making any pre-existing seizure conditions a contraindication to its use. This risk is exacerbated when bupropion is combined with other drugs or substances that lower the seizure threshold, such as cocaine, or in clinical situations that would increase the risk of a seizure such as abrupt alcohol or benzodiazepine withdrawal. As norepinephrine has been shown to have anticonvulsant properties, bupropion's inhibitory effects on NET are thought to contribute to its pro-convulsant activity. Bupropion has been shown to increase blood pressure and pose a risk for exacerbation of unmanaged or pre-existing hypertension, however, clinical trials of bupropion in smokers with CVD have not identified an increased incidence of CV events including stroke or heart attack. In clinical trials, the mean increase in systolic blood pressure associated with the use of bupropion was found to be 1.3 mmHg. •Pharmacodynamics (Drug B): Metoclopramide increases gastric emptying by decreasing lower esophageal sphincter (LES) pressure. It also exerts effects on the area postrema of the brain, preventing and relieving the symptoms of nausea and vomiting. In addition, this drug increases gastrointestinal motility without increasing biliary, gastric, or pancreatic secretions. Because of its antidopaminergic activity, metoclopramide can cause symptoms of tardive dyskinesia (TD), dystonia, and akathisia, and should therefore not be administered for longer than 12 weeks. •Mechanism of action (Drug A): Bupropion is a norepinephrine/dopamine-reuptake inhibitor (NDRI) that exerts its pharmacological effects by weakly inhibiting the enzymes involved in the uptake of the neurotransmitters norepinephrine and dopamine from the synaptic cleft, therefore prolonging their duration of action within the neuronal synapse and the downstream effects of these neurotransmitters. More specifically, bupropion binds to the norepinephrine transporter (NET) and the dopamine transporter (DAT). Bupropion was originally classified as an "atypical" antidepressant because it does not exert the same effects as the classical antidepressants such as Monoamine Oxidase Inhibitors (MAOIs), Tricyclic Antidepressants (TCAs), or Selective Serotonin Reuptake Inhibitors (SSRIs). While it has comparable effectiveness to typical first-line options for the treatment of depression such as SSRIs, bupropion is a unique option for the treatment of MDD as it lacks any clinically relevant serotonergic effects, typical of other mood medications, or any effects on histamine or adrenaline receptors. Lack of activity at these receptors results in a more tolerable side effect profile; bupropion is less likely to cause sexual side effects, sedation, or weight gain as compared to SSRIs or TCAs, for example. When used as an aid to smoking cessation, bupropion is thought to confer its anti-craving and anti-withdrawal effects by inhibiting dopamine reuptake, which is thought to be involved in the reward pathways associated with nicotine, and through the antagonism of the nicotinic acetylcholinergic receptor (AChR), thereby blunting the effects of nicotine. Furthermore, the stimulatory effects produced by bupropion in the central nervous system are similar to nicotine's effects, making low doses of bupropion a suitable option as a nicotine substitute. When used in combination with naltrexone in the marketed product ContraveⓇ for chronic weight management, the two components are thought to have effects on areas of the brain involved in the regulation of food intake. This includes the hypothalamus, which is involved in appetite regulation, and the mesolimbic dopamine circuit, which is involved in reward pathways. Studies have shown that the combined activity of bupropion and naltrexone increase the firing rate of hypothalamic pro-opiomelanocortin (POMC) neurons and blockade of opioid receptor-mediated POMC auto-inhibition, which are associated with a reduction in food intake and increased energy expenditure. This combination was also found to reduce food intake when injected directly into the ventral tegmental area of the mesolimbic circuit in mice, which is an area associated with the regulation of reward pathways. •Mechanism of action (Drug B): Metoclopramide causes antiemetic effects by inhibiting dopamine D2 and serotonin 5-HT3 receptors in the chemoreceptor trigger zone (CTZ) located in the area postrema of the brain. Administration of this drug leads to prokinetic effects via inhibitory actions on presynaptic and postsynaptic D2 receptors, agonism of serotonin 5-HT4 receptors, and antagonism of muscarinic receptor inhibition. This action enhances the release of acetylcholine, causing increased lower esophageal sphincter (LES) and gastric tone, accelerating gastric emptying and transit through the gut. Metoclopramide antagonizes the dopamine D2 receptors. Dopamine exerts relaxant effect on the gastrointestinal tract through binding to muscular D2 receptors. •Absorption (Drug A): Bupropion is currently available in 3 distinct, but bioequivalent formulations: immediate release (IR), sustained-release (SR), and extended-release (XL). Immediate Release Formulation In humans, following oral administration of bupropion hydrochloride tablets, peak plasma bupropion concentrations are usually achieved within 2 hours. IR formulations provide a short duration of action and are therefore generally dosed three times per day. Sustained Release Formulation In humans, following oral administration of bupropion hydrochloride sustained-release tablets (SR), peak plasma concentration (Cmax) of bupropion is usually achieved within 3 hours. SR formulations provide a 12-hour extended release of medication and are therefore generally dosed twice per day. Extended Release Formulation Following single oral administration of bupropion hydrochloride extended-release tablets (XL) to healthy volunteers, the median time to peak plasma concentrations for bupropion was approximately 5 hours. The presence of food did not affect the peak concentration or area under the curve of bupropion. XL formulations provide a 24-hour extended release of medication and are therefore generally dosed once per day/ In a trial comparing chronic dosing with bupropion hydrochloride extended-release tablets (SR) 150 mg twice daily to bupropion immediate-release formulation 100 mg 3 times daily, the steady state Cmax for bupropion after bupropion hydrochloride sustained-release tablets (SR) administration was approximately 85% of those achieved after bupropion immediate-release formulation administration. Exposure (AUC) to bupropion was equivalent for both formulations. Bioequivalence was also demonstrated for all three major active metabolites (i.e., hydroxybupropion, threohydrobupropion and erythrohydrobupropion) for both Cmax and AUC. Thus, at steady state, bupropion hydrochloride sustained-release tablets (SR) given twice daily, and the immediate-release formulation of bupropion given 3 times daily, are essentially bioequivalent for both bupropion and the 3 quantitatively important metabolites. Furthermore, in a study comparing 14-day dosing with bupropion hydrochloride extended-release tablets (XL), 300 mg once-daily to the immediate-release formulation of bupropion at 100 mg 3 times daily, equivalence was demonstrated for peak plasma concentration and area under the curve for bupropion and the three metabolites (hydroxybupropion, threohydrobupropion, and erythrohydrobupropion). Additionally, in a study comparing 14-day dosing with bupropion hydrochloride extended-release tablets (XL) 300 mg once daily to the sustained-release formulation of bupropion at 150 mg 2 times daily, equivalence was demonstrated for peak plasma concentration and area under the curve for bupropion and the three metabolites. Bupropion hydrochloride extended-release tablets (SR) can be taken with or without food. Bupropion Cmax and AUC were increased by 11% to 35% and 16% to 19%, respectively, when bupropion hydrochloride extended-release tablets (SR) was administered with food to healthy volunteers in three trials. The food effect is not considered clinically significant. Following a single-dose administration of bupropion hydrochloride extended-release tablets (SR) in humans, Cmax of bupropion's metabolite hydroxybupropion occurs approximately 6 hours post-dose and is approximately 10 times the peak level of the parent drug at steady state. The elimination half-life of hydroxybupropion is approximately 20 (±5) hours and its AUC at steady state is about 17 times that of bupropion. The times to peak concentrations for the erythrohydrobupropion and threohydrobupropion metabolites are similar to that of the hydroxybupropion metabolite. However, their elimination half-lives are longer, 33(±10) and 37 (±13) hours, respectively, and steady-state AUCs are 1.5 and 7 times that of bupropion, respectively. •Absorption (Drug B): Metoclopramide is rapidly absorbed in the gastrointestinal tract with an absorption rate of about 84%. The bioavailability of the oral preparation is reported to be about 40.7%, but can range from 30-100%. Nasal metoclopramide is 47% bioavailable. A 15mg dose reaches a C max of 41.0 ng/mL, with a T max of 1.25 h, and an AUC of 367 ng*h/mL. •Volume of distribution (Drug A): No volume of distribution available •Volume of distribution (Drug B): The volume of distribution of metoclopramide is approximately 3.5 L/kg. This implies a high level of tissue distribution. Metoclopramide crosses the placental barrier and can cause extrapyramidal symptoms in the fetus. •Protein binding (Drug A): In vitro tests show that bupropion is 84% bound to human plasma proteins at concentrations up to 200 mcg per mL. The extent of protein binding of the hydroxybupropion metabolite is similar to that for bupropion, whereas the extent of protein binding of the threohydrobupropion metabolite is about half that seen with bupropion. •Protein binding (Drug B): Metoclopramide is 30% bound to plasma proteins, mainly to alpha-1-acid glycoprotein. •Metabolism (Drug A): Bupropion is extensively metabolized in humans. Three metabolites are active: hydroxybupropion, which is formed via hydroxylation of the tert-butyl group of bupropion, and the amino-alcohol isomers, threohydrobupropion and erythrohydrobupropion, which are formed via reduction of the carbonyl group. In vitro findings suggest that CYP2B6 is the principal isoenzyme involved in the formation of hydroxybupropion, while cytochrome P450 enzymes are not involved in the formation of threohydrobupropion. Hydroxybupropion has been shown to have the same affinity as bupropion for the norepinephrine transporter (NET) but approximately 50% of its antidepressant activity despite reaching concentrations of ~10-fold higher than that of the parent drug. Oxidation of the bupropion side chain results in the formation of a glycine conjugate of meta-chlorobenzoic acid, which is then excreted as the major urinary metabolite. The potency and toxicity of the metabolites relative to bupropion have not been fully characterized. However, it has been demonstrated in an antidepressant screening test in mice that hydroxybupropion is one-half as potent as bupropion, while threohydrobupropion and erythrohydrobupropion are 5-fold less potent than bupropion. This may be of clinical importance because the plasma concentrations of the metabolites are as high as or higher than those of bupropion. Bupropion and its metabolites exhibit linear kinetics following chronic administration of 300 to 450 mg per day. •Metabolism (Drug B): Metoclopramide undergoes first-pass metabolism and its metabolism varies according to the individual. This drug is metabolized by cytochrome P450 enzymes in the liver. CYP2D6 and CYP3A4 both contribute to its metabolism, with CYP2D6 being more heavily involved. CYP1A2 is also a minor contributing enzyme. The process of N-4 sulphate conjugation is a primary metabolic pathway of metoclopramide. •Route of elimination (Drug A): Bupropion is extensively metabolized in humans. Oxidation of the bupropion side chain results in the formation of a glycine conjugate of metachlorobenzoic acid, which is then excreted as the major urinary metabolite. Following oral administration of 200 mg of 14C-bupropion in humans, 87% and 10% of the radioactive dose were recovered in the urine and feces, respectively. However, the fraction of the oral dose of bupropion excreted unchanged was only 0.5%, a finding consistent with the extensive metabolism of bupropion. •Route of elimination (Drug B): About 85% of an orally administered dose was measured in the urine within 72 hours during a pharmacokinetic study. An average of 18% to 22% of 10-20 mg dose was recovered as free drug within 3 days of administration. •Half-life (Drug A): 24 hours •Half-life (Drug B): The mean elimination half-life of metoclopramide in people with healthy renal function ranges from 5 to 6 hours but is prolonged in patients with renal impairment. Downward dose adjustment should be considered. •Clearance (Drug A): No clearance available •Clearance (Drug B): The renal clearance of metoclopramide is 0.16 L/h/kg with a total clearance of 0.7 L/h/kg. Clinical studies showed that the clearance of metoclopramide may be reduced by up to 50% in patients with renal impairment. After high intravenous doses, total metoclopramide clearance ranged from 0.31 to 0.69 L/kg/h. •Toxicity (Drug A): Symptoms of overdose include seizures, hallucinations, loss of consciousness, tachycardia, and cardiac arrest. •Toxicity (Drug B): The rat oral LD50 of metoclopramide is 750 mg/kg. Some symptoms of an overdose with metoclopramide include drowsiness, disorientation, and extrapyramidal reactions. Drugs that manage Parkinson's disease or anticholinergic drugs or antihistamines with anticholinergic properties should be employed to treat extrapyramidal symptoms. Normally, these symptoms subside within 24 hours. Unintentional overdose in infants receiving the oral solution of metoclopramide resulted in seizures, extrapyramidal symptoms, in addition to a lethargic state. In addition, methemoglobinemia has been found to occur in premature and full-term neonates after a metoclopramide overdose. Intravenous methylene blue may treat metoclopramide-associated methemoglobinemia. It is important to note that methylene blue administration may lead to hemolytic anemia in patients who suffer from G6PD deficiency, which can result in fatality. Dialysis has not been shown to be effective in sufficiently eliminating metoclopramide in an overdose situation due to low plasma distribution of this drug. •Brand Names (Drug A): Aplenzin, Auvelity, Budeprion, Contrave, Forfivo, Wellbutrin, Zyban •Brand Names (Drug B): Gimoti, Reglan •Synonyms (Drug A): No synonyms listed •Synonyms (Drug B): Metoclopramida Metoclopramide Metoclopramidum •Summary (Drug A): Bupropion is a norepinephrine and dopamine reuptake inhibitor used in the treatment of major depressive disorder (MDD), seasonal affective disorder (SAD), and as an aid to smoking cessation. •Summary (Drug B): Metoclopramide is an antiemetic agent and dopamine D2 antagonist used in the treatment of gastroesophageal reflux disease, prevention of nausea and vomiting, and to stimulate gastric emptying. Output: When coadministered with central nervous system depressants, metoclopramide may cause enhanced sedation due to additive effects. Both drugs have the propensity to cause sedation, leading to significant effects when administered concomitantly. The severity of the interaction is moderate.

Does Bupropion and Metolazone interact?

•Drug A: Bupropion •Drug B: Metolazone •Severity: MODERATE •Description: Metolazone may increase the excretion rate of Bupropion which could result in a lower serum level and potentially a reduction in efficacy. •Extended Description: The subject drug induces diuresis1,2, which can theoretically increase the excretion rate of the affected drug, which is eliminated by the kidneys. Additionally, it could affect renal tubular reabsorption of certain drugs. Exposure to the affected drug can be markedly reduced, leading to subtherapeutic drug levels that are unlikely to elicit an adequate clinical response. •Indication (Drug A): Bupropion is indicated for the treatment of major depressive disorder (MDD), seasonal affective disorder (SAD), and as an aid to smoking cessation. When used in combination with naltrexone as the marketed product ContraveⓇ, bupropion is indicated as an adjunct to a reduced-calorie diet and increased physical activity for chronic weight management in adults with an initial body mass index (BMI) of: 30 kg/m^2 or greater (obese) or 27 kg/m^2 or greater (overweight) in the presence of at least one weight-related comorbid condition (e.g., hypertension, type 2 diabetes mellitus, or dyslipidemia). Bupropion is also used off-label as a first-line treatment in patients with ADHD and comorbid bipolar disorder when used as an adjunct to mood stabilizers. •Indication (Drug B): For the treatment of hypertension, alone or in combination with other antihypertensive drugs of a different class. •Pharmacodynamics (Drug A): Bupropion is chemically unrelated to tricyclic, tetracyclic, selective serotonin re-uptake inhibitors, or other known antidepressant agents. Compared to classical tricyclic antidepressants, Bupropion is a relatively weak inhibitor of the neuronal uptake of norepinephrine and dopamine. In addition, Bupropion does not inhibit monoamine oxidase. Bupropion has been found to be essentially inactive at the serotonin transporter (SERT)(IC50 >10 000 nM), however both bupropion and its primary metabolite hydroxybupropion have been found to block the function of cation-selective serotonin type 3A receptors (5-HT3ARs). Bupropion produces dose-related central nervous system (CNS) stimulant effects in animals, as evidenced by increased locomotor activity, increased rates of responding in various schedule-controlled operant behaviour tasks, and, at high doses, induction of mild stereotyped behaviour. Due to these stimulant effects and selective activity at dopamine and norepinephrine receptors, bupropion has been identified as having an abuse potential. Bupropion has a similar structure to the controlled substance Cathinone, and has been identified as having mild amphetamine-like activity, particularly when inhaled or injected. Bupropion is also known to lower the seizure threshold, making any pre-existing seizure conditions a contraindication to its use. This risk is exacerbated when bupropion is combined with other drugs or substances that lower the seizure threshold, such as cocaine, or in clinical situations that would increase the risk of a seizure such as abrupt alcohol or benzodiazepine withdrawal. As norepinephrine has been shown to have anticonvulsant properties, bupropion's inhibitory effects on NET are thought to contribute to its pro-convulsant activity. Bupropion has been shown to increase blood pressure and pose a risk for exacerbation of unmanaged or pre-existing hypertension, however, clinical trials of bupropion in smokers with CVD have not identified an increased incidence of CV events including stroke or heart attack. In clinical trials, the mean increase in systolic blood pressure associated with the use of bupropion was found to be 1.3 mmHg. •Pharmacodynamics (Drug B): Metolazone is a quinazoline diuretic, with properties generally similar to the thiazide diuretics. A proximal action of metolazone has been shown in humans by increased excretion of phosphate and magnesium ions and by a markedly increased fractional excretion of sodium in patients with severely compromised glomerular filtration. This action has been demonstrated in animals by micropuncture studies. •Mechanism of action (Drug A): Bupropion is a norepinephrine/dopamine-reuptake inhibitor (NDRI) that exerts its pharmacological effects by weakly inhibiting the enzymes involved in the uptake of the neurotransmitters norepinephrine and dopamine from the synaptic cleft, therefore prolonging their duration of action within the neuronal synapse and the downstream effects of these neurotransmitters. More specifically, bupropion binds to the norepinephrine transporter (NET) and the dopamine transporter (DAT). Bupropion was originally classified as an "atypical" antidepressant because it does not exert the same effects as the classical antidepressants such as Monoamine Oxidase Inhibitors (MAOIs), Tricyclic Antidepressants (TCAs), or Selective Serotonin Reuptake Inhibitors (SSRIs). While it has comparable effectiveness to typical first-line options for the treatment of depression such as SSRIs, bupropion is a unique option for the treatment of MDD as it lacks any clinically relevant serotonergic effects, typical of other mood medications, or any effects on histamine or adrenaline receptors. Lack of activity at these receptors results in a more tolerable side effect profile; bupropion is less likely to cause sexual side effects, sedation, or weight gain as compared to SSRIs or TCAs, for example. When used as an aid to smoking cessation, bupropion is thought to confer its anti-craving and anti-withdrawal effects by inhibiting dopamine reuptake, which is thought to be involved in the reward pathways associated with nicotine, and through the antagonism of the nicotinic acetylcholinergic receptor (AChR), thereby blunting the effects of nicotine. Furthermore, the stimulatory effects produced by bupropion in the central nervous system are similar to nicotine's effects, making low doses of bupropion a suitable option as a nicotine substitute. When used in combination with naltrexone in the marketed product ContraveⓇ for chronic weight management, the two components are thought to have effects on areas of the brain involved in the regulation of food intake. This includes the hypothalamus, which is involved in appetite regulation, and the mesolimbic dopamine circuit, which is involved in reward pathways. Studies have shown that the combined activity of bupropion and naltrexone increase the firing rate of hypothalamic pro-opiomelanocortin (POMC) neurons and blockade of opioid receptor-mediated POMC auto-inhibition, which are associated with a reduction in food intake and increased energy expenditure. This combination was also found to reduce food intake when injected directly into the ventral tegmental area of the mesolimbic circuit in mice, which is an area associated with the regulation of reward pathways. •Mechanism of action (Drug B): The actions of metolazone result from interference with the renal tubular mechanism of electrolyte reabsorption. Metolazone acts primarily to inhibit sodium reabsorption at the cortical diluting site and to a lesser extent in the proximal convoluted tubule. Sodium and chloride ions are excreted in approximately equivalent amounts. The increased delivery of sodium to the distal tubular exchange site results in increased potassium excretion. Metolazone does not inhibit carbonic anhydrase. The antihypertensive mechanism of action of metolazone is not fully understood but is presumed to be related to its saluretic and diuretic properties. •Absorption (Drug A): Bupropion is currently available in 3 distinct, but bioequivalent formulations: immediate release (IR), sustained-release (SR), and extended-release (XL). Immediate Release Formulation In humans, following oral administration of bupropion hydrochloride tablets, peak plasma bupropion concentrations are usually achieved within 2 hours. IR formulations provide a short duration of action and are therefore generally dosed three times per day. Sustained Release Formulation In humans, following oral administration of bupropion hydrochloride sustained-release tablets (SR), peak plasma concentration (Cmax) of bupropion is usually achieved within 3 hours. SR formulations provide a 12-hour extended release of medication and are therefore generally dosed twice per day. Extended Release Formulation Following single oral administration of bupropion hydrochloride extended-release tablets (XL) to healthy volunteers, the median time to peak plasma concentrations for bupropion was approximately 5 hours. The presence of food did not affect the peak concentration or area under the curve of bupropion. XL formulations provide a 24-hour extended release of medication and are therefore generally dosed once per day/ In a trial comparing chronic dosing with bupropion hydrochloride extended-release tablets (SR) 150 mg twice daily to bupropion immediate-release formulation 100 mg 3 times daily, the steady state Cmax for bupropion after bupropion hydrochloride sustained-release tablets (SR) administration was approximately 85% of those achieved after bupropion immediate-release formulation administration. Exposure (AUC) to bupropion was equivalent for both formulations. Bioequivalence was also demonstrated for all three major active metabolites (i.e., hydroxybupropion, threohydrobupropion and erythrohydrobupropion) for both Cmax and AUC. Thus, at steady state, bupropion hydrochloride sustained-release tablets (SR) given twice daily, and the immediate-release formulation of bupropion given 3 times daily, are essentially bioequivalent for both bupropion and the 3 quantitatively important metabolites. Furthermore, in a study comparing 14-day dosing with bupropion hydrochloride extended-release tablets (XL), 300 mg once-daily to the immediate-release formulation of bupropion at 100 mg 3 times daily, equivalence was demonstrated for peak plasma concentration and area under the curve for bupropion and the three metabolites (hydroxybupropion, threohydrobupropion, and erythrohydrobupropion). Additionally, in a study comparing 14-day dosing with bupropion hydrochloride extended-release tablets (XL) 300 mg once daily to the sustained-release formulation of bupropion at 150 mg 2 times daily, equivalence was demonstrated for peak plasma concentration and area under the curve for bupropion and the three metabolites. Bupropion hydrochloride extended-release tablets (SR) can be taken with or without food. Bupropion Cmax and AUC were increased by 11% to 35% and 16% to 19%, respectively, when bupropion hydrochloride extended-release tablets (SR) was administered with food to healthy volunteers in three trials. The food effect is not considered clinically significant. Following a single-dose administration of bupropion hydrochloride extended-release tablets (SR) in humans, Cmax of bupropion's metabolite hydroxybupropion occurs approximately 6 hours post-dose and is approximately 10 times the peak level of the parent drug at steady state. The elimination half-life of hydroxybupropion is approximately 20 (±5) hours and its AUC at steady state is about 17 times that of bupropion. The times to peak concentrations for the erythrohydrobupropion and threohydrobupropion metabolites are similar to that of the hydroxybupropion metabolite. However, their elimination half-lives are longer, 33(±10) and 37 (±13) hours, respectively, and steady-state AUCs are 1.5 and 7 times that of bupropion, respectively. •Absorption (Drug B): Peak blood levels are obtained within 2 to 4 hours of oral administration. The rate and extent of absorption are formulation dependent. •Volume of distribution (Drug A): No volume of distribution available •Volume of distribution (Drug B): No volume of distribution available •Protein binding (Drug A): In vitro tests show that bupropion is 84% bound to human plasma proteins at concentrations up to 200 mcg per mL. The extent of protein binding of the hydroxybupropion metabolite is similar to that for bupropion, whereas the extent of protein binding of the threohydrobupropion metabolite is about half that seen with bupropion. •Protein binding (Drug B): 50-70% bound to erythrocytes, up to 33% bound to plasma proteins, 2-5% of the drug in circulation is unbound •Metabolism (Drug A): Bupropion is extensively metabolized in humans. Three metabolites are active: hydroxybupropion, which is formed via hydroxylation of the tert-butyl group of bupropion, and the amino-alcohol isomers, threohydrobupropion and erythrohydrobupropion, which are formed via reduction of the carbonyl group. In vitro findings suggest that CYP2B6 is the principal isoenzyme involved in the formation of hydroxybupropion, while cytochrome P450 enzymes are not involved in the formation of threohydrobupropion. Hydroxybupropion has been shown to have the same affinity as bupropion for the norepinephrine transporter (NET) but approximately 50% of its antidepressant activity despite reaching concentrations of ~10-fold higher than that of the parent drug. Oxidation of the bupropion side chain results in the formation of a glycine conjugate of meta-chlorobenzoic acid, which is then excreted as the major urinary metabolite. The potency and toxicity of the metabolites relative to bupropion have not been fully characterized. However, it has been demonstrated in an antidepressant screening test in mice that hydroxybupropion is one-half as potent as bupropion, while threohydrobupropion and erythrohydrobupropion are 5-fold less potent than bupropion. This may be of clinical importance because the plasma concentrations of the metabolites are as high as or higher than those of bupropion. Bupropion and its metabolites exhibit linear kinetics following chronic administration of 300 to 450 mg per day. •Metabolism (Drug B): Not substantially metabolized. 70-95% is excreted unchanged in urine via glomerular filtration and active tubular secretion. Undergoes enterohepatic recycling. •Route of elimination (Drug A): Bupropion is extensively metabolized in humans. Oxidation of the bupropion side chain results in the formation of a glycine conjugate of metachlorobenzoic acid, which is then excreted as the major urinary metabolite. Following oral administration of 200 mg of 14C-bupropion in humans, 87% and 10% of the radioactive dose were recovered in the urine and feces, respectively. However, the fraction of the oral dose of bupropion excreted unchanged was only 0.5%, a finding consistent with the extensive metabolism of bupropion. •Route of elimination (Drug B): Most of the drug is excreted in the unconverted form in the urine. •Half-life (Drug A): 24 hours •Half-life (Drug B): Approximately 14 hours. •Clearance (Drug A): No clearance available •Clearance (Drug B): No clearance available •Toxicity (Drug A): Symptoms of overdose include seizures, hallucinations, loss of consciousness, tachycardia, and cardiac arrest. •Toxicity (Drug B): Symptoms of overdose include difficulty breathing, dizziness, dizziness on standing up, drowsiness, fainting, irritation of the stomach and intestines, and lethargy leading to coma. •Brand Names (Drug A): Aplenzin, Auvelity, Budeprion, Contrave, Forfivo, Wellbutrin, Zyban •Brand Names (Drug B): Mykrox, Zaroxolyn •Synonyms (Drug A): No synonyms listed •Synonyms (Drug B): Metolazon Metolazona Métolazone Metolazone Metolazonum •Summary (Drug A): Bupropion is a norepinephrine and dopamine reuptake inhibitor used in the treatment of major depressive disorder (MDD), seasonal affective disorder (SAD), and as an aid to smoking cessation. •Summary (Drug B): Metolazone is a thiazide-like diuretic used to treat hypertension.

The subject drug induces diuresis1,2, which can theoretically increase the excretion rate of the affected drug, which is eliminated by the kidneys. Additionally, it could affect renal tubular reabsorption of certain drugs. Exposure to the affected drug can be markedly reduced, leading to subtherapeutic drug levels that are unlikely to elicit an adequate clinical response. The severity of the interaction is moderate.

Question: Does Bupropion and Metolazone interact? Information: •Drug A: Bupropion •Drug B: Metolazone •Severity: MODERATE •Description: Metolazone may increase the excretion rate of Bupropion which could result in a lower serum level and potentially a reduction in efficacy. •Extended Description: The subject drug induces diuresis1,2, which can theoretically increase the excretion rate of the affected drug, which is eliminated by the kidneys. Additionally, it could affect renal tubular reabsorption of certain drugs. Exposure to the affected drug can be markedly reduced, leading to subtherapeutic drug levels that are unlikely to elicit an adequate clinical response. •Indication (Drug A): Bupropion is indicated for the treatment of major depressive disorder (MDD), seasonal affective disorder (SAD), and as an aid to smoking cessation. When used in combination with naltrexone as the marketed product ContraveⓇ, bupropion is indicated as an adjunct to a reduced-calorie diet and increased physical activity for chronic weight management in adults with an initial body mass index (BMI) of: 30 kg/m^2 or greater (obese) or 27 kg/m^2 or greater (overweight) in the presence of at least one weight-related comorbid condition (e.g., hypertension, type 2 diabetes mellitus, or dyslipidemia). Bupropion is also used off-label as a first-line treatment in patients with ADHD and comorbid bipolar disorder when used as an adjunct to mood stabilizers. •Indication (Drug B): For the treatment of hypertension, alone or in combination with other antihypertensive drugs of a different class. •Pharmacodynamics (Drug A): Bupropion is chemically unrelated to tricyclic, tetracyclic, selective serotonin re-uptake inhibitors, or other known antidepressant agents. Compared to classical tricyclic antidepressants, Bupropion is a relatively weak inhibitor of the neuronal uptake of norepinephrine and dopamine. In addition, Bupropion does not inhibit monoamine oxidase. Bupropion has been found to be essentially inactive at the serotonin transporter (SERT)(IC50 >10 000 nM), however both bupropion and its primary metabolite hydroxybupropion have been found to block the function of cation-selective serotonin type 3A receptors (5-HT3ARs). Bupropion produces dose-related central nervous system (CNS) stimulant effects in animals, as evidenced by increased locomotor activity, increased rates of responding in various schedule-controlled operant behaviour tasks, and, at high doses, induction of mild stereotyped behaviour. Due to these stimulant effects and selective activity at dopamine and norepinephrine receptors, bupropion has been identified as having an abuse potential. Bupropion has a similar structure to the controlled substance Cathinone, and has been identified as having mild amphetamine-like activity, particularly when inhaled or injected. Bupropion is also known to lower the seizure threshold, making any pre-existing seizure conditions a contraindication to its use. This risk is exacerbated when bupropion is combined with other drugs or substances that lower the seizure threshold, such as cocaine, or in clinical situations that would increase the risk of a seizure such as abrupt alcohol or benzodiazepine withdrawal. As norepinephrine has been shown to have anticonvulsant properties, bupropion's inhibitory effects on NET are thought to contribute to its pro-convulsant activity. Bupropion has been shown to increase blood pressure and pose a risk for exacerbation of unmanaged or pre-existing hypertension, however, clinical trials of bupropion in smokers with CVD have not identified an increased incidence of CV events including stroke or heart attack. In clinical trials, the mean increase in systolic blood pressure associated with the use of bupropion was found to be 1.3 mmHg. •Pharmacodynamics (Drug B): Metolazone is a quinazoline diuretic, with properties generally similar to the thiazide diuretics. A proximal action of metolazone has been shown in humans by increased excretion of phosphate and magnesium ions and by a markedly increased fractional excretion of sodium in patients with severely compromised glomerular filtration. This action has been demonstrated in animals by micropuncture studies. •Mechanism of action (Drug A): Bupropion is a norepinephrine/dopamine-reuptake inhibitor (NDRI) that exerts its pharmacological effects by weakly inhibiting the enzymes involved in the uptake of the neurotransmitters norepinephrine and dopamine from the synaptic cleft, therefore prolonging their duration of action within the neuronal synapse and the downstream effects of these neurotransmitters. More specifically, bupropion binds to the norepinephrine transporter (NET) and the dopamine transporter (DAT). Bupropion was originally classified as an "atypical" antidepressant because it does not exert the same effects as the classical antidepressants such as Monoamine Oxidase Inhibitors (MAOIs), Tricyclic Antidepressants (TCAs), or Selective Serotonin Reuptake Inhibitors (SSRIs). While it has comparable effectiveness to typical first-line options for the treatment of depression such as SSRIs, bupropion is a unique option for the treatment of MDD as it lacks any clinically relevant serotonergic effects, typical of other mood medications, or any effects on histamine or adrenaline receptors. Lack of activity at these receptors results in a more tolerable side effect profile; bupropion is less likely to cause sexual side effects, sedation, or weight gain as compared to SSRIs or TCAs, for example. When used as an aid to smoking cessation, bupropion is thought to confer its anti-craving and anti-withdrawal effects by inhibiting dopamine reuptake, which is thought to be involved in the reward pathways associated with nicotine, and through the antagonism of the nicotinic acetylcholinergic receptor (AChR), thereby blunting the effects of nicotine. Furthermore, the stimulatory effects produced by bupropion in the central nervous system are similar to nicotine's effects, making low doses of bupropion a suitable option as a nicotine substitute. When used in combination with naltrexone in the marketed product ContraveⓇ for chronic weight management, the two components are thought to have effects on areas of the brain involved in the regulation of food intake. This includes the hypothalamus, which is involved in appetite regulation, and the mesolimbic dopamine circuit, which is involved in reward pathways. Studies have shown that the combined activity of bupropion and naltrexone increase the firing rate of hypothalamic pro-opiomelanocortin (POMC) neurons and blockade of opioid receptor-mediated POMC auto-inhibition, which are associated with a reduction in food intake and increased energy expenditure. This combination was also found to reduce food intake when injected directly into the ventral tegmental area of the mesolimbic circuit in mice, which is an area associated with the regulation of reward pathways. •Mechanism of action (Drug B): The actions of metolazone result from interference with the renal tubular mechanism of electrolyte reabsorption. Metolazone acts primarily to inhibit sodium reabsorption at the cortical diluting site and to a lesser extent in the proximal convoluted tubule. Sodium and chloride ions are excreted in approximately equivalent amounts. The increased delivery of sodium to the distal tubular exchange site results in increased potassium excretion. Metolazone does not inhibit carbonic anhydrase. The antihypertensive mechanism of action of metolazone is not fully understood but is presumed to be related to its saluretic and diuretic properties. •Absorption (Drug A): Bupropion is currently available in 3 distinct, but bioequivalent formulations: immediate release (IR), sustained-release (SR), and extended-release (XL). Immediate Release Formulation In humans, following oral administration of bupropion hydrochloride tablets, peak plasma bupropion concentrations are usually achieved within 2 hours. IR formulations provide a short duration of action and are therefore generally dosed three times per day. Sustained Release Formulation In humans, following oral administration of bupropion hydrochloride sustained-release tablets (SR), peak plasma concentration (Cmax) of bupropion is usually achieved within 3 hours. SR formulations provide a 12-hour extended release of medication and are therefore generally dosed twice per day. Extended Release Formulation Following single oral administration of bupropion hydrochloride extended-release tablets (XL) to healthy volunteers, the median time to peak plasma concentrations for bupropion was approximately 5 hours. The presence of food did not affect the peak concentration or area under the curve of bupropion. XL formulations provide a 24-hour extended release of medication and are therefore generally dosed once per day/ In a trial comparing chronic dosing with bupropion hydrochloride extended-release tablets (SR) 150 mg twice daily to bupropion immediate-release formulation 100 mg 3 times daily, the steady state Cmax for bupropion after bupropion hydrochloride sustained-release tablets (SR) administration was approximately 85% of those achieved after bupropion immediate-release formulation administration. Exposure (AUC) to bupropion was equivalent for both formulations. Bioequivalence was also demonstrated for all three major active metabolites (i.e., hydroxybupropion, threohydrobupropion and erythrohydrobupropion) for both Cmax and AUC. Thus, at steady state, bupropion hydrochloride sustained-release tablets (SR) given twice daily, and the immediate-release formulation of bupropion given 3 times daily, are essentially bioequivalent for both bupropion and the 3 quantitatively important metabolites. Furthermore, in a study comparing 14-day dosing with bupropion hydrochloride extended-release tablets (XL), 300 mg once-daily to the immediate-release formulation of bupropion at 100 mg 3 times daily, equivalence was demonstrated for peak plasma concentration and area under the curve for bupropion and the three metabolites (hydroxybupropion, threohydrobupropion, and erythrohydrobupropion). Additionally, in a study comparing 14-day dosing with bupropion hydrochloride extended-release tablets (XL) 300 mg once daily to the sustained-release formulation of bupropion at 150 mg 2 times daily, equivalence was demonstrated for peak plasma concentration and area under the curve for bupropion and the three metabolites. Bupropion hydrochloride extended-release tablets (SR) can be taken with or without food. Bupropion Cmax and AUC were increased by 11% to 35% and 16% to 19%, respectively, when bupropion hydrochloride extended-release tablets (SR) was administered with food to healthy volunteers in three trials. The food effect is not considered clinically significant. Following a single-dose administration of bupropion hydrochloride extended-release tablets (SR) in humans, Cmax of bupropion's metabolite hydroxybupropion occurs approximately 6 hours post-dose and is approximately 10 times the peak level of the parent drug at steady state. The elimination half-life of hydroxybupropion is approximately 20 (±5) hours and its AUC at steady state is about 17 times that of bupropion. The times to peak concentrations for the erythrohydrobupropion and threohydrobupropion metabolites are similar to that of the hydroxybupropion metabolite. However, their elimination half-lives are longer, 33(±10) and 37 (±13) hours, respectively, and steady-state AUCs are 1.5 and 7 times that of bupropion, respectively. •Absorption (Drug B): Peak blood levels are obtained within 2 to 4 hours of oral administration. The rate and extent of absorption are formulation dependent. •Volume of distribution (Drug A): No volume of distribution available •Volume of distribution (Drug B): No volume of distribution available •Protein binding (Drug A): In vitro tests show that bupropion is 84% bound to human plasma proteins at concentrations up to 200 mcg per mL. The extent of protein binding of the hydroxybupropion metabolite is similar to that for bupropion, whereas the extent of protein binding of the threohydrobupropion metabolite is about half that seen with bupropion. •Protein binding (Drug B): 50-70% bound to erythrocytes, up to 33% bound to plasma proteins, 2-5% of the drug in circulation is unbound •Metabolism (Drug A): Bupropion is extensively metabolized in humans. Three metabolites are active: hydroxybupropion, which is formed via hydroxylation of the tert-butyl group of bupropion, and the amino-alcohol isomers, threohydrobupropion and erythrohydrobupropion, which are formed via reduction of the carbonyl group. In vitro findings suggest that CYP2B6 is the principal isoenzyme involved in the formation of hydroxybupropion, while cytochrome P450 enzymes are not involved in the formation of threohydrobupropion. Hydroxybupropion has been shown to have the same affinity as bupropion for the norepinephrine transporter (NET) but approximately 50% of its antidepressant activity despite reaching concentrations of ~10-fold higher than that of the parent drug. Oxidation of the bupropion side chain results in the formation of a glycine conjugate of meta-chlorobenzoic acid, which is then excreted as the major urinary metabolite. The potency and toxicity of the metabolites relative to bupropion have not been fully characterized. However, it has been demonstrated in an antidepressant screening test in mice that hydroxybupropion is one-half as potent as bupropion, while threohydrobupropion and erythrohydrobupropion are 5-fold less potent than bupropion. This may be of clinical importance because the plasma concentrations of the metabolites are as high as or higher than those of bupropion. Bupropion and its metabolites exhibit linear kinetics following chronic administration of 300 to 450 mg per day. •Metabolism (Drug B): Not substantially metabolized. 70-95% is excreted unchanged in urine via glomerular filtration and active tubular secretion. Undergoes enterohepatic recycling. •Route of elimination (Drug A): Bupropion is extensively metabolized in humans. Oxidation of the bupropion side chain results in the formation of a glycine conjugate of metachlorobenzoic acid, which is then excreted as the major urinary metabolite. Following oral administration of 200 mg of 14C-bupropion in humans, 87% and 10% of the radioactive dose were recovered in the urine and feces, respectively. However, the fraction of the oral dose of bupropion excreted unchanged was only 0.5%, a finding consistent with the extensive metabolism of bupropion. •Route of elimination (Drug B): Most of the drug is excreted in the unconverted form in the urine. •Half-life (Drug A): 24 hours •Half-life (Drug B): Approximately 14 hours. •Clearance (Drug A): No clearance available •Clearance (Drug B): No clearance available •Toxicity (Drug A): Symptoms of overdose include seizures, hallucinations, loss of consciousness, tachycardia, and cardiac arrest. •Toxicity (Drug B): Symptoms of overdose include difficulty breathing, dizziness, dizziness on standing up, drowsiness, fainting, irritation of the stomach and intestines, and lethargy leading to coma. •Brand Names (Drug A): Aplenzin, Auvelity, Budeprion, Contrave, Forfivo, Wellbutrin, Zyban •Brand Names (Drug B): Mykrox, Zaroxolyn •Synonyms (Drug A): No synonyms listed •Synonyms (Drug B): Metolazon Metolazona Métolazone Metolazone Metolazonum •Summary (Drug A): Bupropion is a norepinephrine and dopamine reuptake inhibitor used in the treatment of major depressive disorder (MDD), seasonal affective disorder (SAD), and as an aid to smoking cessation. •Summary (Drug B): Metolazone is a thiazide-like diuretic used to treat hypertension. Output: The subject drug induces diuresis1,2, which can theoretically increase the excretion rate of the affected drug, which is eliminated by the kidneys. Additionally, it could affect renal tubular reabsorption of certain drugs. Exposure to the affected drug can be markedly reduced, leading to subtherapeutic drug levels that are unlikely to elicit an adequate clinical response. The severity of the interaction is moderate.

Does Bupropion and Metoprolol interact?

•Drug A: Bupropion •Drug B: Metoprolol •Severity: MAJOR •Description: The metabolism of Metoprolol can be decreased when combined with Bupropion. •Extended Description: The subject drug is a strong CYP2D6 inhibitor and the affected drug is metabolized by CYP2D6. Concomitant administration may decrease the metabolism of the affected drug, which could increase serum concentrations as well as the risk and severity of adverse effects. •Indication (Drug A): Bupropion is indicated for the treatment of major depressive disorder (MDD), seasonal affective disorder (SAD), and as an aid to smoking cessation. When used in combination with naltrexone as the marketed product ContraveⓇ, bupropion is indicated as an adjunct to a reduced-calorie diet and increased physical activity for chronic weight management in adults with an initial body mass index (BMI) of: 30 kg/m^2 or greater (obese) or 27 kg/m^2 or greater (overweight) in the presence of at least one weight-related comorbid condition (e.g., hypertension, type 2 diabetes mellitus, or dyslipidemia). Bupropion is also used off-label as a first-line treatment in patients with ADHD and comorbid bipolar disorder when used as an adjunct to mood stabilizers. •Indication (Drug B): Metoprolol is indicated for the treatment of angina, heart failure, myocardial infarction, atrial fibrillation, atrial flutter and hypertension. Some off-label uses of metoprolol include supraventricular tachycardia and thyroid storm. All the indications of metoprolol are part of cardiovascular diseases. These conditions correspond to a number of diseases that involve the function of the heart and blood vessels. The underlying causes of these conditions are variable and can be due to genetic disposition, lifestyle decisions such as smoking, obesity, diet, and lack of exercise, and comorbidity with other conditions such as diabetes. The cardiovascular diseases are the leading cause of death on a global scale. •Pharmacodynamics (Drug A): Bupropion is chemically unrelated to tricyclic, tetracyclic, selective serotonin re-uptake inhibitors, or other known antidepressant agents. Compared to classical tricyclic antidepressants, Bupropion is a relatively weak inhibitor of the neuronal uptake of norepinephrine and dopamine. In addition, Bupropion does not inhibit monoamine oxidase. Bupropion has been found to be essentially inactive at the serotonin transporter (SERT)(IC50 >10 000 nM), however both bupropion and its primary metabolite hydroxybupropion have been found to block the function of cation-selective serotonin type 3A receptors (5-HT3ARs). Bupropion produces dose-related central nervous system (CNS) stimulant effects in animals, as evidenced by increased locomotor activity, increased rates of responding in various schedule-controlled operant behaviour tasks, and, at high doses, induction of mild stereotyped behaviour. Due to these stimulant effects and selective activity at dopamine and norepinephrine receptors, bupropion has been identified as having an abuse potential. Bupropion has a similar structure to the controlled substance Cathinone, and has been identified as having mild amphetamine-like activity, particularly when inhaled or injected. Bupropion is also known to lower the seizure threshold, making any pre-existing seizure conditions a contraindication to its use. This risk is exacerbated when bupropion is combined with other drugs or substances that lower the seizure threshold, such as cocaine, or in clinical situations that would increase the risk of a seizure such as abrupt alcohol or benzodiazepine withdrawal. As norepinephrine has been shown to have anticonvulsant properties, bupropion's inhibitory effects on NET are thought to contribute to its pro-convulsant activity. Bupropion has been shown to increase blood pressure and pose a risk for exacerbation of unmanaged or pre-existing hypertension, however, clinical trials of bupropion in smokers with CVD have not identified an increased incidence of CV events including stroke or heart attack. In clinical trials, the mean increase in systolic blood pressure associated with the use of bupropion was found to be 1.3 mmHg. •Pharmacodynamics (Drug B): Administration of metoprolol in normal subjects is widely reported to produce a dose-dependent reduction on heart rate and cardiac output. This effect is generated due to a decreased cardiac excitability, cardiac output, and myocardial oxygen demand. In the case of arrhythmias, metoprolol produces its effect by reducing the slope of the pacemaker potential as well as suppressing the rate of atrioventricular conduction. The Metoprolol Atherosclerosis Prevention in Hypertensives (MAPHY) trial showed a significant improvement in sudden cardiac death and myocardial infarction when patients were given with metoprolol as compared with diuretics. As well, in clinical trials performed in 1990, metoprolol reduces mortality and re-infarction in 17% of the individuals when administered chronically after an episode of myocardial infarction. •Mechanism of action (Drug A): Bupropion is a norepinephrine/dopamine-reuptake inhibitor (NDRI) that exerts its pharmacological effects by weakly inhibiting the enzymes involved in the uptake of the neurotransmitters norepinephrine and dopamine from the synaptic cleft, therefore prolonging their duration of action within the neuronal synapse and the downstream effects of these neurotransmitters. More specifically, bupropion binds to the norepinephrine transporter (NET) and the dopamine transporter (DAT). Bupropion was originally classified as an "atypical" antidepressant because it does not exert the same effects as the classical antidepressants such as Monoamine Oxidase Inhibitors (MAOIs), Tricyclic Antidepressants (TCAs), or Selective Serotonin Reuptake Inhibitors (SSRIs). While it has comparable effectiveness to typical first-line options for the treatment of depression such as SSRIs, bupropion is a unique option for the treatment of MDD as it lacks any clinically relevant serotonergic effects, typical of other mood medications, or any effects on histamine or adrenaline receptors. Lack of activity at these receptors results in a more tolerable side effect profile; bupropion is less likely to cause sexual side effects, sedation, or weight gain as compared to SSRIs or TCAs, for example. When used as an aid to smoking cessation, bupropion is thought to confer its anti-craving and anti-withdrawal effects by inhibiting dopamine reuptake, which is thought to be involved in the reward pathways associated with nicotine, and through the antagonism of the nicotinic acetylcholinergic receptor (AChR), thereby blunting the effects of nicotine. Furthermore, the stimulatory effects produced by bupropion in the central nervous system are similar to nicotine's effects, making low doses of bupropion a suitable option as a nicotine substitute. When used in combination with naltrexone in the marketed product ContraveⓇ for chronic weight management, the two components are thought to have effects on areas of the brain involved in the regulation of food intake. This includes the hypothalamus, which is involved in appetite regulation, and the mesolimbic dopamine circuit, which is involved in reward pathways. Studies have shown that the combined activity of bupropion and naltrexone increase the firing rate of hypothalamic pro-opiomelanocortin (POMC) neurons and blockade of opioid receptor-mediated POMC auto-inhibition, which are associated with a reduction in food intake and increased energy expenditure. This combination was also found to reduce food intake when injected directly into the ventral tegmental area of the mesolimbic circuit in mice, which is an area associated with the regulation of reward pathways. •Mechanism of action (Drug B): Metoprolol is a beta-1-adrenergic receptor inhibitor specific to cardiac cells with negligible effect on beta-2 receptors. This inhibition decreases cardiac output by producing negative chronotropic and inotropic effects without presenting activity towards membrane stabilization nor intrinsic sympathomimetics. •Absorption (Drug A): Bupropion is currently available in 3 distinct, but bioequivalent formulations: immediate release (IR), sustained-release (SR), and extended-release (XL). Immediate Release Formulation In humans, following oral administration of bupropion hydrochloride tablets, peak plasma bupropion concentrations are usually achieved within 2 hours. IR formulations provide a short duration of action and are therefore generally dosed three times per day. Sustained Release Formulation In humans, following oral administration of bupropion hydrochloride sustained-release tablets (SR), peak plasma concentration (Cmax) of bupropion is usually achieved within 3 hours. SR formulations provide a 12-hour extended release of medication and are therefore generally dosed twice per day. Extended Release Formulation Following single oral administration of bupropion hydrochloride extended-release tablets (XL) to healthy volunteers, the median time to peak plasma concentrations for bupropion was approximately 5 hours. The presence of food did not affect the peak concentration or area under the curve of bupropion. XL formulations provide a 24-hour extended release of medication and are therefore generally dosed once per day/ In a trial comparing chronic dosing with bupropion hydrochloride extended-release tablets (SR) 150 mg twice daily to bupropion immediate-release formulation 100 mg 3 times daily, the steady state Cmax for bupropion after bupropion hydrochloride sustained-release tablets (SR) administration was approximately 85% of those achieved after bupropion immediate-release formulation administration. Exposure (AUC) to bupropion was equivalent for both formulations. Bioequivalence was also demonstrated for all three major active metabolites (i.e., hydroxybupropion, threohydrobupropion and erythrohydrobupropion) for both Cmax and AUC. Thus, at steady state, bupropion hydrochloride sustained-release tablets (SR) given twice daily, and the immediate-release formulation of bupropion given 3 times daily, are essentially bioequivalent for both bupropion and the 3 quantitatively important metabolites. Furthermore, in a study comparing 14-day dosing with bupropion hydrochloride extended-release tablets (XL), 300 mg once-daily to the immediate-release formulation of bupropion at 100 mg 3 times daily, equivalence was demonstrated for peak plasma concentration and area under the curve for bupropion and the three metabolites (hydroxybupropion, threohydrobupropion, and erythrohydrobupropion). Additionally, in a study comparing 14-day dosing with bupropion hydrochloride extended-release tablets (XL) 300 mg once daily to the sustained-release formulation of bupropion at 150 mg 2 times daily, equivalence was demonstrated for peak plasma concentration and area under the curve for bupropion and the three metabolites. Bupropion hydrochloride extended-release tablets (SR) can be taken with or without food. Bupropion Cmax and AUC were increased by 11% to 35% and 16% to 19%, respectively, when bupropion hydrochloride extended-release tablets (SR) was administered with food to healthy volunteers in three trials. The food effect is not considered clinically significant. Following a single-dose administration of bupropion hydrochloride extended-release tablets (SR) in humans, Cmax of bupropion's metabolite hydroxybupropion occurs approximately 6 hours post-dose and is approximately 10 times the peak level of the parent drug at steady state. The elimination half-life of hydroxybupropion is approximately 20 (±5) hours and its AUC at steady state is about 17 times that of bupropion. The times to peak concentrations for the erythrohydrobupropion and threohydrobupropion metabolites are similar to that of the hydroxybupropion metabolite. However, their elimination half-lives are longer, 33(±10) and 37 (±13) hours, respectively, and steady-state AUCs are 1.5 and 7 times that of bupropion, respectively. •Absorption (Drug B): When metoprolol is administered orally, it is almost completely absorbed in the gastrointestinal tract. The maximum serum concentration is achieved 20 min after intravenous administration and 1-2 hours after oral administration. The bioavailability of metoprolol is of 100% when administered intravenously and when administered orally it presents about 50% for the tartrate derivative and 40% for the succinate derivative. The absorption of metoprolol in the form of the tartrate derivative is increased by the concomitant administration of food. •Volume of distribution (Drug A): No volume of distribution available •Volume of distribution (Drug B): The reported volume of distribution of metoprolol is 4.2 L/kg. Due to the characteristics of metoprolol, this molecule is able to cross the blood-brain barrier and even 78% of the administered drug can be found in cerebrospinal fluid. •Protein binding (Drug A): In vitro tests show that bupropion is 84% bound to human plasma proteins at concentrations up to 200 mcg per mL. The extent of protein binding of the hydroxybupropion metabolite is similar to that for bupropion, whereas the extent of protein binding of the threohydrobupropion metabolite is about half that seen with bupropion. •Protein binding (Drug B): Metoprolol is not highly bound to plasma proteins and only about 11% of the administered dose is found bound. It is mainly bound to serum albumin. •Metabolism (Drug A): Bupropion is extensively metabolized in humans. Three metabolites are active: hydroxybupropion, which is formed via hydroxylation of the tert-butyl group of bupropion, and the amino-alcohol isomers, threohydrobupropion and erythrohydrobupropion, which are formed via reduction of the carbonyl group. In vitro findings suggest that CYP2B6 is the principal isoenzyme involved in the formation of hydroxybupropion, while cytochrome P450 enzymes are not involved in the formation of threohydrobupropion. Hydroxybupropion has been shown to have the same affinity as bupropion for the norepinephrine transporter (NET) but approximately 50% of its antidepressant activity despite reaching concentrations of ~10-fold higher than that of the parent drug. Oxidation of the bupropion side chain results in the formation of a glycine conjugate of meta-chlorobenzoic acid, which is then excreted as the major urinary metabolite. The potency and toxicity of the metabolites relative to bupropion have not been fully characterized. However, it has been demonstrated in an antidepressant screening test in mice that hydroxybupropion is one-half as potent as bupropion, while threohydrobupropion and erythrohydrobupropion are 5-fold less potent than bupropion. This may be of clinical importance because the plasma concentrations of the metabolites are as high as or higher than those of bupropion. Bupropion and its metabolites exhibit linear kinetics following chronic administration of 300 to 450 mg per day. •Metabolism (Drug B): Metoprolol goes through significant first-pass hepatic metabolism which covers around 50% of the administered dose. The metabolism of metoprolol is mainly driven by the activity of CYP2D6 and to a lesser extent due to the activity of CYP3A4. The metabolism of metoprolol is mainly represented by reactions of hydroxylation and O-demethylation. •Route of elimination (Drug A): Bupropion is extensively metabolized in humans. Oxidation of the bupropion side chain results in the formation of a glycine conjugate of metachlorobenzoic acid, which is then excreted as the major urinary metabolite. Following oral administration of 200 mg of 14C-bupropion in humans, 87% and 10% of the radioactive dose were recovered in the urine and feces, respectively. However, the fraction of the oral dose of bupropion excreted unchanged was only 0.5%, a finding consistent with the extensive metabolism of bupropion. •Route of elimination (Drug B): Metoprolol is mainly excreted via the kidneys. From the eliminated dose, less than 5% is recovered unchanged. •Half-life (Drug A): 24 hours •Half-life (Drug B): The immediate release formulations of metoprolol present a half-life of about 3-7 hours. •Clearance (Drug A): No clearance available •Clearance (Drug B): The reported clearance rate on patients with normal kidney function is 0.8 L/min. In cirrhotic patients, the clearance rate changes to 0.61 L/min. •Toxicity (Drug A): Symptoms of overdose include seizures, hallucinations, loss of consciousness, tachycardia, and cardiac arrest. •Toxicity (Drug B): Oral administration of metoprolol to rats presents an LD50 in the range of 3090 to 4670 mg/kg. Cases of overdose have reported bradycardia, hypotension, bronchospasm, and cardiac failure. In the case of an overdose, gastric lavage is recommended followed by specific treatment according to symptoms. Metoprolol is not reported to be carcinogenic nor mutagenic nor to impair fertility. The only event registered is the increase of macrophages in pulmonary alveoli and slight biliary hyperplasia. When metoprolol was given for long periods of time on the highest dose, there was evidence of small benign lung tumors. •Brand Names (Drug A): Aplenzin, Auvelity, Budeprion, Contrave, Forfivo, Wellbutrin, Zyban •Brand Names (Drug B): Kapspargo, Lopressor, Lopressor Hct, Toprol •Synonyms (Drug A): No synonyms listed •Synonyms (Drug B): (RS)-Metoprolol DL-metoprolol Metoprolol •Summary (Drug A): Bupropion is a norepinephrine and dopamine reuptake inhibitor used in the treatment of major depressive disorder (MDD), seasonal affective disorder (SAD), and as an aid to smoking cessation. •Summary (Drug B): Metoprolol is a beta-blocker used in the treatment of hypertension and angina, and used to reduce mortality due to myocardial infarction.

The subject drug is a strong CYP2D6 inhibitor and the affected drug is metabolized by CYP2D6. Concomitant administration may decrease the metabolism of the affected drug, which could increase serum concentrations as well as the risk and severity of adverse effects. The severity of the interaction is major.

Question: Does Bupropion and Metoprolol interact? Information: •Drug A: Bupropion •Drug B: Metoprolol •Severity: MAJOR •Description: The metabolism of Metoprolol can be decreased when combined with Bupropion. •Extended Description: The subject drug is a strong CYP2D6 inhibitor and the affected drug is metabolized by CYP2D6. Concomitant administration may decrease the metabolism of the affected drug, which could increase serum concentrations as well as the risk and severity of adverse effects. •Indication (Drug A): Bupropion is indicated for the treatment of major depressive disorder (MDD), seasonal affective disorder (SAD), and as an aid to smoking cessation. When used in combination with naltrexone as the marketed product ContraveⓇ, bupropion is indicated as an adjunct to a reduced-calorie diet and increased physical activity for chronic weight management in adults with an initial body mass index (BMI) of: 30 kg/m^2 or greater (obese) or 27 kg/m^2 or greater (overweight) in the presence of at least one weight-related comorbid condition (e.g., hypertension, type 2 diabetes mellitus, or dyslipidemia). Bupropion is also used off-label as a first-line treatment in patients with ADHD and comorbid bipolar disorder when used as an adjunct to mood stabilizers. •Indication (Drug B): Metoprolol is indicated for the treatment of angina, heart failure, myocardial infarction, atrial fibrillation, atrial flutter and hypertension. Some off-label uses of metoprolol include supraventricular tachycardia and thyroid storm. All the indications of metoprolol are part of cardiovascular diseases. These conditions correspond to a number of diseases that involve the function of the heart and blood vessels. The underlying causes of these conditions are variable and can be due to genetic disposition, lifestyle decisions such as smoking, obesity, diet, and lack of exercise, and comorbidity with other conditions such as diabetes. The cardiovascular diseases are the leading cause of death on a global scale. •Pharmacodynamics (Drug A): Bupropion is chemically unrelated to tricyclic, tetracyclic, selective serotonin re-uptake inhibitors, or other known antidepressant agents. Compared to classical tricyclic antidepressants, Bupropion is a relatively weak inhibitor of the neuronal uptake of norepinephrine and dopamine. In addition, Bupropion does not inhibit monoamine oxidase. Bupropion has been found to be essentially inactive at the serotonin transporter (SERT)(IC50 >10 000 nM), however both bupropion and its primary metabolite hydroxybupropion have been found to block the function of cation-selective serotonin type 3A receptors (5-HT3ARs). Bupropion produces dose-related central nervous system (CNS) stimulant effects in animals, as evidenced by increased locomotor activity, increased rates of responding in various schedule-controlled operant behaviour tasks, and, at high doses, induction of mild stereotyped behaviour. Due to these stimulant effects and selective activity at dopamine and norepinephrine receptors, bupropion has been identified as having an abuse potential. Bupropion has a similar structure to the controlled substance Cathinone, and has been identified as having mild amphetamine-like activity, particularly when inhaled or injected. Bupropion is also known to lower the seizure threshold, making any pre-existing seizure conditions a contraindication to its use. This risk is exacerbated when bupropion is combined with other drugs or substances that lower the seizure threshold, such as cocaine, or in clinical situations that would increase the risk of a seizure such as abrupt alcohol or benzodiazepine withdrawal. As norepinephrine has been shown to have anticonvulsant properties, bupropion's inhibitory effects on NET are thought to contribute to its pro-convulsant activity. Bupropion has been shown to increase blood pressure and pose a risk for exacerbation of unmanaged or pre-existing hypertension, however, clinical trials of bupropion in smokers with CVD have not identified an increased incidence of CV events including stroke or heart attack. In clinical trials, the mean increase in systolic blood pressure associated with the use of bupropion was found to be 1.3 mmHg. •Pharmacodynamics (Drug B): Administration of metoprolol in normal subjects is widely reported to produce a dose-dependent reduction on heart rate and cardiac output. This effect is generated due to a decreased cardiac excitability, cardiac output, and myocardial oxygen demand. In the case of arrhythmias, metoprolol produces its effect by reducing the slope of the pacemaker potential as well as suppressing the rate of atrioventricular conduction. The Metoprolol Atherosclerosis Prevention in Hypertensives (MAPHY) trial showed a significant improvement in sudden cardiac death and myocardial infarction when patients were given with metoprolol as compared with diuretics. As well, in clinical trials performed in 1990, metoprolol reduces mortality and re-infarction in 17% of the individuals when administered chronically after an episode of myocardial infarction. •Mechanism of action (Drug A): Bupropion is a norepinephrine/dopamine-reuptake inhibitor (NDRI) that exerts its pharmacological effects by weakly inhibiting the enzymes involved in the uptake of the neurotransmitters norepinephrine and dopamine from the synaptic cleft, therefore prolonging their duration of action within the neuronal synapse and the downstream effects of these neurotransmitters. More specifically, bupropion binds to the norepinephrine transporter (NET) and the dopamine transporter (DAT). Bupropion was originally classified as an "atypical" antidepressant because it does not exert the same effects as the classical antidepressants such as Monoamine Oxidase Inhibitors (MAOIs), Tricyclic Antidepressants (TCAs), or Selective Serotonin Reuptake Inhibitors (SSRIs). While it has comparable effectiveness to typical first-line options for the treatment of depression such as SSRIs, bupropion is a unique option for the treatment of MDD as it lacks any clinically relevant serotonergic effects, typical of other mood medications, or any effects on histamine or adrenaline receptors. Lack of activity at these receptors results in a more tolerable side effect profile; bupropion is less likely to cause sexual side effects, sedation, or weight gain as compared to SSRIs or TCAs, for example. When used as an aid to smoking cessation, bupropion is thought to confer its anti-craving and anti-withdrawal effects by inhibiting dopamine reuptake, which is thought to be involved in the reward pathways associated with nicotine, and through the antagonism of the nicotinic acetylcholinergic receptor (AChR), thereby blunting the effects of nicotine. Furthermore, the stimulatory effects produced by bupropion in the central nervous system are similar to nicotine's effects, making low doses of bupropion a suitable option as a nicotine substitute. When used in combination with naltrexone in the marketed product ContraveⓇ for chronic weight management, the two components are thought to have effects on areas of the brain involved in the regulation of food intake. This includes the hypothalamus, which is involved in appetite regulation, and the mesolimbic dopamine circuit, which is involved in reward pathways. Studies have shown that the combined activity of bupropion and naltrexone increase the firing rate of hypothalamic pro-opiomelanocortin (POMC) neurons and blockade of opioid receptor-mediated POMC auto-inhibition, which are associated with a reduction in food intake and increased energy expenditure. This combination was also found to reduce food intake when injected directly into the ventral tegmental area of the mesolimbic circuit in mice, which is an area associated with the regulation of reward pathways. •Mechanism of action (Drug B): Metoprolol is a beta-1-adrenergic receptor inhibitor specific to cardiac cells with negligible effect on beta-2 receptors. This inhibition decreases cardiac output by producing negative chronotropic and inotropic effects without presenting activity towards membrane stabilization nor intrinsic sympathomimetics. •Absorption (Drug A): Bupropion is currently available in 3 distinct, but bioequivalent formulations: immediate release (IR), sustained-release (SR), and extended-release (XL). Immediate Release Formulation In humans, following oral administration of bupropion hydrochloride tablets, peak plasma bupropion concentrations are usually achieved within 2 hours. IR formulations provide a short duration of action and are therefore generally dosed three times per day. Sustained Release Formulation In humans, following oral administration of bupropion hydrochloride sustained-release tablets (SR), peak plasma concentration (Cmax) of bupropion is usually achieved within 3 hours. SR formulations provide a 12-hour extended release of medication and are therefore generally dosed twice per day. Extended Release Formulation Following single oral administration of bupropion hydrochloride extended-release tablets (XL) to healthy volunteers, the median time to peak plasma concentrations for bupropion was approximately 5 hours. The presence of food did not affect the peak concentration or area under the curve of bupropion. XL formulations provide a 24-hour extended release of medication and are therefore generally dosed once per day/ In a trial comparing chronic dosing with bupropion hydrochloride extended-release tablets (SR) 150 mg twice daily to bupropion immediate-release formulation 100 mg 3 times daily, the steady state Cmax for bupropion after bupropion hydrochloride sustained-release tablets (SR) administration was approximately 85% of those achieved after bupropion immediate-release formulation administration. Exposure (AUC) to bupropion was equivalent for both formulations. Bioequivalence was also demonstrated for all three major active metabolites (i.e., hydroxybupropion, threohydrobupropion and erythrohydrobupropion) for both Cmax and AUC. Thus, at steady state, bupropion hydrochloride sustained-release tablets (SR) given twice daily, and the immediate-release formulation of bupropion given 3 times daily, are essentially bioequivalent for both bupropion and the 3 quantitatively important metabolites. Furthermore, in a study comparing 14-day dosing with bupropion hydrochloride extended-release tablets (XL), 300 mg once-daily to the immediate-release formulation of bupropion at 100 mg 3 times daily, equivalence was demonstrated for peak plasma concentration and area under the curve for bupropion and the three metabolites (hydroxybupropion, threohydrobupropion, and erythrohydrobupropion). Additionally, in a study comparing 14-day dosing with bupropion hydrochloride extended-release tablets (XL) 300 mg once daily to the sustained-release formulation of bupropion at 150 mg 2 times daily, equivalence was demonstrated for peak plasma concentration and area under the curve for bupropion and the three metabolites. Bupropion hydrochloride extended-release tablets (SR) can be taken with or without food. Bupropion Cmax and AUC were increased by 11% to 35% and 16% to 19%, respectively, when bupropion hydrochloride extended-release tablets (SR) was administered with food to healthy volunteers in three trials. The food effect is not considered clinically significant. Following a single-dose administration of bupropion hydrochloride extended-release tablets (SR) in humans, Cmax of bupropion's metabolite hydroxybupropion occurs approximately 6 hours post-dose and is approximately 10 times the peak level of the parent drug at steady state. The elimination half-life of hydroxybupropion is approximately 20 (±5) hours and its AUC at steady state is about 17 times that of bupropion. The times to peak concentrations for the erythrohydrobupropion and threohydrobupropion metabolites are similar to that of the hydroxybupropion metabolite. However, their elimination half-lives are longer, 33(±10) and 37 (±13) hours, respectively, and steady-state AUCs are 1.5 and 7 times that of bupropion, respectively. •Absorption (Drug B): When metoprolol is administered orally, it is almost completely absorbed in the gastrointestinal tract. The maximum serum concentration is achieved 20 min after intravenous administration and 1-2 hours after oral administration. The bioavailability of metoprolol is of 100% when administered intravenously and when administered orally it presents about 50% for the tartrate derivative and 40% for the succinate derivative. The absorption of metoprolol in the form of the tartrate derivative is increased by the concomitant administration of food. •Volume of distribution (Drug A): No volume of distribution available •Volume of distribution (Drug B): The reported volume of distribution of metoprolol is 4.2 L/kg. Due to the characteristics of metoprolol, this molecule is able to cross the blood-brain barrier and even 78% of the administered drug can be found in cerebrospinal fluid. •Protein binding (Drug A): In vitro tests show that bupropion is 84% bound to human plasma proteins at concentrations up to 200 mcg per mL. The extent of protein binding of the hydroxybupropion metabolite is similar to that for bupropion, whereas the extent of protein binding of the threohydrobupropion metabolite is about half that seen with bupropion. •Protein binding (Drug B): Metoprolol is not highly bound to plasma proteins and only about 11% of the administered dose is found bound. It is mainly bound to serum albumin. •Metabolism (Drug A): Bupropion is extensively metabolized in humans. Three metabolites are active: hydroxybupropion, which is formed via hydroxylation of the tert-butyl group of bupropion, and the amino-alcohol isomers, threohydrobupropion and erythrohydrobupropion, which are formed via reduction of the carbonyl group. In vitro findings suggest that CYP2B6 is the principal isoenzyme involved in the formation of hydroxybupropion, while cytochrome P450 enzymes are not involved in the formation of threohydrobupropion. Hydroxybupropion has been shown to have the same affinity as bupropion for the norepinephrine transporter (NET) but approximately 50% of its antidepressant activity despite reaching concentrations of ~10-fold higher than that of the parent drug. Oxidation of the bupropion side chain results in the formation of a glycine conjugate of meta-chlorobenzoic acid, which is then excreted as the major urinary metabolite. The potency and toxicity of the metabolites relative to bupropion have not been fully characterized. However, it has been demonstrated in an antidepressant screening test in mice that hydroxybupropion is one-half as potent as bupropion, while threohydrobupropion and erythrohydrobupropion are 5-fold less potent than bupropion. This may be of clinical importance because the plasma concentrations of the metabolites are as high as or higher than those of bupropion. Bupropion and its metabolites exhibit linear kinetics following chronic administration of 300 to 450 mg per day. •Metabolism (Drug B): Metoprolol goes through significant first-pass hepatic metabolism which covers around 50% of the administered dose. The metabolism of metoprolol is mainly driven by the activity of CYP2D6 and to a lesser extent due to the activity of CYP3A4. The metabolism of metoprolol is mainly represented by reactions of hydroxylation and O-demethylation. •Route of elimination (Drug A): Bupropion is extensively metabolized in humans. Oxidation of the bupropion side chain results in the formation of a glycine conjugate of metachlorobenzoic acid, which is then excreted as the major urinary metabolite. Following oral administration of 200 mg of 14C-bupropion in humans, 87% and 10% of the radioactive dose were recovered in the urine and feces, respectively. However, the fraction of the oral dose of bupropion excreted unchanged was only 0.5%, a finding consistent with the extensive metabolism of bupropion. •Route of elimination (Drug B): Metoprolol is mainly excreted via the kidneys. From the eliminated dose, less than 5% is recovered unchanged. •Half-life (Drug A): 24 hours •Half-life (Drug B): The immediate release formulations of metoprolol present a half-life of about 3-7 hours. •Clearance (Drug A): No clearance available •Clearance (Drug B): The reported clearance rate on patients with normal kidney function is 0.8 L/min. In cirrhotic patients, the clearance rate changes to 0.61 L/min. •Toxicity (Drug A): Symptoms of overdose include seizures, hallucinations, loss of consciousness, tachycardia, and cardiac arrest. •Toxicity (Drug B): Oral administration of metoprolol to rats presents an LD50 in the range of 3090 to 4670 mg/kg. Cases of overdose have reported bradycardia, hypotension, bronchospasm, and cardiac failure. In the case of an overdose, gastric lavage is recommended followed by specific treatment according to symptoms. Metoprolol is not reported to be carcinogenic nor mutagenic nor to impair fertility. The only event registered is the increase of macrophages in pulmonary alveoli and slight biliary hyperplasia. When metoprolol was given for long periods of time on the highest dose, there was evidence of small benign lung tumors. •Brand Names (Drug A): Aplenzin, Auvelity, Budeprion, Contrave, Forfivo, Wellbutrin, Zyban •Brand Names (Drug B): Kapspargo, Lopressor, Lopressor Hct, Toprol •Synonyms (Drug A): No synonyms listed •Synonyms (Drug B): (RS)-Metoprolol DL-metoprolol Metoprolol •Summary (Drug A): Bupropion is a norepinephrine and dopamine reuptake inhibitor used in the treatment of major depressive disorder (MDD), seasonal affective disorder (SAD), and as an aid to smoking cessation. •Summary (Drug B): Metoprolol is a beta-blocker used in the treatment of hypertension and angina, and used to reduce mortality due to myocardial infarction. Output: The subject drug is a strong CYP2D6 inhibitor and the affected drug is metabolized by CYP2D6. Concomitant administration may decrease the metabolism of the affected drug, which could increase serum concentrations as well as the risk and severity of adverse effects. The severity of the interaction is major.

Does Bupropion and Metronidazole interact?

•Drug A: Bupropion •Drug B: Metronidazole •Severity: MODERATE •Description: The risk or severity of seizure can be increased when Bupropion is combined with Metronidazole. •Extended Description: Bupropion carries a dose-dependent risk of seizure1 that may be further exacerbated when combined with other medications that can reduce the seizure threshold (i.e. increase the risk of seizure), such as the affected drug. This risk may be also compounded by patient-specific factors that may increase the risk of seizure such as metabolic disorders and illicit drug use. •Indication (Drug A): Bupropion is indicated for the treatment of major depressive disorder (MDD), seasonal affective disorder (SAD), and as an aid to smoking cessation. When used in combination with naltrexone as the marketed product ContraveⓇ, bupropion is indicated as an adjunct to a reduced-calorie diet and increased physical activity for chronic weight management in adults with an initial body mass index (BMI) of: 30 kg/m^2 or greater (obese) or 27 kg/m^2 or greater (overweight) in the presence of at least one weight-related comorbid condition (e.g., hypertension, type 2 diabetes mellitus, or dyslipidemia). Bupropion is also used off-label as a first-line treatment in patients with ADHD and comorbid bipolar disorder when used as an adjunct to mood stabilizers. •Indication (Drug B): Metronidazole is indicated for the treatment of confirmed trichomoniasis caused by Trichomonas vaginalis (except for in the first trimester of pregnancy) and the patient's sexual partners, bacterial vaginosis, certain types of amebiasis, and various anaerobic infections. The above anaerobic infections may occur on the skin and skin structures, the abdomen, the heart, reproductive organs, central nervous system, and the respiratory system. Some may also be present in the bloodstream in cases of septicemia. Common infections treated by metronidazole are Bacteroides species infections, Clostridium infections, and Fusobacterium infections, as well as Peptococcus and Peptostreptococcus infections. Topical formulations of metronidazole are indicated for the treatment of inflammatory lesions of rosacea. It is also used off-label in the treatment of Crohn's disease, as a prophylactic agent after surgery, and in the treatment of Helicobacter pylori infection. It has also been studied in the prevention of preterm births and to treat periodontal disease. •Pharmacodynamics (Drug A): Bupropion is chemically unrelated to tricyclic, tetracyclic, selective serotonin re-uptake inhibitors, or other known antidepressant agents. Compared to classical tricyclic antidepressants, Bupropion is a relatively weak inhibitor of the neuronal uptake of norepinephrine and dopamine. In addition, Bupropion does not inhibit monoamine oxidase. Bupropion has been found to be essentially inactive at the serotonin transporter (SERT)(IC50 >10 000 nM), however both bupropion and its primary metabolite hydroxybupropion have been found to block the function of cation-selective serotonin type 3A receptors (5-HT3ARs). Bupropion produces dose-related central nervous system (CNS) stimulant effects in animals, as evidenced by increased locomotor activity, increased rates of responding in various schedule-controlled operant behaviour tasks, and, at high doses, induction of mild stereotyped behaviour. Due to these stimulant effects and selective activity at dopamine and norepinephrine receptors, bupropion has been identified as having an abuse potential. Bupropion has a similar structure to the controlled substance Cathinone, and has been identified as having mild amphetamine-like activity, particularly when inhaled or injected. Bupropion is also known to lower the seizure threshold, making any pre-existing seizure conditions a contraindication to its use. This risk is exacerbated when bupropion is combined with other drugs or substances that lower the seizure threshold, such as cocaine, or in clinical situations that would increase the risk of a seizure such as abrupt alcohol or benzodiazepine withdrawal. As norepinephrine has been shown to have anticonvulsant properties, bupropion's inhibitory effects on NET are thought to contribute to its pro-convulsant activity. Bupropion has been shown to increase blood pressure and pose a risk for exacerbation of unmanaged or pre-existing hypertension, however, clinical trials of bupropion in smokers with CVD have not identified an increased incidence of CV events including stroke or heart attack. In clinical trials, the mean increase in systolic blood pressure associated with the use of bupropion was found to be 1.3 mmHg. •Pharmacodynamics (Drug B): Metronidazole treats amebiasis, trichomoniasis, and giardiasis, exerting both antibacterial and antiprotozoal activities. Metronidazole is an effective treatment for some anaerobic bacterial infections. Metronidazole has shown antibacterial activity against the majority of obligate anaerobes, however, during in vitro studies, it does not demonstrate significant action against facultative anaerobes or obligate aerobes. The nitro group reduction of metronidazole by anaerobic organisms is likely responsible for the drug's antimicrobial cytotoxic effects, causing DNA strand damage to microbes. A note on convulsions and neuropathy and carcinogenesis It is important to be aware of the risk of peripheral neuropathy and convulsions associated with metronidazole, especially at higher doses. If convulsions or numbness of an extremity occur, discontinue the drug immediately. Metronidazole has been found to be carcinogenic in mice and rats. The relevance to this effect in humans is unknown. It is advisable to only administer metronidazole when clinically necessary and only for its approved indications. •Mechanism of action (Drug A): Bupropion is a norepinephrine/dopamine-reuptake inhibitor (NDRI) that exerts its pharmacological effects by weakly inhibiting the enzymes involved in the uptake of the neurotransmitters norepinephrine and dopamine from the synaptic cleft, therefore prolonging their duration of action within the neuronal synapse and the downstream effects of these neurotransmitters. More specifically, bupropion binds to the norepinephrine transporter (NET) and the dopamine transporter (DAT). Bupropion was originally classified as an "atypical" antidepressant because it does not exert the same effects as the classical antidepressants such as Monoamine Oxidase Inhibitors (MAOIs), Tricyclic Antidepressants (TCAs), or Selective Serotonin Reuptake Inhibitors (SSRIs). While it has comparable effectiveness to typical first-line options for the treatment of depression such as SSRIs, bupropion is a unique option for the treatment of MDD as it lacks any clinically relevant serotonergic effects, typical of other mood medications, or any effects on histamine or adrenaline receptors. Lack of activity at these receptors results in a more tolerable side effect profile; bupropion is less likely to cause sexual side effects, sedation, or weight gain as compared to SSRIs or TCAs, for example. When used as an aid to smoking cessation, bupropion is thought to confer its anti-craving and anti-withdrawal effects by inhibiting dopamine reuptake, which is thought to be involved in the reward pathways associated with nicotine, and through the antagonism of the nicotinic acetylcholinergic receptor (AChR), thereby blunting the effects of nicotine. Furthermore, the stimulatory effects produced by bupropion in the central nervous system are similar to nicotine's effects, making low doses of bupropion a suitable option as a nicotine substitute. When used in combination with naltrexone in the marketed product ContraveⓇ for chronic weight management, the two components are thought to have effects on areas of the brain involved in the regulation of food intake. This includes the hypothalamus, which is involved in appetite regulation, and the mesolimbic dopamine circuit, which is involved in reward pathways. Studies have shown that the combined activity of bupropion and naltrexone increase the firing rate of hypothalamic pro-opiomelanocortin (POMC) neurons and blockade of opioid receptor-mediated POMC auto-inhibition, which are associated with a reduction in food intake and increased energy expenditure. This combination was also found to reduce food intake when injected directly into the ventral tegmental area of the mesolimbic circuit in mice, which is an area associated with the regulation of reward pathways. •Mechanism of action (Drug B): The exact mechanism of action of metronidazole has not been fully established, however, it is possible that an intermediate in the reduction of metronidazole which is only made by anaerobic bacteria and protozoa, binds deoxyribonucleic acid and electron-transport proteins of organisms, blocking nucleic acid synthesis. After administration, metronidazole enters cells by passive diffusion. Following this, ferredoxin or flavodoxin reduce its nitro group to nitro radicals. The redox potential of the electron transport portions of anaerobic or microaerophilic microorganisms renders metronidazole selective to these organisms, which cause nitro group reduction, leading to the production of toxic metabolites. These include N-(2-hydroxyethyl) oxamic acid and acetamide, which may damage DNA of replicating organisms. •Absorption (Drug A): Bupropion is currently available in 3 distinct, but bioequivalent formulations: immediate release (IR), sustained-release (SR), and extended-release (XL). Immediate Release Formulation In humans, following oral administration of bupropion hydrochloride tablets, peak plasma bupropion concentrations are usually achieved within 2 hours. IR formulations provide a short duration of action and are therefore generally dosed three times per day. Sustained Release Formulation In humans, following oral administration of bupropion hydrochloride sustained-release tablets (SR), peak plasma concentration (Cmax) of bupropion is usually achieved within 3 hours. SR formulations provide a 12-hour extended release of medication and are therefore generally dosed twice per day. Extended Release Formulation Following single oral administration of bupropion hydrochloride extended-release tablets (XL) to healthy volunteers, the median time to peak plasma concentrations for bupropion was approximately 5 hours. The presence of food did not affect the peak concentration or area under the curve of bupropion. XL formulations provide a 24-hour extended release of medication and are therefore generally dosed once per day/ In a trial comparing chronic dosing with bupropion hydrochloride extended-release tablets (SR) 150 mg twice daily to bupropion immediate-release formulation 100 mg 3 times daily, the steady state Cmax for bupropion after bupropion hydrochloride sustained-release tablets (SR) administration was approximately 85% of those achieved after bupropion immediate-release formulation administration. Exposure (AUC) to bupropion was equivalent for both formulations. Bioequivalence was also demonstrated for all three major active metabolites (i.e., hydroxybupropion, threohydrobupropion and erythrohydrobupropion) for both Cmax and AUC. Thus, at steady state, bupropion hydrochloride sustained-release tablets (SR) given twice daily, and the immediate-release formulation of bupropion given 3 times daily, are essentially bioequivalent for both bupropion and the 3 quantitatively important metabolites. Furthermore, in a study comparing 14-day dosing with bupropion hydrochloride extended-release tablets (XL), 300 mg once-daily to the immediate-release formulation of bupropion at 100 mg 3 times daily, equivalence was demonstrated for peak plasma concentration and area under the curve for bupropion and the three metabolites (hydroxybupropion, threohydrobupropion, and erythrohydrobupropion). Additionally, in a study comparing 14-day dosing with bupropion hydrochloride extended-release tablets (XL) 300 mg once daily to the sustained-release formulation of bupropion at 150 mg 2 times daily, equivalence was demonstrated for peak plasma concentration and area under the curve for bupropion and the three metabolites. Bupropion hydrochloride extended-release tablets (SR) can be taken with or without food. Bupropion Cmax and AUC were increased by 11% to 35% and 16% to 19%, respectively, when bupropion hydrochloride extended-release tablets (SR) was administered with food to healthy volunteers in three trials. The food effect is not considered clinically significant. Following a single-dose administration of bupropion hydrochloride extended-release tablets (SR) in humans, Cmax of bupropion's metabolite hydroxybupropion occurs approximately 6 hours post-dose and is approximately 10 times the peak level of the parent drug at steady state. The elimination half-life of hydroxybupropion is approximately 20 (±5) hours and its AUC at steady state is about 17 times that of bupropion. The times to peak concentrations for the erythrohydrobupropion and threohydrobupropion metabolites are similar to that of the hydroxybupropion metabolite. However, their elimination half-lives are longer, 33(±10) and 37 (±13) hours, respectively, and steady-state AUCs are 1.5 and 7 times that of bupropion, respectively. •Absorption (Drug B): After the intravenous infusion of a 1.5g dose, peak concentration was reached within 1 hour and was peak level of 30-40 mg/L. When a multiple-dose regimen of 500mg three times a day administered intravenously, steady-state concentrations were achieved within about 3 days and peak concentration was measured at 26 mg/L. When administered orally in the tablet form, metronidazole is absorbed entirely absorbed, showing a bioavailability of greater than 90%. One resource indicates that Cmax after a single oral dose of 500mg metronidazole ranges from 8 to 13 mg/L, with a Tmax of 25 minutes to 4 hours. The AUC following a single 500mg oral dose of metronidazole was 122 ± 10.3 mg/L • h. A note on the absorption of topical preparations Insignificant percutaneous absorption of metronidazole occurs after the application of 1% metronidazole cream topically. Healthy volunteers applied one 100 mg dose of 14C-labelled metronidazole 2% cream to unbroken skin. After 12 hours, metronidazole was not detected in the plasma. Approximately 0.1% to 1% of the administered metronidazole was measured in the urine and feces. •Volume of distribution (Drug A): No volume of distribution available •Volume of distribution (Drug B): Metronidazole is widely distributed throughout the body and various body fluids. They include the bile, saliva, breastmilk, cerebrospinal fluid, and the placenta. Steady-state volume distribution of metronidazole in adults ranges from 0.51 to 1.1 L/kg. It attains 60 to 100% of plasma concentrations in various tissues, such as the central nervous system, however, is not measured in high concentrations in the placental tissue. •Protein binding (Drug A): In vitro tests show that bupropion is 84% bound to human plasma proteins at concentrations up to 200 mcg per mL. The extent of protein binding of the hydroxybupropion metabolite is similar to that for bupropion, whereas the extent of protein binding of the threohydrobupropion metabolite is about half that seen with bupropion. •Protein binding (Drug B): Metronidazole is less than 20% bound to plasma proteins. •Metabolism (Drug A): Bupropion is extensively metabolized in humans. Three metabolites are active: hydroxybupropion, which is formed via hydroxylation of the tert-butyl group of bupropion, and the amino-alcohol isomers, threohydrobupropion and erythrohydrobupropion, which are formed via reduction of the carbonyl group. In vitro findings suggest that CYP2B6 is the principal isoenzyme involved in the formation of hydroxybupropion, while cytochrome P450 enzymes are not involved in the formation of threohydrobupropion. Hydroxybupropion has been shown to have the same affinity as bupropion for the norepinephrine transporter (NET) but approximately 50% of its antidepressant activity despite reaching concentrations of ~10-fold higher than that of the parent drug. Oxidation of the bupropion side chain results in the formation of a glycine conjugate of meta-chlorobenzoic acid, which is then excreted as the major urinary metabolite. The potency and toxicity of the metabolites relative to bupropion have not been fully characterized. However, it has been demonstrated in an antidepressant screening test in mice that hydroxybupropion is one-half as potent as bupropion, while threohydrobupropion and erythrohydrobupropion are 5-fold less potent than bupropion. This may be of clinical importance because the plasma concentrations of the metabolites are as high as or higher than those of bupropion. Bupropion and its metabolites exhibit linear kinetics following chronic administration of 300 to 450 mg per day. •Metabolism (Drug B): Metronidazole undergoes hepatic metabolism via hydroxylation, oxidation, and glucuronidation. The metabolism of metronidazole yields 5 metabolites. The hydroxy metabolite, 1-(2-hydroxy-ethyl)-2-hydroxy methyl-5-nitroimidazole, is considered the major active metabolite. Unchanged metronidazole is found in the plasma along with small amounts of its 2- hydroxymethyl metabolite. Several metabolites of metronidazole are found in the urine. They are primarily a product of side-chain oxidation in addition to glucuronide conjugation. Only 20% of the dose found in the urine is accounted for by unchanged metronidazole. The two main oxidative metabolites of metronidazole are hydroxy and acetic acid metabolites. •Route of elimination (Drug A): Bupropion is extensively metabolized in humans. Oxidation of the bupropion side chain results in the formation of a glycine conjugate of metachlorobenzoic acid, which is then excreted as the major urinary metabolite. Following oral administration of 200 mg of 14C-bupropion in humans, 87% and 10% of the radioactive dose were recovered in the urine and feces, respectively. However, the fraction of the oral dose of bupropion excreted unchanged was only 0.5%, a finding consistent with the extensive metabolism of bupropion. •Route of elimination (Drug B): Metronidazole and metabolites are 60 to 80% eliminated in the urine, and 6-15% excreted in the feces. •Half-life (Drug A): 24 hours •Half-life (Drug B): The elimination half-life of metronidazole is 7.3 ± 1.0 after a single 500mg IV dose in healthy subjects. Another resource indicates that the elimination half-life for metronidazole ranges from 6 to 10 hours. •Clearance (Drug A): No clearance available •Clearance (Drug B): Dose adjustments may be required in patients with hepatic impairment, as clearance is impaired in these patients. The clearance of metronidazole in the kidneys is estimated at 10 mL/min/1.73 m2. The total clearance from serum is about 2.1 to 6.4 L/h/kg. •Toxicity (Drug A): Symptoms of overdose include seizures, hallucinations, loss of consciousness, tachycardia, and cardiac arrest. •Toxicity (Drug B): LD50 information The oral LD50 of metronidazole in rats is 5000 mg/kg Overdose information Adverse effects that may be exaggerated with an overdose include peripheral neuropathy, central nervous system toxicity, seizures, disulfiram-like effect (if combined with alcohol) dark urine, a metallic taste in the mouth, nausea, epigastric discomfort, and vertigo, in addition to neutropenia. There is no specific antidote for metronidazole overdose. Symptomatic and supportive treatment should be employed in addition to the administration of activated charcoal to remove the unabsorbed drug from the gastrointestinal tract. In addition to the above measures, contact the local poison control center for updated information on the management of a metronidazole overdose. •Brand Names (Drug A): Aplenzin, Auvelity, Budeprion, Contrave, Forfivo, Wellbutrin, Zyban •Brand Names (Drug B): Flagyl, Flagystatin, Likmez, Metrocream, Metrogel, Metrolotion, Nidagel, Noritate, Nuvessa, Pylera, Rosadan, Vandazole •Synonyms (Drug A): No synonyms listed •Synonyms (Drug B): Metronidazol Métronidazole Metronidazole Metronidazolum •Summary (Drug A): Bupropion is a norepinephrine and dopamine reuptake inhibitor used in the treatment of major depressive disorder (MDD), seasonal affective disorder (SAD), and as an aid to smoking cessation. •Summary (Drug B): Metronidazole is a nitroimidazole used to treat trichomoniasis, amebiasis, inflammatory lesions of rosacea, and bacterial infections, as well as prevent postoperative infections.

Bupropion carries a dose-dependent risk of seizure1 that may be further exacerbated when combined with other medications that can reduce the seizure threshold (i.e. increase the risk of seizure), such as the affected drug. This risk may be also compounded by patient-specific factors that may increase the risk of seizure such as metabolic disorders and illicit drug use. The severity of the interaction is moderate.

Question: Does Bupropion and Metronidazole interact? Information: •Drug A: Bupropion •Drug B: Metronidazole •Severity: MODERATE •Description: The risk or severity of seizure can be increased when Bupropion is combined with Metronidazole. •Extended Description: Bupropion carries a dose-dependent risk of seizure1 that may be further exacerbated when combined with other medications that can reduce the seizure threshold (i.e. increase the risk of seizure), such as the affected drug. This risk may be also compounded by patient-specific factors that may increase the risk of seizure such as metabolic disorders and illicit drug use. •Indication (Drug A): Bupropion is indicated for the treatment of major depressive disorder (MDD), seasonal affective disorder (SAD), and as an aid to smoking cessation. When used in combination with naltrexone as the marketed product ContraveⓇ, bupropion is indicated as an adjunct to a reduced-calorie diet and increased physical activity for chronic weight management in adults with an initial body mass index (BMI) of: 30 kg/m^2 or greater (obese) or 27 kg/m^2 or greater (overweight) in the presence of at least one weight-related comorbid condition (e.g., hypertension, type 2 diabetes mellitus, or dyslipidemia). Bupropion is also used off-label as a first-line treatment in patients with ADHD and comorbid bipolar disorder when used as an adjunct to mood stabilizers. •Indication (Drug B): Metronidazole is indicated for the treatment of confirmed trichomoniasis caused by Trichomonas vaginalis (except for in the first trimester of pregnancy) and the patient's sexual partners, bacterial vaginosis, certain types of amebiasis, and various anaerobic infections. The above anaerobic infections may occur on the skin and skin structures, the abdomen, the heart, reproductive organs, central nervous system, and the respiratory system. Some may also be present in the bloodstream in cases of septicemia. Common infections treated by metronidazole are Bacteroides species infections, Clostridium infections, and Fusobacterium infections, as well as Peptococcus and Peptostreptococcus infections. Topical formulations of metronidazole are indicated for the treatment of inflammatory lesions of rosacea. It is also used off-label in the treatment of Crohn's disease, as a prophylactic agent after surgery, and in the treatment of Helicobacter pylori infection. It has also been studied in the prevention of preterm births and to treat periodontal disease. •Pharmacodynamics (Drug A): Bupropion is chemically unrelated to tricyclic, tetracyclic, selective serotonin re-uptake inhibitors, or other known antidepressant agents. Compared to classical tricyclic antidepressants, Bupropion is a relatively weak inhibitor of the neuronal uptake of norepinephrine and dopamine. In addition, Bupropion does not inhibit monoamine oxidase. Bupropion has been found to be essentially inactive at the serotonin transporter (SERT)(IC50 >10 000 nM), however both bupropion and its primary metabolite hydroxybupropion have been found to block the function of cation-selective serotonin type 3A receptors (5-HT3ARs). Bupropion produces dose-related central nervous system (CNS) stimulant effects in animals, as evidenced by increased locomotor activity, increased rates of responding in various schedule-controlled operant behaviour tasks, and, at high doses, induction of mild stereotyped behaviour. Due to these stimulant effects and selective activity at dopamine and norepinephrine receptors, bupropion has been identified as having an abuse potential. Bupropion has a similar structure to the controlled substance Cathinone, and has been identified as having mild amphetamine-like activity, particularly when inhaled or injected. Bupropion is also known to lower the seizure threshold, making any pre-existing seizure conditions a contraindication to its use. This risk is exacerbated when bupropion is combined with other drugs or substances that lower the seizure threshold, such as cocaine, or in clinical situations that would increase the risk of a seizure such as abrupt alcohol or benzodiazepine withdrawal. As norepinephrine has been shown to have anticonvulsant properties, bupropion's inhibitory effects on NET are thought to contribute to its pro-convulsant activity. Bupropion has been shown to increase blood pressure and pose a risk for exacerbation of unmanaged or pre-existing hypertension, however, clinical trials of bupropion in smokers with CVD have not identified an increased incidence of CV events including stroke or heart attack. In clinical trials, the mean increase in systolic blood pressure associated with the use of bupropion was found to be 1.3 mmHg. •Pharmacodynamics (Drug B): Metronidazole treats amebiasis, trichomoniasis, and giardiasis, exerting both antibacterial and antiprotozoal activities. Metronidazole is an effective treatment for some anaerobic bacterial infections. Metronidazole has shown antibacterial activity against the majority of obligate anaerobes, however, during in vitro studies, it does not demonstrate significant action against facultative anaerobes or obligate aerobes. The nitro group reduction of metronidazole by anaerobic organisms is likely responsible for the drug's antimicrobial cytotoxic effects, causing DNA strand damage to microbes. A note on convulsions and neuropathy and carcinogenesis It is important to be aware of the risk of peripheral neuropathy and convulsions associated with metronidazole, especially at higher doses. If convulsions or numbness of an extremity occur, discontinue the drug immediately. Metronidazole has been found to be carcinogenic in mice and rats. The relevance to this effect in humans is unknown. It is advisable to only administer metronidazole when clinically necessary and only for its approved indications. •Mechanism of action (Drug A): Bupropion is a norepinephrine/dopamine-reuptake inhibitor (NDRI) that exerts its pharmacological effects by weakly inhibiting the enzymes involved in the uptake of the neurotransmitters norepinephrine and dopamine from the synaptic cleft, therefore prolonging their duration of action within the neuronal synapse and the downstream effects of these neurotransmitters. More specifically, bupropion binds to the norepinephrine transporter (NET) and the dopamine transporter (DAT). Bupropion was originally classified as an "atypical" antidepressant because it does not exert the same effects as the classical antidepressants such as Monoamine Oxidase Inhibitors (MAOIs), Tricyclic Antidepressants (TCAs), or Selective Serotonin Reuptake Inhibitors (SSRIs). While it has comparable effectiveness to typical first-line options for the treatment of depression such as SSRIs, bupropion is a unique option for the treatment of MDD as it lacks any clinically relevant serotonergic effects, typical of other mood medications, or any effects on histamine or adrenaline receptors. Lack of activity at these receptors results in a more tolerable side effect profile; bupropion is less likely to cause sexual side effects, sedation, or weight gain as compared to SSRIs or TCAs, for example. When used as an aid to smoking cessation, bupropion is thought to confer its anti-craving and anti-withdrawal effects by inhibiting dopamine reuptake, which is thought to be involved in the reward pathways associated with nicotine, and through the antagonism of the nicotinic acetylcholinergic receptor (AChR), thereby blunting the effects of nicotine. Furthermore, the stimulatory effects produced by bupropion in the central nervous system are similar to nicotine's effects, making low doses of bupropion a suitable option as a nicotine substitute. When used in combination with naltrexone in the marketed product ContraveⓇ for chronic weight management, the two components are thought to have effects on areas of the brain involved in the regulation of food intake. This includes the hypothalamus, which is involved in appetite regulation, and the mesolimbic dopamine circuit, which is involved in reward pathways. Studies have shown that the combined activity of bupropion and naltrexone increase the firing rate of hypothalamic pro-opiomelanocortin (POMC) neurons and blockade of opioid receptor-mediated POMC auto-inhibition, which are associated with a reduction in food intake and increased energy expenditure. This combination was also found to reduce food intake when injected directly into the ventral tegmental area of the mesolimbic circuit in mice, which is an area associated with the regulation of reward pathways. •Mechanism of action (Drug B): The exact mechanism of action of metronidazole has not been fully established, however, it is possible that an intermediate in the reduction of metronidazole which is only made by anaerobic bacteria and protozoa, binds deoxyribonucleic acid and electron-transport proteins of organisms, blocking nucleic acid synthesis. After administration, metronidazole enters cells by passive diffusion. Following this, ferredoxin or flavodoxin reduce its nitro group to nitro radicals. The redox potential of the electron transport portions of anaerobic or microaerophilic microorganisms renders metronidazole selective to these organisms, which cause nitro group reduction, leading to the production of toxic metabolites. These include N-(2-hydroxyethyl) oxamic acid and acetamide, which may damage DNA of replicating organisms. •Absorption (Drug A): Bupropion is currently available in 3 distinct, but bioequivalent formulations: immediate release (IR), sustained-release (SR), and extended-release (XL). Immediate Release Formulation In humans, following oral administration of bupropion hydrochloride tablets, peak plasma bupropion concentrations are usually achieved within 2 hours. IR formulations provide a short duration of action and are therefore generally dosed three times per day. Sustained Release Formulation In humans, following oral administration of bupropion hydrochloride sustained-release tablets (SR), peak plasma concentration (Cmax) of bupropion is usually achieved within 3 hours. SR formulations provide a 12-hour extended release of medication and are therefore generally dosed twice per day. Extended Release Formulation Following single oral administration of bupropion hydrochloride extended-release tablets (XL) to healthy volunteers, the median time to peak plasma concentrations for bupropion was approximately 5 hours. The presence of food did not affect the peak concentration or area under the curve of bupropion. XL formulations provide a 24-hour extended release of medication and are therefore generally dosed once per day/ In a trial comparing chronic dosing with bupropion hydrochloride extended-release tablets (SR) 150 mg twice daily to bupropion immediate-release formulation 100 mg 3 times daily, the steady state Cmax for bupropion after bupropion hydrochloride sustained-release tablets (SR) administration was approximately 85% of those achieved after bupropion immediate-release formulation administration. Exposure (AUC) to bupropion was equivalent for both formulations. Bioequivalence was also demonstrated for all three major active metabolites (i.e., hydroxybupropion, threohydrobupropion and erythrohydrobupropion) for both Cmax and AUC. Thus, at steady state, bupropion hydrochloride sustained-release tablets (SR) given twice daily, and the immediate-release formulation of bupropion given 3 times daily, are essentially bioequivalent for both bupropion and the 3 quantitatively important metabolites. Furthermore, in a study comparing 14-day dosing with bupropion hydrochloride extended-release tablets (XL), 300 mg once-daily to the immediate-release formulation of bupropion at 100 mg 3 times daily, equivalence was demonstrated for peak plasma concentration and area under the curve for bupropion and the three metabolites (hydroxybupropion, threohydrobupropion, and erythrohydrobupropion). Additionally, in a study comparing 14-day dosing with bupropion hydrochloride extended-release tablets (XL) 300 mg once daily to the sustained-release formulation of bupropion at 150 mg 2 times daily, equivalence was demonstrated for peak plasma concentration and area under the curve for bupropion and the three metabolites. Bupropion hydrochloride extended-release tablets (SR) can be taken with or without food. Bupropion Cmax and AUC were increased by 11% to 35% and 16% to 19%, respectively, when bupropion hydrochloride extended-release tablets (SR) was administered with food to healthy volunteers in three trials. The food effect is not considered clinically significant. Following a single-dose administration of bupropion hydrochloride extended-release tablets (SR) in humans, Cmax of bupropion's metabolite hydroxybupropion occurs approximately 6 hours post-dose and is approximately 10 times the peak level of the parent drug at steady state. The elimination half-life of hydroxybupropion is approximately 20 (±5) hours and its AUC at steady state is about 17 times that of bupropion. The times to peak concentrations for the erythrohydrobupropion and threohydrobupropion metabolites are similar to that of the hydroxybupropion metabolite. However, their elimination half-lives are longer, 33(±10) and 37 (±13) hours, respectively, and steady-state AUCs are 1.5 and 7 times that of bupropion, respectively. •Absorption (Drug B): After the intravenous infusion of a 1.5g dose, peak concentration was reached within 1 hour and was peak level of 30-40 mg/L. When a multiple-dose regimen of 500mg three times a day administered intravenously, steady-state concentrations were achieved within about 3 days and peak concentration was measured at 26 mg/L. When administered orally in the tablet form, metronidazole is absorbed entirely absorbed, showing a bioavailability of greater than 90%. One resource indicates that Cmax after a single oral dose of 500mg metronidazole ranges from 8 to 13 mg/L, with a Tmax of 25 minutes to 4 hours. The AUC following a single 500mg oral dose of metronidazole was 122 ± 10.3 mg/L • h. A note on the absorption of topical preparations Insignificant percutaneous absorption of metronidazole occurs after the application of 1% metronidazole cream topically. Healthy volunteers applied one 100 mg dose of 14C-labelled metronidazole 2% cream to unbroken skin. After 12 hours, metronidazole was not detected in the plasma. Approximately 0.1% to 1% of the administered metronidazole was measured in the urine and feces. •Volume of distribution (Drug A): No volume of distribution available •Volume of distribution (Drug B): Metronidazole is widely distributed throughout the body and various body fluids. They include the bile, saliva, breastmilk, cerebrospinal fluid, and the placenta. Steady-state volume distribution of metronidazole in adults ranges from 0.51 to 1.1 L/kg. It attains 60 to 100% of plasma concentrations in various tissues, such as the central nervous system, however, is not measured in high concentrations in the placental tissue. •Protein binding (Drug A): In vitro tests show that bupropion is 84% bound to human plasma proteins at concentrations up to 200 mcg per mL. The extent of protein binding of the hydroxybupropion metabolite is similar to that for bupropion, whereas the extent of protein binding of the threohydrobupropion metabolite is about half that seen with bupropion. •Protein binding (Drug B): Metronidazole is less than 20% bound to plasma proteins. •Metabolism (Drug A): Bupropion is extensively metabolized in humans. Three metabolites are active: hydroxybupropion, which is formed via hydroxylation of the tert-butyl group of bupropion, and the amino-alcohol isomers, threohydrobupropion and erythrohydrobupropion, which are formed via reduction of the carbonyl group. In vitro findings suggest that CYP2B6 is the principal isoenzyme involved in the formation of hydroxybupropion, while cytochrome P450 enzymes are not involved in the formation of threohydrobupropion. Hydroxybupropion has been shown to have the same affinity as bupropion for the norepinephrine transporter (NET) but approximately 50% of its antidepressant activity despite reaching concentrations of ~10-fold higher than that of the parent drug. Oxidation of the bupropion side chain results in the formation of a glycine conjugate of meta-chlorobenzoic acid, which is then excreted as the major urinary metabolite. The potency and toxicity of the metabolites relative to bupropion have not been fully characterized. However, it has been demonstrated in an antidepressant screening test in mice that hydroxybupropion is one-half as potent as bupropion, while threohydrobupropion and erythrohydrobupropion are 5-fold less potent than bupropion. This may be of clinical importance because the plasma concentrations of the metabolites are as high as or higher than those of bupropion. Bupropion and its metabolites exhibit linear kinetics following chronic administration of 300 to 450 mg per day. •Metabolism (Drug B): Metronidazole undergoes hepatic metabolism via hydroxylation, oxidation, and glucuronidation. The metabolism of metronidazole yields 5 metabolites. The hydroxy metabolite, 1-(2-hydroxy-ethyl)-2-hydroxy methyl-5-nitroimidazole, is considered the major active metabolite. Unchanged metronidazole is found in the plasma along with small amounts of its 2- hydroxymethyl metabolite. Several metabolites of metronidazole are found in the urine. They are primarily a product of side-chain oxidation in addition to glucuronide conjugation. Only 20% of the dose found in the urine is accounted for by unchanged metronidazole. The two main oxidative metabolites of metronidazole are hydroxy and acetic acid metabolites. •Route of elimination (Drug A): Bupropion is extensively metabolized in humans. Oxidation of the bupropion side chain results in the formation of a glycine conjugate of metachlorobenzoic acid, which is then excreted as the major urinary metabolite. Following oral administration of 200 mg of 14C-bupropion in humans, 87% and 10% of the radioactive dose were recovered in the urine and feces, respectively. However, the fraction of the oral dose of bupropion excreted unchanged was only 0.5%, a finding consistent with the extensive metabolism of bupropion. •Route of elimination (Drug B): Metronidazole and metabolites are 60 to 80% eliminated in the urine, and 6-15% excreted in the feces. •Half-life (Drug A): 24 hours •Half-life (Drug B): The elimination half-life of metronidazole is 7.3 ± 1.0 after a single 500mg IV dose in healthy subjects. Another resource indicates that the elimination half-life for metronidazole ranges from 6 to 10 hours. •Clearance (Drug A): No clearance available •Clearance (Drug B): Dose adjustments may be required in patients with hepatic impairment, as clearance is impaired in these patients. The clearance of metronidazole in the kidneys is estimated at 10 mL/min/1.73 m2. The total clearance from serum is about 2.1 to 6.4 L/h/kg. •Toxicity (Drug A): Symptoms of overdose include seizures, hallucinations, loss of consciousness, tachycardia, and cardiac arrest. •Toxicity (Drug B): LD50 information The oral LD50 of metronidazole in rats is 5000 mg/kg Overdose information Adverse effects that may be exaggerated with an overdose include peripheral neuropathy, central nervous system toxicity, seizures, disulfiram-like effect (if combined with alcohol) dark urine, a metallic taste in the mouth, nausea, epigastric discomfort, and vertigo, in addition to neutropenia. There is no specific antidote for metronidazole overdose. Symptomatic and supportive treatment should be employed in addition to the administration of activated charcoal to remove the unabsorbed drug from the gastrointestinal tract. In addition to the above measures, contact the local poison control center for updated information on the management of a metronidazole overdose. •Brand Names (Drug A): Aplenzin, Auvelity, Budeprion, Contrave, Forfivo, Wellbutrin, Zyban •Brand Names (Drug B): Flagyl, Flagystatin, Likmez, Metrocream, Metrogel, Metrolotion, Nidagel, Noritate, Nuvessa, Pylera, Rosadan, Vandazole •Synonyms (Drug A): No synonyms listed •Synonyms (Drug B): Metronidazol Métronidazole Metronidazole Metronidazolum •Summary (Drug A): Bupropion is a norepinephrine and dopamine reuptake inhibitor used in the treatment of major depressive disorder (MDD), seasonal affective disorder (SAD), and as an aid to smoking cessation. •Summary (Drug B): Metronidazole is a nitroimidazole used to treat trichomoniasis, amebiasis, inflammatory lesions of rosacea, and bacterial infections, as well as prevent postoperative infections. Output: Bupropion carries a dose-dependent risk of seizure1 that may be further exacerbated when combined with other medications that can reduce the seizure threshold (i.e. increase the risk of seizure), such as the affected drug. This risk may be also compounded by patient-specific factors that may increase the risk of seizure such as metabolic disorders and illicit drug use. The severity of the interaction is moderate.

Does Bupropion and Metyrapone interact?

•Drug A: Bupropion •Drug B: Metyrapone •Severity: MINOR •Description: Metyrapone may decrease the excretion rate of Bupropion which could result in a higher serum level. •Extended Description: The renal excretion of drugs is the overall result of a combination of kidney processes that include glomerular filtration, passive diffusion, tubular secretion, and tubular reabsorption. Since two of these mechanisms - tubular secretion and reabsorption - are saturable processes , they are consequently susceptible to competition between multiple substrates excreted by the kidneys. If two or more medications that are mainly renally excreted are co-administered, they may compete for renal elimination; there is a large likelihood that one agent may "out-compete" or saturate the renal excretion mechanisms before the other concomitantly administered agent(s) are excreted. As a result, the elimination of these other concurrently administered agents may be inhibited or otherwise delayed, which could lead to increases in their serum concentrations and the risk, incidence, and/or severity of adverse effects associated with the exposure to such drugs. •Indication (Drug A): Bupropion is indicated for the treatment of major depressive disorder (MDD), seasonal affective disorder (SAD), and as an aid to smoking cessation. When used in combination with naltrexone as the marketed product ContraveⓇ, bupropion is indicated as an adjunct to a reduced-calorie diet and increased physical activity for chronic weight management in adults with an initial body mass index (BMI) of: 30 kg/m^2 or greater (obese) or 27 kg/m^2 or greater (overweight) in the presence of at least one weight-related comorbid condition (e.g., hypertension, type 2 diabetes mellitus, or dyslipidemia). Bupropion is also used off-label as a first-line treatment in patients with ADHD and comorbid bipolar disorder when used as an adjunct to mood stabilizers. •Indication (Drug B): Used as a diagnostic drug for testing hypothalamic-pituitary ACTH function. Occasionally used in Cushing's syndrome. •Pharmacodynamics (Drug A): Bupropion is chemically unrelated to tricyclic, tetracyclic, selective serotonin re-uptake inhibitors, or other known antidepressant agents. Compared to classical tricyclic antidepressants, Bupropion is a relatively weak inhibitor of the neuronal uptake of norepinephrine and dopamine. In addition, Bupropion does not inhibit monoamine oxidase. Bupropion has been found to be essentially inactive at the serotonin transporter (SERT)(IC50 >10 000 nM), however both bupropion and its primary metabolite hydroxybupropion have been found to block the function of cation-selective serotonin type 3A receptors (5-HT3ARs). Bupropion produces dose-related central nervous system (CNS) stimulant effects in animals, as evidenced by increased locomotor activity, increased rates of responding in various schedule-controlled operant behaviour tasks, and, at high doses, induction of mild stereotyped behaviour. Due to these stimulant effects and selective activity at dopamine and norepinephrine receptors, bupropion has been identified as having an abuse potential. Bupropion has a similar structure to the controlled substance Cathinone, and has been identified as having mild amphetamine-like activity, particularly when inhaled or injected. Bupropion is also known to lower the seizure threshold, making any pre-existing seizure conditions a contraindication to its use. This risk is exacerbated when bupropion is combined with other drugs or substances that lower the seizure threshold, such as cocaine, or in clinical situations that would increase the risk of a seizure such as abrupt alcohol or benzodiazepine withdrawal. As norepinephrine has been shown to have anticonvulsant properties, bupropion's inhibitory effects on NET are thought to contribute to its pro-convulsant activity. Bupropion has been shown to increase blood pressure and pose a risk for exacerbation of unmanaged or pre-existing hypertension, however, clinical trials of bupropion in smokers with CVD have not identified an increased incidence of CV events including stroke or heart attack. In clinical trials, the mean increase in systolic blood pressure associated with the use of bupropion was found to be 1.3 mmHg. •Pharmacodynamics (Drug B): Metopirone is an inhibitor of endogenous adrenal corticosteroid synthesis. •Mechanism of action (Drug A): Bupropion is a norepinephrine/dopamine-reuptake inhibitor (NDRI) that exerts its pharmacological effects by weakly inhibiting the enzymes involved in the uptake of the neurotransmitters norepinephrine and dopamine from the synaptic cleft, therefore prolonging their duration of action within the neuronal synapse and the downstream effects of these neurotransmitters. More specifically, bupropion binds to the norepinephrine transporter (NET) and the dopamine transporter (DAT). Bupropion was originally classified as an "atypical" antidepressant because it does not exert the same effects as the classical antidepressants such as Monoamine Oxidase Inhibitors (MAOIs), Tricyclic Antidepressants (TCAs), or Selective Serotonin Reuptake Inhibitors (SSRIs). While it has comparable effectiveness to typical first-line options for the treatment of depression such as SSRIs, bupropion is a unique option for the treatment of MDD as it lacks any clinically relevant serotonergic effects, typical of other mood medications, or any effects on histamine or adrenaline receptors. Lack of activity at these receptors results in a more tolerable side effect profile; bupropion is less likely to cause sexual side effects, sedation, or weight gain as compared to SSRIs or TCAs, for example. When used as an aid to smoking cessation, bupropion is thought to confer its anti-craving and anti-withdrawal effects by inhibiting dopamine reuptake, which is thought to be involved in the reward pathways associated with nicotine, and through the antagonism of the nicotinic acetylcholinergic receptor (AChR), thereby blunting the effects of nicotine. Furthermore, the stimulatory effects produced by bupropion in the central nervous system are similar to nicotine's effects, making low doses of bupropion a suitable option as a nicotine substitute. When used in combination with naltrexone in the marketed product ContraveⓇ for chronic weight management, the two components are thought to have effects on areas of the brain involved in the regulation of food intake. This includes the hypothalamus, which is involved in appetite regulation, and the mesolimbic dopamine circuit, which is involved in reward pathways. Studies have shown that the combined activity of bupropion and naltrexone increase the firing rate of hypothalamic pro-opiomelanocortin (POMC) neurons and blockade of opioid receptor-mediated POMC auto-inhibition, which are associated with a reduction in food intake and increased energy expenditure. This combination was also found to reduce food intake when injected directly into the ventral tegmental area of the mesolimbic circuit in mice, which is an area associated with the regulation of reward pathways. •Mechanism of action (Drug B): The pharmacological effect of Metopirone is to reduce cortisol and corticosterone production by inhibiting the 11-ß-hydroxylation reaction in the adrenal cortex. Removal of the strong inhibitory feedback mechanism exerted by cortisol results in an increase in adrenocorticotropic hormone (ACTH) production by the pituitary. With continued blockade of the enzymatic steps leading to production of cortisol and corticosterone, there is a marked increase in adrenocortical secretion of their immediate precursors, 11-desoxycortisol and desoxycorticosterone, which are weak suppressors of ACTH release, and a corresponding elevation of these steroids in the plasma and of their metabolites in the urine. These metabolites are readily determined by measuring urinary 17-hydroxycorticosteroids (17-OHCS) or 17-ketogenic steroids (17-KGS). Because of these actions, metopirone is used as a diagnostic test, with urinary 17-OHCS measured as an index of pituitary ACTH responsiveness. Metopirone may also suppress biosynthesis of aldosterone, resulting in a mild natriuresis. •Absorption (Drug A): Bupropion is currently available in 3 distinct, but bioequivalent formulations: immediate release (IR), sustained-release (SR), and extended-release (XL). Immediate Release Formulation In humans, following oral administration of bupropion hydrochloride tablets, peak plasma bupropion concentrations are usually achieved within 2 hours. IR formulations provide a short duration of action and are therefore generally dosed three times per day. Sustained Release Formulation In humans, following oral administration of bupropion hydrochloride sustained-release tablets (SR), peak plasma concentration (Cmax) of bupropion is usually achieved within 3 hours. SR formulations provide a 12-hour extended release of medication and are therefore generally dosed twice per day. Extended Release Formulation Following single oral administration of bupropion hydrochloride extended-release tablets (XL) to healthy volunteers, the median time to peak plasma concentrations for bupropion was approximately 5 hours. The presence of food did not affect the peak concentration or area under the curve of bupropion. XL formulations provide a 24-hour extended release of medication and are therefore generally dosed once per day/ In a trial comparing chronic dosing with bupropion hydrochloride extended-release tablets (SR) 150 mg twice daily to bupropion immediate-release formulation 100 mg 3 times daily, the steady state Cmax for bupropion after bupropion hydrochloride sustained-release tablets (SR) administration was approximately 85% of those achieved after bupropion immediate-release formulation administration. Exposure (AUC) to bupropion was equivalent for both formulations. Bioequivalence was also demonstrated for all three major active metabolites (i.e., hydroxybupropion, threohydrobupropion and erythrohydrobupropion) for both Cmax and AUC. Thus, at steady state, bupropion hydrochloride sustained-release tablets (SR) given twice daily, and the immediate-release formulation of bupropion given 3 times daily, are essentially bioequivalent for both bupropion and the 3 quantitatively important metabolites. Furthermore, in a study comparing 14-day dosing with bupropion hydrochloride extended-release tablets (XL), 300 mg once-daily to the immediate-release formulation of bupropion at 100 mg 3 times daily, equivalence was demonstrated for peak plasma concentration and area under the curve for bupropion and the three metabolites (hydroxybupropion, threohydrobupropion, and erythrohydrobupropion). Additionally, in a study comparing 14-day dosing with bupropion hydrochloride extended-release tablets (XL) 300 mg once daily to the sustained-release formulation of bupropion at 150 mg 2 times daily, equivalence was demonstrated for peak plasma concentration and area under the curve for bupropion and the three metabolites. Bupropion hydrochloride extended-release tablets (SR) can be taken with or without food. Bupropion Cmax and AUC were increased by 11% to 35% and 16% to 19%, respectively, when bupropion hydrochloride extended-release tablets (SR) was administered with food to healthy volunteers in three trials. The food effect is not considered clinically significant. Following a single-dose administration of bupropion hydrochloride extended-release tablets (SR) in humans, Cmax of bupropion's metabolite hydroxybupropion occurs approximately 6 hours post-dose and is approximately 10 times the peak level of the parent drug at steady state. The elimination half-life of hydroxybupropion is approximately 20 (±5) hours and its AUC at steady state is about 17 times that of bupropion. The times to peak concentrations for the erythrohydrobupropion and threohydrobupropion metabolites are similar to that of the hydroxybupropion metabolite. However, their elimination half-lives are longer, 33(±10) and 37 (±13) hours, respectively, and steady-state AUCs are 1.5 and 7 times that of bupropion, respectively. •Absorption (Drug B): Absorbed rapidly and well when administered orally. Peak plasma concentrations are usually reached 1 hour after administration. •Volume of distribution (Drug A): No volume of distribution available •Volume of distribution (Drug B): No volume of distribution available •Protein binding (Drug A): In vitro tests show that bupropion is 84% bound to human plasma proteins at concentrations up to 200 mcg per mL. The extent of protein binding of the hydroxybupropion metabolite is similar to that for bupropion, whereas the extent of protein binding of the threohydrobupropion metabolite is about half that seen with bupropion. •Protein binding (Drug B): No protein binding available •Metabolism (Drug A): Bupropion is extensively metabolized in humans. Three metabolites are active: hydroxybupropion, which is formed via hydroxylation of the tert-butyl group of bupropion, and the amino-alcohol isomers, threohydrobupropion and erythrohydrobupropion, which are formed via reduction of the carbonyl group. In vitro findings suggest that CYP2B6 is the principal isoenzyme involved in the formation of hydroxybupropion, while cytochrome P450 enzymes are not involved in the formation of threohydrobupropion. Hydroxybupropion has been shown to have the same affinity as bupropion for the norepinephrine transporter (NET) but approximately 50% of its antidepressant activity despite reaching concentrations of ~10-fold higher than that of the parent drug. Oxidation of the bupropion side chain results in the formation of a glycine conjugate of meta-chlorobenzoic acid, which is then excreted as the major urinary metabolite. The potency and toxicity of the metabolites relative to bupropion have not been fully characterized. However, it has been demonstrated in an antidepressant screening test in mice that hydroxybupropion is one-half as potent as bupropion, while threohydrobupropion and erythrohydrobupropion are 5-fold less potent than bupropion. This may be of clinical importance because the plasma concentrations of the metabolites are as high as or higher than those of bupropion. Bupropion and its metabolites exhibit linear kinetics following chronic administration of 300 to 450 mg per day. •Metabolism (Drug B): Hepatic. The major biotransformation is reduction of the ketone to metyrapol, an active alcohol metabolite. Metyrapone and metyrapol are both conjugated with glucuronide. •Route of elimination (Drug A): Bupropion is extensively metabolized in humans. Oxidation of the bupropion side chain results in the formation of a glycine conjugate of metachlorobenzoic acid, which is then excreted as the major urinary metabolite. Following oral administration of 200 mg of 14C-bupropion in humans, 87% and 10% of the radioactive dose were recovered in the urine and feces, respectively. However, the fraction of the oral dose of bupropion excreted unchanged was only 0.5%, a finding consistent with the extensive metabolism of bupropion. •Route of elimination (Drug B): After administration of 4.5 g metyrapone (750 mg every 4 hours), an average of 5.3% of the dose was excreted in the urine in the form of metyrapone (9.2% free and 90.8% as glucuronide) and 38.5% in the form of metyrapol (8.1% free and 91.9% as glucuronide) within 72 hours after the first dose was given. •Half-life (Drug A): 24 hours •Half-life (Drug B): 1.9 ±0.7 hours. •Clearance (Drug A): No clearance available •Clearance (Drug B): No clearance available •Toxicity (Drug A): Symptoms of overdose include seizures, hallucinations, loss of consciousness, tachycardia, and cardiac arrest. •Toxicity (Drug B): Oral LD 50 in rats is 521 mg/kg. One case has been recorded in which a 6-year-old girl died after two doses of Metopirone, 2 g. Symptoms of overdose include cardiac arrhythmias, hypotension, dehydration, anxiety, confusion, weakness, impairment of consciousness, nausea, vomiting, epigastric pain, and diarrhea. •Brand Names (Drug A): Aplenzin, Auvelity, Budeprion, Contrave, Forfivo, Wellbutrin, Zyban •Brand Names (Drug B): Metopirone •Synonyms (Drug A): No synonyms listed •Synonyms (Drug B): No synonyms listed •Summary (Drug A): Bupropion is a norepinephrine and dopamine reuptake inhibitor used in the treatment of major depressive disorder (MDD), seasonal affective disorder (SAD), and as an aid to smoking cessation. •Summary (Drug B): Metyrapone is a steroid 11-beta-monooxygenase inhibitor used to test hypothalamic-pituitary ACTH function.

The renal excretion of drugs is the overall result of a combination of kidney processes that include glomerular filtration, passive diffusion, tubular secretion, and tubular reabsorption. Since two of these mechanisms - tubular secretion and reabsorption - are saturable processes , they are consequently susceptible to competition between multiple substrates excreted by the kidneys. If two or more medications that are mainly renally excreted are co-administered, they may compete for renal elimination; there is a large likelihood that one agent may "out-compete" or saturate the renal excretion mechanisms before the other concomitantly administered agent(s) are excreted. As a result, the elimination of these other concurrently administered agents may be inhibited or otherwise delayed, which could lead to increases in their serum concentrations and the risk, incidence, and/or severity of adverse effects associated with the exposure to such drugs. The severity of the interaction is minor.

Question: Does Bupropion and Metyrapone interact? Information: •Drug A: Bupropion •Drug B: Metyrapone •Severity: MINOR •Description: Metyrapone may decrease the excretion rate of Bupropion which could result in a higher serum level. •Extended Description: The renal excretion of drugs is the overall result of a combination of kidney processes that include glomerular filtration, passive diffusion, tubular secretion, and tubular reabsorption. Since two of these mechanisms - tubular secretion and reabsorption - are saturable processes , they are consequently susceptible to competition between multiple substrates excreted by the kidneys. If two or more medications that are mainly renally excreted are co-administered, they may compete for renal elimination; there is a large likelihood that one agent may "out-compete" or saturate the renal excretion mechanisms before the other concomitantly administered agent(s) are excreted. As a result, the elimination of these other concurrently administered agents may be inhibited or otherwise delayed, which could lead to increases in their serum concentrations and the risk, incidence, and/or severity of adverse effects associated with the exposure to such drugs. •Indication (Drug A): Bupropion is indicated for the treatment of major depressive disorder (MDD), seasonal affective disorder (SAD), and as an aid to smoking cessation. When used in combination with naltrexone as the marketed product ContraveⓇ, bupropion is indicated as an adjunct to a reduced-calorie diet and increased physical activity for chronic weight management in adults with an initial body mass index (BMI) of: 30 kg/m^2 or greater (obese) or 27 kg/m^2 or greater (overweight) in the presence of at least one weight-related comorbid condition (e.g., hypertension, type 2 diabetes mellitus, or dyslipidemia). Bupropion is also used off-label as a first-line treatment in patients with ADHD and comorbid bipolar disorder when used as an adjunct to mood stabilizers. •Indication (Drug B): Used as a diagnostic drug for testing hypothalamic-pituitary ACTH function. Occasionally used in Cushing's syndrome. •Pharmacodynamics (Drug A): Bupropion is chemically unrelated to tricyclic, tetracyclic, selective serotonin re-uptake inhibitors, or other known antidepressant agents. Compared to classical tricyclic antidepressants, Bupropion is a relatively weak inhibitor of the neuronal uptake of norepinephrine and dopamine. In addition, Bupropion does not inhibit monoamine oxidase. Bupropion has been found to be essentially inactive at the serotonin transporter (SERT)(IC50 >10 000 nM), however both bupropion and its primary metabolite hydroxybupropion have been found to block the function of cation-selective serotonin type 3A receptors (5-HT3ARs). Bupropion produces dose-related central nervous system (CNS) stimulant effects in animals, as evidenced by increased locomotor activity, increased rates of responding in various schedule-controlled operant behaviour tasks, and, at high doses, induction of mild stereotyped behaviour. Due to these stimulant effects and selective activity at dopamine and norepinephrine receptors, bupropion has been identified as having an abuse potential. Bupropion has a similar structure to the controlled substance Cathinone, and has been identified as having mild amphetamine-like activity, particularly when inhaled or injected. Bupropion is also known to lower the seizure threshold, making any pre-existing seizure conditions a contraindication to its use. This risk is exacerbated when bupropion is combined with other drugs or substances that lower the seizure threshold, such as cocaine, or in clinical situations that would increase the risk of a seizure such as abrupt alcohol or benzodiazepine withdrawal. As norepinephrine has been shown to have anticonvulsant properties, bupropion's inhibitory effects on NET are thought to contribute to its pro-convulsant activity. Bupropion has been shown to increase blood pressure and pose a risk for exacerbation of unmanaged or pre-existing hypertension, however, clinical trials of bupropion in smokers with CVD have not identified an increased incidence of CV events including stroke or heart attack. In clinical trials, the mean increase in systolic blood pressure associated with the use of bupropion was found to be 1.3 mmHg. •Pharmacodynamics (Drug B): Metopirone is an inhibitor of endogenous adrenal corticosteroid synthesis. •Mechanism of action (Drug A): Bupropion is a norepinephrine/dopamine-reuptake inhibitor (NDRI) that exerts its pharmacological effects by weakly inhibiting the enzymes involved in the uptake of the neurotransmitters norepinephrine and dopamine from the synaptic cleft, therefore prolonging their duration of action within the neuronal synapse and the downstream effects of these neurotransmitters. More specifically, bupropion binds to the norepinephrine transporter (NET) and the dopamine transporter (DAT). Bupropion was originally classified as an "atypical" antidepressant because it does not exert the same effects as the classical antidepressants such as Monoamine Oxidase Inhibitors (MAOIs), Tricyclic Antidepressants (TCAs), or Selective Serotonin Reuptake Inhibitors (SSRIs). While it has comparable effectiveness to typical first-line options for the treatment of depression such as SSRIs, bupropion is a unique option for the treatment of MDD as it lacks any clinically relevant serotonergic effects, typical of other mood medications, or any effects on histamine or adrenaline receptors. Lack of activity at these receptors results in a more tolerable side effect profile; bupropion is less likely to cause sexual side effects, sedation, or weight gain as compared to SSRIs or TCAs, for example. When used as an aid to smoking cessation, bupropion is thought to confer its anti-craving and anti-withdrawal effects by inhibiting dopamine reuptake, which is thought to be involved in the reward pathways associated with nicotine, and through the antagonism of the nicotinic acetylcholinergic receptor (AChR), thereby blunting the effects of nicotine. Furthermore, the stimulatory effects produced by bupropion in the central nervous system are similar to nicotine's effects, making low doses of bupropion a suitable option as a nicotine substitute. When used in combination with naltrexone in the marketed product ContraveⓇ for chronic weight management, the two components are thought to have effects on areas of the brain involved in the regulation of food intake. This includes the hypothalamus, which is involved in appetite regulation, and the mesolimbic dopamine circuit, which is involved in reward pathways. Studies have shown that the combined activity of bupropion and naltrexone increase the firing rate of hypothalamic pro-opiomelanocortin (POMC) neurons and blockade of opioid receptor-mediated POMC auto-inhibition, which are associated with a reduction in food intake and increased energy expenditure. This combination was also found to reduce food intake when injected directly into the ventral tegmental area of the mesolimbic circuit in mice, which is an area associated with the regulation of reward pathways. •Mechanism of action (Drug B): The pharmacological effect of Metopirone is to reduce cortisol and corticosterone production by inhibiting the 11-ß-hydroxylation reaction in the adrenal cortex. Removal of the strong inhibitory feedback mechanism exerted by cortisol results in an increase in adrenocorticotropic hormone (ACTH) production by the pituitary. With continued blockade of the enzymatic steps leading to production of cortisol and corticosterone, there is a marked increase in adrenocortical secretion of their immediate precursors, 11-desoxycortisol and desoxycorticosterone, which are weak suppressors of ACTH release, and a corresponding elevation of these steroids in the plasma and of their metabolites in the urine. These metabolites are readily determined by measuring urinary 17-hydroxycorticosteroids (17-OHCS) or 17-ketogenic steroids (17-KGS). Because of these actions, metopirone is used as a diagnostic test, with urinary 17-OHCS measured as an index of pituitary ACTH responsiveness. Metopirone may also suppress biosynthesis of aldosterone, resulting in a mild natriuresis. •Absorption (Drug A): Bupropion is currently available in 3 distinct, but bioequivalent formulations: immediate release (IR), sustained-release (SR), and extended-release (XL). Immediate Release Formulation In humans, following oral administration of bupropion hydrochloride tablets, peak plasma bupropion concentrations are usually achieved within 2 hours. IR formulations provide a short duration of action and are therefore generally dosed three times per day. Sustained Release Formulation In humans, following oral administration of bupropion hydrochloride sustained-release tablets (SR), peak plasma concentration (Cmax) of bupropion is usually achieved within 3 hours. SR formulations provide a 12-hour extended release of medication and are therefore generally dosed twice per day. Extended Release Formulation Following single oral administration of bupropion hydrochloride extended-release tablets (XL) to healthy volunteers, the median time to peak plasma concentrations for bupropion was approximately 5 hours. The presence of food did not affect the peak concentration or area under the curve of bupropion. XL formulations provide a 24-hour extended release of medication and are therefore generally dosed once per day/ In a trial comparing chronic dosing with bupropion hydrochloride extended-release tablets (SR) 150 mg twice daily to bupropion immediate-release formulation 100 mg 3 times daily, the steady state Cmax for bupropion after bupropion hydrochloride sustained-release tablets (SR) administration was approximately 85% of those achieved after bupropion immediate-release formulation administration. Exposure (AUC) to bupropion was equivalent for both formulations. Bioequivalence was also demonstrated for all three major active metabolites (i.e., hydroxybupropion, threohydrobupropion and erythrohydrobupropion) for both Cmax and AUC. Thus, at steady state, bupropion hydrochloride sustained-release tablets (SR) given twice daily, and the immediate-release formulation of bupropion given 3 times daily, are essentially bioequivalent for both bupropion and the 3 quantitatively important metabolites. Furthermore, in a study comparing 14-day dosing with bupropion hydrochloride extended-release tablets (XL), 300 mg once-daily to the immediate-release formulation of bupropion at 100 mg 3 times daily, equivalence was demonstrated for peak plasma concentration and area under the curve for bupropion and the three metabolites (hydroxybupropion, threohydrobupropion, and erythrohydrobupropion). Additionally, in a study comparing 14-day dosing with bupropion hydrochloride extended-release tablets (XL) 300 mg once daily to the sustained-release formulation of bupropion at 150 mg 2 times daily, equivalence was demonstrated for peak plasma concentration and area under the curve for bupropion and the three metabolites. Bupropion hydrochloride extended-release tablets (SR) can be taken with or without food. Bupropion Cmax and AUC were increased by 11% to 35% and 16% to 19%, respectively, when bupropion hydrochloride extended-release tablets (SR) was administered with food to healthy volunteers in three trials. The food effect is not considered clinically significant. Following a single-dose administration of bupropion hydrochloride extended-release tablets (SR) in humans, Cmax of bupropion's metabolite hydroxybupropion occurs approximately 6 hours post-dose and is approximately 10 times the peak level of the parent drug at steady state. The elimination half-life of hydroxybupropion is approximately 20 (±5) hours and its AUC at steady state is about 17 times that of bupropion. The times to peak concentrations for the erythrohydrobupropion and threohydrobupropion metabolites are similar to that of the hydroxybupropion metabolite. However, their elimination half-lives are longer, 33(±10) and 37 (±13) hours, respectively, and steady-state AUCs are 1.5 and 7 times that of bupropion, respectively. •Absorption (Drug B): Absorbed rapidly and well when administered orally. Peak plasma concentrations are usually reached 1 hour after administration. •Volume of distribution (Drug A): No volume of distribution available •Volume of distribution (Drug B): No volume of distribution available •Protein binding (Drug A): In vitro tests show that bupropion is 84% bound to human plasma proteins at concentrations up to 200 mcg per mL. The extent of protein binding of the hydroxybupropion metabolite is similar to that for bupropion, whereas the extent of protein binding of the threohydrobupropion metabolite is about half that seen with bupropion. •Protein binding (Drug B): No protein binding available •Metabolism (Drug A): Bupropion is extensively metabolized in humans. Three metabolites are active: hydroxybupropion, which is formed via hydroxylation of the tert-butyl group of bupropion, and the amino-alcohol isomers, threohydrobupropion and erythrohydrobupropion, which are formed via reduction of the carbonyl group. In vitro findings suggest that CYP2B6 is the principal isoenzyme involved in the formation of hydroxybupropion, while cytochrome P450 enzymes are not involved in the formation of threohydrobupropion. Hydroxybupropion has been shown to have the same affinity as bupropion for the norepinephrine transporter (NET) but approximately 50% of its antidepressant activity despite reaching concentrations of ~10-fold higher than that of the parent drug. Oxidation of the bupropion side chain results in the formation of a glycine conjugate of meta-chlorobenzoic acid, which is then excreted as the major urinary metabolite. The potency and toxicity of the metabolites relative to bupropion have not been fully characterized. However, it has been demonstrated in an antidepressant screening test in mice that hydroxybupropion is one-half as potent as bupropion, while threohydrobupropion and erythrohydrobupropion are 5-fold less potent than bupropion. This may be of clinical importance because the plasma concentrations of the metabolites are as high as or higher than those of bupropion. Bupropion and its metabolites exhibit linear kinetics following chronic administration of 300 to 450 mg per day. •Metabolism (Drug B): Hepatic. The major biotransformation is reduction of the ketone to metyrapol, an active alcohol metabolite. Metyrapone and metyrapol are both conjugated with glucuronide. •Route of elimination (Drug A): Bupropion is extensively metabolized in humans. Oxidation of the bupropion side chain results in the formation of a glycine conjugate of metachlorobenzoic acid, which is then excreted as the major urinary metabolite. Following oral administration of 200 mg of 14C-bupropion in humans, 87% and 10% of the radioactive dose were recovered in the urine and feces, respectively. However, the fraction of the oral dose of bupropion excreted unchanged was only 0.5%, a finding consistent with the extensive metabolism of bupropion. •Route of elimination (Drug B): After administration of 4.5 g metyrapone (750 mg every 4 hours), an average of 5.3% of the dose was excreted in the urine in the form of metyrapone (9.2% free and 90.8% as glucuronide) and 38.5% in the form of metyrapol (8.1% free and 91.9% as glucuronide) within 72 hours after the first dose was given. •Half-life (Drug A): 24 hours •Half-life (Drug B): 1.9 ±0.7 hours. •Clearance (Drug A): No clearance available •Clearance (Drug B): No clearance available •Toxicity (Drug A): Symptoms of overdose include seizures, hallucinations, loss of consciousness, tachycardia, and cardiac arrest. •Toxicity (Drug B): Oral LD 50 in rats is 521 mg/kg. One case has been recorded in which a 6-year-old girl died after two doses of Metopirone, 2 g. Symptoms of overdose include cardiac arrhythmias, hypotension, dehydration, anxiety, confusion, weakness, impairment of consciousness, nausea, vomiting, epigastric pain, and diarrhea. •Brand Names (Drug A): Aplenzin, Auvelity, Budeprion, Contrave, Forfivo, Wellbutrin, Zyban •Brand Names (Drug B): Metopirone •Synonyms (Drug A): No synonyms listed •Synonyms (Drug B): No synonyms listed •Summary (Drug A): Bupropion is a norepinephrine and dopamine reuptake inhibitor used in the treatment of major depressive disorder (MDD), seasonal affective disorder (SAD), and as an aid to smoking cessation. •Summary (Drug B): Metyrapone is a steroid 11-beta-monooxygenase inhibitor used to test hypothalamic-pituitary ACTH function. Output: The renal excretion of drugs is the overall result of a combination of kidney processes that include glomerular filtration, passive diffusion, tubular secretion, and tubular reabsorption. Since two of these mechanisms - tubular secretion and reabsorption - are saturable processes , they are consequently susceptible to competition between multiple substrates excreted by the kidneys. If two or more medications that are mainly renally excreted are co-administered, they may compete for renal elimination; there is a large likelihood that one agent may "out-compete" or saturate the renal excretion mechanisms before the other concomitantly administered agent(s) are excreted. As a result, the elimination of these other concurrently administered agents may be inhibited or otherwise delayed, which could lead to increases in their serum concentrations and the risk, incidence, and/or severity of adverse effects associated with the exposure to such drugs. The severity of the interaction is minor.

Does Bupropion and Metyrosine interact?

•Drug A: Bupropion •Drug B: Metyrosine •Severity: MODERATE •Description: Bupropion may increase the sedative activities of Metyrosine. •Extended Description: Central nervous system depressants may potentiate the sedative effects of metyrosine, due to additive pharmacological effects. •Indication (Drug A): Bupropion is indicated for the treatment of major depressive disorder (MDD), seasonal affective disorder (SAD), and as an aid to smoking cessation. When used in combination with naltrexone as the marketed product ContraveⓇ, bupropion is indicated as an adjunct to a reduced-calorie diet and increased physical activity for chronic weight management in adults with an initial body mass index (BMI) of: 30 kg/m^2 or greater (obese) or 27 kg/m^2 or greater (overweight) in the presence of at least one weight-related comorbid condition (e.g., hypertension, type 2 diabetes mellitus, or dyslipidemia). Bupropion is also used off-label as a first-line treatment in patients with ADHD and comorbid bipolar disorder when used as an adjunct to mood stabilizers. •Indication (Drug B): For use in the treatment of patients with pheochromocytoma, for preoperative preparation of patients for surgery, management of patients when surgery is contraindicated, and chronic treatment of patients with malignant pheochromocytoma. •Pharmacodynamics (Drug A): Bupropion is chemically unrelated to tricyclic, tetracyclic, selective serotonin re-uptake inhibitors, or other known antidepressant agents. Compared to classical tricyclic antidepressants, Bupropion is a relatively weak inhibitor of the neuronal uptake of norepinephrine and dopamine. In addition, Bupropion does not inhibit monoamine oxidase. Bupropion has been found to be essentially inactive at the serotonin transporter (SERT)(IC50 >10 000 nM), however both bupropion and its primary metabolite hydroxybupropion have been found to block the function of cation-selective serotonin type 3A receptors (5-HT3ARs). Bupropion produces dose-related central nervous system (CNS) stimulant effects in animals, as evidenced by increased locomotor activity, increased rates of responding in various schedule-controlled operant behaviour tasks, and, at high doses, induction of mild stereotyped behaviour. Due to these stimulant effects and selective activity at dopamine and norepinephrine receptors, bupropion has been identified as having an abuse potential. Bupropion has a similar structure to the controlled substance Cathinone, and has been identified as having mild amphetamine-like activity, particularly when inhaled or injected. Bupropion is also known to lower the seizure threshold, making any pre-existing seizure conditions a contraindication to its use. This risk is exacerbated when bupropion is combined with other drugs or substances that lower the seizure threshold, such as cocaine, or in clinical situations that would increase the risk of a seizure such as abrupt alcohol or benzodiazepine withdrawal. As norepinephrine has been shown to have anticonvulsant properties, bupropion's inhibitory effects on NET are thought to contribute to its pro-convulsant activity. Bupropion has been shown to increase blood pressure and pose a risk for exacerbation of unmanaged or pre-existing hypertension, however, clinical trials of bupropion in smokers with CVD have not identified an increased incidence of CV events including stroke or heart attack. In clinical trials, the mean increase in systolic blood pressure associated with the use of bupropion was found to be 1.3 mmHg. •Pharmacodynamics (Drug B): In patients with pheochromocytoma, who produce excessive amounts of norepinephrine and epinephrine, administration of one to four grams of metyrosine per day has reduced catecholamine biosynthesis from about 35 to 80 percent as measured by the total excretion of catecholamines and their metabolites (metanephrine and vanillylmandelic acid). The maximum biochemical effect usually occurs within two to three days, and the urinary concentration of catecholamines and their metabolites usually returns to pretreatment levels within three to four days after metyrosine is discontinued. Most patients with pheochromocytoma treated with metyrosine experience decreased frequency and severity of hypertensive attacks with their associated headache, nausea, sweating, and tachycardia. In patients who respond, blood pressure decreases progressively during the first two days of therapy with metyrosine; after withdrawal, blood pressure usually increases gradually to pretreatment values within two to three days. •Mechanism of action (Drug A): Bupropion is a norepinephrine/dopamine-reuptake inhibitor (NDRI) that exerts its pharmacological effects by weakly inhibiting the enzymes involved in the uptake of the neurotransmitters norepinephrine and dopamine from the synaptic cleft, therefore prolonging their duration of action within the neuronal synapse and the downstream effects of these neurotransmitters. More specifically, bupropion binds to the norepinephrine transporter (NET) and the dopamine transporter (DAT). Bupropion was originally classified as an "atypical" antidepressant because it does not exert the same effects as the classical antidepressants such as Monoamine Oxidase Inhibitors (MAOIs), Tricyclic Antidepressants (TCAs), or Selective Serotonin Reuptake Inhibitors (SSRIs). While it has comparable effectiveness to typical first-line options for the treatment of depression such as SSRIs, bupropion is a unique option for the treatment of MDD as it lacks any clinically relevant serotonergic effects, typical of other mood medications, or any effects on histamine or adrenaline receptors. Lack of activity at these receptors results in a more tolerable side effect profile; bupropion is less likely to cause sexual side effects, sedation, or weight gain as compared to SSRIs or TCAs, for example. When used as an aid to smoking cessation, bupropion is thought to confer its anti-craving and anti-withdrawal effects by inhibiting dopamine reuptake, which is thought to be involved in the reward pathways associated with nicotine, and through the antagonism of the nicotinic acetylcholinergic receptor (AChR), thereby blunting the effects of nicotine. Furthermore, the stimulatory effects produced by bupropion in the central nervous system are similar to nicotine's effects, making low doses of bupropion a suitable option as a nicotine substitute. When used in combination with naltrexone in the marketed product ContraveⓇ for chronic weight management, the two components are thought to have effects on areas of the brain involved in the regulation of food intake. This includes the hypothalamus, which is involved in appetite regulation, and the mesolimbic dopamine circuit, which is involved in reward pathways. Studies have shown that the combined activity of bupropion and naltrexone increase the firing rate of hypothalamic pro-opiomelanocortin (POMC) neurons and blockade of opioid receptor-mediated POMC auto-inhibition, which are associated with a reduction in food intake and increased energy expenditure. This combination was also found to reduce food intake when injected directly into the ventral tegmental area of the mesolimbic circuit in mice, which is an area associated with the regulation of reward pathways. •Mechanism of action (Drug B): Metyrosine inhibits tyrosine hydroxylase, which catalyzes the first transformation in catecholamine biosynthesis, i.e., the conversion of tyrosine to dihydroxyphenylalanine (DOPA). Because the first step is also the rate-limiting step, blockade of tyrosine hydroxylase activity results in decreased endogenous levels of catecholamines and their synthesis. This consequently, depletes the levels of the catecholamines dopamine, adrenaline and noradrenaline in the body,usually measured as decreased urinary excretion of catecholamines and their metabolites. One main end result of the catecholamine depletion is a decrease in blood presure. •Absorption (Drug A): Bupropion is currently available in 3 distinct, but bioequivalent formulations: immediate release (IR), sustained-release (SR), and extended-release (XL). Immediate Release Formulation In humans, following oral administration of bupropion hydrochloride tablets, peak plasma bupropion concentrations are usually achieved within 2 hours. IR formulations provide a short duration of action and are therefore generally dosed three times per day. Sustained Release Formulation In humans, following oral administration of bupropion hydrochloride sustained-release tablets (SR), peak plasma concentration (Cmax) of bupropion is usually achieved within 3 hours. SR formulations provide a 12-hour extended release of medication and are therefore generally dosed twice per day. Extended Release Formulation Following single oral administration of bupropion hydrochloride extended-release tablets (XL) to healthy volunteers, the median time to peak plasma concentrations for bupropion was approximately 5 hours. The presence of food did not affect the peak concentration or area under the curve of bupropion. XL formulations provide a 24-hour extended release of medication and are therefore generally dosed once per day/ In a trial comparing chronic dosing with bupropion hydrochloride extended-release tablets (SR) 150 mg twice daily to bupropion immediate-release formulation 100 mg 3 times daily, the steady state Cmax for bupropion after bupropion hydrochloride sustained-release tablets (SR) administration was approximately 85% of those achieved after bupropion immediate-release formulation administration. Exposure (AUC) to bupropion was equivalent for both formulations. Bioequivalence was also demonstrated for all three major active metabolites (i.e., hydroxybupropion, threohydrobupropion and erythrohydrobupropion) for both Cmax and AUC. Thus, at steady state, bupropion hydrochloride sustained-release tablets (SR) given twice daily, and the immediate-release formulation of bupropion given 3 times daily, are essentially bioequivalent for both bupropion and the 3 quantitatively important metabolites. Furthermore, in a study comparing 14-day dosing with bupropion hydrochloride extended-release tablets (XL), 300 mg once-daily to the immediate-release formulation of bupropion at 100 mg 3 times daily, equivalence was demonstrated for peak plasma concentration and area under the curve for bupropion and the three metabolites (hydroxybupropion, threohydrobupropion, and erythrohydrobupropion). Additionally, in a study comparing 14-day dosing with bupropion hydrochloride extended-release tablets (XL) 300 mg once daily to the sustained-release formulation of bupropion at 150 mg 2 times daily, equivalence was demonstrated for peak plasma concentration and area under the curve for bupropion and the three metabolites. Bupropion hydrochloride extended-release tablets (SR) can be taken with or without food. Bupropion Cmax and AUC were increased by 11% to 35% and 16% to 19%, respectively, when bupropion hydrochloride extended-release tablets (SR) was administered with food to healthy volunteers in three trials. The food effect is not considered clinically significant. Following a single-dose administration of bupropion hydrochloride extended-release tablets (SR) in humans, Cmax of bupropion's metabolite hydroxybupropion occurs approximately 6 hours post-dose and is approximately 10 times the peak level of the parent drug at steady state. The elimination half-life of hydroxybupropion is approximately 20 (±5) hours and its AUC at steady state is about 17 times that of bupropion. The times to peak concentrations for the erythrohydrobupropion and threohydrobupropion metabolites are similar to that of the hydroxybupropion metabolite. However, their elimination half-lives are longer, 33(±10) and 37 (±13) hours, respectively, and steady-state AUCs are 1.5 and 7 times that of bupropion, respectively. •Absorption (Drug B): Well absorbed from the gastrointestinal tract. •Volume of distribution (Drug A): No volume of distribution available •Volume of distribution (Drug B): No volume of distribution available •Protein binding (Drug A): In vitro tests show that bupropion is 84% bound to human plasma proteins at concentrations up to 200 mcg per mL. The extent of protein binding of the hydroxybupropion metabolite is similar to that for bupropion, whereas the extent of protein binding of the threohydrobupropion metabolite is about half that seen with bupropion. •Protein binding (Drug B): No protein binding available •Metabolism (Drug A): Bupropion is extensively metabolized in humans. Three metabolites are active: hydroxybupropion, which is formed via hydroxylation of the tert-butyl group of bupropion, and the amino-alcohol isomers, threohydrobupropion and erythrohydrobupropion, which are formed via reduction of the carbonyl group. In vitro findings suggest that CYP2B6 is the principal isoenzyme involved in the formation of hydroxybupropion, while cytochrome P450 enzymes are not involved in the formation of threohydrobupropion. Hydroxybupropion has been shown to have the same affinity as bupropion for the norepinephrine transporter (NET) but approximately 50% of its antidepressant activity despite reaching concentrations of ~10-fold higher than that of the parent drug. Oxidation of the bupropion side chain results in the formation of a glycine conjugate of meta-chlorobenzoic acid, which is then excreted as the major urinary metabolite. The potency and toxicity of the metabolites relative to bupropion have not been fully characterized. However, it has been demonstrated in an antidepressant screening test in mice that hydroxybupropion is one-half as potent as bupropion, while threohydrobupropion and erythrohydrobupropion are 5-fold less potent than bupropion. This may be of clinical importance because the plasma concentrations of the metabolites are as high as or higher than those of bupropion. Bupropion and its metabolites exhibit linear kinetics following chronic administration of 300 to 450 mg per day. •Metabolism (Drug B): Little biotransformation, with catechol metabolites accounting for less than 1% of the administered dose. •Route of elimination (Drug A): Bupropion is extensively metabolized in humans. Oxidation of the bupropion side chain results in the formation of a glycine conjugate of metachlorobenzoic acid, which is then excreted as the major urinary metabolite. Following oral administration of 200 mg of 14C-bupropion in humans, 87% and 10% of the radioactive dose were recovered in the urine and feces, respectively. However, the fraction of the oral dose of bupropion excreted unchanged was only 0.5%, a finding consistent with the extensive metabolism of bupropion. •Route of elimination (Drug B): Because the first step is also the rate-limiting step, blockade of tyrosine hydroxylase activity results in decreased endogenous levels of catecholamines, usually measured as decreased urinary excretion of catecholamines and their metabolites. •Half-life (Drug A): 24 hours •Half-life (Drug B): 3.4 to 3.7 hours •Clearance (Drug A): No clearance available •Clearance (Drug B): No clearance available •Toxicity (Drug A): Symptoms of overdose include seizures, hallucinations, loss of consciousness, tachycardia, and cardiac arrest. •Toxicity (Drug B): Signs of metyrosine overdosage include those central nervous system effects observed in some patients even at low dosages. At doses exceeding 2000 mg/day, some degree of sedation or feeling of fatigue may persist. Doses of 2000-4000 mg/day can result in anxiety or agitated depression, neuromuscular effects (including fine tremor of the hands, gross tremor of the trunk, tightening of the jaw with trismus), diarrhea, and decreased salivation with dry mouth. The acute toxicity of metyrosine was 442 mg/kg and 752 mg/kg in the female mouse and rat respectively. •Brand Names (Drug A): Aplenzin, Auvelity, Budeprion, Contrave, Forfivo, Wellbutrin, Zyban •Brand Names (Drug B): Demser •Synonyms (Drug A): No synonyms listed •Synonyms (Drug B): (S)-alpha-Methyltyrosine Methyltyrosine Metirosin Metirosina Metirosine Métirosine Metirosinum Metyrosine •Summary (Drug A): Bupropion is a norepinephrine and dopamine reuptake inhibitor used in the treatment of major depressive disorder (MDD), seasonal affective disorder (SAD), and as an aid to smoking cessation. •Summary (Drug B): Metyrosine is a tyrosine 3-monooxygenase inhibitor used to treat excessive sympathetic stimulation in pheochromocytoma.

Central nervous system depressants may potentiate the sedative effects of metyrosine, due to additive pharmacological effects. The severity of the interaction is moderate.

Question: Does Bupropion and Metyrosine interact? Information: •Drug A: Bupropion •Drug B: Metyrosine •Severity: MODERATE •Description: Bupropion may increase the sedative activities of Metyrosine. •Extended Description: Central nervous system depressants may potentiate the sedative effects of metyrosine, due to additive pharmacological effects. •Indication (Drug A): Bupropion is indicated for the treatment of major depressive disorder (MDD), seasonal affective disorder (SAD), and as an aid to smoking cessation. When used in combination with naltrexone as the marketed product ContraveⓇ, bupropion is indicated as an adjunct to a reduced-calorie diet and increased physical activity for chronic weight management in adults with an initial body mass index (BMI) of: 30 kg/m^2 or greater (obese) or 27 kg/m^2 or greater (overweight) in the presence of at least one weight-related comorbid condition (e.g., hypertension, type 2 diabetes mellitus, or dyslipidemia). Bupropion is also used off-label as a first-line treatment in patients with ADHD and comorbid bipolar disorder when used as an adjunct to mood stabilizers. •Indication (Drug B): For use in the treatment of patients with pheochromocytoma, for preoperative preparation of patients for surgery, management of patients when surgery is contraindicated, and chronic treatment of patients with malignant pheochromocytoma. •Pharmacodynamics (Drug A): Bupropion is chemically unrelated to tricyclic, tetracyclic, selective serotonin re-uptake inhibitors, or other known antidepressant agents. Compared to classical tricyclic antidepressants, Bupropion is a relatively weak inhibitor of the neuronal uptake of norepinephrine and dopamine. In addition, Bupropion does not inhibit monoamine oxidase. Bupropion has been found to be essentially inactive at the serotonin transporter (SERT)(IC50 >10 000 nM), however both bupropion and its primary metabolite hydroxybupropion have been found to block the function of cation-selective serotonin type 3A receptors (5-HT3ARs). Bupropion produces dose-related central nervous system (CNS) stimulant effects in animals, as evidenced by increased locomotor activity, increased rates of responding in various schedule-controlled operant behaviour tasks, and, at high doses, induction of mild stereotyped behaviour. Due to these stimulant effects and selective activity at dopamine and norepinephrine receptors, bupropion has been identified as having an abuse potential. Bupropion has a similar structure to the controlled substance Cathinone, and has been identified as having mild amphetamine-like activity, particularly when inhaled or injected. Bupropion is also known to lower the seizure threshold, making any pre-existing seizure conditions a contraindication to its use. This risk is exacerbated when bupropion is combined with other drugs or substances that lower the seizure threshold, such as cocaine, or in clinical situations that would increase the risk of a seizure such as abrupt alcohol or benzodiazepine withdrawal. As norepinephrine has been shown to have anticonvulsant properties, bupropion's inhibitory effects on NET are thought to contribute to its pro-convulsant activity. Bupropion has been shown to increase blood pressure and pose a risk for exacerbation of unmanaged or pre-existing hypertension, however, clinical trials of bupropion in smokers with CVD have not identified an increased incidence of CV events including stroke or heart attack. In clinical trials, the mean increase in systolic blood pressure associated with the use of bupropion was found to be 1.3 mmHg. •Pharmacodynamics (Drug B): In patients with pheochromocytoma, who produce excessive amounts of norepinephrine and epinephrine, administration of one to four grams of metyrosine per day has reduced catecholamine biosynthesis from about 35 to 80 percent as measured by the total excretion of catecholamines and their metabolites (metanephrine and vanillylmandelic acid). The maximum biochemical effect usually occurs within two to three days, and the urinary concentration of catecholamines and their metabolites usually returns to pretreatment levels within three to four days after metyrosine is discontinued. Most patients with pheochromocytoma treated with metyrosine experience decreased frequency and severity of hypertensive attacks with their associated headache, nausea, sweating, and tachycardia. In patients who respond, blood pressure decreases progressively during the first two days of therapy with metyrosine; after withdrawal, blood pressure usually increases gradually to pretreatment values within two to three days. •Mechanism of action (Drug A): Bupropion is a norepinephrine/dopamine-reuptake inhibitor (NDRI) that exerts its pharmacological effects by weakly inhibiting the enzymes involved in the uptake of the neurotransmitters norepinephrine and dopamine from the synaptic cleft, therefore prolonging their duration of action within the neuronal synapse and the downstream effects of these neurotransmitters. More specifically, bupropion binds to the norepinephrine transporter (NET) and the dopamine transporter (DAT). Bupropion was originally classified as an "atypical" antidepressant because it does not exert the same effects as the classical antidepressants such as Monoamine Oxidase Inhibitors (MAOIs), Tricyclic Antidepressants (TCAs), or Selective Serotonin Reuptake Inhibitors (SSRIs). While it has comparable effectiveness to typical first-line options for the treatment of depression such as SSRIs, bupropion is a unique option for the treatment of MDD as it lacks any clinically relevant serotonergic effects, typical of other mood medications, or any effects on histamine or adrenaline receptors. Lack of activity at these receptors results in a more tolerable side effect profile; bupropion is less likely to cause sexual side effects, sedation, or weight gain as compared to SSRIs or TCAs, for example. When used as an aid to smoking cessation, bupropion is thought to confer its anti-craving and anti-withdrawal effects by inhibiting dopamine reuptake, which is thought to be involved in the reward pathways associated with nicotine, and through the antagonism of the nicotinic acetylcholinergic receptor (AChR), thereby blunting the effects of nicotine. Furthermore, the stimulatory effects produced by bupropion in the central nervous system are similar to nicotine's effects, making low doses of bupropion a suitable option as a nicotine substitute. When used in combination with naltrexone in the marketed product ContraveⓇ for chronic weight management, the two components are thought to have effects on areas of the brain involved in the regulation of food intake. This includes the hypothalamus, which is involved in appetite regulation, and the mesolimbic dopamine circuit, which is involved in reward pathways. Studies have shown that the combined activity of bupropion and naltrexone increase the firing rate of hypothalamic pro-opiomelanocortin (POMC) neurons and blockade of opioid receptor-mediated POMC auto-inhibition, which are associated with a reduction in food intake and increased energy expenditure. This combination was also found to reduce food intake when injected directly into the ventral tegmental area of the mesolimbic circuit in mice, which is an area associated with the regulation of reward pathways. •Mechanism of action (Drug B): Metyrosine inhibits tyrosine hydroxylase, which catalyzes the first transformation in catecholamine biosynthesis, i.e., the conversion of tyrosine to dihydroxyphenylalanine (DOPA). Because the first step is also the rate-limiting step, blockade of tyrosine hydroxylase activity results in decreased endogenous levels of catecholamines and their synthesis. This consequently, depletes the levels of the catecholamines dopamine, adrenaline and noradrenaline in the body,usually measured as decreased urinary excretion of catecholamines and their metabolites. One main end result of the catecholamine depletion is a decrease in blood presure. •Absorption (Drug A): Bupropion is currently available in 3 distinct, but bioequivalent formulations: immediate release (IR), sustained-release (SR), and extended-release (XL). Immediate Release Formulation In humans, following oral administration of bupropion hydrochloride tablets, peak plasma bupropion concentrations are usually achieved within 2 hours. IR formulations provide a short duration of action and are therefore generally dosed three times per day. Sustained Release Formulation In humans, following oral administration of bupropion hydrochloride sustained-release tablets (SR), peak plasma concentration (Cmax) of bupropion is usually achieved within 3 hours. SR formulations provide a 12-hour extended release of medication and are therefore generally dosed twice per day. Extended Release Formulation Following single oral administration of bupropion hydrochloride extended-release tablets (XL) to healthy volunteers, the median time to peak plasma concentrations for bupropion was approximately 5 hours. The presence of food did not affect the peak concentration or area under the curve of bupropion. XL formulations provide a 24-hour extended release of medication and are therefore generally dosed once per day/ In a trial comparing chronic dosing with bupropion hydrochloride extended-release tablets (SR) 150 mg twice daily to bupropion immediate-release formulation 100 mg 3 times daily, the steady state Cmax for bupropion after bupropion hydrochloride sustained-release tablets (SR) administration was approximately 85% of those achieved after bupropion immediate-release formulation administration. Exposure (AUC) to bupropion was equivalent for both formulations. Bioequivalence was also demonstrated for all three major active metabolites (i.e., hydroxybupropion, threohydrobupropion and erythrohydrobupropion) for both Cmax and AUC. Thus, at steady state, bupropion hydrochloride sustained-release tablets (SR) given twice daily, and the immediate-release formulation of bupropion given 3 times daily, are essentially bioequivalent for both bupropion and the 3 quantitatively important metabolites. Furthermore, in a study comparing 14-day dosing with bupropion hydrochloride extended-release tablets (XL), 300 mg once-daily to the immediate-release formulation of bupropion at 100 mg 3 times daily, equivalence was demonstrated for peak plasma concentration and area under the curve for bupropion and the three metabolites (hydroxybupropion, threohydrobupropion, and erythrohydrobupropion). Additionally, in a study comparing 14-day dosing with bupropion hydrochloride extended-release tablets (XL) 300 mg once daily to the sustained-release formulation of bupropion at 150 mg 2 times daily, equivalence was demonstrated for peak plasma concentration and area under the curve for bupropion and the three metabolites. Bupropion hydrochloride extended-release tablets (SR) can be taken with or without food. Bupropion Cmax and AUC were increased by 11% to 35% and 16% to 19%, respectively, when bupropion hydrochloride extended-release tablets (SR) was administered with food to healthy volunteers in three trials. The food effect is not considered clinically significant. Following a single-dose administration of bupropion hydrochloride extended-release tablets (SR) in humans, Cmax of bupropion's metabolite hydroxybupropion occurs approximately 6 hours post-dose and is approximately 10 times the peak level of the parent drug at steady state. The elimination half-life of hydroxybupropion is approximately 20 (±5) hours and its AUC at steady state is about 17 times that of bupropion. The times to peak concentrations for the erythrohydrobupropion and threohydrobupropion metabolites are similar to that of the hydroxybupropion metabolite. However, their elimination half-lives are longer, 33(±10) and 37 (±13) hours, respectively, and steady-state AUCs are 1.5 and 7 times that of bupropion, respectively. •Absorption (Drug B): Well absorbed from the gastrointestinal tract. •Volume of distribution (Drug A): No volume of distribution available •Volume of distribution (Drug B): No volume of distribution available •Protein binding (Drug A): In vitro tests show that bupropion is 84% bound to human plasma proteins at concentrations up to 200 mcg per mL. The extent of protein binding of the hydroxybupropion metabolite is similar to that for bupropion, whereas the extent of protein binding of the threohydrobupropion metabolite is about half that seen with bupropion. •Protein binding (Drug B): No protein binding available •Metabolism (Drug A): Bupropion is extensively metabolized in humans. Three metabolites are active: hydroxybupropion, which is formed via hydroxylation of the tert-butyl group of bupropion, and the amino-alcohol isomers, threohydrobupropion and erythrohydrobupropion, which are formed via reduction of the carbonyl group. In vitro findings suggest that CYP2B6 is the principal isoenzyme involved in the formation of hydroxybupropion, while cytochrome P450 enzymes are not involved in the formation of threohydrobupropion. Hydroxybupropion has been shown to have the same affinity as bupropion for the norepinephrine transporter (NET) but approximately 50% of its antidepressant activity despite reaching concentrations of ~10-fold higher than that of the parent drug. Oxidation of the bupropion side chain results in the formation of a glycine conjugate of meta-chlorobenzoic acid, which is then excreted as the major urinary metabolite. The potency and toxicity of the metabolites relative to bupropion have not been fully characterized. However, it has been demonstrated in an antidepressant screening test in mice that hydroxybupropion is one-half as potent as bupropion, while threohydrobupropion and erythrohydrobupropion are 5-fold less potent than bupropion. This may be of clinical importance because the plasma concentrations of the metabolites are as high as or higher than those of bupropion. Bupropion and its metabolites exhibit linear kinetics following chronic administration of 300 to 450 mg per day. •Metabolism (Drug B): Little biotransformation, with catechol metabolites accounting for less than 1% of the administered dose. •Route of elimination (Drug A): Bupropion is extensively metabolized in humans. Oxidation of the bupropion side chain results in the formation of a glycine conjugate of metachlorobenzoic acid, which is then excreted as the major urinary metabolite. Following oral administration of 200 mg of 14C-bupropion in humans, 87% and 10% of the radioactive dose were recovered in the urine and feces, respectively. However, the fraction of the oral dose of bupropion excreted unchanged was only 0.5%, a finding consistent with the extensive metabolism of bupropion. •Route of elimination (Drug B): Because the first step is also the rate-limiting step, blockade of tyrosine hydroxylase activity results in decreased endogenous levels of catecholamines, usually measured as decreased urinary excretion of catecholamines and their metabolites. •Half-life (Drug A): 24 hours •Half-life (Drug B): 3.4 to 3.7 hours •Clearance (Drug A): No clearance available •Clearance (Drug B): No clearance available •Toxicity (Drug A): Symptoms of overdose include seizures, hallucinations, loss of consciousness, tachycardia, and cardiac arrest. •Toxicity (Drug B): Signs of metyrosine overdosage include those central nervous system effects observed in some patients even at low dosages. At doses exceeding 2000 mg/day, some degree of sedation or feeling of fatigue may persist. Doses of 2000-4000 mg/day can result in anxiety or agitated depression, neuromuscular effects (including fine tremor of the hands, gross tremor of the trunk, tightening of the jaw with trismus), diarrhea, and decreased salivation with dry mouth. The acute toxicity of metyrosine was 442 mg/kg and 752 mg/kg in the female mouse and rat respectively. •Brand Names (Drug A): Aplenzin, Auvelity, Budeprion, Contrave, Forfivo, Wellbutrin, Zyban •Brand Names (Drug B): Demser •Synonyms (Drug A): No synonyms listed •Synonyms (Drug B): (S)-alpha-Methyltyrosine Methyltyrosine Metirosin Metirosina Metirosine Métirosine Metirosinum Metyrosine •Summary (Drug A): Bupropion is a norepinephrine and dopamine reuptake inhibitor used in the treatment of major depressive disorder (MDD), seasonal affective disorder (SAD), and as an aid to smoking cessation. •Summary (Drug B): Metyrosine is a tyrosine 3-monooxygenase inhibitor used to treat excessive sympathetic stimulation in pheochromocytoma. Output: Central nervous system depressants may potentiate the sedative effects of metyrosine, due to additive pharmacological effects. The severity of the interaction is moderate.

Does Bupropion and Mexiletine interact?

•Drug A: Bupropion •Drug B: Mexiletine •Severity: MAJOR •Description: The metabolism of Mexiletine can be decreased when combined with Bupropion. •Extended Description: The subject drug is a strong CYP2D6 inhibitor and the affected drug is metabolized by CYP2D6. Concomitant administration may decrease the metabolism of the affected drug, which could increase serum concentrations as well as the risk and severity of adverse effects. •Indication (Drug A): Bupropion is indicated for the treatment of major depressive disorder (MDD), seasonal affective disorder (SAD), and as an aid to smoking cessation. When used in combination with naltrexone as the marketed product ContraveⓇ, bupropion is indicated as an adjunct to a reduced-calorie diet and increased physical activity for chronic weight management in adults with an initial body mass index (BMI) of: 30 kg/m^2 or greater (obese) or 27 kg/m^2 or greater (overweight) in the presence of at least one weight-related comorbid condition (e.g., hypertension, type 2 diabetes mellitus, or dyslipidemia). Bupropion is also used off-label as a first-line treatment in patients with ADHD and comorbid bipolar disorder when used as an adjunct to mood stabilizers. •Indication (Drug B): For the treatment of ventricular tachycardia and symptomatic premature ventricular beats, and prevention of ventricular fibrillation. •Pharmacodynamics (Drug A): Bupropion is chemically unrelated to tricyclic, tetracyclic, selective serotonin re-uptake inhibitors, or other known antidepressant agents. Compared to classical tricyclic antidepressants, Bupropion is a relatively weak inhibitor of the neuronal uptake of norepinephrine and dopamine. In addition, Bupropion does not inhibit monoamine oxidase. Bupropion has been found to be essentially inactive at the serotonin transporter (SERT)(IC50 >10 000 nM), however both bupropion and its primary metabolite hydroxybupropion have been found to block the function of cation-selective serotonin type 3A receptors (5-HT3ARs). Bupropion produces dose-related central nervous system (CNS) stimulant effects in animals, as evidenced by increased locomotor activity, increased rates of responding in various schedule-controlled operant behaviour tasks, and, at high doses, induction of mild stereotyped behaviour. Due to these stimulant effects and selective activity at dopamine and norepinephrine receptors, bupropion has been identified as having an abuse potential. Bupropion has a similar structure to the controlled substance Cathinone, and has been identified as having mild amphetamine-like activity, particularly when inhaled or injected. Bupropion is also known to lower the seizure threshold, making any pre-existing seizure conditions a contraindication to its use. This risk is exacerbated when bupropion is combined with other drugs or substances that lower the seizure threshold, such as cocaine, or in clinical situations that would increase the risk of a seizure such as abrupt alcohol or benzodiazepine withdrawal. As norepinephrine has been shown to have anticonvulsant properties, bupropion's inhibitory effects on NET are thought to contribute to its pro-convulsant activity. Bupropion has been shown to increase blood pressure and pose a risk for exacerbation of unmanaged or pre-existing hypertension, however, clinical trials of bupropion in smokers with CVD have not identified an increased incidence of CV events including stroke or heart attack. In clinical trials, the mean increase in systolic blood pressure associated with the use of bupropion was found to be 1.3 mmHg. •Pharmacodynamics (Drug B): Mexiletine is a local anesthetic, antiarrhythmic agent (Class Ib), structurally similar to lidocaine, but orally active. Mexiletine has fast onset and offset kinetics, meaning that they have little or no effect at slower heart rates, and more effects at faster heart rates. It shortens the action potential duration, reduces refractoriness, and decreases Vmax in partially depolarized cells with fast response action potentials. Mexiletine either does not change the action potential duration, or decreases the action potential duration. •Mechanism of action (Drug A): Bupropion is a norepinephrine/dopamine-reuptake inhibitor (NDRI) that exerts its pharmacological effects by weakly inhibiting the enzymes involved in the uptake of the neurotransmitters norepinephrine and dopamine from the synaptic cleft, therefore prolonging their duration of action within the neuronal synapse and the downstream effects of these neurotransmitters. More specifically, bupropion binds to the norepinephrine transporter (NET) and the dopamine transporter (DAT). Bupropion was originally classified as an "atypical" antidepressant because it does not exert the same effects as the classical antidepressants such as Monoamine Oxidase Inhibitors (MAOIs), Tricyclic Antidepressants (TCAs), or Selective Serotonin Reuptake Inhibitors (SSRIs). While it has comparable effectiveness to typical first-line options for the treatment of depression such as SSRIs, bupropion is a unique option for the treatment of MDD as it lacks any clinically relevant serotonergic effects, typical of other mood medications, or any effects on histamine or adrenaline receptors. Lack of activity at these receptors results in a more tolerable side effect profile; bupropion is less likely to cause sexual side effects, sedation, or weight gain as compared to SSRIs or TCAs, for example. When used as an aid to smoking cessation, bupropion is thought to confer its anti-craving and anti-withdrawal effects by inhibiting dopamine reuptake, which is thought to be involved in the reward pathways associated with nicotine, and through the antagonism of the nicotinic acetylcholinergic receptor (AChR), thereby blunting the effects of nicotine. Furthermore, the stimulatory effects produced by bupropion in the central nervous system are similar to nicotine's effects, making low doses of bupropion a suitable option as a nicotine substitute. When used in combination with naltrexone in the marketed product ContraveⓇ for chronic weight management, the two components are thought to have effects on areas of the brain involved in the regulation of food intake. This includes the hypothalamus, which is involved in appetite regulation, and the mesolimbic dopamine circuit, which is involved in reward pathways. Studies have shown that the combined activity of bupropion and naltrexone increase the firing rate of hypothalamic pro-opiomelanocortin (POMC) neurons and blockade of opioid receptor-mediated POMC auto-inhibition, which are associated with a reduction in food intake and increased energy expenditure. This combination was also found to reduce food intake when injected directly into the ventral tegmental area of the mesolimbic circuit in mice, which is an area associated with the regulation of reward pathways. •Mechanism of action (Drug B): Mexiletine, like lidocaine, inhibits the inward sodium current required for the initiation and conduction of impulses, thus reducing the rate of rise of the action potential, Phase 0. It achieves this reduced sodium current by inhibiting sodium channels. Mexiletine decreases the effective refractory period (ERP) in Purkinje fibers in the heart. The decrease in ERP is of lesser magnitude than the decrease in action potential duration (APD), which results in an increase in the ERP/APD ratio. It does not significantly affect resting membrane potential or sinus node automaticity, left ventricular function, systolic arterial blood pressure, atrioventricular (AV) conduction velocity, or QRS or QT intervals •Absorption (Drug A): Bupropion is currently available in 3 distinct, but bioequivalent formulations: immediate release (IR), sustained-release (SR), and extended-release (XL). Immediate Release Formulation In humans, following oral administration of bupropion hydrochloride tablets, peak plasma bupropion concentrations are usually achieved within 2 hours. IR formulations provide a short duration of action and are therefore generally dosed three times per day. Sustained Release Formulation In humans, following oral administration of bupropion hydrochloride sustained-release tablets (SR), peak plasma concentration (Cmax) of bupropion is usually achieved within 3 hours. SR formulations provide a 12-hour extended release of medication and are therefore generally dosed twice per day. Extended Release Formulation Following single oral administration of bupropion hydrochloride extended-release tablets (XL) to healthy volunteers, the median time to peak plasma concentrations for bupropion was approximately 5 hours. The presence of food did not affect the peak concentration or area under the curve of bupropion. XL formulations provide a 24-hour extended release of medication and are therefore generally dosed once per day/ In a trial comparing chronic dosing with bupropion hydrochloride extended-release tablets (SR) 150 mg twice daily to bupropion immediate-release formulation 100 mg 3 times daily, the steady state Cmax for bupropion after bupropion hydrochloride sustained-release tablets (SR) administration was approximately 85% of those achieved after bupropion immediate-release formulation administration. Exposure (AUC) to bupropion was equivalent for both formulations. Bioequivalence was also demonstrated for all three major active metabolites (i.e., hydroxybupropion, threohydrobupropion and erythrohydrobupropion) for both Cmax and AUC. Thus, at steady state, bupropion hydrochloride sustained-release tablets (SR) given twice daily, and the immediate-release formulation of bupropion given 3 times daily, are essentially bioequivalent for both bupropion and the 3 quantitatively important metabolites. Furthermore, in a study comparing 14-day dosing with bupropion hydrochloride extended-release tablets (XL), 300 mg once-daily to the immediate-release formulation of bupropion at 100 mg 3 times daily, equivalence was demonstrated for peak plasma concentration and area under the curve for bupropion and the three metabolites (hydroxybupropion, threohydrobupropion, and erythrohydrobupropion). Additionally, in a study comparing 14-day dosing with bupropion hydrochloride extended-release tablets (XL) 300 mg once daily to the sustained-release formulation of bupropion at 150 mg 2 times daily, equivalence was demonstrated for peak plasma concentration and area under the curve for bupropion and the three metabolites. Bupropion hydrochloride extended-release tablets (SR) can be taken with or without food. Bupropion Cmax and AUC were increased by 11% to 35% and 16% to 19%, respectively, when bupropion hydrochloride extended-release tablets (SR) was administered with food to healthy volunteers in three trials. The food effect is not considered clinically significant. Following a single-dose administration of bupropion hydrochloride extended-release tablets (SR) in humans, Cmax of bupropion's metabolite hydroxybupropion occurs approximately 6 hours post-dose and is approximately 10 times the peak level of the parent drug at steady state. The elimination half-life of hydroxybupropion is approximately 20 (±5) hours and its AUC at steady state is about 17 times that of bupropion. The times to peak concentrations for the erythrohydrobupropion and threohydrobupropion metabolites are similar to that of the hydroxybupropion metabolite. However, their elimination half-lives are longer, 33(±10) and 37 (±13) hours, respectively, and steady-state AUCs are 1.5 and 7 times that of bupropion, respectively. •Absorption (Drug B): Well absorbed (bioavailability 90%) from the gastrointenstinal tract. •Volume of distribution (Drug A): No volume of distribution available •Volume of distribution (Drug B): 5 to 7 L/lg •Protein binding (Drug A): In vitro tests show that bupropion is 84% bound to human plasma proteins at concentrations up to 200 mcg per mL. The extent of protein binding of the hydroxybupropion metabolite is similar to that for bupropion, whereas the extent of protein binding of the threohydrobupropion metabolite is about half that seen with bupropion. •Protein binding (Drug B): 50-60% •Metabolism (Drug A): Bupropion is extensively metabolized in humans. Three metabolites are active: hydroxybupropion, which is formed via hydroxylation of the tert-butyl group of bupropion, and the amino-alcohol isomers, threohydrobupropion and erythrohydrobupropion, which are formed via reduction of the carbonyl group. In vitro findings suggest that CYP2B6 is the principal isoenzyme involved in the formation of hydroxybupropion, while cytochrome P450 enzymes are not involved in the formation of threohydrobupropion. Hydroxybupropion has been shown to have the same affinity as bupropion for the norepinephrine transporter (NET) but approximately 50% of its antidepressant activity despite reaching concentrations of ~10-fold higher than that of the parent drug. Oxidation of the bupropion side chain results in the formation of a glycine conjugate of meta-chlorobenzoic acid, which is then excreted as the major urinary metabolite. The potency and toxicity of the metabolites relative to bupropion have not been fully characterized. However, it has been demonstrated in an antidepressant screening test in mice that hydroxybupropion is one-half as potent as bupropion, while threohydrobupropion and erythrohydrobupropion are 5-fold less potent than bupropion. This may be of clinical importance because the plasma concentrations of the metabolites are as high as or higher than those of bupropion. Bupropion and its metabolites exhibit linear kinetics following chronic administration of 300 to 450 mg per day. •Metabolism (Drug B): Primarily hepatic (85%) via CYP2D6 and CYP1A2 (primarily CYP2D6). •Route of elimination (Drug A): Bupropion is extensively metabolized in humans. Oxidation of the bupropion side chain results in the formation of a glycine conjugate of metachlorobenzoic acid, which is then excreted as the major urinary metabolite. Following oral administration of 200 mg of 14C-bupropion in humans, 87% and 10% of the radioactive dose were recovered in the urine and feces, respectively. However, the fraction of the oral dose of bupropion excreted unchanged was only 0.5%, a finding consistent with the extensive metabolism of bupropion. •Route of elimination (Drug B): Approximately 10% is excreted unchanged by the kidney. The urinary excretion of N-methylmexiletine in man is less than 0.5%. •Half-life (Drug A): 24 hours •Half-life (Drug B): 10-12 hours •Clearance (Drug A): No clearance available •Clearance (Drug B): No clearance available •Toxicity (Drug A): Symptoms of overdose include seizures, hallucinations, loss of consciousness, tachycardia, and cardiac arrest. •Toxicity (Drug B): Symptoms of overdose include nausea, hypotension, sinus bradycardia, paresthesia, seizures, bundle branch block, AV heart block, asystole, ventricular tachyarrythmia, including ventricular fibrillation, cardiovascular collapse, and coma. •Brand Names (Drug A): Aplenzin, Auvelity, Budeprion, Contrave, Forfivo, Wellbutrin, Zyban •Brand Names (Drug B): No brand names available •Synonyms (Drug A): No synonyms listed •Synonyms (Drug B): Mexiletina Mexilétine Mexiletine Mexiletinum •Summary (Drug A): Bupropion is a norepinephrine and dopamine reuptake inhibitor used in the treatment of major depressive disorder (MDD), seasonal affective disorder (SAD), and as an aid to smoking cessation. •Summary (Drug B): Mexiletine is a class 1B antiarrhythmic agent used in the treatment of documented ventricular arrhythmias that warrant treatment.

The subject drug is a strong CYP2D6 inhibitor and the affected drug is metabolized by CYP2D6. Concomitant administration may decrease the metabolism of the affected drug, which could increase serum concentrations as well as the risk and severity of adverse effects. The severity of the interaction is major.

Question: Does Bupropion and Mexiletine interact? Information: •Drug A: Bupropion •Drug B: Mexiletine •Severity: MAJOR •Description: The metabolism of Mexiletine can be decreased when combined with Bupropion. •Extended Description: The subject drug is a strong CYP2D6 inhibitor and the affected drug is metabolized by CYP2D6. Concomitant administration may decrease the metabolism of the affected drug, which could increase serum concentrations as well as the risk and severity of adverse effects. •Indication (Drug A): Bupropion is indicated for the treatment of major depressive disorder (MDD), seasonal affective disorder (SAD), and as an aid to smoking cessation. When used in combination with naltrexone as the marketed product ContraveⓇ, bupropion is indicated as an adjunct to a reduced-calorie diet and increased physical activity for chronic weight management in adults with an initial body mass index (BMI) of: 30 kg/m^2 or greater (obese) or 27 kg/m^2 or greater (overweight) in the presence of at least one weight-related comorbid condition (e.g., hypertension, type 2 diabetes mellitus, or dyslipidemia). Bupropion is also used off-label as a first-line treatment in patients with ADHD and comorbid bipolar disorder when used as an adjunct to mood stabilizers. •Indication (Drug B): For the treatment of ventricular tachycardia and symptomatic premature ventricular beats, and prevention of ventricular fibrillation. •Pharmacodynamics (Drug A): Bupropion is chemically unrelated to tricyclic, tetracyclic, selective serotonin re-uptake inhibitors, or other known antidepressant agents. Compared to classical tricyclic antidepressants, Bupropion is a relatively weak inhibitor of the neuronal uptake of norepinephrine and dopamine. In addition, Bupropion does not inhibit monoamine oxidase. Bupropion has been found to be essentially inactive at the serotonin transporter (SERT)(IC50 >10 000 nM), however both bupropion and its primary metabolite hydroxybupropion have been found to block the function of cation-selective serotonin type 3A receptors (5-HT3ARs). Bupropion produces dose-related central nervous system (CNS) stimulant effects in animals, as evidenced by increased locomotor activity, increased rates of responding in various schedule-controlled operant behaviour tasks, and, at high doses, induction of mild stereotyped behaviour. Due to these stimulant effects and selective activity at dopamine and norepinephrine receptors, bupropion has been identified as having an abuse potential. Bupropion has a similar structure to the controlled substance Cathinone, and has been identified as having mild amphetamine-like activity, particularly when inhaled or injected. Bupropion is also known to lower the seizure threshold, making any pre-existing seizure conditions a contraindication to its use. This risk is exacerbated when bupropion is combined with other drugs or substances that lower the seizure threshold, such as cocaine, or in clinical situations that would increase the risk of a seizure such as abrupt alcohol or benzodiazepine withdrawal. As norepinephrine has been shown to have anticonvulsant properties, bupropion's inhibitory effects on NET are thought to contribute to its pro-convulsant activity. Bupropion has been shown to increase blood pressure and pose a risk for exacerbation of unmanaged or pre-existing hypertension, however, clinical trials of bupropion in smokers with CVD have not identified an increased incidence of CV events including stroke or heart attack. In clinical trials, the mean increase in systolic blood pressure associated with the use of bupropion was found to be 1.3 mmHg. •Pharmacodynamics (Drug B): Mexiletine is a local anesthetic, antiarrhythmic agent (Class Ib), structurally similar to lidocaine, but orally active. Mexiletine has fast onset and offset kinetics, meaning that they have little or no effect at slower heart rates, and more effects at faster heart rates. It shortens the action potential duration, reduces refractoriness, and decreases Vmax in partially depolarized cells with fast response action potentials. Mexiletine either does not change the action potential duration, or decreases the action potential duration. •Mechanism of action (Drug A): Bupropion is a norepinephrine/dopamine-reuptake inhibitor (NDRI) that exerts its pharmacological effects by weakly inhibiting the enzymes involved in the uptake of the neurotransmitters norepinephrine and dopamine from the synaptic cleft, therefore prolonging their duration of action within the neuronal synapse and the downstream effects of these neurotransmitters. More specifically, bupropion binds to the norepinephrine transporter (NET) and the dopamine transporter (DAT). Bupropion was originally classified as an "atypical" antidepressant because it does not exert the same effects as the classical antidepressants such as Monoamine Oxidase Inhibitors (MAOIs), Tricyclic Antidepressants (TCAs), or Selective Serotonin Reuptake Inhibitors (SSRIs). While it has comparable effectiveness to typical first-line options for the treatment of depression such as SSRIs, bupropion is a unique option for the treatment of MDD as it lacks any clinically relevant serotonergic effects, typical of other mood medications, or any effects on histamine or adrenaline receptors. Lack of activity at these receptors results in a more tolerable side effect profile; bupropion is less likely to cause sexual side effects, sedation, or weight gain as compared to SSRIs or TCAs, for example. When used as an aid to smoking cessation, bupropion is thought to confer its anti-craving and anti-withdrawal effects by inhibiting dopamine reuptake, which is thought to be involved in the reward pathways associated with nicotine, and through the antagonism of the nicotinic acetylcholinergic receptor (AChR), thereby blunting the effects of nicotine. Furthermore, the stimulatory effects produced by bupropion in the central nervous system are similar to nicotine's effects, making low doses of bupropion a suitable option as a nicotine substitute. When used in combination with naltrexone in the marketed product ContraveⓇ for chronic weight management, the two components are thought to have effects on areas of the brain involved in the regulation of food intake. This includes the hypothalamus, which is involved in appetite regulation, and the mesolimbic dopamine circuit, which is involved in reward pathways. Studies have shown that the combined activity of bupropion and naltrexone increase the firing rate of hypothalamic pro-opiomelanocortin (POMC) neurons and blockade of opioid receptor-mediated POMC auto-inhibition, which are associated with a reduction in food intake and increased energy expenditure. This combination was also found to reduce food intake when injected directly into the ventral tegmental area of the mesolimbic circuit in mice, which is an area associated with the regulation of reward pathways. •Mechanism of action (Drug B): Mexiletine, like lidocaine, inhibits the inward sodium current required for the initiation and conduction of impulses, thus reducing the rate of rise of the action potential, Phase 0. It achieves this reduced sodium current by inhibiting sodium channels. Mexiletine decreases the effective refractory period (ERP) in Purkinje fibers in the heart. The decrease in ERP is of lesser magnitude than the decrease in action potential duration (APD), which results in an increase in the ERP/APD ratio. It does not significantly affect resting membrane potential or sinus node automaticity, left ventricular function, systolic arterial blood pressure, atrioventricular (AV) conduction velocity, or QRS or QT intervals •Absorption (Drug A): Bupropion is currently available in 3 distinct, but bioequivalent formulations: immediate release (IR), sustained-release (SR), and extended-release (XL). Immediate Release Formulation In humans, following oral administration of bupropion hydrochloride tablets, peak plasma bupropion concentrations are usually achieved within 2 hours. IR formulations provide a short duration of action and are therefore generally dosed three times per day. Sustained Release Formulation In humans, following oral administration of bupropion hydrochloride sustained-release tablets (SR), peak plasma concentration (Cmax) of bupropion is usually achieved within 3 hours. SR formulations provide a 12-hour extended release of medication and are therefore generally dosed twice per day. Extended Release Formulation Following single oral administration of bupropion hydrochloride extended-release tablets (XL) to healthy volunteers, the median time to peak plasma concentrations for bupropion was approximately 5 hours. The presence of food did not affect the peak concentration or area under the curve of bupropion. XL formulations provide a 24-hour extended release of medication and are therefore generally dosed once per day/ In a trial comparing chronic dosing with bupropion hydrochloride extended-release tablets (SR) 150 mg twice daily to bupropion immediate-release formulation 100 mg 3 times daily, the steady state Cmax for bupropion after bupropion hydrochloride sustained-release tablets (SR) administration was approximately 85% of those achieved after bupropion immediate-release formulation administration. Exposure (AUC) to bupropion was equivalent for both formulations. Bioequivalence was also demonstrated for all three major active metabolites (i.e., hydroxybupropion, threohydrobupropion and erythrohydrobupropion) for both Cmax and AUC. Thus, at steady state, bupropion hydrochloride sustained-release tablets (SR) given twice daily, and the immediate-release formulation of bupropion given 3 times daily, are essentially bioequivalent for both bupropion and the 3 quantitatively important metabolites. Furthermore, in a study comparing 14-day dosing with bupropion hydrochloride extended-release tablets (XL), 300 mg once-daily to the immediate-release formulation of bupropion at 100 mg 3 times daily, equivalence was demonstrated for peak plasma concentration and area under the curve for bupropion and the three metabolites (hydroxybupropion, threohydrobupropion, and erythrohydrobupropion). Additionally, in a study comparing 14-day dosing with bupropion hydrochloride extended-release tablets (XL) 300 mg once daily to the sustained-release formulation of bupropion at 150 mg 2 times daily, equivalence was demonstrated for peak plasma concentration and area under the curve for bupropion and the three metabolites. Bupropion hydrochloride extended-release tablets (SR) can be taken with or without food. Bupropion Cmax and AUC were increased by 11% to 35% and 16% to 19%, respectively, when bupropion hydrochloride extended-release tablets (SR) was administered with food to healthy volunteers in three trials. The food effect is not considered clinically significant. Following a single-dose administration of bupropion hydrochloride extended-release tablets (SR) in humans, Cmax of bupropion's metabolite hydroxybupropion occurs approximately 6 hours post-dose and is approximately 10 times the peak level of the parent drug at steady state. The elimination half-life of hydroxybupropion is approximately 20 (±5) hours and its AUC at steady state is about 17 times that of bupropion. The times to peak concentrations for the erythrohydrobupropion and threohydrobupropion metabolites are similar to that of the hydroxybupropion metabolite. However, their elimination half-lives are longer, 33(±10) and 37 (±13) hours, respectively, and steady-state AUCs are 1.5 and 7 times that of bupropion, respectively. •Absorption (Drug B): Well absorbed (bioavailability 90%) from the gastrointenstinal tract. •Volume of distribution (Drug A): No volume of distribution available •Volume of distribution (Drug B): 5 to 7 L/lg •Protein binding (Drug A): In vitro tests show that bupropion is 84% bound to human plasma proteins at concentrations up to 200 mcg per mL. The extent of protein binding of the hydroxybupropion metabolite is similar to that for bupropion, whereas the extent of protein binding of the threohydrobupropion metabolite is about half that seen with bupropion. •Protein binding (Drug B): 50-60% •Metabolism (Drug A): Bupropion is extensively metabolized in humans. Three metabolites are active: hydroxybupropion, which is formed via hydroxylation of the tert-butyl group of bupropion, and the amino-alcohol isomers, threohydrobupropion and erythrohydrobupropion, which are formed via reduction of the carbonyl group. In vitro findings suggest that CYP2B6 is the principal isoenzyme involved in the formation of hydroxybupropion, while cytochrome P450 enzymes are not involved in the formation of threohydrobupropion. Hydroxybupropion has been shown to have the same affinity as bupropion for the norepinephrine transporter (NET) but approximately 50% of its antidepressant activity despite reaching concentrations of ~10-fold higher than that of the parent drug. Oxidation of the bupropion side chain results in the formation of a glycine conjugate of meta-chlorobenzoic acid, which is then excreted as the major urinary metabolite. The potency and toxicity of the metabolites relative to bupropion have not been fully characterized. However, it has been demonstrated in an antidepressant screening test in mice that hydroxybupropion is one-half as potent as bupropion, while threohydrobupropion and erythrohydrobupropion are 5-fold less potent than bupropion. This may be of clinical importance because the plasma concentrations of the metabolites are as high as or higher than those of bupropion. Bupropion and its metabolites exhibit linear kinetics following chronic administration of 300 to 450 mg per day. •Metabolism (Drug B): Primarily hepatic (85%) via CYP2D6 and CYP1A2 (primarily CYP2D6). •Route of elimination (Drug A): Bupropion is extensively metabolized in humans. Oxidation of the bupropion side chain results in the formation of a glycine conjugate of metachlorobenzoic acid, which is then excreted as the major urinary metabolite. Following oral administration of 200 mg of 14C-bupropion in humans, 87% and 10% of the radioactive dose were recovered in the urine and feces, respectively. However, the fraction of the oral dose of bupropion excreted unchanged was only 0.5%, a finding consistent with the extensive metabolism of bupropion. •Route of elimination (Drug B): Approximately 10% is excreted unchanged by the kidney. The urinary excretion of N-methylmexiletine in man is less than 0.5%. •Half-life (Drug A): 24 hours •Half-life (Drug B): 10-12 hours •Clearance (Drug A): No clearance available •Clearance (Drug B): No clearance available •Toxicity (Drug A): Symptoms of overdose include seizures, hallucinations, loss of consciousness, tachycardia, and cardiac arrest. •Toxicity (Drug B): Symptoms of overdose include nausea, hypotension, sinus bradycardia, paresthesia, seizures, bundle branch block, AV heart block, asystole, ventricular tachyarrythmia, including ventricular fibrillation, cardiovascular collapse, and coma. •Brand Names (Drug A): Aplenzin, Auvelity, Budeprion, Contrave, Forfivo, Wellbutrin, Zyban •Brand Names (Drug B): No brand names available •Synonyms (Drug A): No synonyms listed •Synonyms (Drug B): Mexiletina Mexilétine Mexiletine Mexiletinum •Summary (Drug A): Bupropion is a norepinephrine and dopamine reuptake inhibitor used in the treatment of major depressive disorder (MDD), seasonal affective disorder (SAD), and as an aid to smoking cessation. •Summary (Drug B): Mexiletine is a class 1B antiarrhythmic agent used in the treatment of documented ventricular arrhythmias that warrant treatment. Output: The subject drug is a strong CYP2D6 inhibitor and the affected drug is metabolized by CYP2D6. Concomitant administration may decrease the metabolism of the affected drug, which could increase serum concentrations as well as the risk and severity of adverse effects. The severity of the interaction is major.

Does Bupropion and Mianserin interact?

•Drug A: Bupropion •Drug B: Mianserin •Severity: MAJOR •Description: The metabolism of Mianserin can be decreased when combined with Bupropion. •Extended Description: The subject drug is a strong CYP2D6 inhibitor and the affected drug is metabolized by CYP2D6. Concomitant administration may decrease the metabolism of the affected drug, which could increase serum concentrations as well as the risk and severity of adverse effects. •Indication (Drug A): Bupropion is indicated for the treatment of major depressive disorder (MDD), seasonal affective disorder (SAD), and as an aid to smoking cessation. When used in combination with naltrexone as the marketed product ContraveⓇ, bupropion is indicated as an adjunct to a reduced-calorie diet and increased physical activity for chronic weight management in adults with an initial body mass index (BMI) of: 30 kg/m^2 or greater (obese) or 27 kg/m^2 or greater (overweight) in the presence of at least one weight-related comorbid condition (e.g., hypertension, type 2 diabetes mellitus, or dyslipidemia). Bupropion is also used off-label as a first-line treatment in patients with ADHD and comorbid bipolar disorder when used as an adjunct to mood stabilizers. •Indication (Drug B): For the treatment of depression. •Pharmacodynamics (Drug A): Bupropion is chemically unrelated to tricyclic, tetracyclic, selective serotonin re-uptake inhibitors, or other known antidepressant agents. Compared to classical tricyclic antidepressants, Bupropion is a relatively weak inhibitor of the neuronal uptake of norepinephrine and dopamine. In addition, Bupropion does not inhibit monoamine oxidase. Bupropion has been found to be essentially inactive at the serotonin transporter (SERT)(IC50 >10 000 nM), however both bupropion and its primary metabolite hydroxybupropion have been found to block the function of cation-selective serotonin type 3A receptors (5-HT3ARs). Bupropion produces dose-related central nervous system (CNS) stimulant effects in animals, as evidenced by increased locomotor activity, increased rates of responding in various schedule-controlled operant behaviour tasks, and, at high doses, induction of mild stereotyped behaviour. Due to these stimulant effects and selective activity at dopamine and norepinephrine receptors, bupropion has been identified as having an abuse potential. Bupropion has a similar structure to the controlled substance Cathinone, and has been identified as having mild amphetamine-like activity, particularly when inhaled or injected. Bupropion is also known to lower the seizure threshold, making any pre-existing seizure conditions a contraindication to its use. This risk is exacerbated when bupropion is combined with other drugs or substances that lower the seizure threshold, such as cocaine, or in clinical situations that would increase the risk of a seizure such as abrupt alcohol or benzodiazepine withdrawal. As norepinephrine has been shown to have anticonvulsant properties, bupropion's inhibitory effects on NET are thought to contribute to its pro-convulsant activity. Bupropion has been shown to increase blood pressure and pose a risk for exacerbation of unmanaged or pre-existing hypertension, however, clinical trials of bupropion in smokers with CVD have not identified an increased incidence of CV events including stroke or heart attack. In clinical trials, the mean increase in systolic blood pressure associated with the use of bupropion was found to be 1.3 mmHg. •Pharmacodynamics (Drug B): Mianserin is a tetracyclic antidepressant that has antihistaminic and hypnosedative, but almost no anticholinergic, effect. It is a weak inhibitor of norepinephrine reuptake and strongly stimulates the release of norepinephrine. Interactions with serotonin receptors in the central nervous system have also been found. Its effect is usually noticeable after one to three weeks. Mianserin may cause drowsiness and hematological problems. •Mechanism of action (Drug A): Bupropion is a norepinephrine/dopamine-reuptake inhibitor (NDRI) that exerts its pharmacological effects by weakly inhibiting the enzymes involved in the uptake of the neurotransmitters norepinephrine and dopamine from the synaptic cleft, therefore prolonging their duration of action within the neuronal synapse and the downstream effects of these neurotransmitters. More specifically, bupropion binds to the norepinephrine transporter (NET) and the dopamine transporter (DAT). Bupropion was originally classified as an "atypical" antidepressant because it does not exert the same effects as the classical antidepressants such as Monoamine Oxidase Inhibitors (MAOIs), Tricyclic Antidepressants (TCAs), or Selective Serotonin Reuptake Inhibitors (SSRIs). While it has comparable effectiveness to typical first-line options for the treatment of depression such as SSRIs, bupropion is a unique option for the treatment of MDD as it lacks any clinically relevant serotonergic effects, typical of other mood medications, or any effects on histamine or adrenaline receptors. Lack of activity at these receptors results in a more tolerable side effect profile; bupropion is less likely to cause sexual side effects, sedation, or weight gain as compared to SSRIs or TCAs, for example. When used as an aid to smoking cessation, bupropion is thought to confer its anti-craving and anti-withdrawal effects by inhibiting dopamine reuptake, which is thought to be involved in the reward pathways associated with nicotine, and through the antagonism of the nicotinic acetylcholinergic receptor (AChR), thereby blunting the effects of nicotine. Furthermore, the stimulatory effects produced by bupropion in the central nervous system are similar to nicotine's effects, making low doses of bupropion a suitable option as a nicotine substitute. When used in combination with naltrexone in the marketed product ContraveⓇ for chronic weight management, the two components are thought to have effects on areas of the brain involved in the regulation of food intake. This includes the hypothalamus, which is involved in appetite regulation, and the mesolimbic dopamine circuit, which is involved in reward pathways. Studies have shown that the combined activity of bupropion and naltrexone increase the firing rate of hypothalamic pro-opiomelanocortin (POMC) neurons and blockade of opioid receptor-mediated POMC auto-inhibition, which are associated with a reduction in food intake and increased energy expenditure. This combination was also found to reduce food intake when injected directly into the ventral tegmental area of the mesolimbic circuit in mice, which is an area associated with the regulation of reward pathways. •Mechanism of action (Drug B): Mianserin's mechanism of therapeutic action is not well understood, although it apparently blocks alpha-adrenergic, histamine H1, and some types of serotonin receptors. •Absorption (Drug A): Bupropion is currently available in 3 distinct, but bioequivalent formulations: immediate release (IR), sustained-release (SR), and extended-release (XL). Immediate Release Formulation In humans, following oral administration of bupropion hydrochloride tablets, peak plasma bupropion concentrations are usually achieved within 2 hours. IR formulations provide a short duration of action and are therefore generally dosed three times per day. Sustained Release Formulation In humans, following oral administration of bupropion hydrochloride sustained-release tablets (SR), peak plasma concentration (Cmax) of bupropion is usually achieved within 3 hours. SR formulations provide a 12-hour extended release of medication and are therefore generally dosed twice per day. Extended Release Formulation Following single oral administration of bupropion hydrochloride extended-release tablets (XL) to healthy volunteers, the median time to peak plasma concentrations for bupropion was approximately 5 hours. The presence of food did not affect the peak concentration or area under the curve of bupropion. XL formulations provide a 24-hour extended release of medication and are therefore generally dosed once per day/ In a trial comparing chronic dosing with bupropion hydrochloride extended-release tablets (SR) 150 mg twice daily to bupropion immediate-release formulation 100 mg 3 times daily, the steady state Cmax for bupropion after bupropion hydrochloride sustained-release tablets (SR) administration was approximately 85% of those achieved after bupropion immediate-release formulation administration. Exposure (AUC) to bupropion was equivalent for both formulations. Bioequivalence was also demonstrated for all three major active metabolites (i.e., hydroxybupropion, threohydrobupropion and erythrohydrobupropion) for both Cmax and AUC. Thus, at steady state, bupropion hydrochloride sustained-release tablets (SR) given twice daily, and the immediate-release formulation of bupropion given 3 times daily, are essentially bioequivalent for both bupropion and the 3 quantitatively important metabolites. Furthermore, in a study comparing 14-day dosing with bupropion hydrochloride extended-release tablets (XL), 300 mg once-daily to the immediate-release formulation of bupropion at 100 mg 3 times daily, equivalence was demonstrated for peak plasma concentration and area under the curve for bupropion and the three metabolites (hydroxybupropion, threohydrobupropion, and erythrohydrobupropion). Additionally, in a study comparing 14-day dosing with bupropion hydrochloride extended-release tablets (XL) 300 mg once daily to the sustained-release formulation of bupropion at 150 mg 2 times daily, equivalence was demonstrated for peak plasma concentration and area under the curve for bupropion and the three metabolites. Bupropion hydrochloride extended-release tablets (SR) can be taken with or without food. Bupropion Cmax and AUC were increased by 11% to 35% and 16% to 19%, respectively, when bupropion hydrochloride extended-release tablets (SR) was administered with food to healthy volunteers in three trials. The food effect is not considered clinically significant. Following a single-dose administration of bupropion hydrochloride extended-release tablets (SR) in humans, Cmax of bupropion's metabolite hydroxybupropion occurs approximately 6 hours post-dose and is approximately 10 times the peak level of the parent drug at steady state. The elimination half-life of hydroxybupropion is approximately 20 (±5) hours and its AUC at steady state is about 17 times that of bupropion. The times to peak concentrations for the erythrohydrobupropion and threohydrobupropion metabolites are similar to that of the hydroxybupropion metabolite. However, their elimination half-lives are longer, 33(±10) and 37 (±13) hours, respectively, and steady-state AUCs are 1.5 and 7 times that of bupropion, respectively. •Absorption (Drug B): Absorbed following oral administration. •Volume of distribution (Drug A): No volume of distribution available •Volume of distribution (Drug B): No volume of distribution available •Protein binding (Drug A): In vitro tests show that bupropion is 84% bound to human plasma proteins at concentrations up to 200 mcg per mL. The extent of protein binding of the hydroxybupropion metabolite is similar to that for bupropion, whereas the extent of protein binding of the threohydrobupropion metabolite is about half that seen with bupropion. •Protein binding (Drug B): 90% •Metabolism (Drug A): Bupropion is extensively metabolized in humans. Three metabolites are active: hydroxybupropion, which is formed via hydroxylation of the tert-butyl group of bupropion, and the amino-alcohol isomers, threohydrobupropion and erythrohydrobupropion, which are formed via reduction of the carbonyl group. In vitro findings suggest that CYP2B6 is the principal isoenzyme involved in the formation of hydroxybupropion, while cytochrome P450 enzymes are not involved in the formation of threohydrobupropion. Hydroxybupropion has been shown to have the same affinity as bupropion for the norepinephrine transporter (NET) but approximately 50% of its antidepressant activity despite reaching concentrations of ~10-fold higher than that of the parent drug. Oxidation of the bupropion side chain results in the formation of a glycine conjugate of meta-chlorobenzoic acid, which is then excreted as the major urinary metabolite. The potency and toxicity of the metabolites relative to bupropion have not been fully characterized. However, it has been demonstrated in an antidepressant screening test in mice that hydroxybupropion is one-half as potent as bupropion, while threohydrobupropion and erythrohydrobupropion are 5-fold less potent than bupropion. This may be of clinical importance because the plasma concentrations of the metabolites are as high as or higher than those of bupropion. Bupropion and its metabolites exhibit linear kinetics following chronic administration of 300 to 450 mg per day. •Metabolism (Drug B): Hepatic. •Route of elimination (Drug A): Bupropion is extensively metabolized in humans. Oxidation of the bupropion side chain results in the formation of a glycine conjugate of metachlorobenzoic acid, which is then excreted as the major urinary metabolite. Following oral administration of 200 mg of 14C-bupropion in humans, 87% and 10% of the radioactive dose were recovered in the urine and feces, respectively. However, the fraction of the oral dose of bupropion excreted unchanged was only 0.5%, a finding consistent with the extensive metabolism of bupropion. •Route of elimination (Drug B): No route of elimination available •Half-life (Drug A): 24 hours •Half-life (Drug B): 10-17 hours •Clearance (Drug A): No clearance available •Clearance (Drug B): No clearance available •Toxicity (Drug A): Symptoms of overdose include seizures, hallucinations, loss of consciousness, tachycardia, and cardiac arrest. •Toxicity (Drug B): Oral rat LD 50: 780mg/kg •Brand Names (Drug A): Aplenzin, Auvelity, Budeprion, Contrave, Forfivo, Wellbutrin, Zyban •Brand Names (Drug B): No brand names available •Synonyms (Drug A): No synonyms listed •Synonyms (Drug B): Mianserin Mianserina Mianserine Miansérine Mianserinum Mianseryna •Summary (Drug A): Bupropion is a norepinephrine and dopamine reuptake inhibitor used in the treatment of major depressive disorder (MDD), seasonal affective disorder (SAD), and as an aid to smoking cessation. •Summary (Drug B): Mianserin is a tetracyclic antidepressant with therapeutic activity similar to amitriptyline used to treat depression and anxiety.

The subject drug is a strong CYP2D6 inhibitor and the affected drug is metabolized by CYP2D6. Concomitant administration may decrease the metabolism of the affected drug, which could increase serum concentrations as well as the risk and severity of adverse effects. The severity of the interaction is major.

Question: Does Bupropion and Mianserin interact? Information: •Drug A: Bupropion •Drug B: Mianserin •Severity: MAJOR •Description: The metabolism of Mianserin can be decreased when combined with Bupropion. •Extended Description: The subject drug is a strong CYP2D6 inhibitor and the affected drug is metabolized by CYP2D6. Concomitant administration may decrease the metabolism of the affected drug, which could increase serum concentrations as well as the risk and severity of adverse effects. •Indication (Drug A): Bupropion is indicated for the treatment of major depressive disorder (MDD), seasonal affective disorder (SAD), and as an aid to smoking cessation. When used in combination with naltrexone as the marketed product ContraveⓇ, bupropion is indicated as an adjunct to a reduced-calorie diet and increased physical activity for chronic weight management in adults with an initial body mass index (BMI) of: 30 kg/m^2 or greater (obese) or 27 kg/m^2 or greater (overweight) in the presence of at least one weight-related comorbid condition (e.g., hypertension, type 2 diabetes mellitus, or dyslipidemia). Bupropion is also used off-label as a first-line treatment in patients with ADHD and comorbid bipolar disorder when used as an adjunct to mood stabilizers. •Indication (Drug B): For the treatment of depression. •Pharmacodynamics (Drug A): Bupropion is chemically unrelated to tricyclic, tetracyclic, selective serotonin re-uptake inhibitors, or other known antidepressant agents. Compared to classical tricyclic antidepressants, Bupropion is a relatively weak inhibitor of the neuronal uptake of norepinephrine and dopamine. In addition, Bupropion does not inhibit monoamine oxidase. Bupropion has been found to be essentially inactive at the serotonin transporter (SERT)(IC50 >10 000 nM), however both bupropion and its primary metabolite hydroxybupropion have been found to block the function of cation-selective serotonin type 3A receptors (5-HT3ARs). Bupropion produces dose-related central nervous system (CNS) stimulant effects in animals, as evidenced by increased locomotor activity, increased rates of responding in various schedule-controlled operant behaviour tasks, and, at high doses, induction of mild stereotyped behaviour. Due to these stimulant effects and selective activity at dopamine and norepinephrine receptors, bupropion has been identified as having an abuse potential. Bupropion has a similar structure to the controlled substance Cathinone, and has been identified as having mild amphetamine-like activity, particularly when inhaled or injected. Bupropion is also known to lower the seizure threshold, making any pre-existing seizure conditions a contraindication to its use. This risk is exacerbated when bupropion is combined with other drugs or substances that lower the seizure threshold, such as cocaine, or in clinical situations that would increase the risk of a seizure such as abrupt alcohol or benzodiazepine withdrawal. As norepinephrine has been shown to have anticonvulsant properties, bupropion's inhibitory effects on NET are thought to contribute to its pro-convulsant activity. Bupropion has been shown to increase blood pressure and pose a risk for exacerbation of unmanaged or pre-existing hypertension, however, clinical trials of bupropion in smokers with CVD have not identified an increased incidence of CV events including stroke or heart attack. In clinical trials, the mean increase in systolic blood pressure associated with the use of bupropion was found to be 1.3 mmHg. •Pharmacodynamics (Drug B): Mianserin is a tetracyclic antidepressant that has antihistaminic and hypnosedative, but almost no anticholinergic, effect. It is a weak inhibitor of norepinephrine reuptake and strongly stimulates the release of norepinephrine. Interactions with serotonin receptors in the central nervous system have also been found. Its effect is usually noticeable after one to three weeks. Mianserin may cause drowsiness and hematological problems. •Mechanism of action (Drug A): Bupropion is a norepinephrine/dopamine-reuptake inhibitor (NDRI) that exerts its pharmacological effects by weakly inhibiting the enzymes involved in the uptake of the neurotransmitters norepinephrine and dopamine from the synaptic cleft, therefore prolonging their duration of action within the neuronal synapse and the downstream effects of these neurotransmitters. More specifically, bupropion binds to the norepinephrine transporter (NET) and the dopamine transporter (DAT). Bupropion was originally classified as an "atypical" antidepressant because it does not exert the same effects as the classical antidepressants such as Monoamine Oxidase Inhibitors (MAOIs), Tricyclic Antidepressants (TCAs), or Selective Serotonin Reuptake Inhibitors (SSRIs). While it has comparable effectiveness to typical first-line options for the treatment of depression such as SSRIs, bupropion is a unique option for the treatment of MDD as it lacks any clinically relevant serotonergic effects, typical of other mood medications, or any effects on histamine or adrenaline receptors. Lack of activity at these receptors results in a more tolerable side effect profile; bupropion is less likely to cause sexual side effects, sedation, or weight gain as compared to SSRIs or TCAs, for example. When used as an aid to smoking cessation, bupropion is thought to confer its anti-craving and anti-withdrawal effects by inhibiting dopamine reuptake, which is thought to be involved in the reward pathways associated with nicotine, and through the antagonism of the nicotinic acetylcholinergic receptor (AChR), thereby blunting the effects of nicotine. Furthermore, the stimulatory effects produced by bupropion in the central nervous system are similar to nicotine's effects, making low doses of bupropion a suitable option as a nicotine substitute. When used in combination with naltrexone in the marketed product ContraveⓇ for chronic weight management, the two components are thought to have effects on areas of the brain involved in the regulation of food intake. This includes the hypothalamus, which is involved in appetite regulation, and the mesolimbic dopamine circuit, which is involved in reward pathways. Studies have shown that the combined activity of bupropion and naltrexone increase the firing rate of hypothalamic pro-opiomelanocortin (POMC) neurons and blockade of opioid receptor-mediated POMC auto-inhibition, which are associated with a reduction in food intake and increased energy expenditure. This combination was also found to reduce food intake when injected directly into the ventral tegmental area of the mesolimbic circuit in mice, which is an area associated with the regulation of reward pathways. •Mechanism of action (Drug B): Mianserin's mechanism of therapeutic action is not well understood, although it apparently blocks alpha-adrenergic, histamine H1, and some types of serotonin receptors. •Absorption (Drug A): Bupropion is currently available in 3 distinct, but bioequivalent formulations: immediate release (IR), sustained-release (SR), and extended-release (XL). Immediate Release Formulation In humans, following oral administration of bupropion hydrochloride tablets, peak plasma bupropion concentrations are usually achieved within 2 hours. IR formulations provide a short duration of action and are therefore generally dosed three times per day. Sustained Release Formulation In humans, following oral administration of bupropion hydrochloride sustained-release tablets (SR), peak plasma concentration (Cmax) of bupropion is usually achieved within 3 hours. SR formulations provide a 12-hour extended release of medication and are therefore generally dosed twice per day. Extended Release Formulation Following single oral administration of bupropion hydrochloride extended-release tablets (XL) to healthy volunteers, the median time to peak plasma concentrations for bupropion was approximately 5 hours. The presence of food did not affect the peak concentration or area under the curve of bupropion. XL formulations provide a 24-hour extended release of medication and are therefore generally dosed once per day/ In a trial comparing chronic dosing with bupropion hydrochloride extended-release tablets (SR) 150 mg twice daily to bupropion immediate-release formulation 100 mg 3 times daily, the steady state Cmax for bupropion after bupropion hydrochloride sustained-release tablets (SR) administration was approximately 85% of those achieved after bupropion immediate-release formulation administration. Exposure (AUC) to bupropion was equivalent for both formulations. Bioequivalence was also demonstrated for all three major active metabolites (i.e., hydroxybupropion, threohydrobupropion and erythrohydrobupropion) for both Cmax and AUC. Thus, at steady state, bupropion hydrochloride sustained-release tablets (SR) given twice daily, and the immediate-release formulation of bupropion given 3 times daily, are essentially bioequivalent for both bupropion and the 3 quantitatively important metabolites. Furthermore, in a study comparing 14-day dosing with bupropion hydrochloride extended-release tablets (XL), 300 mg once-daily to the immediate-release formulation of bupropion at 100 mg 3 times daily, equivalence was demonstrated for peak plasma concentration and area under the curve for bupropion and the three metabolites (hydroxybupropion, threohydrobupropion, and erythrohydrobupropion). Additionally, in a study comparing 14-day dosing with bupropion hydrochloride extended-release tablets (XL) 300 mg once daily to the sustained-release formulation of bupropion at 150 mg 2 times daily, equivalence was demonstrated for peak plasma concentration and area under the curve for bupropion and the three metabolites. Bupropion hydrochloride extended-release tablets (SR) can be taken with or without food. Bupropion Cmax and AUC were increased by 11% to 35% and 16% to 19%, respectively, when bupropion hydrochloride extended-release tablets (SR) was administered with food to healthy volunteers in three trials. The food effect is not considered clinically significant. Following a single-dose administration of bupropion hydrochloride extended-release tablets (SR) in humans, Cmax of bupropion's metabolite hydroxybupropion occurs approximately 6 hours post-dose and is approximately 10 times the peak level of the parent drug at steady state. The elimination half-life of hydroxybupropion is approximately 20 (±5) hours and its AUC at steady state is about 17 times that of bupropion. The times to peak concentrations for the erythrohydrobupropion and threohydrobupropion metabolites are similar to that of the hydroxybupropion metabolite. However, their elimination half-lives are longer, 33(±10) and 37 (±13) hours, respectively, and steady-state AUCs are 1.5 and 7 times that of bupropion, respectively. •Absorption (Drug B): Absorbed following oral administration. •Volume of distribution (Drug A): No volume of distribution available •Volume of distribution (Drug B): No volume of distribution available •Protein binding (Drug A): In vitro tests show that bupropion is 84% bound to human plasma proteins at concentrations up to 200 mcg per mL. The extent of protein binding of the hydroxybupropion metabolite is similar to that for bupropion, whereas the extent of protein binding of the threohydrobupropion metabolite is about half that seen with bupropion. •Protein binding (Drug B): 90% •Metabolism (Drug A): Bupropion is extensively metabolized in humans. Three metabolites are active: hydroxybupropion, which is formed via hydroxylation of the tert-butyl group of bupropion, and the amino-alcohol isomers, threohydrobupropion and erythrohydrobupropion, which are formed via reduction of the carbonyl group. In vitro findings suggest that CYP2B6 is the principal isoenzyme involved in the formation of hydroxybupropion, while cytochrome P450 enzymes are not involved in the formation of threohydrobupropion. Hydroxybupropion has been shown to have the same affinity as bupropion for the norepinephrine transporter (NET) but approximately 50% of its antidepressant activity despite reaching concentrations of ~10-fold higher than that of the parent drug. Oxidation of the bupropion side chain results in the formation of a glycine conjugate of meta-chlorobenzoic acid, which is then excreted as the major urinary metabolite. The potency and toxicity of the metabolites relative to bupropion have not been fully characterized. However, it has been demonstrated in an antidepressant screening test in mice that hydroxybupropion is one-half as potent as bupropion, while threohydrobupropion and erythrohydrobupropion are 5-fold less potent than bupropion. This may be of clinical importance because the plasma concentrations of the metabolites are as high as or higher than those of bupropion. Bupropion and its metabolites exhibit linear kinetics following chronic administration of 300 to 450 mg per day. •Metabolism (Drug B): Hepatic. •Route of elimination (Drug A): Bupropion is extensively metabolized in humans. Oxidation of the bupropion side chain results in the formation of a glycine conjugate of metachlorobenzoic acid, which is then excreted as the major urinary metabolite. Following oral administration of 200 mg of 14C-bupropion in humans, 87% and 10% of the radioactive dose were recovered in the urine and feces, respectively. However, the fraction of the oral dose of bupropion excreted unchanged was only 0.5%, a finding consistent with the extensive metabolism of bupropion. •Route of elimination (Drug B): No route of elimination available •Half-life (Drug A): 24 hours •Half-life (Drug B): 10-17 hours •Clearance (Drug A): No clearance available •Clearance (Drug B): No clearance available •Toxicity (Drug A): Symptoms of overdose include seizures, hallucinations, loss of consciousness, tachycardia, and cardiac arrest. •Toxicity (Drug B): Oral rat LD 50: 780mg/kg •Brand Names (Drug A): Aplenzin, Auvelity, Budeprion, Contrave, Forfivo, Wellbutrin, Zyban •Brand Names (Drug B): No brand names available •Synonyms (Drug A): No synonyms listed •Synonyms (Drug B): Mianserin Mianserina Mianserine Miansérine Mianserinum Mianseryna •Summary (Drug A): Bupropion is a norepinephrine and dopamine reuptake inhibitor used in the treatment of major depressive disorder (MDD), seasonal affective disorder (SAD), and as an aid to smoking cessation. •Summary (Drug B): Mianserin is a tetracyclic antidepressant with therapeutic activity similar to amitriptyline used to treat depression and anxiety. Output: The subject drug is a strong CYP2D6 inhibitor and the affected drug is metabolized by CYP2D6. Concomitant administration may decrease the metabolism of the affected drug, which could increase serum concentrations as well as the risk and severity of adverse effects. The severity of the interaction is major.

Does Bupropion and Miconazole interact?

•Drug A: Bupropion •Drug B: Miconazole •Severity: MINOR •Description: The serum concentration of Bupropion can be increased when it is combined with Miconazole. •Extended Description: Bupropion is extensively metabolized to hydroxybupropion by CYP2B6. •Indication (Drug A): Bupropion is indicated for the treatment of major depressive disorder (MDD), seasonal affective disorder (SAD), and as an aid to smoking cessation. When used in combination with naltrexone as the marketed product ContraveⓇ, bupropion is indicated as an adjunct to a reduced-calorie diet and increased physical activity for chronic weight management in adults with an initial body mass index (BMI) of: 30 kg/m^2 or greater (obese) or 27 kg/m^2 or greater (overweight) in the presence of at least one weight-related comorbid condition (e.g., hypertension, type 2 diabetes mellitus, or dyslipidemia). Bupropion is also used off-label as a first-line treatment in patients with ADHD and comorbid bipolar disorder when used as an adjunct to mood stabilizers. •Indication (Drug B): Miconazole is indicated for the local treatment of oropharyngeal candidiasis in adult patients and for the adjunctive treatment of diaper dermatitis complicated by candidiasis in immunocompetent patients aged four weeks and older. Miconazole is available as both a suppository and cream for the treatment of vaginal yeast infections and the relief of associated vulvar itching and irritation. Lastly, miconazole cream is effective in treating athlete's foot (tinea pedis), jock itch (tinea cruris), ringworm infections (tinea corporis), pityriasis (formerly tinea) versicolor, and cutaneous candidiasis. •Pharmacodynamics (Drug A): Bupropion is chemically unrelated to tricyclic, tetracyclic, selective serotonin re-uptake inhibitors, or other known antidepressant agents. Compared to classical tricyclic antidepressants, Bupropion is a relatively weak inhibitor of the neuronal uptake of norepinephrine and dopamine. In addition, Bupropion does not inhibit monoamine oxidase. Bupropion has been found to be essentially inactive at the serotonin transporter (SERT)(IC50 >10 000 nM), however both bupropion and its primary metabolite hydroxybupropion have been found to block the function of cation-selective serotonin type 3A receptors (5-HT3ARs). Bupropion produces dose-related central nervous system (CNS) stimulant effects in animals, as evidenced by increased locomotor activity, increased rates of responding in various schedule-controlled operant behaviour tasks, and, at high doses, induction of mild stereotyped behaviour. Due to these stimulant effects and selective activity at dopamine and norepinephrine receptors, bupropion has been identified as having an abuse potential. Bupropion has a similar structure to the controlled substance Cathinone, and has been identified as having mild amphetamine-like activity, particularly when inhaled or injected. Bupropion is also known to lower the seizure threshold, making any pre-existing seizure conditions a contraindication to its use. This risk is exacerbated when bupropion is combined with other drugs or substances that lower the seizure threshold, such as cocaine, or in clinical situations that would increase the risk of a seizure such as abrupt alcohol or benzodiazepine withdrawal. As norepinephrine has been shown to have anticonvulsant properties, bupropion's inhibitory effects on NET are thought to contribute to its pro-convulsant activity. Bupropion has been shown to increase blood pressure and pose a risk for exacerbation of unmanaged or pre-existing hypertension, however, clinical trials of bupropion in smokers with CVD have not identified an increased incidence of CV events including stroke or heart attack. In clinical trials, the mean increase in systolic blood pressure associated with the use of bupropion was found to be 1.3 mmHg. •Pharmacodynamics (Drug B): Miconazole is an azole antifungal that functions primarily through inhibition of a specific demethylase within the CYP450 complex. As miconazole is typically applied topically and is minimally absorbed into the systemic circulation following application, the majority of patient reactions are limited to hypersensitivity and cases of anaphylaxis. Patients using intravaginal miconazole products are advised not to rely on contraceptives to prevent pregnancy and sexually transmitted infections, as well as not to use tampons concurrently. •Mechanism of action (Drug A): Bupropion is a norepinephrine/dopamine-reuptake inhibitor (NDRI) that exerts its pharmacological effects by weakly inhibiting the enzymes involved in the uptake of the neurotransmitters norepinephrine and dopamine from the synaptic cleft, therefore prolonging their duration of action within the neuronal synapse and the downstream effects of these neurotransmitters. More specifically, bupropion binds to the norepinephrine transporter (NET) and the dopamine transporter (DAT). Bupropion was originally classified as an "atypical" antidepressant because it does not exert the same effects as the classical antidepressants such as Monoamine Oxidase Inhibitors (MAOIs), Tricyclic Antidepressants (TCAs), or Selective Serotonin Reuptake Inhibitors (SSRIs). While it has comparable effectiveness to typical first-line options for the treatment of depression such as SSRIs, bupropion is a unique option for the treatment of MDD as it lacks any clinically relevant serotonergic effects, typical of other mood medications, or any effects on histamine or adrenaline receptors. Lack of activity at these receptors results in a more tolerable side effect profile; bupropion is less likely to cause sexual side effects, sedation, or weight gain as compared to SSRIs or TCAs, for example. When used as an aid to smoking cessation, bupropion is thought to confer its anti-craving and anti-withdrawal effects by inhibiting dopamine reuptake, which is thought to be involved in the reward pathways associated with nicotine, and through the antagonism of the nicotinic acetylcholinergic receptor (AChR), thereby blunting the effects of nicotine. Furthermore, the stimulatory effects produced by bupropion in the central nervous system are similar to nicotine's effects, making low doses of bupropion a suitable option as a nicotine substitute. When used in combination with naltrexone in the marketed product ContraveⓇ for chronic weight management, the two components are thought to have effects on areas of the brain involved in the regulation of food intake. This includes the hypothalamus, which is involved in appetite regulation, and the mesolimbic dopamine circuit, which is involved in reward pathways. Studies have shown that the combined activity of bupropion and naltrexone increase the firing rate of hypothalamic pro-opiomelanocortin (POMC) neurons and blockade of opioid receptor-mediated POMC auto-inhibition, which are associated with a reduction in food intake and increased energy expenditure. This combination was also found to reduce food intake when injected directly into the ventral tegmental area of the mesolimbic circuit in mice, which is an area associated with the regulation of reward pathways. •Mechanism of action (Drug B): Miconazole is an azole antifungal used to treat a variety of conditions, including those caused by Candida overgrowth. Unique among the azoles, miconazole is thought to act through three main mechanisms. The primary mechanism of action is through inhibition of the CYP450 14α-lanosterol demethylase enzyme, which results in altered ergosterol production and impaired cell membrane composition and permeability, which in turn leads to cation, phosphate, and low molecular weight protein leakage. In addition, miconazole inhibits fungal peroxidase and catalase while not affecting NADH oxidase activity, leading to increased production of reactive oxygen species (ROS). Increased intracellular ROS leads to downstream pleiotropic effects and eventual apoptosis. Lastly, likely as a result of lanosterol demethylation inhibition, miconazole causes a rise in intracellular levels of farnesol. This molecule participates in quorum sensing in Candida, preventing the transition from yeast to mycelial forms and thereby the formation of biofilms, which are more resistant to antibiotics. In addition, farnesol is an inhibitor of drug efflux ABC transporters, namely Candida CaCdr1p and CaCdr2p, which may additionally contribute to increased effectiveness of azole drugs. •Absorption (Drug A): Bupropion is currently available in 3 distinct, but bioequivalent formulations: immediate release (IR), sustained-release (SR), and extended-release (XL). Immediate Release Formulation In humans, following oral administration of bupropion hydrochloride tablets, peak plasma bupropion concentrations are usually achieved within 2 hours. IR formulations provide a short duration of action and are therefore generally dosed three times per day. Sustained Release Formulation In humans, following oral administration of bupropion hydrochloride sustained-release tablets (SR), peak plasma concentration (Cmax) of bupropion is usually achieved within 3 hours. SR formulations provide a 12-hour extended release of medication and are therefore generally dosed twice per day. Extended Release Formulation Following single oral administration of bupropion hydrochloride extended-release tablets (XL) to healthy volunteers, the median time to peak plasma concentrations for bupropion was approximately 5 hours. The presence of food did not affect the peak concentration or area under the curve of bupropion. XL formulations provide a 24-hour extended release of medication and are therefore generally dosed once per day/ In a trial comparing chronic dosing with bupropion hydrochloride extended-release tablets (SR) 150 mg twice daily to bupropion immediate-release formulation 100 mg 3 times daily, the steady state Cmax for bupropion after bupropion hydrochloride sustained-release tablets (SR) administration was approximately 85% of those achieved after bupropion immediate-release formulation administration. Exposure (AUC) to bupropion was equivalent for both formulations. Bioequivalence was also demonstrated for all three major active metabolites (i.e., hydroxybupropion, threohydrobupropion and erythrohydrobupropion) for both Cmax and AUC. Thus, at steady state, bupropion hydrochloride sustained-release tablets (SR) given twice daily, and the immediate-release formulation of bupropion given 3 times daily, are essentially bioequivalent for both bupropion and the 3 quantitatively important metabolites. Furthermore, in a study comparing 14-day dosing with bupropion hydrochloride extended-release tablets (XL), 300 mg once-daily to the immediate-release formulation of bupropion at 100 mg 3 times daily, equivalence was demonstrated for peak plasma concentration and area under the curve for bupropion and the three metabolites (hydroxybupropion, threohydrobupropion, and erythrohydrobupropion). Additionally, in a study comparing 14-day dosing with bupropion hydrochloride extended-release tablets (XL) 300 mg once daily to the sustained-release formulation of bupropion at 150 mg 2 times daily, equivalence was demonstrated for peak plasma concentration and area under the curve for bupropion and the three metabolites. Bupropion hydrochloride extended-release tablets (SR) can be taken with or without food. Bupropion Cmax and AUC were increased by 11% to 35% and 16% to 19%, respectively, when bupropion hydrochloride extended-release tablets (SR) was administered with food to healthy volunteers in three trials. The food effect is not considered clinically significant. Following a single-dose administration of bupropion hydrochloride extended-release tablets (SR) in humans, Cmax of bupropion's metabolite hydroxybupropion occurs approximately 6 hours post-dose and is approximately 10 times the peak level of the parent drug at steady state. The elimination half-life of hydroxybupropion is approximately 20 (±5) hours and its AUC at steady state is about 17 times that of bupropion. The times to peak concentrations for the erythrohydrobupropion and threohydrobupropion metabolites are similar to that of the hydroxybupropion metabolite. However, their elimination half-lives are longer, 33(±10) and 37 (±13) hours, respectively, and steady-state AUCs are 1.5 and 7 times that of bupropion, respectively. •Absorption (Drug B): Miconazole given to healthy volunteers as a single 50 mg oral tablet produced a mean C max of 15.1 ± 16.2 mcg/mL, a mean AUC 0-24 of 55.2 ± 35.1 mcg*h/mL, and a median T max of 7 hours (range 2.0-24.1). In these patients measurable plasma concentrations ranged from 0.5 to 0.83 mcg/mL. Topical miconazole is absorbed poorly into the systemic circulation. In pediatric patients aged 1-21 months given multiple topical applications of miconazole ointment for seven days, the plasma miconazole concentration was less than 0.5 ng/mL in 88% of the patients, with the remaining patients having a concentration of 0.57 and 0.58 ng/mL, respectively. Similarly, patients. administered with a vaginal 1200 mg ovule had a mean C max of 10.71 ng/mL, mean T max of 18.4 hours, and mean AUC 0-96 of 477.3 ng*h/mL. •Volume of distribution (Drug A): No volume of distribution available •Volume of distribution (Drug B): A 1200 mg miconazole vaginal suppository resulted in a calculated apparent volume of distribution of 95 546 L while a 100 mg vaginal cream yielded an apparent volume of distribution of 10 911L. •Protein binding (Drug A): In vitro tests show that bupropion is 84% bound to human plasma proteins at concentrations up to 200 mcg per mL. The extent of protein binding of the hydroxybupropion metabolite is similar to that for bupropion, whereas the extent of protein binding of the threohydrobupropion metabolite is about half that seen with bupropion. •Protein binding (Drug B): In vitro data suggests that miconazole binds human serum albumin, however, the clinical significance of this observation is unclear. •Metabolism (Drug A): Bupropion is extensively metabolized in humans. Three metabolites are active: hydroxybupropion, which is formed via hydroxylation of the tert-butyl group of bupropion, and the amino-alcohol isomers, threohydrobupropion and erythrohydrobupropion, which are formed via reduction of the carbonyl group. In vitro findings suggest that CYP2B6 is the principal isoenzyme involved in the formation of hydroxybupropion, while cytochrome P450 enzymes are not involved in the formation of threohydrobupropion. Hydroxybupropion has been shown to have the same affinity as bupropion for the norepinephrine transporter (NET) but approximately 50% of its antidepressant activity despite reaching concentrations of ~10-fold higher than that of the parent drug. Oxidation of the bupropion side chain results in the formation of a glycine conjugate of meta-chlorobenzoic acid, which is then excreted as the major urinary metabolite. The potency and toxicity of the metabolites relative to bupropion have not been fully characterized. However, it has been demonstrated in an antidepressant screening test in mice that hydroxybupropion is one-half as potent as bupropion, while threohydrobupropion and erythrohydrobupropion are 5-fold less potent than bupropion. This may be of clinical importance because the plasma concentrations of the metabolites are as high as or higher than those of bupropion. Bupropion and its metabolites exhibit linear kinetics following chronic administration of 300 to 450 mg per day. •Metabolism (Drug B): Miconazole is metabolized in the liver and does not give rise to any active metabolites. •Route of elimination (Drug A): Bupropion is extensively metabolized in humans. Oxidation of the bupropion side chain results in the formation of a glycine conjugate of metachlorobenzoic acid, which is then excreted as the major urinary metabolite. Following oral administration of 200 mg of 14C-bupropion in humans, 87% and 10% of the radioactive dose were recovered in the urine and feces, respectively. However, the fraction of the oral dose of bupropion excreted unchanged was only 0.5%, a finding consistent with the extensive metabolism of bupropion. •Route of elimination (Drug B): Miconazole is excreted through both urine and feces; less than 1% of unchanged miconazole is recovered in urine. •Half-life (Drug A): 24 hours •Half-life (Drug B): Miconazole has a terminal half-life of 24 hours. •Clearance (Drug A): No clearance available •Clearance (Drug B): No clearance available •Toxicity (Drug A): Symptoms of overdose include seizures, hallucinations, loss of consciousness, tachycardia, and cardiac arrest. •Toxicity (Drug B): Miconazole overdose has not been reported. Patients experiencing an overdose are at an increased risk of severe adverse effects such as headache, skin irritation, diarrhea, nausea, vomiting, abdominal pain, and dysgeusia. Symptomatic and supportive measures are recommended. Miconazole has an oral LD 50 of 500 mg/kg in rats. •Brand Names (Drug A): Aplenzin, Auvelity, Budeprion, Contrave, Forfivo, Wellbutrin, Zyban •Brand Names (Drug B): Aloe Vesta Antifungal, Baza, Critic-aid Clear, Desenex, Fungoid, Inzo, Lagicam, Lotrimin AF, Micatin, Micro-guard, Monistat, Monistat 1 Day Ovule Combination Pack, Monistat 3 Day Ovule Combination Pack, Monistat 7 Combination Pack, Oravig, Rash Relief Antifungal, Remedy Antifungal, Tetterine, Tineacide Antifungal, Ting, Vagistat, Vagistat 3 Day Combination Pack, Vusion, Zeasorb •Synonyms (Drug A): No synonyms listed •Synonyms (Drug B): Miconazol Miconazole Miconazolum •Summary (Drug A): Bupropion is a norepinephrine and dopamine reuptake inhibitor used in the treatment of major depressive disorder (MDD), seasonal affective disorder (SAD), and as an aid to smoking cessation. •Summary (Drug B): Miconazole is an azole antifungal with broad-spectrum activity used to treat fungal infections affecting the vagina, mouth and skin, including candidiasis.

Bupropion is extensively metabolized to hydroxybupropion by CYP2B6. The severity of the interaction is minor.

Question: Does Bupropion and Miconazole interact? Information: •Drug A: Bupropion •Drug B: Miconazole •Severity: MINOR •Description: The serum concentration of Bupropion can be increased when it is combined with Miconazole. •Extended Description: Bupropion is extensively metabolized to hydroxybupropion by CYP2B6. •Indication (Drug A): Bupropion is indicated for the treatment of major depressive disorder (MDD), seasonal affective disorder (SAD), and as an aid to smoking cessation. When used in combination with naltrexone as the marketed product ContraveⓇ, bupropion is indicated as an adjunct to a reduced-calorie diet and increased physical activity for chronic weight management in adults with an initial body mass index (BMI) of: 30 kg/m^2 or greater (obese) or 27 kg/m^2 or greater (overweight) in the presence of at least one weight-related comorbid condition (e.g., hypertension, type 2 diabetes mellitus, or dyslipidemia). Bupropion is also used off-label as a first-line treatment in patients with ADHD and comorbid bipolar disorder when used as an adjunct to mood stabilizers. •Indication (Drug B): Miconazole is indicated for the local treatment of oropharyngeal candidiasis in adult patients and for the adjunctive treatment of diaper dermatitis complicated by candidiasis in immunocompetent patients aged four weeks and older. Miconazole is available as both a suppository and cream for the treatment of vaginal yeast infections and the relief of associated vulvar itching and irritation. Lastly, miconazole cream is effective in treating athlete's foot (tinea pedis), jock itch (tinea cruris), ringworm infections (tinea corporis), pityriasis (formerly tinea) versicolor, and cutaneous candidiasis. •Pharmacodynamics (Drug A): Bupropion is chemically unrelated to tricyclic, tetracyclic, selective serotonin re-uptake inhibitors, or other known antidepressant agents. Compared to classical tricyclic antidepressants, Bupropion is a relatively weak inhibitor of the neuronal uptake of norepinephrine and dopamine. In addition, Bupropion does not inhibit monoamine oxidase. Bupropion has been found to be essentially inactive at the serotonin transporter (SERT)(IC50 >10 000 nM), however both bupropion and its primary metabolite hydroxybupropion have been found to block the function of cation-selective serotonin type 3A receptors (5-HT3ARs). Bupropion produces dose-related central nervous system (CNS) stimulant effects in animals, as evidenced by increased locomotor activity, increased rates of responding in various schedule-controlled operant behaviour tasks, and, at high doses, induction of mild stereotyped behaviour. Due to these stimulant effects and selective activity at dopamine and norepinephrine receptors, bupropion has been identified as having an abuse potential. Bupropion has a similar structure to the controlled substance Cathinone, and has been identified as having mild amphetamine-like activity, particularly when inhaled or injected. Bupropion is also known to lower the seizure threshold, making any pre-existing seizure conditions a contraindication to its use. This risk is exacerbated when bupropion is combined with other drugs or substances that lower the seizure threshold, such as cocaine, or in clinical situations that would increase the risk of a seizure such as abrupt alcohol or benzodiazepine withdrawal. As norepinephrine has been shown to have anticonvulsant properties, bupropion's inhibitory effects on NET are thought to contribute to its pro-convulsant activity. Bupropion has been shown to increase blood pressure and pose a risk for exacerbation of unmanaged or pre-existing hypertension, however, clinical trials of bupropion in smokers with CVD have not identified an increased incidence of CV events including stroke or heart attack. In clinical trials, the mean increase in systolic blood pressure associated with the use of bupropion was found to be 1.3 mmHg. •Pharmacodynamics (Drug B): Miconazole is an azole antifungal that functions primarily through inhibition of a specific demethylase within the CYP450 complex. As miconazole is typically applied topically and is minimally absorbed into the systemic circulation following application, the majority of patient reactions are limited to hypersensitivity and cases of anaphylaxis. Patients using intravaginal miconazole products are advised not to rely on contraceptives to prevent pregnancy and sexually transmitted infections, as well as not to use tampons concurrently. •Mechanism of action (Drug A): Bupropion is a norepinephrine/dopamine-reuptake inhibitor (NDRI) that exerts its pharmacological effects by weakly inhibiting the enzymes involved in the uptake of the neurotransmitters norepinephrine and dopamine from the synaptic cleft, therefore prolonging their duration of action within the neuronal synapse and the downstream effects of these neurotransmitters. More specifically, bupropion binds to the norepinephrine transporter (NET) and the dopamine transporter (DAT). Bupropion was originally classified as an "atypical" antidepressant because it does not exert the same effects as the classical antidepressants such as Monoamine Oxidase Inhibitors (MAOIs), Tricyclic Antidepressants (TCAs), or Selective Serotonin Reuptake Inhibitors (SSRIs). While it has comparable effectiveness to typical first-line options for the treatment of depression such as SSRIs, bupropion is a unique option for the treatment of MDD as it lacks any clinically relevant serotonergic effects, typical of other mood medications, or any effects on histamine or adrenaline receptors. Lack of activity at these receptors results in a more tolerable side effect profile; bupropion is less likely to cause sexual side effects, sedation, or weight gain as compared to SSRIs or TCAs, for example. When used as an aid to smoking cessation, bupropion is thought to confer its anti-craving and anti-withdrawal effects by inhibiting dopamine reuptake, which is thought to be involved in the reward pathways associated with nicotine, and through the antagonism of the nicotinic acetylcholinergic receptor (AChR), thereby blunting the effects of nicotine. Furthermore, the stimulatory effects produced by bupropion in the central nervous system are similar to nicotine's effects, making low doses of bupropion a suitable option as a nicotine substitute. When used in combination with naltrexone in the marketed product ContraveⓇ for chronic weight management, the two components are thought to have effects on areas of the brain involved in the regulation of food intake. This includes the hypothalamus, which is involved in appetite regulation, and the mesolimbic dopamine circuit, which is involved in reward pathways. Studies have shown that the combined activity of bupropion and naltrexone increase the firing rate of hypothalamic pro-opiomelanocortin (POMC) neurons and blockade of opioid receptor-mediated POMC auto-inhibition, which are associated with a reduction in food intake and increased energy expenditure. This combination was also found to reduce food intake when injected directly into the ventral tegmental area of the mesolimbic circuit in mice, which is an area associated with the regulation of reward pathways. •Mechanism of action (Drug B): Miconazole is an azole antifungal used to treat a variety of conditions, including those caused by Candida overgrowth. Unique among the azoles, miconazole is thought to act through three main mechanisms. The primary mechanism of action is through inhibition of the CYP450 14α-lanosterol demethylase enzyme, which results in altered ergosterol production and impaired cell membrane composition and permeability, which in turn leads to cation, phosphate, and low molecular weight protein leakage. In addition, miconazole inhibits fungal peroxidase and catalase while not affecting NADH oxidase activity, leading to increased production of reactive oxygen species (ROS). Increased intracellular ROS leads to downstream pleiotropic effects and eventual apoptosis. Lastly, likely as a result of lanosterol demethylation inhibition, miconazole causes a rise in intracellular levels of farnesol. This molecule participates in quorum sensing in Candida, preventing the transition from yeast to mycelial forms and thereby the formation of biofilms, which are more resistant to antibiotics. In addition, farnesol is an inhibitor of drug efflux ABC transporters, namely Candida CaCdr1p and CaCdr2p, which may additionally contribute to increased effectiveness of azole drugs. •Absorption (Drug A): Bupropion is currently available in 3 distinct, but bioequivalent formulations: immediate release (IR), sustained-release (SR), and extended-release (XL). Immediate Release Formulation In humans, following oral administration of bupropion hydrochloride tablets, peak plasma bupropion concentrations are usually achieved within 2 hours. IR formulations provide a short duration of action and are therefore generally dosed three times per day. Sustained Release Formulation In humans, following oral administration of bupropion hydrochloride sustained-release tablets (SR), peak plasma concentration (Cmax) of bupropion is usually achieved within 3 hours. SR formulations provide a 12-hour extended release of medication and are therefore generally dosed twice per day. Extended Release Formulation Following single oral administration of bupropion hydrochloride extended-release tablets (XL) to healthy volunteers, the median time to peak plasma concentrations for bupropion was approximately 5 hours. The presence of food did not affect the peak concentration or area under the curve of bupropion. XL formulations provide a 24-hour extended release of medication and are therefore generally dosed once per day/ In a trial comparing chronic dosing with bupropion hydrochloride extended-release tablets (SR) 150 mg twice daily to bupropion immediate-release formulation 100 mg 3 times daily, the steady state Cmax for bupropion after bupropion hydrochloride sustained-release tablets (SR) administration was approximately 85% of those achieved after bupropion immediate-release formulation administration. Exposure (AUC) to bupropion was equivalent for both formulations. Bioequivalence was also demonstrated for all three major active metabolites (i.e., hydroxybupropion, threohydrobupropion and erythrohydrobupropion) for both Cmax and AUC. Thus, at steady state, bupropion hydrochloride sustained-release tablets (SR) given twice daily, and the immediate-release formulation of bupropion given 3 times daily, are essentially bioequivalent for both bupropion and the 3 quantitatively important metabolites. Furthermore, in a study comparing 14-day dosing with bupropion hydrochloride extended-release tablets (XL), 300 mg once-daily to the immediate-release formulation of bupropion at 100 mg 3 times daily, equivalence was demonstrated for peak plasma concentration and area under the curve for bupropion and the three metabolites (hydroxybupropion, threohydrobupropion, and erythrohydrobupropion). Additionally, in a study comparing 14-day dosing with bupropion hydrochloride extended-release tablets (XL) 300 mg once daily to the sustained-release formulation of bupropion at 150 mg 2 times daily, equivalence was demonstrated for peak plasma concentration and area under the curve for bupropion and the three metabolites. Bupropion hydrochloride extended-release tablets (SR) can be taken with or without food. Bupropion Cmax and AUC were increased by 11% to 35% and 16% to 19%, respectively, when bupropion hydrochloride extended-release tablets (SR) was administered with food to healthy volunteers in three trials. The food effect is not considered clinically significant. Following a single-dose administration of bupropion hydrochloride extended-release tablets (SR) in humans, Cmax of bupropion's metabolite hydroxybupropion occurs approximately 6 hours post-dose and is approximately 10 times the peak level of the parent drug at steady state. The elimination half-life of hydroxybupropion is approximately 20 (±5) hours and its AUC at steady state is about 17 times that of bupropion. The times to peak concentrations for the erythrohydrobupropion and threohydrobupropion metabolites are similar to that of the hydroxybupropion metabolite. However, their elimination half-lives are longer, 33(±10) and 37 (±13) hours, respectively, and steady-state AUCs are 1.5 and 7 times that of bupropion, respectively. •Absorption (Drug B): Miconazole given to healthy volunteers as a single 50 mg oral tablet produced a mean C max of 15.1 ± 16.2 mcg/mL, a mean AUC 0-24 of 55.2 ± 35.1 mcg*h/mL, and a median T max of 7 hours (range 2.0-24.1). In these patients measurable plasma concentrations ranged from 0.5 to 0.83 mcg/mL. Topical miconazole is absorbed poorly into the systemic circulation. In pediatric patients aged 1-21 months given multiple topical applications of miconazole ointment for seven days, the plasma miconazole concentration was less than 0.5 ng/mL in 88% of the patients, with the remaining patients having a concentration of 0.57 and 0.58 ng/mL, respectively. Similarly, patients. administered with a vaginal 1200 mg ovule had a mean C max of 10.71 ng/mL, mean T max of 18.4 hours, and mean AUC 0-96 of 477.3 ng*h/mL. •Volume of distribution (Drug A): No volume of distribution available •Volume of distribution (Drug B): A 1200 mg miconazole vaginal suppository resulted in a calculated apparent volume of distribution of 95 546 L while a 100 mg vaginal cream yielded an apparent volume of distribution of 10 911L. •Protein binding (Drug A): In vitro tests show that bupropion is 84% bound to human plasma proteins at concentrations up to 200 mcg per mL. The extent of protein binding of the hydroxybupropion metabolite is similar to that for bupropion, whereas the extent of protein binding of the threohydrobupropion metabolite is about half that seen with bupropion. •Protein binding (Drug B): In vitro data suggests that miconazole binds human serum albumin, however, the clinical significance of this observation is unclear. •Metabolism (Drug A): Bupropion is extensively metabolized in humans. Three metabolites are active: hydroxybupropion, which is formed via hydroxylation of the tert-butyl group of bupropion, and the amino-alcohol isomers, threohydrobupropion and erythrohydrobupropion, which are formed via reduction of the carbonyl group. In vitro findings suggest that CYP2B6 is the principal isoenzyme involved in the formation of hydroxybupropion, while cytochrome P450 enzymes are not involved in the formation of threohydrobupropion. Hydroxybupropion has been shown to have the same affinity as bupropion for the norepinephrine transporter (NET) but approximately 50% of its antidepressant activity despite reaching concentrations of ~10-fold higher than that of the parent drug. Oxidation of the bupropion side chain results in the formation of a glycine conjugate of meta-chlorobenzoic acid, which is then excreted as the major urinary metabolite. The potency and toxicity of the metabolites relative to bupropion have not been fully characterized. However, it has been demonstrated in an antidepressant screening test in mice that hydroxybupropion is one-half as potent as bupropion, while threohydrobupropion and erythrohydrobupropion are 5-fold less potent than bupropion. This may be of clinical importance because the plasma concentrations of the metabolites are as high as or higher than those of bupropion. Bupropion and its metabolites exhibit linear kinetics following chronic administration of 300 to 450 mg per day. •Metabolism (Drug B): Miconazole is metabolized in the liver and does not give rise to any active metabolites. •Route of elimination (Drug A): Bupropion is extensively metabolized in humans. Oxidation of the bupropion side chain results in the formation of a glycine conjugate of metachlorobenzoic acid, which is then excreted as the major urinary metabolite. Following oral administration of 200 mg of 14C-bupropion in humans, 87% and 10% of the radioactive dose were recovered in the urine and feces, respectively. However, the fraction of the oral dose of bupropion excreted unchanged was only 0.5%, a finding consistent with the extensive metabolism of bupropion. •Route of elimination (Drug B): Miconazole is excreted through both urine and feces; less than 1% of unchanged miconazole is recovered in urine. •Half-life (Drug A): 24 hours •Half-life (Drug B): Miconazole has a terminal half-life of 24 hours. •Clearance (Drug A): No clearance available •Clearance (Drug B): No clearance available •Toxicity (Drug A): Symptoms of overdose include seizures, hallucinations, loss of consciousness, tachycardia, and cardiac arrest. •Toxicity (Drug B): Miconazole overdose has not been reported. Patients experiencing an overdose are at an increased risk of severe adverse effects such as headache, skin irritation, diarrhea, nausea, vomiting, abdominal pain, and dysgeusia. Symptomatic and supportive measures are recommended. Miconazole has an oral LD 50 of 500 mg/kg in rats. •Brand Names (Drug A): Aplenzin, Auvelity, Budeprion, Contrave, Forfivo, Wellbutrin, Zyban •Brand Names (Drug B): Aloe Vesta Antifungal, Baza, Critic-aid Clear, Desenex, Fungoid, Inzo, Lagicam, Lotrimin AF, Micatin, Micro-guard, Monistat, Monistat 1 Day Ovule Combination Pack, Monistat 3 Day Ovule Combination Pack, Monistat 7 Combination Pack, Oravig, Rash Relief Antifungal, Remedy Antifungal, Tetterine, Tineacide Antifungal, Ting, Vagistat, Vagistat 3 Day Combination Pack, Vusion, Zeasorb •Synonyms (Drug A): No synonyms listed •Synonyms (Drug B): Miconazol Miconazole Miconazolum •Summary (Drug A): Bupropion is a norepinephrine and dopamine reuptake inhibitor used in the treatment of major depressive disorder (MDD), seasonal affective disorder (SAD), and as an aid to smoking cessation. •Summary (Drug B): Miconazole is an azole antifungal with broad-spectrum activity used to treat fungal infections affecting the vagina, mouth and skin, including candidiasis. Output: Bupropion is extensively metabolized to hydroxybupropion by CYP2B6. The severity of the interaction is minor.

Does Bupropion and Midazolam interact?

•Drug A: Bupropion •Drug B: Midazolam •Severity: MODERATE •Description: The risk or severity of sedation and CNS depression can be increased when Midazolam is combined with Bupropion. •Extended Description: As a positive modulator of GABAA receptor, midazolam can have a sedative effect on the central nervous system.5 Although the exact mechanism of action of midazolam has yet to be fully outlined, it has been observed to bind allosterically to the GABA receptor at the benzodiazepine site to increase the frequency of chloride channel opening, thus increasing the GABAergic neurotransmission. Additionally, midazolam can increase the affinity of GABA to its receptor. Chloride movement can hyperpolarize neurons, causing an increase in action potential threshold and thus reducing neuron firing frequency. As a result, the overall central nervous system activity is reduced. Therefore, the concomitant use of midazolam with another central nervous system depressant can potentiate each other's depressive effect, increasing the risk of sedation. •Indication (Drug A): Bupropion is indicated for the treatment of major depressive disorder (MDD), seasonal affective disorder (SAD), and as an aid to smoking cessation. When used in combination with naltrexone as the marketed product ContraveⓇ, bupropion is indicated as an adjunct to a reduced-calorie diet and increased physical activity for chronic weight management in adults with an initial body mass index (BMI) of: 30 kg/m^2 or greater (obese) or 27 kg/m^2 or greater (overweight) in the presence of at least one weight-related comorbid condition (e.g., hypertension, type 2 diabetes mellitus, or dyslipidemia). Bupropion is also used off-label as a first-line treatment in patients with ADHD and comorbid bipolar disorder when used as an adjunct to mood stabilizers. •Indication (Drug B): Midazolam has different indications depending on its formulation by the FDA. Nasal For the nasal spray formulation, midazolam is indicated for the acute treatment of intermittent, stereotypic episodes of frequent seizure activity (i.e., seizure clusters, acute repetitive seizures) that are distinct from a patient’s usual seizure pattern in patients with epilepsy 12 years of age and older. Intravenous For the intravenous injection formulation, midazolam is indicated as an agent for sedation/anxiolysis/amnesia and prior to or during diagnostic, therapeutic or endoscopic procedures, such as bronchoscopy, gastroscopy, cystoscopy, coronary angiography, cardiac catheterization, oncology procedures, radiologic procedures, suture of lacerations and other procedures either alone or in combination with other CNS depressants. The sedative, anxiolytic and amnestic use of midazolam can also be employed pre-operatively. It can also be indicated for induction of general anesthesia, before administration of other anesthetic agents or as a component of intravenous supplementation of nitrous oxide and oxygen for a balanced anesthesia. A relatively narrower dose range of midazolam and a shorter period of induction can be achieved if midazolam is combined with narcotic premedication. Finally, midazolam can be indicated as a continous intravenous infusion for sedation of intubated and mechanically ventilated patients as a component of anesthesia or during treatment in a critical care setting. Intramuscular For the intramusuclar injection formulation, midazolam is indicated for preoperative sedation/anxiolysis/amnesia or for treatment of status epilepticus in adults. Oral Midazolam syrup is indicated for use in pediatric patients for sedation, anxiolysis and amnesia prior to diagnostic, therapeutic or endoscopic procedures or before induction of anesthesia. It is only approved in monitored settings only and not for chronic or home use. In Europe, a buccal formulation of midazolam is also approved for the treatment of prolonged, acute, convulsive seizures in infants, toddlers, children and adolescents (from 3 months to < 18 years). For infants between 3-6 months of age treatment should be in a hospital setting where monitoring is possible and resuscitation equipment is available. •Pharmacodynamics (Drug A): Bupropion is chemically unrelated to tricyclic, tetracyclic, selective serotonin re-uptake inhibitors, or other known antidepressant agents. Compared to classical tricyclic antidepressants, Bupropion is a relatively weak inhibitor of the neuronal uptake of norepinephrine and dopamine. In addition, Bupropion does not inhibit monoamine oxidase. Bupropion has been found to be essentially inactive at the serotonin transporter (SERT)(IC50 >10 000 nM), however both bupropion and its primary metabolite hydroxybupropion have been found to block the function of cation-selective serotonin type 3A receptors (5-HT3ARs). Bupropion produces dose-related central nervous system (CNS) stimulant effects in animals, as evidenced by increased locomotor activity, increased rates of responding in various schedule-controlled operant behaviour tasks, and, at high doses, induction of mild stereotyped behaviour. Due to these stimulant effects and selective activity at dopamine and norepinephrine receptors, bupropion has been identified as having an abuse potential. Bupropion has a similar structure to the controlled substance Cathinone, and has been identified as having mild amphetamine-like activity, particularly when inhaled or injected. Bupropion is also known to lower the seizure threshold, making any pre-existing seizure conditions a contraindication to its use. This risk is exacerbated when bupropion is combined with other drugs or substances that lower the seizure threshold, such as cocaine, or in clinical situations that would increase the risk of a seizure such as abrupt alcohol or benzodiazepine withdrawal. As norepinephrine has been shown to have anticonvulsant properties, bupropion's inhibitory effects on NET are thought to contribute to its pro-convulsant activity. Bupropion has been shown to increase blood pressure and pose a risk for exacerbation of unmanaged or pre-existing hypertension, however, clinical trials of bupropion in smokers with CVD have not identified an increased incidence of CV events including stroke or heart attack. In clinical trials, the mean increase in systolic blood pressure associated with the use of bupropion was found to be 1.3 mmHg. •Pharmacodynamics (Drug B): General effects Midazolam is a short-acting benzodiazepine central nervous system (CNS) depressant. Pharmacodynamic properties of midazolam and its metabolites, which are similar to those of other benzodiazepine drugs, include sedative, anxiolytic, amnestic, muscle relaxant, as well as hypnotic activities. Benzodiazepines enhance the inhibitory action of the amino acid neurotransmitter gamma-aminobutyric acid (GABA). Receptors for GABA are targeted by many important drugs that affect GABA function and are commonly used in the treatment of anxiety disorder, epilepsy, insomnia, spasticity, and aggressive behavior. Sedation and memory The onset of sedation after intramuscular administration in adults is 15 minutes, with maximal sedation occurring 30-60 minutes after injection. In one study of adults, when tested the following day, 73% of the patients who were administered midazolam intramuscularly had no recollection of memory cards shown 30 minutes following drug administration; 40% had no recollection of the memory cards shown 60 minutes after drug administration. Onset time of sedative effects in pediatric patients begins within 5 minutes and peaks at 15-30 minutes depending upon the dose administered. In the pediatric population, up to 85% had no memory of pictures shown after receiving intramuscular midazolam compared to 5% of the placebo control group. Sedation in both adult and pediatric patients is reached within 3 to 5 minutes post intravenous (IV) injection. The time of onset is affected by the dose administered and the simultaneous administration of narcotic pre-medication. Seventy-one (71%) percent of the adult patients in clinical endoscopy studies had no memory of insertion of the endoscope; 82% of the patients had no memory of withdrawal of the endoscope. Anesthesia induction When midazolam is administered intravenously (IV) for anesthetic induction, induction of anesthesia occurs in about 1.5 minutes when narcotic pre-medication has been given and in 2 to 2.5 minutes without narcotic pre-medication/ other sedative pre-medication. Impairment in a memory test was observed in 90% of the patients. •Mechanism of action (Drug A): Bupropion is a norepinephrine/dopamine-reuptake inhibitor (NDRI) that exerts its pharmacological effects by weakly inhibiting the enzymes involved in the uptake of the neurotransmitters norepinephrine and dopamine from the synaptic cleft, therefore prolonging their duration of action within the neuronal synapse and the downstream effects of these neurotransmitters. More specifically, bupropion binds to the norepinephrine transporter (NET) and the dopamine transporter (DAT). Bupropion was originally classified as an "atypical" antidepressant because it does not exert the same effects as the classical antidepressants such as Monoamine Oxidase Inhibitors (MAOIs), Tricyclic Antidepressants (TCAs), or Selective Serotonin Reuptake Inhibitors (SSRIs). While it has comparable effectiveness to typical first-line options for the treatment of depression such as SSRIs, bupropion is a unique option for the treatment of MDD as it lacks any clinically relevant serotonergic effects, typical of other mood medications, or any effects on histamine or adrenaline receptors. Lack of activity at these receptors results in a more tolerable side effect profile; bupropion is less likely to cause sexual side effects, sedation, or weight gain as compared to SSRIs or TCAs, for example. When used as an aid to smoking cessation, bupropion is thought to confer its anti-craving and anti-withdrawal effects by inhibiting dopamine reuptake, which is thought to be involved in the reward pathways associated with nicotine, and through the antagonism of the nicotinic acetylcholinergic receptor (AChR), thereby blunting the effects of nicotine. Furthermore, the stimulatory effects produced by bupropion in the central nervous system are similar to nicotine's effects, making low doses of bupropion a suitable option as a nicotine substitute. When used in combination with naltrexone in the marketed product ContraveⓇ for chronic weight management, the two components are thought to have effects on areas of the brain involved in the regulation of food intake. This includes the hypothalamus, which is involved in appetite regulation, and the mesolimbic dopamine circuit, which is involved in reward pathways. Studies have shown that the combined activity of bupropion and naltrexone increase the firing rate of hypothalamic pro-opiomelanocortin (POMC) neurons and blockade of opioid receptor-mediated POMC auto-inhibition, which are associated with a reduction in food intake and increased energy expenditure. This combination was also found to reduce food intake when injected directly into the ventral tegmental area of the mesolimbic circuit in mice, which is an area associated with the regulation of reward pathways. •Mechanism of action (Drug B): The actions of benzodiazepines such as midazolam are mediated through the inhibitory neurotransmitter gamma-aminobutyric acid (GABA), which is one of the major inhibitory neurotransmitters in the central nervous system. Benzodiazepines increase the activity of GABA, thereby producing a sedating effect, relaxing skeletal muscles, and inducing sleep, anesthesia, and amnesia. Benzodiazepines bind to the benzodiazepine site on GABA-A receptors, which potentiates the effects of GABA by increasing the frequency of chloride channel opening. These receptors have been identified in different body tissues including the heart and skeletal muscle, although mainly appear to be present in the central nervous system. •Absorption (Drug A): Bupropion is currently available in 3 distinct, but bioequivalent formulations: immediate release (IR), sustained-release (SR), and extended-release (XL). Immediate Release Formulation In humans, following oral administration of bupropion hydrochloride tablets, peak plasma bupropion concentrations are usually achieved within 2 hours. IR formulations provide a short duration of action and are therefore generally dosed three times per day. Sustained Release Formulation In humans, following oral administration of bupropion hydrochloride sustained-release tablets (SR), peak plasma concentration (Cmax) of bupropion is usually achieved within 3 hours. SR formulations provide a 12-hour extended release of medication and are therefore generally dosed twice per day. Extended Release Formulation Following single oral administration of bupropion hydrochloride extended-release tablets (XL) to healthy volunteers, the median time to peak plasma concentrations for bupropion was approximately 5 hours. The presence of food did not affect the peak concentration or area under the curve of bupropion. XL formulations provide a 24-hour extended release of medication and are therefore generally dosed once per day/ In a trial comparing chronic dosing with bupropion hydrochloride extended-release tablets (SR) 150 mg twice daily to bupropion immediate-release formulation 100 mg 3 times daily, the steady state Cmax for bupropion after bupropion hydrochloride sustained-release tablets (SR) administration was approximately 85% of those achieved after bupropion immediate-release formulation administration. Exposure (AUC) to bupropion was equivalent for both formulations. Bioequivalence was also demonstrated for all three major active metabolites (i.e., hydroxybupropion, threohydrobupropion and erythrohydrobupropion) for both Cmax and AUC. Thus, at steady state, bupropion hydrochloride sustained-release tablets (SR) given twice daily, and the immediate-release formulation of bupropion given 3 times daily, are essentially bioequivalent for both bupropion and the 3 quantitatively important metabolites. Furthermore, in a study comparing 14-day dosing with bupropion hydrochloride extended-release tablets (XL), 300 mg once-daily to the immediate-release formulation of bupropion at 100 mg 3 times daily, equivalence was demonstrated for peak plasma concentration and area under the curve for bupropion and the three metabolites (hydroxybupropion, threohydrobupropion, and erythrohydrobupropion). Additionally, in a study comparing 14-day dosing with bupropion hydrochloride extended-release tablets (XL) 300 mg once daily to the sustained-release formulation of bupropion at 150 mg 2 times daily, equivalence was demonstrated for peak plasma concentration and area under the curve for bupropion and the three metabolites. Bupropion hydrochloride extended-release tablets (SR) can be taken with or without food. Bupropion Cmax and AUC were increased by 11% to 35% and 16% to 19%, respectively, when bupropion hydrochloride extended-release tablets (SR) was administered with food to healthy volunteers in three trials. The food effect is not considered clinically significant. Following a single-dose administration of bupropion hydrochloride extended-release tablets (SR) in humans, Cmax of bupropion's metabolite hydroxybupropion occurs approximately 6 hours post-dose and is approximately 10 times the peak level of the parent drug at steady state. The elimination half-life of hydroxybupropion is approximately 20 (±5) hours and its AUC at steady state is about 17 times that of bupropion. The times to peak concentrations for the erythrohydrobupropion and threohydrobupropion metabolites are similar to that of the hydroxybupropion metabolite. However, their elimination half-lives are longer, 33(±10) and 37 (±13) hours, respectively, and steady-state AUCs are 1.5 and 7 times that of bupropion, respectively. •Absorption (Drug B): Intramuscular Following IM administration of a single 10 mg midazolam dose to healthy subjects, midazolam was absorbed with median T max (range) of 0.5 (0.25 to 0.5) hours; midazolam's mean (±SD) C max and AUC 0-∞ were 113.9 (±30.9) ng/mL and 402.7 (±97.0) ng∙h/mL, respectively. Rectal After rectal administration midazolam is absorbed rapidly. Maximum plasma concentration is reached within 30 minutes. The absolute bioavailability is approximately 50%. Intranasal Administration Following the nasal administration of a single 5 mg midazolam dose to healthy adults, midazolam was absorbed with a median T max (range) of 17.3 (7.8 to 28.2) minutes; midazolam's mean (±SD) C max and AUC 0-∞ were 54.7 (±30.4) ng/mL and 126.2 (±59) ng∙h/mL, respectively. The mean absolute bioavailability is approximately 44%. Oral In pediatric patients from 6 months to <16 years old, the mean T max values across dose groups (0.25, 0.5, and 1.0 mg/kg) range from 0.17 to 2.65 hours. Midazolam also exhibits linear pharmacokinetics within this dose range (up to a maximum dose of 40 mg). Linearity was also demonstrated across the doses within the age group of 2 years to <12 years having 18 patients at each of the three doses. Due to first-pass metabolism, only 40-50% of the administered oral dose reaches the circulation. The absolute bioavailability of midazolam is about 36%, which is not affected by pediatric age or weight. C max and AUC 0-∞ were also calculated to range from 28 to 201 ng/mL and 67.6 to 821 ng∙h/mL respectively. Buccal After oromucosal administration midazolam is absorbed rapidly. Maximum plasma concentration is reached within 30 minutes in children. The absolute bioavailability of oromucosal midazolam is about 75% in adults. The bioavailability of oromucosal midazolam has been estimated at 87% in children with severe malaria and convulsions. C max and AUC 0-∞ were also calculated to range from 87 to 148 ng/mL and 168 to 254 ng∙h/mL respectively. •Volume of distribution (Drug A): No volume of distribution available •Volume of distribution (Drug B): Female gender, old age, and obesity may increase the volume of distribution. Midazolam may also cross the placenta and has been detected in human milk and cerebrospinal fluid. Intravenous administration In pediatric patients (6 months to <16 years) receiving 0.15 mg/kg IV midazolam, the mean steady-state volume of distribution ranged from 1.24 to 2.02 L/kg. For healthy adult patients, the volume of distribution determined from six single-dose pharmacokinetic studies ranged from 1.0 to 3.1 L/kg. Intramuscular administration The mean (±SD) apparent volume of distribution (Vz/F) of midazolam following a single IM dose of 10 mg midazolam was 2117 (±845.1) mL/kg in healthy subjects. Intranasal The estimated total volume of distribution of midazolam is 226.5 L. Buccal The steady-state volume of distribution following oromucosal administration is estimated to be 5.3 l/kg. •Protein binding (Drug A): In vitro tests show that bupropion is 84% bound to human plasma proteins at concentrations up to 200 mcg per mL. The extent of protein binding of the hydroxybupropion metabolite is similar to that for bupropion, whereas the extent of protein binding of the threohydrobupropion metabolite is about half that seen with bupropion. •Protein binding (Drug B): In adults and pediatric patients, midazolam is approximately 97% bound to plasma protein, principally albumin. In healthy volunteers, 1-hydroxy midazolam is bound to the extent of 89%. •Metabolism (Drug A): Bupropion is extensively metabolized in humans. Three metabolites are active: hydroxybupropion, which is formed via hydroxylation of the tert-butyl group of bupropion, and the amino-alcohol isomers, threohydrobupropion and erythrohydrobupropion, which are formed via reduction of the carbonyl group. In vitro findings suggest that CYP2B6 is the principal isoenzyme involved in the formation of hydroxybupropion, while cytochrome P450 enzymes are not involved in the formation of threohydrobupropion. Hydroxybupropion has been shown to have the same affinity as bupropion for the norepinephrine transporter (NET) but approximately 50% of its antidepressant activity despite reaching concentrations of ~10-fold higher than that of the parent drug. Oxidation of the bupropion side chain results in the formation of a glycine conjugate of meta-chlorobenzoic acid, which is then excreted as the major urinary metabolite. The potency and toxicity of the metabolites relative to bupropion have not been fully characterized. However, it has been demonstrated in an antidepressant screening test in mice that hydroxybupropion is one-half as potent as bupropion, while threohydrobupropion and erythrohydrobupropion are 5-fold less potent than bupropion. This may be of clinical importance because the plasma concentrations of the metabolites are as high as or higher than those of bupropion. Bupropion and its metabolites exhibit linear kinetics following chronic administration of 300 to 450 mg per day. •Metabolism (Drug B): In vitro studies with human liver microsomes indicate that the biotransformation of midazolam is mediated by the cytochrome P450-3A4 (CYP3A4). This enzyme is present in gastrointestinal tract mucosa, as well as in the liver. The 1-hydroxy-midazolam (also termed alpha-hydroxymidazolam) metabolite comprises 60% to 70% of the biotransformation products of midazolam, while 4-hydroxy-midazolam constitutes 5% or less. Small amounts of a dihydroxy derivative have also been detected, but not quantified. Midazolam also undergoes N-glucuronidation via UGT1A4 after the process of hepatic oxidation by cytochrome enzymes. Studies of the intravenous administration of 1-hydroxy-midazolam in humans suggest that 1-hydroxymidazolam is at least as potent as the parent compound, and may contribute to the net pharmacologic activity of midazolam. In vitro studies have demonstrated that the affinities of 1- and 4-hydroxy-midazolam for the benzodiazepine receptor are approximately 20% and 7%, respectively, relative to midazolam. •Route of elimination (Drug A): Bupropion is extensively metabolized in humans. Oxidation of the bupropion side chain results in the formation of a glycine conjugate of metachlorobenzoic acid, which is then excreted as the major urinary metabolite. Following oral administration of 200 mg of 14C-bupropion in humans, 87% and 10% of the radioactive dose were recovered in the urine and feces, respectively. However, the fraction of the oral dose of bupropion excreted unchanged was only 0.5%, a finding consistent with the extensive metabolism of bupropion. •Route of elimination (Drug B): The α-hydroxymidazolam glucuronide conjugate of midazolam is excreted in the urine. No significant amount of parent drug or metabolites is found in urine before beta-glucuronidase and sulfatase deconjugation, suggesting that the urinary metabolites are excreted mainly as conjugates. The amount of midazolam excreted unchanged in the urine when given intravenously is less than 0.5%. 45% to 57% of the dose was excreted in the urine as 1-hydroxymethyl midazolam conjugate. The principal urinary excretion products are glucuronide conjugates of hydroxylated derivatives. Plasma clearance of midazolam is higher in patients that remain in the supine position, because of a 40-60 percent increase in hepatic blood flow during supination. Pregnancy may also increase the metabolism of midazolam. •Half-life (Drug A): 24 hours •Half-life (Drug B): Intravenous: Six single-dose pharmacokinetic studies involving healthy adults yield an elimination half-life of 1.8 to 6.4 hours (mean of approximately 3 hours). Intramuscular Following IM administration of 10 mg midazolam, the mean (±SD) elimination half-life of midazolam was 4.2 (±1.87) hours. Intranasal Following the administration of NAYZILAM in clinical trials, median midazolam and 1-hydroxy-midazolam elimination half-lives ranged from 2.1 to 6.2 hours and 2.7 to 7.2 hours, respectively, independent of dose. Oral The mean elimination half-life of midazolam ranged from 2.2 to 6.8 hours following single oral doses of 0.25, 0.5, and 1.0 mg/kg of midazolam HCl syrup. * Buccal The initial and terminal elimination half-lives are 27 and 204 minutes, respectively. •Clearance (Drug A): No clearance available •Clearance (Drug B): Intramuscular Following IM administration of 10 mg midazolam, the apparent total body clearance (CL/F) of midazolam was 367.3 (±73.5) mL/hr/kg. Intravenous: Six single-dose pharmacokinetic studies involving healthy adults yield a total clearance (Cl) of 0.25 to 0.54 L/hr/kg. Intranasal Midazolam clearance was calculated to be 1.9 mL/min/kg Oral Following a group of patients receiving the 0.15 mg/kg IV dose, the mean total clearance ranged from 9.3 to 11.0 mL/min/kg. * Buccal Plasma clearance of midazolam in children following oromucosal administration is 30 ml/kg/min. •Toxicity (Drug A): Symptoms of overdose include seizures, hallucinations, loss of consciousness, tachycardia, and cardiac arrest. •Toxicity (Drug B): LD 50 =215 mg/kg, in rats. Overdose Signs of overdose include sedation, somnolence, confusion, impaired coordination, diminished reflexes, coma, and deleterious effects on vital signs. Serious cardiorespiratory adverse reactions have occurred, sometimes ending in death or permanent neurologic effects, after the administration of midazolam. A note on cardiac and respiratory depression After administration of midazolam, continuous monitoring of respiratory and cardiac function is recommended until the patient is in stable condition. Serious and life-threatening cardiorespiratory adverse reactions, including hypoventilation, airway obstruction, apnea, and hypotension have been reported with the use of midazolam. Patients should be monitored in a setting with immediate access to resuscitative drugs if they are required. Resuscitation equipment and personnel trained in their use and skilled in airway management should be available when midazolam is administered. The usual recommended intramuscular pre-medicating doses of midazolam do not depress the ventilatory response to carbon dioxide stimulation to a clinically significant extent in adults. Intravenous induction doses of midazolam depress the ventilatory response to carbon dioxide stimulation for at least 15 minutes longer than the duration of ventilatory depression following administration of thiopental in adults. Impairment of ventilatory response to carbon dioxide is more severe in adult patients diagnosed with chronic obstructive pulmonary disease (COPD). A note on dependence When midazolam is used in long-term sedation in the ICU (intensive care unit) or other settings, physical dependence on midazolam may develop. The risk of dependence increases with dose and duration of treatment; this risk is also greater in patients with a medical history of substance abuse. Special caution should be exercised when administering midazolam in the following populations High-risk patients include adults over 60 years of age, chronically ill or debilitated patients, which may include patients with chronic respiratory insufficiency, patients with chronic renal failure, impaired hepatic function or with impaired cardiac function, pediatric patients (especially those with cardiovascular instability). These high-risk patients require lower dosages and should be monitored on a continuous basis for early signs of alterations of vital functions, so that appropriate management may be administered. Mutagenesis Midazolam was negative for genotoxicity during in vitro and in vivo assays. Impairment of Fertility When midazolam (0, 1, 4, or 16 mg/kg) was given orally to male and female rats before and during mating and continuing in females throughout gestation and lactation, no adverse effects on male or female fertility were observed. Midazolam plasma exposures (AUC) at the highest dose tested were approximately 6 times that in humans at the recomended human dose. •Brand Names (Drug A): Aplenzin, Auvelity, Budeprion, Contrave, Forfivo, Wellbutrin, Zyban •Brand Names (Drug B): Buccolam, Busulfex, Nayzilam, Seizalam •Synonyms (Drug A): No synonyms listed •Synonyms (Drug B): No synonyms listed •Summary (Drug A): Bupropion is a norepinephrine and dopamine reuptake inhibitor used in the treatment of major depressive disorder (MDD), seasonal affective disorder (SAD), and as an aid to smoking cessation. •Summary (Drug B): Midazolam is a short-acting benzodiazepine with rapid onset that is commonly used in seizures, anesthesia and anxiety disorders.

As a positive modulator of GABAA receptor, midazolam can have a sedative effect on the central nervous system.5 Although the exact mechanism of action of midazolam has yet to be fully outlined, it has been observed to bind allosterically to the GABA receptor at the benzodiazepine site to increase the frequency of chloride channel opening, thus increasing the GABAergic neurotransmission. Additionally, midazolam can increase the affinity of GABA to its receptor. Chloride movement can hyperpolarize neurons, causing an increase in action potential threshold and thus reducing neuron firing frequency. As a result, the overall central nervous system activity is reduced. Therefore, the concomitant use of midazolam with another central nervous system depressant can potentiate each other's depressive effect, increasing the risk of sedation. The severity of the interaction is moderate.

Question: Does Bupropion and Midazolam interact? Information: •Drug A: Bupropion •Drug B: Midazolam •Severity: MODERATE •Description: The risk or severity of sedation and CNS depression can be increased when Midazolam is combined with Bupropion. •Extended Description: As a positive modulator of GABAA receptor, midazolam can have a sedative effect on the central nervous system.5 Although the exact mechanism of action of midazolam has yet to be fully outlined, it has been observed to bind allosterically to the GABA receptor at the benzodiazepine site to increase the frequency of chloride channel opening, thus increasing the GABAergic neurotransmission. Additionally, midazolam can increase the affinity of GABA to its receptor. Chloride movement can hyperpolarize neurons, causing an increase in action potential threshold and thus reducing neuron firing frequency. As a result, the overall central nervous system activity is reduced. Therefore, the concomitant use of midazolam with another central nervous system depressant can potentiate each other's depressive effect, increasing the risk of sedation. •Indication (Drug A): Bupropion is indicated for the treatment of major depressive disorder (MDD), seasonal affective disorder (SAD), and as an aid to smoking cessation. When used in combination with naltrexone as the marketed product ContraveⓇ, bupropion is indicated as an adjunct to a reduced-calorie diet and increased physical activity for chronic weight management in adults with an initial body mass index (BMI) of: 30 kg/m^2 or greater (obese) or 27 kg/m^2 or greater (overweight) in the presence of at least one weight-related comorbid condition (e.g., hypertension, type 2 diabetes mellitus, or dyslipidemia). Bupropion is also used off-label as a first-line treatment in patients with ADHD and comorbid bipolar disorder when used as an adjunct to mood stabilizers. •Indication (Drug B): Midazolam has different indications depending on its formulation by the FDA. Nasal For the nasal spray formulation, midazolam is indicated for the acute treatment of intermittent, stereotypic episodes of frequent seizure activity (i.e., seizure clusters, acute repetitive seizures) that are distinct from a patient’s usual seizure pattern in patients with epilepsy 12 years of age and older. Intravenous For the intravenous injection formulation, midazolam is indicated as an agent for sedation/anxiolysis/amnesia and prior to or during diagnostic, therapeutic or endoscopic procedures, such as bronchoscopy, gastroscopy, cystoscopy, coronary angiography, cardiac catheterization, oncology procedures, radiologic procedures, suture of lacerations and other procedures either alone or in combination with other CNS depressants. The sedative, anxiolytic and amnestic use of midazolam can also be employed pre-operatively. It can also be indicated for induction of general anesthesia, before administration of other anesthetic agents or as a component of intravenous supplementation of nitrous oxide and oxygen for a balanced anesthesia. A relatively narrower dose range of midazolam and a shorter period of induction can be achieved if midazolam is combined with narcotic premedication. Finally, midazolam can be indicated as a continous intravenous infusion for sedation of intubated and mechanically ventilated patients as a component of anesthesia or during treatment in a critical care setting. Intramuscular For the intramusuclar injection formulation, midazolam is indicated for preoperative sedation/anxiolysis/amnesia or for treatment of status epilepticus in adults. Oral Midazolam syrup is indicated for use in pediatric patients for sedation, anxiolysis and amnesia prior to diagnostic, therapeutic or endoscopic procedures or before induction of anesthesia. It is only approved in monitored settings only and not for chronic or home use. In Europe, a buccal formulation of midazolam is also approved for the treatment of prolonged, acute, convulsive seizures in infants, toddlers, children and adolescents (from 3 months to < 18 years). For infants between 3-6 months of age treatment should be in a hospital setting where monitoring is possible and resuscitation equipment is available. •Pharmacodynamics (Drug A): Bupropion is chemically unrelated to tricyclic, tetracyclic, selective serotonin re-uptake inhibitors, or other known antidepressant agents. Compared to classical tricyclic antidepressants, Bupropion is a relatively weak inhibitor of the neuronal uptake of norepinephrine and dopamine. In addition, Bupropion does not inhibit monoamine oxidase. Bupropion has been found to be essentially inactive at the serotonin transporter (SERT)(IC50 >10 000 nM), however both bupropion and its primary metabolite hydroxybupropion have been found to block the function of cation-selective serotonin type 3A receptors (5-HT3ARs). Bupropion produces dose-related central nervous system (CNS) stimulant effects in animals, as evidenced by increased locomotor activity, increased rates of responding in various schedule-controlled operant behaviour tasks, and, at high doses, induction of mild stereotyped behaviour. Due to these stimulant effects and selective activity at dopamine and norepinephrine receptors, bupropion has been identified as having an abuse potential. Bupropion has a similar structure to the controlled substance Cathinone, and has been identified as having mild amphetamine-like activity, particularly when inhaled or injected. Bupropion is also known to lower the seizure threshold, making any pre-existing seizure conditions a contraindication to its use. This risk is exacerbated when bupropion is combined with other drugs or substances that lower the seizure threshold, such as cocaine, or in clinical situations that would increase the risk of a seizure such as abrupt alcohol or benzodiazepine withdrawal. As norepinephrine has been shown to have anticonvulsant properties, bupropion's inhibitory effects on NET are thought to contribute to its pro-convulsant activity. Bupropion has been shown to increase blood pressure and pose a risk for exacerbation of unmanaged or pre-existing hypertension, however, clinical trials of bupropion in smokers with CVD have not identified an increased incidence of CV events including stroke or heart attack. In clinical trials, the mean increase in systolic blood pressure associated with the use of bupropion was found to be 1.3 mmHg. •Pharmacodynamics (Drug B): General effects Midazolam is a short-acting benzodiazepine central nervous system (CNS) depressant. Pharmacodynamic properties of midazolam and its metabolites, which are similar to those of other benzodiazepine drugs, include sedative, anxiolytic, amnestic, muscle relaxant, as well as hypnotic activities. Benzodiazepines enhance the inhibitory action of the amino acid neurotransmitter gamma-aminobutyric acid (GABA). Receptors for GABA are targeted by many important drugs that affect GABA function and are commonly used in the treatment of anxiety disorder, epilepsy, insomnia, spasticity, and aggressive behavior. Sedation and memory The onset of sedation after intramuscular administration in adults is 15 minutes, with maximal sedation occurring 30-60 minutes after injection. In one study of adults, when tested the following day, 73% of the patients who were administered midazolam intramuscularly had no recollection of memory cards shown 30 minutes following drug administration; 40% had no recollection of the memory cards shown 60 minutes after drug administration. Onset time of sedative effects in pediatric patients begins within 5 minutes and peaks at 15-30 minutes depending upon the dose administered. In the pediatric population, up to 85% had no memory of pictures shown after receiving intramuscular midazolam compared to 5% of the placebo control group. Sedation in both adult and pediatric patients is reached within 3 to 5 minutes post intravenous (IV) injection. The time of onset is affected by the dose administered and the simultaneous administration of narcotic pre-medication. Seventy-one (71%) percent of the adult patients in clinical endoscopy studies had no memory of insertion of the endoscope; 82% of the patients had no memory of withdrawal of the endoscope. Anesthesia induction When midazolam is administered intravenously (IV) for anesthetic induction, induction of anesthesia occurs in about 1.5 minutes when narcotic pre-medication has been given and in 2 to 2.5 minutes without narcotic pre-medication/ other sedative pre-medication. Impairment in a memory test was observed in 90% of the patients. •Mechanism of action (Drug A): Bupropion is a norepinephrine/dopamine-reuptake inhibitor (NDRI) that exerts its pharmacological effects by weakly inhibiting the enzymes involved in the uptake of the neurotransmitters norepinephrine and dopamine from the synaptic cleft, therefore prolonging their duration of action within the neuronal synapse and the downstream effects of these neurotransmitters. More specifically, bupropion binds to the norepinephrine transporter (NET) and the dopamine transporter (DAT). Bupropion was originally classified as an "atypical" antidepressant because it does not exert the same effects as the classical antidepressants such as Monoamine Oxidase Inhibitors (MAOIs), Tricyclic Antidepressants (TCAs), or Selective Serotonin Reuptake Inhibitors (SSRIs). While it has comparable effectiveness to typical first-line options for the treatment of depression such as SSRIs, bupropion is a unique option for the treatment of MDD as it lacks any clinically relevant serotonergic effects, typical of other mood medications, or any effects on histamine or adrenaline receptors. Lack of activity at these receptors results in a more tolerable side effect profile; bupropion is less likely to cause sexual side effects, sedation, or weight gain as compared to SSRIs or TCAs, for example. When used as an aid to smoking cessation, bupropion is thought to confer its anti-craving and anti-withdrawal effects by inhibiting dopamine reuptake, which is thought to be involved in the reward pathways associated with nicotine, and through the antagonism of the nicotinic acetylcholinergic receptor (AChR), thereby blunting the effects of nicotine. Furthermore, the stimulatory effects produced by bupropion in the central nervous system are similar to nicotine's effects, making low doses of bupropion a suitable option as a nicotine substitute. When used in combination with naltrexone in the marketed product ContraveⓇ for chronic weight management, the two components are thought to have effects on areas of the brain involved in the regulation of food intake. This includes the hypothalamus, which is involved in appetite regulation, and the mesolimbic dopamine circuit, which is involved in reward pathways. Studies have shown that the combined activity of bupropion and naltrexone increase the firing rate of hypothalamic pro-opiomelanocortin (POMC) neurons and blockade of opioid receptor-mediated POMC auto-inhibition, which are associated with a reduction in food intake and increased energy expenditure. This combination was also found to reduce food intake when injected directly into the ventral tegmental area of the mesolimbic circuit in mice, which is an area associated with the regulation of reward pathways. •Mechanism of action (Drug B): The actions of benzodiazepines such as midazolam are mediated through the inhibitory neurotransmitter gamma-aminobutyric acid (GABA), which is one of the major inhibitory neurotransmitters in the central nervous system. Benzodiazepines increase the activity of GABA, thereby producing a sedating effect, relaxing skeletal muscles, and inducing sleep, anesthesia, and amnesia. Benzodiazepines bind to the benzodiazepine site on GABA-A receptors, which potentiates the effects of GABA by increasing the frequency of chloride channel opening. These receptors have been identified in different body tissues including the heart and skeletal muscle, although mainly appear to be present in the central nervous system. •Absorption (Drug A): Bupropion is currently available in 3 distinct, but bioequivalent formulations: immediate release (IR), sustained-release (SR), and extended-release (XL). Immediate Release Formulation In humans, following oral administration of bupropion hydrochloride tablets, peak plasma bupropion concentrations are usually achieved within 2 hours. IR formulations provide a short duration of action and are therefore generally dosed three times per day. Sustained Release Formulation In humans, following oral administration of bupropion hydrochloride sustained-release tablets (SR), peak plasma concentration (Cmax) of bupropion is usually achieved within 3 hours. SR formulations provide a 12-hour extended release of medication and are therefore generally dosed twice per day. Extended Release Formulation Following single oral administration of bupropion hydrochloride extended-release tablets (XL) to healthy volunteers, the median time to peak plasma concentrations for bupropion was approximately 5 hours. The presence of food did not affect the peak concentration or area under the curve of bupropion. XL formulations provide a 24-hour extended release of medication and are therefore generally dosed once per day/ In a trial comparing chronic dosing with bupropion hydrochloride extended-release tablets (SR) 150 mg twice daily to bupropion immediate-release formulation 100 mg 3 times daily, the steady state Cmax for bupropion after bupropion hydrochloride sustained-release tablets (SR) administration was approximately 85% of those achieved after bupropion immediate-release formulation administration. Exposure (AUC) to bupropion was equivalent for both formulations. Bioequivalence was also demonstrated for all three major active metabolites (i.e., hydroxybupropion, threohydrobupropion and erythrohydrobupropion) for both Cmax and AUC. Thus, at steady state, bupropion hydrochloride sustained-release tablets (SR) given twice daily, and the immediate-release formulation of bupropion given 3 times daily, are essentially bioequivalent for both bupropion and the 3 quantitatively important metabolites. Furthermore, in a study comparing 14-day dosing with bupropion hydrochloride extended-release tablets (XL), 300 mg once-daily to the immediate-release formulation of bupropion at 100 mg 3 times daily, equivalence was demonstrated for peak plasma concentration and area under the curve for bupropion and the three metabolites (hydroxybupropion, threohydrobupropion, and erythrohydrobupropion). Additionally, in a study comparing 14-day dosing with bupropion hydrochloride extended-release tablets (XL) 300 mg once daily to the sustained-release formulation of bupropion at 150 mg 2 times daily, equivalence was demonstrated for peak plasma concentration and area under the curve for bupropion and the three metabolites. Bupropion hydrochloride extended-release tablets (SR) can be taken with or without food. Bupropion Cmax and AUC were increased by 11% to 35% and 16% to 19%, respectively, when bupropion hydrochloride extended-release tablets (SR) was administered with food to healthy volunteers in three trials. The food effect is not considered clinically significant. Following a single-dose administration of bupropion hydrochloride extended-release tablets (SR) in humans, Cmax of bupropion's metabolite hydroxybupropion occurs approximately 6 hours post-dose and is approximately 10 times the peak level of the parent drug at steady state. The elimination half-life of hydroxybupropion is approximately 20 (±5) hours and its AUC at steady state is about 17 times that of bupropion. The times to peak concentrations for the erythrohydrobupropion and threohydrobupropion metabolites are similar to that of the hydroxybupropion metabolite. However, their elimination half-lives are longer, 33(±10) and 37 (±13) hours, respectively, and steady-state AUCs are 1.5 and 7 times that of bupropion, respectively. •Absorption (Drug B): Intramuscular Following IM administration of a single 10 mg midazolam dose to healthy subjects, midazolam was absorbed with median T max (range) of 0.5 (0.25 to 0.5) hours; midazolam's mean (±SD) C max and AUC 0-∞ were 113.9 (±30.9) ng/mL and 402.7 (±97.0) ng∙h/mL, respectively. Rectal After rectal administration midazolam is absorbed rapidly. Maximum plasma concentration is reached within 30 minutes. The absolute bioavailability is approximately 50%. Intranasal Administration Following the nasal administration of a single 5 mg midazolam dose to healthy adults, midazolam was absorbed with a median T max (range) of 17.3 (7.8 to 28.2) minutes; midazolam's mean (±SD) C max and AUC 0-∞ were 54.7 (±30.4) ng/mL and 126.2 (±59) ng∙h/mL, respectively. The mean absolute bioavailability is approximately 44%. Oral In pediatric patients from 6 months to <16 years old, the mean T max values across dose groups (0.25, 0.5, and 1.0 mg/kg) range from 0.17 to 2.65 hours. Midazolam also exhibits linear pharmacokinetics within this dose range (up to a maximum dose of 40 mg). Linearity was also demonstrated across the doses within the age group of 2 years to <12 years having 18 patients at each of the three doses. Due to first-pass metabolism, only 40-50% of the administered oral dose reaches the circulation. The absolute bioavailability of midazolam is about 36%, which is not affected by pediatric age or weight. C max and AUC 0-∞ were also calculated to range from 28 to 201 ng/mL and 67.6 to 821 ng∙h/mL respectively. Buccal After oromucosal administration midazolam is absorbed rapidly. Maximum plasma concentration is reached within 30 minutes in children. The absolute bioavailability of oromucosal midazolam is about 75% in adults. The bioavailability of oromucosal midazolam has been estimated at 87% in children with severe malaria and convulsions. C max and AUC 0-∞ were also calculated to range from 87 to 148 ng/mL and 168 to 254 ng∙h/mL respectively. •Volume of distribution (Drug A): No volume of distribution available •Volume of distribution (Drug B): Female gender, old age, and obesity may increase the volume of distribution. Midazolam may also cross the placenta and has been detected in human milk and cerebrospinal fluid. Intravenous administration In pediatric patients (6 months to <16 years) receiving 0.15 mg/kg IV midazolam, the mean steady-state volume of distribution ranged from 1.24 to 2.02 L/kg. For healthy adult patients, the volume of distribution determined from six single-dose pharmacokinetic studies ranged from 1.0 to 3.1 L/kg. Intramuscular administration The mean (±SD) apparent volume of distribution (Vz/F) of midazolam following a single IM dose of 10 mg midazolam was 2117 (±845.1) mL/kg in healthy subjects. Intranasal The estimated total volume of distribution of midazolam is 226.5 L. Buccal The steady-state volume of distribution following oromucosal administration is estimated to be 5.3 l/kg. •Protein binding (Drug A): In vitro tests show that bupropion is 84% bound to human plasma proteins at concentrations up to 200 mcg per mL. The extent of protein binding of the hydroxybupropion metabolite is similar to that for bupropion, whereas the extent of protein binding of the threohydrobupropion metabolite is about half that seen with bupropion. •Protein binding (Drug B): In adults and pediatric patients, midazolam is approximately 97% bound to plasma protein, principally albumin. In healthy volunteers, 1-hydroxy midazolam is bound to the extent of 89%. •Metabolism (Drug A): Bupropion is extensively metabolized in humans. Three metabolites are active: hydroxybupropion, which is formed via hydroxylation of the tert-butyl group of bupropion, and the amino-alcohol isomers, threohydrobupropion and erythrohydrobupropion, which are formed via reduction of the carbonyl group. In vitro findings suggest that CYP2B6 is the principal isoenzyme involved in the formation of hydroxybupropion, while cytochrome P450 enzymes are not involved in the formation of threohydrobupropion. Hydroxybupropion has been shown to have the same affinity as bupropion for the norepinephrine transporter (NET) but approximately 50% of its antidepressant activity despite reaching concentrations of ~10-fold higher than that of the parent drug. Oxidation of the bupropion side chain results in the formation of a glycine conjugate of meta-chlorobenzoic acid, which is then excreted as the major urinary metabolite. The potency and toxicity of the metabolites relative to bupropion have not been fully characterized. However, it has been demonstrated in an antidepressant screening test in mice that hydroxybupropion is one-half as potent as bupropion, while threohydrobupropion and erythrohydrobupropion are 5-fold less potent than bupropion. This may be of clinical importance because the plasma concentrations of the metabolites are as high as or higher than those of bupropion. Bupropion and its metabolites exhibit linear kinetics following chronic administration of 300 to 450 mg per day. •Metabolism (Drug B): In vitro studies with human liver microsomes indicate that the biotransformation of midazolam is mediated by the cytochrome P450-3A4 (CYP3A4). This enzyme is present in gastrointestinal tract mucosa, as well as in the liver. The 1-hydroxy-midazolam (also termed alpha-hydroxymidazolam) metabolite comprises 60% to 70% of the biotransformation products of midazolam, while 4-hydroxy-midazolam constitutes 5% or less. Small amounts of a dihydroxy derivative have also been detected, but not quantified. Midazolam also undergoes N-glucuronidation via UGT1A4 after the process of hepatic oxidation by cytochrome enzymes. Studies of the intravenous administration of 1-hydroxy-midazolam in humans suggest that 1-hydroxymidazolam is at least as potent as the parent compound, and may contribute to the net pharmacologic activity of midazolam. In vitro studies have demonstrated that the affinities of 1- and 4-hydroxy-midazolam for the benzodiazepine receptor are approximately 20% and 7%, respectively, relative to midazolam. •Route of elimination (Drug A): Bupropion is extensively metabolized in humans. Oxidation of the bupropion side chain results in the formation of a glycine conjugate of metachlorobenzoic acid, which is then excreted as the major urinary metabolite. Following oral administration of 200 mg of 14C-bupropion in humans, 87% and 10% of the radioactive dose were recovered in the urine and feces, respectively. However, the fraction of the oral dose of bupropion excreted unchanged was only 0.5%, a finding consistent with the extensive metabolism of bupropion. •Route of elimination (Drug B): The α-hydroxymidazolam glucuronide conjugate of midazolam is excreted in the urine. No significant amount of parent drug or metabolites is found in urine before beta-glucuronidase and sulfatase deconjugation, suggesting that the urinary metabolites are excreted mainly as conjugates. The amount of midazolam excreted unchanged in the urine when given intravenously is less than 0.5%. 45% to 57% of the dose was excreted in the urine as 1-hydroxymethyl midazolam conjugate. The principal urinary excretion products are glucuronide conjugates of hydroxylated derivatives. Plasma clearance of midazolam is higher in patients that remain in the supine position, because of a 40-60 percent increase in hepatic blood flow during supination. Pregnancy may also increase the metabolism of midazolam. •Half-life (Drug A): 24 hours •Half-life (Drug B): Intravenous: Six single-dose pharmacokinetic studies involving healthy adults yield an elimination half-life of 1.8 to 6.4 hours (mean of approximately 3 hours). Intramuscular Following IM administration of 10 mg midazolam, the mean (±SD) elimination half-life of midazolam was 4.2 (±1.87) hours. Intranasal Following the administration of NAYZILAM in clinical trials, median midazolam and 1-hydroxy-midazolam elimination half-lives ranged from 2.1 to 6.2 hours and 2.7 to 7.2 hours, respectively, independent of dose. Oral The mean elimination half-life of midazolam ranged from 2.2 to 6.8 hours following single oral doses of 0.25, 0.5, and 1.0 mg/kg of midazolam HCl syrup. * Buccal The initial and terminal elimination half-lives are 27 and 204 minutes, respectively. •Clearance (Drug A): No clearance available •Clearance (Drug B): Intramuscular Following IM administration of 10 mg midazolam, the apparent total body clearance (CL/F) of midazolam was 367.3 (±73.5) mL/hr/kg. Intravenous: Six single-dose pharmacokinetic studies involving healthy adults yield a total clearance (Cl) of 0.25 to 0.54 L/hr/kg. Intranasal Midazolam clearance was calculated to be 1.9 mL/min/kg Oral Following a group of patients receiving the 0.15 mg/kg IV dose, the mean total clearance ranged from 9.3 to 11.0 mL/min/kg. * Buccal Plasma clearance of midazolam in children following oromucosal administration is 30 ml/kg/min. •Toxicity (Drug A): Symptoms of overdose include seizures, hallucinations, loss of consciousness, tachycardia, and cardiac arrest. •Toxicity (Drug B): LD 50 =215 mg/kg, in rats. Overdose Signs of overdose include sedation, somnolence, confusion, impaired coordination, diminished reflexes, coma, and deleterious effects on vital signs. Serious cardiorespiratory adverse reactions have occurred, sometimes ending in death or permanent neurologic effects, after the administration of midazolam. A note on cardiac and respiratory depression After administration of midazolam, continuous monitoring of respiratory and cardiac function is recommended until the patient is in stable condition. Serious and life-threatening cardiorespiratory adverse reactions, including hypoventilation, airway obstruction, apnea, and hypotension have been reported with the use of midazolam. Patients should be monitored in a setting with immediate access to resuscitative drugs if they are required. Resuscitation equipment and personnel trained in their use and skilled in airway management should be available when midazolam is administered. The usual recommended intramuscular pre-medicating doses of midazolam do not depress the ventilatory response to carbon dioxide stimulation to a clinically significant extent in adults. Intravenous induction doses of midazolam depress the ventilatory response to carbon dioxide stimulation for at least 15 minutes longer than the duration of ventilatory depression following administration of thiopental in adults. Impairment of ventilatory response to carbon dioxide is more severe in adult patients diagnosed with chronic obstructive pulmonary disease (COPD). A note on dependence When midazolam is used in long-term sedation in the ICU (intensive care unit) or other settings, physical dependence on midazolam may develop. The risk of dependence increases with dose and duration of treatment; this risk is also greater in patients with a medical history of substance abuse. Special caution should be exercised when administering midazolam in the following populations High-risk patients include adults over 60 years of age, chronically ill or debilitated patients, which may include patients with chronic respiratory insufficiency, patients with chronic renal failure, impaired hepatic function or with impaired cardiac function, pediatric patients (especially those with cardiovascular instability). These high-risk patients require lower dosages and should be monitored on a continuous basis for early signs of alterations of vital functions, so that appropriate management may be administered. Mutagenesis Midazolam was negative for genotoxicity during in vitro and in vivo assays. Impairment of Fertility When midazolam (0, 1, 4, or 16 mg/kg) was given orally to male and female rats before and during mating and continuing in females throughout gestation and lactation, no adverse effects on male or female fertility were observed. Midazolam plasma exposures (AUC) at the highest dose tested were approximately 6 times that in humans at the recomended human dose. •Brand Names (Drug A): Aplenzin, Auvelity, Budeprion, Contrave, Forfivo, Wellbutrin, Zyban •Brand Names (Drug B): Buccolam, Busulfex, Nayzilam, Seizalam •Synonyms (Drug A): No synonyms listed •Synonyms (Drug B): No synonyms listed •Summary (Drug A): Bupropion is a norepinephrine and dopamine reuptake inhibitor used in the treatment of major depressive disorder (MDD), seasonal affective disorder (SAD), and as an aid to smoking cessation. •Summary (Drug B): Midazolam is a short-acting benzodiazepine with rapid onset that is commonly used in seizures, anesthesia and anxiety disorders. Output: As a positive modulator of GABAA receptor, midazolam can have a sedative effect on the central nervous system.5 Although the exact mechanism of action of midazolam has yet to be fully outlined, it has been observed to bind allosterically to the GABA receptor at the benzodiazepine site to increase the frequency of chloride channel opening, thus increasing the GABAergic neurotransmission. Additionally, midazolam can increase the affinity of GABA to its receptor. Chloride movement can hyperpolarize neurons, causing an increase in action potential threshold and thus reducing neuron firing frequency. As a result, the overall central nervous system activity is reduced. Therefore, the concomitant use of midazolam with another central nervous system depressant can potentiate each other's depressive effect, increasing the risk of sedation. The severity of the interaction is moderate.

Does Bupropion and Mifepristone interact?

•Drug A: Bupropion •Drug B: Mifepristone •Severity: MODERATE •Description: The serum concentration of Bupropion can be increased when it is combined with Mifepristone. •Extended Description: Mifepristone, when used chronically for hormonal conditions such as Cushing's syndrome, is an inhibitor of CYP2B6 hepatic enzyme and may cause significant increases in exposure of drugs that are metabolized by CYP2B6, such as bupropion. The risk for bupropion-induced adverse reactions, including nausea, dry mouth, restlessness or difficulty with sleep, seizures, hypertension, or neuropsychiatric effects may be enhanced when these agents are coadministered. •Indication (Drug A): Bupropion is indicated for the treatment of major depressive disorder (MDD), seasonal affective disorder (SAD), and as an aid to smoking cessation. When used in combination with naltrexone as the marketed product ContraveⓇ, bupropion is indicated as an adjunct to a reduced-calorie diet and increased physical activity for chronic weight management in adults with an initial body mass index (BMI) of: 30 kg/m^2 or greater (obese) or 27 kg/m^2 or greater (overweight) in the presence of at least one weight-related comorbid condition (e.g., hypertension, type 2 diabetes mellitus, or dyslipidemia). Bupropion is also used off-label as a first-line treatment in patients with ADHD and comorbid bipolar disorder when used as an adjunct to mood stabilizers. •Indication (Drug B): For the medical termination of intrauterine pregnancy through 49 days' pregnancy. Also indicated to control hyperglycemia secondary to hypercortisolism in adult patients with endogenous Cushing's syndrome who have type 2 diabetes mellitus or glucose intolerance and are not candidates for surgery or have had unsuccessful surgery. •Pharmacodynamics (Drug A): Bupropion is chemically unrelated to tricyclic, tetracyclic, selective serotonin re-uptake inhibitors, or other known antidepressant agents. Compared to classical tricyclic antidepressants, Bupropion is a relatively weak inhibitor of the neuronal uptake of norepinephrine and dopamine. In addition, Bupropion does not inhibit monoamine oxidase. Bupropion has been found to be essentially inactive at the serotonin transporter (SERT)(IC50 >10 000 nM), however both bupropion and its primary metabolite hydroxybupropion have been found to block the function of cation-selective serotonin type 3A receptors (5-HT3ARs). Bupropion produces dose-related central nervous system (CNS) stimulant effects in animals, as evidenced by increased locomotor activity, increased rates of responding in various schedule-controlled operant behaviour tasks, and, at high doses, induction of mild stereotyped behaviour. Due to these stimulant effects and selective activity at dopamine and norepinephrine receptors, bupropion has been identified as having an abuse potential. Bupropion has a similar structure to the controlled substance Cathinone, and has been identified as having mild amphetamine-like activity, particularly when inhaled or injected. Bupropion is also known to lower the seizure threshold, making any pre-existing seizure conditions a contraindication to its use. This risk is exacerbated when bupropion is combined with other drugs or substances that lower the seizure threshold, such as cocaine, or in clinical situations that would increase the risk of a seizure such as abrupt alcohol or benzodiazepine withdrawal. As norepinephrine has been shown to have anticonvulsant properties, bupropion's inhibitory effects on NET are thought to contribute to its pro-convulsant activity. Bupropion has been shown to increase blood pressure and pose a risk for exacerbation of unmanaged or pre-existing hypertension, however, clinical trials of bupropion in smokers with CVD have not identified an increased incidence of CV events including stroke or heart attack. In clinical trials, the mean increase in systolic blood pressure associated with the use of bupropion was found to be 1.3 mmHg. •Pharmacodynamics (Drug B): Mifepristone is a synthetic steroid with antiprogestational effects indicated for the medical termination of intrauterine pregnancy through 49 days' pregnancy. Doses of 1 mg/kg or greater of mifepristone have been shown to antagonize the endometrial and myometrial effects of progesterone in women. During pregnancy, the compound sensitizes the myometrium to the contraction-inducing activity of prostaglandins. Mifepristone also exhibits antiglucocorticoid and weak antiandrogenic activity. The activity of the glucocorticoid dexamethasone in rats was inhibited following doses of 10 to 25 mg/kg of mifepristone. Doses of 4.5 mg/kg or greater in human beings resulted in a compensatory elevation of adrenocorticotropic hormone (ACTH) and cortisol. •Mechanism of action (Drug A): Bupropion is a norepinephrine/dopamine-reuptake inhibitor (NDRI) that exerts its pharmacological effects by weakly inhibiting the enzymes involved in the uptake of the neurotransmitters norepinephrine and dopamine from the synaptic cleft, therefore prolonging their duration of action within the neuronal synapse and the downstream effects of these neurotransmitters. More specifically, bupropion binds to the norepinephrine transporter (NET) and the dopamine transporter (DAT). Bupropion was originally classified as an "atypical" antidepressant because it does not exert the same effects as the classical antidepressants such as Monoamine Oxidase Inhibitors (MAOIs), Tricyclic Antidepressants (TCAs), or Selective Serotonin Reuptake Inhibitors (SSRIs). While it has comparable effectiveness to typical first-line options for the treatment of depression such as SSRIs, bupropion is a unique option for the treatment of MDD as it lacks any clinically relevant serotonergic effects, typical of other mood medications, or any effects on histamine or adrenaline receptors. Lack of activity at these receptors results in a more tolerable side effect profile; bupropion is less likely to cause sexual side effects, sedation, or weight gain as compared to SSRIs or TCAs, for example. When used as an aid to smoking cessation, bupropion is thought to confer its anti-craving and anti-withdrawal effects by inhibiting dopamine reuptake, which is thought to be involved in the reward pathways associated with nicotine, and through the antagonism of the nicotinic acetylcholinergic receptor (AChR), thereby blunting the effects of nicotine. Furthermore, the stimulatory effects produced by bupropion in the central nervous system are similar to nicotine's effects, making low doses of bupropion a suitable option as a nicotine substitute. When used in combination with naltrexone in the marketed product ContraveⓇ for chronic weight management, the two components are thought to have effects on areas of the brain involved in the regulation of food intake. This includes the hypothalamus, which is involved in appetite regulation, and the mesolimbic dopamine circuit, which is involved in reward pathways. Studies have shown that the combined activity of bupropion and naltrexone increase the firing rate of hypothalamic pro-opiomelanocortin (POMC) neurons and blockade of opioid receptor-mediated POMC auto-inhibition, which are associated with a reduction in food intake and increased energy expenditure. This combination was also found to reduce food intake when injected directly into the ventral tegmental area of the mesolimbic circuit in mice, which is an area associated with the regulation of reward pathways. •Mechanism of action (Drug B): The anti-progestational activity of mifepristone results from competitive interaction with progesterone at progesterone-receptor sites. Based on studies with various oral doses in several animal species (mouse, rat, rabbit and monkey), the compound inhibits the activity of endogenous or exogenous progesterone. The termination of pregnancy results. In the treatment of Cushing's syndrome, Mifepristone blocks the binding of cortisol to its receptor. It does not decrease cortisol production but reduces the effects of excess cortisol, such as high blood sugar levels. •Absorption (Drug A): Bupropion is currently available in 3 distinct, but bioequivalent formulations: immediate release (IR), sustained-release (SR), and extended-release (XL). Immediate Release Formulation In humans, following oral administration of bupropion hydrochloride tablets, peak plasma bupropion concentrations are usually achieved within 2 hours. IR formulations provide a short duration of action and are therefore generally dosed three times per day. Sustained Release Formulation In humans, following oral administration of bupropion hydrochloride sustained-release tablets (SR), peak plasma concentration (Cmax) of bupropion is usually achieved within 3 hours. SR formulations provide a 12-hour extended release of medication and are therefore generally dosed twice per day. Extended Release Formulation Following single oral administration of bupropion hydrochloride extended-release tablets (XL) to healthy volunteers, the median time to peak plasma concentrations for bupropion was approximately 5 hours. The presence of food did not affect the peak concentration or area under the curve of bupropion. XL formulations provide a 24-hour extended release of medication and are therefore generally dosed once per day/ In a trial comparing chronic dosing with bupropion hydrochloride extended-release tablets (SR) 150 mg twice daily to bupropion immediate-release formulation 100 mg 3 times daily, the steady state Cmax for bupropion after bupropion hydrochloride sustained-release tablets (SR) administration was approximately 85% of those achieved after bupropion immediate-release formulation administration. Exposure (AUC) to bupropion was equivalent for both formulations. Bioequivalence was also demonstrated for all three major active metabolites (i.e., hydroxybupropion, threohydrobupropion and erythrohydrobupropion) for both Cmax and AUC. Thus, at steady state, bupropion hydrochloride sustained-release tablets (SR) given twice daily, and the immediate-release formulation of bupropion given 3 times daily, are essentially bioequivalent for both bupropion and the 3 quantitatively important metabolites. Furthermore, in a study comparing 14-day dosing with bupropion hydrochloride extended-release tablets (XL), 300 mg once-daily to the immediate-release formulation of bupropion at 100 mg 3 times daily, equivalence was demonstrated for peak plasma concentration and area under the curve for bupropion and the three metabolites (hydroxybupropion, threohydrobupropion, and erythrohydrobupropion). Additionally, in a study comparing 14-day dosing with bupropion hydrochloride extended-release tablets (XL) 300 mg once daily to the sustained-release formulation of bupropion at 150 mg 2 times daily, equivalence was demonstrated for peak plasma concentration and area under the curve for bupropion and the three metabolites. Bupropion hydrochloride extended-release tablets (SR) can be taken with or without food. Bupropion Cmax and AUC were increased by 11% to 35% and 16% to 19%, respectively, when bupropion hydrochloride extended-release tablets (SR) was administered with food to healthy volunteers in three trials. The food effect is not considered clinically significant. Following a single-dose administration of bupropion hydrochloride extended-release tablets (SR) in humans, Cmax of bupropion's metabolite hydroxybupropion occurs approximately 6 hours post-dose and is approximately 10 times the peak level of the parent drug at steady state. The elimination half-life of hydroxybupropion is approximately 20 (±5) hours and its AUC at steady state is about 17 times that of bupropion. The times to peak concentrations for the erythrohydrobupropion and threohydrobupropion metabolites are similar to that of the hydroxybupropion metabolite. However, their elimination half-lives are longer, 33(±10) and 37 (±13) hours, respectively, and steady-state AUCs are 1.5 and 7 times that of bupropion, respectively. •Absorption (Drug B): The absolute bioavailability of a 20 mg oral dose is 69% •Volume of distribution (Drug A): No volume of distribution available •Volume of distribution (Drug B): No volume of distribution available •Protein binding (Drug A): In vitro tests show that bupropion is 84% bound to human plasma proteins at concentrations up to 200 mcg per mL. The extent of protein binding of the hydroxybupropion metabolite is similar to that for bupropion, whereas the extent of protein binding of the threohydrobupropion metabolite is about half that seen with bupropion. •Protein binding (Drug B): 98% (bound to plasma proteins, albumin and a 1-acid glycoprotein) •Metabolism (Drug A): Bupropion is extensively metabolized in humans. Three metabolites are active: hydroxybupropion, which is formed via hydroxylation of the tert-butyl group of bupropion, and the amino-alcohol isomers, threohydrobupropion and erythrohydrobupropion, which are formed via reduction of the carbonyl group. In vitro findings suggest that CYP2B6 is the principal isoenzyme involved in the formation of hydroxybupropion, while cytochrome P450 enzymes are not involved in the formation of threohydrobupropion. Hydroxybupropion has been shown to have the same affinity as bupropion for the norepinephrine transporter (NET) but approximately 50% of its antidepressant activity despite reaching concentrations of ~10-fold higher than that of the parent drug. Oxidation of the bupropion side chain results in the formation of a glycine conjugate of meta-chlorobenzoic acid, which is then excreted as the major urinary metabolite. The potency and toxicity of the metabolites relative to bupropion have not been fully characterized. However, it has been demonstrated in an antidepressant screening test in mice that hydroxybupropion is one-half as potent as bupropion, while threohydrobupropion and erythrohydrobupropion are 5-fold less potent than bupropion. This may be of clinical importance because the plasma concentrations of the metabolites are as high as or higher than those of bupropion. Bupropion and its metabolites exhibit linear kinetics following chronic administration of 300 to 450 mg per day. •Metabolism (Drug B): Hepatic. Hepatic, by Cytochrome P450 3A4 isoenzyme to the N-monodemethylated metabolite (RU 42 633); RU 42 698, which results from the loss of two methyl groups from position 11 beta; and RU 42 698, which results from terminal hydroxylation of the 17–propynyl chain. •Route of elimination (Drug A): Bupropion is extensively metabolized in humans. Oxidation of the bupropion side chain results in the formation of a glycine conjugate of metachlorobenzoic acid, which is then excreted as the major urinary metabolite. Following oral administration of 200 mg of 14C-bupropion in humans, 87% and 10% of the radioactive dose were recovered in the urine and feces, respectively. However, the fraction of the oral dose of bupropion excreted unchanged was only 0.5%, a finding consistent with the extensive metabolism of bupropion. •Route of elimination (Drug B): Fecal: 83%; Renal: 9%. •Half-life (Drug A): 24 hours •Half-life (Drug B): 18 hours •Clearance (Drug A): No clearance available •Clearance (Drug B): No clearance available •Toxicity (Drug A): Symptoms of overdose include seizures, hallucinations, loss of consciousness, tachycardia, and cardiac arrest. •Toxicity (Drug B): Nearly all of the women who receive mifepristone will report adverse reactions, and many can be expected to report more than one such reaction. About 90% of patients report adverse reactions following administration of misoprostol on day three of the treatment procedure. Side effects include more heavy bleeding than a heavy menstrual period, abdominal pain, uterine cramping, nausea, vomiting, and diarrhea. •Brand Names (Drug A): Aplenzin, Auvelity, Budeprion, Contrave, Forfivo, Wellbutrin, Zyban •Brand Names (Drug B): Korlym, Mifegymiso •Synonyms (Drug A): No synonyms listed •Synonyms (Drug B): No synonyms listed •Summary (Drug A): Bupropion is a norepinephrine and dopamine reuptake inhibitor used in the treatment of major depressive disorder (MDD), seasonal affective disorder (SAD), and as an aid to smoking cessation. •Summary (Drug B): Mifepristone is a cortisol receptor blocker used to treat Cushing's syndrome, and to terminate pregnancies up to 70 days gestation.

Mifepristone, when used chronically for hormonal conditions such as Cushing's syndrome, is an inhibitor of CYP2B6 hepatic enzyme and may cause significant increases in exposure of drugs that are metabolized by CYP2B6, such as bupropion. The risk for bupropion-induced adverse reactions, including nausea, dry mouth, restlessness or difficulty with sleep, seizures, hypertension, or neuropsychiatric effects may be enhanced when these agents are coadministered. The severity of the interaction is moderate.

Question: Does Bupropion and Mifepristone interact? Information: •Drug A: Bupropion •Drug B: Mifepristone •Severity: MODERATE •Description: The serum concentration of Bupropion can be increased when it is combined with Mifepristone. •Extended Description: Mifepristone, when used chronically for hormonal conditions such as Cushing's syndrome, is an inhibitor of CYP2B6 hepatic enzyme and may cause significant increases in exposure of drugs that are metabolized by CYP2B6, such as bupropion. The risk for bupropion-induced adverse reactions, including nausea, dry mouth, restlessness or difficulty with sleep, seizures, hypertension, or neuropsychiatric effects may be enhanced when these agents are coadministered. •Indication (Drug A): Bupropion is indicated for the treatment of major depressive disorder (MDD), seasonal affective disorder (SAD), and as an aid to smoking cessation. When used in combination with naltrexone as the marketed product ContraveⓇ, bupropion is indicated as an adjunct to a reduced-calorie diet and increased physical activity for chronic weight management in adults with an initial body mass index (BMI) of: 30 kg/m^2 or greater (obese) or 27 kg/m^2 or greater (overweight) in the presence of at least one weight-related comorbid condition (e.g., hypertension, type 2 diabetes mellitus, or dyslipidemia). Bupropion is also used off-label as a first-line treatment in patients with ADHD and comorbid bipolar disorder when used as an adjunct to mood stabilizers. •Indication (Drug B): For the medical termination of intrauterine pregnancy through 49 days' pregnancy. Also indicated to control hyperglycemia secondary to hypercortisolism in adult patients with endogenous Cushing's syndrome who have type 2 diabetes mellitus or glucose intolerance and are not candidates for surgery or have had unsuccessful surgery. •Pharmacodynamics (Drug A): Bupropion is chemically unrelated to tricyclic, tetracyclic, selective serotonin re-uptake inhibitors, or other known antidepressant agents. Compared to classical tricyclic antidepressants, Bupropion is a relatively weak inhibitor of the neuronal uptake of norepinephrine and dopamine. In addition, Bupropion does not inhibit monoamine oxidase. Bupropion has been found to be essentially inactive at the serotonin transporter (SERT)(IC50 >10 000 nM), however both bupropion and its primary metabolite hydroxybupropion have been found to block the function of cation-selective serotonin type 3A receptors (5-HT3ARs). Bupropion produces dose-related central nervous system (CNS) stimulant effects in animals, as evidenced by increased locomotor activity, increased rates of responding in various schedule-controlled operant behaviour tasks, and, at high doses, induction of mild stereotyped behaviour. Due to these stimulant effects and selective activity at dopamine and norepinephrine receptors, bupropion has been identified as having an abuse potential. Bupropion has a similar structure to the controlled substance Cathinone, and has been identified as having mild amphetamine-like activity, particularly when inhaled or injected. Bupropion is also known to lower the seizure threshold, making any pre-existing seizure conditions a contraindication to its use. This risk is exacerbated when bupropion is combined with other drugs or substances that lower the seizure threshold, such as cocaine, or in clinical situations that would increase the risk of a seizure such as abrupt alcohol or benzodiazepine withdrawal. As norepinephrine has been shown to have anticonvulsant properties, bupropion's inhibitory effects on NET are thought to contribute to its pro-convulsant activity. Bupropion has been shown to increase blood pressure and pose a risk for exacerbation of unmanaged or pre-existing hypertension, however, clinical trials of bupropion in smokers with CVD have not identified an increased incidence of CV events including stroke or heart attack. In clinical trials, the mean increase in systolic blood pressure associated with the use of bupropion was found to be 1.3 mmHg. •Pharmacodynamics (Drug B): Mifepristone is a synthetic steroid with antiprogestational effects indicated for the medical termination of intrauterine pregnancy through 49 days' pregnancy. Doses of 1 mg/kg or greater of mifepristone have been shown to antagonize the endometrial and myometrial effects of progesterone in women. During pregnancy, the compound sensitizes the myometrium to the contraction-inducing activity of prostaglandins. Mifepristone also exhibits antiglucocorticoid and weak antiandrogenic activity. The activity of the glucocorticoid dexamethasone in rats was inhibited following doses of 10 to 25 mg/kg of mifepristone. Doses of 4.5 mg/kg or greater in human beings resulted in a compensatory elevation of adrenocorticotropic hormone (ACTH) and cortisol. •Mechanism of action (Drug A): Bupropion is a norepinephrine/dopamine-reuptake inhibitor (NDRI) that exerts its pharmacological effects by weakly inhibiting the enzymes involved in the uptake of the neurotransmitters norepinephrine and dopamine from the synaptic cleft, therefore prolonging their duration of action within the neuronal synapse and the downstream effects of these neurotransmitters. More specifically, bupropion binds to the norepinephrine transporter (NET) and the dopamine transporter (DAT). Bupropion was originally classified as an "atypical" antidepressant because it does not exert the same effects as the classical antidepressants such as Monoamine Oxidase Inhibitors (MAOIs), Tricyclic Antidepressants (TCAs), or Selective Serotonin Reuptake Inhibitors (SSRIs). While it has comparable effectiveness to typical first-line options for the treatment of depression such as SSRIs, bupropion is a unique option for the treatment of MDD as it lacks any clinically relevant serotonergic effects, typical of other mood medications, or any effects on histamine or adrenaline receptors. Lack of activity at these receptors results in a more tolerable side effect profile; bupropion is less likely to cause sexual side effects, sedation, or weight gain as compared to SSRIs or TCAs, for example. When used as an aid to smoking cessation, bupropion is thought to confer its anti-craving and anti-withdrawal effects by inhibiting dopamine reuptake, which is thought to be involved in the reward pathways associated with nicotine, and through the antagonism of the nicotinic acetylcholinergic receptor (AChR), thereby blunting the effects of nicotine. Furthermore, the stimulatory effects produced by bupropion in the central nervous system are similar to nicotine's effects, making low doses of bupropion a suitable option as a nicotine substitute. When used in combination with naltrexone in the marketed product ContraveⓇ for chronic weight management, the two components are thought to have effects on areas of the brain involved in the regulation of food intake. This includes the hypothalamus, which is involved in appetite regulation, and the mesolimbic dopamine circuit, which is involved in reward pathways. Studies have shown that the combined activity of bupropion and naltrexone increase the firing rate of hypothalamic pro-opiomelanocortin (POMC) neurons and blockade of opioid receptor-mediated POMC auto-inhibition, which are associated with a reduction in food intake and increased energy expenditure. This combination was also found to reduce food intake when injected directly into the ventral tegmental area of the mesolimbic circuit in mice, which is an area associated with the regulation of reward pathways. •Mechanism of action (Drug B): The anti-progestational activity of mifepristone results from competitive interaction with progesterone at progesterone-receptor sites. Based on studies with various oral doses in several animal species (mouse, rat, rabbit and monkey), the compound inhibits the activity of endogenous or exogenous progesterone. The termination of pregnancy results. In the treatment of Cushing's syndrome, Mifepristone blocks the binding of cortisol to its receptor. It does not decrease cortisol production but reduces the effects of excess cortisol, such as high blood sugar levels. •Absorption (Drug A): Bupropion is currently available in 3 distinct, but bioequivalent formulations: immediate release (IR), sustained-release (SR), and extended-release (XL). Immediate Release Formulation In humans, following oral administration of bupropion hydrochloride tablets, peak plasma bupropion concentrations are usually achieved within 2 hours. IR formulations provide a short duration of action and are therefore generally dosed three times per day. Sustained Release Formulation In humans, following oral administration of bupropion hydrochloride sustained-release tablets (SR), peak plasma concentration (Cmax) of bupropion is usually achieved within 3 hours. SR formulations provide a 12-hour extended release of medication and are therefore generally dosed twice per day. Extended Release Formulation Following single oral administration of bupropion hydrochloride extended-release tablets (XL) to healthy volunteers, the median time to peak plasma concentrations for bupropion was approximately 5 hours. The presence of food did not affect the peak concentration or area under the curve of bupropion. XL formulations provide a 24-hour extended release of medication and are therefore generally dosed once per day/ In a trial comparing chronic dosing with bupropion hydrochloride extended-release tablets (SR) 150 mg twice daily to bupropion immediate-release formulation 100 mg 3 times daily, the steady state Cmax for bupropion after bupropion hydrochloride sustained-release tablets (SR) administration was approximately 85% of those achieved after bupropion immediate-release formulation administration. Exposure (AUC) to bupropion was equivalent for both formulations. Bioequivalence was also demonstrated for all three major active metabolites (i.e., hydroxybupropion, threohydrobupropion and erythrohydrobupropion) for both Cmax and AUC. Thus, at steady state, bupropion hydrochloride sustained-release tablets (SR) given twice daily, and the immediate-release formulation of bupropion given 3 times daily, are essentially bioequivalent for both bupropion and the 3 quantitatively important metabolites. Furthermore, in a study comparing 14-day dosing with bupropion hydrochloride extended-release tablets (XL), 300 mg once-daily to the immediate-release formulation of bupropion at 100 mg 3 times daily, equivalence was demonstrated for peak plasma concentration and area under the curve for bupropion and the three metabolites (hydroxybupropion, threohydrobupropion, and erythrohydrobupropion). Additionally, in a study comparing 14-day dosing with bupropion hydrochloride extended-release tablets (XL) 300 mg once daily to the sustained-release formulation of bupropion at 150 mg 2 times daily, equivalence was demonstrated for peak plasma concentration and area under the curve for bupropion and the three metabolites. Bupropion hydrochloride extended-release tablets (SR) can be taken with or without food. Bupropion Cmax and AUC were increased by 11% to 35% and 16% to 19%, respectively, when bupropion hydrochloride extended-release tablets (SR) was administered with food to healthy volunteers in three trials. The food effect is not considered clinically significant. Following a single-dose administration of bupropion hydrochloride extended-release tablets (SR) in humans, Cmax of bupropion's metabolite hydroxybupropion occurs approximately 6 hours post-dose and is approximately 10 times the peak level of the parent drug at steady state. The elimination half-life of hydroxybupropion is approximately 20 (±5) hours and its AUC at steady state is about 17 times that of bupropion. The times to peak concentrations for the erythrohydrobupropion and threohydrobupropion metabolites are similar to that of the hydroxybupropion metabolite. However, their elimination half-lives are longer, 33(±10) and 37 (±13) hours, respectively, and steady-state AUCs are 1.5 and 7 times that of bupropion, respectively. •Absorption (Drug B): The absolute bioavailability of a 20 mg oral dose is 69% •Volume of distribution (Drug A): No volume of distribution available •Volume of distribution (Drug B): No volume of distribution available •Protein binding (Drug A): In vitro tests show that bupropion is 84% bound to human plasma proteins at concentrations up to 200 mcg per mL. The extent of protein binding of the hydroxybupropion metabolite is similar to that for bupropion, whereas the extent of protein binding of the threohydrobupropion metabolite is about half that seen with bupropion. •Protein binding (Drug B): 98% (bound to plasma proteins, albumin and a 1-acid glycoprotein) •Metabolism (Drug A): Bupropion is extensively metabolized in humans. Three metabolites are active: hydroxybupropion, which is formed via hydroxylation of the tert-butyl group of bupropion, and the amino-alcohol isomers, threohydrobupropion and erythrohydrobupropion, which are formed via reduction of the carbonyl group. In vitro findings suggest that CYP2B6 is the principal isoenzyme involved in the formation of hydroxybupropion, while cytochrome P450 enzymes are not involved in the formation of threohydrobupropion. Hydroxybupropion has been shown to have the same affinity as bupropion for the norepinephrine transporter (NET) but approximately 50% of its antidepressant activity despite reaching concentrations of ~10-fold higher than that of the parent drug. Oxidation of the bupropion side chain results in the formation of a glycine conjugate of meta-chlorobenzoic acid, which is then excreted as the major urinary metabolite. The potency and toxicity of the metabolites relative to bupropion have not been fully characterized. However, it has been demonstrated in an antidepressant screening test in mice that hydroxybupropion is one-half as potent as bupropion, while threohydrobupropion and erythrohydrobupropion are 5-fold less potent than bupropion. This may be of clinical importance because the plasma concentrations of the metabolites are as high as or higher than those of bupropion. Bupropion and its metabolites exhibit linear kinetics following chronic administration of 300 to 450 mg per day. •Metabolism (Drug B): Hepatic. Hepatic, by Cytochrome P450 3A4 isoenzyme to the N-monodemethylated metabolite (RU 42 633); RU 42 698, which results from the loss of two methyl groups from position 11 beta; and RU 42 698, which results from terminal hydroxylation of the 17–propynyl chain. •Route of elimination (Drug A): Bupropion is extensively metabolized in humans. Oxidation of the bupropion side chain results in the formation of a glycine conjugate of metachlorobenzoic acid, which is then excreted as the major urinary metabolite. Following oral administration of 200 mg of 14C-bupropion in humans, 87% and 10% of the radioactive dose were recovered in the urine and feces, respectively. However, the fraction of the oral dose of bupropion excreted unchanged was only 0.5%, a finding consistent with the extensive metabolism of bupropion. •Route of elimination (Drug B): Fecal: 83%; Renal: 9%. •Half-life (Drug A): 24 hours •Half-life (Drug B): 18 hours •Clearance (Drug A): No clearance available •Clearance (Drug B): No clearance available •Toxicity (Drug A): Symptoms of overdose include seizures, hallucinations, loss of consciousness, tachycardia, and cardiac arrest. •Toxicity (Drug B): Nearly all of the women who receive mifepristone will report adverse reactions, and many can be expected to report more than one such reaction. About 90% of patients report adverse reactions following administration of misoprostol on day three of the treatment procedure. Side effects include more heavy bleeding than a heavy menstrual period, abdominal pain, uterine cramping, nausea, vomiting, and diarrhea. •Brand Names (Drug A): Aplenzin, Auvelity, Budeprion, Contrave, Forfivo, Wellbutrin, Zyban •Brand Names (Drug B): Korlym, Mifegymiso •Synonyms (Drug A): No synonyms listed •Synonyms (Drug B): No synonyms listed •Summary (Drug A): Bupropion is a norepinephrine and dopamine reuptake inhibitor used in the treatment of major depressive disorder (MDD), seasonal affective disorder (SAD), and as an aid to smoking cessation. •Summary (Drug B): Mifepristone is a cortisol receptor blocker used to treat Cushing's syndrome, and to terminate pregnancies up to 70 days gestation. Output: Mifepristone, when used chronically for hormonal conditions such as Cushing's syndrome, is an inhibitor of CYP2B6 hepatic enzyme and may cause significant increases in exposure of drugs that are metabolized by CYP2B6, such as bupropion. The risk for bupropion-induced adverse reactions, including nausea, dry mouth, restlessness or difficulty with sleep, seizures, hypertension, or neuropsychiatric effects may be enhanced when these agents are coadministered. The severity of the interaction is moderate.

Does Bupropion and Migalastat interact?

•Drug A: Bupropion •Drug B: Migalastat •Severity: MINOR •Description: Bupropion may decrease the excretion rate of Migalastat which could result in a higher serum level. •Extended Description: The renal excretion of drugs is the overall result of a combination of kidney processes that include glomerular filtration, passive diffusion, tubular secretion, and tubular reabsorption. Since two of these mechanisms - tubular secretion and reabsorption - are saturable processes , they are consequently susceptible to competition between multiple substrates excreted by the kidneys. If two or more medications that are mainly renally excreted are co-administered, they may compete for renal elimination; there is a large likelihood that one agent may "out-compete" or saturate the renal excretion mechanisms before the other concomitantly administered agent(s) are excreted. As a result, the elimination of these other concurrently administered agents may be inhibited or otherwise delayed, which could lead to increases in their serum concentrations and the risk, incidence, and/or severity of adverse effects associated with the exposure to such drugs. •Indication (Drug A): Bupropion is indicated for the treatment of major depressive disorder (MDD), seasonal affective disorder (SAD), and as an aid to smoking cessation. When used in combination with naltrexone as the marketed product ContraveⓇ, bupropion is indicated as an adjunct to a reduced-calorie diet and increased physical activity for chronic weight management in adults with an initial body mass index (BMI) of: 30 kg/m^2 or greater (obese) or 27 kg/m^2 or greater (overweight) in the presence of at least one weight-related comorbid condition (e.g., hypertension, type 2 diabetes mellitus, or dyslipidemia). Bupropion is also used off-label as a first-line treatment in patients with ADHD and comorbid bipolar disorder when used as an adjunct to mood stabilizers. •Indication (Drug B): Migalastat is approved by the FDA for the treatment of adults with a confirmed diagnosis of Fabry disease and an amenable galactosidase alpha gene (GLA) variant based on in vitro assay data. This indication is approved under accelerated approval based on a reduction in kidney interstitial capillary cell globotriaosylceramide (KIC GL-3) substrate. Continued approval for this indication may be contingent upon verification and description of clinical benefit in confirmatory trials. Migalastat is also approved by the EMA and Health Canada to treat the same disease, although it is approved for both adults and adolescents aged 16 years and older in Europe. •Pharmacodynamics (Drug A): Bupropion is chemically unrelated to tricyclic, tetracyclic, selective serotonin re-uptake inhibitors, or other known antidepressant agents. Compared to classical tricyclic antidepressants, Bupropion is a relatively weak inhibitor of the neuronal uptake of norepinephrine and dopamine. In addition, Bupropion does not inhibit monoamine oxidase. Bupropion has been found to be essentially inactive at the serotonin transporter (SERT)(IC50 >10 000 nM), however both bupropion and its primary metabolite hydroxybupropion have been found to block the function of cation-selective serotonin type 3A receptors (5-HT3ARs). Bupropion produces dose-related central nervous system (CNS) stimulant effects in animals, as evidenced by increased locomotor activity, increased rates of responding in various schedule-controlled operant behaviour tasks, and, at high doses, induction of mild stereotyped behaviour. Due to these stimulant effects and selective activity at dopamine and norepinephrine receptors, bupropion has been identified as having an abuse potential. Bupropion has a similar structure to the controlled substance Cathinone, and has been identified as having mild amphetamine-like activity, particularly when inhaled or injected. Bupropion is also known to lower the seizure threshold, making any pre-existing seizure conditions a contraindication to its use. This risk is exacerbated when bupropion is combined with other drugs or substances that lower the seizure threshold, such as cocaine, or in clinical situations that would increase the risk of a seizure such as abrupt alcohol or benzodiazepine withdrawal. As norepinephrine has been shown to have anticonvulsant properties, bupropion's inhibitory effects on NET are thought to contribute to its pro-convulsant activity. Bupropion has been shown to increase blood pressure and pose a risk for exacerbation of unmanaged or pre-existing hypertension, however, clinical trials of bupropion in smokers with CVD have not identified an increased incidence of CV events including stroke or heart attack. In clinical trials, the mean increase in systolic blood pressure associated with the use of bupropion was found to be 1.3 mmHg. •Pharmacodynamics (Drug B): In general, treatment in patients with migalastat in Phase 2 pharmacodynamic trials resulted in increases in endogenous alpha-galactosidase (alpha-Gal A) activity in white blood cells, as well as in skin and kidney for the majority of patients. In patients with amenable galactosidase alpha gene (GLA) mutations, globotriaosylceramide (GL-3) levels tended to decrease in the urine and in the kidney interstitial capillaries. In an in vitro assay (HEK-293 assay), Human Embryonic Kidney (HEK-293) cell lines were transfected with specific GLA variants (mutations) which produced mutant alpha-Gal A proteins. In the transfected cells, amenability of the GLA variants was assessed after a 5-day incubation with 10 micromol/L migalastat. A GLA variant was categorized as amenable if the resultant mutant alpha-Gal A activity (measured in the cell lysates) met two criteria: 1) it showed a relative increase of at least 20% compared to the pre-treatment alpha-Gal A activity, and 2) it showed an absolute increase of at least 3% of the wild-type (normal) alpha-Gal activity. The in vitro assay did not evaluate the trafficking of the mutant alpha-Gal A proteins into the lysosome or the dissociation of migalastat from the mutant alpha-Gal A proteins within the lysosome. Also, the in vitro assay did not test whether a GLA variant causes Fabry disease or not. •Mechanism of action (Drug A): Bupropion is a norepinephrine/dopamine-reuptake inhibitor (NDRI) that exerts its pharmacological effects by weakly inhibiting the enzymes involved in the uptake of the neurotransmitters norepinephrine and dopamine from the synaptic cleft, therefore prolonging their duration of action within the neuronal synapse and the downstream effects of these neurotransmitters. More specifically, bupropion binds to the norepinephrine transporter (NET) and the dopamine transporter (DAT). Bupropion was originally classified as an "atypical" antidepressant because it does not exert the same effects as the classical antidepressants such as Monoamine Oxidase Inhibitors (MAOIs), Tricyclic Antidepressants (TCAs), or Selective Serotonin Reuptake Inhibitors (SSRIs). While it has comparable effectiveness to typical first-line options for the treatment of depression such as SSRIs, bupropion is a unique option for the treatment of MDD as it lacks any clinically relevant serotonergic effects, typical of other mood medications, or any effects on histamine or adrenaline receptors. Lack of activity at these receptors results in a more tolerable side effect profile; bupropion is less likely to cause sexual side effects, sedation, or weight gain as compared to SSRIs or TCAs, for example. When used as an aid to smoking cessation, bupropion is thought to confer its anti-craving and anti-withdrawal effects by inhibiting dopamine reuptake, which is thought to be involved in the reward pathways associated with nicotine, and through the antagonism of the nicotinic acetylcholinergic receptor (AChR), thereby blunting the effects of nicotine. Furthermore, the stimulatory effects produced by bupropion in the central nervous system are similar to nicotine's effects, making low doses of bupropion a suitable option as a nicotine substitute. When used in combination with naltrexone in the marketed product ContraveⓇ for chronic weight management, the two components are thought to have effects on areas of the brain involved in the regulation of food intake. This includes the hypothalamus, which is involved in appetite regulation, and the mesolimbic dopamine circuit, which is involved in reward pathways. Studies have shown that the combined activity of bupropion and naltrexone increase the firing rate of hypothalamic pro-opiomelanocortin (POMC) neurons and blockade of opioid receptor-mediated POMC auto-inhibition, which are associated with a reduction in food intake and increased energy expenditure. This combination was also found to reduce food intake when injected directly into the ventral tegmental area of the mesolimbic circuit in mice, which is an area associated with the regulation of reward pathways. •Mechanism of action (Drug B): Fabry disease is a progressive X-linked lysosomal storage disorder that affects males and females. Fabry disease-causing mutations occur in the galactosidase alpha (GLA) gene and result in a deficiency of the lysosomal enzyme alpha-galactosidase A (alpha-Gal A) that is required for glycosphingolipid substrate (GL-3 and lyso-Gb3) metabolism. Reduced alpha-Gal A activity is, therefore, associated with the progressive accumulation of glycosphingolipid substrate in vulnerable organs and tissues, which ultimately leads to the morbidity and mortality associated with Fabry disease. Migalastat is a pharmacological chaperone that reversibly binds to the active site of the alpha-galactosidase A (alpha-Gal A) protein (encoded by the galactosidase alpha gene, GLA), which is deficient in Fabry disease. This binding stabilizes alpha-Gal A allowing its trafficking from the endoplasmic reticulum into the lysosome where it exerts its action. In the lysosome, at a lower pH and at a higher concentration of relevant substrates, migalastat dissociates from alpha-Gal A allowing it to break down the glycosphingolipids globotriaosylceramide (GL-3) and globotriaosylsphingosine (lyso-Gb3). Certain GLA variants (mutations) causing Fabry disease result in the production of abnormally folded and less stable forms of the alpha-Gal A protein which, however, retain enzymatic activity. Those GLA variants, referred to as amenable variants, produce alpha-Gal A proteins that may be stabilized by migalastat thereby restoring their trafficking to lysosomes and their intralysosomal activity. The GLA mutations that are amenable and not amenable to treatment with migalastat are regularly maintained and updated on online sites that are readily accessible by healthcare providers. •Absorption (Drug A): Bupropion is currently available in 3 distinct, but bioequivalent formulations: immediate release (IR), sustained-release (SR), and extended-release (XL). Immediate Release Formulation In humans, following oral administration of bupropion hydrochloride tablets, peak plasma bupropion concentrations are usually achieved within 2 hours. IR formulations provide a short duration of action and are therefore generally dosed three times per day. Sustained Release Formulation In humans, following oral administration of bupropion hydrochloride sustained-release tablets (SR), peak plasma concentration (Cmax) of bupropion is usually achieved within 3 hours. SR formulations provide a 12-hour extended release of medication and are therefore generally dosed twice per day. Extended Release Formulation Following single oral administration of bupropion hydrochloride extended-release tablets (XL) to healthy volunteers, the median time to peak plasma concentrations for bupropion was approximately 5 hours. The presence of food did not affect the peak concentration or area under the curve of bupropion. XL formulations provide a 24-hour extended release of medication and are therefore generally dosed once per day/ In a trial comparing chronic dosing with bupropion hydrochloride extended-release tablets (SR) 150 mg twice daily to bupropion immediate-release formulation 100 mg 3 times daily, the steady state Cmax for bupropion after bupropion hydrochloride sustained-release tablets (SR) administration was approximately 85% of those achieved after bupropion immediate-release formulation administration. Exposure (AUC) to bupropion was equivalent for both formulations. Bioequivalence was also demonstrated for all three major active metabolites (i.e., hydroxybupropion, threohydrobupropion and erythrohydrobupropion) for both Cmax and AUC. Thus, at steady state, bupropion hydrochloride sustained-release tablets (SR) given twice daily, and the immediate-release formulation of bupropion given 3 times daily, are essentially bioequivalent for both bupropion and the 3 quantitatively important metabolites. Furthermore, in a study comparing 14-day dosing with bupropion hydrochloride extended-release tablets (XL), 300 mg once-daily to the immediate-release formulation of bupropion at 100 mg 3 times daily, equivalence was demonstrated for peak plasma concentration and area under the curve for bupropion and the three metabolites (hydroxybupropion, threohydrobupropion, and erythrohydrobupropion). Additionally, in a study comparing 14-day dosing with bupropion hydrochloride extended-release tablets (XL) 300 mg once daily to the sustained-release formulation of bupropion at 150 mg 2 times daily, equivalence was demonstrated for peak plasma concentration and area under the curve for bupropion and the three metabolites. Bupropion hydrochloride extended-release tablets (SR) can be taken with or without food. Bupropion Cmax and AUC were increased by 11% to 35% and 16% to 19%, respectively, when bupropion hydrochloride extended-release tablets (SR) was administered with food to healthy volunteers in three trials. The food effect is not considered clinically significant. Following a single-dose administration of bupropion hydrochloride extended-release tablets (SR) in humans, Cmax of bupropion's metabolite hydroxybupropion occurs approximately 6 hours post-dose and is approximately 10 times the peak level of the parent drug at steady state. The elimination half-life of hydroxybupropion is approximately 20 (±5) hours and its AUC at steady state is about 17 times that of bupropion. The times to peak concentrations for the erythrohydrobupropion and threohydrobupropion metabolites are similar to that of the hydroxybupropion metabolite. However, their elimination half-lives are longer, 33(±10) and 37 (±13) hours, respectively, and steady-state AUCs are 1.5 and 7 times that of bupropion, respectively. •Absorption (Drug B): With absorption occurring largely in the gut, the absolute bioavailability (AUC) for a single oral 150 mg migalastat hydrochloride dose or a single 2-hour 150 mg intravenous infusion was approximately 75% and T max was approximately 3 hours. Plasma migalastat exposure (AUC 0-∞ ) and Cmax demonstrated dose-proportional increases at migalastat hydrochloride oral doses from 50 mg to 1,250 mg (doses from 0.5 to 8.3-fold of the approved recommended dosage). Migalastat administered with a high-fat meal (850 calories; 56% from fat), or 1 hour before a high-fat or light meal (507 calories; 30% from fat), or 1 hour after a light meal, resulted in significant reductions of 37% to 42% in mean total migalastat exposure (AUC 0-∞ ) and reductions of 15% to 39% in mean peak migalastat exposure (Cmax) compared with the fasting state. •Volume of distribution (Drug A): No volume of distribution available •Volume of distribution (Drug B): In healthy volunteers, the volume of distribution (Vz/F) of migalastat following ascending single oral doses (25-675 mg migalastat HCl) ranged from 77 to 133 L, indicating it is well distributed into tissues and greater than total body water (42 liters). •Protein binding (Drug A): In vitro tests show that bupropion is 84% bound to human plasma proteins at concentrations up to 200 mcg per mL. The extent of protein binding of the hydroxybupropion metabolite is similar to that for bupropion, whereas the extent of protein binding of the threohydrobupropion metabolite is about half that seen with bupropion. •Protein binding (Drug B): There was no detectable plasma protein binding following administration of [14C]-migalastat hydrochloride in the concentration range between 1 and 100 µM. •Metabolism (Drug A): Bupropion is extensively metabolized in humans. Three metabolites are active: hydroxybupropion, which is formed via hydroxylation of the tert-butyl group of bupropion, and the amino-alcohol isomers, threohydrobupropion and erythrohydrobupropion, which are formed via reduction of the carbonyl group. In vitro findings suggest that CYP2B6 is the principal isoenzyme involved in the formation of hydroxybupropion, while cytochrome P450 enzymes are not involved in the formation of threohydrobupropion. Hydroxybupropion has been shown to have the same affinity as bupropion for the norepinephrine transporter (NET) but approximately 50% of its antidepressant activity despite reaching concentrations of ~10-fold higher than that of the parent drug. Oxidation of the bupropion side chain results in the formation of a glycine conjugate of meta-chlorobenzoic acid, which is then excreted as the major urinary metabolite. The potency and toxicity of the metabolites relative to bupropion have not been fully characterized. However, it has been demonstrated in an antidepressant screening test in mice that hydroxybupropion is one-half as potent as bupropion, while threohydrobupropion and erythrohydrobupropion are 5-fold less potent than bupropion. This may be of clinical importance because the plasma concentrations of the metabolites are as high as or higher than those of bupropion. Bupropion and its metabolites exhibit linear kinetics following chronic administration of 300 to 450 mg per day. •Metabolism (Drug B): Based upon in vivo data, migalastat is a substrate for uridine diphosphate glucuronosyltransferase (otherwise known as UGT or UDPGT), being a minor elimination pathway. •Route of elimination (Drug A): Bupropion is extensively metabolized in humans. Oxidation of the bupropion side chain results in the formation of a glycine conjugate of metachlorobenzoic acid, which is then excreted as the major urinary metabolite. Following oral administration of 200 mg of 14C-bupropion in humans, 87% and 10% of the radioactive dose were recovered in the urine and feces, respectively. However, the fraction of the oral dose of bupropion excreted unchanged was only 0.5%, a finding consistent with the extensive metabolism of bupropion. •Route of elimination (Drug B): In a mass balance study in healthy male subjects, following oral administration of 123 mg [14C]-migalastat, approximately 77% of the total radiolabeled dose was recovered in urine and 20% of the total radiolabeled dose was recovered in feces with an overall total recovery of 98% within 96 hours post-dose. In urine, unchanged migalastat accounted for 80% of the radioactivity, which equates to 62% of the administered dose. In feces, unchanged migalastat was the only drug-related component. In plasma, unchanged migalastat accounted for approximately 77% of the plasma radioactivity, and three dehydrogenated O-glucuronide conjugated metabolites, M1 to M3, together accounted for approximately 13% of the plasma radioactivity, none of which comprised more than 6% of the radiolabeled dose. Approximately 9% of the total radioactivity in plasma was unassigned. •Half-life (Drug A): 24 hours •Half-life (Drug B): The mean elimination half-life (t1/2) of migalastat ranges from approximately 3 to 5 hours for a single oral dose of 150 mg. For the dose of 123 mg, the mean elimination half-life was estimated to be 4 hours. •Clearance (Drug A): No clearance available •Clearance (Drug B): Following ascending single oral doses (25-675 mg migalastat hydrochloride), no trends were found for clearance (CL/F). At the 150 mg dose, CL/F was approximately 11 to 14 L/hr, while at 123 mg, the apparent clearance was calculated to be 12.5 L/hr. •Toxicity (Drug A): Symptoms of overdose include seizures, hallucinations, loss of consciousness, tachycardia, and cardiac arrest. •Toxicity (Drug B): The most common adverse reactions reported with migalastat (≥ 10%) during the 6-month placebo-controlled, double-blind phase of its Study 1 clinical studies were headache, nasopharyngitis, urinary tract infection, nausea, and pyrexia. In case of overdose, general medical care is recommended. Headache and dizziness were the most common adverse reactions reported at doses of migalastat of up to 1250 mg and 2000 mg, respectively. •Brand Names (Drug A): Aplenzin, Auvelity, Budeprion, Contrave, Forfivo, Wellbutrin, Zyban •Brand Names (Drug B): Galafold •Synonyms (Drug A): No synonyms listed •Synonyms (Drug B): No synonyms listed •Summary (Drug A): Bupropion is a norepinephrine and dopamine reuptake inhibitor used in the treatment of major depressive disorder (MDD), seasonal affective disorder (SAD), and as an aid to smoking cessation. •Summary (Drug B): Migalastat is an alpha-galactosidase A chaperone used for the treatment of Fabry disease in patients with an amenable galactosidase alpha gene (GLA) variant.

The renal excretion of drugs is the overall result of a combination of kidney processes that include glomerular filtration, passive diffusion, tubular secretion, and tubular reabsorption. Since two of these mechanisms - tubular secretion and reabsorption - are saturable processes , they are consequently susceptible to competition between multiple substrates excreted by the kidneys. If two or more medications that are mainly renally excreted are co-administered, they may compete for renal elimination; there is a large likelihood that one agent may "out-compete" or saturate the renal excretion mechanisms before the other concomitantly administered agent(s) are excreted. As a result, the elimination of these other concurrently administered agents may be inhibited or otherwise delayed, which could lead to increases in their serum concentrations and the risk, incidence, and/or severity of adverse effects associated with the exposure to such drugs. The severity of the interaction is minor.

Question: Does Bupropion and Migalastat interact? Information: •Drug A: Bupropion •Drug B: Migalastat •Severity: MINOR •Description: Bupropion may decrease the excretion rate of Migalastat which could result in a higher serum level. •Extended Description: The renal excretion of drugs is the overall result of a combination of kidney processes that include glomerular filtration, passive diffusion, tubular secretion, and tubular reabsorption. Since two of these mechanisms - tubular secretion and reabsorption - are saturable processes , they are consequently susceptible to competition between multiple substrates excreted by the kidneys. If two or more medications that are mainly renally excreted are co-administered, they may compete for renal elimination; there is a large likelihood that one agent may "out-compete" or saturate the renal excretion mechanisms before the other concomitantly administered agent(s) are excreted. As a result, the elimination of these other concurrently administered agents may be inhibited or otherwise delayed, which could lead to increases in their serum concentrations and the risk, incidence, and/or severity of adverse effects associated with the exposure to such drugs. •Indication (Drug A): Bupropion is indicated for the treatment of major depressive disorder (MDD), seasonal affective disorder (SAD), and as an aid to smoking cessation. When used in combination with naltrexone as the marketed product ContraveⓇ, bupropion is indicated as an adjunct to a reduced-calorie diet and increased physical activity for chronic weight management in adults with an initial body mass index (BMI) of: 30 kg/m^2 or greater (obese) or 27 kg/m^2 or greater (overweight) in the presence of at least one weight-related comorbid condition (e.g., hypertension, type 2 diabetes mellitus, or dyslipidemia). Bupropion is also used off-label as a first-line treatment in patients with ADHD and comorbid bipolar disorder when used as an adjunct to mood stabilizers. •Indication (Drug B): Migalastat is approved by the FDA for the treatment of adults with a confirmed diagnosis of Fabry disease and an amenable galactosidase alpha gene (GLA) variant based on in vitro assay data. This indication is approved under accelerated approval based on a reduction in kidney interstitial capillary cell globotriaosylceramide (KIC GL-3) substrate. Continued approval for this indication may be contingent upon verification and description of clinical benefit in confirmatory trials. Migalastat is also approved by the EMA and Health Canada to treat the same disease, although it is approved for both adults and adolescents aged 16 years and older in Europe. •Pharmacodynamics (Drug A): Bupropion is chemically unrelated to tricyclic, tetracyclic, selective serotonin re-uptake inhibitors, or other known antidepressant agents. Compared to classical tricyclic antidepressants, Bupropion is a relatively weak inhibitor of the neuronal uptake of norepinephrine and dopamine. In addition, Bupropion does not inhibit monoamine oxidase. Bupropion has been found to be essentially inactive at the serotonin transporter (SERT)(IC50 >10 000 nM), however both bupropion and its primary metabolite hydroxybupropion have been found to block the function of cation-selective serotonin type 3A receptors (5-HT3ARs). Bupropion produces dose-related central nervous system (CNS) stimulant effects in animals, as evidenced by increased locomotor activity, increased rates of responding in various schedule-controlled operant behaviour tasks, and, at high doses, induction of mild stereotyped behaviour. Due to these stimulant effects and selective activity at dopamine and norepinephrine receptors, bupropion has been identified as having an abuse potential. Bupropion has a similar structure to the controlled substance Cathinone, and has been identified as having mild amphetamine-like activity, particularly when inhaled or injected. Bupropion is also known to lower the seizure threshold, making any pre-existing seizure conditions a contraindication to its use. This risk is exacerbated when bupropion is combined with other drugs or substances that lower the seizure threshold, such as cocaine, or in clinical situations that would increase the risk of a seizure such as abrupt alcohol or benzodiazepine withdrawal. As norepinephrine has been shown to have anticonvulsant properties, bupropion's inhibitory effects on NET are thought to contribute to its pro-convulsant activity. Bupropion has been shown to increase blood pressure and pose a risk for exacerbation of unmanaged or pre-existing hypertension, however, clinical trials of bupropion in smokers with CVD have not identified an increased incidence of CV events including stroke or heart attack. In clinical trials, the mean increase in systolic blood pressure associated with the use of bupropion was found to be 1.3 mmHg. •Pharmacodynamics (Drug B): In general, treatment in patients with migalastat in Phase 2 pharmacodynamic trials resulted in increases in endogenous alpha-galactosidase (alpha-Gal A) activity in white blood cells, as well as in skin and kidney for the majority of patients. In patients with amenable galactosidase alpha gene (GLA) mutations, globotriaosylceramide (GL-3) levels tended to decrease in the urine and in the kidney interstitial capillaries. In an in vitro assay (HEK-293 assay), Human Embryonic Kidney (HEK-293) cell lines were transfected with specific GLA variants (mutations) which produced mutant alpha-Gal A proteins. In the transfected cells, amenability of the GLA variants was assessed after a 5-day incubation with 10 micromol/L migalastat. A GLA variant was categorized as amenable if the resultant mutant alpha-Gal A activity (measured in the cell lysates) met two criteria: 1) it showed a relative increase of at least 20% compared to the pre-treatment alpha-Gal A activity, and 2) it showed an absolute increase of at least 3% of the wild-type (normal) alpha-Gal activity. The in vitro assay did not evaluate the trafficking of the mutant alpha-Gal A proteins into the lysosome or the dissociation of migalastat from the mutant alpha-Gal A proteins within the lysosome. Also, the in vitro assay did not test whether a GLA variant causes Fabry disease or not. •Mechanism of action (Drug A): Bupropion is a norepinephrine/dopamine-reuptake inhibitor (NDRI) that exerts its pharmacological effects by weakly inhibiting the enzymes involved in the uptake of the neurotransmitters norepinephrine and dopamine from the synaptic cleft, therefore prolonging their duration of action within the neuronal synapse and the downstream effects of these neurotransmitters. More specifically, bupropion binds to the norepinephrine transporter (NET) and the dopamine transporter (DAT). Bupropion was originally classified as an "atypical" antidepressant because it does not exert the same effects as the classical antidepressants such as Monoamine Oxidase Inhibitors (MAOIs), Tricyclic Antidepressants (TCAs), or Selective Serotonin Reuptake Inhibitors (SSRIs). While it has comparable effectiveness to typical first-line options for the treatment of depression such as SSRIs, bupropion is a unique option for the treatment of MDD as it lacks any clinically relevant serotonergic effects, typical of other mood medications, or any effects on histamine or adrenaline receptors. Lack of activity at these receptors results in a more tolerable side effect profile; bupropion is less likely to cause sexual side effects, sedation, or weight gain as compared to SSRIs or TCAs, for example. When used as an aid to smoking cessation, bupropion is thought to confer its anti-craving and anti-withdrawal effects by inhibiting dopamine reuptake, which is thought to be involved in the reward pathways associated with nicotine, and through the antagonism of the nicotinic acetylcholinergic receptor (AChR), thereby blunting the effects of nicotine. Furthermore, the stimulatory effects produced by bupropion in the central nervous system are similar to nicotine's effects, making low doses of bupropion a suitable option as a nicotine substitute. When used in combination with naltrexone in the marketed product ContraveⓇ for chronic weight management, the two components are thought to have effects on areas of the brain involved in the regulation of food intake. This includes the hypothalamus, which is involved in appetite regulation, and the mesolimbic dopamine circuit, which is involved in reward pathways. Studies have shown that the combined activity of bupropion and naltrexone increase the firing rate of hypothalamic pro-opiomelanocortin (POMC) neurons and blockade of opioid receptor-mediated POMC auto-inhibition, which are associated with a reduction in food intake and increased energy expenditure. This combination was also found to reduce food intake when injected directly into the ventral tegmental area of the mesolimbic circuit in mice, which is an area associated with the regulation of reward pathways. •Mechanism of action (Drug B): Fabry disease is a progressive X-linked lysosomal storage disorder that affects males and females. Fabry disease-causing mutations occur in the galactosidase alpha (GLA) gene and result in a deficiency of the lysosomal enzyme alpha-galactosidase A (alpha-Gal A) that is required for glycosphingolipid substrate (GL-3 and lyso-Gb3) metabolism. Reduced alpha-Gal A activity is, therefore, associated with the progressive accumulation of glycosphingolipid substrate in vulnerable organs and tissues, which ultimately leads to the morbidity and mortality associated with Fabry disease. Migalastat is a pharmacological chaperone that reversibly binds to the active site of the alpha-galactosidase A (alpha-Gal A) protein (encoded by the galactosidase alpha gene, GLA), which is deficient in Fabry disease. This binding stabilizes alpha-Gal A allowing its trafficking from the endoplasmic reticulum into the lysosome where it exerts its action. In the lysosome, at a lower pH and at a higher concentration of relevant substrates, migalastat dissociates from alpha-Gal A allowing it to break down the glycosphingolipids globotriaosylceramide (GL-3) and globotriaosylsphingosine (lyso-Gb3). Certain GLA variants (mutations) causing Fabry disease result in the production of abnormally folded and less stable forms of the alpha-Gal A protein which, however, retain enzymatic activity. Those GLA variants, referred to as amenable variants, produce alpha-Gal A proteins that may be stabilized by migalastat thereby restoring their trafficking to lysosomes and their intralysosomal activity. The GLA mutations that are amenable and not amenable to treatment with migalastat are regularly maintained and updated on online sites that are readily accessible by healthcare providers. •Absorption (Drug A): Bupropion is currently available in 3 distinct, but bioequivalent formulations: immediate release (IR), sustained-release (SR), and extended-release (XL). Immediate Release Formulation In humans, following oral administration of bupropion hydrochloride tablets, peak plasma bupropion concentrations are usually achieved within 2 hours. IR formulations provide a short duration of action and are therefore generally dosed three times per day. Sustained Release Formulation In humans, following oral administration of bupropion hydrochloride sustained-release tablets (SR), peak plasma concentration (Cmax) of bupropion is usually achieved within 3 hours. SR formulations provide a 12-hour extended release of medication and are therefore generally dosed twice per day. Extended Release Formulation Following single oral administration of bupropion hydrochloride extended-release tablets (XL) to healthy volunteers, the median time to peak plasma concentrations for bupropion was approximately 5 hours. The presence of food did not affect the peak concentration or area under the curve of bupropion. XL formulations provide a 24-hour extended release of medication and are therefore generally dosed once per day/ In a trial comparing chronic dosing with bupropion hydrochloride extended-release tablets (SR) 150 mg twice daily to bupropion immediate-release formulation 100 mg 3 times daily, the steady state Cmax for bupropion after bupropion hydrochloride sustained-release tablets (SR) administration was approximately 85% of those achieved after bupropion immediate-release formulation administration. Exposure (AUC) to bupropion was equivalent for both formulations. Bioequivalence was also demonstrated for all three major active metabolites (i.e., hydroxybupropion, threohydrobupropion and erythrohydrobupropion) for both Cmax and AUC. Thus, at steady state, bupropion hydrochloride sustained-release tablets (SR) given twice daily, and the immediate-release formulation of bupropion given 3 times daily, are essentially bioequivalent for both bupropion and the 3 quantitatively important metabolites. Furthermore, in a study comparing 14-day dosing with bupropion hydrochloride extended-release tablets (XL), 300 mg once-daily to the immediate-release formulation of bupropion at 100 mg 3 times daily, equivalence was demonstrated for peak plasma concentration and area under the curve for bupropion and the three metabolites (hydroxybupropion, threohydrobupropion, and erythrohydrobupropion). Additionally, in a study comparing 14-day dosing with bupropion hydrochloride extended-release tablets (XL) 300 mg once daily to the sustained-release formulation of bupropion at 150 mg 2 times daily, equivalence was demonstrated for peak plasma concentration and area under the curve for bupropion and the three metabolites. Bupropion hydrochloride extended-release tablets (SR) can be taken with or without food. Bupropion Cmax and AUC were increased by 11% to 35% and 16% to 19%, respectively, when bupropion hydrochloride extended-release tablets (SR) was administered with food to healthy volunteers in three trials. The food effect is not considered clinically significant. Following a single-dose administration of bupropion hydrochloride extended-release tablets (SR) in humans, Cmax of bupropion's metabolite hydroxybupropion occurs approximately 6 hours post-dose and is approximately 10 times the peak level of the parent drug at steady state. The elimination half-life of hydroxybupropion is approximately 20 (±5) hours and its AUC at steady state is about 17 times that of bupropion. The times to peak concentrations for the erythrohydrobupropion and threohydrobupropion metabolites are similar to that of the hydroxybupropion metabolite. However, their elimination half-lives are longer, 33(±10) and 37 (±13) hours, respectively, and steady-state AUCs are 1.5 and 7 times that of bupropion, respectively. •Absorption (Drug B): With absorption occurring largely in the gut, the absolute bioavailability (AUC) for a single oral 150 mg migalastat hydrochloride dose or a single 2-hour 150 mg intravenous infusion was approximately 75% and T max was approximately 3 hours. Plasma migalastat exposure (AUC 0-∞ ) and Cmax demonstrated dose-proportional increases at migalastat hydrochloride oral doses from 50 mg to 1,250 mg (doses from 0.5 to 8.3-fold of the approved recommended dosage). Migalastat administered with a high-fat meal (850 calories; 56% from fat), or 1 hour before a high-fat or light meal (507 calories; 30% from fat), or 1 hour after a light meal, resulted in significant reductions of 37% to 42% in mean total migalastat exposure (AUC 0-∞ ) and reductions of 15% to 39% in mean peak migalastat exposure (Cmax) compared with the fasting state. •Volume of distribution (Drug A): No volume of distribution available •Volume of distribution (Drug B): In healthy volunteers, the volume of distribution (Vz/F) of migalastat following ascending single oral doses (25-675 mg migalastat HCl) ranged from 77 to 133 L, indicating it is well distributed into tissues and greater than total body water (42 liters). •Protein binding (Drug A): In vitro tests show that bupropion is 84% bound to human plasma proteins at concentrations up to 200 mcg per mL. The extent of protein binding of the hydroxybupropion metabolite is similar to that for bupropion, whereas the extent of protein binding of the threohydrobupropion metabolite is about half that seen with bupropion. •Protein binding (Drug B): There was no detectable plasma protein binding following administration of [14C]-migalastat hydrochloride in the concentration range between 1 and 100 µM. •Metabolism (Drug A): Bupropion is extensively metabolized in humans. Three metabolites are active: hydroxybupropion, which is formed via hydroxylation of the tert-butyl group of bupropion, and the amino-alcohol isomers, threohydrobupropion and erythrohydrobupropion, which are formed via reduction of the carbonyl group. In vitro findings suggest that CYP2B6 is the principal isoenzyme involved in the formation of hydroxybupropion, while cytochrome P450 enzymes are not involved in the formation of threohydrobupropion. Hydroxybupropion has been shown to have the same affinity as bupropion for the norepinephrine transporter (NET) but approximately 50% of its antidepressant activity despite reaching concentrations of ~10-fold higher than that of the parent drug. Oxidation of the bupropion side chain results in the formation of a glycine conjugate of meta-chlorobenzoic acid, which is then excreted as the major urinary metabolite. The potency and toxicity of the metabolites relative to bupropion have not been fully characterized. However, it has been demonstrated in an antidepressant screening test in mice that hydroxybupropion is one-half as potent as bupropion, while threohydrobupropion and erythrohydrobupropion are 5-fold less potent than bupropion. This may be of clinical importance because the plasma concentrations of the metabolites are as high as or higher than those of bupropion. Bupropion and its metabolites exhibit linear kinetics following chronic administration of 300 to 450 mg per day. •Metabolism (Drug B): Based upon in vivo data, migalastat is a substrate for uridine diphosphate glucuronosyltransferase (otherwise known as UGT or UDPGT), being a minor elimination pathway. •Route of elimination (Drug A): Bupropion is extensively metabolized in humans. Oxidation of the bupropion side chain results in the formation of a glycine conjugate of metachlorobenzoic acid, which is then excreted as the major urinary metabolite. Following oral administration of 200 mg of 14C-bupropion in humans, 87% and 10% of the radioactive dose were recovered in the urine and feces, respectively. However, the fraction of the oral dose of bupropion excreted unchanged was only 0.5%, a finding consistent with the extensive metabolism of bupropion. •Route of elimination (Drug B): In a mass balance study in healthy male subjects, following oral administration of 123 mg [14C]-migalastat, approximately 77% of the total radiolabeled dose was recovered in urine and 20% of the total radiolabeled dose was recovered in feces with an overall total recovery of 98% within 96 hours post-dose. In urine, unchanged migalastat accounted for 80% of the radioactivity, which equates to 62% of the administered dose. In feces, unchanged migalastat was the only drug-related component. In plasma, unchanged migalastat accounted for approximately 77% of the plasma radioactivity, and three dehydrogenated O-glucuronide conjugated metabolites, M1 to M3, together accounted for approximately 13% of the plasma radioactivity, none of which comprised more than 6% of the radiolabeled dose. Approximately 9% of the total radioactivity in plasma was unassigned. •Half-life (Drug A): 24 hours •Half-life (Drug B): The mean elimination half-life (t1/2) of migalastat ranges from approximately 3 to 5 hours for a single oral dose of 150 mg. For the dose of 123 mg, the mean elimination half-life was estimated to be 4 hours. •Clearance (Drug A): No clearance available •Clearance (Drug B): Following ascending single oral doses (25-675 mg migalastat hydrochloride), no trends were found for clearance (CL/F). At the 150 mg dose, CL/F was approximately 11 to 14 L/hr, while at 123 mg, the apparent clearance was calculated to be 12.5 L/hr. •Toxicity (Drug A): Symptoms of overdose include seizures, hallucinations, loss of consciousness, tachycardia, and cardiac arrest. •Toxicity (Drug B): The most common adverse reactions reported with migalastat (≥ 10%) during the 6-month placebo-controlled, double-blind phase of its Study 1 clinical studies were headache, nasopharyngitis, urinary tract infection, nausea, and pyrexia. In case of overdose, general medical care is recommended. Headache and dizziness were the most common adverse reactions reported at doses of migalastat of up to 1250 mg and 2000 mg, respectively. •Brand Names (Drug A): Aplenzin, Auvelity, Budeprion, Contrave, Forfivo, Wellbutrin, Zyban •Brand Names (Drug B): Galafold •Synonyms (Drug A): No synonyms listed •Synonyms (Drug B): No synonyms listed •Summary (Drug A): Bupropion is a norepinephrine and dopamine reuptake inhibitor used in the treatment of major depressive disorder (MDD), seasonal affective disorder (SAD), and as an aid to smoking cessation. •Summary (Drug B): Migalastat is an alpha-galactosidase A chaperone used for the treatment of Fabry disease in patients with an amenable galactosidase alpha gene (GLA) variant. Output: The renal excretion of drugs is the overall result of a combination of kidney processes that include glomerular filtration, passive diffusion, tubular secretion, and tubular reabsorption. Since two of these mechanisms - tubular secretion and reabsorption - are saturable processes , they are consequently susceptible to competition between multiple substrates excreted by the kidneys. If two or more medications that are mainly renally excreted are co-administered, they may compete for renal elimination; there is a large likelihood that one agent may "out-compete" or saturate the renal excretion mechanisms before the other concomitantly administered agent(s) are excreted. As a result, the elimination of these other concurrently administered agents may be inhibited or otherwise delayed, which could lead to increases in their serum concentrations and the risk, incidence, and/or severity of adverse effects associated with the exposure to such drugs. The severity of the interaction is minor.

Does Bupropion and Milnacipran interact?

•Drug A: Bupropion •Drug B: Milnacipran •Severity: MODERATE •Description: The risk or severity of adverse effects can be increased when Bupropion is combined with Milnacipran. •Extended Description: Depending on the central nervous system depressant, some drugs may interact with selective serotonin reuptake inhibitors, causing a variety of CNS effects. Effects can range from mild sedation to severe respiratory depression and may be caused by a variety of mechanisms, either pharmacodynamically or pharmacokinetically. The severity of drug interaction effects differs between different combinations of CNS depressants and SSRIs, depending on factors such as affinity to CYP450 enzymes, drug half-lives, and mechanism of action.. However, due to their specific mechanism of action and extensive liver metabolism, SSRIs drug interactions tend to be mediated through liver enzymes more often. Additionally, when combined with other CNS depressants, SSRIs are not equivalent in their potential to induce drug-drug interaction. •Indication (Drug A): Bupropion is indicated for the treatment of major depressive disorder (MDD), seasonal affective disorder (SAD), and as an aid to smoking cessation. When used in combination with naltrexone as the marketed product ContraveⓇ, bupropion is indicated as an adjunct to a reduced-calorie diet and increased physical activity for chronic weight management in adults with an initial body mass index (BMI) of: 30 kg/m^2 or greater (obese) or 27 kg/m^2 or greater (overweight) in the presence of at least one weight-related comorbid condition (e.g., hypertension, type 2 diabetes mellitus, or dyslipidemia). Bupropion is also used off-label as a first-line treatment in patients with ADHD and comorbid bipolar disorder when used as an adjunct to mood stabilizers. •Indication (Drug B): Milnacipran is a selective serotonin and norepinephrine reuptake inhibitor (SNRI) indicated for the management of fibromyalgia in patients that are 18 years old or above. While milnacipran may be used for the treatment of major depressive disorder (MDD), it is only recommended in adult patients who are 18 years old or above due to an increased risk for suicidal ideation, thinking, and behavior in children, adolescents, and young adults taking antidepressants for major depressive disorder (MDD) and other psychiatric disorders. Some regional prescribing information notes that the use of the medication is specifically for the short-term symptomatic relief of MDD. Nevertheless, it is important to note that the regulatory approval of and/or indications listed here for milnacipran may or may not exist and/or vary greatly between regions and nations. •Pharmacodynamics (Drug A): Bupropion is chemically unrelated to tricyclic, tetracyclic, selective serotonin re-uptake inhibitors, or other known antidepressant agents. Compared to classical tricyclic antidepressants, Bupropion is a relatively weak inhibitor of the neuronal uptake of norepinephrine and dopamine. In addition, Bupropion does not inhibit monoamine oxidase. Bupropion has been found to be essentially inactive at the serotonin transporter (SERT)(IC50 >10 000 nM), however both bupropion and its primary metabolite hydroxybupropion have been found to block the function of cation-selective serotonin type 3A receptors (5-HT3ARs). Bupropion produces dose-related central nervous system (CNS) stimulant effects in animals, as evidenced by increased locomotor activity, increased rates of responding in various schedule-controlled operant behaviour tasks, and, at high doses, induction of mild stereotyped behaviour. Due to these stimulant effects and selective activity at dopamine and norepinephrine receptors, bupropion has been identified as having an abuse potential. Bupropion has a similar structure to the controlled substance Cathinone, and has been identified as having mild amphetamine-like activity, particularly when inhaled or injected. Bupropion is also known to lower the seizure threshold, making any pre-existing seizure conditions a contraindication to its use. This risk is exacerbated when bupropion is combined with other drugs or substances that lower the seizure threshold, such as cocaine, or in clinical situations that would increase the risk of a seizure such as abrupt alcohol or benzodiazepine withdrawal. As norepinephrine has been shown to have anticonvulsant properties, bupropion's inhibitory effects on NET are thought to contribute to its pro-convulsant activity. Bupropion has been shown to increase blood pressure and pose a risk for exacerbation of unmanaged or pre-existing hypertension, however, clinical trials of bupropion in smokers with CVD have not identified an increased incidence of CV events including stroke or heart attack. In clinical trials, the mean increase in systolic blood pressure associated with the use of bupropion was found to be 1.3 mmHg. •Pharmacodynamics (Drug B): When utilized to treat fibromyalgia, the effect of milnacipran on the QTcF interval in patients was measured in a double-blind placebo-and positive-controlled parallel study in 88 healthy subjects using three to six times the recommended therapeutic dose for fibromyalgia at 600 mg/day. After baseline and placebo adjustment, the maximum mean QTcF change was 8 ms - an increase that is generally not considered to be clinically significant. Conversely, when used for treating major depressive disorder (MDD), non-clinical studies have shown that levomilnacipran binds with high affinity to the norepinephrine (NE) and serotonin (5-HT) transporters (Ki = 71-91 nM and 11 nM respectively at human transporters). Levomilnacipran inhibits the uptake of both NE and 5-HT in vitro and in vivo; preferentially inhibiting reuptake of NE over 5-HT by approximately 2-fold. Levomilnacipran does not directly affect the uptake of dopamine or other neurotransmitters. Levomilnacipran has no significant affinity for serotonergic (5-HT1-7), α- and β-adrenergic, muscarinic (M1-5), histamine (H1-4), dopamine (D1-5), opiate, benzodiazepine, and γ-aminobutyric acid (GABA) receptors in vitro. Levomilnacipran has no significant affinity for Ca++, K+, Na+, and Cl– channels and does not inhibit the activity of human monoamine oxidases (MAO-A and MAO-B) or acetylcholinesterase. Moreover, in ECG studies with levomilnacipran used to treat MDD, although no clinically significant changes in QTcF interval (QTcF=QT/RR0.33) were noted, it appears that the agent can cause increases in heart rate and blood pressure. In particular, it appears that the maximum therapeutic dose of levomilnacipran at 120 mg/day is capable of causing a maximum mean difference in heart rate from placebo of 20.2 bpm and a mean difference in systolic and diastolic blood pressure from placebo ranging from 3.8 to 7.2 mmHg and 6.1 to 8.1 mmHg, respectively. Alternatively, a supratherapeutic dose of 300 mg/day is capable of causing a maximum mean difference in heart rate from placebo of 22.1 bpm and a mean difference in systolic and diastolic blood pressure from placebo ranging from 5.4 to 7.9 mmHg and 7.9 to 10.6 mmHg, respectively. •Mechanism of action (Drug A): Bupropion is a norepinephrine/dopamine-reuptake inhibitor (NDRI) that exerts its pharmacological effects by weakly inhibiting the enzymes involved in the uptake of the neurotransmitters norepinephrine and dopamine from the synaptic cleft, therefore prolonging their duration of action within the neuronal synapse and the downstream effects of these neurotransmitters. More specifically, bupropion binds to the norepinephrine transporter (NET) and the dopamine transporter (DAT). Bupropion was originally classified as an "atypical" antidepressant because it does not exert the same effects as the classical antidepressants such as Monoamine Oxidase Inhibitors (MAOIs), Tricyclic Antidepressants (TCAs), or Selective Serotonin Reuptake Inhibitors (SSRIs). While it has comparable effectiveness to typical first-line options for the treatment of depression such as SSRIs, bupropion is a unique option for the treatment of MDD as it lacks any clinically relevant serotonergic effects, typical of other mood medications, or any effects on histamine or adrenaline receptors. Lack of activity at these receptors results in a more tolerable side effect profile; bupropion is less likely to cause sexual side effects, sedation, or weight gain as compared to SSRIs or TCAs, for example. When used as an aid to smoking cessation, bupropion is thought to confer its anti-craving and anti-withdrawal effects by inhibiting dopamine reuptake, which is thought to be involved in the reward pathways associated with nicotine, and through the antagonism of the nicotinic acetylcholinergic receptor (AChR), thereby blunting the effects of nicotine. Furthermore, the stimulatory effects produced by bupropion in the central nervous system are similar to nicotine's effects, making low doses of bupropion a suitable option as a nicotine substitute. When used in combination with naltrexone in the marketed product ContraveⓇ for chronic weight management, the two components are thought to have effects on areas of the brain involved in the regulation of food intake. This includes the hypothalamus, which is involved in appetite regulation, and the mesolimbic dopamine circuit, which is involved in reward pathways. Studies have shown that the combined activity of bupropion and naltrexone increase the firing rate of hypothalamic pro-opiomelanocortin (POMC) neurons and blockade of opioid receptor-mediated POMC auto-inhibition, which are associated with a reduction in food intake and increased energy expenditure. This combination was also found to reduce food intake when injected directly into the ventral tegmental area of the mesolimbic circuit in mice, which is an area associated with the regulation of reward pathways. •Mechanism of action (Drug B): The dual ability for milnacipran to inhibit the reuptake of both serotonin (5HT) and norepinephrine (NE) facilitates its treatment of both fibromyalgia and major depressive disorder (MDD). In particular, it is generally believed that 5HT and NE participate in the modulation of endogenous analgesic mechanisms by way of the descending inhibitory pain pathways in the brain and spinal cord. Although the specific mechanism of action remains unclear, some studies have proposed that low levels of 5HT may be associated with increased sensitivity to pain - a condition that could subsequently be improved by milnacipran's capacity to enhance the presence of 5HT by inhibiting its reuptake via serotonin transporters at synaptic clefts. Furthermore, in the CNS it is also generally believed that NE released from descending pathways can mitigate pain sensations via eliciting inhibitory effects on alpha-2A-adrenoceptors on central terminals of primary afferent nociceptors, by direct alpha-2-adrenergic action on pain-relay neurons, and by alpha-1-adrenoceptor-mediated activation of inhibitory interneurons. Such NE pain mitigation is consequently also enhanced by milnacipran's ability to enhance the presence of NE by inhibiting its reuptake via norepinephrine transporters at synaptic clefts. Concurrently, milnacipran's capacity to inhibit the reuptake of both 5HT and NE also facilitates its treatment of MDD. Given the monoamine hypothesis' assertion that decreased 5HT can be associated with anxiety, obsessions, compulsions, and decreased NE can result in lowered alertness, energy, attention, and general interest in life, it is proposed that milnacipran's basic activities as a serotonin and norepinephrine reuptake inhibitor could assist in treating such symptoms of MDD by increasing the presence of both 5HT and NE in the body by inhibiting their reuptake. •Absorption (Drug A): Bupropion is currently available in 3 distinct, but bioequivalent formulations: immediate release (IR), sustained-release (SR), and extended-release (XL). Immediate Release Formulation In humans, following oral administration of bupropion hydrochloride tablets, peak plasma bupropion concentrations are usually achieved within 2 hours. IR formulations provide a short duration of action and are therefore generally dosed three times per day. Sustained Release Formulation In humans, following oral administration of bupropion hydrochloride sustained-release tablets (SR), peak plasma concentration (Cmax) of bupropion is usually achieved within 3 hours. SR formulations provide a 12-hour extended release of medication and are therefore generally dosed twice per day. Extended Release Formulation Following single oral administration of bupropion hydrochloride extended-release tablets (XL) to healthy volunteers, the median time to peak plasma concentrations for bupropion was approximately 5 hours. The presence of food did not affect the peak concentration or area under the curve of bupropion. XL formulations provide a 24-hour extended release of medication and are therefore generally dosed once per day/ In a trial comparing chronic dosing with bupropion hydrochloride extended-release tablets (SR) 150 mg twice daily to bupropion immediate-release formulation 100 mg 3 times daily, the steady state Cmax for bupropion after bupropion hydrochloride sustained-release tablets (SR) administration was approximately 85% of those achieved after bupropion immediate-release formulation administration. Exposure (AUC) to bupropion was equivalent for both formulations. Bioequivalence was also demonstrated for all three major active metabolites (i.e., hydroxybupropion, threohydrobupropion and erythrohydrobupropion) for both Cmax and AUC. Thus, at steady state, bupropion hydrochloride sustained-release tablets (SR) given twice daily, and the immediate-release formulation of bupropion given 3 times daily, are essentially bioequivalent for both bupropion and the 3 quantitatively important metabolites. Furthermore, in a study comparing 14-day dosing with bupropion hydrochloride extended-release tablets (XL), 300 mg once-daily to the immediate-release formulation of bupropion at 100 mg 3 times daily, equivalence was demonstrated for peak plasma concentration and area under the curve for bupropion and the three metabolites (hydroxybupropion, threohydrobupropion, and erythrohydrobupropion). Additionally, in a study comparing 14-day dosing with bupropion hydrochloride extended-release tablets (XL) 300 mg once daily to the sustained-release formulation of bupropion at 150 mg 2 times daily, equivalence was demonstrated for peak plasma concentration and area under the curve for bupropion and the three metabolites. Bupropion hydrochloride extended-release tablets (SR) can be taken with or without food. Bupropion Cmax and AUC were increased by 11% to 35% and 16% to 19%, respectively, when bupropion hydrochloride extended-release tablets (SR) was administered with food to healthy volunteers in three trials. The food effect is not considered clinically significant. Following a single-dose administration of bupropion hydrochloride extended-release tablets (SR) in humans, Cmax of bupropion's metabolite hydroxybupropion occurs approximately 6 hours post-dose and is approximately 10 times the peak level of the parent drug at steady state. The elimination half-life of hydroxybupropion is approximately 20 (±5) hours and its AUC at steady state is about 17 times that of bupropion. The times to peak concentrations for the erythrohydrobupropion and threohydrobupropion metabolites are similar to that of the hydroxybupropion metabolite. However, their elimination half-lives are longer, 33(±10) and 37 (±13) hours, respectively, and steady-state AUCs are 1.5 and 7 times that of bupropion, respectively. •Absorption (Drug B): Racemic milnacipram demonstrates an absolute bioavailability of about 85-90% following oral administration. Maximum concentrations of the racemic agent are reached within 2-4 hours after oral dosing, and steady-state levels are obtained by 36-48 hours. Conversely, the relative bioavailability of levomilnacipram has been documented as 92%. The median time to peak concentration Tmax for levomilnacipram is about 6-8 hours after oral administration. After daily dosing of levomilnacipram 120 mg, the mean Cmax value is 341 ng/mL, and the mean steady-state AUC value is 5196 ng.h/mL. In general, the administration of either racemic milnacipram or levomilnacipram with food does not affect the medication's oral bioavailability. •Volume of distribution (Drug A): No volume of distribution available •Volume of distribution (Drug B): The mean volume of distribution recorded for racemic milnacipran following a single intravenous dose to healthy subjects was approximately 400 L. Alternatively, levomilnacipran is widely distributed with an apparent volume of distribution of 387-473 L. •Protein binding (Drug A): In vitro tests show that bupropion is 84% bound to human plasma proteins at concentrations up to 200 mcg per mL. The extent of protein binding of the hydroxybupropion metabolite is similar to that for bupropion, whereas the extent of protein binding of the threohydrobupropion metabolite is about half that seen with bupropion. •Protein binding (Drug B): The protein binding determined for racemic milnacipran is 13%. Conversely, the plasma protein binding documented for levomilnacipran is 22% over a concentration range of 10 to 1000 ng/mL. •Metabolism (Drug A): Bupropion is extensively metabolized in humans. Three metabolites are active: hydroxybupropion, which is formed via hydroxylation of the tert-butyl group of bupropion, and the amino-alcohol isomers, threohydrobupropion and erythrohydrobupropion, which are formed via reduction of the carbonyl group. In vitro findings suggest that CYP2B6 is the principal isoenzyme involved in the formation of hydroxybupropion, while cytochrome P450 enzymes are not involved in the formation of threohydrobupropion. Hydroxybupropion has been shown to have the same affinity as bupropion for the norepinephrine transporter (NET) but approximately 50% of its antidepressant activity despite reaching concentrations of ~10-fold higher than that of the parent drug. Oxidation of the bupropion side chain results in the formation of a glycine conjugate of meta-chlorobenzoic acid, which is then excreted as the major urinary metabolite. The potency and toxicity of the metabolites relative to bupropion have not been fully characterized. However, it has been demonstrated in an antidepressant screening test in mice that hydroxybupropion is one-half as potent as bupropion, while threohydrobupropion and erythrohydrobupropion are 5-fold less potent than bupropion. This may be of clinical importance because the plasma concentrations of the metabolites are as high as or higher than those of bupropion. Bupropion and its metabolites exhibit linear kinetics following chronic administration of 300 to 450 mg per day. •Metabolism (Drug B): It has been determined that levomilnacipran undergoes desethylation and hydroxylation to generate desethyl levomilnacipran and p-hydroxy-levomilnacipran, respectively. Both oxidative metabolites undergo further conjugation with glucuronide to form the conjugate milnacipran carbamoyl-O-glucuronide. The desethylation is catalyzed primarily by CYP3A4 with minor contribution by CYP2C8, 2C19, 2D6, and 2J2. Additionally, it is the general understanding that there is no interconversion between the enantiomers of milnacipran in the body. •Route of elimination (Drug A): Bupropion is extensively metabolized in humans. Oxidation of the bupropion side chain results in the formation of a glycine conjugate of metachlorobenzoic acid, which is then excreted as the major urinary metabolite. Following oral administration of 200 mg of 14C-bupropion in humans, 87% and 10% of the radioactive dose were recovered in the urine and feces, respectively. However, the fraction of the oral dose of bupropion excreted unchanged was only 0.5%, a finding consistent with the extensive metabolism of bupropion. •Route of elimination (Drug B): Levomilnacipran and its metabolites are eliminated primarily by renal excretion. Following oral administration of 14C-levomilnacipran solution, approximately 58% of the dose is excreted in urine as unchanged levomilnacipran. N-desethyl levomilnacipran is the major metabolite excreted in the urine and accounted for approximately 18% of the dose. Other identifiable metabolites excreted in the urine are levomilnacipran glucuronide (4%), desethyl levomilnacipran glucuronide (3%), p-hydroxy levomilnacipran glucuronide (1%), and p-hydroxy levomilnacipran (1%). •Half-life (Drug A): 24 hours •Half-life (Drug B): The terminal elimination half-life documented for racemic milnacipran is approximately 6-8 hours, where d-milnacipran has a longer elimination half-life of 8-10 hours compared to that of the l-enantionmer at 4-6 hours. Alternatively, the terminal elimination half-life determined specifically for levomilnacipran formulations is about 12 hours. •Clearance (Drug A): No clearance available •Clearance (Drug B): The total plasma clearance determined for milnacipran is approximately 40 L/h. •Toxicity (Drug A): Symptoms of overdose include seizures, hallucinations, loss of consciousness, tachycardia, and cardiac arrest. •Toxicity (Drug B): There is limited clinical experience with milnacipran overdose in humans. In clinical trials, cases of acute ingestions up to 1000 mg daily were reported with none being fatal. In postmarketing experience, fatal outcomes have been reported for acute overdoses primarily involving multiple drugs but also with milnacipran only. The most common signs and symptoms of overdose included increased blood pressure, cardio-respiratory arrest, changes in the level of consciousness (ranging from somnolence to coma), confusional state, dizziness, and increased hepatic enzymes. There are no adequate and well-controlled studies in pregnant women. In fact, milnacipram should be used during pregnancy only if the potential benefit justifies the potential risk to the fetus. Neonates exposed to SSRIs or SNRIs, late in the third trimester have developed complications requiring prolonged hospitalization, respiratory support, and tube feeding. Such complications can arise immediately upon delivery. Reported clinical findings have included respiratory distress, cyanosis, apnea, seizures, temperature instability, feeding difficulty, vomiting, hypoglycemia, hypotonia, hypertonia, hyperreflexia, tremor, jitteriness, irritability, and constant crying. These features are consistent with either a direct toxic effect of SNRI class drugs like milnacipran or, possibly, a drug discontinuation syndrome. It should be noted that, in some cases, the clinical picture is consistent with serotonin syndrome. The effect of milnacipran on labor and delivery in humans is unknown. Milnacipran should be used during labor and delivery only if the potential benefits outweigh the potential risks. There are no adequate and well-controlled studies in nursing mothers. It is not known if milnacipran is excreted in human milk. Studies have shown that levomilnacipran is excreted into the milk of lactating rats. Subsequently, possible excretion into human milk possesses the potential for serious adverse reactions in nursing infants. As a consequence, breastfeeding by women treated with levomilnacipran should be considered only if the potential benefits outweigh the potential risks to the child. Milnacipran is not indicated for use in children under 18 years of age due to concerns over the potential for agitation-type emotional and behavioral changes, as well as suicidal ideation and/or behavior. SNRIs like milnacipran have been associated with cases of clinically significant hyponatremia in elderly patients, who may be at greater risk for this adverse event. Levomilnacipran was not mutagenic when evaluated in vitro in a bacterial mutagenicity study (Ames test) and not genotoxic in a mouse lymphoma study. It was not clastogenic in an in vivo micronucleus assay in rats. The potential effects of levomilnacipran on gonadal function, mating behavior, reproductive performance and early pregnancy were evaluated in rats at oral doses of 0, 10, 30, or 100 mg/kg/day. The NOAEL was 100 mg/kg/day based on reductions in body weight gain and food consumption. There were no levomilnacipran effects on male and female fertility parameters. In the rat and rabbit embryo/fetal development studies, decreases in maternal body weight gain and food consumption were noted. In the fetuses, increases in the incidence of ossification anomalies were noted but were of no toxicological significance. In both species, the NOAEL was determined to be 100 mg/kg/day, a dose which represents a rat or rabbit animal-to-human exposure margin of 9-fold and 4-fold, respectively relative to the human exposure from 120 mg/day of levomilnacipran. Material safety data for milnacipran has documented the LD50 oral value in the rat model as being 213 mg/kg. •Brand Names (Drug A): Aplenzin, Auvelity, Budeprion, Contrave, Forfivo, Wellbutrin, Zyban •Brand Names (Drug B): Savella •Synonyms (Drug A): No synonyms listed •Synonyms (Drug B): Midalcipran Milnacipran Milnacipranum •Summary (Drug A): Bupropion is a norepinephrine and dopamine reuptake inhibitor used in the treatment of major depressive disorder (MDD), seasonal affective disorder (SAD), and as an aid to smoking cessation. •Summary (Drug B): Milnacipran is a selective serotonin and norepinephrine reuptake inhibitor (SNRI) used for the treatment of fibromyalgia and a short-term treatment of major depressive disorder.

Depending on the central nervous system depressant, some drugs may interact with selective serotonin reuptake inhibitors, causing a variety of CNS effects. Effects can range from mild sedation to severe respiratory depression and may be caused by a variety of mechanisms, either pharmacodynamically or pharmacokinetically. The severity of drug interaction effects differs between different combinations of CNS depressants and SSRIs, depending on factors such as affinity to CYP450 enzymes, drug half-lives, and mechanism of action.. However, due to their specific mechanism of action and extensive liver metabolism, SSRIs drug interactions tend to be mediated through liver enzymes more often. Additionally, when combined with other CNS depressants, SSRIs are not equivalent in their potential to induce drug-drug interaction. The severity of the interaction is moderate.

Question: Does Bupropion and Milnacipran interact? Information: •Drug A: Bupropion •Drug B: Milnacipran •Severity: MODERATE •Description: The risk or severity of adverse effects can be increased when Bupropion is combined with Milnacipran. •Extended Description: Depending on the central nervous system depressant, some drugs may interact with selective serotonin reuptake inhibitors, causing a variety of CNS effects. Effects can range from mild sedation to severe respiratory depression and may be caused by a variety of mechanisms, either pharmacodynamically or pharmacokinetically. The severity of drug interaction effects differs between different combinations of CNS depressants and SSRIs, depending on factors such as affinity to CYP450 enzymes, drug half-lives, and mechanism of action.. However, due to their specific mechanism of action and extensive liver metabolism, SSRIs drug interactions tend to be mediated through liver enzymes more often. Additionally, when combined with other CNS depressants, SSRIs are not equivalent in their potential to induce drug-drug interaction. •Indication (Drug A): Bupropion is indicated for the treatment of major depressive disorder (MDD), seasonal affective disorder (SAD), and as an aid to smoking cessation. When used in combination with naltrexone as the marketed product ContraveⓇ, bupropion is indicated as an adjunct to a reduced-calorie diet and increased physical activity for chronic weight management in adults with an initial body mass index (BMI) of: 30 kg/m^2 or greater (obese) or 27 kg/m^2 or greater (overweight) in the presence of at least one weight-related comorbid condition (e.g., hypertension, type 2 diabetes mellitus, or dyslipidemia). Bupropion is also used off-label as a first-line treatment in patients with ADHD and comorbid bipolar disorder when used as an adjunct to mood stabilizers. •Indication (Drug B): Milnacipran is a selective serotonin and norepinephrine reuptake inhibitor (SNRI) indicated for the management of fibromyalgia in patients that are 18 years old or above. While milnacipran may be used for the treatment of major depressive disorder (MDD), it is only recommended in adult patients who are 18 years old or above due to an increased risk for suicidal ideation, thinking, and behavior in children, adolescents, and young adults taking antidepressants for major depressive disorder (MDD) and other psychiatric disorders. Some regional prescribing information notes that the use of the medication is specifically for the short-term symptomatic relief of MDD. Nevertheless, it is important to note that the regulatory approval of and/or indications listed here for milnacipran may or may not exist and/or vary greatly between regions and nations. •Pharmacodynamics (Drug A): Bupropion is chemically unrelated to tricyclic, tetracyclic, selective serotonin re-uptake inhibitors, or other known antidepressant agents. Compared to classical tricyclic antidepressants, Bupropion is a relatively weak inhibitor of the neuronal uptake of norepinephrine and dopamine. In addition, Bupropion does not inhibit monoamine oxidase. Bupropion has been found to be essentially inactive at the serotonin transporter (SERT)(IC50 >10 000 nM), however both bupropion and its primary metabolite hydroxybupropion have been found to block the function of cation-selective serotonin type 3A receptors (5-HT3ARs). Bupropion produces dose-related central nervous system (CNS) stimulant effects in animals, as evidenced by increased locomotor activity, increased rates of responding in various schedule-controlled operant behaviour tasks, and, at high doses, induction of mild stereotyped behaviour. Due to these stimulant effects and selective activity at dopamine and norepinephrine receptors, bupropion has been identified as having an abuse potential. Bupropion has a similar structure to the controlled substance Cathinone, and has been identified as having mild amphetamine-like activity, particularly when inhaled or injected. Bupropion is also known to lower the seizure threshold, making any pre-existing seizure conditions a contraindication to its use. This risk is exacerbated when bupropion is combined with other drugs or substances that lower the seizure threshold, such as cocaine, or in clinical situations that would increase the risk of a seizure such as abrupt alcohol or benzodiazepine withdrawal. As norepinephrine has been shown to have anticonvulsant properties, bupropion's inhibitory effects on NET are thought to contribute to its pro-convulsant activity. Bupropion has been shown to increase blood pressure and pose a risk for exacerbation of unmanaged or pre-existing hypertension, however, clinical trials of bupropion in smokers with CVD have not identified an increased incidence of CV events including stroke or heart attack. In clinical trials, the mean increase in systolic blood pressure associated with the use of bupropion was found to be 1.3 mmHg. •Pharmacodynamics (Drug B): When utilized to treat fibromyalgia, the effect of milnacipran on the QTcF interval in patients was measured in a double-blind placebo-and positive-controlled parallel study in 88 healthy subjects using three to six times the recommended therapeutic dose for fibromyalgia at 600 mg/day. After baseline and placebo adjustment, the maximum mean QTcF change was 8 ms - an increase that is generally not considered to be clinically significant. Conversely, when used for treating major depressive disorder (MDD), non-clinical studies have shown that levomilnacipran binds with high affinity to the norepinephrine (NE) and serotonin (5-HT) transporters (Ki = 71-91 nM and 11 nM respectively at human transporters). Levomilnacipran inhibits the uptake of both NE and 5-HT in vitro and in vivo; preferentially inhibiting reuptake of NE over 5-HT by approximately 2-fold. Levomilnacipran does not directly affect the uptake of dopamine or other neurotransmitters. Levomilnacipran has no significant affinity for serotonergic (5-HT1-7), α- and β-adrenergic, muscarinic (M1-5), histamine (H1-4), dopamine (D1-5), opiate, benzodiazepine, and γ-aminobutyric acid (GABA) receptors in vitro. Levomilnacipran has no significant affinity for Ca++, K+, Na+, and Cl– channels and does not inhibit the activity of human monoamine oxidases (MAO-A and MAO-B) or acetylcholinesterase. Moreover, in ECG studies with levomilnacipran used to treat MDD, although no clinically significant changes in QTcF interval (QTcF=QT/RR0.33) were noted, it appears that the agent can cause increases in heart rate and blood pressure. In particular, it appears that the maximum therapeutic dose of levomilnacipran at 120 mg/day is capable of causing a maximum mean difference in heart rate from placebo of 20.2 bpm and a mean difference in systolic and diastolic blood pressure from placebo ranging from 3.8 to 7.2 mmHg and 6.1 to 8.1 mmHg, respectively. Alternatively, a supratherapeutic dose of 300 mg/day is capable of causing a maximum mean difference in heart rate from placebo of 22.1 bpm and a mean difference in systolic and diastolic blood pressure from placebo ranging from 5.4 to 7.9 mmHg and 7.9 to 10.6 mmHg, respectively. •Mechanism of action (Drug A): Bupropion is a norepinephrine/dopamine-reuptake inhibitor (NDRI) that exerts its pharmacological effects by weakly inhibiting the enzymes involved in the uptake of the neurotransmitters norepinephrine and dopamine from the synaptic cleft, therefore prolonging their duration of action within the neuronal synapse and the downstream effects of these neurotransmitters. More specifically, bupropion binds to the norepinephrine transporter (NET) and the dopamine transporter (DAT). Bupropion was originally classified as an "atypical" antidepressant because it does not exert the same effects as the classical antidepressants such as Monoamine Oxidase Inhibitors (MAOIs), Tricyclic Antidepressants (TCAs), or Selective Serotonin Reuptake Inhibitors (SSRIs). While it has comparable effectiveness to typical first-line options for the treatment of depression such as SSRIs, bupropion is a unique option for the treatment of MDD as it lacks any clinically relevant serotonergic effects, typical of other mood medications, or any effects on histamine or adrenaline receptors. Lack of activity at these receptors results in a more tolerable side effect profile; bupropion is less likely to cause sexual side effects, sedation, or weight gain as compared to SSRIs or TCAs, for example. When used as an aid to smoking cessation, bupropion is thought to confer its anti-craving and anti-withdrawal effects by inhibiting dopamine reuptake, which is thought to be involved in the reward pathways associated with nicotine, and through the antagonism of the nicotinic acetylcholinergic receptor (AChR), thereby blunting the effects of nicotine. Furthermore, the stimulatory effects produced by bupropion in the central nervous system are similar to nicotine's effects, making low doses of bupropion a suitable option as a nicotine substitute. When used in combination with naltrexone in the marketed product ContraveⓇ for chronic weight management, the two components are thought to have effects on areas of the brain involved in the regulation of food intake. This includes the hypothalamus, which is involved in appetite regulation, and the mesolimbic dopamine circuit, which is involved in reward pathways. Studies have shown that the combined activity of bupropion and naltrexone increase the firing rate of hypothalamic pro-opiomelanocortin (POMC) neurons and blockade of opioid receptor-mediated POMC auto-inhibition, which are associated with a reduction in food intake and increased energy expenditure. This combination was also found to reduce food intake when injected directly into the ventral tegmental area of the mesolimbic circuit in mice, which is an area associated with the regulation of reward pathways. •Mechanism of action (Drug B): The dual ability for milnacipran to inhibit the reuptake of both serotonin (5HT) and norepinephrine (NE) facilitates its treatment of both fibromyalgia and major depressive disorder (MDD). In particular, it is generally believed that 5HT and NE participate in the modulation of endogenous analgesic mechanisms by way of the descending inhibitory pain pathways in the brain and spinal cord. Although the specific mechanism of action remains unclear, some studies have proposed that low levels of 5HT may be associated with increased sensitivity to pain - a condition that could subsequently be improved by milnacipran's capacity to enhance the presence of 5HT by inhibiting its reuptake via serotonin transporters at synaptic clefts. Furthermore, in the CNS it is also generally believed that NE released from descending pathways can mitigate pain sensations via eliciting inhibitory effects on alpha-2A-adrenoceptors on central terminals of primary afferent nociceptors, by direct alpha-2-adrenergic action on pain-relay neurons, and by alpha-1-adrenoceptor-mediated activation of inhibitory interneurons. Such NE pain mitigation is consequently also enhanced by milnacipran's ability to enhance the presence of NE by inhibiting its reuptake via norepinephrine transporters at synaptic clefts. Concurrently, milnacipran's capacity to inhibit the reuptake of both 5HT and NE also facilitates its treatment of MDD. Given the monoamine hypothesis' assertion that decreased 5HT can be associated with anxiety, obsessions, compulsions, and decreased NE can result in lowered alertness, energy, attention, and general interest in life, it is proposed that milnacipran's basic activities as a serotonin and norepinephrine reuptake inhibitor could assist in treating such symptoms of MDD by increasing the presence of both 5HT and NE in the body by inhibiting their reuptake. •Absorption (Drug A): Bupropion is currently available in 3 distinct, but bioequivalent formulations: immediate release (IR), sustained-release (SR), and extended-release (XL). Immediate Release Formulation In humans, following oral administration of bupropion hydrochloride tablets, peak plasma bupropion concentrations are usually achieved within 2 hours. IR formulations provide a short duration of action and are therefore generally dosed three times per day. Sustained Release Formulation In humans, following oral administration of bupropion hydrochloride sustained-release tablets (SR), peak plasma concentration (Cmax) of bupropion is usually achieved within 3 hours. SR formulations provide a 12-hour extended release of medication and are therefore generally dosed twice per day. Extended Release Formulation Following single oral administration of bupropion hydrochloride extended-release tablets (XL) to healthy volunteers, the median time to peak plasma concentrations for bupropion was approximately 5 hours. The presence of food did not affect the peak concentration or area under the curve of bupropion. XL formulations provide a 24-hour extended release of medication and are therefore generally dosed once per day/ In a trial comparing chronic dosing with bupropion hydrochloride extended-release tablets (SR) 150 mg twice daily to bupropion immediate-release formulation 100 mg 3 times daily, the steady state Cmax for bupropion after bupropion hydrochloride sustained-release tablets (SR) administration was approximately 85% of those achieved after bupropion immediate-release formulation administration. Exposure (AUC) to bupropion was equivalent for both formulations. Bioequivalence was also demonstrated for all three major active metabolites (i.e., hydroxybupropion, threohydrobupropion and erythrohydrobupropion) for both Cmax and AUC. Thus, at steady state, bupropion hydrochloride sustained-release tablets (SR) given twice daily, and the immediate-release formulation of bupropion given 3 times daily, are essentially bioequivalent for both bupropion and the 3 quantitatively important metabolites. Furthermore, in a study comparing 14-day dosing with bupropion hydrochloride extended-release tablets (XL), 300 mg once-daily to the immediate-release formulation of bupropion at 100 mg 3 times daily, equivalence was demonstrated for peak plasma concentration and area under the curve for bupropion and the three metabolites (hydroxybupropion, threohydrobupropion, and erythrohydrobupropion). Additionally, in a study comparing 14-day dosing with bupropion hydrochloride extended-release tablets (XL) 300 mg once daily to the sustained-release formulation of bupropion at 150 mg 2 times daily, equivalence was demonstrated for peak plasma concentration and area under the curve for bupropion and the three metabolites. Bupropion hydrochloride extended-release tablets (SR) can be taken with or without food. Bupropion Cmax and AUC were increased by 11% to 35% and 16% to 19%, respectively, when bupropion hydrochloride extended-release tablets (SR) was administered with food to healthy volunteers in three trials. The food effect is not considered clinically significant. Following a single-dose administration of bupropion hydrochloride extended-release tablets (SR) in humans, Cmax of bupropion's metabolite hydroxybupropion occurs approximately 6 hours post-dose and is approximately 10 times the peak level of the parent drug at steady state. The elimination half-life of hydroxybupropion is approximately 20 (±5) hours and its AUC at steady state is about 17 times that of bupropion. The times to peak concentrations for the erythrohydrobupropion and threohydrobupropion metabolites are similar to that of the hydroxybupropion metabolite. However, their elimination half-lives are longer, 33(±10) and 37 (±13) hours, respectively, and steady-state AUCs are 1.5 and 7 times that of bupropion, respectively. •Absorption (Drug B): Racemic milnacipram demonstrates an absolute bioavailability of about 85-90% following oral administration. Maximum concentrations of the racemic agent are reached within 2-4 hours after oral dosing, and steady-state levels are obtained by 36-48 hours. Conversely, the relative bioavailability of levomilnacipram has been documented as 92%. The median time to peak concentration Tmax for levomilnacipram is about 6-8 hours after oral administration. After daily dosing of levomilnacipram 120 mg, the mean Cmax value is 341 ng/mL, and the mean steady-state AUC value is 5196 ng.h/mL. In general, the administration of either racemic milnacipram or levomilnacipram with food does not affect the medication's oral bioavailability. •Volume of distribution (Drug A): No volume of distribution available •Volume of distribution (Drug B): The mean volume of distribution recorded for racemic milnacipran following a single intravenous dose to healthy subjects was approximately 400 L. Alternatively, levomilnacipran is widely distributed with an apparent volume of distribution of 387-473 L. •Protein binding (Drug A): In vitro tests show that bupropion is 84% bound to human plasma proteins at concentrations up to 200 mcg per mL. The extent of protein binding of the hydroxybupropion metabolite is similar to that for bupropion, whereas the extent of protein binding of the threohydrobupropion metabolite is about half that seen with bupropion. •Protein binding (Drug B): The protein binding determined for racemic milnacipran is 13%. Conversely, the plasma protein binding documented for levomilnacipran is 22% over a concentration range of 10 to 1000 ng/mL. •Metabolism (Drug A): Bupropion is extensively metabolized in humans. Three metabolites are active: hydroxybupropion, which is formed via hydroxylation of the tert-butyl group of bupropion, and the amino-alcohol isomers, threohydrobupropion and erythrohydrobupropion, which are formed via reduction of the carbonyl group. In vitro findings suggest that CYP2B6 is the principal isoenzyme involved in the formation of hydroxybupropion, while cytochrome P450 enzymes are not involved in the formation of threohydrobupropion. Hydroxybupropion has been shown to have the same affinity as bupropion for the norepinephrine transporter (NET) but approximately 50% of its antidepressant activity despite reaching concentrations of ~10-fold higher than that of the parent drug. Oxidation of the bupropion side chain results in the formation of a glycine conjugate of meta-chlorobenzoic acid, which is then excreted as the major urinary metabolite. The potency and toxicity of the metabolites relative to bupropion have not been fully characterized. However, it has been demonstrated in an antidepressant screening test in mice that hydroxybupropion is one-half as potent as bupropion, while threohydrobupropion and erythrohydrobupropion are 5-fold less potent than bupropion. This may be of clinical importance because the plasma concentrations of the metabolites are as high as or higher than those of bupropion. Bupropion and its metabolites exhibit linear kinetics following chronic administration of 300 to 450 mg per day. •Metabolism (Drug B): It has been determined that levomilnacipran undergoes desethylation and hydroxylation to generate desethyl levomilnacipran and p-hydroxy-levomilnacipran, respectively. Both oxidative metabolites undergo further conjugation with glucuronide to form the conjugate milnacipran carbamoyl-O-glucuronide. The desethylation is catalyzed primarily by CYP3A4 with minor contribution by CYP2C8, 2C19, 2D6, and 2J2. Additionally, it is the general understanding that there is no interconversion between the enantiomers of milnacipran in the body. •Route of elimination (Drug A): Bupropion is extensively metabolized in humans. Oxidation of the bupropion side chain results in the formation of a glycine conjugate of metachlorobenzoic acid, which is then excreted as the major urinary metabolite. Following oral administration of 200 mg of 14C-bupropion in humans, 87% and 10% of the radioactive dose were recovered in the urine and feces, respectively. However, the fraction of the oral dose of bupropion excreted unchanged was only 0.5%, a finding consistent with the extensive metabolism of bupropion. •Route of elimination (Drug B): Levomilnacipran and its metabolites are eliminated primarily by renal excretion. Following oral administration of 14C-levomilnacipran solution, approximately 58% of the dose is excreted in urine as unchanged levomilnacipran. N-desethyl levomilnacipran is the major metabolite excreted in the urine and accounted for approximately 18% of the dose. Other identifiable metabolites excreted in the urine are levomilnacipran glucuronide (4%), desethyl levomilnacipran glucuronide (3%), p-hydroxy levomilnacipran glucuronide (1%), and p-hydroxy levomilnacipran (1%). •Half-life (Drug A): 24 hours •Half-life (Drug B): The terminal elimination half-life documented for racemic milnacipran is approximately 6-8 hours, where d-milnacipran has a longer elimination half-life of 8-10 hours compared to that of the l-enantionmer at 4-6 hours. Alternatively, the terminal elimination half-life determined specifically for levomilnacipran formulations is about 12 hours. •Clearance (Drug A): No clearance available •Clearance (Drug B): The total plasma clearance determined for milnacipran is approximately 40 L/h. •Toxicity (Drug A): Symptoms of overdose include seizures, hallucinations, loss of consciousness, tachycardia, and cardiac arrest. •Toxicity (Drug B): There is limited clinical experience with milnacipran overdose in humans. In clinical trials, cases of acute ingestions up to 1000 mg daily were reported with none being fatal. In postmarketing experience, fatal outcomes have been reported for acute overdoses primarily involving multiple drugs but also with milnacipran only. The most common signs and symptoms of overdose included increased blood pressure, cardio-respiratory arrest, changes in the level of consciousness (ranging from somnolence to coma), confusional state, dizziness, and increased hepatic enzymes. There are no adequate and well-controlled studies in pregnant women. In fact, milnacipram should be used during pregnancy only if the potential benefit justifies the potential risk to the fetus. Neonates exposed to SSRIs or SNRIs, late in the third trimester have developed complications requiring prolonged hospitalization, respiratory support, and tube feeding. Such complications can arise immediately upon delivery. Reported clinical findings have included respiratory distress, cyanosis, apnea, seizures, temperature instability, feeding difficulty, vomiting, hypoglycemia, hypotonia, hypertonia, hyperreflexia, tremor, jitteriness, irritability, and constant crying. These features are consistent with either a direct toxic effect of SNRI class drugs like milnacipran or, possibly, a drug discontinuation syndrome. It should be noted that, in some cases, the clinical picture is consistent with serotonin syndrome. The effect of milnacipran on labor and delivery in humans is unknown. Milnacipran should be used during labor and delivery only if the potential benefits outweigh the potential risks. There are no adequate and well-controlled studies in nursing mothers. It is not known if milnacipran is excreted in human milk. Studies have shown that levomilnacipran is excreted into the milk of lactating rats. Subsequently, possible excretion into human milk possesses the potential for serious adverse reactions in nursing infants. As a consequence, breastfeeding by women treated with levomilnacipran should be considered only if the potential benefits outweigh the potential risks to the child. Milnacipran is not indicated for use in children under 18 years of age due to concerns over the potential for agitation-type emotional and behavioral changes, as well as suicidal ideation and/or behavior. SNRIs like milnacipran have been associated with cases of clinically significant hyponatremia in elderly patients, who may be at greater risk for this adverse event. Levomilnacipran was not mutagenic when evaluated in vitro in a bacterial mutagenicity study (Ames test) and not genotoxic in a mouse lymphoma study. It was not clastogenic in an in vivo micronucleus assay in rats. The potential effects of levomilnacipran on gonadal function, mating behavior, reproductive performance and early pregnancy were evaluated in rats at oral doses of 0, 10, 30, or 100 mg/kg/day. The NOAEL was 100 mg/kg/day based on reductions in body weight gain and food consumption. There were no levomilnacipran effects on male and female fertility parameters. In the rat and rabbit embryo/fetal development studies, decreases in maternal body weight gain and food consumption were noted. In the fetuses, increases in the incidence of ossification anomalies were noted but were of no toxicological significance. In both species, the NOAEL was determined to be 100 mg/kg/day, a dose which represents a rat or rabbit animal-to-human exposure margin of 9-fold and 4-fold, respectively relative to the human exposure from 120 mg/day of levomilnacipran. Material safety data for milnacipran has documented the LD50 oral value in the rat model as being 213 mg/kg. •Brand Names (Drug A): Aplenzin, Auvelity, Budeprion, Contrave, Forfivo, Wellbutrin, Zyban •Brand Names (Drug B): Savella •Synonyms (Drug A): No synonyms listed •Synonyms (Drug B): Midalcipran Milnacipran Milnacipranum •Summary (Drug A): Bupropion is a norepinephrine and dopamine reuptake inhibitor used in the treatment of major depressive disorder (MDD), seasonal affective disorder (SAD), and as an aid to smoking cessation. •Summary (Drug B): Milnacipran is a selective serotonin and norepinephrine reuptake inhibitor (SNRI) used for the treatment of fibromyalgia and a short-term treatment of major depressive disorder. Output: Depending on the central nervous system depressant, some drugs may interact with selective serotonin reuptake inhibitors, causing a variety of CNS effects. Effects can range from mild sedation to severe respiratory depression and may be caused by a variety of mechanisms, either pharmacodynamically or pharmacokinetically. The severity of drug interaction effects differs between different combinations of CNS depressants and SSRIs, depending on factors such as affinity to CYP450 enzymes, drug half-lives, and mechanism of action.. However, due to their specific mechanism of action and extensive liver metabolism, SSRIs drug interactions tend to be mediated through liver enzymes more often. Additionally, when combined with other CNS depressants, SSRIs are not equivalent in their potential to induce drug-drug interaction. The severity of the interaction is moderate.

Does Bupropion and Milrinone interact?

•Drug A: Bupropion •Drug B: Milrinone •Severity: MINOR •Description: Milrinone may decrease the excretion rate of Bupropion which could result in a higher serum level. •Extended Description: The renal excretion of drugs is the overall result of a combination of kidney processes that include glomerular filtration, passive diffusion, tubular secretion, and tubular reabsorption. Since two of these mechanisms - tubular secretion and reabsorption - are saturable processes , they are consequently susceptible to competition between multiple substrates excreted by the kidneys. If two or more medications that are mainly renally excreted are co-administered, they may compete for renal elimination; there is a large likelihood that one agent may "out-compete" or saturate the renal excretion mechanisms before the other concomitantly administered agent(s) are excreted. As a result, the elimination of these other concurrently administered agents may be inhibited or otherwise delayed, which could lead to increases in their serum concentrations and the risk, incidence, and/or severity of adverse effects associated with the exposure to such drugs. •Indication (Drug A): Bupropion is indicated for the treatment of major depressive disorder (MDD), seasonal affective disorder (SAD), and as an aid to smoking cessation. When used in combination with naltrexone as the marketed product ContraveⓇ, bupropion is indicated as an adjunct to a reduced-calorie diet and increased physical activity for chronic weight management in adults with an initial body mass index (BMI) of: 30 kg/m^2 or greater (obese) or 27 kg/m^2 or greater (overweight) in the presence of at least one weight-related comorbid condition (e.g., hypertension, type 2 diabetes mellitus, or dyslipidemia). Bupropion is also used off-label as a first-line treatment in patients with ADHD and comorbid bipolar disorder when used as an adjunct to mood stabilizers. •Indication (Drug B): Milrinone is indicated for the short-term (48 hours or less) treatment of patients with acute decompensated heart failure. Milrinone administration should occur together with close monitoring using appropriate electrocardiographic equipment and should occur in a facility equipped for the immediate treatment of potential cardiac events, including ventricular arrhythmias. •Pharmacodynamics (Drug A): Bupropion is chemically unrelated to tricyclic, tetracyclic, selective serotonin re-uptake inhibitors, or other known antidepressant agents. Compared to classical tricyclic antidepressants, Bupropion is a relatively weak inhibitor of the neuronal uptake of norepinephrine and dopamine. In addition, Bupropion does not inhibit monoamine oxidase. Bupropion has been found to be essentially inactive at the serotonin transporter (SERT)(IC50 >10 000 nM), however both bupropion and its primary metabolite hydroxybupropion have been found to block the function of cation-selective serotonin type 3A receptors (5-HT3ARs). Bupropion produces dose-related central nervous system (CNS) stimulant effects in animals, as evidenced by increased locomotor activity, increased rates of responding in various schedule-controlled operant behaviour tasks, and, at high doses, induction of mild stereotyped behaviour. Due to these stimulant effects and selective activity at dopamine and norepinephrine receptors, bupropion has been identified as having an abuse potential. Bupropion has a similar structure to the controlled substance Cathinone, and has been identified as having mild amphetamine-like activity, particularly when inhaled or injected. Bupropion is also known to lower the seizure threshold, making any pre-existing seizure conditions a contraindication to its use. This risk is exacerbated when bupropion is combined with other drugs or substances that lower the seizure threshold, such as cocaine, or in clinical situations that would increase the risk of a seizure such as abrupt alcohol or benzodiazepine withdrawal. As norepinephrine has been shown to have anticonvulsant properties, bupropion's inhibitory effects on NET are thought to contribute to its pro-convulsant activity. Bupropion has been shown to increase blood pressure and pose a risk for exacerbation of unmanaged or pre-existing hypertension, however, clinical trials of bupropion in smokers with CVD have not identified an increased incidence of CV events including stroke or heart attack. In clinical trials, the mean increase in systolic blood pressure associated with the use of bupropion was found to be 1.3 mmHg. •Pharmacodynamics (Drug B): Milrinone is a bipyridine derivative with positive inotropic and lusitropic effects that also results in peripheral vasodilation with minimal chronotropic effects over a therapeutic range of 100 to 300 ng/mL. As such, milrinone is used in decompensated congestive heart failure. Studies have demonstrated that milrinone exhibits sigmoidal effects, such that increasing milrinone plasma concentrations beyond a certain level results in no further hemodynamic changes. Despite milrinone's benefits, both intravenous and oral use has been associated with increased frequency of ventricular arrhythmias, and long-term oral use has been associated with an increased risk of sudden death; in general, there are no data to support the safety or efficacy of milrinone use beyond 48 hours and patients should be monitored closely for cardiac dysfunction. Also, as milrinone is primarily excreted renally, dose adjustments may be required in patients with impaired renal function. •Mechanism of action (Drug A): Bupropion is a norepinephrine/dopamine-reuptake inhibitor (NDRI) that exerts its pharmacological effects by weakly inhibiting the enzymes involved in the uptake of the neurotransmitters norepinephrine and dopamine from the synaptic cleft, therefore prolonging their duration of action within the neuronal synapse and the downstream effects of these neurotransmitters. More specifically, bupropion binds to the norepinephrine transporter (NET) and the dopamine transporter (DAT). Bupropion was originally classified as an "atypical" antidepressant because it does not exert the same effects as the classical antidepressants such as Monoamine Oxidase Inhibitors (MAOIs), Tricyclic Antidepressants (TCAs), or Selective Serotonin Reuptake Inhibitors (SSRIs). While it has comparable effectiveness to typical first-line options for the treatment of depression such as SSRIs, bupropion is a unique option for the treatment of MDD as it lacks any clinically relevant serotonergic effects, typical of other mood medications, or any effects on histamine or adrenaline receptors. Lack of activity at these receptors results in a more tolerable side effect profile; bupropion is less likely to cause sexual side effects, sedation, or weight gain as compared to SSRIs or TCAs, for example. When used as an aid to smoking cessation, bupropion is thought to confer its anti-craving and anti-withdrawal effects by inhibiting dopamine reuptake, which is thought to be involved in the reward pathways associated with nicotine, and through the antagonism of the nicotinic acetylcholinergic receptor (AChR), thereby blunting the effects of nicotine. Furthermore, the stimulatory effects produced by bupropion in the central nervous system are similar to nicotine's effects, making low doses of bupropion a suitable option as a nicotine substitute. When used in combination with naltrexone in the marketed product ContraveⓇ for chronic weight management, the two components are thought to have effects on areas of the brain involved in the regulation of food intake. This includes the hypothalamus, which is involved in appetite regulation, and the mesolimbic dopamine circuit, which is involved in reward pathways. Studies have shown that the combined activity of bupropion and naltrexone increase the firing rate of hypothalamic pro-opiomelanocortin (POMC) neurons and blockade of opioid receptor-mediated POMC auto-inhibition, which are associated with a reduction in food intake and increased energy expenditure. This combination was also found to reduce food intake when injected directly into the ventral tegmental area of the mesolimbic circuit in mice, which is an area associated with the regulation of reward pathways. •Mechanism of action (Drug B): Heart failure is a condition characterized by the heart's inability to provide adequate perfusion to the peripheral tissues, resulting in systemic symptoms including pulmonary, gastrointestinal, renal, and cerebral dysfunction. Although the biochemical and physiological processes underlying heart failure complex and variable, one such physiological response regulated by the sympathetic nervous system involves the eventual downregulation of cardiac β-receptors, decreased catecholamine sensitivity, and a corresponding decrease in adenylyl-cyclase-mediated signalling pathways. Increased intracellular cAMP, mainly acting through protein kinase A, increases sarcolemmal calcium release through L-type calcium channels as well as calcium re-uptake mediated by phospholamban and troponin I; these actions correspond to positive inotropic and lusitropic effects, respectively. Milrinone is a partial competitive inhibitor of phosphodiesterase III (PDE-III), with a measured IC 50 value of between 0.66 and 1.3 μM. As a PDE-III inhibitor, milrinone results in an increase in intracellular cAMP, responsible for its pharmacological effects, including positive inotropy, positive lusitropy, and vasodilation. As milrinone affects cAMP levels through PDE-III and not through β-adrenergic receptors, it is effective in patients who have downregulated or otherwise desensitized β-adrenergic receptors and can be administered together with β-agonists/antagonists. •Absorption (Drug A): Bupropion is currently available in 3 distinct, but bioequivalent formulations: immediate release (IR), sustained-release (SR), and extended-release (XL). Immediate Release Formulation In humans, following oral administration of bupropion hydrochloride tablets, peak plasma bupropion concentrations are usually achieved within 2 hours. IR formulations provide a short duration of action and are therefore generally dosed three times per day. Sustained Release Formulation In humans, following oral administration of bupropion hydrochloride sustained-release tablets (SR), peak plasma concentration (Cmax) of bupropion is usually achieved within 3 hours. SR formulations provide a 12-hour extended release of medication and are therefore generally dosed twice per day. Extended Release Formulation Following single oral administration of bupropion hydrochloride extended-release tablets (XL) to healthy volunteers, the median time to peak plasma concentrations for bupropion was approximately 5 hours. The presence of food did not affect the peak concentration or area under the curve of bupropion. XL formulations provide a 24-hour extended release of medication and are therefore generally dosed once per day/ In a trial comparing chronic dosing with bupropion hydrochloride extended-release tablets (SR) 150 mg twice daily to bupropion immediate-release formulation 100 mg 3 times daily, the steady state Cmax for bupropion after bupropion hydrochloride sustained-release tablets (SR) administration was approximately 85% of those achieved after bupropion immediate-release formulation administration. Exposure (AUC) to bupropion was equivalent for both formulations. Bioequivalence was also demonstrated for all three major active metabolites (i.e., hydroxybupropion, threohydrobupropion and erythrohydrobupropion) for both Cmax and AUC. Thus, at steady state, bupropion hydrochloride sustained-release tablets (SR) given twice daily, and the immediate-release formulation of bupropion given 3 times daily, are essentially bioequivalent for both bupropion and the 3 quantitatively important metabolites. Furthermore, in a study comparing 14-day dosing with bupropion hydrochloride extended-release tablets (XL), 300 mg once-daily to the immediate-release formulation of bupropion at 100 mg 3 times daily, equivalence was demonstrated for peak plasma concentration and area under the curve for bupropion and the three metabolites (hydroxybupropion, threohydrobupropion, and erythrohydrobupropion). Additionally, in a study comparing 14-day dosing with bupropion hydrochloride extended-release tablets (XL) 300 mg once daily to the sustained-release formulation of bupropion at 150 mg 2 times daily, equivalence was demonstrated for peak plasma concentration and area under the curve for bupropion and the three metabolites. Bupropion hydrochloride extended-release tablets (SR) can be taken with or without food. Bupropion Cmax and AUC were increased by 11% to 35% and 16% to 19%, respectively, when bupropion hydrochloride extended-release tablets (SR) was administered with food to healthy volunteers in three trials. The food effect is not considered clinically significant. Following a single-dose administration of bupropion hydrochloride extended-release tablets (SR) in humans, Cmax of bupropion's metabolite hydroxybupropion occurs approximately 6 hours post-dose and is approximately 10 times the peak level of the parent drug at steady state. The elimination half-life of hydroxybupropion is approximately 20 (±5) hours and its AUC at steady state is about 17 times that of bupropion. The times to peak concentrations for the erythrohydrobupropion and threohydrobupropion metabolites are similar to that of the hydroxybupropion metabolite. However, their elimination half-lives are longer, 33(±10) and 37 (±13) hours, respectively, and steady-state AUCs are 1.5 and 7 times that of bupropion, respectively. •Absorption (Drug B): When administered as an IV bolus dose of 10-100 μg/kg, milrinone induces hemodynamic effects within 60 seconds reaching a peak effect by 2-5 minutes. The plasma AUC is significantly dose-dependent. •Volume of distribution (Drug A): No volume of distribution available •Volume of distribution (Drug B): Milrinone administered intravenously to congestive heart failure patients had a volume of distribution of 0.38 L/kg (injections between 12.5-125 μg/kg) and 0.45 L/kg (infusions between 0.2-0.7 μg/kg/min. •Protein binding (Drug A): In vitro tests show that bupropion is 84% bound to human plasma proteins at concentrations up to 200 mcg per mL. The extent of protein binding of the hydroxybupropion metabolite is similar to that for bupropion, whereas the extent of protein binding of the threohydrobupropion metabolite is about half that seen with bupropion. •Protein binding (Drug B): Milrinone is approximately 70% bound to human plasma proteins. •Metabolism (Drug A): Bupropion is extensively metabolized in humans. Three metabolites are active: hydroxybupropion, which is formed via hydroxylation of the tert-butyl group of bupropion, and the amino-alcohol isomers, threohydrobupropion and erythrohydrobupropion, which are formed via reduction of the carbonyl group. In vitro findings suggest that CYP2B6 is the principal isoenzyme involved in the formation of hydroxybupropion, while cytochrome P450 enzymes are not involved in the formation of threohydrobupropion. Hydroxybupropion has been shown to have the same affinity as bupropion for the norepinephrine transporter (NET) but approximately 50% of its antidepressant activity despite reaching concentrations of ~10-fold higher than that of the parent drug. Oxidation of the bupropion side chain results in the formation of a glycine conjugate of meta-chlorobenzoic acid, which is then excreted as the major urinary metabolite. The potency and toxicity of the metabolites relative to bupropion have not been fully characterized. However, it has been demonstrated in an antidepressant screening test in mice that hydroxybupropion is one-half as potent as bupropion, while threohydrobupropion and erythrohydrobupropion are 5-fold less potent than bupropion. This may be of clinical importance because the plasma concentrations of the metabolites are as high as or higher than those of bupropion. Bupropion and its metabolites exhibit linear kinetics following chronic administration of 300 to 450 mg per day. •Metabolism (Drug B): Animal studies suggest that two oxidative pathways are involved in milrinone metabolism, albeit only involving a small proportion of the administered dose. The major metabolite is the O-glucuronide metabolite. •Route of elimination (Drug A): Bupropion is extensively metabolized in humans. Oxidation of the bupropion side chain results in the formation of a glycine conjugate of metachlorobenzoic acid, which is then excreted as the major urinary metabolite. Following oral administration of 200 mg of 14C-bupropion in humans, 87% and 10% of the radioactive dose were recovered in the urine and feces, respectively. However, the fraction of the oral dose of bupropion excreted unchanged was only 0.5%, a finding consistent with the extensive metabolism of bupropion. •Route of elimination (Drug B): Milrinone is primarily excreted in the urine, with 60% of a dose recovered after two hours and 90% within eight hours. Approximately 83% of milrinone recovered in urine is unchanged while 12% is present as the main O-glucuronide metabolite. •Half-life (Drug A): 24 hours •Half-life (Drug B): Milrinone administered intravenously to congestive heart failure patients had a mean terminal elimination half-life of 2.3 hours (injections between 12.5-125 μg/kg) and 2.4 hours (infusions between 0.2-0.7 μg/kg/min. •Clearance (Drug A): No clearance available •Clearance (Drug B): Milrinone administered intravenously to congestive heart failure patients had a clearance of 0.13 L/kg/hr (injections between 12.5-125 μg/kg) and 0.14 L/kg/hr (infusions between 0.2-0.7 μg/kg/min. •Toxicity (Drug A): Symptoms of overdose include seizures, hallucinations, loss of consciousness, tachycardia, and cardiac arrest. •Toxicity (Drug B): Toxicity information regarding milrinone is not readily available. Patients experiencing an overdose are at an increased risk of severe adverse effects such as hypotension and adverse cardiac events such as ventricular arrhythmias. Symptomatic and supportive measures are recommended. •Brand Names (Drug A): Aplenzin, Auvelity, Budeprion, Contrave, Forfivo, Wellbutrin, Zyban •Brand Names (Drug B): No brand names available •Synonyms (Drug A): No synonyms listed •Synonyms (Drug B): Milrinona Milrinone Milrinonum •Summary (Drug A): Bupropion is a norepinephrine and dopamine reuptake inhibitor used in the treatment of major depressive disorder (MDD), seasonal affective disorder (SAD), and as an aid to smoking cessation. •Summary (Drug B): Milrinone is a PDE-III inhibitor with inotropic, lusitropic, and vasodilatory properties used for the short-term treatment of acute decompensated heart failure.

The renal excretion of drugs is the overall result of a combination of kidney processes that include glomerular filtration, passive diffusion, tubular secretion, and tubular reabsorption. Since two of these mechanisms - tubular secretion and reabsorption - are saturable processes , they are consequently susceptible to competition between multiple substrates excreted by the kidneys. If two or more medications that are mainly renally excreted are co-administered, they may compete for renal elimination; there is a large likelihood that one agent may "out-compete" or saturate the renal excretion mechanisms before the other concomitantly administered agent(s) are excreted. As a result, the elimination of these other concurrently administered agents may be inhibited or otherwise delayed, which could lead to increases in their serum concentrations and the risk, incidence, and/or severity of adverse effects associated with the exposure to such drugs. The severity of the interaction is minor.

Question: Does Bupropion and Milrinone interact? Information: •Drug A: Bupropion •Drug B: Milrinone •Severity: MINOR •Description: Milrinone may decrease the excretion rate of Bupropion which could result in a higher serum level. •Extended Description: The renal excretion of drugs is the overall result of a combination of kidney processes that include glomerular filtration, passive diffusion, tubular secretion, and tubular reabsorption. Since two of these mechanisms - tubular secretion and reabsorption - are saturable processes , they are consequently susceptible to competition between multiple substrates excreted by the kidneys. If two or more medications that are mainly renally excreted are co-administered, they may compete for renal elimination; there is a large likelihood that one agent may "out-compete" or saturate the renal excretion mechanisms before the other concomitantly administered agent(s) are excreted. As a result, the elimination of these other concurrently administered agents may be inhibited or otherwise delayed, which could lead to increases in their serum concentrations and the risk, incidence, and/or severity of adverse effects associated with the exposure to such drugs. •Indication (Drug A): Bupropion is indicated for the treatment of major depressive disorder (MDD), seasonal affective disorder (SAD), and as an aid to smoking cessation. When used in combination with naltrexone as the marketed product ContraveⓇ, bupropion is indicated as an adjunct to a reduced-calorie diet and increased physical activity for chronic weight management in adults with an initial body mass index (BMI) of: 30 kg/m^2 or greater (obese) or 27 kg/m^2 or greater (overweight) in the presence of at least one weight-related comorbid condition (e.g., hypertension, type 2 diabetes mellitus, or dyslipidemia). Bupropion is also used off-label as a first-line treatment in patients with ADHD and comorbid bipolar disorder when used as an adjunct to mood stabilizers. •Indication (Drug B): Milrinone is indicated for the short-term (48 hours or less) treatment of patients with acute decompensated heart failure. Milrinone administration should occur together with close monitoring using appropriate electrocardiographic equipment and should occur in a facility equipped for the immediate treatment of potential cardiac events, including ventricular arrhythmias. •Pharmacodynamics (Drug A): Bupropion is chemically unrelated to tricyclic, tetracyclic, selective serotonin re-uptake inhibitors, or other known antidepressant agents. Compared to classical tricyclic antidepressants, Bupropion is a relatively weak inhibitor of the neuronal uptake of norepinephrine and dopamine. In addition, Bupropion does not inhibit monoamine oxidase. Bupropion has been found to be essentially inactive at the serotonin transporter (SERT)(IC50 >10 000 nM), however both bupropion and its primary metabolite hydroxybupropion have been found to block the function of cation-selective serotonin type 3A receptors (5-HT3ARs). Bupropion produces dose-related central nervous system (CNS) stimulant effects in animals, as evidenced by increased locomotor activity, increased rates of responding in various schedule-controlled operant behaviour tasks, and, at high doses, induction of mild stereotyped behaviour. Due to these stimulant effects and selective activity at dopamine and norepinephrine receptors, bupropion has been identified as having an abuse potential. Bupropion has a similar structure to the controlled substance Cathinone, and has been identified as having mild amphetamine-like activity, particularly when inhaled or injected. Bupropion is also known to lower the seizure threshold, making any pre-existing seizure conditions a contraindication to its use. This risk is exacerbated when bupropion is combined with other drugs or substances that lower the seizure threshold, such as cocaine, or in clinical situations that would increase the risk of a seizure such as abrupt alcohol or benzodiazepine withdrawal. As norepinephrine has been shown to have anticonvulsant properties, bupropion's inhibitory effects on NET are thought to contribute to its pro-convulsant activity. Bupropion has been shown to increase blood pressure and pose a risk for exacerbation of unmanaged or pre-existing hypertension, however, clinical trials of bupropion in smokers with CVD have not identified an increased incidence of CV events including stroke or heart attack. In clinical trials, the mean increase in systolic blood pressure associated with the use of bupropion was found to be 1.3 mmHg. •Pharmacodynamics (Drug B): Milrinone is a bipyridine derivative with positive inotropic and lusitropic effects that also results in peripheral vasodilation with minimal chronotropic effects over a therapeutic range of 100 to 300 ng/mL. As such, milrinone is used in decompensated congestive heart failure. Studies have demonstrated that milrinone exhibits sigmoidal effects, such that increasing milrinone plasma concentrations beyond a certain level results in no further hemodynamic changes. Despite milrinone's benefits, both intravenous and oral use has been associated with increased frequency of ventricular arrhythmias, and long-term oral use has been associated with an increased risk of sudden death; in general, there are no data to support the safety or efficacy of milrinone use beyond 48 hours and patients should be monitored closely for cardiac dysfunction. Also, as milrinone is primarily excreted renally, dose adjustments may be required in patients with impaired renal function. •Mechanism of action (Drug A): Bupropion is a norepinephrine/dopamine-reuptake inhibitor (NDRI) that exerts its pharmacological effects by weakly inhibiting the enzymes involved in the uptake of the neurotransmitters norepinephrine and dopamine from the synaptic cleft, therefore prolonging their duration of action within the neuronal synapse and the downstream effects of these neurotransmitters. More specifically, bupropion binds to the norepinephrine transporter (NET) and the dopamine transporter (DAT). Bupropion was originally classified as an "atypical" antidepressant because it does not exert the same effects as the classical antidepressants such as Monoamine Oxidase Inhibitors (MAOIs), Tricyclic Antidepressants (TCAs), or Selective Serotonin Reuptake Inhibitors (SSRIs). While it has comparable effectiveness to typical first-line options for the treatment of depression such as SSRIs, bupropion is a unique option for the treatment of MDD as it lacks any clinically relevant serotonergic effects, typical of other mood medications, or any effects on histamine or adrenaline receptors. Lack of activity at these receptors results in a more tolerable side effect profile; bupropion is less likely to cause sexual side effects, sedation, or weight gain as compared to SSRIs or TCAs, for example. When used as an aid to smoking cessation, bupropion is thought to confer its anti-craving and anti-withdrawal effects by inhibiting dopamine reuptake, which is thought to be involved in the reward pathways associated with nicotine, and through the antagonism of the nicotinic acetylcholinergic receptor (AChR), thereby blunting the effects of nicotine. Furthermore, the stimulatory effects produced by bupropion in the central nervous system are similar to nicotine's effects, making low doses of bupropion a suitable option as a nicotine substitute. When used in combination with naltrexone in the marketed product ContraveⓇ for chronic weight management, the two components are thought to have effects on areas of the brain involved in the regulation of food intake. This includes the hypothalamus, which is involved in appetite regulation, and the mesolimbic dopamine circuit, which is involved in reward pathways. Studies have shown that the combined activity of bupropion and naltrexone increase the firing rate of hypothalamic pro-opiomelanocortin (POMC) neurons and blockade of opioid receptor-mediated POMC auto-inhibition, which are associated with a reduction in food intake and increased energy expenditure. This combination was also found to reduce food intake when injected directly into the ventral tegmental area of the mesolimbic circuit in mice, which is an area associated with the regulation of reward pathways. •Mechanism of action (Drug B): Heart failure is a condition characterized by the heart's inability to provide adequate perfusion to the peripheral tissues, resulting in systemic symptoms including pulmonary, gastrointestinal, renal, and cerebral dysfunction. Although the biochemical and physiological processes underlying heart failure complex and variable, one such physiological response regulated by the sympathetic nervous system involves the eventual downregulation of cardiac β-receptors, decreased catecholamine sensitivity, and a corresponding decrease in adenylyl-cyclase-mediated signalling pathways. Increased intracellular cAMP, mainly acting through protein kinase A, increases sarcolemmal calcium release through L-type calcium channels as well as calcium re-uptake mediated by phospholamban and troponin I; these actions correspond to positive inotropic and lusitropic effects, respectively. Milrinone is a partial competitive inhibitor of phosphodiesterase III (PDE-III), with a measured IC 50 value of between 0.66 and 1.3 μM. As a PDE-III inhibitor, milrinone results in an increase in intracellular cAMP, responsible for its pharmacological effects, including positive inotropy, positive lusitropy, and vasodilation. As milrinone affects cAMP levels through PDE-III and not through β-adrenergic receptors, it is effective in patients who have downregulated or otherwise desensitized β-adrenergic receptors and can be administered together with β-agonists/antagonists. •Absorption (Drug A): Bupropion is currently available in 3 distinct, but bioequivalent formulations: immediate release (IR), sustained-release (SR), and extended-release (XL). Immediate Release Formulation In humans, following oral administration of bupropion hydrochloride tablets, peak plasma bupropion concentrations are usually achieved within 2 hours. IR formulations provide a short duration of action and are therefore generally dosed three times per day. Sustained Release Formulation In humans, following oral administration of bupropion hydrochloride sustained-release tablets (SR), peak plasma concentration (Cmax) of bupropion is usually achieved within 3 hours. SR formulations provide a 12-hour extended release of medication and are therefore generally dosed twice per day. Extended Release Formulation Following single oral administration of bupropion hydrochloride extended-release tablets (XL) to healthy volunteers, the median time to peak plasma concentrations for bupropion was approximately 5 hours. The presence of food did not affect the peak concentration or area under the curve of bupropion. XL formulations provide a 24-hour extended release of medication and are therefore generally dosed once per day/ In a trial comparing chronic dosing with bupropion hydrochloride extended-release tablets (SR) 150 mg twice daily to bupropion immediate-release formulation 100 mg 3 times daily, the steady state Cmax for bupropion after bupropion hydrochloride sustained-release tablets (SR) administration was approximately 85% of those achieved after bupropion immediate-release formulation administration. Exposure (AUC) to bupropion was equivalent for both formulations. Bioequivalence was also demonstrated for all three major active metabolites (i.e., hydroxybupropion, threohydrobupropion and erythrohydrobupropion) for both Cmax and AUC. Thus, at steady state, bupropion hydrochloride sustained-release tablets (SR) given twice daily, and the immediate-release formulation of bupropion given 3 times daily, are essentially bioequivalent for both bupropion and the 3 quantitatively important metabolites. Furthermore, in a study comparing 14-day dosing with bupropion hydrochloride extended-release tablets (XL), 300 mg once-daily to the immediate-release formulation of bupropion at 100 mg 3 times daily, equivalence was demonstrated for peak plasma concentration and area under the curve for bupropion and the three metabolites (hydroxybupropion, threohydrobupropion, and erythrohydrobupropion). Additionally, in a study comparing 14-day dosing with bupropion hydrochloride extended-release tablets (XL) 300 mg once daily to the sustained-release formulation of bupropion at 150 mg 2 times daily, equivalence was demonstrated for peak plasma concentration and area under the curve for bupropion and the three metabolites. Bupropion hydrochloride extended-release tablets (SR) can be taken with or without food. Bupropion Cmax and AUC were increased by 11% to 35% and 16% to 19%, respectively, when bupropion hydrochloride extended-release tablets (SR) was administered with food to healthy volunteers in three trials. The food effect is not considered clinically significant. Following a single-dose administration of bupropion hydrochloride extended-release tablets (SR) in humans, Cmax of bupropion's metabolite hydroxybupropion occurs approximately 6 hours post-dose and is approximately 10 times the peak level of the parent drug at steady state. The elimination half-life of hydroxybupropion is approximately 20 (±5) hours and its AUC at steady state is about 17 times that of bupropion. The times to peak concentrations for the erythrohydrobupropion and threohydrobupropion metabolites are similar to that of the hydroxybupropion metabolite. However, their elimination half-lives are longer, 33(±10) and 37 (±13) hours, respectively, and steady-state AUCs are 1.5 and 7 times that of bupropion, respectively. •Absorption (Drug B): When administered as an IV bolus dose of 10-100 μg/kg, milrinone induces hemodynamic effects within 60 seconds reaching a peak effect by 2-5 minutes. The plasma AUC is significantly dose-dependent. •Volume of distribution (Drug A): No volume of distribution available •Volume of distribution (Drug B): Milrinone administered intravenously to congestive heart failure patients had a volume of distribution of 0.38 L/kg (injections between 12.5-125 μg/kg) and 0.45 L/kg (infusions between 0.2-0.7 μg/kg/min. •Protein binding (Drug A): In vitro tests show that bupropion is 84% bound to human plasma proteins at concentrations up to 200 mcg per mL. The extent of protein binding of the hydroxybupropion metabolite is similar to that for bupropion, whereas the extent of protein binding of the threohydrobupropion metabolite is about half that seen with bupropion. •Protein binding (Drug B): Milrinone is approximately 70% bound to human plasma proteins. •Metabolism (Drug A): Bupropion is extensively metabolized in humans. Three metabolites are active: hydroxybupropion, which is formed via hydroxylation of the tert-butyl group of bupropion, and the amino-alcohol isomers, threohydrobupropion and erythrohydrobupropion, which are formed via reduction of the carbonyl group. In vitro findings suggest that CYP2B6 is the principal isoenzyme involved in the formation of hydroxybupropion, while cytochrome P450 enzymes are not involved in the formation of threohydrobupropion. Hydroxybupropion has been shown to have the same affinity as bupropion for the norepinephrine transporter (NET) but approximately 50% of its antidepressant activity despite reaching concentrations of ~10-fold higher than that of the parent drug. Oxidation of the bupropion side chain results in the formation of a glycine conjugate of meta-chlorobenzoic acid, which is then excreted as the major urinary metabolite. The potency and toxicity of the metabolites relative to bupropion have not been fully characterized. However, it has been demonstrated in an antidepressant screening test in mice that hydroxybupropion is one-half as potent as bupropion, while threohydrobupropion and erythrohydrobupropion are 5-fold less potent than bupropion. This may be of clinical importance because the plasma concentrations of the metabolites are as high as or higher than those of bupropion. Bupropion and its metabolites exhibit linear kinetics following chronic administration of 300 to 450 mg per day. •Metabolism (Drug B): Animal studies suggest that two oxidative pathways are involved in milrinone metabolism, albeit only involving a small proportion of the administered dose. The major metabolite is the O-glucuronide metabolite. •Route of elimination (Drug A): Bupropion is extensively metabolized in humans. Oxidation of the bupropion side chain results in the formation of a glycine conjugate of metachlorobenzoic acid, which is then excreted as the major urinary metabolite. Following oral administration of 200 mg of 14C-bupropion in humans, 87% and 10% of the radioactive dose were recovered in the urine and feces, respectively. However, the fraction of the oral dose of bupropion excreted unchanged was only 0.5%, a finding consistent with the extensive metabolism of bupropion. •Route of elimination (Drug B): Milrinone is primarily excreted in the urine, with 60% of a dose recovered after two hours and 90% within eight hours. Approximately 83% of milrinone recovered in urine is unchanged while 12% is present as the main O-glucuronide metabolite. •Half-life (Drug A): 24 hours •Half-life (Drug B): Milrinone administered intravenously to congestive heart failure patients had a mean terminal elimination half-life of 2.3 hours (injections between 12.5-125 μg/kg) and 2.4 hours (infusions between 0.2-0.7 μg/kg/min. •Clearance (Drug A): No clearance available •Clearance (Drug B): Milrinone administered intravenously to congestive heart failure patients had a clearance of 0.13 L/kg/hr (injections between 12.5-125 μg/kg) and 0.14 L/kg/hr (infusions between 0.2-0.7 μg/kg/min. •Toxicity (Drug A): Symptoms of overdose include seizures, hallucinations, loss of consciousness, tachycardia, and cardiac arrest. •Toxicity (Drug B): Toxicity information regarding milrinone is not readily available. Patients experiencing an overdose are at an increased risk of severe adverse effects such as hypotension and adverse cardiac events such as ventricular arrhythmias. Symptomatic and supportive measures are recommended. •Brand Names (Drug A): Aplenzin, Auvelity, Budeprion, Contrave, Forfivo, Wellbutrin, Zyban •Brand Names (Drug B): No brand names available •Synonyms (Drug A): No synonyms listed •Synonyms (Drug B): Milrinona Milrinone Milrinonum •Summary (Drug A): Bupropion is a norepinephrine and dopamine reuptake inhibitor used in the treatment of major depressive disorder (MDD), seasonal affective disorder (SAD), and as an aid to smoking cessation. •Summary (Drug B): Milrinone is a PDE-III inhibitor with inotropic, lusitropic, and vasodilatory properties used for the short-term treatment of acute decompensated heart failure. Output: The renal excretion of drugs is the overall result of a combination of kidney processes that include glomerular filtration, passive diffusion, tubular secretion, and tubular reabsorption. Since two of these mechanisms - tubular secretion and reabsorption - are saturable processes , they are consequently susceptible to competition between multiple substrates excreted by the kidneys. If two or more medications that are mainly renally excreted are co-administered, they may compete for renal elimination; there is a large likelihood that one agent may "out-compete" or saturate the renal excretion mechanisms before the other concomitantly administered agent(s) are excreted. As a result, the elimination of these other concurrently administered agents may be inhibited or otherwise delayed, which could lead to increases in their serum concentrations and the risk, incidence, and/or severity of adverse effects associated with the exposure to such drugs. The severity of the interaction is minor.

Does Bupropion and Minocycline interact?

•Drug A: Bupropion •Drug B: Minocycline •Severity: MINOR •Description: Minocycline may increase the central nervous system depressant (CNS depressant) activities of Bupropion. •Extended Description: Central nervous system side effects including light-headedness, dizziness, or vertigo have been reported with minocycline intake. This may enhance the effects of central nervous system depressant medications. •Indication (Drug A): Bupropion is indicated for the treatment of major depressive disorder (MDD), seasonal affective disorder (SAD), and as an aid to smoking cessation. When used in combination with naltrexone as the marketed product ContraveⓇ, bupropion is indicated as an adjunct to a reduced-calorie diet and increased physical activity for chronic weight management in adults with an initial body mass index (BMI) of: 30 kg/m^2 or greater (obese) or 27 kg/m^2 or greater (overweight) in the presence of at least one weight-related comorbid condition (e.g., hypertension, type 2 diabetes mellitus, or dyslipidemia). Bupropion is also used off-label as a first-line treatment in patients with ADHD and comorbid bipolar disorder when used as an adjunct to mood stabilizers. •Indication (Drug B): Oral and topical minocycline are indicated to treat inflammatory lesions of acne vulgaris. Subgingival microspheres are indicated as an adjunct treatment in the reduction of pocket depth in adults with periodontitis. Oral and intravenous formulations are indicated to treat infections of susceptible microorganisms. These include rickettsiae, Mycoplasma pneumoniae, Chlamydia trachomatis, Chlamydophila psittaci, Chlamydia trachomatis, Ureaplasma urealyticum, Borrelia recurrentis, Haemophilus ducreyi, Yersinia pestis, Francisella tularensis, Vibrio cholerae, Campylobacter fetus, Brucella species, Bartonella bacilliformis, Klebsiella granulomatis, Escherichia coli, Enterobacter aerogenes, Shigella species, Acinetobacter species, Haemophilus influenzae, and Kelbsiella species. •Pharmacodynamics (Drug A): Bupropion is chemically unrelated to tricyclic, tetracyclic, selective serotonin re-uptake inhibitors, or other known antidepressant agents. Compared to classical tricyclic antidepressants, Bupropion is a relatively weak inhibitor of the neuronal uptake of norepinephrine and dopamine. In addition, Bupropion does not inhibit monoamine oxidase. Bupropion has been found to be essentially inactive at the serotonin transporter (SERT)(IC50 >10 000 nM), however both bupropion and its primary metabolite hydroxybupropion have been found to block the function of cation-selective serotonin type 3A receptors (5-HT3ARs). Bupropion produces dose-related central nervous system (CNS) stimulant effects in animals, as evidenced by increased locomotor activity, increased rates of responding in various schedule-controlled operant behaviour tasks, and, at high doses, induction of mild stereotyped behaviour. Due to these stimulant effects and selective activity at dopamine and norepinephrine receptors, bupropion has been identified as having an abuse potential. Bupropion has a similar structure to the controlled substance Cathinone, and has been identified as having mild amphetamine-like activity, particularly when inhaled or injected. Bupropion is also known to lower the seizure threshold, making any pre-existing seizure conditions a contraindication to its use. This risk is exacerbated when bupropion is combined with other drugs or substances that lower the seizure threshold, such as cocaine, or in clinical situations that would increase the risk of a seizure such as abrupt alcohol or benzodiazepine withdrawal. As norepinephrine has been shown to have anticonvulsant properties, bupropion's inhibitory effects on NET are thought to contribute to its pro-convulsant activity. Bupropion has been shown to increase blood pressure and pose a risk for exacerbation of unmanaged or pre-existing hypertension, however, clinical trials of bupropion in smokers with CVD have not identified an increased incidence of CV events including stroke or heart attack. In clinical trials, the mean increase in systolic blood pressure associated with the use of bupropion was found to be 1.3 mmHg. •Pharmacodynamics (Drug B): Minocycline is a tetracycline antibiotic that binds to the bacterial 30S ribosomal subunit and interferes with protein synthesis. It is generally given 2-4 times daily, so the duration of action is short. Intravenous minocycline should not exceed 400mg in 24 hours. Patients should be counselled regarding the risks related to tooth and bone development, pseudomembranous colitis, central nervous system side effects, and pseudotumor cerebri. •Mechanism of action (Drug A): Bupropion is a norepinephrine/dopamine-reuptake inhibitor (NDRI) that exerts its pharmacological effects by weakly inhibiting the enzymes involved in the uptake of the neurotransmitters norepinephrine and dopamine from the synaptic cleft, therefore prolonging their duration of action within the neuronal synapse and the downstream effects of these neurotransmitters. More specifically, bupropion binds to the norepinephrine transporter (NET) and the dopamine transporter (DAT). Bupropion was originally classified as an "atypical" antidepressant because it does not exert the same effects as the classical antidepressants such as Monoamine Oxidase Inhibitors (MAOIs), Tricyclic Antidepressants (TCAs), or Selective Serotonin Reuptake Inhibitors (SSRIs). While it has comparable effectiveness to typical first-line options for the treatment of depression such as SSRIs, bupropion is a unique option for the treatment of MDD as it lacks any clinically relevant serotonergic effects, typical of other mood medications, or any effects on histamine or adrenaline receptors. Lack of activity at these receptors results in a more tolerable side effect profile; bupropion is less likely to cause sexual side effects, sedation, or weight gain as compared to SSRIs or TCAs, for example. When used as an aid to smoking cessation, bupropion is thought to confer its anti-craving and anti-withdrawal effects by inhibiting dopamine reuptake, which is thought to be involved in the reward pathways associated with nicotine, and through the antagonism of the nicotinic acetylcholinergic receptor (AChR), thereby blunting the effects of nicotine. Furthermore, the stimulatory effects produced by bupropion in the central nervous system are similar to nicotine's effects, making low doses of bupropion a suitable option as a nicotine substitute. When used in combination with naltrexone in the marketed product ContraveⓇ for chronic weight management, the two components are thought to have effects on areas of the brain involved in the regulation of food intake. This includes the hypothalamus, which is involved in appetite regulation, and the mesolimbic dopamine circuit, which is involved in reward pathways. Studies have shown that the combined activity of bupropion and naltrexone increase the firing rate of hypothalamic pro-opiomelanocortin (POMC) neurons and blockade of opioid receptor-mediated POMC auto-inhibition, which are associated with a reduction in food intake and increased energy expenditure. This combination was also found to reduce food intake when injected directly into the ventral tegmental area of the mesolimbic circuit in mice, which is an area associated with the regulation of reward pathways. •Mechanism of action (Drug B): Tetracyclines enter bacterial cells through OmpF and OmpC porins by coordinating with cations like magnesium. This allows tetracyclines into the periplasm where they dissociate, allowing the lipophilic tetracycline to diffuse into the bacterial cytoplasm. Tetracyclines prevent aminoacyl-tRNA from binding to the 30S ribosome, inhibiting protein synthesis. •Absorption (Drug A): Bupropion is currently available in 3 distinct, but bioequivalent formulations: immediate release (IR), sustained-release (SR), and extended-release (XL). Immediate Release Formulation In humans, following oral administration of bupropion hydrochloride tablets, peak plasma bupropion concentrations are usually achieved within 2 hours. IR formulations provide a short duration of action and are therefore generally dosed three times per day. Sustained Release Formulation In humans, following oral administration of bupropion hydrochloride sustained-release tablets (SR), peak plasma concentration (Cmax) of bupropion is usually achieved within 3 hours. SR formulations provide a 12-hour extended release of medication and are therefore generally dosed twice per day. Extended Release Formulation Following single oral administration of bupropion hydrochloride extended-release tablets (XL) to healthy volunteers, the median time to peak plasma concentrations for bupropion was approximately 5 hours. The presence of food did not affect the peak concentration or area under the curve of bupropion. XL formulations provide a 24-hour extended release of medication and are therefore generally dosed once per day/ In a trial comparing chronic dosing with bupropion hydrochloride extended-release tablets (SR) 150 mg twice daily to bupropion immediate-release formulation 100 mg 3 times daily, the steady state Cmax for bupropion after bupropion hydrochloride sustained-release tablets (SR) administration was approximately 85% of those achieved after bupropion immediate-release formulation administration. Exposure (AUC) to bupropion was equivalent for both formulations. Bioequivalence was also demonstrated for all three major active metabolites (i.e., hydroxybupropion, threohydrobupropion and erythrohydrobupropion) for both Cmax and AUC. Thus, at steady state, bupropion hydrochloride sustained-release tablets (SR) given twice daily, and the immediate-release formulation of bupropion given 3 times daily, are essentially bioequivalent for both bupropion and the 3 quantitatively important metabolites. Furthermore, in a study comparing 14-day dosing with bupropion hydrochloride extended-release tablets (XL), 300 mg once-daily to the immediate-release formulation of bupropion at 100 mg 3 times daily, equivalence was demonstrated for peak plasma concentration and area under the curve for bupropion and the three metabolites (hydroxybupropion, threohydrobupropion, and erythrohydrobupropion). Additionally, in a study comparing 14-day dosing with bupropion hydrochloride extended-release tablets (XL) 300 mg once daily to the sustained-release formulation of bupropion at 150 mg 2 times daily, equivalence was demonstrated for peak plasma concentration and area under the curve for bupropion and the three metabolites. Bupropion hydrochloride extended-release tablets (SR) can be taken with or without food. Bupropion Cmax and AUC were increased by 11% to 35% and 16% to 19%, respectively, when bupropion hydrochloride extended-release tablets (SR) was administered with food to healthy volunteers in three trials. The food effect is not considered clinically significant. Following a single-dose administration of bupropion hydrochloride extended-release tablets (SR) in humans, Cmax of bupropion's metabolite hydroxybupropion occurs approximately 6 hours post-dose and is approximately 10 times the peak level of the parent drug at steady state. The elimination half-life of hydroxybupropion is approximately 20 (±5) hours and its AUC at steady state is about 17 times that of bupropion. The times to peak concentrations for the erythrohydrobupropion and threohydrobupropion metabolites are similar to that of the hydroxybupropion metabolite. However, their elimination half-lives are longer, 33(±10) and 37 (±13) hours, respectively, and steady-state AUCs are 1.5 and 7 times that of bupropion, respectively. •Absorption (Drug B): 100mg of oral minocycline reaches a C max of 1.6mg/L, with a T max of 1.9h, and an AUC of 31.6mg/L*h. 200mg of oral minocycline reaches a C max of 3.1mg/L, with a T max of 2.5h, and an AUC of 48.3mg/L*h. •Volume of distribution (Drug A): No volume of distribution available •Volume of distribution (Drug B): The volume of distribution of minocycline has been reported as 67.5-115L. •Protein binding (Drug A): In vitro tests show that bupropion is 84% bound to human plasma proteins at concentrations up to 200 mcg per mL. The extent of protein binding of the hydroxybupropion metabolite is similar to that for bupropion, whereas the extent of protein binding of the threohydrobupropion metabolite is about half that seen with bupropion. •Protein binding (Drug B): Minocycline is 76% protein bound in serum. •Metabolism (Drug A): Bupropion is extensively metabolized in humans. Three metabolites are active: hydroxybupropion, which is formed via hydroxylation of the tert-butyl group of bupropion, and the amino-alcohol isomers, threohydrobupropion and erythrohydrobupropion, which are formed via reduction of the carbonyl group. In vitro findings suggest that CYP2B6 is the principal isoenzyme involved in the formation of hydroxybupropion, while cytochrome P450 enzymes are not involved in the formation of threohydrobupropion. Hydroxybupropion has been shown to have the same affinity as bupropion for the norepinephrine transporter (NET) but approximately 50% of its antidepressant activity despite reaching concentrations of ~10-fold higher than that of the parent drug. Oxidation of the bupropion side chain results in the formation of a glycine conjugate of meta-chlorobenzoic acid, which is then excreted as the major urinary metabolite. The potency and toxicity of the metabolites relative to bupropion have not been fully characterized. However, it has been demonstrated in an antidepressant screening test in mice that hydroxybupropion is one-half as potent as bupropion, while threohydrobupropion and erythrohydrobupropion are 5-fold less potent than bupropion. This may be of clinical importance because the plasma concentrations of the metabolites are as high as or higher than those of bupropion. Bupropion and its metabolites exhibit linear kinetics following chronic administration of 300 to 450 mg per day. •Metabolism (Drug B): Minocycline is primarily metabolized to 9-hydroxyminocycline. It is also metabolized to 2 different N-demethylated metabolites. •Route of elimination (Drug A): Bupropion is extensively metabolized in humans. Oxidation of the bupropion side chain results in the formation of a glycine conjugate of metachlorobenzoic acid, which is then excreted as the major urinary metabolite. Following oral administration of 200 mg of 14C-bupropion in humans, 87% and 10% of the radioactive dose were recovered in the urine and feces, respectively. However, the fraction of the oral dose of bupropion excreted unchanged was only 0.5%, a finding consistent with the extensive metabolism of bupropion. •Route of elimination (Drug B): Minocycline is predominantly eliminated through the biliary route. 4.5-9% of an intravenous minocycline dose is recovered in the urine. 10-19.5% of an oral dose is recovered in the urine and 20-34% is recovered in the feces. •Half-life (Drug A): 24 hours •Half-life (Drug B): The half life of minocycline pellet filled capsules is 11.1-22.1 hours. Minocycline intravenous injections have a half live of 15-23 hours. •Clearance (Drug A): No clearance available •Clearance (Drug B): Intravenous minocycline has a clearance of 3.36-5.7L/h, while oral minocycline has a clearance of 3.42-4.4L/h. •Toxicity (Drug A): Symptoms of overdose include seizures, hallucinations, loss of consciousness, tachycardia, and cardiac arrest. •Toxicity (Drug B): The oral LD 50 in rats is 2380mg/kg and in mice is 3600mg/kg. The intraperitoneal LD 50 in rats is 331mg/kg and in mice is 299mg/kg. The subcutaneous LD 50 in rats is 1700mg/kg and in mice is 2290mg/kg. Patients experiencing an overdose may present with dizziness, nausea, and vomiting. In the event of an overdose, discontinue minocycline and treat patients with symptomatic and supportive measures. •Brand Names (Drug A): Aplenzin, Auvelity, Budeprion, Contrave, Forfivo, Wellbutrin, Zyban •Brand Names (Drug B): Amzeeq, Arestin, Dynacin, Minocin, Minolira, Solodyn, Ximino, Zilxi •Synonyms (Drug A): No synonyms listed •Synonyms (Drug B): Minociclina Minociclinum Minocyclin Minocycline Minocyclinum Minomycin •Summary (Drug A): Bupropion is a norepinephrine and dopamine reuptake inhibitor used in the treatment of major depressive disorder (MDD), seasonal affective disorder (SAD), and as an aid to smoking cessation. •Summary (Drug B): Minocycline is a tetracycline analog used to treat a wide variety of infections in the body.

Central nervous system side effects including light-headedness, dizziness, or vertigo have been reported with minocycline intake. This may enhance the effects of central nervous system depressant medications. The severity of the interaction is minor.

Question: Does Bupropion and Minocycline interact? Information: •Drug A: Bupropion •Drug B: Minocycline •Severity: MINOR •Description: Minocycline may increase the central nervous system depressant (CNS depressant) activities of Bupropion. •Extended Description: Central nervous system side effects including light-headedness, dizziness, or vertigo have been reported with minocycline intake. This may enhance the effects of central nervous system depressant medications. •Indication (Drug A): Bupropion is indicated for the treatment of major depressive disorder (MDD), seasonal affective disorder (SAD), and as an aid to smoking cessation. When used in combination with naltrexone as the marketed product ContraveⓇ, bupropion is indicated as an adjunct to a reduced-calorie diet and increased physical activity for chronic weight management in adults with an initial body mass index (BMI) of: 30 kg/m^2 or greater (obese) or 27 kg/m^2 or greater (overweight) in the presence of at least one weight-related comorbid condition (e.g., hypertension, type 2 diabetes mellitus, or dyslipidemia). Bupropion is also used off-label as a first-line treatment in patients with ADHD and comorbid bipolar disorder when used as an adjunct to mood stabilizers. •Indication (Drug B): Oral and topical minocycline are indicated to treat inflammatory lesions of acne vulgaris. Subgingival microspheres are indicated as an adjunct treatment in the reduction of pocket depth in adults with periodontitis. Oral and intravenous formulations are indicated to treat infections of susceptible microorganisms. These include rickettsiae, Mycoplasma pneumoniae, Chlamydia trachomatis, Chlamydophila psittaci, Chlamydia trachomatis, Ureaplasma urealyticum, Borrelia recurrentis, Haemophilus ducreyi, Yersinia pestis, Francisella tularensis, Vibrio cholerae, Campylobacter fetus, Brucella species, Bartonella bacilliformis, Klebsiella granulomatis, Escherichia coli, Enterobacter aerogenes, Shigella species, Acinetobacter species, Haemophilus influenzae, and Kelbsiella species. •Pharmacodynamics (Drug A): Bupropion is chemically unrelated to tricyclic, tetracyclic, selective serotonin re-uptake inhibitors, or other known antidepressant agents. Compared to classical tricyclic antidepressants, Bupropion is a relatively weak inhibitor of the neuronal uptake of norepinephrine and dopamine. In addition, Bupropion does not inhibit monoamine oxidase. Bupropion has been found to be essentially inactive at the serotonin transporter (SERT)(IC50 >10 000 nM), however both bupropion and its primary metabolite hydroxybupropion have been found to block the function of cation-selective serotonin type 3A receptors (5-HT3ARs). Bupropion produces dose-related central nervous system (CNS) stimulant effects in animals, as evidenced by increased locomotor activity, increased rates of responding in various schedule-controlled operant behaviour tasks, and, at high doses, induction of mild stereotyped behaviour. Due to these stimulant effects and selective activity at dopamine and norepinephrine receptors, bupropion has been identified as having an abuse potential. Bupropion has a similar structure to the controlled substance Cathinone, and has been identified as having mild amphetamine-like activity, particularly when inhaled or injected. Bupropion is also known to lower the seizure threshold, making any pre-existing seizure conditions a contraindication to its use. This risk is exacerbated when bupropion is combined with other drugs or substances that lower the seizure threshold, such as cocaine, or in clinical situations that would increase the risk of a seizure such as abrupt alcohol or benzodiazepine withdrawal. As norepinephrine has been shown to have anticonvulsant properties, bupropion's inhibitory effects on NET are thought to contribute to its pro-convulsant activity. Bupropion has been shown to increase blood pressure and pose a risk for exacerbation of unmanaged or pre-existing hypertension, however, clinical trials of bupropion in smokers with CVD have not identified an increased incidence of CV events including stroke or heart attack. In clinical trials, the mean increase in systolic blood pressure associated with the use of bupropion was found to be 1.3 mmHg. •Pharmacodynamics (Drug B): Minocycline is a tetracycline antibiotic that binds to the bacterial 30S ribosomal subunit and interferes with protein synthesis. It is generally given 2-4 times daily, so the duration of action is short. Intravenous minocycline should not exceed 400mg in 24 hours. Patients should be counselled regarding the risks related to tooth and bone development, pseudomembranous colitis, central nervous system side effects, and pseudotumor cerebri. •Mechanism of action (Drug A): Bupropion is a norepinephrine/dopamine-reuptake inhibitor (NDRI) that exerts its pharmacological effects by weakly inhibiting the enzymes involved in the uptake of the neurotransmitters norepinephrine and dopamine from the synaptic cleft, therefore prolonging their duration of action within the neuronal synapse and the downstream effects of these neurotransmitters. More specifically, bupropion binds to the norepinephrine transporter (NET) and the dopamine transporter (DAT). Bupropion was originally classified as an "atypical" antidepressant because it does not exert the same effects as the classical antidepressants such as Monoamine Oxidase Inhibitors (MAOIs), Tricyclic Antidepressants (TCAs), or Selective Serotonin Reuptake Inhibitors (SSRIs). While it has comparable effectiveness to typical first-line options for the treatment of depression such as SSRIs, bupropion is a unique option for the treatment of MDD as it lacks any clinically relevant serotonergic effects, typical of other mood medications, or any effects on histamine or adrenaline receptors. Lack of activity at these receptors results in a more tolerable side effect profile; bupropion is less likely to cause sexual side effects, sedation, or weight gain as compared to SSRIs or TCAs, for example. When used as an aid to smoking cessation, bupropion is thought to confer its anti-craving and anti-withdrawal effects by inhibiting dopamine reuptake, which is thought to be involved in the reward pathways associated with nicotine, and through the antagonism of the nicotinic acetylcholinergic receptor (AChR), thereby blunting the effects of nicotine. Furthermore, the stimulatory effects produced by bupropion in the central nervous system are similar to nicotine's effects, making low doses of bupropion a suitable option as a nicotine substitute. When used in combination with naltrexone in the marketed product ContraveⓇ for chronic weight management, the two components are thought to have effects on areas of the brain involved in the regulation of food intake. This includes the hypothalamus, which is involved in appetite regulation, and the mesolimbic dopamine circuit, which is involved in reward pathways. Studies have shown that the combined activity of bupropion and naltrexone increase the firing rate of hypothalamic pro-opiomelanocortin (POMC) neurons and blockade of opioid receptor-mediated POMC auto-inhibition, which are associated with a reduction in food intake and increased energy expenditure. This combination was also found to reduce food intake when injected directly into the ventral tegmental area of the mesolimbic circuit in mice, which is an area associated with the regulation of reward pathways. •Mechanism of action (Drug B): Tetracyclines enter bacterial cells through OmpF and OmpC porins by coordinating with cations like magnesium. This allows tetracyclines into the periplasm where they dissociate, allowing the lipophilic tetracycline to diffuse into the bacterial cytoplasm. Tetracyclines prevent aminoacyl-tRNA from binding to the 30S ribosome, inhibiting protein synthesis. •Absorption (Drug A): Bupropion is currently available in 3 distinct, but bioequivalent formulations: immediate release (IR), sustained-release (SR), and extended-release (XL). Immediate Release Formulation In humans, following oral administration of bupropion hydrochloride tablets, peak plasma bupropion concentrations are usually achieved within 2 hours. IR formulations provide a short duration of action and are therefore generally dosed three times per day. Sustained Release Formulation In humans, following oral administration of bupropion hydrochloride sustained-release tablets (SR), peak plasma concentration (Cmax) of bupropion is usually achieved within 3 hours. SR formulations provide a 12-hour extended release of medication and are therefore generally dosed twice per day. Extended Release Formulation Following single oral administration of bupropion hydrochloride extended-release tablets (XL) to healthy volunteers, the median time to peak plasma concentrations for bupropion was approximately 5 hours. The presence of food did not affect the peak concentration or area under the curve of bupropion. XL formulations provide a 24-hour extended release of medication and are therefore generally dosed once per day/ In a trial comparing chronic dosing with bupropion hydrochloride extended-release tablets (SR) 150 mg twice daily to bupropion immediate-release formulation 100 mg 3 times daily, the steady state Cmax for bupropion after bupropion hydrochloride sustained-release tablets (SR) administration was approximately 85% of those achieved after bupropion immediate-release formulation administration. Exposure (AUC) to bupropion was equivalent for both formulations. Bioequivalence was also demonstrated for all three major active metabolites (i.e., hydroxybupropion, threohydrobupropion and erythrohydrobupropion) for both Cmax and AUC. Thus, at steady state, bupropion hydrochloride sustained-release tablets (SR) given twice daily, and the immediate-release formulation of bupropion given 3 times daily, are essentially bioequivalent for both bupropion and the 3 quantitatively important metabolites. Furthermore, in a study comparing 14-day dosing with bupropion hydrochloride extended-release tablets (XL), 300 mg once-daily to the immediate-release formulation of bupropion at 100 mg 3 times daily, equivalence was demonstrated for peak plasma concentration and area under the curve for bupropion and the three metabolites (hydroxybupropion, threohydrobupropion, and erythrohydrobupropion). Additionally, in a study comparing 14-day dosing with bupropion hydrochloride extended-release tablets (XL) 300 mg once daily to the sustained-release formulation of bupropion at 150 mg 2 times daily, equivalence was demonstrated for peak plasma concentration and area under the curve for bupropion and the three metabolites. Bupropion hydrochloride extended-release tablets (SR) can be taken with or without food. Bupropion Cmax and AUC were increased by 11% to 35% and 16% to 19%, respectively, when bupropion hydrochloride extended-release tablets (SR) was administered with food to healthy volunteers in three trials. The food effect is not considered clinically significant. Following a single-dose administration of bupropion hydrochloride extended-release tablets (SR) in humans, Cmax of bupropion's metabolite hydroxybupropion occurs approximately 6 hours post-dose and is approximately 10 times the peak level of the parent drug at steady state. The elimination half-life of hydroxybupropion is approximately 20 (±5) hours and its AUC at steady state is about 17 times that of bupropion. The times to peak concentrations for the erythrohydrobupropion and threohydrobupropion metabolites are similar to that of the hydroxybupropion metabolite. However, their elimination half-lives are longer, 33(±10) and 37 (±13) hours, respectively, and steady-state AUCs are 1.5 and 7 times that of bupropion, respectively. •Absorption (Drug B): 100mg of oral minocycline reaches a C max of 1.6mg/L, with a T max of 1.9h, and an AUC of 31.6mg/L*h. 200mg of oral minocycline reaches a C max of 3.1mg/L, with a T max of 2.5h, and an AUC of 48.3mg/L*h. •Volume of distribution (Drug A): No volume of distribution available •Volume of distribution (Drug B): The volume of distribution of minocycline has been reported as 67.5-115L. •Protein binding (Drug A): In vitro tests show that bupropion is 84% bound to human plasma proteins at concentrations up to 200 mcg per mL. The extent of protein binding of the hydroxybupropion metabolite is similar to that for bupropion, whereas the extent of protein binding of the threohydrobupropion metabolite is about half that seen with bupropion. •Protein binding (Drug B): Minocycline is 76% protein bound in serum. •Metabolism (Drug A): Bupropion is extensively metabolized in humans. Three metabolites are active: hydroxybupropion, which is formed via hydroxylation of the tert-butyl group of bupropion, and the amino-alcohol isomers, threohydrobupropion and erythrohydrobupropion, which are formed via reduction of the carbonyl group. In vitro findings suggest that CYP2B6 is the principal isoenzyme involved in the formation of hydroxybupropion, while cytochrome P450 enzymes are not involved in the formation of threohydrobupropion. Hydroxybupropion has been shown to have the same affinity as bupropion for the norepinephrine transporter (NET) but approximately 50% of its antidepressant activity despite reaching concentrations of ~10-fold higher than that of the parent drug. Oxidation of the bupropion side chain results in the formation of a glycine conjugate of meta-chlorobenzoic acid, which is then excreted as the major urinary metabolite. The potency and toxicity of the metabolites relative to bupropion have not been fully characterized. However, it has been demonstrated in an antidepressant screening test in mice that hydroxybupropion is one-half as potent as bupropion, while threohydrobupropion and erythrohydrobupropion are 5-fold less potent than bupropion. This may be of clinical importance because the plasma concentrations of the metabolites are as high as or higher than those of bupropion. Bupropion and its metabolites exhibit linear kinetics following chronic administration of 300 to 450 mg per day. •Metabolism (Drug B): Minocycline is primarily metabolized to 9-hydroxyminocycline. It is also metabolized to 2 different N-demethylated metabolites. •Route of elimination (Drug A): Bupropion is extensively metabolized in humans. Oxidation of the bupropion side chain results in the formation of a glycine conjugate of metachlorobenzoic acid, which is then excreted as the major urinary metabolite. Following oral administration of 200 mg of 14C-bupropion in humans, 87% and 10% of the radioactive dose were recovered in the urine and feces, respectively. However, the fraction of the oral dose of bupropion excreted unchanged was only 0.5%, a finding consistent with the extensive metabolism of bupropion. •Route of elimination (Drug B): Minocycline is predominantly eliminated through the biliary route. 4.5-9% of an intravenous minocycline dose is recovered in the urine. 10-19.5% of an oral dose is recovered in the urine and 20-34% is recovered in the feces. •Half-life (Drug A): 24 hours •Half-life (Drug B): The half life of minocycline pellet filled capsules is 11.1-22.1 hours. Minocycline intravenous injections have a half live of 15-23 hours. •Clearance (Drug A): No clearance available •Clearance (Drug B): Intravenous minocycline has a clearance of 3.36-5.7L/h, while oral minocycline has a clearance of 3.42-4.4L/h. •Toxicity (Drug A): Symptoms of overdose include seizures, hallucinations, loss of consciousness, tachycardia, and cardiac arrest. •Toxicity (Drug B): The oral LD 50 in rats is 2380mg/kg and in mice is 3600mg/kg. The intraperitoneal LD 50 in rats is 331mg/kg and in mice is 299mg/kg. The subcutaneous LD 50 in rats is 1700mg/kg and in mice is 2290mg/kg. Patients experiencing an overdose may present with dizziness, nausea, and vomiting. In the event of an overdose, discontinue minocycline and treat patients with symptomatic and supportive measures. •Brand Names (Drug A): Aplenzin, Auvelity, Budeprion, Contrave, Forfivo, Wellbutrin, Zyban •Brand Names (Drug B): Amzeeq, Arestin, Dynacin, Minocin, Minolira, Solodyn, Ximino, Zilxi •Synonyms (Drug A): No synonyms listed •Synonyms (Drug B): Minociclina Minociclinum Minocyclin Minocycline Minocyclinum Minomycin •Summary (Drug A): Bupropion is a norepinephrine and dopamine reuptake inhibitor used in the treatment of major depressive disorder (MDD), seasonal affective disorder (SAD), and as an aid to smoking cessation. •Summary (Drug B): Minocycline is a tetracycline analog used to treat a wide variety of infections in the body. Output: Central nervous system side effects including light-headedness, dizziness, or vertigo have been reported with minocycline intake. This may enhance the effects of central nervous system depressant medications. The severity of the interaction is minor.

Does Bupropion and Mirabegron interact?

•Drug A: Bupropion •Drug B: Mirabegron •Severity: MAJOR •Description: The metabolism of Mirabegron can be decreased when combined with Bupropion. •Extended Description: The subject drug is a strong CYP2D6 inhibitor and the affected drug is metabolized by CYP2D6. Concomitant administration may decrease the metabolism of the affected drug, which could increase serum concentrations as well as the risk and severity of adverse effects. •Indication (Drug A): Bupropion is indicated for the treatment of major depressive disorder (MDD), seasonal affective disorder (SAD), and as an aid to smoking cessation. When used in combination with naltrexone as the marketed product ContraveⓇ, bupropion is indicated as an adjunct to a reduced-calorie diet and increased physical activity for chronic weight management in adults with an initial body mass index (BMI) of: 30 kg/m^2 or greater (obese) or 27 kg/m^2 or greater (overweight) in the presence of at least one weight-related comorbid condition (e.g., hypertension, type 2 diabetes mellitus, or dyslipidemia). Bupropion is also used off-label as a first-line treatment in patients with ADHD and comorbid bipolar disorder when used as an adjunct to mood stabilizers. •Indication (Drug B): Mirabegron is indicated for the treatment of overactive bladder (OAB) - with symptoms of urge urinary incontinence, urgency, and urinary frequency - either alone or in combination with solifenacin. It is also indicated for the treatment of neurogenic detrusor overactivity (NDO) in pediatric patients 3 years of age and older and weighing 35kg or more. •Pharmacodynamics (Drug A): Bupropion is chemically unrelated to tricyclic, tetracyclic, selective serotonin re-uptake inhibitors, or other known antidepressant agents. Compared to classical tricyclic antidepressants, Bupropion is a relatively weak inhibitor of the neuronal uptake of norepinephrine and dopamine. In addition, Bupropion does not inhibit monoamine oxidase. Bupropion has been found to be essentially inactive at the serotonin transporter (SERT)(IC50 >10 000 nM), however both bupropion and its primary metabolite hydroxybupropion have been found to block the function of cation-selective serotonin type 3A receptors (5-HT3ARs). Bupropion produces dose-related central nervous system (CNS) stimulant effects in animals, as evidenced by increased locomotor activity, increased rates of responding in various schedule-controlled operant behaviour tasks, and, at high doses, induction of mild stereotyped behaviour. Due to these stimulant effects and selective activity at dopamine and norepinephrine receptors, bupropion has been identified as having an abuse potential. Bupropion has a similar structure to the controlled substance Cathinone, and has been identified as having mild amphetamine-like activity, particularly when inhaled or injected. Bupropion is also known to lower the seizure threshold, making any pre-existing seizure conditions a contraindication to its use. This risk is exacerbated when bupropion is combined with other drugs or substances that lower the seizure threshold, such as cocaine, or in clinical situations that would increase the risk of a seizure such as abrupt alcohol or benzodiazepine withdrawal. As norepinephrine has been shown to have anticonvulsant properties, bupropion's inhibitory effects on NET are thought to contribute to its pro-convulsant activity. Bupropion has been shown to increase blood pressure and pose a risk for exacerbation of unmanaged or pre-existing hypertension, however, clinical trials of bupropion in smokers with CVD have not identified an increased incidence of CV events including stroke or heart attack. In clinical trials, the mean increase in systolic blood pressure associated with the use of bupropion was found to be 1.3 mmHg. •Pharmacodynamics (Drug B): Mirabegron exerts its pharmacologic effects by forcing bladder smooth muscle to relax, thereby expanding its capacity and relieving urgency. Mirabegron does not appear to adversely affect the mean maximum flow rate or mean detrusor pressure at maximum flow rate in patients with lower urinary tract symptoms and bladder outlet obstruction (BOO), but should be used with in patients with BOO due to reports of significant urinary retention. Furthermore, mirabegron increases both blood pressure and heart rate in a dose-dependent manner and should therefore be used with caution in patients with severely uncontrolled hypertension or others for whom these increases may prove dangerous. •Mechanism of action (Drug A): Bupropion is a norepinephrine/dopamine-reuptake inhibitor (NDRI) that exerts its pharmacological effects by weakly inhibiting the enzymes involved in the uptake of the neurotransmitters norepinephrine and dopamine from the synaptic cleft, therefore prolonging their duration of action within the neuronal synapse and the downstream effects of these neurotransmitters. More specifically, bupropion binds to the norepinephrine transporter (NET) and the dopamine transporter (DAT). Bupropion was originally classified as an "atypical" antidepressant because it does not exert the same effects as the classical antidepressants such as Monoamine Oxidase Inhibitors (MAOIs), Tricyclic Antidepressants (TCAs), or Selective Serotonin Reuptake Inhibitors (SSRIs). While it has comparable effectiveness to typical first-line options for the treatment of depression such as SSRIs, bupropion is a unique option for the treatment of MDD as it lacks any clinically relevant serotonergic effects, typical of other mood medications, or any effects on histamine or adrenaline receptors. Lack of activity at these receptors results in a more tolerable side effect profile; bupropion is less likely to cause sexual side effects, sedation, or weight gain as compared to SSRIs or TCAs, for example. When used as an aid to smoking cessation, bupropion is thought to confer its anti-craving and anti-withdrawal effects by inhibiting dopamine reuptake, which is thought to be involved in the reward pathways associated with nicotine, and through the antagonism of the nicotinic acetylcholinergic receptor (AChR), thereby blunting the effects of nicotine. Furthermore, the stimulatory effects produced by bupropion in the central nervous system are similar to nicotine's effects, making low doses of bupropion a suitable option as a nicotine substitute. When used in combination with naltrexone in the marketed product ContraveⓇ for chronic weight management, the two components are thought to have effects on areas of the brain involved in the regulation of food intake. This includes the hypothalamus, which is involved in appetite regulation, and the mesolimbic dopamine circuit, which is involved in reward pathways. Studies have shown that the combined activity of bupropion and naltrexone increase the firing rate of hypothalamic pro-opiomelanocortin (POMC) neurons and blockade of opioid receptor-mediated POMC auto-inhibition, which are associated with a reduction in food intake and increased energy expenditure. This combination was also found to reduce food intake when injected directly into the ventral tegmental area of the mesolimbic circuit in mice, which is an area associated with the regulation of reward pathways. •Mechanism of action (Drug B): Mirabegron is a potent and selective agonist of beta-3 adrenergic receptors. The activation of beta-3 receptors relaxes detrusor smooth muscle during the storage phase of the urinary bladder fill-void cycle, which increases the bladder's storage capacity thereby alleviating feelings of urgency and frequency. •Absorption (Drug A): Bupropion is currently available in 3 distinct, but bioequivalent formulations: immediate release (IR), sustained-release (SR), and extended-release (XL). Immediate Release Formulation In humans, following oral administration of bupropion hydrochloride tablets, peak plasma bupropion concentrations are usually achieved within 2 hours. IR formulations provide a short duration of action and are therefore generally dosed three times per day. Sustained Release Formulation In humans, following oral administration of bupropion hydrochloride sustained-release tablets (SR), peak plasma concentration (Cmax) of bupropion is usually achieved within 3 hours. SR formulations provide a 12-hour extended release of medication and are therefore generally dosed twice per day. Extended Release Formulation Following single oral administration of bupropion hydrochloride extended-release tablets (XL) to healthy volunteers, the median time to peak plasma concentrations for bupropion was approximately 5 hours. The presence of food did not affect the peak concentration or area under the curve of bupropion. XL formulations provide a 24-hour extended release of medication and are therefore generally dosed once per day/ In a trial comparing chronic dosing with bupropion hydrochloride extended-release tablets (SR) 150 mg twice daily to bupropion immediate-release formulation 100 mg 3 times daily, the steady state Cmax for bupropion after bupropion hydrochloride sustained-release tablets (SR) administration was approximately 85% of those achieved after bupropion immediate-release formulation administration. Exposure (AUC) to bupropion was equivalent for both formulations. Bioequivalence was also demonstrated for all three major active metabolites (i.e., hydroxybupropion, threohydrobupropion and erythrohydrobupropion) for both Cmax and AUC. Thus, at steady state, bupropion hydrochloride sustained-release tablets (SR) given twice daily, and the immediate-release formulation of bupropion given 3 times daily, are essentially bioequivalent for both bupropion and the 3 quantitatively important metabolites. Furthermore, in a study comparing 14-day dosing with bupropion hydrochloride extended-release tablets (XL), 300 mg once-daily to the immediate-release formulation of bupropion at 100 mg 3 times daily, equivalence was demonstrated for peak plasma concentration and area under the curve for bupropion and the three metabolites (hydroxybupropion, threohydrobupropion, and erythrohydrobupropion). Additionally, in a study comparing 14-day dosing with bupropion hydrochloride extended-release tablets (XL) 300 mg once daily to the sustained-release formulation of bupropion at 150 mg 2 times daily, equivalence was demonstrated for peak plasma concentration and area under the curve for bupropion and the three metabolites. Bupropion hydrochloride extended-release tablets (SR) can be taken with or without food. Bupropion Cmax and AUC were increased by 11% to 35% and 16% to 19%, respectively, when bupropion hydrochloride extended-release tablets (SR) was administered with food to healthy volunteers in three trials. The food effect is not considered clinically significant. Following a single-dose administration of bupropion hydrochloride extended-release tablets (SR) in humans, Cmax of bupropion's metabolite hydroxybupropion occurs approximately 6 hours post-dose and is approximately 10 times the peak level of the parent drug at steady state. The elimination half-life of hydroxybupropion is approximately 20 (±5) hours and its AUC at steady state is about 17 times that of bupropion. The times to peak concentrations for the erythrohydrobupropion and threohydrobupropion metabolites are similar to that of the hydroxybupropion metabolite. However, their elimination half-lives are longer, 33(±10) and 37 (±13) hours, respectively, and steady-state AUCs are 1.5 and 7 times that of bupropion, respectively. •Absorption (Drug B): The absolute bioavailability of orally administered mirabegron ranges from 29% at a dose of 25 mg to 35% at a dose of 50 mg. The T max for the extended-release tablet and suspension formulations are approximately 3.5 hours, while the T max for the granule formulation is 4-5 hours. Both C max and AUC increase more than dose proportionally - an increase in dose from 50mg to 100mg results in a 2.9- and 2.6-fold increase in C max and AUC, respectively, whereas an increase from 50mg to 200mg results in a 8.4- and 6.5-fold increase in C max and AUC, respectively. Steady-state concentrations of mirabegron are achieved after approximately 7 days of once-daily administration. •Volume of distribution (Drug A): No volume of distribution available •Volume of distribution (Drug B): Following intravenous administration, mirabegron has an apparent steady-state volume of distribution (Vd) of 1670 L indicating extensive distribution. •Protein binding (Drug A): In vitro tests show that bupropion is 84% bound to human plasma proteins at concentrations up to 200 mcg per mL. The extent of protein binding of the hydroxybupropion metabolite is similar to that for bupropion, whereas the extent of protein binding of the threohydrobupropion metabolite is about half that seen with bupropion. •Protein binding (Drug B): Mirabegron is approximately 71% protein-bound in plasma, primarily to albumin and alpha-1-acid glycoprotein. •Metabolism (Drug A): Bupropion is extensively metabolized in humans. Three metabolites are active: hydroxybupropion, which is formed via hydroxylation of the tert-butyl group of bupropion, and the amino-alcohol isomers, threohydrobupropion and erythrohydrobupropion, which are formed via reduction of the carbonyl group. In vitro findings suggest that CYP2B6 is the principal isoenzyme involved in the formation of hydroxybupropion, while cytochrome P450 enzymes are not involved in the formation of threohydrobupropion. Hydroxybupropion has been shown to have the same affinity as bupropion for the norepinephrine transporter (NET) but approximately 50% of its antidepressant activity despite reaching concentrations of ~10-fold higher than that of the parent drug. Oxidation of the bupropion side chain results in the formation of a glycine conjugate of meta-chlorobenzoic acid, which is then excreted as the major urinary metabolite. The potency and toxicity of the metabolites relative to bupropion have not been fully characterized. However, it has been demonstrated in an antidepressant screening test in mice that hydroxybupropion is one-half as potent as bupropion, while threohydrobupropion and erythrohydrobupropion are 5-fold less potent than bupropion. This may be of clinical importance because the plasma concentrations of the metabolites are as high as or higher than those of bupropion. Bupropion and its metabolites exhibit linear kinetics following chronic administration of 300 to 450 mg per day. •Metabolism (Drug B): Mirabegron is extensively metabolized via a number of mechanisms, although unchanged parent drug is still the major circulating component following oral administration. Presumed metabolic pathways and their resultant metabolites include amide hydrolysis (M5, M16, M17), glucuronidation (mirabegron O-glucuronide, N-glucuronide, N-carbamoylglucuronide, M12), and secondary amine oxidation or dealkylation (M8, M9, M15), amongst others. The enzymes responsible for the oxidative metabolism of mirabegron are thought to be CYP3A4 and CYP2D6, while the UDP-glucuronosyltransferases responsible for conjugation reactions have been identified as UGT2B7, UGT1A3, and UGT1A8. Other enzymes that may be involved in the metabolism of mirabegron include butylcholinesterase and possibly alcohol dehydrogenase. •Route of elimination (Drug A): Bupropion is extensively metabolized in humans. Oxidation of the bupropion side chain results in the formation of a glycine conjugate of metachlorobenzoic acid, which is then excreted as the major urinary metabolite. Following oral administration of 200 mg of 14C-bupropion in humans, 87% and 10% of the radioactive dose were recovered in the urine and feces, respectively. However, the fraction of the oral dose of bupropion excreted unchanged was only 0.5%, a finding consistent with the extensive metabolism of bupropion. •Route of elimination (Drug B): Of a 160mg radiolabeled dose administered to healthy volunteers, approximately 55% of the radioactivity was recovered in the urine and 34% in the feces. Approximately 25% of unchanged mirabegron was recovered in the urine while 0% was recovered in the feces. Renal elimination is achieved primarily via active tubular secretion with some contribution by glomerular filtration. •Half-life (Drug A): 24 hours •Half-life (Drug B): The mean terminal elimination half-life of mirabegron in adults being treated for overactive bladder is approximately 50 hours. In pediatric patients receiving the granule formulation for the treatment of neurogenic detrusor overactivity, the mean terminal elimination half-life is approximately 26-31 hours. •Clearance (Drug A): No clearance available •Clearance (Drug B): Total plasma clearance following intravenous administration is approximately 57 L/h, with renal clearance accounting for roughly 25% at approximately 13 L/h. •Toxicity (Drug A): Symptoms of overdose include seizures, hallucinations, loss of consciousness, tachycardia, and cardiac arrest. •Toxicity (Drug B): At doses of up to 400mg in healthy volunteers (~8x the recommended maximum), reported symptoms of overdose included palpitations and increased heart rate. Symptoms of chronic overdosage are similar in presentation and may also include a rise in systolic blood pressure. In cases of overdosage, employ standard symptomatic and supportive measures in addition to ECG monitoring. •Brand Names (Drug A): Aplenzin, Auvelity, Budeprion, Contrave, Forfivo, Wellbutrin, Zyban •Brand Names (Drug B): Myrbetriq •Synonyms (Drug A): No synonyms listed •Synonyms (Drug B): No synonyms listed •Summary (Drug A): Bupropion is a norepinephrine and dopamine reuptake inhibitor used in the treatment of major depressive disorder (MDD), seasonal affective disorder (SAD), and as an aid to smoking cessation. •Summary (Drug B): Mirabegron is a beta-3 adrenergic agonist used to treat overactive bladder and neurogenic detrusor overactivity.

The subject drug is a strong CYP2D6 inhibitor and the affected drug is metabolized by CYP2D6. Concomitant administration may decrease the metabolism of the affected drug, which could increase serum concentrations as well as the risk and severity of adverse effects. The severity of the interaction is major.

Question: Does Bupropion and Mirabegron interact? Information: •Drug A: Bupropion •Drug B: Mirabegron •Severity: MAJOR •Description: The metabolism of Mirabegron can be decreased when combined with Bupropion. •Extended Description: The subject drug is a strong CYP2D6 inhibitor and the affected drug is metabolized by CYP2D6. Concomitant administration may decrease the metabolism of the affected drug, which could increase serum concentrations as well as the risk and severity of adverse effects. •Indication (Drug A): Bupropion is indicated for the treatment of major depressive disorder (MDD), seasonal affective disorder (SAD), and as an aid to smoking cessation. When used in combination with naltrexone as the marketed product ContraveⓇ, bupropion is indicated as an adjunct to a reduced-calorie diet and increased physical activity for chronic weight management in adults with an initial body mass index (BMI) of: 30 kg/m^2 or greater (obese) or 27 kg/m^2 or greater (overweight) in the presence of at least one weight-related comorbid condition (e.g., hypertension, type 2 diabetes mellitus, or dyslipidemia). Bupropion is also used off-label as a first-line treatment in patients with ADHD and comorbid bipolar disorder when used as an adjunct to mood stabilizers. •Indication (Drug B): Mirabegron is indicated for the treatment of overactive bladder (OAB) - with symptoms of urge urinary incontinence, urgency, and urinary frequency - either alone or in combination with solifenacin. It is also indicated for the treatment of neurogenic detrusor overactivity (NDO) in pediatric patients 3 years of age and older and weighing 35kg or more. •Pharmacodynamics (Drug A): Bupropion is chemically unrelated to tricyclic, tetracyclic, selective serotonin re-uptake inhibitors, or other known antidepressant agents. Compared to classical tricyclic antidepressants, Bupropion is a relatively weak inhibitor of the neuronal uptake of norepinephrine and dopamine. In addition, Bupropion does not inhibit monoamine oxidase. Bupropion has been found to be essentially inactive at the serotonin transporter (SERT)(IC50 >10 000 nM), however both bupropion and its primary metabolite hydroxybupropion have been found to block the function of cation-selective serotonin type 3A receptors (5-HT3ARs). Bupropion produces dose-related central nervous system (CNS) stimulant effects in animals, as evidenced by increased locomotor activity, increased rates of responding in various schedule-controlled operant behaviour tasks, and, at high doses, induction of mild stereotyped behaviour. Due to these stimulant effects and selective activity at dopamine and norepinephrine receptors, bupropion has been identified as having an abuse potential. Bupropion has a similar structure to the controlled substance Cathinone, and has been identified as having mild amphetamine-like activity, particularly when inhaled or injected. Bupropion is also known to lower the seizure threshold, making any pre-existing seizure conditions a contraindication to its use. This risk is exacerbated when bupropion is combined with other drugs or substances that lower the seizure threshold, such as cocaine, or in clinical situations that would increase the risk of a seizure such as abrupt alcohol or benzodiazepine withdrawal. As norepinephrine has been shown to have anticonvulsant properties, bupropion's inhibitory effects on NET are thought to contribute to its pro-convulsant activity. Bupropion has been shown to increase blood pressure and pose a risk for exacerbation of unmanaged or pre-existing hypertension, however, clinical trials of bupropion in smokers with CVD have not identified an increased incidence of CV events including stroke or heart attack. In clinical trials, the mean increase in systolic blood pressure associated with the use of bupropion was found to be 1.3 mmHg. •Pharmacodynamics (Drug B): Mirabegron exerts its pharmacologic effects by forcing bladder smooth muscle to relax, thereby expanding its capacity and relieving urgency. Mirabegron does not appear to adversely affect the mean maximum flow rate or mean detrusor pressure at maximum flow rate in patients with lower urinary tract symptoms and bladder outlet obstruction (BOO), but should be used with in patients with BOO due to reports of significant urinary retention. Furthermore, mirabegron increases both blood pressure and heart rate in a dose-dependent manner and should therefore be used with caution in patients with severely uncontrolled hypertension or others for whom these increases may prove dangerous. •Mechanism of action (Drug A): Bupropion is a norepinephrine/dopamine-reuptake inhibitor (NDRI) that exerts its pharmacological effects by weakly inhibiting the enzymes involved in the uptake of the neurotransmitters norepinephrine and dopamine from the synaptic cleft, therefore prolonging their duration of action within the neuronal synapse and the downstream effects of these neurotransmitters. More specifically, bupropion binds to the norepinephrine transporter (NET) and the dopamine transporter (DAT). Bupropion was originally classified as an "atypical" antidepressant because it does not exert the same effects as the classical antidepressants such as Monoamine Oxidase Inhibitors (MAOIs), Tricyclic Antidepressants (TCAs), or Selective Serotonin Reuptake Inhibitors (SSRIs). While it has comparable effectiveness to typical first-line options for the treatment of depression such as SSRIs, bupropion is a unique option for the treatment of MDD as it lacks any clinically relevant serotonergic effects, typical of other mood medications, or any effects on histamine or adrenaline receptors. Lack of activity at these receptors results in a more tolerable side effect profile; bupropion is less likely to cause sexual side effects, sedation, or weight gain as compared to SSRIs or TCAs, for example. When used as an aid to smoking cessation, bupropion is thought to confer its anti-craving and anti-withdrawal effects by inhibiting dopamine reuptake, which is thought to be involved in the reward pathways associated with nicotine, and through the antagonism of the nicotinic acetylcholinergic receptor (AChR), thereby blunting the effects of nicotine. Furthermore, the stimulatory effects produced by bupropion in the central nervous system are similar to nicotine's effects, making low doses of bupropion a suitable option as a nicotine substitute. When used in combination with naltrexone in the marketed product ContraveⓇ for chronic weight management, the two components are thought to have effects on areas of the brain involved in the regulation of food intake. This includes the hypothalamus, which is involved in appetite regulation, and the mesolimbic dopamine circuit, which is involved in reward pathways. Studies have shown that the combined activity of bupropion and naltrexone increase the firing rate of hypothalamic pro-opiomelanocortin (POMC) neurons and blockade of opioid receptor-mediated POMC auto-inhibition, which are associated with a reduction in food intake and increased energy expenditure. This combination was also found to reduce food intake when injected directly into the ventral tegmental area of the mesolimbic circuit in mice, which is an area associated with the regulation of reward pathways. •Mechanism of action (Drug B): Mirabegron is a potent and selective agonist of beta-3 adrenergic receptors. The activation of beta-3 receptors relaxes detrusor smooth muscle during the storage phase of the urinary bladder fill-void cycle, which increases the bladder's storage capacity thereby alleviating feelings of urgency and frequency. •Absorption (Drug A): Bupropion is currently available in 3 distinct, but bioequivalent formulations: immediate release (IR), sustained-release (SR), and extended-release (XL). Immediate Release Formulation In humans, following oral administration of bupropion hydrochloride tablets, peak plasma bupropion concentrations are usually achieved within 2 hours. IR formulations provide a short duration of action and are therefore generally dosed three times per day. Sustained Release Formulation In humans, following oral administration of bupropion hydrochloride sustained-release tablets (SR), peak plasma concentration (Cmax) of bupropion is usually achieved within 3 hours. SR formulations provide a 12-hour extended release of medication and are therefore generally dosed twice per day. Extended Release Formulation Following single oral administration of bupropion hydrochloride extended-release tablets (XL) to healthy volunteers, the median time to peak plasma concentrations for bupropion was approximately 5 hours. The presence of food did not affect the peak concentration or area under the curve of bupropion. XL formulations provide a 24-hour extended release of medication and are therefore generally dosed once per day/ In a trial comparing chronic dosing with bupropion hydrochloride extended-release tablets (SR) 150 mg twice daily to bupropion immediate-release formulation 100 mg 3 times daily, the steady state Cmax for bupropion after bupropion hydrochloride sustained-release tablets (SR) administration was approximately 85% of those achieved after bupropion immediate-release formulation administration. Exposure (AUC) to bupropion was equivalent for both formulations. Bioequivalence was also demonstrated for all three major active metabolites (i.e., hydroxybupropion, threohydrobupropion and erythrohydrobupropion) for both Cmax and AUC. Thus, at steady state, bupropion hydrochloride sustained-release tablets (SR) given twice daily, and the immediate-release formulation of bupropion given 3 times daily, are essentially bioequivalent for both bupropion and the 3 quantitatively important metabolites. Furthermore, in a study comparing 14-day dosing with bupropion hydrochloride extended-release tablets (XL), 300 mg once-daily to the immediate-release formulation of bupropion at 100 mg 3 times daily, equivalence was demonstrated for peak plasma concentration and area under the curve for bupropion and the three metabolites (hydroxybupropion, threohydrobupropion, and erythrohydrobupropion). Additionally, in a study comparing 14-day dosing with bupropion hydrochloride extended-release tablets (XL) 300 mg once daily to the sustained-release formulation of bupropion at 150 mg 2 times daily, equivalence was demonstrated for peak plasma concentration and area under the curve for bupropion and the three metabolites. Bupropion hydrochloride extended-release tablets (SR) can be taken with or without food. Bupropion Cmax and AUC were increased by 11% to 35% and 16% to 19%, respectively, when bupropion hydrochloride extended-release tablets (SR) was administered with food to healthy volunteers in three trials. The food effect is not considered clinically significant. Following a single-dose administration of bupropion hydrochloride extended-release tablets (SR) in humans, Cmax of bupropion's metabolite hydroxybupropion occurs approximately 6 hours post-dose and is approximately 10 times the peak level of the parent drug at steady state. The elimination half-life of hydroxybupropion is approximately 20 (±5) hours and its AUC at steady state is about 17 times that of bupropion. The times to peak concentrations for the erythrohydrobupropion and threohydrobupropion metabolites are similar to that of the hydroxybupropion metabolite. However, their elimination half-lives are longer, 33(±10) and 37 (±13) hours, respectively, and steady-state AUCs are 1.5 and 7 times that of bupropion, respectively. •Absorption (Drug B): The absolute bioavailability of orally administered mirabegron ranges from 29% at a dose of 25 mg to 35% at a dose of 50 mg. The T max for the extended-release tablet and suspension formulations are approximately 3.5 hours, while the T max for the granule formulation is 4-5 hours. Both C max and AUC increase more than dose proportionally - an increase in dose from 50mg to 100mg results in a 2.9- and 2.6-fold increase in C max and AUC, respectively, whereas an increase from 50mg to 200mg results in a 8.4- and 6.5-fold increase in C max and AUC, respectively. Steady-state concentrations of mirabegron are achieved after approximately 7 days of once-daily administration. •Volume of distribution (Drug A): No volume of distribution available •Volume of distribution (Drug B): Following intravenous administration, mirabegron has an apparent steady-state volume of distribution (Vd) of 1670 L indicating extensive distribution. •Protein binding (Drug A): In vitro tests show that bupropion is 84% bound to human plasma proteins at concentrations up to 200 mcg per mL. The extent of protein binding of the hydroxybupropion metabolite is similar to that for bupropion, whereas the extent of protein binding of the threohydrobupropion metabolite is about half that seen with bupropion. •Protein binding (Drug B): Mirabegron is approximately 71% protein-bound in plasma, primarily to albumin and alpha-1-acid glycoprotein. •Metabolism (Drug A): Bupropion is extensively metabolized in humans. Three metabolites are active: hydroxybupropion, which is formed via hydroxylation of the tert-butyl group of bupropion, and the amino-alcohol isomers, threohydrobupropion and erythrohydrobupropion, which are formed via reduction of the carbonyl group. In vitro findings suggest that CYP2B6 is the principal isoenzyme involved in the formation of hydroxybupropion, while cytochrome P450 enzymes are not involved in the formation of threohydrobupropion. Hydroxybupropion has been shown to have the same affinity as bupropion for the norepinephrine transporter (NET) but approximately 50% of its antidepressant activity despite reaching concentrations of ~10-fold higher than that of the parent drug. Oxidation of the bupropion side chain results in the formation of a glycine conjugate of meta-chlorobenzoic acid, which is then excreted as the major urinary metabolite. The potency and toxicity of the metabolites relative to bupropion have not been fully characterized. However, it has been demonstrated in an antidepressant screening test in mice that hydroxybupropion is one-half as potent as bupropion, while threohydrobupropion and erythrohydrobupropion are 5-fold less potent than bupropion. This may be of clinical importance because the plasma concentrations of the metabolites are as high as or higher than those of bupropion. Bupropion and its metabolites exhibit linear kinetics following chronic administration of 300 to 450 mg per day. •Metabolism (Drug B): Mirabegron is extensively metabolized via a number of mechanisms, although unchanged parent drug is still the major circulating component following oral administration. Presumed metabolic pathways and their resultant metabolites include amide hydrolysis (M5, M16, M17), glucuronidation (mirabegron O-glucuronide, N-glucuronide, N-carbamoylglucuronide, M12), and secondary amine oxidation or dealkylation (M8, M9, M15), amongst others. The enzymes responsible for the oxidative metabolism of mirabegron are thought to be CYP3A4 and CYP2D6, while the UDP-glucuronosyltransferases responsible for conjugation reactions have been identified as UGT2B7, UGT1A3, and UGT1A8. Other enzymes that may be involved in the metabolism of mirabegron include butylcholinesterase and possibly alcohol dehydrogenase. •Route of elimination (Drug A): Bupropion is extensively metabolized in humans. Oxidation of the bupropion side chain results in the formation of a glycine conjugate of metachlorobenzoic acid, which is then excreted as the major urinary metabolite. Following oral administration of 200 mg of 14C-bupropion in humans, 87% and 10% of the radioactive dose were recovered in the urine and feces, respectively. However, the fraction of the oral dose of bupropion excreted unchanged was only 0.5%, a finding consistent with the extensive metabolism of bupropion. •Route of elimination (Drug B): Of a 160mg radiolabeled dose administered to healthy volunteers, approximately 55% of the radioactivity was recovered in the urine and 34% in the feces. Approximately 25% of unchanged mirabegron was recovered in the urine while 0% was recovered in the feces. Renal elimination is achieved primarily via active tubular secretion with some contribution by glomerular filtration. •Half-life (Drug A): 24 hours •Half-life (Drug B): The mean terminal elimination half-life of mirabegron in adults being treated for overactive bladder is approximately 50 hours. In pediatric patients receiving the granule formulation for the treatment of neurogenic detrusor overactivity, the mean terminal elimination half-life is approximately 26-31 hours. •Clearance (Drug A): No clearance available •Clearance (Drug B): Total plasma clearance following intravenous administration is approximately 57 L/h, with renal clearance accounting for roughly 25% at approximately 13 L/h. •Toxicity (Drug A): Symptoms of overdose include seizures, hallucinations, loss of consciousness, tachycardia, and cardiac arrest. •Toxicity (Drug B): At doses of up to 400mg in healthy volunteers (~8x the recommended maximum), reported symptoms of overdose included palpitations and increased heart rate. Symptoms of chronic overdosage are similar in presentation and may also include a rise in systolic blood pressure. In cases of overdosage, employ standard symptomatic and supportive measures in addition to ECG monitoring. •Brand Names (Drug A): Aplenzin, Auvelity, Budeprion, Contrave, Forfivo, Wellbutrin, Zyban •Brand Names (Drug B): Myrbetriq •Synonyms (Drug A): No synonyms listed •Synonyms (Drug B): No synonyms listed •Summary (Drug A): Bupropion is a norepinephrine and dopamine reuptake inhibitor used in the treatment of major depressive disorder (MDD), seasonal affective disorder (SAD), and as an aid to smoking cessation. •Summary (Drug B): Mirabegron is a beta-3 adrenergic agonist used to treat overactive bladder and neurogenic detrusor overactivity. Output: The subject drug is a strong CYP2D6 inhibitor and the affected drug is metabolized by CYP2D6. Concomitant administration may decrease the metabolism of the affected drug, which could increase serum concentrations as well as the risk and severity of adverse effects. The severity of the interaction is major.

Does Bupropion and Mirtazapine interact?

•Drug A: Bupropion •Drug B: Mirtazapine •Severity: MODERATE •Description: Bupropion may increase the central nervous system depressant (CNS depressant) activities of Mirtazapine. •Extended Description: The coadministration of central nervous system depressants and mirtazapine may potentiate the sedative effects of mirtazapine, due to synergistic pharmacological effects. •Indication (Drug A): Bupropion is indicated for the treatment of major depressive disorder (MDD), seasonal affective disorder (SAD), and as an aid to smoking cessation. When used in combination with naltrexone as the marketed product ContraveⓇ, bupropion is indicated as an adjunct to a reduced-calorie diet and increased physical activity for chronic weight management in adults with an initial body mass index (BMI) of: 30 kg/m^2 or greater (obese) or 27 kg/m^2 or greater (overweight) in the presence of at least one weight-related comorbid condition (e.g., hypertension, type 2 diabetes mellitus, or dyslipidemia). Bupropion is also used off-label as a first-line treatment in patients with ADHD and comorbid bipolar disorder when used as an adjunct to mood stabilizers. •Indication (Drug B): This drug is indicated for the treatment of major depressive disorder and its associated symptoms. Mirtazapine has been used off-label for a variety of conditions including panic disorder, generalized anxiety disorder, dysthymia, tension headaches, hot flushes, post-traumatic stress disorder (PTSD), sleep disorders, substance abuse disorders, and sexual disorders, among others. •Pharmacodynamics (Drug A): Bupropion is chemically unrelated to tricyclic, tetracyclic, selective serotonin re-uptake inhibitors, or other known antidepressant agents. Compared to classical tricyclic antidepressants, Bupropion is a relatively weak inhibitor of the neuronal uptake of norepinephrine and dopamine. In addition, Bupropion does not inhibit monoamine oxidase. Bupropion has been found to be essentially inactive at the serotonin transporter (SERT)(IC50 >10 000 nM), however both bupropion and its primary metabolite hydroxybupropion have been found to block the function of cation-selective serotonin type 3A receptors (5-HT3ARs). Bupropion produces dose-related central nervous system (CNS) stimulant effects in animals, as evidenced by increased locomotor activity, increased rates of responding in various schedule-controlled operant behaviour tasks, and, at high doses, induction of mild stereotyped behaviour. Due to these stimulant effects and selective activity at dopamine and norepinephrine receptors, bupropion has been identified as having an abuse potential. Bupropion has a similar structure to the controlled substance Cathinone, and has been identified as having mild amphetamine-like activity, particularly when inhaled or injected. Bupropion is also known to lower the seizure threshold, making any pre-existing seizure conditions a contraindication to its use. This risk is exacerbated when bupropion is combined with other drugs or substances that lower the seizure threshold, such as cocaine, or in clinical situations that would increase the risk of a seizure such as abrupt alcohol or benzodiazepine withdrawal. As norepinephrine has been shown to have anticonvulsant properties, bupropion's inhibitory effects on NET are thought to contribute to its pro-convulsant activity. Bupropion has been shown to increase blood pressure and pose a risk for exacerbation of unmanaged or pre-existing hypertension, however, clinical trials of bupropion in smokers with CVD have not identified an increased incidence of CV events including stroke or heart attack. In clinical trials, the mean increase in systolic blood pressure associated with the use of bupropion was found to be 1.3 mmHg. •Pharmacodynamics (Drug B): General effects and a note on suicidality Mirtazapine is effective in treating moderate to severe depression and treats many symptoms normally associated with this condition. These symptoms may include disturbed sleep, lack of appetite, and anhedonia, in addition to anxiety.. It is important to note that suicidal ideation and behavior may emerge or increase during treatment with mirtazapine, as with any other antidepressant. This risk is especially pronounced in younger individuals. Patients, medical professionals, and families should monitor for suicidal thoughts, worsening depression, anxiety, agitation, sleep changes, irritable behavior, aggression, impulsivity, restlessness, and other unusual behavior when this drug is taken or the dose is adjusted. Do not administer mirtazapine to children. When deciding to prescribe this drug, carefully consider the increased risk of suicidal thoughts and behavior, especially in young adults. Effects on appetite and weight gain In addition to the above effects, mirtazapine exerts stimulating effects on appetite, and has been used for increasing appetite and decreasing nausea in cancer patients. Some studies and case reports have shown that this drug improves eating habits and weight gain in patients suffering from anorexia nervosa when administered in conjunction with psychotherapy and/or other psychotropic drugs. In a clinical trial, women with depression experienced a clinically significant mean increase in body weight, fat mass, and concentrations of leptin when treated with mirtazapine for a 6-week period, with a lack of effect on glucose homeostasis. Effects on sleep The use of mirtazapine to treat disordered sleep has been leveraged from its tendency to cause somnolence, which is a frequently experienced adverse effect by patients taking this drug. Mirtazapine has been shown to exert beneficial effects on sleep latency, duration, and quality due to its sedating properties. Insomnia is a common occurrence in patients with depression, and mirtazapine has been found to be efficacious in treating this condition. •Mechanism of action (Drug A): Bupropion is a norepinephrine/dopamine-reuptake inhibitor (NDRI) that exerts its pharmacological effects by weakly inhibiting the enzymes involved in the uptake of the neurotransmitters norepinephrine and dopamine from the synaptic cleft, therefore prolonging their duration of action within the neuronal synapse and the downstream effects of these neurotransmitters. More specifically, bupropion binds to the norepinephrine transporter (NET) and the dopamine transporter (DAT). Bupropion was originally classified as an "atypical" antidepressant because it does not exert the same effects as the classical antidepressants such as Monoamine Oxidase Inhibitors (MAOIs), Tricyclic Antidepressants (TCAs), or Selective Serotonin Reuptake Inhibitors (SSRIs). While it has comparable effectiveness to typical first-line options for the treatment of depression such as SSRIs, bupropion is a unique option for the treatment of MDD as it lacks any clinically relevant serotonergic effects, typical of other mood medications, or any effects on histamine or adrenaline receptors. Lack of activity at these receptors results in a more tolerable side effect profile; bupropion is less likely to cause sexual side effects, sedation, or weight gain as compared to SSRIs or TCAs, for example. When used as an aid to smoking cessation, bupropion is thought to confer its anti-craving and anti-withdrawal effects by inhibiting dopamine reuptake, which is thought to be involved in the reward pathways associated with nicotine, and through the antagonism of the nicotinic acetylcholinergic receptor (AChR), thereby blunting the effects of nicotine. Furthermore, the stimulatory effects produced by bupropion in the central nervous system are similar to nicotine's effects, making low doses of bupropion a suitable option as a nicotine substitute. When used in combination with naltrexone in the marketed product ContraveⓇ for chronic weight management, the two components are thought to have effects on areas of the brain involved in the regulation of food intake. This includes the hypothalamus, which is involved in appetite regulation, and the mesolimbic dopamine circuit, which is involved in reward pathways. Studies have shown that the combined activity of bupropion and naltrexone increase the firing rate of hypothalamic pro-opiomelanocortin (POMC) neurons and blockade of opioid receptor-mediated POMC auto-inhibition, which are associated with a reduction in food intake and increased energy expenditure. This combination was also found to reduce food intake when injected directly into the ventral tegmental area of the mesolimbic circuit in mice, which is an area associated with the regulation of reward pathways. •Mechanism of action (Drug B): Summary The mechanism of action of mirtazapine is not fully understood but may be explained by its effects on central adrenergic and serotonergic activity. This drug exhibits a fast onset of action, a high level of response, a manageable side-effect profile, and dual noradrenergic and serotonergic effects that are unique from the effects of other antidepressants. Effects on various receptors It has been shown that both noradrenergic and serotonergic activity increase following mirtazapine administration. The results of these studies demonstrate mirtazapine exerts antagonist activity at presynaptic α2-adrenergic inhibitory autoreceptors and heteroreceptors in the central nervous system. This is thought to lead to enhanced noradrenergic and serotonergic activity, which are known to improve the symptoms of depression and form the basis of antidepressant therapy. Mirtazapine is a strong antagonist of serotonin 5-HT2 and 5-HT3 receptors. It has not been found to bind significantly to the serotonin 5-HT1A and 5-HT1B receptors but indirectly increases 5-HT1A transmission. In addition to the above effects, mirtazapine is a peripheral α1-adrenergic antagonist. This action may explain episodes of orthostatic hypotension that have been reported after mirtazapine use. Mirtazapine is a potent histamine (H1) receptor antagonist, which may contribute to its powerful sedating effects. The pain-relieving effects of mirtazapine may be explained by its effects on opioid receptors. •Absorption (Drug A): Bupropion is currently available in 3 distinct, but bioequivalent formulations: immediate release (IR), sustained-release (SR), and extended-release (XL). Immediate Release Formulation In humans, following oral administration of bupropion hydrochloride tablets, peak plasma bupropion concentrations are usually achieved within 2 hours. IR formulations provide a short duration of action and are therefore generally dosed three times per day. Sustained Release Formulation In humans, following oral administration of bupropion hydrochloride sustained-release tablets (SR), peak plasma concentration (Cmax) of bupropion is usually achieved within 3 hours. SR formulations provide a 12-hour extended release of medication and are therefore generally dosed twice per day. Extended Release Formulation Following single oral administration of bupropion hydrochloride extended-release tablets (XL) to healthy volunteers, the median time to peak plasma concentrations for bupropion was approximately 5 hours. The presence of food did not affect the peak concentration or area under the curve of bupropion. XL formulations provide a 24-hour extended release of medication and are therefore generally dosed once per day/ In a trial comparing chronic dosing with bupropion hydrochloride extended-release tablets (SR) 150 mg twice daily to bupropion immediate-release formulation 100 mg 3 times daily, the steady state Cmax for bupropion after bupropion hydrochloride sustained-release tablets (SR) administration was approximately 85% of those achieved after bupropion immediate-release formulation administration. Exposure (AUC) to bupropion was equivalent for both formulations. Bioequivalence was also demonstrated for all three major active metabolites (i.e., hydroxybupropion, threohydrobupropion and erythrohydrobupropion) for both Cmax and AUC. Thus, at steady state, bupropion hydrochloride sustained-release tablets (SR) given twice daily, and the immediate-release formulation of bupropion given 3 times daily, are essentially bioequivalent for both bupropion and the 3 quantitatively important metabolites. Furthermore, in a study comparing 14-day dosing with bupropion hydrochloride extended-release tablets (XL), 300 mg once-daily to the immediate-release formulation of bupropion at 100 mg 3 times daily, equivalence was demonstrated for peak plasma concentration and area under the curve for bupropion and the three metabolites (hydroxybupropion, threohydrobupropion, and erythrohydrobupropion). Additionally, in a study comparing 14-day dosing with bupropion hydrochloride extended-release tablets (XL) 300 mg once daily to the sustained-release formulation of bupropion at 150 mg 2 times daily, equivalence was demonstrated for peak plasma concentration and area under the curve for bupropion and the three metabolites. Bupropion hydrochloride extended-release tablets (SR) can be taken with or without food. Bupropion Cmax and AUC were increased by 11% to 35% and 16% to 19%, respectively, when bupropion hydrochloride extended-release tablets (SR) was administered with food to healthy volunteers in three trials. The food effect is not considered clinically significant. Following a single-dose administration of bupropion hydrochloride extended-release tablets (SR) in humans, Cmax of bupropion's metabolite hydroxybupropion occurs approximately 6 hours post-dose and is approximately 10 times the peak level of the parent drug at steady state. The elimination half-life of hydroxybupropion is approximately 20 (±5) hours and its AUC at steady state is about 17 times that of bupropion. The times to peak concentrations for the erythrohydrobupropion and threohydrobupropion metabolites are similar to that of the hydroxybupropion metabolite. However, their elimination half-lives are longer, 33(±10) and 37 (±13) hours, respectively, and steady-state AUCs are 1.5 and 7 times that of bupropion, respectively. •Absorption (Drug B): The absorption of this drug is rapid and complete. Due to first pass metabolism in the liver and metabolism in the gut wall, absolute bioavailability is about 50%. Peak blood concentrations are attained within about 2 hours after an oral dose. Food has little effect on the absorption of mirtazapine, and no dose adjustment is required if it is taken with food. Steady-state levels are achieved by about 5 days after the initial dose. Mirtazapine pharmacokinetics vary across gender and age range. Females and the elderly population have been shown to have higher blood concentrations in comparison to males and younger adults. •Volume of distribution (Drug A): No volume of distribution available •Volume of distribution (Drug B): The volume of distribution after an oral steady-state dose was measured to be 107 ± 42L in a pharmacokinetic study. •Protein binding (Drug A): In vitro tests show that bupropion is 84% bound to human plasma proteins at concentrations up to 200 mcg per mL. The extent of protein binding of the hydroxybupropion metabolite is similar to that for bupropion, whereas the extent of protein binding of the threohydrobupropion metabolite is about half that seen with bupropion. •Protein binding (Drug B): Mirtazapine is about 85% bound to plasma proteins. •Metabolism (Drug A): Bupropion is extensively metabolized in humans. Three metabolites are active: hydroxybupropion, which is formed via hydroxylation of the tert-butyl group of bupropion, and the amino-alcohol isomers, threohydrobupropion and erythrohydrobupropion, which are formed via reduction of the carbonyl group. In vitro findings suggest that CYP2B6 is the principal isoenzyme involved in the formation of hydroxybupropion, while cytochrome P450 enzymes are not involved in the formation of threohydrobupropion. Hydroxybupropion has been shown to have the same affinity as bupropion for the norepinephrine transporter (NET) but approximately 50% of its antidepressant activity despite reaching concentrations of ~10-fold higher than that of the parent drug. Oxidation of the bupropion side chain results in the formation of a glycine conjugate of meta-chlorobenzoic acid, which is then excreted as the major urinary metabolite. The potency and toxicity of the metabolites relative to bupropion have not been fully characterized. However, it has been demonstrated in an antidepressant screening test in mice that hydroxybupropion is one-half as potent as bupropion, while threohydrobupropion and erythrohydrobupropion are 5-fold less potent than bupropion. This may be of clinical importance because the plasma concentrations of the metabolites are as high as or higher than those of bupropion. Bupropion and its metabolites exhibit linear kinetics following chronic administration of 300 to 450 mg per day. •Metabolism (Drug B): Mirtazapine is heavily metabolized in humans. Demethylation and hydroxylation and subsequent glucuronide conjugation are the major pathways by which mirtazapine is metabolized. Data from in vitro studies on human liver microsomes show that cytochrome 2D6 and 1A2 lead to the formation of the 8-hydroxy metabolite of mirtazapine. The CYP3A enzyme metabolizes this drug into its N-desmethyl and N-oxide metabolites. There are various other unconjugated metabolites of this drug that are pharmacologically active, but are measured in the blood at limited concentrations. •Route of elimination (Drug A): Bupropion is extensively metabolized in humans. Oxidation of the bupropion side chain results in the formation of a glycine conjugate of metachlorobenzoic acid, which is then excreted as the major urinary metabolite. Following oral administration of 200 mg of 14C-bupropion in humans, 87% and 10% of the radioactive dose were recovered in the urine and feces, respectively. However, the fraction of the oral dose of bupropion excreted unchanged was only 0.5%, a finding consistent with the extensive metabolism of bupropion. •Route of elimination (Drug B): This drug is mainly excreted by the kidney. It is 75% eliminated in the urine and 15% eliminated in the feces. •Half-life (Drug A): 24 hours •Half-life (Drug B): 20-40 hours •Clearance (Drug A): No clearance available •Clearance (Drug B): Total body clearance in males was found to be 31 L/h in a clinical pharmacokinetics study after intravenous administration. Clearance in elderly patients Mirtazapine clearance is slower in the elderly than in younger subjects. Exercise caution when this drug is given to elderly patients. In a clinical trial, elderly males showed a marked decrease in mirtazapine clearance when compared to young males taking the same dose. This difference was less significant when clearance was compared between elderly females and younger females taking mirtazapine. Clearance in hepatic and renal impairment Patients with hepatic and renal impairment have decreased rates of clearance and dosage adjustments may be necessary for these patients. Moderate renal impairment and hepatic impairment cause about a 30% decrease in mirtazapine clearance. Severe renal impairment leads to a 50% decrease in mirtazapine clearance. •Toxicity (Drug A): Symptoms of overdose include seizures, hallucinations, loss of consciousness, tachycardia, and cardiac arrest. •Toxicity (Drug B): LD50 Oral LD50 was 830 mg/kg in male Swiss mice 24 hours after being administered mirtazapine. Overdose information Activated charcoal should be administered during an overdose to absorb excess mirtazapine. General supportive therapy should be employed, including maintenance of an adequate airway, oxygen therapy, and ventilation therapy. Vital signs and cardiac rhythm must be monitored. It is not advisable to induce vomiting. Gastric lavage with a large-bore orogastric tube with proper protection of the airway is recommended. There is no antidote for mirtazapine available currently. Consider the possibility of mirtazapine combined with other drugs in an overdose and ensure to contact the local poison control center for guidance on management. Carcinogenesis At higher than normal doses, mirtazapine increased the incidence of hepatocellular adenomas and carcinomas in male mice. The highest doses administered to the mice were about 20 and 12 times the maximum recommended human dose (MRHD). Hepatocellular tumors and thyroid follicular adenoma/cystadenomas in male rats occurred at an increased rate at a higher mirtazapine dose (60 mg/kg/day). In female rats, both the medium (20 mg/kg/day) and higher (60 mg/kg/day) doses of mirtazapine increased the rate of hepatocellular adenomas. The relevance of these findings in humans is not known at this time. Impairment of Fertility Mirtazapine was administered to rats at doses reaching 100 mg/kg (equivalent to 20 times the maximum recommended human dose) in a fertility study. There was no impact on mating and conception, however, there was a disturbance of reproductive (estrous) cycling at higher doses. These doses were measured to be at least 3 times the maximum recommended human dose. Loss of fetus before implantation in the uterus occurred when doses equivalent to 20 times the maximum recommended dose were administered. Use in pregnancy This drug is categorized as a pregnancy category C drug. No adequate studies in pregnant women have been conducted. In rats, an increased rate of post-implantation demise occurred with mirtazapine administration. Additionally, an increase in deaths of rat pups during the first 3 days of lactation with a decrease in pup birth weight was noted. Studies on animals are not always relevant to human response. Mirtazapine should be used during pregnancy only if the clinical need outweighs the possible risks to the fetus. Use in nursing Whether this drug is excreted in human milk is unknown. Many drugs are found excreted in human breast milk, therefore caution is advised if this drug is used during nursing. •Brand Names (Drug A): Aplenzin, Auvelity, Budeprion, Contrave, Forfivo, Wellbutrin, Zyban •Brand Names (Drug B): Remeron •Synonyms (Drug A): No synonyms listed •Synonyms (Drug B): 6-Azamianserin Mepirzapine Mirtazapin Mirtazapina Mirtazapine Mirtazapinum •Summary (Drug A): Bupropion is a norepinephrine and dopamine reuptake inhibitor used in the treatment of major depressive disorder (MDD), seasonal affective disorder (SAD), and as an aid to smoking cessation. •Summary (Drug B): Mirtazapine is a tetracyclic antidepressant used in the treatment of major depression and is used off-label as a drug for insomnia and to increase appetite.

The coadministration of central nervous system depressants and mirtazapine may potentiate the sedative effects of mirtazapine, due to synergistic pharmacological effects. The severity of the interaction is moderate.

Question: Does Bupropion and Mirtazapine interact? Information: •Drug A: Bupropion •Drug B: Mirtazapine •Severity: MODERATE •Description: Bupropion may increase the central nervous system depressant (CNS depressant) activities of Mirtazapine. •Extended Description: The coadministration of central nervous system depressants and mirtazapine may potentiate the sedative effects of mirtazapine, due to synergistic pharmacological effects. •Indication (Drug A): Bupropion is indicated for the treatment of major depressive disorder (MDD), seasonal affective disorder (SAD), and as an aid to smoking cessation. When used in combination with naltrexone as the marketed product ContraveⓇ, bupropion is indicated as an adjunct to a reduced-calorie diet and increased physical activity for chronic weight management in adults with an initial body mass index (BMI) of: 30 kg/m^2 or greater (obese) or 27 kg/m^2 or greater (overweight) in the presence of at least one weight-related comorbid condition (e.g., hypertension, type 2 diabetes mellitus, or dyslipidemia). Bupropion is also used off-label as a first-line treatment in patients with ADHD and comorbid bipolar disorder when used as an adjunct to mood stabilizers. •Indication (Drug B): This drug is indicated for the treatment of major depressive disorder and its associated symptoms. Mirtazapine has been used off-label for a variety of conditions including panic disorder, generalized anxiety disorder, dysthymia, tension headaches, hot flushes, post-traumatic stress disorder (PTSD), sleep disorders, substance abuse disorders, and sexual disorders, among others. •Pharmacodynamics (Drug A): Bupropion is chemically unrelated to tricyclic, tetracyclic, selective serotonin re-uptake inhibitors, or other known antidepressant agents. Compared to classical tricyclic antidepressants, Bupropion is a relatively weak inhibitor of the neuronal uptake of norepinephrine and dopamine. In addition, Bupropion does not inhibit monoamine oxidase. Bupropion has been found to be essentially inactive at the serotonin transporter (SERT)(IC50 >10 000 nM), however both bupropion and its primary metabolite hydroxybupropion have been found to block the function of cation-selective serotonin type 3A receptors (5-HT3ARs). Bupropion produces dose-related central nervous system (CNS) stimulant effects in animals, as evidenced by increased locomotor activity, increased rates of responding in various schedule-controlled operant behaviour tasks, and, at high doses, induction of mild stereotyped behaviour. Due to these stimulant effects and selective activity at dopamine and norepinephrine receptors, bupropion has been identified as having an abuse potential. Bupropion has a similar structure to the controlled substance Cathinone, and has been identified as having mild amphetamine-like activity, particularly when inhaled or injected. Bupropion is also known to lower the seizure threshold, making any pre-existing seizure conditions a contraindication to its use. This risk is exacerbated when bupropion is combined with other drugs or substances that lower the seizure threshold, such as cocaine, or in clinical situations that would increase the risk of a seizure such as abrupt alcohol or benzodiazepine withdrawal. As norepinephrine has been shown to have anticonvulsant properties, bupropion's inhibitory effects on NET are thought to contribute to its pro-convulsant activity. Bupropion has been shown to increase blood pressure and pose a risk for exacerbation of unmanaged or pre-existing hypertension, however, clinical trials of bupropion in smokers with CVD have not identified an increased incidence of CV events including stroke or heart attack. In clinical trials, the mean increase in systolic blood pressure associated with the use of bupropion was found to be 1.3 mmHg. •Pharmacodynamics (Drug B): General effects and a note on suicidality Mirtazapine is effective in treating moderate to severe depression and treats many symptoms normally associated with this condition. These symptoms may include disturbed sleep, lack of appetite, and anhedonia, in addition to anxiety.. It is important to note that suicidal ideation and behavior may emerge or increase during treatment with mirtazapine, as with any other antidepressant. This risk is especially pronounced in younger individuals. Patients, medical professionals, and families should monitor for suicidal thoughts, worsening depression, anxiety, agitation, sleep changes, irritable behavior, aggression, impulsivity, restlessness, and other unusual behavior when this drug is taken or the dose is adjusted. Do not administer mirtazapine to children. When deciding to prescribe this drug, carefully consider the increased risk of suicidal thoughts and behavior, especially in young adults. Effects on appetite and weight gain In addition to the above effects, mirtazapine exerts stimulating effects on appetite, and has been used for increasing appetite and decreasing nausea in cancer patients. Some studies and case reports have shown that this drug improves eating habits and weight gain in patients suffering from anorexia nervosa when administered in conjunction with psychotherapy and/or other psychotropic drugs. In a clinical trial, women with depression experienced a clinically significant mean increase in body weight, fat mass, and concentrations of leptin when treated with mirtazapine for a 6-week period, with a lack of effect on glucose homeostasis. Effects on sleep The use of mirtazapine to treat disordered sleep has been leveraged from its tendency to cause somnolence, which is a frequently experienced adverse effect by patients taking this drug. Mirtazapine has been shown to exert beneficial effects on sleep latency, duration, and quality due to its sedating properties. Insomnia is a common occurrence in patients with depression, and mirtazapine has been found to be efficacious in treating this condition. •Mechanism of action (Drug A): Bupropion is a norepinephrine/dopamine-reuptake inhibitor (NDRI) that exerts its pharmacological effects by weakly inhibiting the enzymes involved in the uptake of the neurotransmitters norepinephrine and dopamine from the synaptic cleft, therefore prolonging their duration of action within the neuronal synapse and the downstream effects of these neurotransmitters. More specifically, bupropion binds to the norepinephrine transporter (NET) and the dopamine transporter (DAT). Bupropion was originally classified as an "atypical" antidepressant because it does not exert the same effects as the classical antidepressants such as Monoamine Oxidase Inhibitors (MAOIs), Tricyclic Antidepressants (TCAs), or Selective Serotonin Reuptake Inhibitors (SSRIs). While it has comparable effectiveness to typical first-line options for the treatment of depression such as SSRIs, bupropion is a unique option for the treatment of MDD as it lacks any clinically relevant serotonergic effects, typical of other mood medications, or any effects on histamine or adrenaline receptors. Lack of activity at these receptors results in a more tolerable side effect profile; bupropion is less likely to cause sexual side effects, sedation, or weight gain as compared to SSRIs or TCAs, for example. When used as an aid to smoking cessation, bupropion is thought to confer its anti-craving and anti-withdrawal effects by inhibiting dopamine reuptake, which is thought to be involved in the reward pathways associated with nicotine, and through the antagonism of the nicotinic acetylcholinergic receptor (AChR), thereby blunting the effects of nicotine. Furthermore, the stimulatory effects produced by bupropion in the central nervous system are similar to nicotine's effects, making low doses of bupropion a suitable option as a nicotine substitute. When used in combination with naltrexone in the marketed product ContraveⓇ for chronic weight management, the two components are thought to have effects on areas of the brain involved in the regulation of food intake. This includes the hypothalamus, which is involved in appetite regulation, and the mesolimbic dopamine circuit, which is involved in reward pathways. Studies have shown that the combined activity of bupropion and naltrexone increase the firing rate of hypothalamic pro-opiomelanocortin (POMC) neurons and blockade of opioid receptor-mediated POMC auto-inhibition, which are associated with a reduction in food intake and increased energy expenditure. This combination was also found to reduce food intake when injected directly into the ventral tegmental area of the mesolimbic circuit in mice, which is an area associated with the regulation of reward pathways. •Mechanism of action (Drug B): Summary The mechanism of action of mirtazapine is not fully understood but may be explained by its effects on central adrenergic and serotonergic activity. This drug exhibits a fast onset of action, a high level of response, a manageable side-effect profile, and dual noradrenergic and serotonergic effects that are unique from the effects of other antidepressants. Effects on various receptors It has been shown that both noradrenergic and serotonergic activity increase following mirtazapine administration. The results of these studies demonstrate mirtazapine exerts antagonist activity at presynaptic α2-adrenergic inhibitory autoreceptors and heteroreceptors in the central nervous system. This is thought to lead to enhanced noradrenergic and serotonergic activity, which are known to improve the symptoms of depression and form the basis of antidepressant therapy. Mirtazapine is a strong antagonist of serotonin 5-HT2 and 5-HT3 receptors. It has not been found to bind significantly to the serotonin 5-HT1A and 5-HT1B receptors but indirectly increases 5-HT1A transmission. In addition to the above effects, mirtazapine is a peripheral α1-adrenergic antagonist. This action may explain episodes of orthostatic hypotension that have been reported after mirtazapine use. Mirtazapine is a potent histamine (H1) receptor antagonist, which may contribute to its powerful sedating effects. The pain-relieving effects of mirtazapine may be explained by its effects on opioid receptors. •Absorption (Drug A): Bupropion is currently available in 3 distinct, but bioequivalent formulations: immediate release (IR), sustained-release (SR), and extended-release (XL). Immediate Release Formulation In humans, following oral administration of bupropion hydrochloride tablets, peak plasma bupropion concentrations are usually achieved within 2 hours. IR formulations provide a short duration of action and are therefore generally dosed three times per day. Sustained Release Formulation In humans, following oral administration of bupropion hydrochloride sustained-release tablets (SR), peak plasma concentration (Cmax) of bupropion is usually achieved within 3 hours. SR formulations provide a 12-hour extended release of medication and are therefore generally dosed twice per day. Extended Release Formulation Following single oral administration of bupropion hydrochloride extended-release tablets (XL) to healthy volunteers, the median time to peak plasma concentrations for bupropion was approximately 5 hours. The presence of food did not affect the peak concentration or area under the curve of bupropion. XL formulations provide a 24-hour extended release of medication and are therefore generally dosed once per day/ In a trial comparing chronic dosing with bupropion hydrochloride extended-release tablets (SR) 150 mg twice daily to bupropion immediate-release formulation 100 mg 3 times daily, the steady state Cmax for bupropion after bupropion hydrochloride sustained-release tablets (SR) administration was approximately 85% of those achieved after bupropion immediate-release formulation administration. Exposure (AUC) to bupropion was equivalent for both formulations. Bioequivalence was also demonstrated for all three major active metabolites (i.e., hydroxybupropion, threohydrobupropion and erythrohydrobupropion) for both Cmax and AUC. Thus, at steady state, bupropion hydrochloride sustained-release tablets (SR) given twice daily, and the immediate-release formulation of bupropion given 3 times daily, are essentially bioequivalent for both bupropion and the 3 quantitatively important metabolites. Furthermore, in a study comparing 14-day dosing with bupropion hydrochloride extended-release tablets (XL), 300 mg once-daily to the immediate-release formulation of bupropion at 100 mg 3 times daily, equivalence was demonstrated for peak plasma concentration and area under the curve for bupropion and the three metabolites (hydroxybupropion, threohydrobupropion, and erythrohydrobupropion). Additionally, in a study comparing 14-day dosing with bupropion hydrochloride extended-release tablets (XL) 300 mg once daily to the sustained-release formulation of bupropion at 150 mg 2 times daily, equivalence was demonstrated for peak plasma concentration and area under the curve for bupropion and the three metabolites. Bupropion hydrochloride extended-release tablets (SR) can be taken with or without food. Bupropion Cmax and AUC were increased by 11% to 35% and 16% to 19%, respectively, when bupropion hydrochloride extended-release tablets (SR) was administered with food to healthy volunteers in three trials. The food effect is not considered clinically significant. Following a single-dose administration of bupropion hydrochloride extended-release tablets (SR) in humans, Cmax of bupropion's metabolite hydroxybupropion occurs approximately 6 hours post-dose and is approximately 10 times the peak level of the parent drug at steady state. The elimination half-life of hydroxybupropion is approximately 20 (±5) hours and its AUC at steady state is about 17 times that of bupropion. The times to peak concentrations for the erythrohydrobupropion and threohydrobupropion metabolites are similar to that of the hydroxybupropion metabolite. However, their elimination half-lives are longer, 33(±10) and 37 (±13) hours, respectively, and steady-state AUCs are 1.5 and 7 times that of bupropion, respectively. •Absorption (Drug B): The absorption of this drug is rapid and complete. Due to first pass metabolism in the liver and metabolism in the gut wall, absolute bioavailability is about 50%. Peak blood concentrations are attained within about 2 hours after an oral dose. Food has little effect on the absorption of mirtazapine, and no dose adjustment is required if it is taken with food. Steady-state levels are achieved by about 5 days after the initial dose. Mirtazapine pharmacokinetics vary across gender and age range. Females and the elderly population have been shown to have higher blood concentrations in comparison to males and younger adults. •Volume of distribution (Drug A): No volume of distribution available •Volume of distribution (Drug B): The volume of distribution after an oral steady-state dose was measured to be 107 ± 42L in a pharmacokinetic study. •Protein binding (Drug A): In vitro tests show that bupropion is 84% bound to human plasma proteins at concentrations up to 200 mcg per mL. The extent of protein binding of the hydroxybupropion metabolite is similar to that for bupropion, whereas the extent of protein binding of the threohydrobupropion metabolite is about half that seen with bupropion. •Protein binding (Drug B): Mirtazapine is about 85% bound to plasma proteins. •Metabolism (Drug A): Bupropion is extensively metabolized in humans. Three metabolites are active: hydroxybupropion, which is formed via hydroxylation of the tert-butyl group of bupropion, and the amino-alcohol isomers, threohydrobupropion and erythrohydrobupropion, which are formed via reduction of the carbonyl group. In vitro findings suggest that CYP2B6 is the principal isoenzyme involved in the formation of hydroxybupropion, while cytochrome P450 enzymes are not involved in the formation of threohydrobupropion. Hydroxybupropion has been shown to have the same affinity as bupropion for the norepinephrine transporter (NET) but approximately 50% of its antidepressant activity despite reaching concentrations of ~10-fold higher than that of the parent drug. Oxidation of the bupropion side chain results in the formation of a glycine conjugate of meta-chlorobenzoic acid, which is then excreted as the major urinary metabolite. The potency and toxicity of the metabolites relative to bupropion have not been fully characterized. However, it has been demonstrated in an antidepressant screening test in mice that hydroxybupropion is one-half as potent as bupropion, while threohydrobupropion and erythrohydrobupropion are 5-fold less potent than bupropion. This may be of clinical importance because the plasma concentrations of the metabolites are as high as or higher than those of bupropion. Bupropion and its metabolites exhibit linear kinetics following chronic administration of 300 to 450 mg per day. •Metabolism (Drug B): Mirtazapine is heavily metabolized in humans. Demethylation and hydroxylation and subsequent glucuronide conjugation are the major pathways by which mirtazapine is metabolized. Data from in vitro studies on human liver microsomes show that cytochrome 2D6 and 1A2 lead to the formation of the 8-hydroxy metabolite of mirtazapine. The CYP3A enzyme metabolizes this drug into its N-desmethyl and N-oxide metabolites. There are various other unconjugated metabolites of this drug that are pharmacologically active, but are measured in the blood at limited concentrations. •Route of elimination (Drug A): Bupropion is extensively metabolized in humans. Oxidation of the bupropion side chain results in the formation of a glycine conjugate of metachlorobenzoic acid, which is then excreted as the major urinary metabolite. Following oral administration of 200 mg of 14C-bupropion in humans, 87% and 10% of the radioactive dose were recovered in the urine and feces, respectively. However, the fraction of the oral dose of bupropion excreted unchanged was only 0.5%, a finding consistent with the extensive metabolism of bupropion. •Route of elimination (Drug B): This drug is mainly excreted by the kidney. It is 75% eliminated in the urine and 15% eliminated in the feces. •Half-life (Drug A): 24 hours •Half-life (Drug B): 20-40 hours •Clearance (Drug A): No clearance available •Clearance (Drug B): Total body clearance in males was found to be 31 L/h in a clinical pharmacokinetics study after intravenous administration. Clearance in elderly patients Mirtazapine clearance is slower in the elderly than in younger subjects. Exercise caution when this drug is given to elderly patients. In a clinical trial, elderly males showed a marked decrease in mirtazapine clearance when compared to young males taking the same dose. This difference was less significant when clearance was compared between elderly females and younger females taking mirtazapine. Clearance in hepatic and renal impairment Patients with hepatic and renal impairment have decreased rates of clearance and dosage adjustments may be necessary for these patients. Moderate renal impairment and hepatic impairment cause about a 30% decrease in mirtazapine clearance. Severe renal impairment leads to a 50% decrease in mirtazapine clearance. •Toxicity (Drug A): Symptoms of overdose include seizures, hallucinations, loss of consciousness, tachycardia, and cardiac arrest. •Toxicity (Drug B): LD50 Oral LD50 was 830 mg/kg in male Swiss mice 24 hours after being administered mirtazapine. Overdose information Activated charcoal should be administered during an overdose to absorb excess mirtazapine. General supportive therapy should be employed, including maintenance of an adequate airway, oxygen therapy, and ventilation therapy. Vital signs and cardiac rhythm must be monitored. It is not advisable to induce vomiting. Gastric lavage with a large-bore orogastric tube with proper protection of the airway is recommended. There is no antidote for mirtazapine available currently. Consider the possibility of mirtazapine combined with other drugs in an overdose and ensure to contact the local poison control center for guidance on management. Carcinogenesis At higher than normal doses, mirtazapine increased the incidence of hepatocellular adenomas and carcinomas in male mice. The highest doses administered to the mice were about 20 and 12 times the maximum recommended human dose (MRHD). Hepatocellular tumors and thyroid follicular adenoma/cystadenomas in male rats occurred at an increased rate at a higher mirtazapine dose (60 mg/kg/day). In female rats, both the medium (20 mg/kg/day) and higher (60 mg/kg/day) doses of mirtazapine increased the rate of hepatocellular adenomas. The relevance of these findings in humans is not known at this time. Impairment of Fertility Mirtazapine was administered to rats at doses reaching 100 mg/kg (equivalent to 20 times the maximum recommended human dose) in a fertility study. There was no impact on mating and conception, however, there was a disturbance of reproductive (estrous) cycling at higher doses. These doses were measured to be at least 3 times the maximum recommended human dose. Loss of fetus before implantation in the uterus occurred when doses equivalent to 20 times the maximum recommended dose were administered. Use in pregnancy This drug is categorized as a pregnancy category C drug. No adequate studies in pregnant women have been conducted. In rats, an increased rate of post-implantation demise occurred with mirtazapine administration. Additionally, an increase in deaths of rat pups during the first 3 days of lactation with a decrease in pup birth weight was noted. Studies on animals are not always relevant to human response. Mirtazapine should be used during pregnancy only if the clinical need outweighs the possible risks to the fetus. Use in nursing Whether this drug is excreted in human milk is unknown. Many drugs are found excreted in human breast milk, therefore caution is advised if this drug is used during nursing. •Brand Names (Drug A): Aplenzin, Auvelity, Budeprion, Contrave, Forfivo, Wellbutrin, Zyban •Brand Names (Drug B): Remeron •Synonyms (Drug A): No synonyms listed •Synonyms (Drug B): 6-Azamianserin Mepirzapine Mirtazapin Mirtazapina Mirtazapine Mirtazapinum •Summary (Drug A): Bupropion is a norepinephrine and dopamine reuptake inhibitor used in the treatment of major depressive disorder (MDD), seasonal affective disorder (SAD), and as an aid to smoking cessation. •Summary (Drug B): Mirtazapine is a tetracyclic antidepressant used in the treatment of major depression and is used off-label as a drug for insomnia and to increase appetite. Output: The coadministration of central nervous system depressants and mirtazapine may potentiate the sedative effects of mirtazapine, due to synergistic pharmacological effects. The severity of the interaction is moderate.

Does Bupropion and Mitapivat interact?

•Drug A: Bupropion •Drug B: Mitapivat •Severity: MODERATE •Description: The metabolism of Bupropion can be increased when combined with Mitapivat. •Extended Description: When a CYP2B6 substrate is administered concurrently with a CYP2B6 inducer of unknown strength, the CYP2B6 mediated metabolism of the substrate will subsequently be enhanced - either slightly, moderately, or greatly. Such increases in metabolism consequently result in decreases in the substrate's serum concentration and/or therapeutic effect. •Indication (Drug A): Bupropion is indicated for the treatment of major depressive disorder (MDD), seasonal affective disorder (SAD), and as an aid to smoking cessation. When used in combination with naltrexone as the marketed product ContraveⓇ, bupropion is indicated as an adjunct to a reduced-calorie diet and increased physical activity for chronic weight management in adults with an initial body mass index (BMI) of: 30 kg/m^2 or greater (obese) or 27 kg/m^2 or greater (overweight) in the presence of at least one weight-related comorbid condition (e.g., hypertension, type 2 diabetes mellitus, or dyslipidemia). Bupropion is also used off-label as a first-line treatment in patients with ADHD and comorbid bipolar disorder when used as an adjunct to mood stabilizers. •Indication (Drug B): Mitapivat is indicated for the treatment of hemolytic anemia in adults with pyruvate kinase (PK) deficiency. •Pharmacodynamics (Drug A): Bupropion is chemically unrelated to tricyclic, tetracyclic, selective serotonin re-uptake inhibitors, or other known antidepressant agents. Compared to classical tricyclic antidepressants, Bupropion is a relatively weak inhibitor of the neuronal uptake of norepinephrine and dopamine. In addition, Bupropion does not inhibit monoamine oxidase. Bupropion has been found to be essentially inactive at the serotonin transporter (SERT)(IC50 >10 000 nM), however both bupropion and its primary metabolite hydroxybupropion have been found to block the function of cation-selective serotonin type 3A receptors (5-HT3ARs). Bupropion produces dose-related central nervous system (CNS) stimulant effects in animals, as evidenced by increased locomotor activity, increased rates of responding in various schedule-controlled operant behaviour tasks, and, at high doses, induction of mild stereotyped behaviour. Due to these stimulant effects and selective activity at dopamine and norepinephrine receptors, bupropion has been identified as having an abuse potential. Bupropion has a similar structure to the controlled substance Cathinone, and has been identified as having mild amphetamine-like activity, particularly when inhaled or injected. Bupropion is also known to lower the seizure threshold, making any pre-existing seizure conditions a contraindication to its use. This risk is exacerbated when bupropion is combined with other drugs or substances that lower the seizure threshold, such as cocaine, or in clinical situations that would increase the risk of a seizure such as abrupt alcohol or benzodiazepine withdrawal. As norepinephrine has been shown to have anticonvulsant properties, bupropion's inhibitory effects on NET are thought to contribute to its pro-convulsant activity. Bupropion has been shown to increase blood pressure and pose a risk for exacerbation of unmanaged or pre-existing hypertension, however, clinical trials of bupropion in smokers with CVD have not identified an increased incidence of CV events including stroke or heart attack. In clinical trials, the mean increase in systolic blood pressure associated with the use of bupropion was found to be 1.3 mmHg. •Pharmacodynamics (Drug B): Mitapivat is a pyruvate kinase activator that works to increase the activity of erythrocyte pyruvate kinase, an enzyme responsible for energy production for and survival of red blood cells. It is effective in upregulating the activity of both wild-type and mutant forms of erythrocyte pyruvate kinase. Interestingly, mitapivat is a mild-to-moderate inhibitor of the aromatase enzyme (CYP19A1), which is an enzyme involved in biosynthesis of estrogens from androgen precursors. Inhibition of aromatase is associated with bone density loss, as estrogen mediates suppressive, antiresorptive effects on osteoclasts and generally favours bone formation over resorption. Thus, low estrogen levels can increase bone turnover and osteoclast activity, resulting in net bone loss and decreased bone quality. Inhibition of aromatase by mitapivat may have some clinical implications, as patients with pyruvate kinase deficiency have considerably high rate of osteopenia and osteoporosis. The long-term effect of mitapivant on bond mineral density requires further investigation. One study suggests that this off-target effect may have negligible clinical effects on adults, but may potentially have some clinical implications in developing children. •Mechanism of action (Drug A): Bupropion is a norepinephrine/dopamine-reuptake inhibitor (NDRI) that exerts its pharmacological effects by weakly inhibiting the enzymes involved in the uptake of the neurotransmitters norepinephrine and dopamine from the synaptic cleft, therefore prolonging their duration of action within the neuronal synapse and the downstream effects of these neurotransmitters. More specifically, bupropion binds to the norepinephrine transporter (NET) and the dopamine transporter (DAT). Bupropion was originally classified as an "atypical" antidepressant because it does not exert the same effects as the classical antidepressants such as Monoamine Oxidase Inhibitors (MAOIs), Tricyclic Antidepressants (TCAs), or Selective Serotonin Reuptake Inhibitors (SSRIs). While it has comparable effectiveness to typical first-line options for the treatment of depression such as SSRIs, bupropion is a unique option for the treatment of MDD as it lacks any clinically relevant serotonergic effects, typical of other mood medications, or any effects on histamine or adrenaline receptors. Lack of activity at these receptors results in a more tolerable side effect profile; bupropion is less likely to cause sexual side effects, sedation, or weight gain as compared to SSRIs or TCAs, for example. When used as an aid to smoking cessation, bupropion is thought to confer its anti-craving and anti-withdrawal effects by inhibiting dopamine reuptake, which is thought to be involved in the reward pathways associated with nicotine, and through the antagonism of the nicotinic acetylcholinergic receptor (AChR), thereby blunting the effects of nicotine. Furthermore, the stimulatory effects produced by bupropion in the central nervous system are similar to nicotine's effects, making low doses of bupropion a suitable option as a nicotine substitute. When used in combination with naltrexone in the marketed product ContraveⓇ for chronic weight management, the two components are thought to have effects on areas of the brain involved in the regulation of food intake. This includes the hypothalamus, which is involved in appetite regulation, and the mesolimbic dopamine circuit, which is involved in reward pathways. Studies have shown that the combined activity of bupropion and naltrexone increase the firing rate of hypothalamic pro-opiomelanocortin (POMC) neurons and blockade of opioid receptor-mediated POMC auto-inhibition, which are associated with a reduction in food intake and increased energy expenditure. This combination was also found to reduce food intake when injected directly into the ventral tegmental area of the mesolimbic circuit in mice, which is an area associated with the regulation of reward pathways. •Mechanism of action (Drug B): The pyruvate kinase enzyme is an ATP-generating enzyme involved in the Embden–Meyerhof glycolytic pathway: it catalyzes the conversion of phosphoenolpyruvate to pyruvate in the final step of glycolysis, generating adenosine triphosphate (ATP), which is critical for cellular maintenance and survival. One of the four isoforms of pyruvate kinase - erythrocyte pyruvate kinase or PKR - is dedicated to red blood cells (RBCs). Compared to most human cells, RBCs lack the metabolic machinery required for aerobic metabolism of glucose and generation of ATP; thus, they rely on anaerobic glycolysis for ATP production. The deficiency of ATP due to glycolytic enzyme defects leads to shortened lifespan and premature destruction of RBCs in the form of chronic hemolytic anemia and ineffective erythropoiesis. Pyruvate kinase deficiency is a rare hereditary disorder affecting RBC glycolysis, caused by mutations in PKLR, the gene encoding the RBC (PKR) and liver-specific isoforms (PKL) of pyruvate kinase. Pyruvate kinase deficiency is associated with a build-up of 2,3-disphosphoglycerate (2,3-DPG), an upstream metabolite in glycolysis, and deficient ATP levels. Erythrocyte pyruvate kinase is an allosterically regulated homotetrameric enzyme that is normally activated by fructose bisphosphate (FBP) in an allosteric fashion. Mitapivat is also an allosteric pyruvate kinase activator but binds to a different allosteric site from FBP on the PKR tetramer. This allows for the activation of both wild-type and mutant forms of erythrocyte pyruvate kinase, including those not induced by FBP. Upon binding to pyruvate kinase, mitapivat stabilizes the active tetrameric form of the enzyme and enhances its affinity for its substrate, phosphoenolpyruvate. Mitapivat upregulates erythrocyte pyruvate kinase activity, increases ATP production, and reduces levels of 2,3-DPG. •Absorption (Drug A): Bupropion is currently available in 3 distinct, but bioequivalent formulations: immediate release (IR), sustained-release (SR), and extended-release (XL). Immediate Release Formulation In humans, following oral administration of bupropion hydrochloride tablets, peak plasma bupropion concentrations are usually achieved within 2 hours. IR formulations provide a short duration of action and are therefore generally dosed three times per day. Sustained Release Formulation In humans, following oral administration of bupropion hydrochloride sustained-release tablets (SR), peak plasma concentration (Cmax) of bupropion is usually achieved within 3 hours. SR formulations provide a 12-hour extended release of medication and are therefore generally dosed twice per day. Extended Release Formulation Following single oral administration of bupropion hydrochloride extended-release tablets (XL) to healthy volunteers, the median time to peak plasma concentrations for bupropion was approximately 5 hours. The presence of food did not affect the peak concentration or area under the curve of bupropion. XL formulations provide a 24-hour extended release of medication and are therefore generally dosed once per day/ In a trial comparing chronic dosing with bupropion hydrochloride extended-release tablets (SR) 150 mg twice daily to bupropion immediate-release formulation 100 mg 3 times daily, the steady state Cmax for bupropion after bupropion hydrochloride sustained-release tablets (SR) administration was approximately 85% of those achieved after bupropion immediate-release formulation administration. Exposure (AUC) to bupropion was equivalent for both formulations. Bioequivalence was also demonstrated for all three major active metabolites (i.e., hydroxybupropion, threohydrobupropion and erythrohydrobupropion) for both Cmax and AUC. Thus, at steady state, bupropion hydrochloride sustained-release tablets (SR) given twice daily, and the immediate-release formulation of bupropion given 3 times daily, are essentially bioequivalent for both bupropion and the 3 quantitatively important metabolites. Furthermore, in a study comparing 14-day dosing with bupropion hydrochloride extended-release tablets (XL), 300 mg once-daily to the immediate-release formulation of bupropion at 100 mg 3 times daily, equivalence was demonstrated for peak plasma concentration and area under the curve for bupropion and the three metabolites (hydroxybupropion, threohydrobupropion, and erythrohydrobupropion). Additionally, in a study comparing 14-day dosing with bupropion hydrochloride extended-release tablets (XL) 300 mg once daily to the sustained-release formulation of bupropion at 150 mg 2 times daily, equivalence was demonstrated for peak plasma concentration and area under the curve for bupropion and the three metabolites. Bupropion hydrochloride extended-release tablets (SR) can be taken with or without food. Bupropion Cmax and AUC were increased by 11% to 35% and 16% to 19%, respectively, when bupropion hydrochloride extended-release tablets (SR) was administered with food to healthy volunteers in three trials. The food effect is not considered clinically significant. Following a single-dose administration of bupropion hydrochloride extended-release tablets (SR) in humans, Cmax of bupropion's metabolite hydroxybupropion occurs approximately 6 hours post-dose and is approximately 10 times the peak level of the parent drug at steady state. The elimination half-life of hydroxybupropion is approximately 20 (±5) hours and its AUC at steady state is about 17 times that of bupropion. The times to peak concentrations for the erythrohydrobupropion and threohydrobupropion metabolites are similar to that of the hydroxybupropion metabolite. However, their elimination half-lives are longer, 33(±10) and 37 (±13) hours, respectively, and steady-state AUCs are 1.5 and 7 times that of bupropion, respectively. •Absorption (Drug B): The absolute bioavailability of mitapivat after a single dose is approximately 73%. Mitapivat exposure increases dose-proportionally. Following twice-daily oral administration of mitapivat at the dose of 5 mg, 20 mg, and 50 mg, the mean (CV%) C max at steady state were 101.2 (17%) ng/mL, 389.9 (18%) ng/mL, and 935.2 (18%) ng/mL, respectively. The mean (CV%) AUC were 450.4 (28%) ng x h/mL, 1623.8 (28%) ng x h/mL, and 3591.4 (28%) ng x h/mL, respectively. The median T max values at steady state were 0.5 to 1.0 hour post-dose across the dose range of 5 mg to 50 mg twice daily. In healthy subjects, a high-fat meal did not affect the drug exposure but reduced the rate of mitapivat absorption, with a 42% reduction in C max and a delay in T max of 2.3 hours when compared to dosing under fasted conditions. •Volume of distribution (Drug A): No volume of distribution available •Volume of distribution (Drug B): The mean volume of distribution at steady state (V ss ) was 42.5 L. •Protein binding (Drug A): In vitro tests show that bupropion is 84% bound to human plasma proteins at concentrations up to 200 mcg per mL. The extent of protein binding of the hydroxybupropion metabolite is similar to that for bupropion, whereas the extent of protein binding of the threohydrobupropion metabolite is about half that seen with bupropion. •Protein binding (Drug B): Mitapivat is 97.7% bound to plasma proteins, with an RBC-to-plasma ratio of 0.37. •Metabolism (Drug A): Bupropion is extensively metabolized in humans. Three metabolites are active: hydroxybupropion, which is formed via hydroxylation of the tert-butyl group of bupropion, and the amino-alcohol isomers, threohydrobupropion and erythrohydrobupropion, which are formed via reduction of the carbonyl group. In vitro findings suggest that CYP2B6 is the principal isoenzyme involved in the formation of hydroxybupropion, while cytochrome P450 enzymes are not involved in the formation of threohydrobupropion. Hydroxybupropion has been shown to have the same affinity as bupropion for the norepinephrine transporter (NET) but approximately 50% of its antidepressant activity despite reaching concentrations of ~10-fold higher than that of the parent drug. Oxidation of the bupropion side chain results in the formation of a glycine conjugate of meta-chlorobenzoic acid, which is then excreted as the major urinary metabolite. The potency and toxicity of the metabolites relative to bupropion have not been fully characterized. However, it has been demonstrated in an antidepressant screening test in mice that hydroxybupropion is one-half as potent as bupropion, while threohydrobupropion and erythrohydrobupropion are 5-fold less potent than bupropion. This may be of clinical importance because the plasma concentrations of the metabolites are as high as or higher than those of bupropion. Bupropion and its metabolites exhibit linear kinetics following chronic administration of 300 to 450 mg per day. •Metabolism (Drug B): According to in vitro studies, mitapivat is primarily metabolized by CYP3A4. It is also a substrate of CYP1A2, CYP2C8, and CYP2C9. Following a single oral dose administration of 120 mg of radiolabeled mitapivat in healthy subjects, unchanged mitapivat was the major circulating component in plasma. •Route of elimination (Drug A): Bupropion is extensively metabolized in humans. Oxidation of the bupropion side chain results in the formation of a glycine conjugate of metachlorobenzoic acid, which is then excreted as the major urinary metabolite. Following oral administration of 200 mg of 14C-bupropion in humans, 87% and 10% of the radioactive dose were recovered in the urine and feces, respectively. However, the fraction of the oral dose of bupropion excreted unchanged was only 0.5%, a finding consistent with the extensive metabolism of bupropion. •Route of elimination (Drug B): Mitapivat is primary eliminated via hepatic metabolism. After a single oral administration of radiolabeled mitapivat in healthy subjects, the total recovery of administered radioactive dose was 89.2%. About 49.6% of radioactivity was recovered in the urine with 2.6% excreted as unchanged mitapivat. About 39.6% of radioactivity was recovered in the feces with less than 1% being the unchanged drug. •Half-life (Drug A): 24 hours •Half-life (Drug B): In patients with pyruvate kinase deficiency receiving multiple doses of 5 mg mitapivat twice daily to 20 mg twice daily, the mean effective half-life (t 1/2 ) of mitapivat ranged from 3 to 5 hours. •Clearance (Drug A): No clearance available •Clearance (Drug B): Population pharmacokinetics derived median CL/F at steady state was 11.5, 12.7, and 14.4 L/h for the 5 mg twice daily, 20 mg twice daily, and 50 mg twice daily regimens, respectively. •Toxicity (Drug A): Symptoms of overdose include seizures, hallucinations, loss of consciousness, tachycardia, and cardiac arrest. •Toxicity (Drug B): There is no information available regarding the LD 50 and overdose profile of mitapivat. •Brand Names (Drug A): Aplenzin, Auvelity, Budeprion, Contrave, Forfivo, Wellbutrin, Zyban •Brand Names (Drug B): Pyrukynd 5 Mg 4-week •Synonyms (Drug A): No synonyms listed •Synonyms (Drug B): No synonyms listed •Summary (Drug A): Bupropion is a norepinephrine and dopamine reuptake inhibitor used in the treatment of major depressive disorder (MDD), seasonal affective disorder (SAD), and as an aid to smoking cessation. •Summary (Drug B): Mitapivat is a pyruvate kinase activator used to treat hemolytic anemia in adults with pyruvate kinase (PK) deficiency.

When a CYP2B6 substrate is administered concurrently with a CYP2B6 inducer of unknown strength, the CYP2B6 mediated metabolism of the substrate will subsequently be enhanced - either slightly, moderately, or greatly. Such increases in metabolism consequently result in decreases in the substrate's serum concentration and/or therapeutic effect. The severity of the interaction is moderate.

Question: Does Bupropion and Mitapivat interact? Information: •Drug A: Bupropion •Drug B: Mitapivat •Severity: MODERATE •Description: The metabolism of Bupropion can be increased when combined with Mitapivat. •Extended Description: When a CYP2B6 substrate is administered concurrently with a CYP2B6 inducer of unknown strength, the CYP2B6 mediated metabolism of the substrate will subsequently be enhanced - either slightly, moderately, or greatly. Such increases in metabolism consequently result in decreases in the substrate's serum concentration and/or therapeutic effect. •Indication (Drug A): Bupropion is indicated for the treatment of major depressive disorder (MDD), seasonal affective disorder (SAD), and as an aid to smoking cessation. When used in combination with naltrexone as the marketed product ContraveⓇ, bupropion is indicated as an adjunct to a reduced-calorie diet and increased physical activity for chronic weight management in adults with an initial body mass index (BMI) of: 30 kg/m^2 or greater (obese) or 27 kg/m^2 or greater (overweight) in the presence of at least one weight-related comorbid condition (e.g., hypertension, type 2 diabetes mellitus, or dyslipidemia). Bupropion is also used off-label as a first-line treatment in patients with ADHD and comorbid bipolar disorder when used as an adjunct to mood stabilizers. •Indication (Drug B): Mitapivat is indicated for the treatment of hemolytic anemia in adults with pyruvate kinase (PK) deficiency. •Pharmacodynamics (Drug A): Bupropion is chemically unrelated to tricyclic, tetracyclic, selective serotonin re-uptake inhibitors, or other known antidepressant agents. Compared to classical tricyclic antidepressants, Bupropion is a relatively weak inhibitor of the neuronal uptake of norepinephrine and dopamine. In addition, Bupropion does not inhibit monoamine oxidase. Bupropion has been found to be essentially inactive at the serotonin transporter (SERT)(IC50 >10 000 nM), however both bupropion and its primary metabolite hydroxybupropion have been found to block the function of cation-selective serotonin type 3A receptors (5-HT3ARs). Bupropion produces dose-related central nervous system (CNS) stimulant effects in animals, as evidenced by increased locomotor activity, increased rates of responding in various schedule-controlled operant behaviour tasks, and, at high doses, induction of mild stereotyped behaviour. Due to these stimulant effects and selective activity at dopamine and norepinephrine receptors, bupropion has been identified as having an abuse potential. Bupropion has a similar structure to the controlled substance Cathinone, and has been identified as having mild amphetamine-like activity, particularly when inhaled or injected. Bupropion is also known to lower the seizure threshold, making any pre-existing seizure conditions a contraindication to its use. This risk is exacerbated when bupropion is combined with other drugs or substances that lower the seizure threshold, such as cocaine, or in clinical situations that would increase the risk of a seizure such as abrupt alcohol or benzodiazepine withdrawal. As norepinephrine has been shown to have anticonvulsant properties, bupropion's inhibitory effects on NET are thought to contribute to its pro-convulsant activity. Bupropion has been shown to increase blood pressure and pose a risk for exacerbation of unmanaged or pre-existing hypertension, however, clinical trials of bupropion in smokers with CVD have not identified an increased incidence of CV events including stroke or heart attack. In clinical trials, the mean increase in systolic blood pressure associated with the use of bupropion was found to be 1.3 mmHg. •Pharmacodynamics (Drug B): Mitapivat is a pyruvate kinase activator that works to increase the activity of erythrocyte pyruvate kinase, an enzyme responsible for energy production for and survival of red blood cells. It is effective in upregulating the activity of both wild-type and mutant forms of erythrocyte pyruvate kinase. Interestingly, mitapivat is a mild-to-moderate inhibitor of the aromatase enzyme (CYP19A1), which is an enzyme involved in biosynthesis of estrogens from androgen precursors. Inhibition of aromatase is associated with bone density loss, as estrogen mediates suppressive, antiresorptive effects on osteoclasts and generally favours bone formation over resorption. Thus, low estrogen levels can increase bone turnover and osteoclast activity, resulting in net bone loss and decreased bone quality. Inhibition of aromatase by mitapivat may have some clinical implications, as patients with pyruvate kinase deficiency have considerably high rate of osteopenia and osteoporosis. The long-term effect of mitapivant on bond mineral density requires further investigation. One study suggests that this off-target effect may have negligible clinical effects on adults, but may potentially have some clinical implications in developing children. •Mechanism of action (Drug A): Bupropion is a norepinephrine/dopamine-reuptake inhibitor (NDRI) that exerts its pharmacological effects by weakly inhibiting the enzymes involved in the uptake of the neurotransmitters norepinephrine and dopamine from the synaptic cleft, therefore prolonging their duration of action within the neuronal synapse and the downstream effects of these neurotransmitters. More specifically, bupropion binds to the norepinephrine transporter (NET) and the dopamine transporter (DAT). Bupropion was originally classified as an "atypical" antidepressant because it does not exert the same effects as the classical antidepressants such as Monoamine Oxidase Inhibitors (MAOIs), Tricyclic Antidepressants (TCAs), or Selective Serotonin Reuptake Inhibitors (SSRIs). While it has comparable effectiveness to typical first-line options for the treatment of depression such as SSRIs, bupropion is a unique option for the treatment of MDD as it lacks any clinically relevant serotonergic effects, typical of other mood medications, or any effects on histamine or adrenaline receptors. Lack of activity at these receptors results in a more tolerable side effect profile; bupropion is less likely to cause sexual side effects, sedation, or weight gain as compared to SSRIs or TCAs, for example. When used as an aid to smoking cessation, bupropion is thought to confer its anti-craving and anti-withdrawal effects by inhibiting dopamine reuptake, which is thought to be involved in the reward pathways associated with nicotine, and through the antagonism of the nicotinic acetylcholinergic receptor (AChR), thereby blunting the effects of nicotine. Furthermore, the stimulatory effects produced by bupropion in the central nervous system are similar to nicotine's effects, making low doses of bupropion a suitable option as a nicotine substitute. When used in combination with naltrexone in the marketed product ContraveⓇ for chronic weight management, the two components are thought to have effects on areas of the brain involved in the regulation of food intake. This includes the hypothalamus, which is involved in appetite regulation, and the mesolimbic dopamine circuit, which is involved in reward pathways. Studies have shown that the combined activity of bupropion and naltrexone increase the firing rate of hypothalamic pro-opiomelanocortin (POMC) neurons and blockade of opioid receptor-mediated POMC auto-inhibition, which are associated with a reduction in food intake and increased energy expenditure. This combination was also found to reduce food intake when injected directly into the ventral tegmental area of the mesolimbic circuit in mice, which is an area associated with the regulation of reward pathways. •Mechanism of action (Drug B): The pyruvate kinase enzyme is an ATP-generating enzyme involved in the Embden–Meyerhof glycolytic pathway: it catalyzes the conversion of phosphoenolpyruvate to pyruvate in the final step of glycolysis, generating adenosine triphosphate (ATP), which is critical for cellular maintenance and survival. One of the four isoforms of pyruvate kinase - erythrocyte pyruvate kinase or PKR - is dedicated to red blood cells (RBCs). Compared to most human cells, RBCs lack the metabolic machinery required for aerobic metabolism of glucose and generation of ATP; thus, they rely on anaerobic glycolysis for ATP production. The deficiency of ATP due to glycolytic enzyme defects leads to shortened lifespan and premature destruction of RBCs in the form of chronic hemolytic anemia and ineffective erythropoiesis. Pyruvate kinase deficiency is a rare hereditary disorder affecting RBC glycolysis, caused by mutations in PKLR, the gene encoding the RBC (PKR) and liver-specific isoforms (PKL) of pyruvate kinase. Pyruvate kinase deficiency is associated with a build-up of 2,3-disphosphoglycerate (2,3-DPG), an upstream metabolite in glycolysis, and deficient ATP levels. Erythrocyte pyruvate kinase is an allosterically regulated homotetrameric enzyme that is normally activated by fructose bisphosphate (FBP) in an allosteric fashion. Mitapivat is also an allosteric pyruvate kinase activator but binds to a different allosteric site from FBP on the PKR tetramer. This allows for the activation of both wild-type and mutant forms of erythrocyte pyruvate kinase, including those not induced by FBP. Upon binding to pyruvate kinase, mitapivat stabilizes the active tetrameric form of the enzyme and enhances its affinity for its substrate, phosphoenolpyruvate. Mitapivat upregulates erythrocyte pyruvate kinase activity, increases ATP production, and reduces levels of 2,3-DPG. •Absorption (Drug A): Bupropion is currently available in 3 distinct, but bioequivalent formulations: immediate release (IR), sustained-release (SR), and extended-release (XL). Immediate Release Formulation In humans, following oral administration of bupropion hydrochloride tablets, peak plasma bupropion concentrations are usually achieved within 2 hours. IR formulations provide a short duration of action and are therefore generally dosed three times per day. Sustained Release Formulation In humans, following oral administration of bupropion hydrochloride sustained-release tablets (SR), peak plasma concentration (Cmax) of bupropion is usually achieved within 3 hours. SR formulations provide a 12-hour extended release of medication and are therefore generally dosed twice per day. Extended Release Formulation Following single oral administration of bupropion hydrochloride extended-release tablets (XL) to healthy volunteers, the median time to peak plasma concentrations for bupropion was approximately 5 hours. The presence of food did not affect the peak concentration or area under the curve of bupropion. XL formulations provide a 24-hour extended release of medication and are therefore generally dosed once per day/ In a trial comparing chronic dosing with bupropion hydrochloride extended-release tablets (SR) 150 mg twice daily to bupropion immediate-release formulation 100 mg 3 times daily, the steady state Cmax for bupropion after bupropion hydrochloride sustained-release tablets (SR) administration was approximately 85% of those achieved after bupropion immediate-release formulation administration. Exposure (AUC) to bupropion was equivalent for both formulations. Bioequivalence was also demonstrated for all three major active metabolites (i.e., hydroxybupropion, threohydrobupropion and erythrohydrobupropion) for both Cmax and AUC. Thus, at steady state, bupropion hydrochloride sustained-release tablets (SR) given twice daily, and the immediate-release formulation of bupropion given 3 times daily, are essentially bioequivalent for both bupropion and the 3 quantitatively important metabolites. Furthermore, in a study comparing 14-day dosing with bupropion hydrochloride extended-release tablets (XL), 300 mg once-daily to the immediate-release formulation of bupropion at 100 mg 3 times daily, equivalence was demonstrated for peak plasma concentration and area under the curve for bupropion and the three metabolites (hydroxybupropion, threohydrobupropion, and erythrohydrobupropion). Additionally, in a study comparing 14-day dosing with bupropion hydrochloride extended-release tablets (XL) 300 mg once daily to the sustained-release formulation of bupropion at 150 mg 2 times daily, equivalence was demonstrated for peak plasma concentration and area under the curve for bupropion and the three metabolites. Bupropion hydrochloride extended-release tablets (SR) can be taken with or without food. Bupropion Cmax and AUC were increased by 11% to 35% and 16% to 19%, respectively, when bupropion hydrochloride extended-release tablets (SR) was administered with food to healthy volunteers in three trials. The food effect is not considered clinically significant. Following a single-dose administration of bupropion hydrochloride extended-release tablets (SR) in humans, Cmax of bupropion's metabolite hydroxybupropion occurs approximately 6 hours post-dose and is approximately 10 times the peak level of the parent drug at steady state. The elimination half-life of hydroxybupropion is approximately 20 (±5) hours and its AUC at steady state is about 17 times that of bupropion. The times to peak concentrations for the erythrohydrobupropion and threohydrobupropion metabolites are similar to that of the hydroxybupropion metabolite. However, their elimination half-lives are longer, 33(±10) and 37 (±13) hours, respectively, and steady-state AUCs are 1.5 and 7 times that of bupropion, respectively. •Absorption (Drug B): The absolute bioavailability of mitapivat after a single dose is approximately 73%. Mitapivat exposure increases dose-proportionally. Following twice-daily oral administration of mitapivat at the dose of 5 mg, 20 mg, and 50 mg, the mean (CV%) C max at steady state were 101.2 (17%) ng/mL, 389.9 (18%) ng/mL, and 935.2 (18%) ng/mL, respectively. The mean (CV%) AUC were 450.4 (28%) ng x h/mL, 1623.8 (28%) ng x h/mL, and 3591.4 (28%) ng x h/mL, respectively. The median T max values at steady state were 0.5 to 1.0 hour post-dose across the dose range of 5 mg to 50 mg twice daily. In healthy subjects, a high-fat meal did not affect the drug exposure but reduced the rate of mitapivat absorption, with a 42% reduction in C max and a delay in T max of 2.3 hours when compared to dosing under fasted conditions. •Volume of distribution (Drug A): No volume of distribution available •Volume of distribution (Drug B): The mean volume of distribution at steady state (V ss ) was 42.5 L. •Protein binding (Drug A): In vitro tests show that bupropion is 84% bound to human plasma proteins at concentrations up to 200 mcg per mL. The extent of protein binding of the hydroxybupropion metabolite is similar to that for bupropion, whereas the extent of protein binding of the threohydrobupropion metabolite is about half that seen with bupropion. •Protein binding (Drug B): Mitapivat is 97.7% bound to plasma proteins, with an RBC-to-plasma ratio of 0.37. •Metabolism (Drug A): Bupropion is extensively metabolized in humans. Three metabolites are active: hydroxybupropion, which is formed via hydroxylation of the tert-butyl group of bupropion, and the amino-alcohol isomers, threohydrobupropion and erythrohydrobupropion, which are formed via reduction of the carbonyl group. In vitro findings suggest that CYP2B6 is the principal isoenzyme involved in the formation of hydroxybupropion, while cytochrome P450 enzymes are not involved in the formation of threohydrobupropion. Hydroxybupropion has been shown to have the same affinity as bupropion for the norepinephrine transporter (NET) but approximately 50% of its antidepressant activity despite reaching concentrations of ~10-fold higher than that of the parent drug. Oxidation of the bupropion side chain results in the formation of a glycine conjugate of meta-chlorobenzoic acid, which is then excreted as the major urinary metabolite. The potency and toxicity of the metabolites relative to bupropion have not been fully characterized. However, it has been demonstrated in an antidepressant screening test in mice that hydroxybupropion is one-half as potent as bupropion, while threohydrobupropion and erythrohydrobupropion are 5-fold less potent than bupropion. This may be of clinical importance because the plasma concentrations of the metabolites are as high as or higher than those of bupropion. Bupropion and its metabolites exhibit linear kinetics following chronic administration of 300 to 450 mg per day. •Metabolism (Drug B): According to in vitro studies, mitapivat is primarily metabolized by CYP3A4. It is also a substrate of CYP1A2, CYP2C8, and CYP2C9. Following a single oral dose administration of 120 mg of radiolabeled mitapivat in healthy subjects, unchanged mitapivat was the major circulating component in plasma. •Route of elimination (Drug A): Bupropion is extensively metabolized in humans. Oxidation of the bupropion side chain results in the formation of a glycine conjugate of metachlorobenzoic acid, which is then excreted as the major urinary metabolite. Following oral administration of 200 mg of 14C-bupropion in humans, 87% and 10% of the radioactive dose were recovered in the urine and feces, respectively. However, the fraction of the oral dose of bupropion excreted unchanged was only 0.5%, a finding consistent with the extensive metabolism of bupropion. •Route of elimination (Drug B): Mitapivat is primary eliminated via hepatic metabolism. After a single oral administration of radiolabeled mitapivat in healthy subjects, the total recovery of administered radioactive dose was 89.2%. About 49.6% of radioactivity was recovered in the urine with 2.6% excreted as unchanged mitapivat. About 39.6% of radioactivity was recovered in the feces with less than 1% being the unchanged drug. •Half-life (Drug A): 24 hours •Half-life (Drug B): In patients with pyruvate kinase deficiency receiving multiple doses of 5 mg mitapivat twice daily to 20 mg twice daily, the mean effective half-life (t 1/2 ) of mitapivat ranged from 3 to 5 hours. •Clearance (Drug A): No clearance available •Clearance (Drug B): Population pharmacokinetics derived median CL/F at steady state was 11.5, 12.7, and 14.4 L/h for the 5 mg twice daily, 20 mg twice daily, and 50 mg twice daily regimens, respectively. •Toxicity (Drug A): Symptoms of overdose include seizures, hallucinations, loss of consciousness, tachycardia, and cardiac arrest. •Toxicity (Drug B): There is no information available regarding the LD 50 and overdose profile of mitapivat. •Brand Names (Drug A): Aplenzin, Auvelity, Budeprion, Contrave, Forfivo, Wellbutrin, Zyban •Brand Names (Drug B): Pyrukynd 5 Mg 4-week •Synonyms (Drug A): No synonyms listed •Synonyms (Drug B): No synonyms listed •Summary (Drug A): Bupropion is a norepinephrine and dopamine reuptake inhibitor used in the treatment of major depressive disorder (MDD), seasonal affective disorder (SAD), and as an aid to smoking cessation. •Summary (Drug B): Mitapivat is a pyruvate kinase activator used to treat hemolytic anemia in adults with pyruvate kinase (PK) deficiency. Output: When a CYP2B6 substrate is administered concurrently with a CYP2B6 inducer of unknown strength, the CYP2B6 mediated metabolism of the substrate will subsequently be enhanced - either slightly, moderately, or greatly. Such increases in metabolism consequently result in decreases in the substrate's serum concentration and/or therapeutic effect. The severity of the interaction is moderate.

Does Bupropion and Mivacurium interact?

•Drug A: Bupropion •Drug B: Mivacurium •Severity: MODERATE •Description: The risk or severity of CNS depression can be increased when Bupropion is combined with Mivacurium. •Extended Description: Central nervous system (CNS) depressants can cause sedation, falls, respiratory depression, coma, and death.2,3 The potential interaction between a CNS depressant and another CNS depressant drug due to synergistic effects is well documented in the literature, although the risk and severity of CNS depression vary from each drug. The subject and affected drugs are both CNS depressants that, when co-administered, may result in a more profound CNS depression. As the risk and severity of CNS depression resulting from the combined use of CNS depressants vary from each agent, each interaction between CNS depressants should be considered individually. •Indication (Drug A): Bupropion is indicated for the treatment of major depressive disorder (MDD), seasonal affective disorder (SAD), and as an aid to smoking cessation. When used in combination with naltrexone as the marketed product ContraveⓇ, bupropion is indicated as an adjunct to a reduced-calorie diet and increased physical activity for chronic weight management in adults with an initial body mass index (BMI) of: 30 kg/m^2 or greater (obese) or 27 kg/m^2 or greater (overweight) in the presence of at least one weight-related comorbid condition (e.g., hypertension, type 2 diabetes mellitus, or dyslipidemia). Bupropion is also used off-label as a first-line treatment in patients with ADHD and comorbid bipolar disorder when used as an adjunct to mood stabilizers. •Indication (Drug B): For inpatients and outpatients, as an adjunct to general anesthesia, to facilitate tracheal intubation and to provide skeletal muscle relaxation during surgery or mechanical ventilation. •Pharmacodynamics (Drug A): Bupropion is chemically unrelated to tricyclic, tetracyclic, selective serotonin re-uptake inhibitors, or other known antidepressant agents. Compared to classical tricyclic antidepressants, Bupropion is a relatively weak inhibitor of the neuronal uptake of norepinephrine and dopamine. In addition, Bupropion does not inhibit monoamine oxidase. Bupropion has been found to be essentially inactive at the serotonin transporter (SERT)(IC50 >10 000 nM), however both bupropion and its primary metabolite hydroxybupropion have been found to block the function of cation-selective serotonin type 3A receptors (5-HT3ARs). Bupropion produces dose-related central nervous system (CNS) stimulant effects in animals, as evidenced by increased locomotor activity, increased rates of responding in various schedule-controlled operant behaviour tasks, and, at high doses, induction of mild stereotyped behaviour. Due to these stimulant effects and selective activity at dopamine and norepinephrine receptors, bupropion has been identified as having an abuse potential. Bupropion has a similar structure to the controlled substance Cathinone, and has been identified as having mild amphetamine-like activity, particularly when inhaled or injected. Bupropion is also known to lower the seizure threshold, making any pre-existing seizure conditions a contraindication to its use. This risk is exacerbated when bupropion is combined with other drugs or substances that lower the seizure threshold, such as cocaine, or in clinical situations that would increase the risk of a seizure such as abrupt alcohol or benzodiazepine withdrawal. As norepinephrine has been shown to have anticonvulsant properties, bupropion's inhibitory effects on NET are thought to contribute to its pro-convulsant activity. Bupropion has been shown to increase blood pressure and pose a risk for exacerbation of unmanaged or pre-existing hypertension, however, clinical trials of bupropion in smokers with CVD have not identified an increased incidence of CV events including stroke or heart attack. In clinical trials, the mean increase in systolic blood pressure associated with the use of bupropion was found to be 1.3 mmHg. •Pharmacodynamics (Drug B): Mivacurium is a short-acting, nondepolarizing skeletal neuromuscular blocking agent which is hydrolyzed by plasma cholinesterase. Mivacurium results in a blockade of neuromuscular transmission by binding competitively with cholinergic receptors on the motor end-plate to antagonize the action of acetylcholine. The neuromuscular block produced by mivacurium is readily antagonized by anticholinesterase agents. The deeper the level of neuromuscular block at reversal, the longer the time required for recovery of neuromuscular function and the greater the dose of anticholinesterase agent required. Because spontaneous recovery after mivacurium is rapid, routine reversal may not always result in a clinical benefit. •Mechanism of action (Drug A): Bupropion is a norepinephrine/dopamine-reuptake inhibitor (NDRI) that exerts its pharmacological effects by weakly inhibiting the enzymes involved in the uptake of the neurotransmitters norepinephrine and dopamine from the synaptic cleft, therefore prolonging their duration of action within the neuronal synapse and the downstream effects of these neurotransmitters. More specifically, bupropion binds to the norepinephrine transporter (NET) and the dopamine transporter (DAT). Bupropion was originally classified as an "atypical" antidepressant because it does not exert the same effects as the classical antidepressants such as Monoamine Oxidase Inhibitors (MAOIs), Tricyclic Antidepressants (TCAs), or Selective Serotonin Reuptake Inhibitors (SSRIs). While it has comparable effectiveness to typical first-line options for the treatment of depression such as SSRIs, bupropion is a unique option for the treatment of MDD as it lacks any clinically relevant serotonergic effects, typical of other mood medications, or any effects on histamine or adrenaline receptors. Lack of activity at these receptors results in a more tolerable side effect profile; bupropion is less likely to cause sexual side effects, sedation, or weight gain as compared to SSRIs or TCAs, for example. When used as an aid to smoking cessation, bupropion is thought to confer its anti-craving and anti-withdrawal effects by inhibiting dopamine reuptake, which is thought to be involved in the reward pathways associated with nicotine, and through the antagonism of the nicotinic acetylcholinergic receptor (AChR), thereby blunting the effects of nicotine. Furthermore, the stimulatory effects produced by bupropion in the central nervous system are similar to nicotine's effects, making low doses of bupropion a suitable option as a nicotine substitute. When used in combination with naltrexone in the marketed product ContraveⓇ for chronic weight management, the two components are thought to have effects on areas of the brain involved in the regulation of food intake. This includes the hypothalamus, which is involved in appetite regulation, and the mesolimbic dopamine circuit, which is involved in reward pathways. Studies have shown that the combined activity of bupropion and naltrexone increase the firing rate of hypothalamic pro-opiomelanocortin (POMC) neurons and blockade of opioid receptor-mediated POMC auto-inhibition, which are associated with a reduction in food intake and increased energy expenditure. This combination was also found to reduce food intake when injected directly into the ventral tegmental area of the mesolimbic circuit in mice, which is an area associated with the regulation of reward pathways. •Mechanism of action (Drug B): Mivacurium binds competitively to cholinergic receptors on the motor end-plate to antagonize the action of acetylcholine, resulting in a block of neuromuscular transmission. This action is antagonized by acetylcholinesterase inhibitors, such as neostigmine. •Absorption (Drug A): Bupropion is currently available in 3 distinct, but bioequivalent formulations: immediate release (IR), sustained-release (SR), and extended-release (XL). Immediate Release Formulation In humans, following oral administration of bupropion hydrochloride tablets, peak plasma bupropion concentrations are usually achieved within 2 hours. IR formulations provide a short duration of action and are therefore generally dosed three times per day. Sustained Release Formulation In humans, following oral administration of bupropion hydrochloride sustained-release tablets (SR), peak plasma concentration (Cmax) of bupropion is usually achieved within 3 hours. SR formulations provide a 12-hour extended release of medication and are therefore generally dosed twice per day. Extended Release Formulation Following single oral administration of bupropion hydrochloride extended-release tablets (XL) to healthy volunteers, the median time to peak plasma concentrations for bupropion was approximately 5 hours. The presence of food did not affect the peak concentration or area under the curve of bupropion. XL formulations provide a 24-hour extended release of medication and are therefore generally dosed once per day/ In a trial comparing chronic dosing with bupropion hydrochloride extended-release tablets (SR) 150 mg twice daily to bupropion immediate-release formulation 100 mg 3 times daily, the steady state Cmax for bupropion after bupropion hydrochloride sustained-release tablets (SR) administration was approximately 85% of those achieved after bupropion immediate-release formulation administration. Exposure (AUC) to bupropion was equivalent for both formulations. Bioequivalence was also demonstrated for all three major active metabolites (i.e., hydroxybupropion, threohydrobupropion and erythrohydrobupropion) for both Cmax and AUC. Thus, at steady state, bupropion hydrochloride sustained-release tablets (SR) given twice daily, and the immediate-release formulation of bupropion given 3 times daily, are essentially bioequivalent for both bupropion and the 3 quantitatively important metabolites. Furthermore, in a study comparing 14-day dosing with bupropion hydrochloride extended-release tablets (XL), 300 mg once-daily to the immediate-release formulation of bupropion at 100 mg 3 times daily, equivalence was demonstrated for peak plasma concentration and area under the curve for bupropion and the three metabolites (hydroxybupropion, threohydrobupropion, and erythrohydrobupropion). Additionally, in a study comparing 14-day dosing with bupropion hydrochloride extended-release tablets (XL) 300 mg once daily to the sustained-release formulation of bupropion at 150 mg 2 times daily, equivalence was demonstrated for peak plasma concentration and area under the curve for bupropion and the three metabolites. Bupropion hydrochloride extended-release tablets (SR) can be taken with or without food. Bupropion Cmax and AUC were increased by 11% to 35% and 16% to 19%, respectively, when bupropion hydrochloride extended-release tablets (SR) was administered with food to healthy volunteers in three trials. The food effect is not considered clinically significant. Following a single-dose administration of bupropion hydrochloride extended-release tablets (SR) in humans, Cmax of bupropion's metabolite hydroxybupropion occurs approximately 6 hours post-dose and is approximately 10 times the peak level of the parent drug at steady state. The elimination half-life of hydroxybupropion is approximately 20 (±5) hours and its AUC at steady state is about 17 times that of bupropion. The times to peak concentrations for the erythrohydrobupropion and threohydrobupropion metabolites are similar to that of the hydroxybupropion metabolite. However, their elimination half-lives are longer, 33(±10) and 37 (±13) hours, respectively, and steady-state AUCs are 1.5 and 7 times that of bupropion, respectively. •Absorption (Drug B): No absorption available •Volume of distribution (Drug A): No volume of distribution available •Volume of distribution (Drug B): No volume of distribution available •Protein binding (Drug A): In vitro tests show that bupropion is 84% bound to human plasma proteins at concentrations up to 200 mcg per mL. The extent of protein binding of the hydroxybupropion metabolite is similar to that for bupropion, whereas the extent of protein binding of the threohydrobupropion metabolite is about half that seen with bupropion. •Protein binding (Drug B): The protein binding of mivacurium has not been determined due to its rapid hydrolysis by plasma cholinesterase. •Metabolism (Drug A): Bupropion is extensively metabolized in humans. Three metabolites are active: hydroxybupropion, which is formed via hydroxylation of the tert-butyl group of bupropion, and the amino-alcohol isomers, threohydrobupropion and erythrohydrobupropion, which are formed via reduction of the carbonyl group. In vitro findings suggest that CYP2B6 is the principal isoenzyme involved in the formation of hydroxybupropion, while cytochrome P450 enzymes are not involved in the formation of threohydrobupropion. Hydroxybupropion has been shown to have the same affinity as bupropion for the norepinephrine transporter (NET) but approximately 50% of its antidepressant activity despite reaching concentrations of ~10-fold higher than that of the parent drug. Oxidation of the bupropion side chain results in the formation of a glycine conjugate of meta-chlorobenzoic acid, which is then excreted as the major urinary metabolite. The potency and toxicity of the metabolites relative to bupropion have not been fully characterized. However, it has been demonstrated in an antidepressant screening test in mice that hydroxybupropion is one-half as potent as bupropion, while threohydrobupropion and erythrohydrobupropion are 5-fold less potent than bupropion. This may be of clinical importance because the plasma concentrations of the metabolites are as high as or higher than those of bupropion. Bupropion and its metabolites exhibit linear kinetics following chronic administration of 300 to 450 mg per day. •Metabolism (Drug B): Extensive and rapid via enzymatic hydrolysis catalyzed by plasma cholinesterase. Biotransformation may be significantly slowed in patients with abnormal or decreased plasma cholinesterase activity, especially individuals with a homozygous atypical cholinesterase gene abnormality. •Route of elimination (Drug A): Bupropion is extensively metabolized in humans. Oxidation of the bupropion side chain results in the formation of a glycine conjugate of metachlorobenzoic acid, which is then excreted as the major urinary metabolite. Following oral administration of 200 mg of 14C-bupropion in humans, 87% and 10% of the radioactive dose were recovered in the urine and feces, respectively. However, the fraction of the oral dose of bupropion excreted unchanged was only 0.5%, a finding consistent with the extensive metabolism of bupropion. •Route of elimination (Drug B): No route of elimination available •Half-life (Drug A): 24 hours •Half-life (Drug B): The mean elimination half-life ranges from 1.7 to 2.6 minutes in healthy, young adults administered 0.1 to 0.25 mg/kg mivacurium. In 9 patients with end-stage liver disease undergoing liver transplant surgery, plasma clearance was approximately 50% lower than that in 8 control patients with normal hepatic function, while the elimination half-life increased to 4.4 minutes from the 1.8 minute control value. •Clearance (Drug A): No clearance available •Clearance (Drug B): No clearance available •Toxicity (Drug A): Symptoms of overdose include seizures, hallucinations, loss of consciousness, tachycardia, and cardiac arrest. •Toxicity (Drug B): Overdosage with neuromuscular blocking agents may result in neuromuscular block beyond the time needed for surgery and anesthesia. •Brand Names (Drug A): Aplenzin, Auvelity, Budeprion, Contrave, Forfivo, Wellbutrin, Zyban •Brand Names (Drug B): No brand names available •Synonyms (Drug A): No synonyms listed •Synonyms (Drug B): No synonyms listed •Summary (Drug A): Bupropion is a norepinephrine and dopamine reuptake inhibitor used in the treatment of major depressive disorder (MDD), seasonal affective disorder (SAD), and as an aid to smoking cessation. •Summary (Drug B): Mivacurium is a short-acting non-depolarizing neuromuscular blocking agent used to induce anesthesia during intubation and promote skeletal muscle relaxation during surgery or mechanical ventilation.

Central nervous system (CNS) depressants can cause sedation, falls, respiratory depression, coma, and death.2,3 The potential interaction between a CNS depressant and another CNS depressant drug due to synergistic effects is well documented in the literature, although the risk and severity of CNS depression vary from each drug. The subject and affected drugs are both CNS depressants that, when co-administered, may result in a more profound CNS depression. As the risk and severity of CNS depression resulting from the combined use of CNS depressants vary from each agent, each interaction between CNS depressants should be considered individually. The severity of the interaction is moderate.

Question: Does Bupropion and Mivacurium interact? Information: •Drug A: Bupropion •Drug B: Mivacurium •Severity: MODERATE •Description: The risk or severity of CNS depression can be increased when Bupropion is combined with Mivacurium. •Extended Description: Central nervous system (CNS) depressants can cause sedation, falls, respiratory depression, coma, and death.2,3 The potential interaction between a CNS depressant and another CNS depressant drug due to synergistic effects is well documented in the literature, although the risk and severity of CNS depression vary from each drug. The subject and affected drugs are both CNS depressants that, when co-administered, may result in a more profound CNS depression. As the risk and severity of CNS depression resulting from the combined use of CNS depressants vary from each agent, each interaction between CNS depressants should be considered individually. •Indication (Drug A): Bupropion is indicated for the treatment of major depressive disorder (MDD), seasonal affective disorder (SAD), and as an aid to smoking cessation. When used in combination with naltrexone as the marketed product ContraveⓇ, bupropion is indicated as an adjunct to a reduced-calorie diet and increased physical activity for chronic weight management in adults with an initial body mass index (BMI) of: 30 kg/m^2 or greater (obese) or 27 kg/m^2 or greater (overweight) in the presence of at least one weight-related comorbid condition (e.g., hypertension, type 2 diabetes mellitus, or dyslipidemia). Bupropion is also used off-label as a first-line treatment in patients with ADHD and comorbid bipolar disorder when used as an adjunct to mood stabilizers. •Indication (Drug B): For inpatients and outpatients, as an adjunct to general anesthesia, to facilitate tracheal intubation and to provide skeletal muscle relaxation during surgery or mechanical ventilation. •Pharmacodynamics (Drug A): Bupropion is chemically unrelated to tricyclic, tetracyclic, selective serotonin re-uptake inhibitors, or other known antidepressant agents. Compared to classical tricyclic antidepressants, Bupropion is a relatively weak inhibitor of the neuronal uptake of norepinephrine and dopamine. In addition, Bupropion does not inhibit monoamine oxidase. Bupropion has been found to be essentially inactive at the serotonin transporter (SERT)(IC50 >10 000 nM), however both bupropion and its primary metabolite hydroxybupropion have been found to block the function of cation-selective serotonin type 3A receptors (5-HT3ARs). Bupropion produces dose-related central nervous system (CNS) stimulant effects in animals, as evidenced by increased locomotor activity, increased rates of responding in various schedule-controlled operant behaviour tasks, and, at high doses, induction of mild stereotyped behaviour. Due to these stimulant effects and selective activity at dopamine and norepinephrine receptors, bupropion has been identified as having an abuse potential. Bupropion has a similar structure to the controlled substance Cathinone, and has been identified as having mild amphetamine-like activity, particularly when inhaled or injected. Bupropion is also known to lower the seizure threshold, making any pre-existing seizure conditions a contraindication to its use. This risk is exacerbated when bupropion is combined with other drugs or substances that lower the seizure threshold, such as cocaine, or in clinical situations that would increase the risk of a seizure such as abrupt alcohol or benzodiazepine withdrawal. As norepinephrine has been shown to have anticonvulsant properties, bupropion's inhibitory effects on NET are thought to contribute to its pro-convulsant activity. Bupropion has been shown to increase blood pressure and pose a risk for exacerbation of unmanaged or pre-existing hypertension, however, clinical trials of bupropion in smokers with CVD have not identified an increased incidence of CV events including stroke or heart attack. In clinical trials, the mean increase in systolic blood pressure associated with the use of bupropion was found to be 1.3 mmHg. •Pharmacodynamics (Drug B): Mivacurium is a short-acting, nondepolarizing skeletal neuromuscular blocking agent which is hydrolyzed by plasma cholinesterase. Mivacurium results in a blockade of neuromuscular transmission by binding competitively with cholinergic receptors on the motor end-plate to antagonize the action of acetylcholine. The neuromuscular block produced by mivacurium is readily antagonized by anticholinesterase agents. The deeper the level of neuromuscular block at reversal, the longer the time required for recovery of neuromuscular function and the greater the dose of anticholinesterase agent required. Because spontaneous recovery after mivacurium is rapid, routine reversal may not always result in a clinical benefit. •Mechanism of action (Drug A): Bupropion is a norepinephrine/dopamine-reuptake inhibitor (NDRI) that exerts its pharmacological effects by weakly inhibiting the enzymes involved in the uptake of the neurotransmitters norepinephrine and dopamine from the synaptic cleft, therefore prolonging their duration of action within the neuronal synapse and the downstream effects of these neurotransmitters. More specifically, bupropion binds to the norepinephrine transporter (NET) and the dopamine transporter (DAT). Bupropion was originally classified as an "atypical" antidepressant because it does not exert the same effects as the classical antidepressants such as Monoamine Oxidase Inhibitors (MAOIs), Tricyclic Antidepressants (TCAs), or Selective Serotonin Reuptake Inhibitors (SSRIs). While it has comparable effectiveness to typical first-line options for the treatment of depression such as SSRIs, bupropion is a unique option for the treatment of MDD as it lacks any clinically relevant serotonergic effects, typical of other mood medications, or any effects on histamine or adrenaline receptors. Lack of activity at these receptors results in a more tolerable side effect profile; bupropion is less likely to cause sexual side effects, sedation, or weight gain as compared to SSRIs or TCAs, for example. When used as an aid to smoking cessation, bupropion is thought to confer its anti-craving and anti-withdrawal effects by inhibiting dopamine reuptake, which is thought to be involved in the reward pathways associated with nicotine, and through the antagonism of the nicotinic acetylcholinergic receptor (AChR), thereby blunting the effects of nicotine. Furthermore, the stimulatory effects produced by bupropion in the central nervous system are similar to nicotine's effects, making low doses of bupropion a suitable option as a nicotine substitute. When used in combination with naltrexone in the marketed product ContraveⓇ for chronic weight management, the two components are thought to have effects on areas of the brain involved in the regulation of food intake. This includes the hypothalamus, which is involved in appetite regulation, and the mesolimbic dopamine circuit, which is involved in reward pathways. Studies have shown that the combined activity of bupropion and naltrexone increase the firing rate of hypothalamic pro-opiomelanocortin (POMC) neurons and blockade of opioid receptor-mediated POMC auto-inhibition, which are associated with a reduction in food intake and increased energy expenditure. This combination was also found to reduce food intake when injected directly into the ventral tegmental area of the mesolimbic circuit in mice, which is an area associated with the regulation of reward pathways. •Mechanism of action (Drug B): Mivacurium binds competitively to cholinergic receptors on the motor end-plate to antagonize the action of acetylcholine, resulting in a block of neuromuscular transmission. This action is antagonized by acetylcholinesterase inhibitors, such as neostigmine. •Absorption (Drug A): Bupropion is currently available in 3 distinct, but bioequivalent formulations: immediate release (IR), sustained-release (SR), and extended-release (XL). Immediate Release Formulation In humans, following oral administration of bupropion hydrochloride tablets, peak plasma bupropion concentrations are usually achieved within 2 hours. IR formulations provide a short duration of action and are therefore generally dosed three times per day. Sustained Release Formulation In humans, following oral administration of bupropion hydrochloride sustained-release tablets (SR), peak plasma concentration (Cmax) of bupropion is usually achieved within 3 hours. SR formulations provide a 12-hour extended release of medication and are therefore generally dosed twice per day. Extended Release Formulation Following single oral administration of bupropion hydrochloride extended-release tablets (XL) to healthy volunteers, the median time to peak plasma concentrations for bupropion was approximately 5 hours. The presence of food did not affect the peak concentration or area under the curve of bupropion. XL formulations provide a 24-hour extended release of medication and are therefore generally dosed once per day/ In a trial comparing chronic dosing with bupropion hydrochloride extended-release tablets (SR) 150 mg twice daily to bupropion immediate-release formulation 100 mg 3 times daily, the steady state Cmax for bupropion after bupropion hydrochloride sustained-release tablets (SR) administration was approximately 85% of those achieved after bupropion immediate-release formulation administration. Exposure (AUC) to bupropion was equivalent for both formulations. Bioequivalence was also demonstrated for all three major active metabolites (i.e., hydroxybupropion, threohydrobupropion and erythrohydrobupropion) for both Cmax and AUC. Thus, at steady state, bupropion hydrochloride sustained-release tablets (SR) given twice daily, and the immediate-release formulation of bupropion given 3 times daily, are essentially bioequivalent for both bupropion and the 3 quantitatively important metabolites. Furthermore, in a study comparing 14-day dosing with bupropion hydrochloride extended-release tablets (XL), 300 mg once-daily to the immediate-release formulation of bupropion at 100 mg 3 times daily, equivalence was demonstrated for peak plasma concentration and area under the curve for bupropion and the three metabolites (hydroxybupropion, threohydrobupropion, and erythrohydrobupropion). Additionally, in a study comparing 14-day dosing with bupropion hydrochloride extended-release tablets (XL) 300 mg once daily to the sustained-release formulation of bupropion at 150 mg 2 times daily, equivalence was demonstrated for peak plasma concentration and area under the curve for bupropion and the three metabolites. Bupropion hydrochloride extended-release tablets (SR) can be taken with or without food. Bupropion Cmax and AUC were increased by 11% to 35% and 16% to 19%, respectively, when bupropion hydrochloride extended-release tablets (SR) was administered with food to healthy volunteers in three trials. The food effect is not considered clinically significant. Following a single-dose administration of bupropion hydrochloride extended-release tablets (SR) in humans, Cmax of bupropion's metabolite hydroxybupropion occurs approximately 6 hours post-dose and is approximately 10 times the peak level of the parent drug at steady state. The elimination half-life of hydroxybupropion is approximately 20 (±5) hours and its AUC at steady state is about 17 times that of bupropion. The times to peak concentrations for the erythrohydrobupropion and threohydrobupropion metabolites are similar to that of the hydroxybupropion metabolite. However, their elimination half-lives are longer, 33(±10) and 37 (±13) hours, respectively, and steady-state AUCs are 1.5 and 7 times that of bupropion, respectively. •Absorption (Drug B): No absorption available •Volume of distribution (Drug A): No volume of distribution available •Volume of distribution (Drug B): No volume of distribution available •Protein binding (Drug A): In vitro tests show that bupropion is 84% bound to human plasma proteins at concentrations up to 200 mcg per mL. The extent of protein binding of the hydroxybupropion metabolite is similar to that for bupropion, whereas the extent of protein binding of the threohydrobupropion metabolite is about half that seen with bupropion. •Protein binding (Drug B): The protein binding of mivacurium has not been determined due to its rapid hydrolysis by plasma cholinesterase. •Metabolism (Drug A): Bupropion is extensively metabolized in humans. Three metabolites are active: hydroxybupropion, which is formed via hydroxylation of the tert-butyl group of bupropion, and the amino-alcohol isomers, threohydrobupropion and erythrohydrobupropion, which are formed via reduction of the carbonyl group. In vitro findings suggest that CYP2B6 is the principal isoenzyme involved in the formation of hydroxybupropion, while cytochrome P450 enzymes are not involved in the formation of threohydrobupropion. Hydroxybupropion has been shown to have the same affinity as bupropion for the norepinephrine transporter (NET) but approximately 50% of its antidepressant activity despite reaching concentrations of ~10-fold higher than that of the parent drug. Oxidation of the bupropion side chain results in the formation of a glycine conjugate of meta-chlorobenzoic acid, which is then excreted as the major urinary metabolite. The potency and toxicity of the metabolites relative to bupropion have not been fully characterized. However, it has been demonstrated in an antidepressant screening test in mice that hydroxybupropion is one-half as potent as bupropion, while threohydrobupropion and erythrohydrobupropion are 5-fold less potent than bupropion. This may be of clinical importance because the plasma concentrations of the metabolites are as high as or higher than those of bupropion. Bupropion and its metabolites exhibit linear kinetics following chronic administration of 300 to 450 mg per day. •Metabolism (Drug B): Extensive and rapid via enzymatic hydrolysis catalyzed by plasma cholinesterase. Biotransformation may be significantly slowed in patients with abnormal or decreased plasma cholinesterase activity, especially individuals with a homozygous atypical cholinesterase gene abnormality. •Route of elimination (Drug A): Bupropion is extensively metabolized in humans. Oxidation of the bupropion side chain results in the formation of a glycine conjugate of metachlorobenzoic acid, which is then excreted as the major urinary metabolite. Following oral administration of 200 mg of 14C-bupropion in humans, 87% and 10% of the radioactive dose were recovered in the urine and feces, respectively. However, the fraction of the oral dose of bupropion excreted unchanged was only 0.5%, a finding consistent with the extensive metabolism of bupropion. •Route of elimination (Drug B): No route of elimination available •Half-life (Drug A): 24 hours •Half-life (Drug B): The mean elimination half-life ranges from 1.7 to 2.6 minutes in healthy, young adults administered 0.1 to 0.25 mg/kg mivacurium. In 9 patients with end-stage liver disease undergoing liver transplant surgery, plasma clearance was approximately 50% lower than that in 8 control patients with normal hepatic function, while the elimination half-life increased to 4.4 minutes from the 1.8 minute control value. •Clearance (Drug A): No clearance available •Clearance (Drug B): No clearance available •Toxicity (Drug A): Symptoms of overdose include seizures, hallucinations, loss of consciousness, tachycardia, and cardiac arrest. •Toxicity (Drug B): Overdosage with neuromuscular blocking agents may result in neuromuscular block beyond the time needed for surgery and anesthesia. •Brand Names (Drug A): Aplenzin, Auvelity, Budeprion, Contrave, Forfivo, Wellbutrin, Zyban •Brand Names (Drug B): No brand names available •Synonyms (Drug A): No synonyms listed •Synonyms (Drug B): No synonyms listed •Summary (Drug A): Bupropion is a norepinephrine and dopamine reuptake inhibitor used in the treatment of major depressive disorder (MDD), seasonal affective disorder (SAD), and as an aid to smoking cessation. •Summary (Drug B): Mivacurium is a short-acting non-depolarizing neuromuscular blocking agent used to induce anesthesia during intubation and promote skeletal muscle relaxation during surgery or mechanical ventilation. Output: Central nervous system (CNS) depressants can cause sedation, falls, respiratory depression, coma, and death.2,3 The potential interaction between a CNS depressant and another CNS depressant drug due to synergistic effects is well documented in the literature, although the risk and severity of CNS depression vary from each drug. The subject and affected drugs are both CNS depressants that, when co-administered, may result in a more profound CNS depression. As the risk and severity of CNS depression resulting from the combined use of CNS depressants vary from each agent, each interaction between CNS depressants should be considered individually. The severity of the interaction is moderate.

Does Bupropion and Moclobemide interact?

•Drug A: Bupropion •Drug B: Moclobemide •Severity: MAJOR •Description: The risk or severity of adverse effects can be increased when Moclobemide is combined with Bupropion. •Extended Description: Bupropion is a dopaminergic agent that is used in the treatment of Parkinson's disease, depression, and smoking cessation. Based on the findings from animal studies, co-administration of bupropion with monoamine oxidase inhibitors may enhance the acute toxicity effects of bupropion, as indicated by an increase in mortality and a decrease in time to death . This interaction applies to both immediate release and sustained release forms of bupropion. •Indication (Drug A): Bupropion is indicated for the treatment of major depressive disorder (MDD), seasonal affective disorder (SAD), and as an aid to smoking cessation. When used in combination with naltrexone as the marketed product ContraveⓇ, bupropion is indicated as an adjunct to a reduced-calorie diet and increased physical activity for chronic weight management in adults with an initial body mass index (BMI) of: 30 kg/m^2 or greater (obese) or 27 kg/m^2 or greater (overweight) in the presence of at least one weight-related comorbid condition (e.g., hypertension, type 2 diabetes mellitus, or dyslipidemia). Bupropion is also used off-label as a first-line treatment in patients with ADHD and comorbid bipolar disorder when used as an adjunct to mood stabilizers. •Indication (Drug B): For the treatment of major depressive disorder and bipolar disorder. •Pharmacodynamics (Drug A): Bupropion is chemically unrelated to tricyclic, tetracyclic, selective serotonin re-uptake inhibitors, or other known antidepressant agents. Compared to classical tricyclic antidepressants, Bupropion is a relatively weak inhibitor of the neuronal uptake of norepinephrine and dopamine. In addition, Bupropion does not inhibit monoamine oxidase. Bupropion has been found to be essentially inactive at the serotonin transporter (SERT)(IC50 >10 000 nM), however both bupropion and its primary metabolite hydroxybupropion have been found to block the function of cation-selective serotonin type 3A receptors (5-HT3ARs). Bupropion produces dose-related central nervous system (CNS) stimulant effects in animals, as evidenced by increased locomotor activity, increased rates of responding in various schedule-controlled operant behaviour tasks, and, at high doses, induction of mild stereotyped behaviour. Due to these stimulant effects and selective activity at dopamine and norepinephrine receptors, bupropion has been identified as having an abuse potential. Bupropion has a similar structure to the controlled substance Cathinone, and has been identified as having mild amphetamine-like activity, particularly when inhaled or injected. Bupropion is also known to lower the seizure threshold, making any pre-existing seizure conditions a contraindication to its use. This risk is exacerbated when bupropion is combined with other drugs or substances that lower the seizure threshold, such as cocaine, or in clinical situations that would increase the risk of a seizure such as abrupt alcohol or benzodiazepine withdrawal. As norepinephrine has been shown to have anticonvulsant properties, bupropion's inhibitory effects on NET are thought to contribute to its pro-convulsant activity. Bupropion has been shown to increase blood pressure and pose a risk for exacerbation of unmanaged or pre-existing hypertension, however, clinical trials of bupropion in smokers with CVD have not identified an increased incidence of CV events including stroke or heart attack. In clinical trials, the mean increase in systolic blood pressure associated with the use of bupropion was found to be 1.3 mmHg. •Pharmacodynamics (Drug B): A selective, reversible inhibitor of monoamine oxidase (MAO) which increases the. Besides its presence in sympathetic nerves, there is an abundant evidence that MAO-A is localized in noradrenergic neurons in the locus coeruleus and MAO-B is closely associated with serotonergic neurons of the raphe nucleus. •Mechanism of action (Drug A): Bupropion is a norepinephrine/dopamine-reuptake inhibitor (NDRI) that exerts its pharmacological effects by weakly inhibiting the enzymes involved in the uptake of the neurotransmitters norepinephrine and dopamine from the synaptic cleft, therefore prolonging their duration of action within the neuronal synapse and the downstream effects of these neurotransmitters. More specifically, bupropion binds to the norepinephrine transporter (NET) and the dopamine transporter (DAT). Bupropion was originally classified as an "atypical" antidepressant because it does not exert the same effects as the classical antidepressants such as Monoamine Oxidase Inhibitors (MAOIs), Tricyclic Antidepressants (TCAs), or Selective Serotonin Reuptake Inhibitors (SSRIs). While it has comparable effectiveness to typical first-line options for the treatment of depression such as SSRIs, bupropion is a unique option for the treatment of MDD as it lacks any clinically relevant serotonergic effects, typical of other mood medications, or any effects on histamine or adrenaline receptors. Lack of activity at these receptors results in a more tolerable side effect profile; bupropion is less likely to cause sexual side effects, sedation, or weight gain as compared to SSRIs or TCAs, for example. When used as an aid to smoking cessation, bupropion is thought to confer its anti-craving and anti-withdrawal effects by inhibiting dopamine reuptake, which is thought to be involved in the reward pathways associated with nicotine, and through the antagonism of the nicotinic acetylcholinergic receptor (AChR), thereby blunting the effects of nicotine. Furthermore, the stimulatory effects produced by bupropion in the central nervous system are similar to nicotine's effects, making low doses of bupropion a suitable option as a nicotine substitute. When used in combination with naltrexone in the marketed product ContraveⓇ for chronic weight management, the two components are thought to have effects on areas of the brain involved in the regulation of food intake. This includes the hypothalamus, which is involved in appetite regulation, and the mesolimbic dopamine circuit, which is involved in reward pathways. Studies have shown that the combined activity of bupropion and naltrexone increase the firing rate of hypothalamic pro-opiomelanocortin (POMC) neurons and blockade of opioid receptor-mediated POMC auto-inhibition, which are associated with a reduction in food intake and increased energy expenditure. This combination was also found to reduce food intake when injected directly into the ventral tegmental area of the mesolimbic circuit in mice, which is an area associated with the regulation of reward pathways. •Mechanism of action (Drug B): The mechanism of action of moclobemide involves the selective, reversible inhibition of MAO-A. This inhibition leads to a decrease in the metabolism and destruction of monoamines in the neurotransmitters. This results in an increase in the monoamines, relieving depressive symptoms. •Absorption (Drug A): Bupropion is currently available in 3 distinct, but bioequivalent formulations: immediate release (IR), sustained-release (SR), and extended-release (XL). Immediate Release Formulation In humans, following oral administration of bupropion hydrochloride tablets, peak plasma bupropion concentrations are usually achieved within 2 hours. IR formulations provide a short duration of action and are therefore generally dosed three times per day. Sustained Release Formulation In humans, following oral administration of bupropion hydrochloride sustained-release tablets (SR), peak plasma concentration (Cmax) of bupropion is usually achieved within 3 hours. SR formulations provide a 12-hour extended release of medication and are therefore generally dosed twice per day. Extended Release Formulation Following single oral administration of bupropion hydrochloride extended-release tablets (XL) to healthy volunteers, the median time to peak plasma concentrations for bupropion was approximately 5 hours. The presence of food did not affect the peak concentration or area under the curve of bupropion. XL formulations provide a 24-hour extended release of medication and are therefore generally dosed once per day/ In a trial comparing chronic dosing with bupropion hydrochloride extended-release tablets (SR) 150 mg twice daily to bupropion immediate-release formulation 100 mg 3 times daily, the steady state Cmax for bupropion after bupropion hydrochloride sustained-release tablets (SR) administration was approximately 85% of those achieved after bupropion immediate-release formulation administration. Exposure (AUC) to bupropion was equivalent for both formulations. Bioequivalence was also demonstrated for all three major active metabolites (i.e., hydroxybupropion, threohydrobupropion and erythrohydrobupropion) for both Cmax and AUC. Thus, at steady state, bupropion hydrochloride sustained-release tablets (SR) given twice daily, and the immediate-release formulation of bupropion given 3 times daily, are essentially bioequivalent for both bupropion and the 3 quantitatively important metabolites. Furthermore, in a study comparing 14-day dosing with bupropion hydrochloride extended-release tablets (XL), 300 mg once-daily to the immediate-release formulation of bupropion at 100 mg 3 times daily, equivalence was demonstrated for peak plasma concentration and area under the curve for bupropion and the three metabolites (hydroxybupropion, threohydrobupropion, and erythrohydrobupropion). Additionally, in a study comparing 14-day dosing with bupropion hydrochloride extended-release tablets (XL) 300 mg once daily to the sustained-release formulation of bupropion at 150 mg 2 times daily, equivalence was demonstrated for peak plasma concentration and area under the curve for bupropion and the three metabolites. Bupropion hydrochloride extended-release tablets (SR) can be taken with or without food. Bupropion Cmax and AUC were increased by 11% to 35% and 16% to 19%, respectively, when bupropion hydrochloride extended-release tablets (SR) was administered with food to healthy volunteers in three trials. The food effect is not considered clinically significant. Following a single-dose administration of bupropion hydrochloride extended-release tablets (SR) in humans, Cmax of bupropion's metabolite hydroxybupropion occurs approximately 6 hours post-dose and is approximately 10 times the peak level of the parent drug at steady state. The elimination half-life of hydroxybupropion is approximately 20 (±5) hours and its AUC at steady state is about 17 times that of bupropion. The times to peak concentrations for the erythrohydrobupropion and threohydrobupropion metabolites are similar to that of the hydroxybupropion metabolite. However, their elimination half-lives are longer, 33(±10) and 37 (±13) hours, respectively, and steady-state AUCs are 1.5 and 7 times that of bupropion, respectively. •Absorption (Drug B): Well absorbed from the gastrointestinal tract (> 95%). The presence of food reduces the rate but not the extent of absorption. Hepatic first-pass metabolism reduces bioavailability to about 56% following administration of one dose, but increases to 90% with steady-state dosing as a result of saturation of the first pass effect. Peak plasma concentrations are reached within 0.3 - 1 hours following oral administration with a terminal half-life of 1.6h. •Volume of distribution (Drug A): No volume of distribution available •Volume of distribution (Drug B): 1-1.5 L/Kg •Protein binding (Drug A): In vitro tests show that bupropion is 84% bound to human plasma proteins at concentrations up to 200 mcg per mL. The extent of protein binding of the hydroxybupropion metabolite is similar to that for bupropion, whereas the extent of protein binding of the threohydrobupropion metabolite is about half that seen with bupropion. •Protein binding (Drug B): Approximately 50% (primarily to albumin) •Metabolism (Drug A): Bupropion is extensively metabolized in humans. Three metabolites are active: hydroxybupropion, which is formed via hydroxylation of the tert-butyl group of bupropion, and the amino-alcohol isomers, threohydrobupropion and erythrohydrobupropion, which are formed via reduction of the carbonyl group. In vitro findings suggest that CYP2B6 is the principal isoenzyme involved in the formation of hydroxybupropion, while cytochrome P450 enzymes are not involved in the formation of threohydrobupropion. Hydroxybupropion has been shown to have the same affinity as bupropion for the norepinephrine transporter (NET) but approximately 50% of its antidepressant activity despite reaching concentrations of ~10-fold higher than that of the parent drug. Oxidation of the bupropion side chain results in the formation of a glycine conjugate of meta-chlorobenzoic acid, which is then excreted as the major urinary metabolite. The potency and toxicity of the metabolites relative to bupropion have not been fully characterized. However, it has been demonstrated in an antidepressant screening test in mice that hydroxybupropion is one-half as potent as bupropion, while threohydrobupropion and erythrohydrobupropion are 5-fold less potent than bupropion. This may be of clinical importance because the plasma concentrations of the metabolites are as high as or higher than those of bupropion. Bupropion and its metabolites exhibit linear kinetics following chronic administration of 300 to 450 mg per day. •Metabolism (Drug B): Moclobemide is almost completely metabolized in the liver by Cytochrome P450 2C19 and 2D6. Moclobemide is a substrate of CYP2C19. Although it acts as an inhibitor of CYP1A2, CYP2C19, and CYP2D6. •Route of elimination (Drug A): Bupropion is extensively metabolized in humans. Oxidation of the bupropion side chain results in the formation of a glycine conjugate of metachlorobenzoic acid, which is then excreted as the major urinary metabolite. Following oral administration of 200 mg of 14C-bupropion in humans, 87% and 10% of the radioactive dose were recovered in the urine and feces, respectively. However, the fraction of the oral dose of bupropion excreted unchanged was only 0.5%, a finding consistent with the extensive metabolism of bupropion. •Route of elimination (Drug B): Moclobemide is almost completely renally excreted. •Half-life (Drug A): 24 hours •Half-life (Drug B): 1-2 hours (4 hours in cirrhotic patients); metabolites are renally excreted •Clearance (Drug A): No clearance available •Clearance (Drug B): Clearance of 30-78 L/h, mainly excreted in urine. •Toxicity (Drug A): Symptoms of overdose include seizures, hallucinations, loss of consciousness, tachycardia, and cardiac arrest. •Toxicity (Drug B): LD50 (mouse) is 730mg/kg and LD50 (rat) is 1,300mg/kg. Signs of toxicity include hypertension, drowsiness, dizziness, confusion, tremors, headache, agitation, muscle rigidity and seizures. The effects of moclobemide alone in overdose are negligible, even with high volume ingestion. However, moclobemide overdose with a serotonergic agent (even in small, therapeutic doses) can cause severe serotonin toxicity. The elimination half-life is prolonged by two to four times in overdose, compared with that found in healthy volunteers given therapeutic doses. •Brand Names (Drug A): Aplenzin, Auvelity, Budeprion, Contrave, Forfivo, Wellbutrin, Zyban •Brand Names (Drug B): Manerix •Synonyms (Drug A): No synonyms listed •Synonyms (Drug B): Moclobemid Moclobemida Moclobemide Moclobemidum •Summary (Drug A): Bupropion is a norepinephrine and dopamine reuptake inhibitor used in the treatment of major depressive disorder (MDD), seasonal affective disorder (SAD), and as an aid to smoking cessation. •Summary (Drug B): Moclobemide is a monoamine oxidase inhibitor used in the treatment of major depressive disorder and bipolar disorder.

Bupropion is a dopaminergic agent that is used in the treatment of Parkinson's disease, depression, and smoking cessation. Based on the findings from animal studies, co-administration of bupropion with monoamine oxidase inhibitors may enhance the acute toxicity effects of bupropion, as indicated by an increase in mortality and a decrease in time to death . This interaction applies to both immediate release and sustained release forms of bupropion. The severity of the interaction is major.

Question: Does Bupropion and Moclobemide interact? Information: •Drug A: Bupropion •Drug B: Moclobemide •Severity: MAJOR •Description: The risk or severity of adverse effects can be increased when Moclobemide is combined with Bupropion. •Extended Description: Bupropion is a dopaminergic agent that is used in the treatment of Parkinson's disease, depression, and smoking cessation. Based on the findings from animal studies, co-administration of bupropion with monoamine oxidase inhibitors may enhance the acute toxicity effects of bupropion, as indicated by an increase in mortality and a decrease in time to death . This interaction applies to both immediate release and sustained release forms of bupropion. •Indication (Drug A): Bupropion is indicated for the treatment of major depressive disorder (MDD), seasonal affective disorder (SAD), and as an aid to smoking cessation. When used in combination with naltrexone as the marketed product ContraveⓇ, bupropion is indicated as an adjunct to a reduced-calorie diet and increased physical activity for chronic weight management in adults with an initial body mass index (BMI) of: 30 kg/m^2 or greater (obese) or 27 kg/m^2 or greater (overweight) in the presence of at least one weight-related comorbid condition (e.g., hypertension, type 2 diabetes mellitus, or dyslipidemia). Bupropion is also used off-label as a first-line treatment in patients with ADHD and comorbid bipolar disorder when used as an adjunct to mood stabilizers. •Indication (Drug B): For the treatment of major depressive disorder and bipolar disorder. •Pharmacodynamics (Drug A): Bupropion is chemically unrelated to tricyclic, tetracyclic, selective serotonin re-uptake inhibitors, or other known antidepressant agents. Compared to classical tricyclic antidepressants, Bupropion is a relatively weak inhibitor of the neuronal uptake of norepinephrine and dopamine. In addition, Bupropion does not inhibit monoamine oxidase. Bupropion has been found to be essentially inactive at the serotonin transporter (SERT)(IC50 >10 000 nM), however both bupropion and its primary metabolite hydroxybupropion have been found to block the function of cation-selective serotonin type 3A receptors (5-HT3ARs). Bupropion produces dose-related central nervous system (CNS) stimulant effects in animals, as evidenced by increased locomotor activity, increased rates of responding in various schedule-controlled operant behaviour tasks, and, at high doses, induction of mild stereotyped behaviour. Due to these stimulant effects and selective activity at dopamine and norepinephrine receptors, bupropion has been identified as having an abuse potential. Bupropion has a similar structure to the controlled substance Cathinone, and has been identified as having mild amphetamine-like activity, particularly when inhaled or injected. Bupropion is also known to lower the seizure threshold, making any pre-existing seizure conditions a contraindication to its use. This risk is exacerbated when bupropion is combined with other drugs or substances that lower the seizure threshold, such as cocaine, or in clinical situations that would increase the risk of a seizure such as abrupt alcohol or benzodiazepine withdrawal. As norepinephrine has been shown to have anticonvulsant properties, bupropion's inhibitory effects on NET are thought to contribute to its pro-convulsant activity. Bupropion has been shown to increase blood pressure and pose a risk for exacerbation of unmanaged or pre-existing hypertension, however, clinical trials of bupropion in smokers with CVD have not identified an increased incidence of CV events including stroke or heart attack. In clinical trials, the mean increase in systolic blood pressure associated with the use of bupropion was found to be 1.3 mmHg. •Pharmacodynamics (Drug B): A selective, reversible inhibitor of monoamine oxidase (MAO) which increases the. Besides its presence in sympathetic nerves, there is an abundant evidence that MAO-A is localized in noradrenergic neurons in the locus coeruleus and MAO-B is closely associated with serotonergic neurons of the raphe nucleus. •Mechanism of action (Drug A): Bupropion is a norepinephrine/dopamine-reuptake inhibitor (NDRI) that exerts its pharmacological effects by weakly inhibiting the enzymes involved in the uptake of the neurotransmitters norepinephrine and dopamine from the synaptic cleft, therefore prolonging their duration of action within the neuronal synapse and the downstream effects of these neurotransmitters. More specifically, bupropion binds to the norepinephrine transporter (NET) and the dopamine transporter (DAT). Bupropion was originally classified as an "atypical" antidepressant because it does not exert the same effects as the classical antidepressants such as Monoamine Oxidase Inhibitors (MAOIs), Tricyclic Antidepressants (TCAs), or Selective Serotonin Reuptake Inhibitors (SSRIs). While it has comparable effectiveness to typical first-line options for the treatment of depression such as SSRIs, bupropion is a unique option for the treatment of MDD as it lacks any clinically relevant serotonergic effects, typical of other mood medications, or any effects on histamine or adrenaline receptors. Lack of activity at these receptors results in a more tolerable side effect profile; bupropion is less likely to cause sexual side effects, sedation, or weight gain as compared to SSRIs or TCAs, for example. When used as an aid to smoking cessation, bupropion is thought to confer its anti-craving and anti-withdrawal effects by inhibiting dopamine reuptake, which is thought to be involved in the reward pathways associated with nicotine, and through the antagonism of the nicotinic acetylcholinergic receptor (AChR), thereby blunting the effects of nicotine. Furthermore, the stimulatory effects produced by bupropion in the central nervous system are similar to nicotine's effects, making low doses of bupropion a suitable option as a nicotine substitute. When used in combination with naltrexone in the marketed product ContraveⓇ for chronic weight management, the two components are thought to have effects on areas of the brain involved in the regulation of food intake. This includes the hypothalamus, which is involved in appetite regulation, and the mesolimbic dopamine circuit, which is involved in reward pathways. Studies have shown that the combined activity of bupropion and naltrexone increase the firing rate of hypothalamic pro-opiomelanocortin (POMC) neurons and blockade of opioid receptor-mediated POMC auto-inhibition, which are associated with a reduction in food intake and increased energy expenditure. This combination was also found to reduce food intake when injected directly into the ventral tegmental area of the mesolimbic circuit in mice, which is an area associated with the regulation of reward pathways. •Mechanism of action (Drug B): The mechanism of action of moclobemide involves the selective, reversible inhibition of MAO-A. This inhibition leads to a decrease in the metabolism and destruction of monoamines in the neurotransmitters. This results in an increase in the monoamines, relieving depressive symptoms. •Absorption (Drug A): Bupropion is currently available in 3 distinct, but bioequivalent formulations: immediate release (IR), sustained-release (SR), and extended-release (XL). Immediate Release Formulation In humans, following oral administration of bupropion hydrochloride tablets, peak plasma bupropion concentrations are usually achieved within 2 hours. IR formulations provide a short duration of action and are therefore generally dosed three times per day. Sustained Release Formulation In humans, following oral administration of bupropion hydrochloride sustained-release tablets (SR), peak plasma concentration (Cmax) of bupropion is usually achieved within 3 hours. SR formulations provide a 12-hour extended release of medication and are therefore generally dosed twice per day. Extended Release Formulation Following single oral administration of bupropion hydrochloride extended-release tablets (XL) to healthy volunteers, the median time to peak plasma concentrations for bupropion was approximately 5 hours. The presence of food did not affect the peak concentration or area under the curve of bupropion. XL formulations provide a 24-hour extended release of medication and are therefore generally dosed once per day/ In a trial comparing chronic dosing with bupropion hydrochloride extended-release tablets (SR) 150 mg twice daily to bupropion immediate-release formulation 100 mg 3 times daily, the steady state Cmax for bupropion after bupropion hydrochloride sustained-release tablets (SR) administration was approximately 85% of those achieved after bupropion immediate-release formulation administration. Exposure (AUC) to bupropion was equivalent for both formulations. Bioequivalence was also demonstrated for all three major active metabolites (i.e., hydroxybupropion, threohydrobupropion and erythrohydrobupropion) for both Cmax and AUC. Thus, at steady state, bupropion hydrochloride sustained-release tablets (SR) given twice daily, and the immediate-release formulation of bupropion given 3 times daily, are essentially bioequivalent for both bupropion and the 3 quantitatively important metabolites. Furthermore, in a study comparing 14-day dosing with bupropion hydrochloride extended-release tablets (XL), 300 mg once-daily to the immediate-release formulation of bupropion at 100 mg 3 times daily, equivalence was demonstrated for peak plasma concentration and area under the curve for bupropion and the three metabolites (hydroxybupropion, threohydrobupropion, and erythrohydrobupropion). Additionally, in a study comparing 14-day dosing with bupropion hydrochloride extended-release tablets (XL) 300 mg once daily to the sustained-release formulation of bupropion at 150 mg 2 times daily, equivalence was demonstrated for peak plasma concentration and area under the curve for bupropion and the three metabolites. Bupropion hydrochloride extended-release tablets (SR) can be taken with or without food. Bupropion Cmax and AUC were increased by 11% to 35% and 16% to 19%, respectively, when bupropion hydrochloride extended-release tablets (SR) was administered with food to healthy volunteers in three trials. The food effect is not considered clinically significant. Following a single-dose administration of bupropion hydrochloride extended-release tablets (SR) in humans, Cmax of bupropion's metabolite hydroxybupropion occurs approximately 6 hours post-dose and is approximately 10 times the peak level of the parent drug at steady state. The elimination half-life of hydroxybupropion is approximately 20 (±5) hours and its AUC at steady state is about 17 times that of bupropion. The times to peak concentrations for the erythrohydrobupropion and threohydrobupropion metabolites are similar to that of the hydroxybupropion metabolite. However, their elimination half-lives are longer, 33(±10) and 37 (±13) hours, respectively, and steady-state AUCs are 1.5 and 7 times that of bupropion, respectively. •Absorption (Drug B): Well absorbed from the gastrointestinal tract (> 95%). The presence of food reduces the rate but not the extent of absorption. Hepatic first-pass metabolism reduces bioavailability to about 56% following administration of one dose, but increases to 90% with steady-state dosing as a result of saturation of the first pass effect. Peak plasma concentrations are reached within 0.3 - 1 hours following oral administration with a terminal half-life of 1.6h. •Volume of distribution (Drug A): No volume of distribution available •Volume of distribution (Drug B): 1-1.5 L/Kg •Protein binding (Drug A): In vitro tests show that bupropion is 84% bound to human plasma proteins at concentrations up to 200 mcg per mL. The extent of protein binding of the hydroxybupropion metabolite is similar to that for bupropion, whereas the extent of protein binding of the threohydrobupropion metabolite is about half that seen with bupropion. •Protein binding (Drug B): Approximately 50% (primarily to albumin) •Metabolism (Drug A): Bupropion is extensively metabolized in humans. Three metabolites are active: hydroxybupropion, which is formed via hydroxylation of the tert-butyl group of bupropion, and the amino-alcohol isomers, threohydrobupropion and erythrohydrobupropion, which are formed via reduction of the carbonyl group. In vitro findings suggest that CYP2B6 is the principal isoenzyme involved in the formation of hydroxybupropion, while cytochrome P450 enzymes are not involved in the formation of threohydrobupropion. Hydroxybupropion has been shown to have the same affinity as bupropion for the norepinephrine transporter (NET) but approximately 50% of its antidepressant activity despite reaching concentrations of ~10-fold higher than that of the parent drug. Oxidation of the bupropion side chain results in the formation of a glycine conjugate of meta-chlorobenzoic acid, which is then excreted as the major urinary metabolite. The potency and toxicity of the metabolites relative to bupropion have not been fully characterized. However, it has been demonstrated in an antidepressant screening test in mice that hydroxybupropion is one-half as potent as bupropion, while threohydrobupropion and erythrohydrobupropion are 5-fold less potent than bupropion. This may be of clinical importance because the plasma concentrations of the metabolites are as high as or higher than those of bupropion. Bupropion and its metabolites exhibit linear kinetics following chronic administration of 300 to 450 mg per day. •Metabolism (Drug B): Moclobemide is almost completely metabolized in the liver by Cytochrome P450 2C19 and 2D6. Moclobemide is a substrate of CYP2C19. Although it acts as an inhibitor of CYP1A2, CYP2C19, and CYP2D6. •Route of elimination (Drug A): Bupropion is extensively metabolized in humans. Oxidation of the bupropion side chain results in the formation of a glycine conjugate of metachlorobenzoic acid, which is then excreted as the major urinary metabolite. Following oral administration of 200 mg of 14C-bupropion in humans, 87% and 10% of the radioactive dose were recovered in the urine and feces, respectively. However, the fraction of the oral dose of bupropion excreted unchanged was only 0.5%, a finding consistent with the extensive metabolism of bupropion. •Route of elimination (Drug B): Moclobemide is almost completely renally excreted. •Half-life (Drug A): 24 hours •Half-life (Drug B): 1-2 hours (4 hours in cirrhotic patients); metabolites are renally excreted •Clearance (Drug A): No clearance available •Clearance (Drug B): Clearance of 30-78 L/h, mainly excreted in urine. •Toxicity (Drug A): Symptoms of overdose include seizures, hallucinations, loss of consciousness, tachycardia, and cardiac arrest. •Toxicity (Drug B): LD50 (mouse) is 730mg/kg and LD50 (rat) is 1,300mg/kg. Signs of toxicity include hypertension, drowsiness, dizziness, confusion, tremors, headache, agitation, muscle rigidity and seizures. The effects of moclobemide alone in overdose are negligible, even with high volume ingestion. However, moclobemide overdose with a serotonergic agent (even in small, therapeutic doses) can cause severe serotonin toxicity. The elimination half-life is prolonged by two to four times in overdose, compared with that found in healthy volunteers given therapeutic doses. •Brand Names (Drug A): Aplenzin, Auvelity, Budeprion, Contrave, Forfivo, Wellbutrin, Zyban •Brand Names (Drug B): Manerix •Synonyms (Drug A): No synonyms listed •Synonyms (Drug B): Moclobemid Moclobemida Moclobemide Moclobemidum •Summary (Drug A): Bupropion is a norepinephrine and dopamine reuptake inhibitor used in the treatment of major depressive disorder (MDD), seasonal affective disorder (SAD), and as an aid to smoking cessation. •Summary (Drug B): Moclobemide is a monoamine oxidase inhibitor used in the treatment of major depressive disorder and bipolar disorder. Output: Bupropion is a dopaminergic agent that is used in the treatment of Parkinson's disease, depression, and smoking cessation. Based on the findings from animal studies, co-administration of bupropion with monoamine oxidase inhibitors may enhance the acute toxicity effects of bupropion, as indicated by an increase in mortality and a decrease in time to death . This interaction applies to both immediate release and sustained release forms of bupropion. The severity of the interaction is major.

Does Bupropion and Modafinil interact?

•Drug A: Bupropion •Drug B: Modafinil •Severity: MODERATE •Description: The metabolism of Bupropion can be decreased when combined with Modafinil. •Extended Description: The subject drug is known to be an inhibitor of CYP2C9 while the affected drug is reported to be metabolized by CYP2C9. Concomitant administration of these agents can cause an increase in the serum concentration of the affected drug due to decreased metabolism by CYP2C9, which may result in increased incidence and/or severity of adverse effects related to the affected drug. •Indication (Drug A): Bupropion is indicated for the treatment of major depressive disorder (MDD), seasonal affective disorder (SAD), and as an aid to smoking cessation. When used in combination with naltrexone as the marketed product ContraveⓇ, bupropion is indicated as an adjunct to a reduced-calorie diet and increased physical activity for chronic weight management in adults with an initial body mass index (BMI) of: 30 kg/m^2 or greater (obese) or 27 kg/m^2 or greater (overweight) in the presence of at least one weight-related comorbid condition (e.g., hypertension, type 2 diabetes mellitus, or dyslipidemia). Bupropion is also used off-label as a first-line treatment in patients with ADHD and comorbid bipolar disorder when used as an adjunct to mood stabilizers. •Indication (Drug B): To improve wakefulness in patients with excessive daytime sleepiness (EDS) associated with narcolepsy. •Pharmacodynamics (Drug A): Bupropion is chemically unrelated to tricyclic, tetracyclic, selective serotonin re-uptake inhibitors, or other known antidepressant agents. Compared to classical tricyclic antidepressants, Bupropion is a relatively weak inhibitor of the neuronal uptake of norepinephrine and dopamine. In addition, Bupropion does not inhibit monoamine oxidase. Bupropion has been found to be essentially inactive at the serotonin transporter (SERT)(IC50 >10 000 nM), however both bupropion and its primary metabolite hydroxybupropion have been found to block the function of cation-selective serotonin type 3A receptors (5-HT3ARs). Bupropion produces dose-related central nervous system (CNS) stimulant effects in animals, as evidenced by increased locomotor activity, increased rates of responding in various schedule-controlled operant behaviour tasks, and, at high doses, induction of mild stereotyped behaviour. Due to these stimulant effects and selective activity at dopamine and norepinephrine receptors, bupropion has been identified as having an abuse potential. Bupropion has a similar structure to the controlled substance Cathinone, and has been identified as having mild amphetamine-like activity, particularly when inhaled or injected. Bupropion is also known to lower the seizure threshold, making any pre-existing seizure conditions a contraindication to its use. This risk is exacerbated when bupropion is combined with other drugs or substances that lower the seizure threshold, such as cocaine, or in clinical situations that would increase the risk of a seizure such as abrupt alcohol or benzodiazepine withdrawal. As norepinephrine has been shown to have anticonvulsant properties, bupropion's inhibitory effects on NET are thought to contribute to its pro-convulsant activity. Bupropion has been shown to increase blood pressure and pose a risk for exacerbation of unmanaged or pre-existing hypertension, however, clinical trials of bupropion in smokers with CVD have not identified an increased incidence of CV events including stroke or heart attack. In clinical trials, the mean increase in systolic blood pressure associated with the use of bupropion was found to be 1.3 mmHg. •Pharmacodynamics (Drug B): Modafinil is a stimulant drug marketed as a 'wakefulness promoting agent' and is one of the stimulants used in the treatment of narcolepsy. Narcolepsy is caused by dysfunction of a family of wakefulness-promoting and sleep-suppressing peptides, the orexins, whose neurons are activated by modafinil. The prexin neuron activation is associated with psychoactivation and euphoria. Modafinil is not indicated for complaints of lack of energy or fatigue; but it appears to be very helpful for some patients. Also, it has been used in the treatment of hypersomnia, a disorder in which patients lack the capacity for meaningful sleep and may require ten or more hours per day. Recent studies have have found that modafinil may help recovering cocaine addicts fight their addiction. •Mechanism of action (Drug A): Bupropion is a norepinephrine/dopamine-reuptake inhibitor (NDRI) that exerts its pharmacological effects by weakly inhibiting the enzymes involved in the uptake of the neurotransmitters norepinephrine and dopamine from the synaptic cleft, therefore prolonging their duration of action within the neuronal synapse and the downstream effects of these neurotransmitters. More specifically, bupropion binds to the norepinephrine transporter (NET) and the dopamine transporter (DAT). Bupropion was originally classified as an "atypical" antidepressant because it does not exert the same effects as the classical antidepressants such as Monoamine Oxidase Inhibitors (MAOIs), Tricyclic Antidepressants (TCAs), or Selective Serotonin Reuptake Inhibitors (SSRIs). While it has comparable effectiveness to typical first-line options for the treatment of depression such as SSRIs, bupropion is a unique option for the treatment of MDD as it lacks any clinically relevant serotonergic effects, typical of other mood medications, or any effects on histamine or adrenaline receptors. Lack of activity at these receptors results in a more tolerable side effect profile; bupropion is less likely to cause sexual side effects, sedation, or weight gain as compared to SSRIs or TCAs, for example. When used as an aid to smoking cessation, bupropion is thought to confer its anti-craving and anti-withdrawal effects by inhibiting dopamine reuptake, which is thought to be involved in the reward pathways associated with nicotine, and through the antagonism of the nicotinic acetylcholinergic receptor (AChR), thereby blunting the effects of nicotine. Furthermore, the stimulatory effects produced by bupropion in the central nervous system are similar to nicotine's effects, making low doses of bupropion a suitable option as a nicotine substitute. When used in combination with naltrexone in the marketed product ContraveⓇ for chronic weight management, the two components are thought to have effects on areas of the brain involved in the regulation of food intake. This includes the hypothalamus, which is involved in appetite regulation, and the mesolimbic dopamine circuit, which is involved in reward pathways. Studies have shown that the combined activity of bupropion and naltrexone increase the firing rate of hypothalamic pro-opiomelanocortin (POMC) neurons and blockade of opioid receptor-mediated POMC auto-inhibition, which are associated with a reduction in food intake and increased energy expenditure. This combination was also found to reduce food intake when injected directly into the ventral tegmental area of the mesolimbic circuit in mice, which is an area associated with the regulation of reward pathways. •Mechanism of action (Drug B): The exact mechanism of action is unclear, although in vitro studies have shown it to inhibit the reuptake of dopamine by binding to the dopamine reuptake pump, and lead to an increase in extracellular dopamine. Modafinil activates glutamatergic circuits while inhibiting GABA. Modafinil is thought to have less potential for abuse than other stimulants due to the absence of any significant euphoric or pleasurable effects. It is possible that modafinil acts by a synergistic combination of mechanisms including direct inhibition of dopamine reuptake, indirect inhibition of noradrenalin reuptake in the VLPO and orexin activation. Modafinil has partial alpha 1B-adrenergic agonist effects by directly stimulating the receptors. •Absorption (Drug A): Bupropion is currently available in 3 distinct, but bioequivalent formulations: immediate release (IR), sustained-release (SR), and extended-release (XL). Immediate Release Formulation In humans, following oral administration of bupropion hydrochloride tablets, peak plasma bupropion concentrations are usually achieved within 2 hours. IR formulations provide a short duration of action and are therefore generally dosed three times per day. Sustained Release Formulation In humans, following oral administration of bupropion hydrochloride sustained-release tablets (SR), peak plasma concentration (Cmax) of bupropion is usually achieved within 3 hours. SR formulations provide a 12-hour extended release of medication and are therefore generally dosed twice per day. Extended Release Formulation Following single oral administration of bupropion hydrochloride extended-release tablets (XL) to healthy volunteers, the median time to peak plasma concentrations for bupropion was approximately 5 hours. The presence of food did not affect the peak concentration or area under the curve of bupropion. XL formulations provide a 24-hour extended release of medication and are therefore generally dosed once per day/ In a trial comparing chronic dosing with bupropion hydrochloride extended-release tablets (SR) 150 mg twice daily to bupropion immediate-release formulation 100 mg 3 times daily, the steady state Cmax for bupropion after bupropion hydrochloride sustained-release tablets (SR) administration was approximately 85% of those achieved after bupropion immediate-release formulation administration. Exposure (AUC) to bupropion was equivalent for both formulations. Bioequivalence was also demonstrated for all three major active metabolites (i.e., hydroxybupropion, threohydrobupropion and erythrohydrobupropion) for both Cmax and AUC. Thus, at steady state, bupropion hydrochloride sustained-release tablets (SR) given twice daily, and the immediate-release formulation of bupropion given 3 times daily, are essentially bioequivalent for both bupropion and the 3 quantitatively important metabolites. Furthermore, in a study comparing 14-day dosing with bupropion hydrochloride extended-release tablets (XL), 300 mg once-daily to the immediate-release formulation of bupropion at 100 mg 3 times daily, equivalence was demonstrated for peak plasma concentration and area under the curve for bupropion and the three metabolites (hydroxybupropion, threohydrobupropion, and erythrohydrobupropion). Additionally, in a study comparing 14-day dosing with bupropion hydrochloride extended-release tablets (XL) 300 mg once daily to the sustained-release formulation of bupropion at 150 mg 2 times daily, equivalence was demonstrated for peak plasma concentration and area under the curve for bupropion and the three metabolites. Bupropion hydrochloride extended-release tablets (SR) can be taken with or without food. Bupropion Cmax and AUC were increased by 11% to 35% and 16% to 19%, respectively, when bupropion hydrochloride extended-release tablets (SR) was administered with food to healthy volunteers in three trials. The food effect is not considered clinically significant. Following a single-dose administration of bupropion hydrochloride extended-release tablets (SR) in humans, Cmax of bupropion's metabolite hydroxybupropion occurs approximately 6 hours post-dose and is approximately 10 times the peak level of the parent drug at steady state. The elimination half-life of hydroxybupropion is approximately 20 (±5) hours and its AUC at steady state is about 17 times that of bupropion. The times to peak concentrations for the erythrohydrobupropion and threohydrobupropion metabolites are similar to that of the hydroxybupropion metabolite. However, their elimination half-lives are longer, 33(±10) and 37 (±13) hours, respectively, and steady-state AUCs are 1.5 and 7 times that of bupropion, respectively. •Absorption (Drug B): Rapid following oral administration. •Volume of distribution (Drug A): No volume of distribution available •Volume of distribution (Drug B): 0.9 L/kg •Protein binding (Drug A): In vitro tests show that bupropion is 84% bound to human plasma proteins at concentrations up to 200 mcg per mL. The extent of protein binding of the hydroxybupropion metabolite is similar to that for bupropion, whereas the extent of protein binding of the threohydrobupropion metabolite is about half that seen with bupropion. •Protein binding (Drug B): 60% •Metabolism (Drug A): Bupropion is extensively metabolized in humans. Three metabolites are active: hydroxybupropion, which is formed via hydroxylation of the tert-butyl group of bupropion, and the amino-alcohol isomers, threohydrobupropion and erythrohydrobupropion, which are formed via reduction of the carbonyl group. In vitro findings suggest that CYP2B6 is the principal isoenzyme involved in the formation of hydroxybupropion, while cytochrome P450 enzymes are not involved in the formation of threohydrobupropion. Hydroxybupropion has been shown to have the same affinity as bupropion for the norepinephrine transporter (NET) but approximately 50% of its antidepressant activity despite reaching concentrations of ~10-fold higher than that of the parent drug. Oxidation of the bupropion side chain results in the formation of a glycine conjugate of meta-chlorobenzoic acid, which is then excreted as the major urinary metabolite. The potency and toxicity of the metabolites relative to bupropion have not been fully characterized. However, it has been demonstrated in an antidepressant screening test in mice that hydroxybupropion is one-half as potent as bupropion, while threohydrobupropion and erythrohydrobupropion are 5-fold less potent than bupropion. This may be of clinical importance because the plasma concentrations of the metabolites are as high as or higher than those of bupropion. Bupropion and its metabolites exhibit linear kinetics following chronic administration of 300 to 450 mg per day. •Metabolism (Drug B): Hepatic •Route of elimination (Drug A): Bupropion is extensively metabolized in humans. Oxidation of the bupropion side chain results in the formation of a glycine conjugate of metachlorobenzoic acid, which is then excreted as the major urinary metabolite. Following oral administration of 200 mg of 14C-bupropion in humans, 87% and 10% of the radioactive dose were recovered in the urine and feces, respectively. However, the fraction of the oral dose of bupropion excreted unchanged was only 0.5%, a finding consistent with the extensive metabolism of bupropion. •Route of elimination (Drug B): The major route of elimination is metabolism (~90%), primarily by the liver, with subsequent renal elimination of the metabolites. •Half-life (Drug A): 24 hours •Half-life (Drug B): 23-215 hours •Clearance (Drug A): No clearance available •Clearance (Drug B): No clearance available •Toxicity (Drug A): Symptoms of overdose include seizures, hallucinations, loss of consciousness, tachycardia, and cardiac arrest. •Toxicity (Drug B): No toxicity available •Brand Names (Drug A): Aplenzin, Auvelity, Budeprion, Contrave, Forfivo, Wellbutrin, Zyban •Brand Names (Drug B): Provigil •Synonyms (Drug A): No synonyms listed •Synonyms (Drug B): Modafinil Modafinilo Modafinilum •Summary (Drug A): Bupropion is a norepinephrine and dopamine reuptake inhibitor used in the treatment of major depressive disorder (MDD), seasonal affective disorder (SAD), and as an aid to smoking cessation. •Summary (Drug B): Modafinil is a stimulant used to improve wakefulness in patients with sleep apnea, narcolepsy, or shift work disorder.

The subject drug is known to be an inhibitor of CYP2C9 while the affected drug is reported to be metabolized by CYP2C9. Concomitant administration of these agents can cause an increase in the serum concentration of the affected drug due to decreased metabolism by CYP2C9, which may result in increased incidence and/or severity of adverse effects related to the affected drug. The severity of the interaction is moderate.

Question: Does Bupropion and Modafinil interact? Information: •Drug A: Bupropion •Drug B: Modafinil •Severity: MODERATE •Description: The metabolism of Bupropion can be decreased when combined with Modafinil. •Extended Description: The subject drug is known to be an inhibitor of CYP2C9 while the affected drug is reported to be metabolized by CYP2C9. Concomitant administration of these agents can cause an increase in the serum concentration of the affected drug due to decreased metabolism by CYP2C9, which may result in increased incidence and/or severity of adverse effects related to the affected drug. •Indication (Drug A): Bupropion is indicated for the treatment of major depressive disorder (MDD), seasonal affective disorder (SAD), and as an aid to smoking cessation. When used in combination with naltrexone as the marketed product ContraveⓇ, bupropion is indicated as an adjunct to a reduced-calorie diet and increased physical activity for chronic weight management in adults with an initial body mass index (BMI) of: 30 kg/m^2 or greater (obese) or 27 kg/m^2 or greater (overweight) in the presence of at least one weight-related comorbid condition (e.g., hypertension, type 2 diabetes mellitus, or dyslipidemia). Bupropion is also used off-label as a first-line treatment in patients with ADHD and comorbid bipolar disorder when used as an adjunct to mood stabilizers. •Indication (Drug B): To improve wakefulness in patients with excessive daytime sleepiness (EDS) associated with narcolepsy. •Pharmacodynamics (Drug A): Bupropion is chemically unrelated to tricyclic, tetracyclic, selective serotonin re-uptake inhibitors, or other known antidepressant agents. Compared to classical tricyclic antidepressants, Bupropion is a relatively weak inhibitor of the neuronal uptake of norepinephrine and dopamine. In addition, Bupropion does not inhibit monoamine oxidase. Bupropion has been found to be essentially inactive at the serotonin transporter (SERT)(IC50 >10 000 nM), however both bupropion and its primary metabolite hydroxybupropion have been found to block the function of cation-selective serotonin type 3A receptors (5-HT3ARs). Bupropion produces dose-related central nervous system (CNS) stimulant effects in animals, as evidenced by increased locomotor activity, increased rates of responding in various schedule-controlled operant behaviour tasks, and, at high doses, induction of mild stereotyped behaviour. Due to these stimulant effects and selective activity at dopamine and norepinephrine receptors, bupropion has been identified as having an abuse potential. Bupropion has a similar structure to the controlled substance Cathinone, and has been identified as having mild amphetamine-like activity, particularly when inhaled or injected. Bupropion is also known to lower the seizure threshold, making any pre-existing seizure conditions a contraindication to its use. This risk is exacerbated when bupropion is combined with other drugs or substances that lower the seizure threshold, such as cocaine, or in clinical situations that would increase the risk of a seizure such as abrupt alcohol or benzodiazepine withdrawal. As norepinephrine has been shown to have anticonvulsant properties, bupropion's inhibitory effects on NET are thought to contribute to its pro-convulsant activity. Bupropion has been shown to increase blood pressure and pose a risk for exacerbation of unmanaged or pre-existing hypertension, however, clinical trials of bupropion in smokers with CVD have not identified an increased incidence of CV events including stroke or heart attack. In clinical trials, the mean increase in systolic blood pressure associated with the use of bupropion was found to be 1.3 mmHg. •Pharmacodynamics (Drug B): Modafinil is a stimulant drug marketed as a 'wakefulness promoting agent' and is one of the stimulants used in the treatment of narcolepsy. Narcolepsy is caused by dysfunction of a family of wakefulness-promoting and sleep-suppressing peptides, the orexins, whose neurons are activated by modafinil. The prexin neuron activation is associated with psychoactivation and euphoria. Modafinil is not indicated for complaints of lack of energy or fatigue; but it appears to be very helpful for some patients. Also, it has been used in the treatment of hypersomnia, a disorder in which patients lack the capacity for meaningful sleep and may require ten or more hours per day. Recent studies have have found that modafinil may help recovering cocaine addicts fight their addiction. •Mechanism of action (Drug A): Bupropion is a norepinephrine/dopamine-reuptake inhibitor (NDRI) that exerts its pharmacological effects by weakly inhibiting the enzymes involved in the uptake of the neurotransmitters norepinephrine and dopamine from the synaptic cleft, therefore prolonging their duration of action within the neuronal synapse and the downstream effects of these neurotransmitters. More specifically, bupropion binds to the norepinephrine transporter (NET) and the dopamine transporter (DAT). Bupropion was originally classified as an "atypical" antidepressant because it does not exert the same effects as the classical antidepressants such as Monoamine Oxidase Inhibitors (MAOIs), Tricyclic Antidepressants (TCAs), or Selective Serotonin Reuptake Inhibitors (SSRIs). While it has comparable effectiveness to typical first-line options for the treatment of depression such as SSRIs, bupropion is a unique option for the treatment of MDD as it lacks any clinically relevant serotonergic effects, typical of other mood medications, or any effects on histamine or adrenaline receptors. Lack of activity at these receptors results in a more tolerable side effect profile; bupropion is less likely to cause sexual side effects, sedation, or weight gain as compared to SSRIs or TCAs, for example. When used as an aid to smoking cessation, bupropion is thought to confer its anti-craving and anti-withdrawal effects by inhibiting dopamine reuptake, which is thought to be involved in the reward pathways associated with nicotine, and through the antagonism of the nicotinic acetylcholinergic receptor (AChR), thereby blunting the effects of nicotine. Furthermore, the stimulatory effects produced by bupropion in the central nervous system are similar to nicotine's effects, making low doses of bupropion a suitable option as a nicotine substitute. When used in combination with naltrexone in the marketed product ContraveⓇ for chronic weight management, the two components are thought to have effects on areas of the brain involved in the regulation of food intake. This includes the hypothalamus, which is involved in appetite regulation, and the mesolimbic dopamine circuit, which is involved in reward pathways. Studies have shown that the combined activity of bupropion and naltrexone increase the firing rate of hypothalamic pro-opiomelanocortin (POMC) neurons and blockade of opioid receptor-mediated POMC auto-inhibition, which are associated with a reduction in food intake and increased energy expenditure. This combination was also found to reduce food intake when injected directly into the ventral tegmental area of the mesolimbic circuit in mice, which is an area associated with the regulation of reward pathways. •Mechanism of action (Drug B): The exact mechanism of action is unclear, although in vitro studies have shown it to inhibit the reuptake of dopamine by binding to the dopamine reuptake pump, and lead to an increase in extracellular dopamine. Modafinil activates glutamatergic circuits while inhibiting GABA. Modafinil is thought to have less potential for abuse than other stimulants due to the absence of any significant euphoric or pleasurable effects. It is possible that modafinil acts by a synergistic combination of mechanisms including direct inhibition of dopamine reuptake, indirect inhibition of noradrenalin reuptake in the VLPO and orexin activation. Modafinil has partial alpha 1B-adrenergic agonist effects by directly stimulating the receptors. •Absorption (Drug A): Bupropion is currently available in 3 distinct, but bioequivalent formulations: immediate release (IR), sustained-release (SR), and extended-release (XL). Immediate Release Formulation In humans, following oral administration of bupropion hydrochloride tablets, peak plasma bupropion concentrations are usually achieved within 2 hours. IR formulations provide a short duration of action and are therefore generally dosed three times per day. Sustained Release Formulation In humans, following oral administration of bupropion hydrochloride sustained-release tablets (SR), peak plasma concentration (Cmax) of bupropion is usually achieved within 3 hours. SR formulations provide a 12-hour extended release of medication and are therefore generally dosed twice per day. Extended Release Formulation Following single oral administration of bupropion hydrochloride extended-release tablets (XL) to healthy volunteers, the median time to peak plasma concentrations for bupropion was approximately 5 hours. The presence of food did not affect the peak concentration or area under the curve of bupropion. XL formulations provide a 24-hour extended release of medication and are therefore generally dosed once per day/ In a trial comparing chronic dosing with bupropion hydrochloride extended-release tablets (SR) 150 mg twice daily to bupropion immediate-release formulation 100 mg 3 times daily, the steady state Cmax for bupropion after bupropion hydrochloride sustained-release tablets (SR) administration was approximately 85% of those achieved after bupropion immediate-release formulation administration. Exposure (AUC) to bupropion was equivalent for both formulations. Bioequivalence was also demonstrated for all three major active metabolites (i.e., hydroxybupropion, threohydrobupropion and erythrohydrobupropion) for both Cmax and AUC. Thus, at steady state, bupropion hydrochloride sustained-release tablets (SR) given twice daily, and the immediate-release formulation of bupropion given 3 times daily, are essentially bioequivalent for both bupropion and the 3 quantitatively important metabolites. Furthermore, in a study comparing 14-day dosing with bupropion hydrochloride extended-release tablets (XL), 300 mg once-daily to the immediate-release formulation of bupropion at 100 mg 3 times daily, equivalence was demonstrated for peak plasma concentration and area under the curve for bupropion and the three metabolites (hydroxybupropion, threohydrobupropion, and erythrohydrobupropion). Additionally, in a study comparing 14-day dosing with bupropion hydrochloride extended-release tablets (XL) 300 mg once daily to the sustained-release formulation of bupropion at 150 mg 2 times daily, equivalence was demonstrated for peak plasma concentration and area under the curve for bupropion and the three metabolites. Bupropion hydrochloride extended-release tablets (SR) can be taken with or without food. Bupropion Cmax and AUC were increased by 11% to 35% and 16% to 19%, respectively, when bupropion hydrochloride extended-release tablets (SR) was administered with food to healthy volunteers in three trials. The food effect is not considered clinically significant. Following a single-dose administration of bupropion hydrochloride extended-release tablets (SR) in humans, Cmax of bupropion's metabolite hydroxybupropion occurs approximately 6 hours post-dose and is approximately 10 times the peak level of the parent drug at steady state. The elimination half-life of hydroxybupropion is approximately 20 (±5) hours and its AUC at steady state is about 17 times that of bupropion. The times to peak concentrations for the erythrohydrobupropion and threohydrobupropion metabolites are similar to that of the hydroxybupropion metabolite. However, their elimination half-lives are longer, 33(±10) and 37 (±13) hours, respectively, and steady-state AUCs are 1.5 and 7 times that of bupropion, respectively. •Absorption (Drug B): Rapid following oral administration. •Volume of distribution (Drug A): No volume of distribution available •Volume of distribution (Drug B): 0.9 L/kg •Protein binding (Drug A): In vitro tests show that bupropion is 84% bound to human plasma proteins at concentrations up to 200 mcg per mL. The extent of protein binding of the hydroxybupropion metabolite is similar to that for bupropion, whereas the extent of protein binding of the threohydrobupropion metabolite is about half that seen with bupropion. •Protein binding (Drug B): 60% •Metabolism (Drug A): Bupropion is extensively metabolized in humans. Three metabolites are active: hydroxybupropion, which is formed via hydroxylation of the tert-butyl group of bupropion, and the amino-alcohol isomers, threohydrobupropion and erythrohydrobupropion, which are formed via reduction of the carbonyl group. In vitro findings suggest that CYP2B6 is the principal isoenzyme involved in the formation of hydroxybupropion, while cytochrome P450 enzymes are not involved in the formation of threohydrobupropion. Hydroxybupropion has been shown to have the same affinity as bupropion for the norepinephrine transporter (NET) but approximately 50% of its antidepressant activity despite reaching concentrations of ~10-fold higher than that of the parent drug. Oxidation of the bupropion side chain results in the formation of a glycine conjugate of meta-chlorobenzoic acid, which is then excreted as the major urinary metabolite. The potency and toxicity of the metabolites relative to bupropion have not been fully characterized. However, it has been demonstrated in an antidepressant screening test in mice that hydroxybupropion is one-half as potent as bupropion, while threohydrobupropion and erythrohydrobupropion are 5-fold less potent than bupropion. This may be of clinical importance because the plasma concentrations of the metabolites are as high as or higher than those of bupropion. Bupropion and its metabolites exhibit linear kinetics following chronic administration of 300 to 450 mg per day. •Metabolism (Drug B): Hepatic •Route of elimination (Drug A): Bupropion is extensively metabolized in humans. Oxidation of the bupropion side chain results in the formation of a glycine conjugate of metachlorobenzoic acid, which is then excreted as the major urinary metabolite. Following oral administration of 200 mg of 14C-bupropion in humans, 87% and 10% of the radioactive dose were recovered in the urine and feces, respectively. However, the fraction of the oral dose of bupropion excreted unchanged was only 0.5%, a finding consistent with the extensive metabolism of bupropion. •Route of elimination (Drug B): The major route of elimination is metabolism (~90%), primarily by the liver, with subsequent renal elimination of the metabolites. •Half-life (Drug A): 24 hours •Half-life (Drug B): 23-215 hours •Clearance (Drug A): No clearance available •Clearance (Drug B): No clearance available •Toxicity (Drug A): Symptoms of overdose include seizures, hallucinations, loss of consciousness, tachycardia, and cardiac arrest. •Toxicity (Drug B): No toxicity available •Brand Names (Drug A): Aplenzin, Auvelity, Budeprion, Contrave, Forfivo, Wellbutrin, Zyban •Brand Names (Drug B): Provigil •Synonyms (Drug A): No synonyms listed •Synonyms (Drug B): Modafinil Modafinilo Modafinilum •Summary (Drug A): Bupropion is a norepinephrine and dopamine reuptake inhibitor used in the treatment of major depressive disorder (MDD), seasonal affective disorder (SAD), and as an aid to smoking cessation. •Summary (Drug B): Modafinil is a stimulant used to improve wakefulness in patients with sleep apnea, narcolepsy, or shift work disorder. Output: The subject drug is known to be an inhibitor of CYP2C9 while the affected drug is reported to be metabolized by CYP2C9. Concomitant administration of these agents can cause an increase in the serum concentration of the affected drug due to decreased metabolism by CYP2C9, which may result in increased incidence and/or severity of adverse effects related to the affected drug. The severity of the interaction is moderate.

Does Bupropion and Molindone interact?

•Drug A: Bupropion •Drug B: Molindone •Severity: MODERATE •Description: The risk or severity of CNS depression can be increased when Bupropion is combined with Molindone. •Extended Description: Central nervous system (CNS) depressants can cause sedation, falls, respiratory depression, coma, and death.2,3 The potential interaction between a CNS depressant and another CNS depressant drug due to synergistic effects is well documented in the literature, although the risk and severity of CNS depression vary from each drug. The subject and affected drugs are both CNS depressants that, when co-administered, may result in a more profound CNS depression. As the risk and severity of CNS depression resulting from the combined use of CNS depressants vary from each agent, each interaction between CNS depressants should be considered individually. •Indication (Drug A): Bupropion is indicated for the treatment of major depressive disorder (MDD), seasonal affective disorder (SAD), and as an aid to smoking cessation. When used in combination with naltrexone as the marketed product ContraveⓇ, bupropion is indicated as an adjunct to a reduced-calorie diet and increased physical activity for chronic weight management in adults with an initial body mass index (BMI) of: 30 kg/m^2 or greater (obese) or 27 kg/m^2 or greater (overweight) in the presence of at least one weight-related comorbid condition (e.g., hypertension, type 2 diabetes mellitus, or dyslipidemia). Bupropion is also used off-label as a first-line treatment in patients with ADHD and comorbid bipolar disorder when used as an adjunct to mood stabilizers. •Indication (Drug B): Molindone is used for the management of the manifestations of psychotic disorders. •Pharmacodynamics (Drug A): Bupropion is chemically unrelated to tricyclic, tetracyclic, selective serotonin re-uptake inhibitors, or other known antidepressant agents. Compared to classical tricyclic antidepressants, Bupropion is a relatively weak inhibitor of the neuronal uptake of norepinephrine and dopamine. In addition, Bupropion does not inhibit monoamine oxidase. Bupropion has been found to be essentially inactive at the serotonin transporter (SERT)(IC50 >10 000 nM), however both bupropion and its primary metabolite hydroxybupropion have been found to block the function of cation-selective serotonin type 3A receptors (5-HT3ARs). Bupropion produces dose-related central nervous system (CNS) stimulant effects in animals, as evidenced by increased locomotor activity, increased rates of responding in various schedule-controlled operant behaviour tasks, and, at high doses, induction of mild stereotyped behaviour. Due to these stimulant effects and selective activity at dopamine and norepinephrine receptors, bupropion has been identified as having an abuse potential. Bupropion has a similar structure to the controlled substance Cathinone, and has been identified as having mild amphetamine-like activity, particularly when inhaled or injected. Bupropion is also known to lower the seizure threshold, making any pre-existing seizure conditions a contraindication to its use. This risk is exacerbated when bupropion is combined with other drugs or substances that lower the seizure threshold, such as cocaine, or in clinical situations that would increase the risk of a seizure such as abrupt alcohol or benzodiazepine withdrawal. As norepinephrine has been shown to have anticonvulsant properties, bupropion's inhibitory effects on NET are thought to contribute to its pro-convulsant activity. Bupropion has been shown to increase blood pressure and pose a risk for exacerbation of unmanaged or pre-existing hypertension, however, clinical trials of bupropion in smokers with CVD have not identified an increased incidence of CV events including stroke or heart attack. In clinical trials, the mean increase in systolic blood pressure associated with the use of bupropion was found to be 1.3 mmHg. •Pharmacodynamics (Drug B): Molindone is a dihydroindolone compound which is not structurally related to the phenothiazines, the butyrophenones, or the thioxanthenes. Molindone has a pharmacological profile in laboratory animals which predominantly resembles that of major tranquilizers causing reduction of spontaneous locomotion and aggressiveness, suppression of a conditioned response and antagonism of the bizarre stereotyped behavior and hyperactivity induced by amphetamines. In addition, molindone antagonizes the depression caused by the tranquilizing agent tetrabenazine. •Mechanism of action (Drug A): Bupropion is a norepinephrine/dopamine-reuptake inhibitor (NDRI) that exerts its pharmacological effects by weakly inhibiting the enzymes involved in the uptake of the neurotransmitters norepinephrine and dopamine from the synaptic cleft, therefore prolonging their duration of action within the neuronal synapse and the downstream effects of these neurotransmitters. More specifically, bupropion binds to the norepinephrine transporter (NET) and the dopamine transporter (DAT). Bupropion was originally classified as an "atypical" antidepressant because it does not exert the same effects as the classical antidepressants such as Monoamine Oxidase Inhibitors (MAOIs), Tricyclic Antidepressants (TCAs), or Selective Serotonin Reuptake Inhibitors (SSRIs). While it has comparable effectiveness to typical first-line options for the treatment of depression such as SSRIs, bupropion is a unique option for the treatment of MDD as it lacks any clinically relevant serotonergic effects, typical of other mood medications, or any effects on histamine or adrenaline receptors. Lack of activity at these receptors results in a more tolerable side effect profile; bupropion is less likely to cause sexual side effects, sedation, or weight gain as compared to SSRIs or TCAs, for example. When used as an aid to smoking cessation, bupropion is thought to confer its anti-craving and anti-withdrawal effects by inhibiting dopamine reuptake, which is thought to be involved in the reward pathways associated with nicotine, and through the antagonism of the nicotinic acetylcholinergic receptor (AChR), thereby blunting the effects of nicotine. Furthermore, the stimulatory effects produced by bupropion in the central nervous system are similar to nicotine's effects, making low doses of bupropion a suitable option as a nicotine substitute. When used in combination with naltrexone in the marketed product ContraveⓇ for chronic weight management, the two components are thought to have effects on areas of the brain involved in the regulation of food intake. This includes the hypothalamus, which is involved in appetite regulation, and the mesolimbic dopamine circuit, which is involved in reward pathways. Studies have shown that the combined activity of bupropion and naltrexone increase the firing rate of hypothalamic pro-opiomelanocortin (POMC) neurons and blockade of opioid receptor-mediated POMC auto-inhibition, which are associated with a reduction in food intake and increased energy expenditure. This combination was also found to reduce food intake when injected directly into the ventral tegmental area of the mesolimbic circuit in mice, which is an area associated with the regulation of reward pathways. •Mechanism of action (Drug B): The exact mechanism has not been established, however, based on electroencephalogram (EEG) studies, molindone is thought to act by occupying (antagonizing) dopamine (D2) receptor sites in the reticular limbic systems in the brain, thus decreasing dopamine activity. Decreased dopamine activity results in decreased physiological effects normally induced by excessive dopamine stimulation, such as those typically seen in manifestations of psychotic disorders. •Absorption (Drug A): Bupropion is currently available in 3 distinct, but bioequivalent formulations: immediate release (IR), sustained-release (SR), and extended-release (XL). Immediate Release Formulation In humans, following oral administration of bupropion hydrochloride tablets, peak plasma bupropion concentrations are usually achieved within 2 hours. IR formulations provide a short duration of action and are therefore generally dosed three times per day. Sustained Release Formulation In humans, following oral administration of bupropion hydrochloride sustained-release tablets (SR), peak plasma concentration (Cmax) of bupropion is usually achieved within 3 hours. SR formulations provide a 12-hour extended release of medication and are therefore generally dosed twice per day. Extended Release Formulation Following single oral administration of bupropion hydrochloride extended-release tablets (XL) to healthy volunteers, the median time to peak plasma concentrations for bupropion was approximately 5 hours. The presence of food did not affect the peak concentration or area under the curve of bupropion. XL formulations provide a 24-hour extended release of medication and are therefore generally dosed once per day/ In a trial comparing chronic dosing with bupropion hydrochloride extended-release tablets (SR) 150 mg twice daily to bupropion immediate-release formulation 100 mg 3 times daily, the steady state Cmax for bupropion after bupropion hydrochloride sustained-release tablets (SR) administration was approximately 85% of those achieved after bupropion immediate-release formulation administration. Exposure (AUC) to bupropion was equivalent for both formulations. Bioequivalence was also demonstrated for all three major active metabolites (i.e., hydroxybupropion, threohydrobupropion and erythrohydrobupropion) for both Cmax and AUC. Thus, at steady state, bupropion hydrochloride sustained-release tablets (SR) given twice daily, and the immediate-release formulation of bupropion given 3 times daily, are essentially bioequivalent for both bupropion and the 3 quantitatively important metabolites. Furthermore, in a study comparing 14-day dosing with bupropion hydrochloride extended-release tablets (XL), 300 mg once-daily to the immediate-release formulation of bupropion at 100 mg 3 times daily, equivalence was demonstrated for peak plasma concentration and area under the curve for bupropion and the three metabolites (hydroxybupropion, threohydrobupropion, and erythrohydrobupropion). Additionally, in a study comparing 14-day dosing with bupropion hydrochloride extended-release tablets (XL) 300 mg once daily to the sustained-release formulation of bupropion at 150 mg 2 times daily, equivalence was demonstrated for peak plasma concentration and area under the curve for bupropion and the three metabolites. Bupropion hydrochloride extended-release tablets (SR) can be taken with or without food. Bupropion Cmax and AUC were increased by 11% to 35% and 16% to 19%, respectively, when bupropion hydrochloride extended-release tablets (SR) was administered with food to healthy volunteers in three trials. The food effect is not considered clinically significant. Following a single-dose administration of bupropion hydrochloride extended-release tablets (SR) in humans, Cmax of bupropion's metabolite hydroxybupropion occurs approximately 6 hours post-dose and is approximately 10 times the peak level of the parent drug at steady state. The elimination half-life of hydroxybupropion is approximately 20 (±5) hours and its AUC at steady state is about 17 times that of bupropion. The times to peak concentrations for the erythrohydrobupropion and threohydrobupropion metabolites are similar to that of the hydroxybupropion metabolite. However, their elimination half-lives are longer, 33(±10) and 37 (±13) hours, respectively, and steady-state AUCs are 1.5 and 7 times that of bupropion, respectively. •Absorption (Drug B): Rapidly absorbed from the gastrointestinal tract following oral administration. •Volume of distribution (Drug A): No volume of distribution available •Volume of distribution (Drug B): No volume of distribution available •Protein binding (Drug A): In vitro tests show that bupropion is 84% bound to human plasma proteins at concentrations up to 200 mcg per mL. The extent of protein binding of the hydroxybupropion metabolite is similar to that for bupropion, whereas the extent of protein binding of the threohydrobupropion metabolite is about half that seen with bupropion. •Protein binding (Drug B): No protein binding available •Metabolism (Drug A): Bupropion is extensively metabolized in humans. Three metabolites are active: hydroxybupropion, which is formed via hydroxylation of the tert-butyl group of bupropion, and the amino-alcohol isomers, threohydrobupropion and erythrohydrobupropion, which are formed via reduction of the carbonyl group. In vitro findings suggest that CYP2B6 is the principal isoenzyme involved in the formation of hydroxybupropion, while cytochrome P450 enzymes are not involved in the formation of threohydrobupropion. Hydroxybupropion has been shown to have the same affinity as bupropion for the norepinephrine transporter (NET) but approximately 50% of its antidepressant activity despite reaching concentrations of ~10-fold higher than that of the parent drug. Oxidation of the bupropion side chain results in the formation of a glycine conjugate of meta-chlorobenzoic acid, which is then excreted as the major urinary metabolite. The potency and toxicity of the metabolites relative to bupropion have not been fully characterized. However, it has been demonstrated in an antidepressant screening test in mice that hydroxybupropion is one-half as potent as bupropion, while threohydrobupropion and erythrohydrobupropion are 5-fold less potent than bupropion. This may be of clinical importance because the plasma concentrations of the metabolites are as high as or higher than those of bupropion. Bupropion and its metabolites exhibit linear kinetics following chronic administration of 300 to 450 mg per day. •Metabolism (Drug B): Most likely hepatic. 36 metabolites have been recognized, some of which may be active. •Route of elimination (Drug A): Bupropion is extensively metabolized in humans. Oxidation of the bupropion side chain results in the formation of a glycine conjugate of metachlorobenzoic acid, which is then excreted as the major urinary metabolite. Following oral administration of 200 mg of 14C-bupropion in humans, 87% and 10% of the radioactive dose were recovered in the urine and feces, respectively. However, the fraction of the oral dose of bupropion excreted unchanged was only 0.5%, a finding consistent with the extensive metabolism of bupropion. •Route of elimination (Drug B): Human metabolic studies show molindone to be rapidly absorbed and metabolized when given orally. There are 36 recognized metabolites with less than 2-3% unmetabolized molindone being excreted in urine and feces. •Half-life (Drug A): 24 hours •Half-life (Drug B): No half-life available •Clearance (Drug A): No clearance available •Clearance (Drug B): No clearance available •Toxicity (Drug A): Symptoms of overdose include seizures, hallucinations, loss of consciousness, tachycardia, and cardiac arrest. •Toxicity (Drug B): No toxicity available •Brand Names (Drug A): Aplenzin, Auvelity, Budeprion, Contrave, Forfivo, Wellbutrin, Zyban •Brand Names (Drug B): No brand names available •Synonyms (Drug A): No synonyms listed •Synonyms (Drug B): No synonyms listed •Summary (Drug A): Bupropion is a norepinephrine and dopamine reuptake inhibitor used in the treatment of major depressive disorder (MDD), seasonal affective disorder (SAD), and as an aid to smoking cessation. •Summary (Drug B): Molindone is an antipsychotic used to treat schizophrenia.

Central nervous system (CNS) depressants can cause sedation, falls, respiratory depression, coma, and death.2,3 The potential interaction between a CNS depressant and another CNS depressant drug due to synergistic effects is well documented in the literature, although the risk and severity of CNS depression vary from each drug. The subject and affected drugs are both CNS depressants that, when co-administered, may result in a more profound CNS depression. As the risk and severity of CNS depression resulting from the combined use of CNS depressants vary from each agent, each interaction between CNS depressants should be considered individually. The severity of the interaction is moderate.

Question: Does Bupropion and Molindone interact? Information: •Drug A: Bupropion •Drug B: Molindone •Severity: MODERATE •Description: The risk or severity of CNS depression can be increased when Bupropion is combined with Molindone. •Extended Description: Central nervous system (CNS) depressants can cause sedation, falls, respiratory depression, coma, and death.2,3 The potential interaction between a CNS depressant and another CNS depressant drug due to synergistic effects is well documented in the literature, although the risk and severity of CNS depression vary from each drug. The subject and affected drugs are both CNS depressants that, when co-administered, may result in a more profound CNS depression. As the risk and severity of CNS depression resulting from the combined use of CNS depressants vary from each agent, each interaction between CNS depressants should be considered individually. •Indication (Drug A): Bupropion is indicated for the treatment of major depressive disorder (MDD), seasonal affective disorder (SAD), and as an aid to smoking cessation. When used in combination with naltrexone as the marketed product ContraveⓇ, bupropion is indicated as an adjunct to a reduced-calorie diet and increased physical activity for chronic weight management in adults with an initial body mass index (BMI) of: 30 kg/m^2 or greater (obese) or 27 kg/m^2 or greater (overweight) in the presence of at least one weight-related comorbid condition (e.g., hypertension, type 2 diabetes mellitus, or dyslipidemia). Bupropion is also used off-label as a first-line treatment in patients with ADHD and comorbid bipolar disorder when used as an adjunct to mood stabilizers. •Indication (Drug B): Molindone is used for the management of the manifestations of psychotic disorders. •Pharmacodynamics (Drug A): Bupropion is chemically unrelated to tricyclic, tetracyclic, selective serotonin re-uptake inhibitors, or other known antidepressant agents. Compared to classical tricyclic antidepressants, Bupropion is a relatively weak inhibitor of the neuronal uptake of norepinephrine and dopamine. In addition, Bupropion does not inhibit monoamine oxidase. Bupropion has been found to be essentially inactive at the serotonin transporter (SERT)(IC50 >10 000 nM), however both bupropion and its primary metabolite hydroxybupropion have been found to block the function of cation-selective serotonin type 3A receptors (5-HT3ARs). Bupropion produces dose-related central nervous system (CNS) stimulant effects in animals, as evidenced by increased locomotor activity, increased rates of responding in various schedule-controlled operant behaviour tasks, and, at high doses, induction of mild stereotyped behaviour. Due to these stimulant effects and selective activity at dopamine and norepinephrine receptors, bupropion has been identified as having an abuse potential. Bupropion has a similar structure to the controlled substance Cathinone, and has been identified as having mild amphetamine-like activity, particularly when inhaled or injected. Bupropion is also known to lower the seizure threshold, making any pre-existing seizure conditions a contraindication to its use. This risk is exacerbated when bupropion is combined with other drugs or substances that lower the seizure threshold, such as cocaine, or in clinical situations that would increase the risk of a seizure such as abrupt alcohol or benzodiazepine withdrawal. As norepinephrine has been shown to have anticonvulsant properties, bupropion's inhibitory effects on NET are thought to contribute to its pro-convulsant activity. Bupropion has been shown to increase blood pressure and pose a risk for exacerbation of unmanaged or pre-existing hypertension, however, clinical trials of bupropion in smokers with CVD have not identified an increased incidence of CV events including stroke or heart attack. In clinical trials, the mean increase in systolic blood pressure associated with the use of bupropion was found to be 1.3 mmHg. •Pharmacodynamics (Drug B): Molindone is a dihydroindolone compound which is not structurally related to the phenothiazines, the butyrophenones, or the thioxanthenes. Molindone has a pharmacological profile in laboratory animals which predominantly resembles that of major tranquilizers causing reduction of spontaneous locomotion and aggressiveness, suppression of a conditioned response and antagonism of the bizarre stereotyped behavior and hyperactivity induced by amphetamines. In addition, molindone antagonizes the depression caused by the tranquilizing agent tetrabenazine. •Mechanism of action (Drug A): Bupropion is a norepinephrine/dopamine-reuptake inhibitor (NDRI) that exerts its pharmacological effects by weakly inhibiting the enzymes involved in the uptake of the neurotransmitters norepinephrine and dopamine from the synaptic cleft, therefore prolonging their duration of action within the neuronal synapse and the downstream effects of these neurotransmitters. More specifically, bupropion binds to the norepinephrine transporter (NET) and the dopamine transporter (DAT). Bupropion was originally classified as an "atypical" antidepressant because it does not exert the same effects as the classical antidepressants such as Monoamine Oxidase Inhibitors (MAOIs), Tricyclic Antidepressants (TCAs), or Selective Serotonin Reuptake Inhibitors (SSRIs). While it has comparable effectiveness to typical first-line options for the treatment of depression such as SSRIs, bupropion is a unique option for the treatment of MDD as it lacks any clinically relevant serotonergic effects, typical of other mood medications, or any effects on histamine or adrenaline receptors. Lack of activity at these receptors results in a more tolerable side effect profile; bupropion is less likely to cause sexual side effects, sedation, or weight gain as compared to SSRIs or TCAs, for example. When used as an aid to smoking cessation, bupropion is thought to confer its anti-craving and anti-withdrawal effects by inhibiting dopamine reuptake, which is thought to be involved in the reward pathways associated with nicotine, and through the antagonism of the nicotinic acetylcholinergic receptor (AChR), thereby blunting the effects of nicotine. Furthermore, the stimulatory effects produced by bupropion in the central nervous system are similar to nicotine's effects, making low doses of bupropion a suitable option as a nicotine substitute. When used in combination with naltrexone in the marketed product ContraveⓇ for chronic weight management, the two components are thought to have effects on areas of the brain involved in the regulation of food intake. This includes the hypothalamus, which is involved in appetite regulation, and the mesolimbic dopamine circuit, which is involved in reward pathways. Studies have shown that the combined activity of bupropion and naltrexone increase the firing rate of hypothalamic pro-opiomelanocortin (POMC) neurons and blockade of opioid receptor-mediated POMC auto-inhibition, which are associated with a reduction in food intake and increased energy expenditure. This combination was also found to reduce food intake when injected directly into the ventral tegmental area of the mesolimbic circuit in mice, which is an area associated with the regulation of reward pathways. •Mechanism of action (Drug B): The exact mechanism has not been established, however, based on electroencephalogram (EEG) studies, molindone is thought to act by occupying (antagonizing) dopamine (D2) receptor sites in the reticular limbic systems in the brain, thus decreasing dopamine activity. Decreased dopamine activity results in decreased physiological effects normally induced by excessive dopamine stimulation, such as those typically seen in manifestations of psychotic disorders. •Absorption (Drug A): Bupropion is currently available in 3 distinct, but bioequivalent formulations: immediate release (IR), sustained-release (SR), and extended-release (XL). Immediate Release Formulation In humans, following oral administration of bupropion hydrochloride tablets, peak plasma bupropion concentrations are usually achieved within 2 hours. IR formulations provide a short duration of action and are therefore generally dosed three times per day. Sustained Release Formulation In humans, following oral administration of bupropion hydrochloride sustained-release tablets (SR), peak plasma concentration (Cmax) of bupropion is usually achieved within 3 hours. SR formulations provide a 12-hour extended release of medication and are therefore generally dosed twice per day. Extended Release Formulation Following single oral administration of bupropion hydrochloride extended-release tablets (XL) to healthy volunteers, the median time to peak plasma concentrations for bupropion was approximately 5 hours. The presence of food did not affect the peak concentration or area under the curve of bupropion. XL formulations provide a 24-hour extended release of medication and are therefore generally dosed once per day/ In a trial comparing chronic dosing with bupropion hydrochloride extended-release tablets (SR) 150 mg twice daily to bupropion immediate-release formulation 100 mg 3 times daily, the steady state Cmax for bupropion after bupropion hydrochloride sustained-release tablets (SR) administration was approximately 85% of those achieved after bupropion immediate-release formulation administration. Exposure (AUC) to bupropion was equivalent for both formulations. Bioequivalence was also demonstrated for all three major active metabolites (i.e., hydroxybupropion, threohydrobupropion and erythrohydrobupropion) for both Cmax and AUC. Thus, at steady state, bupropion hydrochloride sustained-release tablets (SR) given twice daily, and the immediate-release formulation of bupropion given 3 times daily, are essentially bioequivalent for both bupropion and the 3 quantitatively important metabolites. Furthermore, in a study comparing 14-day dosing with bupropion hydrochloride extended-release tablets (XL), 300 mg once-daily to the immediate-release formulation of bupropion at 100 mg 3 times daily, equivalence was demonstrated for peak plasma concentration and area under the curve for bupropion and the three metabolites (hydroxybupropion, threohydrobupropion, and erythrohydrobupropion). Additionally, in a study comparing 14-day dosing with bupropion hydrochloride extended-release tablets (XL) 300 mg once daily to the sustained-release formulation of bupropion at 150 mg 2 times daily, equivalence was demonstrated for peak plasma concentration and area under the curve for bupropion and the three metabolites. Bupropion hydrochloride extended-release tablets (SR) can be taken with or without food. Bupropion Cmax and AUC were increased by 11% to 35% and 16% to 19%, respectively, when bupropion hydrochloride extended-release tablets (SR) was administered with food to healthy volunteers in three trials. The food effect is not considered clinically significant. Following a single-dose administration of bupropion hydrochloride extended-release tablets (SR) in humans, Cmax of bupropion's metabolite hydroxybupropion occurs approximately 6 hours post-dose and is approximately 10 times the peak level of the parent drug at steady state. The elimination half-life of hydroxybupropion is approximately 20 (±5) hours and its AUC at steady state is about 17 times that of bupropion. The times to peak concentrations for the erythrohydrobupropion and threohydrobupropion metabolites are similar to that of the hydroxybupropion metabolite. However, their elimination half-lives are longer, 33(±10) and 37 (±13) hours, respectively, and steady-state AUCs are 1.5 and 7 times that of bupropion, respectively. •Absorption (Drug B): Rapidly absorbed from the gastrointestinal tract following oral administration. •Volume of distribution (Drug A): No volume of distribution available •Volume of distribution (Drug B): No volume of distribution available •Protein binding (Drug A): In vitro tests show that bupropion is 84% bound to human plasma proteins at concentrations up to 200 mcg per mL. The extent of protein binding of the hydroxybupropion metabolite is similar to that for bupropion, whereas the extent of protein binding of the threohydrobupropion metabolite is about half that seen with bupropion. •Protein binding (Drug B): No protein binding available •Metabolism (Drug A): Bupropion is extensively metabolized in humans. Three metabolites are active: hydroxybupropion, which is formed via hydroxylation of the tert-butyl group of bupropion, and the amino-alcohol isomers, threohydrobupropion and erythrohydrobupropion, which are formed via reduction of the carbonyl group. In vitro findings suggest that CYP2B6 is the principal isoenzyme involved in the formation of hydroxybupropion, while cytochrome P450 enzymes are not involved in the formation of threohydrobupropion. Hydroxybupropion has been shown to have the same affinity as bupropion for the norepinephrine transporter (NET) but approximately 50% of its antidepressant activity despite reaching concentrations of ~10-fold higher than that of the parent drug. Oxidation of the bupropion side chain results in the formation of a glycine conjugate of meta-chlorobenzoic acid, which is then excreted as the major urinary metabolite. The potency and toxicity of the metabolites relative to bupropion have not been fully characterized. However, it has been demonstrated in an antidepressant screening test in mice that hydroxybupropion is one-half as potent as bupropion, while threohydrobupropion and erythrohydrobupropion are 5-fold less potent than bupropion. This may be of clinical importance because the plasma concentrations of the metabolites are as high as or higher than those of bupropion. Bupropion and its metabolites exhibit linear kinetics following chronic administration of 300 to 450 mg per day. •Metabolism (Drug B): Most likely hepatic. 36 metabolites have been recognized, some of which may be active. •Route of elimination (Drug A): Bupropion is extensively metabolized in humans. Oxidation of the bupropion side chain results in the formation of a glycine conjugate of metachlorobenzoic acid, which is then excreted as the major urinary metabolite. Following oral administration of 200 mg of 14C-bupropion in humans, 87% and 10% of the radioactive dose were recovered in the urine and feces, respectively. However, the fraction of the oral dose of bupropion excreted unchanged was only 0.5%, a finding consistent with the extensive metabolism of bupropion. •Route of elimination (Drug B): Human metabolic studies show molindone to be rapidly absorbed and metabolized when given orally. There are 36 recognized metabolites with less than 2-3% unmetabolized molindone being excreted in urine and feces. •Half-life (Drug A): 24 hours •Half-life (Drug B): No half-life available •Clearance (Drug A): No clearance available •Clearance (Drug B): No clearance available •Toxicity (Drug A): Symptoms of overdose include seizures, hallucinations, loss of consciousness, tachycardia, and cardiac arrest. •Toxicity (Drug B): No toxicity available •Brand Names (Drug A): Aplenzin, Auvelity, Budeprion, Contrave, Forfivo, Wellbutrin, Zyban •Brand Names (Drug B): No brand names available •Synonyms (Drug A): No synonyms listed •Synonyms (Drug B): No synonyms listed •Summary (Drug A): Bupropion is a norepinephrine and dopamine reuptake inhibitor used in the treatment of major depressive disorder (MDD), seasonal affective disorder (SAD), and as an aid to smoking cessation. •Summary (Drug B): Molindone is an antipsychotic used to treat schizophrenia. Output: Central nervous system (CNS) depressants can cause sedation, falls, respiratory depression, coma, and death.2,3 The potential interaction between a CNS depressant and another CNS depressant drug due to synergistic effects is well documented in the literature, although the risk and severity of CNS depression vary from each drug. The subject and affected drugs are both CNS depressants that, when co-administered, may result in a more profound CNS depression. As the risk and severity of CNS depression resulting from the combined use of CNS depressants vary from each agent, each interaction between CNS depressants should be considered individually. The severity of the interaction is moderate.

Does Bupropion and Montelukast interact?

•Drug A: Bupropion •Drug B: Montelukast •Severity: MINOR •Description: The metabolism of Bupropion can be decreased when combined with Montelukast. •Extended Description: Both of these agents are reported to be metabolized by CYP2C9. Concomitant administration of multiple CYP2C9 substrates can result in competition for the CYP2C9 binding sites and consequently reduced metabolism and increased plasma levels of one or both of the affected drugs. Elevated plasma levels may result in a higher incidence and/or severity of adverse effects. •Indication (Drug A): Bupropion is indicated for the treatment of major depressive disorder (MDD), seasonal affective disorder (SAD), and as an aid to smoking cessation. When used in combination with naltrexone as the marketed product ContraveⓇ, bupropion is indicated as an adjunct to a reduced-calorie diet and increased physical activity for chronic weight management in adults with an initial body mass index (BMI) of: 30 kg/m^2 or greater (obese) or 27 kg/m^2 or greater (overweight) in the presence of at least one weight-related comorbid condition (e.g., hypertension, type 2 diabetes mellitus, or dyslipidemia). Bupropion is also used off-label as a first-line treatment in patients with ADHD and comorbid bipolar disorder when used as an adjunct to mood stabilizers. •Indication (Drug B): Montelukast is indicated for: (a) the prophylaxis and chronic treatment of asthma in adults and pediatric patients who are 12 months of age and older, although other regional health authorities specifically note this indication for adults and adolescents who are 15 years and older and also include indications for preventing day and night-time symptoms, and the treatment of acetylsalicylic acid-sensitive asthma; (b) the prevention of exercise-induced bronchoconstriction (EIB) in patients who are 6 years of age and older, although other regional health authorities specifically note this indication for adults and adolescents who are 15 years and older; and (c) the relief of symptoms of seasonal allergic rhinitis in patients 2 years of age and older and perennial allergic rhinitis in patients 6 months of age and older, although other regional health authorities specifically note the relief of seasonal allergic rhinitis symptoms for adults and adolescents who are 15 years and older. Furthermore, some formulations like chewable montelukast tablets may also be specifically indicated by particular regulatory bodies for the prophylaxis and chronic treatment of asthma, including the prevention of day and night-time symptoms, the treatment of acetylsalicylic acid based asthma, and the prevention of exercise-induced bronchoconstriction in adult and pediatric patients aged 2 and older, between the ages 2 and 5, or between the ages of 6 and 14 years. Moreover, when employed for such indications montelukast is considered effective as monotherapy or when combined with other medications indicated for the maintenance treatment of chronic asthma. For instance, montelukast and inhaled corticosteroids can be used concomitantly to demonstrate additive effects to control asthma or to decrease the necessary inhaled corticosteroid dose while still maintaining clinical stability. Additionally, in patients who continue to experience asthma symptoms, montelukast can also be combined with an 'as required' short-acting beta-agonist, an inhaled corticosteroid, or inhaled corticosteroid paired with a long-acting beta-agonist. •Pharmacodynamics (Drug A): Bupropion is chemically unrelated to tricyclic, tetracyclic, selective serotonin re-uptake inhibitors, or other known antidepressant agents. Compared to classical tricyclic antidepressants, Bupropion is a relatively weak inhibitor of the neuronal uptake of norepinephrine and dopamine. In addition, Bupropion does not inhibit monoamine oxidase. Bupropion has been found to be essentially inactive at the serotonin transporter (SERT)(IC50 >10 000 nM), however both bupropion and its primary metabolite hydroxybupropion have been found to block the function of cation-selective serotonin type 3A receptors (5-HT3ARs). Bupropion produces dose-related central nervous system (CNS) stimulant effects in animals, as evidenced by increased locomotor activity, increased rates of responding in various schedule-controlled operant behaviour tasks, and, at high doses, induction of mild stereotyped behaviour. Due to these stimulant effects and selective activity at dopamine and norepinephrine receptors, bupropion has been identified as having an abuse potential. Bupropion has a similar structure to the controlled substance Cathinone, and has been identified as having mild amphetamine-like activity, particularly when inhaled or injected. Bupropion is also known to lower the seizure threshold, making any pre-existing seizure conditions a contraindication to its use. This risk is exacerbated when bupropion is combined with other drugs or substances that lower the seizure threshold, such as cocaine, or in clinical situations that would increase the risk of a seizure such as abrupt alcohol or benzodiazepine withdrawal. As norepinephrine has been shown to have anticonvulsant properties, bupropion's inhibitory effects on NET are thought to contribute to its pro-convulsant activity. Bupropion has been shown to increase blood pressure and pose a risk for exacerbation of unmanaged or pre-existing hypertension, however, clinical trials of bupropion in smokers with CVD have not identified an increased incidence of CV events including stroke or heart attack. In clinical trials, the mean increase in systolic blood pressure associated with the use of bupropion was found to be 1.3 mmHg. •Pharmacodynamics (Drug B): Montelukast is a leukotriene receptor antagonist that demonstrates a marked affinity and selectivity to the cysteinyl leukotriene receptor type-1 in preference to many other crucial airway receptors like the prostanoid, cholinergic, or beta-adrenergic receptors. As a consequence, the agent can elicit substantial blockage of LTD4 leukotriene-mediated bronchoconstriction with doses as low as 5 mg. Moreover, a placebo-controlled, crossover study (n=12) demonstrated that montelukast is capable of inhibiting early and late phase bronchoconstriction caused by antigen challenge by 75% and 57% respectively. In particular, it has been documented that montelukast can cause bronchodilation as soon as within 2 hours of oral administration. This action can also be additive to the bronchodilation caused by the concomitant use of a beta agonist. Nevertheless, clinical investigations performed with adults 15 years of age and older revealed that no additional clinical benefit is obtained when doses of montelukast greater than 10 mg a day are used. Additionally, in clinical trials with adults and pediatric asthmatic patients aged 6 to 14 years, it was also determined that montelukast can reduce mean peripheral blood eosinophils by about 13% to 15% from baseline in comparison to placebo during double-blind treatment periods. At the same time, in patients aged 15 years and older who were experiencing seasonal allergic rhinitis, the use of montelukast caused a median reduction of 13% in peripheral blood eosinophil counts when compared to placebo as well. •Mechanism of action (Drug A): Bupropion is a norepinephrine/dopamine-reuptake inhibitor (NDRI) that exerts its pharmacological effects by weakly inhibiting the enzymes involved in the uptake of the neurotransmitters norepinephrine and dopamine from the synaptic cleft, therefore prolonging their duration of action within the neuronal synapse and the downstream effects of these neurotransmitters. More specifically, bupropion binds to the norepinephrine transporter (NET) and the dopamine transporter (DAT). Bupropion was originally classified as an "atypical" antidepressant because it does not exert the same effects as the classical antidepressants such as Monoamine Oxidase Inhibitors (MAOIs), Tricyclic Antidepressants (TCAs), or Selective Serotonin Reuptake Inhibitors (SSRIs). While it has comparable effectiveness to typical first-line options for the treatment of depression such as SSRIs, bupropion is a unique option for the treatment of MDD as it lacks any clinically relevant serotonergic effects, typical of other mood medications, or any effects on histamine or adrenaline receptors. Lack of activity at these receptors results in a more tolerable side effect profile; bupropion is less likely to cause sexual side effects, sedation, or weight gain as compared to SSRIs or TCAs, for example. When used as an aid to smoking cessation, bupropion is thought to confer its anti-craving and anti-withdrawal effects by inhibiting dopamine reuptake, which is thought to be involved in the reward pathways associated with nicotine, and through the antagonism of the nicotinic acetylcholinergic receptor (AChR), thereby blunting the effects of nicotine. Furthermore, the stimulatory effects produced by bupropion in the central nervous system are similar to nicotine's effects, making low doses of bupropion a suitable option as a nicotine substitute. When used in combination with naltrexone in the marketed product ContraveⓇ for chronic weight management, the two components are thought to have effects on areas of the brain involved in the regulation of food intake. This includes the hypothalamus, which is involved in appetite regulation, and the mesolimbic dopamine circuit, which is involved in reward pathways. Studies have shown that the combined activity of bupropion and naltrexone increase the firing rate of hypothalamic pro-opiomelanocortin (POMC) neurons and blockade of opioid receptor-mediated POMC auto-inhibition, which are associated with a reduction in food intake and increased energy expenditure. This combination was also found to reduce food intake when injected directly into the ventral tegmental area of the mesolimbic circuit in mice, which is an area associated with the regulation of reward pathways. •Mechanism of action (Drug B): Cysteinyl leukotrienes (CysLT) like LTC4, LTD4, and LTE4, among others, are eicosanoids released by a variety of cells like mast cells and eosinophils. When such CysLT bind to corresponding CysLT receptors like CysLT type-1 receptors located on respiratory airway smooth muscle cells, airway macrophages, and on various pro-inflammatory cells like eosinophils and some specific myeloid stem cells activities that facilitate the pathophysiology of asthma and allergic rhinitis are stimulated. In particular, CysLT-mediated airway bronchoconstriction, occluding mucous secretion, vascular permeability, and eosinophil recruitment are all types of effects that facilitate asthma. Alternatively, in allergic rhinitis, CysLTs are released by the nasal mucosa when exposed to allergens during both early and late phase reactions and participate in eliciting symptoms of allergic rhinitis like a congested nose and airway. Subsequently, montelukast is a leukotriene receptor antagonist that binds with high affinity and selectivity to the CysLT type 1 receptor, which consequently assists in inhibiting any physiological actions of CysLTs like LTC4, LTD4, and LTE4 at the receptor that may facilitate asthma or allergic rhinitis. •Absorption (Drug A): Bupropion is currently available in 3 distinct, but bioequivalent formulations: immediate release (IR), sustained-release (SR), and extended-release (XL). Immediate Release Formulation In humans, following oral administration of bupropion hydrochloride tablets, peak plasma bupropion concentrations are usually achieved within 2 hours. IR formulations provide a short duration of action and are therefore generally dosed three times per day. Sustained Release Formulation In humans, following oral administration of bupropion hydrochloride sustained-release tablets (SR), peak plasma concentration (Cmax) of bupropion is usually achieved within 3 hours. SR formulations provide a 12-hour extended release of medication and are therefore generally dosed twice per day. Extended Release Formulation Following single oral administration of bupropion hydrochloride extended-release tablets (XL) to healthy volunteers, the median time to peak plasma concentrations for bupropion was approximately 5 hours. The presence of food did not affect the peak concentration or area under the curve of bupropion. XL formulations provide a 24-hour extended release of medication and are therefore generally dosed once per day/ In a trial comparing chronic dosing with bupropion hydrochloride extended-release tablets (SR) 150 mg twice daily to bupropion immediate-release formulation 100 mg 3 times daily, the steady state Cmax for bupropion after bupropion hydrochloride sustained-release tablets (SR) administration was approximately 85% of those achieved after bupropion immediate-release formulation administration. Exposure (AUC) to bupropion was equivalent for both formulations. Bioequivalence was also demonstrated for all three major active metabolites (i.e., hydroxybupropion, threohydrobupropion and erythrohydrobupropion) for both Cmax and AUC. Thus, at steady state, bupropion hydrochloride sustained-release tablets (SR) given twice daily, and the immediate-release formulation of bupropion given 3 times daily, are essentially bioequivalent for both bupropion and the 3 quantitatively important metabolites. Furthermore, in a study comparing 14-day dosing with bupropion hydrochloride extended-release tablets (XL), 300 mg once-daily to the immediate-release formulation of bupropion at 100 mg 3 times daily, equivalence was demonstrated for peak plasma concentration and area under the curve for bupropion and the three metabolites (hydroxybupropion, threohydrobupropion, and erythrohydrobupropion). Additionally, in a study comparing 14-day dosing with bupropion hydrochloride extended-release tablets (XL) 300 mg once daily to the sustained-release formulation of bupropion at 150 mg 2 times daily, equivalence was demonstrated for peak plasma concentration and area under the curve for bupropion and the three metabolites. Bupropion hydrochloride extended-release tablets (SR) can be taken with or without food. Bupropion Cmax and AUC were increased by 11% to 35% and 16% to 19%, respectively, when bupropion hydrochloride extended-release tablets (SR) was administered with food to healthy volunteers in three trials. The food effect is not considered clinically significant. Following a single-dose administration of bupropion hydrochloride extended-release tablets (SR) in humans, Cmax of bupropion's metabolite hydroxybupropion occurs approximately 6 hours post-dose and is approximately 10 times the peak level of the parent drug at steady state. The elimination half-life of hydroxybupropion is approximately 20 (±5) hours and its AUC at steady state is about 17 times that of bupropion. The times to peak concentrations for the erythrohydrobupropion and threohydrobupropion metabolites are similar to that of the hydroxybupropion metabolite. However, their elimination half-lives are longer, 33(±10) and 37 (±13) hours, respectively, and steady-state AUCs are 1.5 and 7 times that of bupropion, respectively. •Absorption (Drug B): It has been observed that montelukast is quickly absorbed following administration by the oral route. The oral bioavailability documented for the drug is 64%. Furthermore, it seems that having a regular meal in the morning or even a high fat snack in the evening does not affect the absorption of montelukast. •Volume of distribution (Drug A): No volume of distribution available •Volume of distribution (Drug B): The steady-state volume of distribution recorded for montelukast is an average between 8 to 11 litres. •Protein binding (Drug A): In vitro tests show that bupropion is 84% bound to human plasma proteins at concentrations up to 200 mcg per mL. The extent of protein binding of the hydroxybupropion metabolite is similar to that for bupropion, whereas the extent of protein binding of the threohydrobupropion metabolite is about half that seen with bupropion. •Protein binding (Drug B): It has been determined that the protein binding of montelukast to plasma proteins exceeds 99%. •Metabolism (Drug A): Bupropion is extensively metabolized in humans. Three metabolites are active: hydroxybupropion, which is formed via hydroxylation of the tert-butyl group of bupropion, and the amino-alcohol isomers, threohydrobupropion and erythrohydrobupropion, which are formed via reduction of the carbonyl group. In vitro findings suggest that CYP2B6 is the principal isoenzyme involved in the formation of hydroxybupropion, while cytochrome P450 enzymes are not involved in the formation of threohydrobupropion. Hydroxybupropion has been shown to have the same affinity as bupropion for the norepinephrine transporter (NET) but approximately 50% of its antidepressant activity despite reaching concentrations of ~10-fold higher than that of the parent drug. Oxidation of the bupropion side chain results in the formation of a glycine conjugate of meta-chlorobenzoic acid, which is then excreted as the major urinary metabolite. The potency and toxicity of the metabolites relative to bupropion have not been fully characterized. However, it has been demonstrated in an antidepressant screening test in mice that hydroxybupropion is one-half as potent as bupropion, while threohydrobupropion and erythrohydrobupropion are 5-fold less potent than bupropion. This may be of clinical importance because the plasma concentrations of the metabolites are as high as or higher than those of bupropion. Bupropion and its metabolites exhibit linear kinetics following chronic administration of 300 to 450 mg per day. •Metabolism (Drug B): It has been determined that montelukast is highly metabolized and typically so by the cytochrome P450 3A4, 2C8, and 2C9 isoenzymes. In particular, it seems that the CYP2C8 enzymes play a significant role in the metabolism of the drug. Nevertheless, at therapeutic doses, the plasma concentrations of montelukast metabolites are undetectable at steady state in adults and pediatric patients. •Route of elimination (Drug A): Bupropion is extensively metabolized in humans. Oxidation of the bupropion side chain results in the formation of a glycine conjugate of metachlorobenzoic acid, which is then excreted as the major urinary metabolite. Following oral administration of 200 mg of 14C-bupropion in humans, 87% and 10% of the radioactive dose were recovered in the urine and feces, respectively. However, the fraction of the oral dose of bupropion excreted unchanged was only 0.5%, a finding consistent with the extensive metabolism of bupropion. •Route of elimination (Drug B): It has been reported that montelukast and its metabolites are almost exclusively excreted in the bile and into the feces. •Half-life (Drug A): 24 hours •Half-life (Drug B): Studies have demonstrated that the mean plasma half-life of montelukast varies from 2.7 to 5.5 hours when observed in healthy young adults. •Clearance (Drug A): No clearance available •Clearance (Drug B): The plasma clearance documented for montelukast is an average of 45 mL/min when observed in healthy adults. •Toxicity (Drug A): Symptoms of overdose include seizures, hallucinations, loss of consciousness, tachycardia, and cardiac arrest. •Toxicity (Drug B): The adverse effects associated with overdosage of montelukast include abdominal pain, somnolence, thirst, headache, vomiting, psychomotor hyperactivity, and less frequently, convulsion. The oral LD50 value determined for mice and rats is >5000 mg/kg. Montelukast has not been studied in pregnant women. Consequently, it should be used during pregnancy only if clearly needed. Additionally, as it is unknown whether montelukast is excreted into human breast milk, there is also caution regarding the use of the medication in nursing mothers. The plasma half-life of montelukast is somewhat prolonged in elderly patients, although no dosage adjustment is generally necessary. •Brand Names (Drug A): Aplenzin, Auvelity, Budeprion, Contrave, Forfivo, Wellbutrin, Zyban •Brand Names (Drug B): Singulair •Synonyms (Drug A): No synonyms listed •Synonyms (Drug B): Montelukast Montélukast Montelukastum •Summary (Drug A): Bupropion is a norepinephrine and dopamine reuptake inhibitor used in the treatment of major depressive disorder (MDD), seasonal affective disorder (SAD), and as an aid to smoking cessation. •Summary (Drug B): Montelukast is a leukotriene receptor antagonist used as part of an asthma therapy regimen, to prevent exercise induced bronchoconstriction, and to treat seasonal allergic rhinitis.

Both of these agents are reported to be metabolized by CYP2C9. Concomitant administration of multiple CYP2C9 substrates can result in competition for the CYP2C9 binding sites and consequently reduced metabolism and increased plasma levels of one or both of the affected drugs. Elevated plasma levels may result in a higher incidence and/or severity of adverse effects. The severity of the interaction is minor.

Question: Does Bupropion and Montelukast interact? Information: •Drug A: Bupropion •Drug B: Montelukast •Severity: MINOR •Description: The metabolism of Bupropion can be decreased when combined with Montelukast. •Extended Description: Both of these agents are reported to be metabolized by CYP2C9. Concomitant administration of multiple CYP2C9 substrates can result in competition for the CYP2C9 binding sites and consequently reduced metabolism and increased plasma levels of one or both of the affected drugs. Elevated plasma levels may result in a higher incidence and/or severity of adverse effects. •Indication (Drug A): Bupropion is indicated for the treatment of major depressive disorder (MDD), seasonal affective disorder (SAD), and as an aid to smoking cessation. When used in combination with naltrexone as the marketed product ContraveⓇ, bupropion is indicated as an adjunct to a reduced-calorie diet and increased physical activity for chronic weight management in adults with an initial body mass index (BMI) of: 30 kg/m^2 or greater (obese) or 27 kg/m^2 or greater (overweight) in the presence of at least one weight-related comorbid condition (e.g., hypertension, type 2 diabetes mellitus, or dyslipidemia). Bupropion is also used off-label as a first-line treatment in patients with ADHD and comorbid bipolar disorder when used as an adjunct to mood stabilizers. •Indication (Drug B): Montelukast is indicated for: (a) the prophylaxis and chronic treatment of asthma in adults and pediatric patients who are 12 months of age and older, although other regional health authorities specifically note this indication for adults and adolescents who are 15 years and older and also include indications for preventing day and night-time symptoms, and the treatment of acetylsalicylic acid-sensitive asthma; (b) the prevention of exercise-induced bronchoconstriction (EIB) in patients who are 6 years of age and older, although other regional health authorities specifically note this indication for adults and adolescents who are 15 years and older; and (c) the relief of symptoms of seasonal allergic rhinitis in patients 2 years of age and older and perennial allergic rhinitis in patients 6 months of age and older, although other regional health authorities specifically note the relief of seasonal allergic rhinitis symptoms for adults and adolescents who are 15 years and older. Furthermore, some formulations like chewable montelukast tablets may also be specifically indicated by particular regulatory bodies for the prophylaxis and chronic treatment of asthma, including the prevention of day and night-time symptoms, the treatment of acetylsalicylic acid based asthma, and the prevention of exercise-induced bronchoconstriction in adult and pediatric patients aged 2 and older, between the ages 2 and 5, or between the ages of 6 and 14 years. Moreover, when employed for such indications montelukast is considered effective as monotherapy or when combined with other medications indicated for the maintenance treatment of chronic asthma. For instance, montelukast and inhaled corticosteroids can be used concomitantly to demonstrate additive effects to control asthma or to decrease the necessary inhaled corticosteroid dose while still maintaining clinical stability. Additionally, in patients who continue to experience asthma symptoms, montelukast can also be combined with an 'as required' short-acting beta-agonist, an inhaled corticosteroid, or inhaled corticosteroid paired with a long-acting beta-agonist. •Pharmacodynamics (Drug A): Bupropion is chemically unrelated to tricyclic, tetracyclic, selective serotonin re-uptake inhibitors, or other known antidepressant agents. Compared to classical tricyclic antidepressants, Bupropion is a relatively weak inhibitor of the neuronal uptake of norepinephrine and dopamine. In addition, Bupropion does not inhibit monoamine oxidase. Bupropion has been found to be essentially inactive at the serotonin transporter (SERT)(IC50 >10 000 nM), however both bupropion and its primary metabolite hydroxybupropion have been found to block the function of cation-selective serotonin type 3A receptors (5-HT3ARs). Bupropion produces dose-related central nervous system (CNS) stimulant effects in animals, as evidenced by increased locomotor activity, increased rates of responding in various schedule-controlled operant behaviour tasks, and, at high doses, induction of mild stereotyped behaviour. Due to these stimulant effects and selective activity at dopamine and norepinephrine receptors, bupropion has been identified as having an abuse potential. Bupropion has a similar structure to the controlled substance Cathinone, and has been identified as having mild amphetamine-like activity, particularly when inhaled or injected. Bupropion is also known to lower the seizure threshold, making any pre-existing seizure conditions a contraindication to its use. This risk is exacerbated when bupropion is combined with other drugs or substances that lower the seizure threshold, such as cocaine, or in clinical situations that would increase the risk of a seizure such as abrupt alcohol or benzodiazepine withdrawal. As norepinephrine has been shown to have anticonvulsant properties, bupropion's inhibitory effects on NET are thought to contribute to its pro-convulsant activity. Bupropion has been shown to increase blood pressure and pose a risk for exacerbation of unmanaged or pre-existing hypertension, however, clinical trials of bupropion in smokers with CVD have not identified an increased incidence of CV events including stroke or heart attack. In clinical trials, the mean increase in systolic blood pressure associated with the use of bupropion was found to be 1.3 mmHg. •Pharmacodynamics (Drug B): Montelukast is a leukotriene receptor antagonist that demonstrates a marked affinity and selectivity to the cysteinyl leukotriene receptor type-1 in preference to many other crucial airway receptors like the prostanoid, cholinergic, or beta-adrenergic receptors. As a consequence, the agent can elicit substantial blockage of LTD4 leukotriene-mediated bronchoconstriction with doses as low as 5 mg. Moreover, a placebo-controlled, crossover study (n=12) demonstrated that montelukast is capable of inhibiting early and late phase bronchoconstriction caused by antigen challenge by 75% and 57% respectively. In particular, it has been documented that montelukast can cause bronchodilation as soon as within 2 hours of oral administration. This action can also be additive to the bronchodilation caused by the concomitant use of a beta agonist. Nevertheless, clinical investigations performed with adults 15 years of age and older revealed that no additional clinical benefit is obtained when doses of montelukast greater than 10 mg a day are used. Additionally, in clinical trials with adults and pediatric asthmatic patients aged 6 to 14 years, it was also determined that montelukast can reduce mean peripheral blood eosinophils by about 13% to 15% from baseline in comparison to placebo during double-blind treatment periods. At the same time, in patients aged 15 years and older who were experiencing seasonal allergic rhinitis, the use of montelukast caused a median reduction of 13% in peripheral blood eosinophil counts when compared to placebo as well. •Mechanism of action (Drug A): Bupropion is a norepinephrine/dopamine-reuptake inhibitor (NDRI) that exerts its pharmacological effects by weakly inhibiting the enzymes involved in the uptake of the neurotransmitters norepinephrine and dopamine from the synaptic cleft, therefore prolonging their duration of action within the neuronal synapse and the downstream effects of these neurotransmitters. More specifically, bupropion binds to the norepinephrine transporter (NET) and the dopamine transporter (DAT). Bupropion was originally classified as an "atypical" antidepressant because it does not exert the same effects as the classical antidepressants such as Monoamine Oxidase Inhibitors (MAOIs), Tricyclic Antidepressants (TCAs), or Selective Serotonin Reuptake Inhibitors (SSRIs). While it has comparable effectiveness to typical first-line options for the treatment of depression such as SSRIs, bupropion is a unique option for the treatment of MDD as it lacks any clinically relevant serotonergic effects, typical of other mood medications, or any effects on histamine or adrenaline receptors. Lack of activity at these receptors results in a more tolerable side effect profile; bupropion is less likely to cause sexual side effects, sedation, or weight gain as compared to SSRIs or TCAs, for example. When used as an aid to smoking cessation, bupropion is thought to confer its anti-craving and anti-withdrawal effects by inhibiting dopamine reuptake, which is thought to be involved in the reward pathways associated with nicotine, and through the antagonism of the nicotinic acetylcholinergic receptor (AChR), thereby blunting the effects of nicotine. Furthermore, the stimulatory effects produced by bupropion in the central nervous system are similar to nicotine's effects, making low doses of bupropion a suitable option as a nicotine substitute. When used in combination with naltrexone in the marketed product ContraveⓇ for chronic weight management, the two components are thought to have effects on areas of the brain involved in the regulation of food intake. This includes the hypothalamus, which is involved in appetite regulation, and the mesolimbic dopamine circuit, which is involved in reward pathways. Studies have shown that the combined activity of bupropion and naltrexone increase the firing rate of hypothalamic pro-opiomelanocortin (POMC) neurons and blockade of opioid receptor-mediated POMC auto-inhibition, which are associated with a reduction in food intake and increased energy expenditure. This combination was also found to reduce food intake when injected directly into the ventral tegmental area of the mesolimbic circuit in mice, which is an area associated with the regulation of reward pathways. •Mechanism of action (Drug B): Cysteinyl leukotrienes (CysLT) like LTC4, LTD4, and LTE4, among others, are eicosanoids released by a variety of cells like mast cells and eosinophils. When such CysLT bind to corresponding CysLT receptors like CysLT type-1 receptors located on respiratory airway smooth muscle cells, airway macrophages, and on various pro-inflammatory cells like eosinophils and some specific myeloid stem cells activities that facilitate the pathophysiology of asthma and allergic rhinitis are stimulated. In particular, CysLT-mediated airway bronchoconstriction, occluding mucous secretion, vascular permeability, and eosinophil recruitment are all types of effects that facilitate asthma. Alternatively, in allergic rhinitis, CysLTs are released by the nasal mucosa when exposed to allergens during both early and late phase reactions and participate in eliciting symptoms of allergic rhinitis like a congested nose and airway. Subsequently, montelukast is a leukotriene receptor antagonist that binds with high affinity and selectivity to the CysLT type 1 receptor, which consequently assists in inhibiting any physiological actions of CysLTs like LTC4, LTD4, and LTE4 at the receptor that may facilitate asthma or allergic rhinitis. •Absorption (Drug A): Bupropion is currently available in 3 distinct, but bioequivalent formulations: immediate release (IR), sustained-release (SR), and extended-release (XL). Immediate Release Formulation In humans, following oral administration of bupropion hydrochloride tablets, peak plasma bupropion concentrations are usually achieved within 2 hours. IR formulations provide a short duration of action and are therefore generally dosed three times per day. Sustained Release Formulation In humans, following oral administration of bupropion hydrochloride sustained-release tablets (SR), peak plasma concentration (Cmax) of bupropion is usually achieved within 3 hours. SR formulations provide a 12-hour extended release of medication and are therefore generally dosed twice per day. Extended Release Formulation Following single oral administration of bupropion hydrochloride extended-release tablets (XL) to healthy volunteers, the median time to peak plasma concentrations for bupropion was approximately 5 hours. The presence of food did not affect the peak concentration or area under the curve of bupropion. XL formulations provide a 24-hour extended release of medication and are therefore generally dosed once per day/ In a trial comparing chronic dosing with bupropion hydrochloride extended-release tablets (SR) 150 mg twice daily to bupropion immediate-release formulation 100 mg 3 times daily, the steady state Cmax for bupropion after bupropion hydrochloride sustained-release tablets (SR) administration was approximately 85% of those achieved after bupropion immediate-release formulation administration. Exposure (AUC) to bupropion was equivalent for both formulations. Bioequivalence was also demonstrated for all three major active metabolites (i.e., hydroxybupropion, threohydrobupropion and erythrohydrobupropion) for both Cmax and AUC. Thus, at steady state, bupropion hydrochloride sustained-release tablets (SR) given twice daily, and the immediate-release formulation of bupropion given 3 times daily, are essentially bioequivalent for both bupropion and the 3 quantitatively important metabolites. Furthermore, in a study comparing 14-day dosing with bupropion hydrochloride extended-release tablets (XL), 300 mg once-daily to the immediate-release formulation of bupropion at 100 mg 3 times daily, equivalence was demonstrated for peak plasma concentration and area under the curve for bupropion and the three metabolites (hydroxybupropion, threohydrobupropion, and erythrohydrobupropion). Additionally, in a study comparing 14-day dosing with bupropion hydrochloride extended-release tablets (XL) 300 mg once daily to the sustained-release formulation of bupropion at 150 mg 2 times daily, equivalence was demonstrated for peak plasma concentration and area under the curve for bupropion and the three metabolites. Bupropion hydrochloride extended-release tablets (SR) can be taken with or without food. Bupropion Cmax and AUC were increased by 11% to 35% and 16% to 19%, respectively, when bupropion hydrochloride extended-release tablets (SR) was administered with food to healthy volunteers in three trials. The food effect is not considered clinically significant. Following a single-dose administration of bupropion hydrochloride extended-release tablets (SR) in humans, Cmax of bupropion's metabolite hydroxybupropion occurs approximately 6 hours post-dose and is approximately 10 times the peak level of the parent drug at steady state. The elimination half-life of hydroxybupropion is approximately 20 (±5) hours and its AUC at steady state is about 17 times that of bupropion. The times to peak concentrations for the erythrohydrobupropion and threohydrobupropion metabolites are similar to that of the hydroxybupropion metabolite. However, their elimination half-lives are longer, 33(±10) and 37 (±13) hours, respectively, and steady-state AUCs are 1.5 and 7 times that of bupropion, respectively. •Absorption (Drug B): It has been observed that montelukast is quickly absorbed following administration by the oral route. The oral bioavailability documented for the drug is 64%. Furthermore, it seems that having a regular meal in the morning or even a high fat snack in the evening does not affect the absorption of montelukast. •Volume of distribution (Drug A): No volume of distribution available •Volume of distribution (Drug B): The steady-state volume of distribution recorded for montelukast is an average between 8 to 11 litres. •Protein binding (Drug A): In vitro tests show that bupropion is 84% bound to human plasma proteins at concentrations up to 200 mcg per mL. The extent of protein binding of the hydroxybupropion metabolite is similar to that for bupropion, whereas the extent of protein binding of the threohydrobupropion metabolite is about half that seen with bupropion. •Protein binding (Drug B): It has been determined that the protein binding of montelukast to plasma proteins exceeds 99%. •Metabolism (Drug A): Bupropion is extensively metabolized in humans. Three metabolites are active: hydroxybupropion, which is formed via hydroxylation of the tert-butyl group of bupropion, and the amino-alcohol isomers, threohydrobupropion and erythrohydrobupropion, which are formed via reduction of the carbonyl group. In vitro findings suggest that CYP2B6 is the principal isoenzyme involved in the formation of hydroxybupropion, while cytochrome P450 enzymes are not involved in the formation of threohydrobupropion. Hydroxybupropion has been shown to have the same affinity as bupropion for the norepinephrine transporter (NET) but approximately 50% of its antidepressant activity despite reaching concentrations of ~10-fold higher than that of the parent drug. Oxidation of the bupropion side chain results in the formation of a glycine conjugate of meta-chlorobenzoic acid, which is then excreted as the major urinary metabolite. The potency and toxicity of the metabolites relative to bupropion have not been fully characterized. However, it has been demonstrated in an antidepressant screening test in mice that hydroxybupropion is one-half as potent as bupropion, while threohydrobupropion and erythrohydrobupropion are 5-fold less potent than bupropion. This may be of clinical importance because the plasma concentrations of the metabolites are as high as or higher than those of bupropion. Bupropion and its metabolites exhibit linear kinetics following chronic administration of 300 to 450 mg per day. •Metabolism (Drug B): It has been determined that montelukast is highly metabolized and typically so by the cytochrome P450 3A4, 2C8, and 2C9 isoenzymes. In particular, it seems that the CYP2C8 enzymes play a significant role in the metabolism of the drug. Nevertheless, at therapeutic doses, the plasma concentrations of montelukast metabolites are undetectable at steady state in adults and pediatric patients. •Route of elimination (Drug A): Bupropion is extensively metabolized in humans. Oxidation of the bupropion side chain results in the formation of a glycine conjugate of metachlorobenzoic acid, which is then excreted as the major urinary metabolite. Following oral administration of 200 mg of 14C-bupropion in humans, 87% and 10% of the radioactive dose were recovered in the urine and feces, respectively. However, the fraction of the oral dose of bupropion excreted unchanged was only 0.5%, a finding consistent with the extensive metabolism of bupropion. •Route of elimination (Drug B): It has been reported that montelukast and its metabolites are almost exclusively excreted in the bile and into the feces. •Half-life (Drug A): 24 hours •Half-life (Drug B): Studies have demonstrated that the mean plasma half-life of montelukast varies from 2.7 to 5.5 hours when observed in healthy young adults. •Clearance (Drug A): No clearance available •Clearance (Drug B): The plasma clearance documented for montelukast is an average of 45 mL/min when observed in healthy adults. •Toxicity (Drug A): Symptoms of overdose include seizures, hallucinations, loss of consciousness, tachycardia, and cardiac arrest. •Toxicity (Drug B): The adverse effects associated with overdosage of montelukast include abdominal pain, somnolence, thirst, headache, vomiting, psychomotor hyperactivity, and less frequently, convulsion. The oral LD50 value determined for mice and rats is >5000 mg/kg. Montelukast has not been studied in pregnant women. Consequently, it should be used during pregnancy only if clearly needed. Additionally, as it is unknown whether montelukast is excreted into human breast milk, there is also caution regarding the use of the medication in nursing mothers. The plasma half-life of montelukast is somewhat prolonged in elderly patients, although no dosage adjustment is generally necessary. •Brand Names (Drug A): Aplenzin, Auvelity, Budeprion, Contrave, Forfivo, Wellbutrin, Zyban •Brand Names (Drug B): Singulair •Synonyms (Drug A): No synonyms listed •Synonyms (Drug B): Montelukast Montélukast Montelukastum •Summary (Drug A): Bupropion is a norepinephrine and dopamine reuptake inhibitor used in the treatment of major depressive disorder (MDD), seasonal affective disorder (SAD), and as an aid to smoking cessation. •Summary (Drug B): Montelukast is a leukotriene receptor antagonist used as part of an asthma therapy regimen, to prevent exercise induced bronchoconstriction, and to treat seasonal allergic rhinitis. Output: Both of these agents are reported to be metabolized by CYP2C9. Concomitant administration of multiple CYP2C9 substrates can result in competition for the CYP2C9 binding sites and consequently reduced metabolism and increased plasma levels of one or both of the affected drugs. Elevated plasma levels may result in a higher incidence and/or severity of adverse effects. The severity of the interaction is minor.

Does Bupropion and Morphine interact?

•Drug A: Bupropion •Drug B: Morphine •Severity: MODERATE •Description: The risk or severity of CNS depression can be increased when Morphine is combined with Bupropion. •Extended Description: Central nervous system (CNS) depressants can cause sedation, falls, respiratory depression, coma, and death.2,3 The potential interaction between a CNS depressant and another CNS depressant drug due to synergistic effects is well documented in the literature, although the risk and severity of CNS depression vary from each drug. The subject and affected drugs are both CNS depressants that, when co-administered, may result in a more profound CNS depression. As the risk and severity of CNS depression resulting from the combined use of CNS depressants vary from each agent, each interaction between CNS depressants should be considered individually. •Indication (Drug A): Bupropion is indicated for the treatment of major depressive disorder (MDD), seasonal affective disorder (SAD), and as an aid to smoking cessation. When used in combination with naltrexone as the marketed product ContraveⓇ, bupropion is indicated as an adjunct to a reduced-calorie diet and increased physical activity for chronic weight management in adults with an initial body mass index (BMI) of: 30 kg/m^2 or greater (obese) or 27 kg/m^2 or greater (overweight) in the presence of at least one weight-related comorbid condition (e.g., hypertension, type 2 diabetes mellitus, or dyslipidemia). Bupropion is also used off-label as a first-line treatment in patients with ADHD and comorbid bipolar disorder when used as an adjunct to mood stabilizers. •Indication (Drug B): Morphine is used for the management of chronic, moderate to severe pain. Opiods, including morphine, are effective for the short term management of pain. Patients taking opioids long term may need to be monitored for the development of physical dependence, addiction disorder, and drug abuse. •Pharmacodynamics (Drug A): Bupropion is chemically unrelated to tricyclic, tetracyclic, selective serotonin re-uptake inhibitors, or other known antidepressant agents. Compared to classical tricyclic antidepressants, Bupropion is a relatively weak inhibitor of the neuronal uptake of norepinephrine and dopamine. In addition, Bupropion does not inhibit monoamine oxidase. Bupropion has been found to be essentially inactive at the serotonin transporter (SERT)(IC50 >10 000 nM), however both bupropion and its primary metabolite hydroxybupropion have been found to block the function of cation-selective serotonin type 3A receptors (5-HT3ARs). Bupropion produces dose-related central nervous system (CNS) stimulant effects in animals, as evidenced by increased locomotor activity, increased rates of responding in various schedule-controlled operant behaviour tasks, and, at high doses, induction of mild stereotyped behaviour. Due to these stimulant effects and selective activity at dopamine and norepinephrine receptors, bupropion has been identified as having an abuse potential. Bupropion has a similar structure to the controlled substance Cathinone, and has been identified as having mild amphetamine-like activity, particularly when inhaled or injected. Bupropion is also known to lower the seizure threshold, making any pre-existing seizure conditions a contraindication to its use. This risk is exacerbated when bupropion is combined with other drugs or substances that lower the seizure threshold, such as cocaine, or in clinical situations that would increase the risk of a seizure such as abrupt alcohol or benzodiazepine withdrawal. As norepinephrine has been shown to have anticonvulsant properties, bupropion's inhibitory effects on NET are thought to contribute to its pro-convulsant activity. Bupropion has been shown to increase blood pressure and pose a risk for exacerbation of unmanaged or pre-existing hypertension, however, clinical trials of bupropion in smokers with CVD have not identified an increased incidence of CV events including stroke or heart attack. In clinical trials, the mean increase in systolic blood pressure associated with the use of bupropion was found to be 1.3 mmHg. •Pharmacodynamics (Drug B): Morphine binding to opioid receptors blocks transmission of nociceptive signals, signals pain-modulating neurons in the spinal cord, and inhibits primary afferent nociceptors to the dorsal horn sensory projection cells. Morphine has a time to onset of 6-30 minutes. Excess consumption of morphine and other opioids can lead to changes in synaptic neuroplasticity, including changes in neuron density, changes at postsynaptic sites, and changes at dendritic terminals. Intravenous morphine's analgesic effect is sex dependent. The EC 50 in men is 76ng/mL and in women is 22ng/mL. Morphine-6-glucuronide is 22 times less potent than morphine in eliciting pupil constriction. •Mechanism of action (Drug A): Bupropion is a norepinephrine/dopamine-reuptake inhibitor (NDRI) that exerts its pharmacological effects by weakly inhibiting the enzymes involved in the uptake of the neurotransmitters norepinephrine and dopamine from the synaptic cleft, therefore prolonging their duration of action within the neuronal synapse and the downstream effects of these neurotransmitters. More specifically, bupropion binds to the norepinephrine transporter (NET) and the dopamine transporter (DAT). Bupropion was originally classified as an "atypical" antidepressant because it does not exert the same effects as the classical antidepressants such as Monoamine Oxidase Inhibitors (MAOIs), Tricyclic Antidepressants (TCAs), or Selective Serotonin Reuptake Inhibitors (SSRIs). While it has comparable effectiveness to typical first-line options for the treatment of depression such as SSRIs, bupropion is a unique option for the treatment of MDD as it lacks any clinically relevant serotonergic effects, typical of other mood medications, or any effects on histamine or adrenaline receptors. Lack of activity at these receptors results in a more tolerable side effect profile; bupropion is less likely to cause sexual side effects, sedation, or weight gain as compared to SSRIs or TCAs, for example. When used as an aid to smoking cessation, bupropion is thought to confer its anti-craving and anti-withdrawal effects by inhibiting dopamine reuptake, which is thought to be involved in the reward pathways associated with nicotine, and through the antagonism of the nicotinic acetylcholinergic receptor (AChR), thereby blunting the effects of nicotine. Furthermore, the stimulatory effects produced by bupropion in the central nervous system are similar to nicotine's effects, making low doses of bupropion a suitable option as a nicotine substitute. When used in combination with naltrexone in the marketed product ContraveⓇ for chronic weight management, the two components are thought to have effects on areas of the brain involved in the regulation of food intake. This includes the hypothalamus, which is involved in appetite regulation, and the mesolimbic dopamine circuit, which is involved in reward pathways. Studies have shown that the combined activity of bupropion and naltrexone increase the firing rate of hypothalamic pro-opiomelanocortin (POMC) neurons and blockade of opioid receptor-mediated POMC auto-inhibition, which are associated with a reduction in food intake and increased energy expenditure. This combination was also found to reduce food intake when injected directly into the ventral tegmental area of the mesolimbic circuit in mice, which is an area associated with the regulation of reward pathways. •Mechanism of action (Drug B): Morphine-6-glucuronide is responsible for approximately 85% of the response observed by morphine administration. Morphine and its metabolites act as agonists of the mu and kappa opioid receptors. The mu-opioid receptor is integral to morphine's effects on the ventral tegmental area of the brain. Morphine's activation of the reward pathway is mediated by agonism of the delta-opioid receptor in the nucleus accumbens, while modification of the respiratory system and addiction disorder are mediated by agonism of the mu-opioid receptor. •Absorption (Drug A): Bupropion is currently available in 3 distinct, but bioequivalent formulations: immediate release (IR), sustained-release (SR), and extended-release (XL). Immediate Release Formulation In humans, following oral administration of bupropion hydrochloride tablets, peak plasma bupropion concentrations are usually achieved within 2 hours. IR formulations provide a short duration of action and are therefore generally dosed three times per day. Sustained Release Formulation In humans, following oral administration of bupropion hydrochloride sustained-release tablets (SR), peak plasma concentration (Cmax) of bupropion is usually achieved within 3 hours. SR formulations provide a 12-hour extended release of medication and are therefore generally dosed twice per day. Extended Release Formulation Following single oral administration of bupropion hydrochloride extended-release tablets (XL) to healthy volunteers, the median time to peak plasma concentrations for bupropion was approximately 5 hours. The presence of food did not affect the peak concentration or area under the curve of bupropion. XL formulations provide a 24-hour extended release of medication and are therefore generally dosed once per day/ In a trial comparing chronic dosing with bupropion hydrochloride extended-release tablets (SR) 150 mg twice daily to bupropion immediate-release formulation 100 mg 3 times daily, the steady state Cmax for bupropion after bupropion hydrochloride sustained-release tablets (SR) administration was approximately 85% of those achieved after bupropion immediate-release formulation administration. Exposure (AUC) to bupropion was equivalent for both formulations. Bioequivalence was also demonstrated for all three major active metabolites (i.e., hydroxybupropion, threohydrobupropion and erythrohydrobupropion) for both Cmax and AUC. Thus, at steady state, bupropion hydrochloride sustained-release tablets (SR) given twice daily, and the immediate-release formulation of bupropion given 3 times daily, are essentially bioequivalent for both bupropion and the 3 quantitatively important metabolites. Furthermore, in a study comparing 14-day dosing with bupropion hydrochloride extended-release tablets (XL), 300 mg once-daily to the immediate-release formulation of bupropion at 100 mg 3 times daily, equivalence was demonstrated for peak plasma concentration and area under the curve for bupropion and the three metabolites (hydroxybupropion, threohydrobupropion, and erythrohydrobupropion). Additionally, in a study comparing 14-day dosing with bupropion hydrochloride extended-release tablets (XL) 300 mg once daily to the sustained-release formulation of bupropion at 150 mg 2 times daily, equivalence was demonstrated for peak plasma concentration and area under the curve for bupropion and the three metabolites. Bupropion hydrochloride extended-release tablets (SR) can be taken with or without food. Bupropion Cmax and AUC were increased by 11% to 35% and 16% to 19%, respectively, when bupropion hydrochloride extended-release tablets (SR) was administered with food to healthy volunteers in three trials. The food effect is not considered clinically significant. Following a single-dose administration of bupropion hydrochloride extended-release tablets (SR) in humans, Cmax of bupropion's metabolite hydroxybupropion occurs approximately 6 hours post-dose and is approximately 10 times the peak level of the parent drug at steady state. The elimination half-life of hydroxybupropion is approximately 20 (±5) hours and its AUC at steady state is about 17 times that of bupropion. The times to peak concentrations for the erythrohydrobupropion and threohydrobupropion metabolites are similar to that of the hydroxybupropion metabolite. However, their elimination half-lives are longer, 33(±10) and 37 (±13) hours, respectively, and steady-state AUCs are 1.5 and 7 times that of bupropion, respectively. •Absorption (Drug B): Morphine is absorbed in the alkaline environments of the upper intestine and rectal mucosa. The bioavailability of morphine is 80-100%. There is significant first-pass metabolism, therefore oral doses are 6 times larger than parenteral doses to achieve the same effect. Morphine reaches steady-state concentrations after 24-48 hours. Parenteral morphine has a T max of 15 minutes and oral morphine has a T max of 90 minutes, with a C max of 283nmol/L. The AUC of morphine is 225-290nmol*h/L. •Volume of distribution (Drug A): No volume of distribution available •Volume of distribution (Drug B): The volume of distribution of morphine is 5.31L/kg. Morphine-6-glucuronide has a volume of distribution of 3.61L/kg. •Protein binding (Drug A): In vitro tests show that bupropion is 84% bound to human plasma proteins at concentrations up to 200 mcg per mL. The extent of protein binding of the hydroxybupropion metabolite is similar to that for bupropion, whereas the extent of protein binding of the threohydrobupropion metabolite is about half that seen with bupropion. •Protein binding (Drug B): Morphine is 35% protein bound, the metabolite morphine-3-glucuronide is 10% protein bound, and morphine-6-glucuronide is 15% protein bound. •Metabolism (Drug A): Bupropion is extensively metabolized in humans. Three metabolites are active: hydroxybupropion, which is formed via hydroxylation of the tert-butyl group of bupropion, and the amino-alcohol isomers, threohydrobupropion and erythrohydrobupropion, which are formed via reduction of the carbonyl group. In vitro findings suggest that CYP2B6 is the principal isoenzyme involved in the formation of hydroxybupropion, while cytochrome P450 enzymes are not involved in the formation of threohydrobupropion. Hydroxybupropion has been shown to have the same affinity as bupropion for the norepinephrine transporter (NET) but approximately 50% of its antidepressant activity despite reaching concentrations of ~10-fold higher than that of the parent drug. Oxidation of the bupropion side chain results in the formation of a glycine conjugate of meta-chlorobenzoic acid, which is then excreted as the major urinary metabolite. The potency and toxicity of the metabolites relative to bupropion have not been fully characterized. However, it has been demonstrated in an antidepressant screening test in mice that hydroxybupropion is one-half as potent as bupropion, while threohydrobupropion and erythrohydrobupropion are 5-fold less potent than bupropion. This may be of clinical importance because the plasma concentrations of the metabolites are as high as or higher than those of bupropion. Bupropion and its metabolites exhibit linear kinetics following chronic administration of 300 to 450 mg per day. •Metabolism (Drug B): Morphine is 90% metabolized by glucuronidation by UGT2B7 and sulfation at positions 3 and 6. Morphine can also be metabolized to codeine, normorphine, and morphine ethereal sulfate. •Route of elimination (Drug A): Bupropion is extensively metabolized in humans. Oxidation of the bupropion side chain results in the formation of a glycine conjugate of metachlorobenzoic acid, which is then excreted as the major urinary metabolite. Following oral administration of 200 mg of 14C-bupropion in humans, 87% and 10% of the radioactive dose were recovered in the urine and feces, respectively. However, the fraction of the oral dose of bupropion excreted unchanged was only 0.5%, a finding consistent with the extensive metabolism of bupropion. •Route of elimination (Drug B): 70-80% of an administered dose is excreted within 48 hours. Morphine is predominantly eliminated in the urine with 2-10% of a dose recovered as the unchanged parent drug. 7-10% of a dose of morphine is eliminated in the feces. •Half-life (Drug A): 24 hours •Half-life (Drug B): Morphine has a half life of 2-3 hours. •Clearance (Drug A): No clearance available •Clearance (Drug B): The apparent clearance of intravenous or subcutaneous morphine is 1600 mL/min. •Toxicity (Drug A): Symptoms of overdose include seizures, hallucinations, loss of consciousness, tachycardia, and cardiac arrest. •Toxicity (Drug B): The LD 50 is 0.78µg/mL in males and 0.98µg/mL in females. Patients experiencing an overdose present with respiratory depression, somnolence, skeletal muscle flaccidity, cold and clammy skin, miosis, and mydriasis. Symptoms of overdose can progress to pulmonary edema, bradycardia, hypotension, cardiac arrest, and death. Treat overdose with symptomatic and supportive treatment which may include the use of oxygen, vasopressors, and naloxone. •Brand Names (Drug A): Aplenzin, Auvelity, Budeprion, Contrave, Forfivo, Wellbutrin, Zyban •Brand Names (Drug B): Arymo, Avinza, Doloral, Duramorph, Embeda, Infumorph, Kadian, M-ediat, M-eslon, MSIR, Mitigo, Ms Contin, Statex •Synonyms (Drug A): No synonyms listed •Synonyms (Drug B): Morfina Morphia Morphin Morphine Morphinum Morphium •Summary (Drug A): Bupropion is a norepinephrine and dopamine reuptake inhibitor used in the treatment of major depressive disorder (MDD), seasonal affective disorder (SAD), and as an aid to smoking cessation. •Summary (Drug B): Morphine is an opioid agonist used for the relief of moderate to severe acute and chronic pain.

Central nervous system (CNS) depressants can cause sedation, falls, respiratory depression, coma, and death.2,3 The potential interaction between a CNS depressant and another CNS depressant drug due to synergistic effects is well documented in the literature, although the risk and severity of CNS depression vary from each drug. The subject and affected drugs are both CNS depressants that, when co-administered, may result in a more profound CNS depression. As the risk and severity of CNS depression resulting from the combined use of CNS depressants vary from each agent, each interaction between CNS depressants should be considered individually. The severity of the interaction is moderate.

Question: Does Bupropion and Morphine interact? Information: •Drug A: Bupropion •Drug B: Morphine •Severity: MODERATE •Description: The risk or severity of CNS depression can be increased when Morphine is combined with Bupropion. •Extended Description: Central nervous system (CNS) depressants can cause sedation, falls, respiratory depression, coma, and death.2,3 The potential interaction between a CNS depressant and another CNS depressant drug due to synergistic effects is well documented in the literature, although the risk and severity of CNS depression vary from each drug. The subject and affected drugs are both CNS depressants that, when co-administered, may result in a more profound CNS depression. As the risk and severity of CNS depression resulting from the combined use of CNS depressants vary from each agent, each interaction between CNS depressants should be considered individually. •Indication (Drug A): Bupropion is indicated for the treatment of major depressive disorder (MDD), seasonal affective disorder (SAD), and as an aid to smoking cessation. When used in combination with naltrexone as the marketed product ContraveⓇ, bupropion is indicated as an adjunct to a reduced-calorie diet and increased physical activity for chronic weight management in adults with an initial body mass index (BMI) of: 30 kg/m^2 or greater (obese) or 27 kg/m^2 or greater (overweight) in the presence of at least one weight-related comorbid condition (e.g., hypertension, type 2 diabetes mellitus, or dyslipidemia). Bupropion is also used off-label as a first-line treatment in patients with ADHD and comorbid bipolar disorder when used as an adjunct to mood stabilizers. •Indication (Drug B): Morphine is used for the management of chronic, moderate to severe pain. Opiods, including morphine, are effective for the short term management of pain. Patients taking opioids long term may need to be monitored for the development of physical dependence, addiction disorder, and drug abuse. •Pharmacodynamics (Drug A): Bupropion is chemically unrelated to tricyclic, tetracyclic, selective serotonin re-uptake inhibitors, or other known antidepressant agents. Compared to classical tricyclic antidepressants, Bupropion is a relatively weak inhibitor of the neuronal uptake of norepinephrine and dopamine. In addition, Bupropion does not inhibit monoamine oxidase. Bupropion has been found to be essentially inactive at the serotonin transporter (SERT)(IC50 >10 000 nM), however both bupropion and its primary metabolite hydroxybupropion have been found to block the function of cation-selective serotonin type 3A receptors (5-HT3ARs). Bupropion produces dose-related central nervous system (CNS) stimulant effects in animals, as evidenced by increased locomotor activity, increased rates of responding in various schedule-controlled operant behaviour tasks, and, at high doses, induction of mild stereotyped behaviour. Due to these stimulant effects and selective activity at dopamine and norepinephrine receptors, bupropion has been identified as having an abuse potential. Bupropion has a similar structure to the controlled substance Cathinone, and has been identified as having mild amphetamine-like activity, particularly when inhaled or injected. Bupropion is also known to lower the seizure threshold, making any pre-existing seizure conditions a contraindication to its use. This risk is exacerbated when bupropion is combined with other drugs or substances that lower the seizure threshold, such as cocaine, or in clinical situations that would increase the risk of a seizure such as abrupt alcohol or benzodiazepine withdrawal. As norepinephrine has been shown to have anticonvulsant properties, bupropion's inhibitory effects on NET are thought to contribute to its pro-convulsant activity. Bupropion has been shown to increase blood pressure and pose a risk for exacerbation of unmanaged or pre-existing hypertension, however, clinical trials of bupropion in smokers with CVD have not identified an increased incidence of CV events including stroke or heart attack. In clinical trials, the mean increase in systolic blood pressure associated with the use of bupropion was found to be 1.3 mmHg. •Pharmacodynamics (Drug B): Morphine binding to opioid receptors blocks transmission of nociceptive signals, signals pain-modulating neurons in the spinal cord, and inhibits primary afferent nociceptors to the dorsal horn sensory projection cells. Morphine has a time to onset of 6-30 minutes. Excess consumption of morphine and other opioids can lead to changes in synaptic neuroplasticity, including changes in neuron density, changes at postsynaptic sites, and changes at dendritic terminals. Intravenous morphine's analgesic effect is sex dependent. The EC 50 in men is 76ng/mL and in women is 22ng/mL. Morphine-6-glucuronide is 22 times less potent than morphine in eliciting pupil constriction. •Mechanism of action (Drug A): Bupropion is a norepinephrine/dopamine-reuptake inhibitor (NDRI) that exerts its pharmacological effects by weakly inhibiting the enzymes involved in the uptake of the neurotransmitters norepinephrine and dopamine from the synaptic cleft, therefore prolonging their duration of action within the neuronal synapse and the downstream effects of these neurotransmitters. More specifically, bupropion binds to the norepinephrine transporter (NET) and the dopamine transporter (DAT). Bupropion was originally classified as an "atypical" antidepressant because it does not exert the same effects as the classical antidepressants such as Monoamine Oxidase Inhibitors (MAOIs), Tricyclic Antidepressants (TCAs), or Selective Serotonin Reuptake Inhibitors (SSRIs). While it has comparable effectiveness to typical first-line options for the treatment of depression such as SSRIs, bupropion is a unique option for the treatment of MDD as it lacks any clinically relevant serotonergic effects, typical of other mood medications, or any effects on histamine or adrenaline receptors. Lack of activity at these receptors results in a more tolerable side effect profile; bupropion is less likely to cause sexual side effects, sedation, or weight gain as compared to SSRIs or TCAs, for example. When used as an aid to smoking cessation, bupropion is thought to confer its anti-craving and anti-withdrawal effects by inhibiting dopamine reuptake, which is thought to be involved in the reward pathways associated with nicotine, and through the antagonism of the nicotinic acetylcholinergic receptor (AChR), thereby blunting the effects of nicotine. Furthermore, the stimulatory effects produced by bupropion in the central nervous system are similar to nicotine's effects, making low doses of bupropion a suitable option as a nicotine substitute. When used in combination with naltrexone in the marketed product ContraveⓇ for chronic weight management, the two components are thought to have effects on areas of the brain involved in the regulation of food intake. This includes the hypothalamus, which is involved in appetite regulation, and the mesolimbic dopamine circuit, which is involved in reward pathways. Studies have shown that the combined activity of bupropion and naltrexone increase the firing rate of hypothalamic pro-opiomelanocortin (POMC) neurons and blockade of opioid receptor-mediated POMC auto-inhibition, which are associated with a reduction in food intake and increased energy expenditure. This combination was also found to reduce food intake when injected directly into the ventral tegmental area of the mesolimbic circuit in mice, which is an area associated with the regulation of reward pathways. •Mechanism of action (Drug B): Morphine-6-glucuronide is responsible for approximately 85% of the response observed by morphine administration. Morphine and its metabolites act as agonists of the mu and kappa opioid receptors. The mu-opioid receptor is integral to morphine's effects on the ventral tegmental area of the brain. Morphine's activation of the reward pathway is mediated by agonism of the delta-opioid receptor in the nucleus accumbens, while modification of the respiratory system and addiction disorder are mediated by agonism of the mu-opioid receptor. •Absorption (Drug A): Bupropion is currently available in 3 distinct, but bioequivalent formulations: immediate release (IR), sustained-release (SR), and extended-release (XL). Immediate Release Formulation In humans, following oral administration of bupropion hydrochloride tablets, peak plasma bupropion concentrations are usually achieved within 2 hours. IR formulations provide a short duration of action and are therefore generally dosed three times per day. Sustained Release Formulation In humans, following oral administration of bupropion hydrochloride sustained-release tablets (SR), peak plasma concentration (Cmax) of bupropion is usually achieved within 3 hours. SR formulations provide a 12-hour extended release of medication and are therefore generally dosed twice per day. Extended Release Formulation Following single oral administration of bupropion hydrochloride extended-release tablets (XL) to healthy volunteers, the median time to peak plasma concentrations for bupropion was approximately 5 hours. The presence of food did not affect the peak concentration or area under the curve of bupropion. XL formulations provide a 24-hour extended release of medication and are therefore generally dosed once per day/ In a trial comparing chronic dosing with bupropion hydrochloride extended-release tablets (SR) 150 mg twice daily to bupropion immediate-release formulation 100 mg 3 times daily, the steady state Cmax for bupropion after bupropion hydrochloride sustained-release tablets (SR) administration was approximately 85% of those achieved after bupropion immediate-release formulation administration. Exposure (AUC) to bupropion was equivalent for both formulations. Bioequivalence was also demonstrated for all three major active metabolites (i.e., hydroxybupropion, threohydrobupropion and erythrohydrobupropion) for both Cmax and AUC. Thus, at steady state, bupropion hydrochloride sustained-release tablets (SR) given twice daily, and the immediate-release formulation of bupropion given 3 times daily, are essentially bioequivalent for both bupropion and the 3 quantitatively important metabolites. Furthermore, in a study comparing 14-day dosing with bupropion hydrochloride extended-release tablets (XL), 300 mg once-daily to the immediate-release formulation of bupropion at 100 mg 3 times daily, equivalence was demonstrated for peak plasma concentration and area under the curve for bupropion and the three metabolites (hydroxybupropion, threohydrobupropion, and erythrohydrobupropion). Additionally, in a study comparing 14-day dosing with bupropion hydrochloride extended-release tablets (XL) 300 mg once daily to the sustained-release formulation of bupropion at 150 mg 2 times daily, equivalence was demonstrated for peak plasma concentration and area under the curve for bupropion and the three metabolites. Bupropion hydrochloride extended-release tablets (SR) can be taken with or without food. Bupropion Cmax and AUC were increased by 11% to 35% and 16% to 19%, respectively, when bupropion hydrochloride extended-release tablets (SR) was administered with food to healthy volunteers in three trials. The food effect is not considered clinically significant. Following a single-dose administration of bupropion hydrochloride extended-release tablets (SR) in humans, Cmax of bupropion's metabolite hydroxybupropion occurs approximately 6 hours post-dose and is approximately 10 times the peak level of the parent drug at steady state. The elimination half-life of hydroxybupropion is approximately 20 (±5) hours and its AUC at steady state is about 17 times that of bupropion. The times to peak concentrations for the erythrohydrobupropion and threohydrobupropion metabolites are similar to that of the hydroxybupropion metabolite. However, their elimination half-lives are longer, 33(±10) and 37 (±13) hours, respectively, and steady-state AUCs are 1.5 and 7 times that of bupropion, respectively. •Absorption (Drug B): Morphine is absorbed in the alkaline environments of the upper intestine and rectal mucosa. The bioavailability of morphine is 80-100%. There is significant first-pass metabolism, therefore oral doses are 6 times larger than parenteral doses to achieve the same effect. Morphine reaches steady-state concentrations after 24-48 hours. Parenteral morphine has a T max of 15 minutes and oral morphine has a T max of 90 minutes, with a C max of 283nmol/L. The AUC of morphine is 225-290nmol*h/L. •Volume of distribution (Drug A): No volume of distribution available •Volume of distribution (Drug B): The volume of distribution of morphine is 5.31L/kg. Morphine-6-glucuronide has a volume of distribution of 3.61L/kg. •Protein binding (Drug A): In vitro tests show that bupropion is 84% bound to human plasma proteins at concentrations up to 200 mcg per mL. The extent of protein binding of the hydroxybupropion metabolite is similar to that for bupropion, whereas the extent of protein binding of the threohydrobupropion metabolite is about half that seen with bupropion. •Protein binding (Drug B): Morphine is 35% protein bound, the metabolite morphine-3-glucuronide is 10% protein bound, and morphine-6-glucuronide is 15% protein bound. •Metabolism (Drug A): Bupropion is extensively metabolized in humans. Three metabolites are active: hydroxybupropion, which is formed via hydroxylation of the tert-butyl group of bupropion, and the amino-alcohol isomers, threohydrobupropion and erythrohydrobupropion, which are formed via reduction of the carbonyl group. In vitro findings suggest that CYP2B6 is the principal isoenzyme involved in the formation of hydroxybupropion, while cytochrome P450 enzymes are not involved in the formation of threohydrobupropion. Hydroxybupropion has been shown to have the same affinity as bupropion for the norepinephrine transporter (NET) but approximately 50% of its antidepressant activity despite reaching concentrations of ~10-fold higher than that of the parent drug. Oxidation of the bupropion side chain results in the formation of a glycine conjugate of meta-chlorobenzoic acid, which is then excreted as the major urinary metabolite. The potency and toxicity of the metabolites relative to bupropion have not been fully characterized. However, it has been demonstrated in an antidepressant screening test in mice that hydroxybupropion is one-half as potent as bupropion, while threohydrobupropion and erythrohydrobupropion are 5-fold less potent than bupropion. This may be of clinical importance because the plasma concentrations of the metabolites are as high as or higher than those of bupropion. Bupropion and its metabolites exhibit linear kinetics following chronic administration of 300 to 450 mg per day. •Metabolism (Drug B): Morphine is 90% metabolized by glucuronidation by UGT2B7 and sulfation at positions 3 and 6. Morphine can also be metabolized to codeine, normorphine, and morphine ethereal sulfate. •Route of elimination (Drug A): Bupropion is extensively metabolized in humans. Oxidation of the bupropion side chain results in the formation of a glycine conjugate of metachlorobenzoic acid, which is then excreted as the major urinary metabolite. Following oral administration of 200 mg of 14C-bupropion in humans, 87% and 10% of the radioactive dose were recovered in the urine and feces, respectively. However, the fraction of the oral dose of bupropion excreted unchanged was only 0.5%, a finding consistent with the extensive metabolism of bupropion. •Route of elimination (Drug B): 70-80% of an administered dose is excreted within 48 hours. Morphine is predominantly eliminated in the urine with 2-10% of a dose recovered as the unchanged parent drug. 7-10% of a dose of morphine is eliminated in the feces. •Half-life (Drug A): 24 hours •Half-life (Drug B): Morphine has a half life of 2-3 hours. •Clearance (Drug A): No clearance available •Clearance (Drug B): The apparent clearance of intravenous or subcutaneous morphine is 1600 mL/min. •Toxicity (Drug A): Symptoms of overdose include seizures, hallucinations, loss of consciousness, tachycardia, and cardiac arrest. •Toxicity (Drug B): The LD 50 is 0.78µg/mL in males and 0.98µg/mL in females. Patients experiencing an overdose present with respiratory depression, somnolence, skeletal muscle flaccidity, cold and clammy skin, miosis, and mydriasis. Symptoms of overdose can progress to pulmonary edema, bradycardia, hypotension, cardiac arrest, and death. Treat overdose with symptomatic and supportive treatment which may include the use of oxygen, vasopressors, and naloxone. •Brand Names (Drug A): Aplenzin, Auvelity, Budeprion, Contrave, Forfivo, Wellbutrin, Zyban •Brand Names (Drug B): Arymo, Avinza, Doloral, Duramorph, Embeda, Infumorph, Kadian, M-ediat, M-eslon, MSIR, Mitigo, Ms Contin, Statex •Synonyms (Drug A): No synonyms listed •Synonyms (Drug B): Morfina Morphia Morphin Morphine Morphinum Morphium •Summary (Drug A): Bupropion is a norepinephrine and dopamine reuptake inhibitor used in the treatment of major depressive disorder (MDD), seasonal affective disorder (SAD), and as an aid to smoking cessation. •Summary (Drug B): Morphine is an opioid agonist used for the relief of moderate to severe acute and chronic pain. Output: Central nervous system (CNS) depressants can cause sedation, falls, respiratory depression, coma, and death.2,3 The potential interaction between a CNS depressant and another CNS depressant drug due to synergistic effects is well documented in the literature, although the risk and severity of CNS depression vary from each drug. The subject and affected drugs are both CNS depressants that, when co-administered, may result in a more profound CNS depression. As the risk and severity of CNS depression resulting from the combined use of CNS depressants vary from each agent, each interaction between CNS depressants should be considered individually. The severity of the interaction is moderate.

Does Bupropion and Mycophenolate mofetil interact?

•Drug A: Bupropion •Drug B: Mycophenolate mofetil •Severity: MINOR •Description: Mycophenolate mofetil may decrease the excretion rate of Bupropion which could result in a higher serum level. •Extended Description: The renal excretion of drugs is the overall result of a combination of kidney processes that include glomerular filtration, passive diffusion, tubular secretion, and tubular reabsorption. Since two of these mechanisms - tubular secretion and reabsorption - are saturable processes , they are consequently susceptible to competition between multiple substrates excreted by the kidneys. If two or more medications that are mainly renally excreted are co-administered, they may compete for renal elimination; there is a large likelihood that one agent may "out-compete" or saturate the renal excretion mechanisms before the other concomitantly administered agent(s) are excreted. As a result, the elimination of these other concurrently administered agents may be inhibited or otherwise delayed, which could lead to increases in their serum concentrations and the risk, incidence, and/or severity of adverse effects associated with the exposure to such drugs. •Indication (Drug A): Bupropion is indicated for the treatment of major depressive disorder (MDD), seasonal affective disorder (SAD), and as an aid to smoking cessation. When used in combination with naltrexone as the marketed product ContraveⓇ, bupropion is indicated as an adjunct to a reduced-calorie diet and increased physical activity for chronic weight management in adults with an initial body mass index (BMI) of: 30 kg/m^2 or greater (obese) or 27 kg/m^2 or greater (overweight) in the presence of at least one weight-related comorbid condition (e.g., hypertension, type 2 diabetes mellitus, or dyslipidemia). Bupropion is also used off-label as a first-line treatment in patients with ADHD and comorbid bipolar disorder when used as an adjunct to mood stabilizers. •Indication (Drug B): Mycophenolate mofetil is indicated in combination with other immunosuppressants to prevent the rejection of kidney, heart, or liver transplants in adult and pediatric patients ≥3 months old. Mycophenolate mofetil may also be used off-label as a second-line treatment for autoimmune hepatitis that has not responded adequately to first-line therapy. Other off-label uses of this drug include lupus-associated nephritis and dermatitis in children. •Pharmacodynamics (Drug A): Bupropion is chemically unrelated to tricyclic, tetracyclic, selective serotonin re-uptake inhibitors, or other known antidepressant agents. Compared to classical tricyclic antidepressants, Bupropion is a relatively weak inhibitor of the neuronal uptake of norepinephrine and dopamine. In addition, Bupropion does not inhibit monoamine oxidase. Bupropion has been found to be essentially inactive at the serotonin transporter (SERT)(IC50 >10 000 nM), however both bupropion and its primary metabolite hydroxybupropion have been found to block the function of cation-selective serotonin type 3A receptors (5-HT3ARs). Bupropion produces dose-related central nervous system (CNS) stimulant effects in animals, as evidenced by increased locomotor activity, increased rates of responding in various schedule-controlled operant behaviour tasks, and, at high doses, induction of mild stereotyped behaviour. Due to these stimulant effects and selective activity at dopamine and norepinephrine receptors, bupropion has been identified as having an abuse potential. Bupropion has a similar structure to the controlled substance Cathinone, and has been identified as having mild amphetamine-like activity, particularly when inhaled or injected. Bupropion is also known to lower the seizure threshold, making any pre-existing seizure conditions a contraindication to its use. This risk is exacerbated when bupropion is combined with other drugs or substances that lower the seizure threshold, such as cocaine, or in clinical situations that would increase the risk of a seizure such as abrupt alcohol or benzodiazepine withdrawal. As norepinephrine has been shown to have anticonvulsant properties, bupropion's inhibitory effects on NET are thought to contribute to its pro-convulsant activity. Bupropion has been shown to increase blood pressure and pose a risk for exacerbation of unmanaged or pre-existing hypertension, however, clinical trials of bupropion in smokers with CVD have not identified an increased incidence of CV events including stroke or heart attack. In clinical trials, the mean increase in systolic blood pressure associated with the use of bupropion was found to be 1.3 mmHg. •Pharmacodynamics (Drug B): Mycophenolate mofetil is a prodrug of mycophenolic acid (MPA). The active form of mycophenolate, MPA, prevents the proliferation of immune cells and the formation of antibodies that cause transplant rejection. The above effects lead to higher rates of successful transplantation, avoiding the devastating effects of graft rejection. •Mechanism of action (Drug A): Bupropion is a norepinephrine/dopamine-reuptake inhibitor (NDRI) that exerts its pharmacological effects by weakly inhibiting the enzymes involved in the uptake of the neurotransmitters norepinephrine and dopamine from the synaptic cleft, therefore prolonging their duration of action within the neuronal synapse and the downstream effects of these neurotransmitters. More specifically, bupropion binds to the norepinephrine transporter (NET) and the dopamine transporter (DAT). Bupropion was originally classified as an "atypical" antidepressant because it does not exert the same effects as the classical antidepressants such as Monoamine Oxidase Inhibitors (MAOIs), Tricyclic Antidepressants (TCAs), or Selective Serotonin Reuptake Inhibitors (SSRIs). While it has comparable effectiveness to typical first-line options for the treatment of depression such as SSRIs, bupropion is a unique option for the treatment of MDD as it lacks any clinically relevant serotonergic effects, typical of other mood medications, or any effects on histamine or adrenaline receptors. Lack of activity at these receptors results in a more tolerable side effect profile; bupropion is less likely to cause sexual side effects, sedation, or weight gain as compared to SSRIs or TCAs, for example. When used as an aid to smoking cessation, bupropion is thought to confer its anti-craving and anti-withdrawal effects by inhibiting dopamine reuptake, which is thought to be involved in the reward pathways associated with nicotine, and through the antagonism of the nicotinic acetylcholinergic receptor (AChR), thereby blunting the effects of nicotine. Furthermore, the stimulatory effects produced by bupropion in the central nervous system are similar to nicotine's effects, making low doses of bupropion a suitable option as a nicotine substitute. When used in combination with naltrexone in the marketed product ContraveⓇ for chronic weight management, the two components are thought to have effects on areas of the brain involved in the regulation of food intake. This includes the hypothalamus, which is involved in appetite regulation, and the mesolimbic dopamine circuit, which is involved in reward pathways. Studies have shown that the combined activity of bupropion and naltrexone increase the firing rate of hypothalamic pro-opiomelanocortin (POMC) neurons and blockade of opioid receptor-mediated POMC auto-inhibition, which are associated with a reduction in food intake and increased energy expenditure. This combination was also found to reduce food intake when injected directly into the ventral tegmental area of the mesolimbic circuit in mice, which is an area associated with the regulation of reward pathways. •Mechanism of action (Drug B): The active metabolite of mycophenolate, mycophenolic acid, prevents T-cell and B-cell proliferation and the production of cytotoxic T-cells and antibodies. Lymphocyte and monocyte adhesion to endothelial cells of blood vessels that normally part of inflammation is prevented via the glycosylation of cell adhesion molecules by MPA. MPA inhibits de novo purine biosynthesis (that promotes immune cell proliferation) by inhibiting inosine 5’-monophosphate dehydrogenase enzyme (IMPDH), with a preferential inhibition of IMPDH II. IMPDH normally transforms inosine monophosphate (IMP) to xanthine monophosphate (XMP), a metabolite contributing to the production of guanosine triphosphate (GTP). GTP is an important molecule for the synthesis of ribonucleic acid (RNA), deoxyribonucleic acid (DNA), and protein. As a result of the above cascade of effects, mycophenolate mofetil reduces de-novo production of guanosine nucleotides, interfering with the synthesis of DNA, RNA, and protein required for immune cell production. Further contributing to the above anti-inflammatory effects, MMF depletes tetrahydrobiopterin, causing the decreased function of inducible nitric oxide synthase enzyme, in turn decreasing the production of peroxynitrite, a molecule that promotes inflammation. •Absorption (Drug A): Bupropion is currently available in 3 distinct, but bioequivalent formulations: immediate release (IR), sustained-release (SR), and extended-release (XL). Immediate Release Formulation In humans, following oral administration of bupropion hydrochloride tablets, peak plasma bupropion concentrations are usually achieved within 2 hours. IR formulations provide a short duration of action and are therefore generally dosed three times per day. Sustained Release Formulation In humans, following oral administration of bupropion hydrochloride sustained-release tablets (SR), peak plasma concentration (Cmax) of bupropion is usually achieved within 3 hours. SR formulations provide a 12-hour extended release of medication and are therefore generally dosed twice per day. Extended Release Formulation Following single oral administration of bupropion hydrochloride extended-release tablets (XL) to healthy volunteers, the median time to peak plasma concentrations for bupropion was approximately 5 hours. The presence of food did not affect the peak concentration or area under the curve of bupropion. XL formulations provide a 24-hour extended release of medication and are therefore generally dosed once per day/ In a trial comparing chronic dosing with bupropion hydrochloride extended-release tablets (SR) 150 mg twice daily to bupropion immediate-release formulation 100 mg 3 times daily, the steady state Cmax for bupropion after bupropion hydrochloride sustained-release tablets (SR) administration was approximately 85% of those achieved after bupropion immediate-release formulation administration. Exposure (AUC) to bupropion was equivalent for both formulations. Bioequivalence was also demonstrated for all three major active metabolites (i.e., hydroxybupropion, threohydrobupropion and erythrohydrobupropion) for both Cmax and AUC. Thus, at steady state, bupropion hydrochloride sustained-release tablets (SR) given twice daily, and the immediate-release formulation of bupropion given 3 times daily, are essentially bioequivalent for both bupropion and the 3 quantitatively important metabolites. Furthermore, in a study comparing 14-day dosing with bupropion hydrochloride extended-release tablets (XL), 300 mg once-daily to the immediate-release formulation of bupropion at 100 mg 3 times daily, equivalence was demonstrated for peak plasma concentration and area under the curve for bupropion and the three metabolites (hydroxybupropion, threohydrobupropion, and erythrohydrobupropion). Additionally, in a study comparing 14-day dosing with bupropion hydrochloride extended-release tablets (XL) 300 mg once daily to the sustained-release formulation of bupropion at 150 mg 2 times daily, equivalence was demonstrated for peak plasma concentration and area under the curve for bupropion and the three metabolites. Bupropion hydrochloride extended-release tablets (SR) can be taken with or without food. Bupropion Cmax and AUC were increased by 11% to 35% and 16% to 19%, respectively, when bupropion hydrochloride extended-release tablets (SR) was administered with food to healthy volunteers in three trials. The food effect is not considered clinically significant. Following a single-dose administration of bupropion hydrochloride extended-release tablets (SR) in humans, Cmax of bupropion's metabolite hydroxybupropion occurs approximately 6 hours post-dose and is approximately 10 times the peak level of the parent drug at steady state. The elimination half-life of hydroxybupropion is approximately 20 (±5) hours and its AUC at steady state is about 17 times that of bupropion. The times to peak concentrations for the erythrohydrobupropion and threohydrobupropion metabolites are similar to that of the hydroxybupropion metabolite. However, their elimination half-lives are longer, 33(±10) and 37 (±13) hours, respectively, and steady-state AUCs are 1.5 and 7 times that of bupropion, respectively. •Absorption (Drug B): Mycophenolate mofetil is rapidly absorbed in the small intestine. The maximum concentration of its active metabolite, MPA, is attained 60 to 90 minutes following an oral dose. The average bioavailability of orally administered mycophenolate mofetil in a pharmacokinetic study of 12 healthy patients was 94%. In healthy volunteers, the Cmax of mycophenolate mofetil was 24.5 (±9.5)μg/mL. In renal transplant patients 5 days post-transplant, Cmax was 12.0 (±3.82) μg/mL, increasing to 24.1 (±12.1)μg/mL 3 months after transplantation. AUC values were 63.9 (±16.2) μg•h/mL in healthy volunteers after one dose, and 40.8 (±11.4) μg•h/mL, and 65.3 (±35.4)μg•h/mL 5 days and 3 months after a renal transplant, respectively. The absorption of mycophenolate mofetil is not affected by food. •Volume of distribution (Drug A): No volume of distribution available •Volume of distribution (Drug B): The volume of distribution of mycophenolate mofetil is 3.6 (±1.5) to 4.0 (±1.2) L/kg. •Protein binding (Drug A): In vitro tests show that bupropion is 84% bound to human plasma proteins at concentrations up to 200 mcg per mL. The extent of protein binding of the hydroxybupropion metabolite is similar to that for bupropion, whereas the extent of protein binding of the threohydrobupropion metabolite is about half that seen with bupropion. •Protein binding (Drug B): The protein binding of mycophenolic acid, the metabolite of mycophenolate mofetil, is 97% and it is mainly bound to albumin. MPAG, the inactive metabolite, is 82% bound to plasma albumin at normal therapeutic concentrations. At elevated MPAG concentrations due to various reasons, including renal impairment, the binding of MPA may be decreased due to competition for binding. •Metabolism (Drug A): Bupropion is extensively metabolized in humans. Three metabolites are active: hydroxybupropion, which is formed via hydroxylation of the tert-butyl group of bupropion, and the amino-alcohol isomers, threohydrobupropion and erythrohydrobupropion, which are formed via reduction of the carbonyl group. In vitro findings suggest that CYP2B6 is the principal isoenzyme involved in the formation of hydroxybupropion, while cytochrome P450 enzymes are not involved in the formation of threohydrobupropion. Hydroxybupropion has been shown to have the same affinity as bupropion for the norepinephrine transporter (NET) but approximately 50% of its antidepressant activity despite reaching concentrations of ~10-fold higher than that of the parent drug. Oxidation of the bupropion side chain results in the formation of a glycine conjugate of meta-chlorobenzoic acid, which is then excreted as the major urinary metabolite. The potency and toxicity of the metabolites relative to bupropion have not been fully characterized. However, it has been demonstrated in an antidepressant screening test in mice that hydroxybupropion is one-half as potent as bupropion, while threohydrobupropion and erythrohydrobupropion are 5-fold less potent than bupropion. This may be of clinical importance because the plasma concentrations of the metabolites are as high as or higher than those of bupropion. Bupropion and its metabolites exhibit linear kinetics following chronic administration of 300 to 450 mg per day. •Metabolism (Drug B): After both oral and intravenous administration mycophenolate mofetil is entirely metabolized by liver carboxylesterases 1 and 2 to mycophenolic acid (MPA), the active parent drug. It is then metabolized by the enzyme glucuronyl transferase, producing the inactive phenolic glucuronide of MPA (MPAG). The glucuronide metabolite is important, as it is then converted to MPA through enterohepatic recirculation. Mycophenolate mofetil that escapes metabolism in the intestine enters the liver via the portal vein and is transformed to pharmacologically active MPA in the liver cells. N-(2-carboxymethyl)-morpholine, N-(2-hydroxyethyl)-morpholine, and the N-oxide portion of N-(2-hydroxyethyl)-morpholine are additional metabolites of MMF occurring in the intestine as a result of liver carboxylesterase 2 activity. UGT1A9 and UGT2B7 in the liver are the major enzymes contributing to the metabolism of MPA in addition to other UGT enzymes, which also play a role in MPA metabolism. The four major metabolites of MPA are 7-O-MPA-β-glucuronide (MPAG, inactive), MPA acyl-glucuronide (AcMPAG), produced by uridine 5ʹ-diphosphate glucuronosyltransferases (UGT) activities, 7-O-MPA glucoside produced via UGT, and small amounts 6-O-des-methyl-MPA (DM-MPA) via CYP3A4/5 and CYP2C8 enzymes. •Route of elimination (Drug A): Bupropion is extensively metabolized in humans. Oxidation of the bupropion side chain results in the formation of a glycine conjugate of metachlorobenzoic acid, which is then excreted as the major urinary metabolite. Following oral administration of 200 mg of 14C-bupropion in humans, 87% and 10% of the radioactive dose were recovered in the urine and feces, respectively. However, the fraction of the oral dose of bupropion excreted unchanged was only 0.5%, a finding consistent with the extensive metabolism of bupropion. •Route of elimination (Drug B): A small amount of drug is excreted as MPA in the urine (less than 1%). When mycophenolate mofetil was given orally in a pharmacokinetic study, it was found to be 93% excreted in urine and 6% excreted in feces. Approximately 87% of the entire administered dose is found to be excreted in the urine as MPAG, an inactive metabolite. •Half-life (Drug A): 24 hours •Half-life (Drug B): The average apparent half-life of mycophenolate mofetil is 17.9 (±6.5) hours after oral administration and 16.6 (±5.8) hours after intravenous administration. •Clearance (Drug A): No clearance available •Clearance (Drug B): Plasma clearance of mycophenolate mofetil is 193 mL/min after an oral dose and 177 (±31) mL/min after an intravenous dose. •Toxicity (Drug A): Symptoms of overdose include seizures, hallucinations, loss of consciousness, tachycardia, and cardiac arrest. •Toxicity (Drug B): LD50 The LD50 of oral mycophenolate mofetil in rats is 250 mg/kg and >4000 mg/kg in mice. Overdose information Possible signs and symptoms of acute overdose may consist of hematological abnormalities including leukopenia and neutropenia, and gastrointestinal symptoms. •Brand Names (Drug A): Aplenzin, Auvelity, Budeprion, Contrave, Forfivo, Wellbutrin, Zyban •Brand Names (Drug B): Cellcept, Myfenax •Synonyms (Drug A): No synonyms listed •Synonyms (Drug B): Mycophenolate mofetil Mycophenolic acid morpholinoethyl ester •Summary (Drug A): Bupropion is a norepinephrine and dopamine reuptake inhibitor used in the treatment of major depressive disorder (MDD), seasonal affective disorder (SAD), and as an aid to smoking cessation. •Summary (Drug B): Mycophenolate mofetil is an inosine monophosphate dehydrogenase inhibitor used to prevent the rejection of kidney, heart, or liver transplants.

The renal excretion of drugs is the overall result of a combination of kidney processes that include glomerular filtration, passive diffusion, tubular secretion, and tubular reabsorption. Since two of these mechanisms - tubular secretion and reabsorption - are saturable processes , they are consequently susceptible to competition between multiple substrates excreted by the kidneys. If two or more medications that are mainly renally excreted are co-administered, they may compete for renal elimination; there is a large likelihood that one agent may "out-compete" or saturate the renal excretion mechanisms before the other concomitantly administered agent(s) are excreted. As a result, the elimination of these other concurrently administered agents may be inhibited or otherwise delayed, which could lead to increases in their serum concentrations and the risk, incidence, and/or severity of adverse effects associated with the exposure to such drugs. The severity of the interaction is minor.

Question: Does Bupropion and Mycophenolate mofetil interact? Information: •Drug A: Bupropion •Drug B: Mycophenolate mofetil •Severity: MINOR •Description: Mycophenolate mofetil may decrease the excretion rate of Bupropion which could result in a higher serum level. •Extended Description: The renal excretion of drugs is the overall result of a combination of kidney processes that include glomerular filtration, passive diffusion, tubular secretion, and tubular reabsorption. Since two of these mechanisms - tubular secretion and reabsorption - are saturable processes , they are consequently susceptible to competition between multiple substrates excreted by the kidneys. If two or more medications that are mainly renally excreted are co-administered, they may compete for renal elimination; there is a large likelihood that one agent may "out-compete" or saturate the renal excretion mechanisms before the other concomitantly administered agent(s) are excreted. As a result, the elimination of these other concurrently administered agents may be inhibited or otherwise delayed, which could lead to increases in their serum concentrations and the risk, incidence, and/or severity of adverse effects associated with the exposure to such drugs. •Indication (Drug A): Bupropion is indicated for the treatment of major depressive disorder (MDD), seasonal affective disorder (SAD), and as an aid to smoking cessation. When used in combination with naltrexone as the marketed product ContraveⓇ, bupropion is indicated as an adjunct to a reduced-calorie diet and increased physical activity for chronic weight management in adults with an initial body mass index (BMI) of: 30 kg/m^2 or greater (obese) or 27 kg/m^2 or greater (overweight) in the presence of at least one weight-related comorbid condition (e.g., hypertension, type 2 diabetes mellitus, or dyslipidemia). Bupropion is also used off-label as a first-line treatment in patients with ADHD and comorbid bipolar disorder when used as an adjunct to mood stabilizers. •Indication (Drug B): Mycophenolate mofetil is indicated in combination with other immunosuppressants to prevent the rejection of kidney, heart, or liver transplants in adult and pediatric patients ≥3 months old. Mycophenolate mofetil may also be used off-label as a second-line treatment for autoimmune hepatitis that has not responded adequately to first-line therapy. Other off-label uses of this drug include lupus-associated nephritis and dermatitis in children. •Pharmacodynamics (Drug A): Bupropion is chemically unrelated to tricyclic, tetracyclic, selective serotonin re-uptake inhibitors, or other known antidepressant agents. Compared to classical tricyclic antidepressants, Bupropion is a relatively weak inhibitor of the neuronal uptake of norepinephrine and dopamine. In addition, Bupropion does not inhibit monoamine oxidase. Bupropion has been found to be essentially inactive at the serotonin transporter (SERT)(IC50 >10 000 nM), however both bupropion and its primary metabolite hydroxybupropion have been found to block the function of cation-selective serotonin type 3A receptors (5-HT3ARs). Bupropion produces dose-related central nervous system (CNS) stimulant effects in animals, as evidenced by increased locomotor activity, increased rates of responding in various schedule-controlled operant behaviour tasks, and, at high doses, induction of mild stereotyped behaviour. Due to these stimulant effects and selective activity at dopamine and norepinephrine receptors, bupropion has been identified as having an abuse potential. Bupropion has a similar structure to the controlled substance Cathinone, and has been identified as having mild amphetamine-like activity, particularly when inhaled or injected. Bupropion is also known to lower the seizure threshold, making any pre-existing seizure conditions a contraindication to its use. This risk is exacerbated when bupropion is combined with other drugs or substances that lower the seizure threshold, such as cocaine, or in clinical situations that would increase the risk of a seizure such as abrupt alcohol or benzodiazepine withdrawal. As norepinephrine has been shown to have anticonvulsant properties, bupropion's inhibitory effects on NET are thought to contribute to its pro-convulsant activity. Bupropion has been shown to increase blood pressure and pose a risk for exacerbation of unmanaged or pre-existing hypertension, however, clinical trials of bupropion in smokers with CVD have not identified an increased incidence of CV events including stroke or heart attack. In clinical trials, the mean increase in systolic blood pressure associated with the use of bupropion was found to be 1.3 mmHg. •Pharmacodynamics (Drug B): Mycophenolate mofetil is a prodrug of mycophenolic acid (MPA). The active form of mycophenolate, MPA, prevents the proliferation of immune cells and the formation of antibodies that cause transplant rejection. The above effects lead to higher rates of successful transplantation, avoiding the devastating effects of graft rejection. •Mechanism of action (Drug A): Bupropion is a norepinephrine/dopamine-reuptake inhibitor (NDRI) that exerts its pharmacological effects by weakly inhibiting the enzymes involved in the uptake of the neurotransmitters norepinephrine and dopamine from the synaptic cleft, therefore prolonging their duration of action within the neuronal synapse and the downstream effects of these neurotransmitters. More specifically, bupropion binds to the norepinephrine transporter (NET) and the dopamine transporter (DAT). Bupropion was originally classified as an "atypical" antidepressant because it does not exert the same effects as the classical antidepressants such as Monoamine Oxidase Inhibitors (MAOIs), Tricyclic Antidepressants (TCAs), or Selective Serotonin Reuptake Inhibitors (SSRIs). While it has comparable effectiveness to typical first-line options for the treatment of depression such as SSRIs, bupropion is a unique option for the treatment of MDD as it lacks any clinically relevant serotonergic effects, typical of other mood medications, or any effects on histamine or adrenaline receptors. Lack of activity at these receptors results in a more tolerable side effect profile; bupropion is less likely to cause sexual side effects, sedation, or weight gain as compared to SSRIs or TCAs, for example. When used as an aid to smoking cessation, bupropion is thought to confer its anti-craving and anti-withdrawal effects by inhibiting dopamine reuptake, which is thought to be involved in the reward pathways associated with nicotine, and through the antagonism of the nicotinic acetylcholinergic receptor (AChR), thereby blunting the effects of nicotine. Furthermore, the stimulatory effects produced by bupropion in the central nervous system are similar to nicotine's effects, making low doses of bupropion a suitable option as a nicotine substitute. When used in combination with naltrexone in the marketed product ContraveⓇ for chronic weight management, the two components are thought to have effects on areas of the brain involved in the regulation of food intake. This includes the hypothalamus, which is involved in appetite regulation, and the mesolimbic dopamine circuit, which is involved in reward pathways. Studies have shown that the combined activity of bupropion and naltrexone increase the firing rate of hypothalamic pro-opiomelanocortin (POMC) neurons and blockade of opioid receptor-mediated POMC auto-inhibition, which are associated with a reduction in food intake and increased energy expenditure. This combination was also found to reduce food intake when injected directly into the ventral tegmental area of the mesolimbic circuit in mice, which is an area associated with the regulation of reward pathways. •Mechanism of action (Drug B): The active metabolite of mycophenolate, mycophenolic acid, prevents T-cell and B-cell proliferation and the production of cytotoxic T-cells and antibodies. Lymphocyte and monocyte adhesion to endothelial cells of blood vessels that normally part of inflammation is prevented via the glycosylation of cell adhesion molecules by MPA. MPA inhibits de novo purine biosynthesis (that promotes immune cell proliferation) by inhibiting inosine 5’-monophosphate dehydrogenase enzyme (IMPDH), with a preferential inhibition of IMPDH II. IMPDH normally transforms inosine monophosphate (IMP) to xanthine monophosphate (XMP), a metabolite contributing to the production of guanosine triphosphate (GTP). GTP is an important molecule for the synthesis of ribonucleic acid (RNA), deoxyribonucleic acid (DNA), and protein. As a result of the above cascade of effects, mycophenolate mofetil reduces de-novo production of guanosine nucleotides, interfering with the synthesis of DNA, RNA, and protein required for immune cell production. Further contributing to the above anti-inflammatory effects, MMF depletes tetrahydrobiopterin, causing the decreased function of inducible nitric oxide synthase enzyme, in turn decreasing the production of peroxynitrite, a molecule that promotes inflammation. •Absorption (Drug A): Bupropion is currently available in 3 distinct, but bioequivalent formulations: immediate release (IR), sustained-release (SR), and extended-release (XL). Immediate Release Formulation In humans, following oral administration of bupropion hydrochloride tablets, peak plasma bupropion concentrations are usually achieved within 2 hours. IR formulations provide a short duration of action and are therefore generally dosed three times per day. Sustained Release Formulation In humans, following oral administration of bupropion hydrochloride sustained-release tablets (SR), peak plasma concentration (Cmax) of bupropion is usually achieved within 3 hours. SR formulations provide a 12-hour extended release of medication and are therefore generally dosed twice per day. Extended Release Formulation Following single oral administration of bupropion hydrochloride extended-release tablets (XL) to healthy volunteers, the median time to peak plasma concentrations for bupropion was approximately 5 hours. The presence of food did not affect the peak concentration or area under the curve of bupropion. XL formulations provide a 24-hour extended release of medication and are therefore generally dosed once per day/ In a trial comparing chronic dosing with bupropion hydrochloride extended-release tablets (SR) 150 mg twice daily to bupropion immediate-release formulation 100 mg 3 times daily, the steady state Cmax for bupropion after bupropion hydrochloride sustained-release tablets (SR) administration was approximately 85% of those achieved after bupropion immediate-release formulation administration. Exposure (AUC) to bupropion was equivalent for both formulations. Bioequivalence was also demonstrated for all three major active metabolites (i.e., hydroxybupropion, threohydrobupropion and erythrohydrobupropion) for both Cmax and AUC. Thus, at steady state, bupropion hydrochloride sustained-release tablets (SR) given twice daily, and the immediate-release formulation of bupropion given 3 times daily, are essentially bioequivalent for both bupropion and the 3 quantitatively important metabolites. Furthermore, in a study comparing 14-day dosing with bupropion hydrochloride extended-release tablets (XL), 300 mg once-daily to the immediate-release formulation of bupropion at 100 mg 3 times daily, equivalence was demonstrated for peak plasma concentration and area under the curve for bupropion and the three metabolites (hydroxybupropion, threohydrobupropion, and erythrohydrobupropion). Additionally, in a study comparing 14-day dosing with bupropion hydrochloride extended-release tablets (XL) 300 mg once daily to the sustained-release formulation of bupropion at 150 mg 2 times daily, equivalence was demonstrated for peak plasma concentration and area under the curve for bupropion and the three metabolites. Bupropion hydrochloride extended-release tablets (SR) can be taken with or without food. Bupropion Cmax and AUC were increased by 11% to 35% and 16% to 19%, respectively, when bupropion hydrochloride extended-release tablets (SR) was administered with food to healthy volunteers in three trials. The food effect is not considered clinically significant. Following a single-dose administration of bupropion hydrochloride extended-release tablets (SR) in humans, Cmax of bupropion's metabolite hydroxybupropion occurs approximately 6 hours post-dose and is approximately 10 times the peak level of the parent drug at steady state. The elimination half-life of hydroxybupropion is approximately 20 (±5) hours and its AUC at steady state is about 17 times that of bupropion. The times to peak concentrations for the erythrohydrobupropion and threohydrobupropion metabolites are similar to that of the hydroxybupropion metabolite. However, their elimination half-lives are longer, 33(±10) and 37 (±13) hours, respectively, and steady-state AUCs are 1.5 and 7 times that of bupropion, respectively. •Absorption (Drug B): Mycophenolate mofetil is rapidly absorbed in the small intestine. The maximum concentration of its active metabolite, MPA, is attained 60 to 90 minutes following an oral dose. The average bioavailability of orally administered mycophenolate mofetil in a pharmacokinetic study of 12 healthy patients was 94%. In healthy volunteers, the Cmax of mycophenolate mofetil was 24.5 (±9.5)μg/mL. In renal transplant patients 5 days post-transplant, Cmax was 12.0 (±3.82) μg/mL, increasing to 24.1 (±12.1)μg/mL 3 months after transplantation. AUC values were 63.9 (±16.2) μg•h/mL in healthy volunteers after one dose, and 40.8 (±11.4) μg•h/mL, and 65.3 (±35.4)μg•h/mL 5 days and 3 months after a renal transplant, respectively. The absorption of mycophenolate mofetil is not affected by food. •Volume of distribution (Drug A): No volume of distribution available •Volume of distribution (Drug B): The volume of distribution of mycophenolate mofetil is 3.6 (±1.5) to 4.0 (±1.2) L/kg. •Protein binding (Drug A): In vitro tests show that bupropion is 84% bound to human plasma proteins at concentrations up to 200 mcg per mL. The extent of protein binding of the hydroxybupropion metabolite is similar to that for bupropion, whereas the extent of protein binding of the threohydrobupropion metabolite is about half that seen with bupropion. •Protein binding (Drug B): The protein binding of mycophenolic acid, the metabolite of mycophenolate mofetil, is 97% and it is mainly bound to albumin. MPAG, the inactive metabolite, is 82% bound to plasma albumin at normal therapeutic concentrations. At elevated MPAG concentrations due to various reasons, including renal impairment, the binding of MPA may be decreased due to competition for binding. •Metabolism (Drug A): Bupropion is extensively metabolized in humans. Three metabolites are active: hydroxybupropion, which is formed via hydroxylation of the tert-butyl group of bupropion, and the amino-alcohol isomers, threohydrobupropion and erythrohydrobupropion, which are formed via reduction of the carbonyl group. In vitro findings suggest that CYP2B6 is the principal isoenzyme involved in the formation of hydroxybupropion, while cytochrome P450 enzymes are not involved in the formation of threohydrobupropion. Hydroxybupropion has been shown to have the same affinity as bupropion for the norepinephrine transporter (NET) but approximately 50% of its antidepressant activity despite reaching concentrations of ~10-fold higher than that of the parent drug. Oxidation of the bupropion side chain results in the formation of a glycine conjugate of meta-chlorobenzoic acid, which is then excreted as the major urinary metabolite. The potency and toxicity of the metabolites relative to bupropion have not been fully characterized. However, it has been demonstrated in an antidepressant screening test in mice that hydroxybupropion is one-half as potent as bupropion, while threohydrobupropion and erythrohydrobupropion are 5-fold less potent than bupropion. This may be of clinical importance because the plasma concentrations of the metabolites are as high as or higher than those of bupropion. Bupropion and its metabolites exhibit linear kinetics following chronic administration of 300 to 450 mg per day. •Metabolism (Drug B): After both oral and intravenous administration mycophenolate mofetil is entirely metabolized by liver carboxylesterases 1 and 2 to mycophenolic acid (MPA), the active parent drug. It is then metabolized by the enzyme glucuronyl transferase, producing the inactive phenolic glucuronide of MPA (MPAG). The glucuronide metabolite is important, as it is then converted to MPA through enterohepatic recirculation. Mycophenolate mofetil that escapes metabolism in the intestine enters the liver via the portal vein and is transformed to pharmacologically active MPA in the liver cells. N-(2-carboxymethyl)-morpholine, N-(2-hydroxyethyl)-morpholine, and the N-oxide portion of N-(2-hydroxyethyl)-morpholine are additional metabolites of MMF occurring in the intestine as a result of liver carboxylesterase 2 activity. UGT1A9 and UGT2B7 in the liver are the major enzymes contributing to the metabolism of MPA in addition to other UGT enzymes, which also play a role in MPA metabolism. The four major metabolites of MPA are 7-O-MPA-β-glucuronide (MPAG, inactive), MPA acyl-glucuronide (AcMPAG), produced by uridine 5ʹ-diphosphate glucuronosyltransferases (UGT) activities, 7-O-MPA glucoside produced via UGT, and small amounts 6-O-des-methyl-MPA (DM-MPA) via CYP3A4/5 and CYP2C8 enzymes. •Route of elimination (Drug A): Bupropion is extensively metabolized in humans. Oxidation of the bupropion side chain results in the formation of a glycine conjugate of metachlorobenzoic acid, which is then excreted as the major urinary metabolite. Following oral administration of 200 mg of 14C-bupropion in humans, 87% and 10% of the radioactive dose were recovered in the urine and feces, respectively. However, the fraction of the oral dose of bupropion excreted unchanged was only 0.5%, a finding consistent with the extensive metabolism of bupropion. •Route of elimination (Drug B): A small amount of drug is excreted as MPA in the urine (less than 1%). When mycophenolate mofetil was given orally in a pharmacokinetic study, it was found to be 93% excreted in urine and 6% excreted in feces. Approximately 87% of the entire administered dose is found to be excreted in the urine as MPAG, an inactive metabolite. •Half-life (Drug A): 24 hours •Half-life (Drug B): The average apparent half-life of mycophenolate mofetil is 17.9 (±6.5) hours after oral administration and 16.6 (±5.8) hours after intravenous administration. •Clearance (Drug A): No clearance available •Clearance (Drug B): Plasma clearance of mycophenolate mofetil is 193 mL/min after an oral dose and 177 (±31) mL/min after an intravenous dose. •Toxicity (Drug A): Symptoms of overdose include seizures, hallucinations, loss of consciousness, tachycardia, and cardiac arrest. •Toxicity (Drug B): LD50 The LD50 of oral mycophenolate mofetil in rats is 250 mg/kg and >4000 mg/kg in mice. Overdose information Possible signs and symptoms of acute overdose may consist of hematological abnormalities including leukopenia and neutropenia, and gastrointestinal symptoms. •Brand Names (Drug A): Aplenzin, Auvelity, Budeprion, Contrave, Forfivo, Wellbutrin, Zyban •Brand Names (Drug B): Cellcept, Myfenax •Synonyms (Drug A): No synonyms listed •Synonyms (Drug B): Mycophenolate mofetil Mycophenolic acid morpholinoethyl ester •Summary (Drug A): Bupropion is a norepinephrine and dopamine reuptake inhibitor used in the treatment of major depressive disorder (MDD), seasonal affective disorder (SAD), and as an aid to smoking cessation. •Summary (Drug B): Mycophenolate mofetil is an inosine monophosphate dehydrogenase inhibitor used to prevent the rejection of kidney, heart, or liver transplants. Output: The renal excretion of drugs is the overall result of a combination of kidney processes that include glomerular filtration, passive diffusion, tubular secretion, and tubular reabsorption. Since two of these mechanisms - tubular secretion and reabsorption - are saturable processes , they are consequently susceptible to competition between multiple substrates excreted by the kidneys. If two or more medications that are mainly renally excreted are co-administered, they may compete for renal elimination; there is a large likelihood that one agent may "out-compete" or saturate the renal excretion mechanisms before the other concomitantly administered agent(s) are excreted. As a result, the elimination of these other concurrently administered agents may be inhibited or otherwise delayed, which could lead to increases in their serum concentrations and the risk, incidence, and/or severity of adverse effects associated with the exposure to such drugs. The severity of the interaction is minor.

Does Bupropion and Mycophenolic acid interact?

•Drug A: Bupropion •Drug B: Mycophenolic acid •Severity: MINOR •Description: Mycophenolic acid may decrease the excretion rate of Bupropion which could result in a higher serum level. •Extended Description: The renal excretion of drugs is the overall result of a combination of kidney processes that include glomerular filtration, passive diffusion, tubular secretion, and tubular reabsorption. Since two of these mechanisms - tubular secretion and reabsorption - are saturable processes , they are consequently susceptible to competition between multiple substrates excreted by the kidneys. If two or more medications that are mainly renally excreted are co-administered, they may compete for renal elimination; there is a large likelihood that one agent may "out-compete" or saturate the renal excretion mechanisms before the other concomitantly administered agent(s) are excreted. As a result, the elimination of these other concurrently administered agents may be inhibited or otherwise delayed, which could lead to increases in their serum concentrations and the risk, incidence, and/or severity of adverse effects associated with the exposure to such drugs. •Indication (Drug A): Bupropion is indicated for the treatment of major depressive disorder (MDD), seasonal affective disorder (SAD), and as an aid to smoking cessation. When used in combination with naltrexone as the marketed product ContraveⓇ, bupropion is indicated as an adjunct to a reduced-calorie diet and increased physical activity for chronic weight management in adults with an initial body mass index (BMI) of: 30 kg/m^2 or greater (obese) or 27 kg/m^2 or greater (overweight) in the presence of at least one weight-related comorbid condition (e.g., hypertension, type 2 diabetes mellitus, or dyslipidemia). Bupropion is also used off-label as a first-line treatment in patients with ADHD and comorbid bipolar disorder when used as an adjunct to mood stabilizers. •Indication (Drug B): Mycophenolic acid is an antimetabolite immunosuppressant indicated for prophylaxis of organ rejection in adult patients receiving kidney transplants and in pediatric patients at least 5 years of age and older who are at least 6 months post kidney transplant. Mycophenolic acid is used in combination with cyclosporine and corticosteroids. •Pharmacodynamics (Drug A): Bupropion is chemically unrelated to tricyclic, tetracyclic, selective serotonin re-uptake inhibitors, or other known antidepressant agents. Compared to classical tricyclic antidepressants, Bupropion is a relatively weak inhibitor of the neuronal uptake of norepinephrine and dopamine. In addition, Bupropion does not inhibit monoamine oxidase. Bupropion has been found to be essentially inactive at the serotonin transporter (SERT)(IC50 >10 000 nM), however both bupropion and its primary metabolite hydroxybupropion have been found to block the function of cation-selective serotonin type 3A receptors (5-HT3ARs). Bupropion produces dose-related central nervous system (CNS) stimulant effects in animals, as evidenced by increased locomotor activity, increased rates of responding in various schedule-controlled operant behaviour tasks, and, at high doses, induction of mild stereotyped behaviour. Due to these stimulant effects and selective activity at dopamine and norepinephrine receptors, bupropion has been identified as having an abuse potential. Bupropion has a similar structure to the controlled substance Cathinone, and has been identified as having mild amphetamine-like activity, particularly when inhaled or injected. Bupropion is also known to lower the seizure threshold, making any pre-existing seizure conditions a contraindication to its use. This risk is exacerbated when bupropion is combined with other drugs or substances that lower the seizure threshold, such as cocaine, or in clinical situations that would increase the risk of a seizure such as abrupt alcohol or benzodiazepine withdrawal. As norepinephrine has been shown to have anticonvulsant properties, bupropion's inhibitory effects on NET are thought to contribute to its pro-convulsant activity. Bupropion has been shown to increase blood pressure and pose a risk for exacerbation of unmanaged or pre-existing hypertension, however, clinical trials of bupropion in smokers with CVD have not identified an increased incidence of CV events including stroke or heart attack. In clinical trials, the mean increase in systolic blood pressure associated with the use of bupropion was found to be 1.3 mmHg. •Pharmacodynamics (Drug B): Mycophenolic acid is a potent inhibitor of inosine monophosphate dehydrogenase (IMPDH) that blocks de novo biosynthesis of purine nucleotides. This affects lymphocytes primarily and leads to the suppression of DNA synthesis in T- and B-cells. Mycophenolic acid arrests the T-lymphocyte cell cycle at the G1/S interface and inhibits the proliferation of lymphocytes. Also, it has been suggested that mycophenolic acid suppresses cytokine production by limiting the number of cytokine-producing cells. The enteric-coating of mycophenolic acid tablets prevents the development of upper gastrointestinal adverse events by delaying drug release until it reaches the small intestine. Patients treated with mycophenolic acid have a higher risk of developing new or reactivated viral infections, serious infections, blood dyscrasias (including pure red cell aplasia), serious gastrointestinal tract complications, acute inflammatory syndrome associated with mycophenolate products, lymphoma, and other malignancies. The use of mycophenolic acid is also associated with an increased risk of first-trimester pregnancy loss and congenital malformations. Mycophenolic acid should be avoided in patients with rare hereditary deficiency of hypoxanthine-guanine phosphoribosyl-transferase (HGPRT). Patients treated with mycophenolic acid should not receive live attenuated vaccines or donate blood or semen. •Mechanism of action (Drug A): Bupropion is a norepinephrine/dopamine-reuptake inhibitor (NDRI) that exerts its pharmacological effects by weakly inhibiting the enzymes involved in the uptake of the neurotransmitters norepinephrine and dopamine from the synaptic cleft, therefore prolonging their duration of action within the neuronal synapse and the downstream effects of these neurotransmitters. More specifically, bupropion binds to the norepinephrine transporter (NET) and the dopamine transporter (DAT). Bupropion was originally classified as an "atypical" antidepressant because it does not exert the same effects as the classical antidepressants such as Monoamine Oxidase Inhibitors (MAOIs), Tricyclic Antidepressants (TCAs), or Selective Serotonin Reuptake Inhibitors (SSRIs). While it has comparable effectiveness to typical first-line options for the treatment of depression such as SSRIs, bupropion is a unique option for the treatment of MDD as it lacks any clinically relevant serotonergic effects, typical of other mood medications, or any effects on histamine or adrenaline receptors. Lack of activity at these receptors results in a more tolerable side effect profile; bupropion is less likely to cause sexual side effects, sedation, or weight gain as compared to SSRIs or TCAs, for example. When used as an aid to smoking cessation, bupropion is thought to confer its anti-craving and anti-withdrawal effects by inhibiting dopamine reuptake, which is thought to be involved in the reward pathways associated with nicotine, and through the antagonism of the nicotinic acetylcholinergic receptor (AChR), thereby blunting the effects of nicotine. Furthermore, the stimulatory effects produced by bupropion in the central nervous system are similar to nicotine's effects, making low doses of bupropion a suitable option as a nicotine substitute. When used in combination with naltrexone in the marketed product ContraveⓇ for chronic weight management, the two components are thought to have effects on areas of the brain involved in the regulation of food intake. This includes the hypothalamus, which is involved in appetite regulation, and the mesolimbic dopamine circuit, which is involved in reward pathways. Studies have shown that the combined activity of bupropion and naltrexone increase the firing rate of hypothalamic pro-opiomelanocortin (POMC) neurons and blockade of opioid receptor-mediated POMC auto-inhibition, which are associated with a reduction in food intake and increased energy expenditure. This combination was also found to reduce food intake when injected directly into the ventral tegmental area of the mesolimbic circuit in mice, which is an area associated with the regulation of reward pathways. •Mechanism of action (Drug B): Mycophenolic acid is a selective noncompetitive and reversible inhibitor of inosine monophosphate dehydrogenase (IMPDH), that blocks the conversion of inosine-5-phosphate and xanthine-5-phosphate to guanosine-5-phosphate. By inhibiting IMPDH, mycophenolic acid interferes with the de novo pathway of guanosine nucleotide synthesis without incorporation into DNA. While other cell types are able to use salvage pathways, T- and B-lymphocyte proliferation is a mechanism heavily dependent on the de novo synthesis of purines. Therefore, mycophenolic acid has potent cytostatic effects on T- and B- and lymphocytes. Mycophenolic acid also suppresses antibody formation by B-lymphocytes and prevents the glycosylation of lymphocyte and monocyte glycoproteins involved in intercellular adhesion to endothelial cells. •Absorption (Drug A): Bupropion is currently available in 3 distinct, but bioequivalent formulations: immediate release (IR), sustained-release (SR), and extended-release (XL). Immediate Release Formulation In humans, following oral administration of bupropion hydrochloride tablets, peak plasma bupropion concentrations are usually achieved within 2 hours. IR formulations provide a short duration of action and are therefore generally dosed three times per day. Sustained Release Formulation In humans, following oral administration of bupropion hydrochloride sustained-release tablets (SR), peak plasma concentration (Cmax) of bupropion is usually achieved within 3 hours. SR formulations provide a 12-hour extended release of medication and are therefore generally dosed twice per day. Extended Release Formulation Following single oral administration of bupropion hydrochloride extended-release tablets (XL) to healthy volunteers, the median time to peak plasma concentrations for bupropion was approximately 5 hours. The presence of food did not affect the peak concentration or area under the curve of bupropion. XL formulations provide a 24-hour extended release of medication and are therefore generally dosed once per day/ In a trial comparing chronic dosing with bupropion hydrochloride extended-release tablets (SR) 150 mg twice daily to bupropion immediate-release formulation 100 mg 3 times daily, the steady state Cmax for bupropion after bupropion hydrochloride sustained-release tablets (SR) administration was approximately 85% of those achieved after bupropion immediate-release formulation administration. Exposure (AUC) to bupropion was equivalent for both formulations. Bioequivalence was also demonstrated for all three major active metabolites (i.e., hydroxybupropion, threohydrobupropion and erythrohydrobupropion) for both Cmax and AUC. Thus, at steady state, bupropion hydrochloride sustained-release tablets (SR) given twice daily, and the immediate-release formulation of bupropion given 3 times daily, are essentially bioequivalent for both bupropion and the 3 quantitatively important metabolites. Furthermore, in a study comparing 14-day dosing with bupropion hydrochloride extended-release tablets (XL), 300 mg once-daily to the immediate-release formulation of bupropion at 100 mg 3 times daily, equivalence was demonstrated for peak plasma concentration and area under the curve for bupropion and the three metabolites (hydroxybupropion, threohydrobupropion, and erythrohydrobupropion). Additionally, in a study comparing 14-day dosing with bupropion hydrochloride extended-release tablets (XL) 300 mg once daily to the sustained-release formulation of bupropion at 150 mg 2 times daily, equivalence was demonstrated for peak plasma concentration and area under the curve for bupropion and the three metabolites. Bupropion hydrochloride extended-release tablets (SR) can be taken with or without food. Bupropion Cmax and AUC were increased by 11% to 35% and 16% to 19%, respectively, when bupropion hydrochloride extended-release tablets (SR) was administered with food to healthy volunteers in three trials. The food effect is not considered clinically significant. Following a single-dose administration of bupropion hydrochloride extended-release tablets (SR) in humans, Cmax of bupropion's metabolite hydroxybupropion occurs approximately 6 hours post-dose and is approximately 10 times the peak level of the parent drug at steady state. The elimination half-life of hydroxybupropion is approximately 20 (±5) hours and its AUC at steady state is about 17 times that of bupropion. The times to peak concentrations for the erythrohydrobupropion and threohydrobupropion metabolites are similar to that of the hydroxybupropion metabolite. However, their elimination half-lives are longer, 33(±10) and 37 (±13) hours, respectively, and steady-state AUCs are 1.5 and 7 times that of bupropion, respectively. •Absorption (Drug B): Between 360 mg and 2,160 mg, mycophenolic acid follows a linear and dose-proportional pharmacokinetic profile. The enteric-coating of mycophenolic acid tablets prevents release under acidic conditions (stomach, pH < 5). However, enteric-coated mycophenolic acid tablets are highly soluble in neutral pH conditions such as those in the intestine. In renal transplant patients, the median delay (T lag ) in the rise of mycophenolic acid concentration ranged between 0.25 and 1.25 hours, and the T max ranged between 1.5 and 2.75 hours. Adult renal transplant patients on cyclosporine given mycophenolic acid had a T max of 2 h, a C max of 26.1 μg/mL, and an AUC 0-12 of 66.5 μg⋅h/mL. Stable pediatric (5-16 years old) renal transplant patients had a C max and AUC 33% and 18% higher than the ones detected in adults. In stable renal transplant patients treated with cyclosporine, the gastrointestinal absorption and absolute bioavailability of delayed-release tablets of mycophenolic acid were 93% and 72%, respectively. Following the administration of a high-fat meal (55 g fat, 1000 calories), the AUC of mycophenolic acid (enteric-coated tablets, 720 mg) was comparable to the one detected during fasting. However, a high-fat meal can lead to a 33% decrease of the C max, a 3.5-hour delay in the T lag (range of -6 to 18 hours), and a 5.0-hour delay in the T max (range of -9 to 20 hours). To avoid variability in the absorption of mycophenolic acid, this drug should be taken on an empty stomach. •Volume of distribution (Drug A): No volume of distribution available •Volume of distribution (Drug B): At steady state, the volume of distribution of mycophenolic acid is 54 L. At the elimination phase, the volume of distribution of mycophenolic acid is 112 L. •Protein binding (Drug A): In vitro tests show that bupropion is 84% bound to human plasma proteins at concentrations up to 200 mcg per mL. The extent of protein binding of the hydroxybupropion metabolite is similar to that for bupropion, whereas the extent of protein binding of the threohydrobupropion metabolite is about half that seen with bupropion. •Protein binding (Drug B): Mycophenolic acid is highly protein-bound, and more than 98% of it is bound to albumin. •Metabolism (Drug A): Bupropion is extensively metabolized in humans. Three metabolites are active: hydroxybupropion, which is formed via hydroxylation of the tert-butyl group of bupropion, and the amino-alcohol isomers, threohydrobupropion and erythrohydrobupropion, which are formed via reduction of the carbonyl group. In vitro findings suggest that CYP2B6 is the principal isoenzyme involved in the formation of hydroxybupropion, while cytochrome P450 enzymes are not involved in the formation of threohydrobupropion. Hydroxybupropion has been shown to have the same affinity as bupropion for the norepinephrine transporter (NET) but approximately 50% of its antidepressant activity despite reaching concentrations of ~10-fold higher than that of the parent drug. Oxidation of the bupropion side chain results in the formation of a glycine conjugate of meta-chlorobenzoic acid, which is then excreted as the major urinary metabolite. The potency and toxicity of the metabolites relative to bupropion have not been fully characterized. However, it has been demonstrated in an antidepressant screening test in mice that hydroxybupropion is one-half as potent as bupropion, while threohydrobupropion and erythrohydrobupropion are 5-fold less potent than bupropion. This may be of clinical importance because the plasma concentrations of the metabolites are as high as or higher than those of bupropion. Bupropion and its metabolites exhibit linear kinetics following chronic administration of 300 to 450 mg per day. •Metabolism (Drug B): Mycophenolic acid is mainly metabolized by glucuronyl transferase to form glucuronidated metabolites. Mycophenolic acid glucuronide (MPAG), the major metabolite of mycophenolic acid, does not display pharmacological activity. However, the acyl glucuronide minor metabolite has a pharmacological activity similar to mycophenolic acid. The AUC ratio of mycophenolic acid:MPAG:acyl glucuronide is approximately 1:24:0.28 at a steady state. •Route of elimination (Drug A): Bupropion is extensively metabolized in humans. Oxidation of the bupropion side chain results in the formation of a glycine conjugate of metachlorobenzoic acid, which is then excreted as the major urinary metabolite. Following oral administration of 200 mg of 14C-bupropion in humans, 87% and 10% of the radioactive dose were recovered in the urine and feces, respectively. However, the fraction of the oral dose of bupropion excreted unchanged was only 0.5%, a finding consistent with the extensive metabolism of bupropion. •Route of elimination (Drug B): In stable renal transplant patients, approximately 60% of mycophenolic acid is eliminated in the urine as mycophenolic acid glucuronide (MPAG), while 3% is eliminated unchanged. MPAG is also secreted in the bile and is available for deconjugation by gut flora. The mycophenolic acid that results from MPAG deconjugation may be reabsorbed and produce a second peak 6-8 hours after administration. •Half-life (Drug A): 24 hours •Half-life (Drug B): The mean elimination half-life of mycophenolic acid ranges between 8 and 16 hours, while the mean elimination half-life of mycophenolic acid glucuronide, its major metabolite, ranges between 13 and 17 hours. •Clearance (Drug A): No clearance available •Clearance (Drug B): The mean clearance of mycophenolic acid is 140 mL/min. The mean renal clearance of its metabolite, mycophenolic acid glucuronide, is 15.5 mL/min. •Toxicity (Drug A): Symptoms of overdose include seizures, hallucinations, loss of consciousness, tachycardia, and cardiac arrest. •Toxicity (Drug B): There are anecdotal reports of deliberate or accidental overdoses with mycophenolic acid; however, not all patients have experienced related adverse reactions. In those cases where adverse reactions have been reported, reactions fall within the safety profile of its class of drugs. A mycophenolic acid overdose could lead to the oversuppression of the immune system and increase the susceptibility to infection. It may be appropriate to interrupt or discontinue mycophenolic acid if blood dyscrasias occur. Some of the signs and symptoms associated with mycophenolic acid overdose are hematological abnormalities, such as leukopenia and neutropenia, and gastrointestinal symptoms, such as abdominal pain, diarrhea, nausea and vomiting, and dyspepsia. Carcinogenicity studies of 104 weeks done in rats and mice, suggest that mycophenolate sodium does not induce the formation of tumours. Rats were given up to 9 mg/kg of mycophenolate sodium, which corresponded to 0.6-1.2 times the systemic exposure observed in renal transplant patients, while mice were given 180 mg/kg, an equivalent of 0.6 times the mycophenolate sodium therapeutic dose. The genotoxicity of mycophenolate sodium was confirmed by the mouse lymphoma/thymidine kinase assay, the micronucleus test in V79 Chinese hamster cells, and the in vivo mouse micronucleus assay. Mycophenolate mofetil, a prodrug of mycophenolic acid, had a similar genotoxic profile. At daily oral doses as high as 18 mg/kg and 20 mg/kg, mycophenolate sodium had no effect on male and female rat fertility, respectively. The oral LD 50 of mycophenolic acid is 352 mg/kg in rats and 1000 mg/kg in mice. •Brand Names (Drug A): Aplenzin, Auvelity, Budeprion, Contrave, Forfivo, Wellbutrin, Zyban •Brand Names (Drug B): Myfortic •Synonyms (Drug A): No synonyms listed •Synonyms (Drug B): Acide mycophenolique Acido micofenolico Acidum mycophenolicum Micofenolico acido Mycophenolate Mycophenolic acid Mycophenolsäure •Summary (Drug A): Bupropion is a norepinephrine and dopamine reuptake inhibitor used in the treatment of major depressive disorder (MDD), seasonal affective disorder (SAD), and as an aid to smoking cessation. •Summary (Drug B): Mycophenolic acid is an immunosuppressant used to prevent organ transplant rejections.

The renal excretion of drugs is the overall result of a combination of kidney processes that include glomerular filtration, passive diffusion, tubular secretion, and tubular reabsorption. Since two of these mechanisms - tubular secretion and reabsorption - are saturable processes , they are consequently susceptible to competition between multiple substrates excreted by the kidneys. If two or more medications that are mainly renally excreted are co-administered, they may compete for renal elimination; there is a large likelihood that one agent may "out-compete" or saturate the renal excretion mechanisms before the other concomitantly administered agent(s) are excreted. As a result, the elimination of these other concurrently administered agents may be inhibited or otherwise delayed, which could lead to increases in their serum concentrations and the risk, incidence, and/or severity of adverse effects associated with the exposure to such drugs. The severity of the interaction is minor.

Question: Does Bupropion and Mycophenolic acid interact? Information: •Drug A: Bupropion •Drug B: Mycophenolic acid •Severity: MINOR •Description: Mycophenolic acid may decrease the excretion rate of Bupropion which could result in a higher serum level. •Extended Description: The renal excretion of drugs is the overall result of a combination of kidney processes that include glomerular filtration, passive diffusion, tubular secretion, and tubular reabsorption. Since two of these mechanisms - tubular secretion and reabsorption - are saturable processes , they are consequently susceptible to competition between multiple substrates excreted by the kidneys. If two or more medications that are mainly renally excreted are co-administered, they may compete for renal elimination; there is a large likelihood that one agent may "out-compete" or saturate the renal excretion mechanisms before the other concomitantly administered agent(s) are excreted. As a result, the elimination of these other concurrently administered agents may be inhibited or otherwise delayed, which could lead to increases in their serum concentrations and the risk, incidence, and/or severity of adverse effects associated with the exposure to such drugs. •Indication (Drug A): Bupropion is indicated for the treatment of major depressive disorder (MDD), seasonal affective disorder (SAD), and as an aid to smoking cessation. When used in combination with naltrexone as the marketed product ContraveⓇ, bupropion is indicated as an adjunct to a reduced-calorie diet and increased physical activity for chronic weight management in adults with an initial body mass index (BMI) of: 30 kg/m^2 or greater (obese) or 27 kg/m^2 or greater (overweight) in the presence of at least one weight-related comorbid condition (e.g., hypertension, type 2 diabetes mellitus, or dyslipidemia). Bupropion is also used off-label as a first-line treatment in patients with ADHD and comorbid bipolar disorder when used as an adjunct to mood stabilizers. •Indication (Drug B): Mycophenolic acid is an antimetabolite immunosuppressant indicated for prophylaxis of organ rejection in adult patients receiving kidney transplants and in pediatric patients at least 5 years of age and older who are at least 6 months post kidney transplant. Mycophenolic acid is used in combination with cyclosporine and corticosteroids. •Pharmacodynamics (Drug A): Bupropion is chemically unrelated to tricyclic, tetracyclic, selective serotonin re-uptake inhibitors, or other known antidepressant agents. Compared to classical tricyclic antidepressants, Bupropion is a relatively weak inhibitor of the neuronal uptake of norepinephrine and dopamine. In addition, Bupropion does not inhibit monoamine oxidase. Bupropion has been found to be essentially inactive at the serotonin transporter (SERT)(IC50 >10 000 nM), however both bupropion and its primary metabolite hydroxybupropion have been found to block the function of cation-selective serotonin type 3A receptors (5-HT3ARs). Bupropion produces dose-related central nervous system (CNS) stimulant effects in animals, as evidenced by increased locomotor activity, increased rates of responding in various schedule-controlled operant behaviour tasks, and, at high doses, induction of mild stereotyped behaviour. Due to these stimulant effects and selective activity at dopamine and norepinephrine receptors, bupropion has been identified as having an abuse potential. Bupropion has a similar structure to the controlled substance Cathinone, and has been identified as having mild amphetamine-like activity, particularly when inhaled or injected. Bupropion is also known to lower the seizure threshold, making any pre-existing seizure conditions a contraindication to its use. This risk is exacerbated when bupropion is combined with other drugs or substances that lower the seizure threshold, such as cocaine, or in clinical situations that would increase the risk of a seizure such as abrupt alcohol or benzodiazepine withdrawal. As norepinephrine has been shown to have anticonvulsant properties, bupropion's inhibitory effects on NET are thought to contribute to its pro-convulsant activity. Bupropion has been shown to increase blood pressure and pose a risk for exacerbation of unmanaged or pre-existing hypertension, however, clinical trials of bupropion in smokers with CVD have not identified an increased incidence of CV events including stroke or heart attack. In clinical trials, the mean increase in systolic blood pressure associated with the use of bupropion was found to be 1.3 mmHg. •Pharmacodynamics (Drug B): Mycophenolic acid is a potent inhibitor of inosine monophosphate dehydrogenase (IMPDH) that blocks de novo biosynthesis of purine nucleotides. This affects lymphocytes primarily and leads to the suppression of DNA synthesis in T- and B-cells. Mycophenolic acid arrests the T-lymphocyte cell cycle at the G1/S interface and inhibits the proliferation of lymphocytes. Also, it has been suggested that mycophenolic acid suppresses cytokine production by limiting the number of cytokine-producing cells. The enteric-coating of mycophenolic acid tablets prevents the development of upper gastrointestinal adverse events by delaying drug release until it reaches the small intestine. Patients treated with mycophenolic acid have a higher risk of developing new or reactivated viral infections, serious infections, blood dyscrasias (including pure red cell aplasia), serious gastrointestinal tract complications, acute inflammatory syndrome associated with mycophenolate products, lymphoma, and other malignancies. The use of mycophenolic acid is also associated with an increased risk of first-trimester pregnancy loss and congenital malformations. Mycophenolic acid should be avoided in patients with rare hereditary deficiency of hypoxanthine-guanine phosphoribosyl-transferase (HGPRT). Patients treated with mycophenolic acid should not receive live attenuated vaccines or donate blood or semen. •Mechanism of action (Drug A): Bupropion is a norepinephrine/dopamine-reuptake inhibitor (NDRI) that exerts its pharmacological effects by weakly inhibiting the enzymes involved in the uptake of the neurotransmitters norepinephrine and dopamine from the synaptic cleft, therefore prolonging their duration of action within the neuronal synapse and the downstream effects of these neurotransmitters. More specifically, bupropion binds to the norepinephrine transporter (NET) and the dopamine transporter (DAT). Bupropion was originally classified as an "atypical" antidepressant because it does not exert the same effects as the classical antidepressants such as Monoamine Oxidase Inhibitors (MAOIs), Tricyclic Antidepressants (TCAs), or Selective Serotonin Reuptake Inhibitors (SSRIs). While it has comparable effectiveness to typical first-line options for the treatment of depression such as SSRIs, bupropion is a unique option for the treatment of MDD as it lacks any clinically relevant serotonergic effects, typical of other mood medications, or any effects on histamine or adrenaline receptors. Lack of activity at these receptors results in a more tolerable side effect profile; bupropion is less likely to cause sexual side effects, sedation, or weight gain as compared to SSRIs or TCAs, for example. When used as an aid to smoking cessation, bupropion is thought to confer its anti-craving and anti-withdrawal effects by inhibiting dopamine reuptake, which is thought to be involved in the reward pathways associated with nicotine, and through the antagonism of the nicotinic acetylcholinergic receptor (AChR), thereby blunting the effects of nicotine. Furthermore, the stimulatory effects produced by bupropion in the central nervous system are similar to nicotine's effects, making low doses of bupropion a suitable option as a nicotine substitute. When used in combination with naltrexone in the marketed product ContraveⓇ for chronic weight management, the two components are thought to have effects on areas of the brain involved in the regulation of food intake. This includes the hypothalamus, which is involved in appetite regulation, and the mesolimbic dopamine circuit, which is involved in reward pathways. Studies have shown that the combined activity of bupropion and naltrexone increase the firing rate of hypothalamic pro-opiomelanocortin (POMC) neurons and blockade of opioid receptor-mediated POMC auto-inhibition, which are associated with a reduction in food intake and increased energy expenditure. This combination was also found to reduce food intake when injected directly into the ventral tegmental area of the mesolimbic circuit in mice, which is an area associated with the regulation of reward pathways. •Mechanism of action (Drug B): Mycophenolic acid is a selective noncompetitive and reversible inhibitor of inosine monophosphate dehydrogenase (IMPDH), that blocks the conversion of inosine-5-phosphate and xanthine-5-phosphate to guanosine-5-phosphate. By inhibiting IMPDH, mycophenolic acid interferes with the de novo pathway of guanosine nucleotide synthesis without incorporation into DNA. While other cell types are able to use salvage pathways, T- and B-lymphocyte proliferation is a mechanism heavily dependent on the de novo synthesis of purines. Therefore, mycophenolic acid has potent cytostatic effects on T- and B- and lymphocytes. Mycophenolic acid also suppresses antibody formation by B-lymphocytes and prevents the glycosylation of lymphocyte and monocyte glycoproteins involved in intercellular adhesion to endothelial cells. •Absorption (Drug A): Bupropion is currently available in 3 distinct, but bioequivalent formulations: immediate release (IR), sustained-release (SR), and extended-release (XL). Immediate Release Formulation In humans, following oral administration of bupropion hydrochloride tablets, peak plasma bupropion concentrations are usually achieved within 2 hours. IR formulations provide a short duration of action and are therefore generally dosed three times per day. Sustained Release Formulation In humans, following oral administration of bupropion hydrochloride sustained-release tablets (SR), peak plasma concentration (Cmax) of bupropion is usually achieved within 3 hours. SR formulations provide a 12-hour extended release of medication and are therefore generally dosed twice per day. Extended Release Formulation Following single oral administration of bupropion hydrochloride extended-release tablets (XL) to healthy volunteers, the median time to peak plasma concentrations for bupropion was approximately 5 hours. The presence of food did not affect the peak concentration or area under the curve of bupropion. XL formulations provide a 24-hour extended release of medication and are therefore generally dosed once per day/ In a trial comparing chronic dosing with bupropion hydrochloride extended-release tablets (SR) 150 mg twice daily to bupropion immediate-release formulation 100 mg 3 times daily, the steady state Cmax for bupropion after bupropion hydrochloride sustained-release tablets (SR) administration was approximately 85% of those achieved after bupropion immediate-release formulation administration. Exposure (AUC) to bupropion was equivalent for both formulations. Bioequivalence was also demonstrated for all three major active metabolites (i.e., hydroxybupropion, threohydrobupropion and erythrohydrobupropion) for both Cmax and AUC. Thus, at steady state, bupropion hydrochloride sustained-release tablets (SR) given twice daily, and the immediate-release formulation of bupropion given 3 times daily, are essentially bioequivalent for both bupropion and the 3 quantitatively important metabolites. Furthermore, in a study comparing 14-day dosing with bupropion hydrochloride extended-release tablets (XL), 300 mg once-daily to the immediate-release formulation of bupropion at 100 mg 3 times daily, equivalence was demonstrated for peak plasma concentration and area under the curve for bupropion and the three metabolites (hydroxybupropion, threohydrobupropion, and erythrohydrobupropion). Additionally, in a study comparing 14-day dosing with bupropion hydrochloride extended-release tablets (XL) 300 mg once daily to the sustained-release formulation of bupropion at 150 mg 2 times daily, equivalence was demonstrated for peak plasma concentration and area under the curve for bupropion and the three metabolites. Bupropion hydrochloride extended-release tablets (SR) can be taken with or without food. Bupropion Cmax and AUC were increased by 11% to 35% and 16% to 19%, respectively, when bupropion hydrochloride extended-release tablets (SR) was administered with food to healthy volunteers in three trials. The food effect is not considered clinically significant. Following a single-dose administration of bupropion hydrochloride extended-release tablets (SR) in humans, Cmax of bupropion's metabolite hydroxybupropion occurs approximately 6 hours post-dose and is approximately 10 times the peak level of the parent drug at steady state. The elimination half-life of hydroxybupropion is approximately 20 (±5) hours and its AUC at steady state is about 17 times that of bupropion. The times to peak concentrations for the erythrohydrobupropion and threohydrobupropion metabolites are similar to that of the hydroxybupropion metabolite. However, their elimination half-lives are longer, 33(±10) and 37 (±13) hours, respectively, and steady-state AUCs are 1.5 and 7 times that of bupropion, respectively. •Absorption (Drug B): Between 360 mg and 2,160 mg, mycophenolic acid follows a linear and dose-proportional pharmacokinetic profile. The enteric-coating of mycophenolic acid tablets prevents release under acidic conditions (stomach, pH < 5). However, enteric-coated mycophenolic acid tablets are highly soluble in neutral pH conditions such as those in the intestine. In renal transplant patients, the median delay (T lag ) in the rise of mycophenolic acid concentration ranged between 0.25 and 1.25 hours, and the T max ranged between 1.5 and 2.75 hours. Adult renal transplant patients on cyclosporine given mycophenolic acid had a T max of 2 h, a C max of 26.1 μg/mL, and an AUC 0-12 of 66.5 μg⋅h/mL. Stable pediatric (5-16 years old) renal transplant patients had a C max and AUC 33% and 18% higher than the ones detected in adults. In stable renal transplant patients treated with cyclosporine, the gastrointestinal absorption and absolute bioavailability of delayed-release tablets of mycophenolic acid were 93% and 72%, respectively. Following the administration of a high-fat meal (55 g fat, 1000 calories), the AUC of mycophenolic acid (enteric-coated tablets, 720 mg) was comparable to the one detected during fasting. However, a high-fat meal can lead to a 33% decrease of the C max, a 3.5-hour delay in the T lag (range of -6 to 18 hours), and a 5.0-hour delay in the T max (range of -9 to 20 hours). To avoid variability in the absorption of mycophenolic acid, this drug should be taken on an empty stomach. •Volume of distribution (Drug A): No volume of distribution available •Volume of distribution (Drug B): At steady state, the volume of distribution of mycophenolic acid is 54 L. At the elimination phase, the volume of distribution of mycophenolic acid is 112 L. •Protein binding (Drug A): In vitro tests show that bupropion is 84% bound to human plasma proteins at concentrations up to 200 mcg per mL. The extent of protein binding of the hydroxybupropion metabolite is similar to that for bupropion, whereas the extent of protein binding of the threohydrobupropion metabolite is about half that seen with bupropion. •Protein binding (Drug B): Mycophenolic acid is highly protein-bound, and more than 98% of it is bound to albumin. •Metabolism (Drug A): Bupropion is extensively metabolized in humans. Three metabolites are active: hydroxybupropion, which is formed via hydroxylation of the tert-butyl group of bupropion, and the amino-alcohol isomers, threohydrobupropion and erythrohydrobupropion, which are formed via reduction of the carbonyl group. In vitro findings suggest that CYP2B6 is the principal isoenzyme involved in the formation of hydroxybupropion, while cytochrome P450 enzymes are not involved in the formation of threohydrobupropion. Hydroxybupropion has been shown to have the same affinity as bupropion for the norepinephrine transporter (NET) but approximately 50% of its antidepressant activity despite reaching concentrations of ~10-fold higher than that of the parent drug. Oxidation of the bupropion side chain results in the formation of a glycine conjugate of meta-chlorobenzoic acid, which is then excreted as the major urinary metabolite. The potency and toxicity of the metabolites relative to bupropion have not been fully characterized. However, it has been demonstrated in an antidepressant screening test in mice that hydroxybupropion is one-half as potent as bupropion, while threohydrobupropion and erythrohydrobupropion are 5-fold less potent than bupropion. This may be of clinical importance because the plasma concentrations of the metabolites are as high as or higher than those of bupropion. Bupropion and its metabolites exhibit linear kinetics following chronic administration of 300 to 450 mg per day. •Metabolism (Drug B): Mycophenolic acid is mainly metabolized by glucuronyl transferase to form glucuronidated metabolites. Mycophenolic acid glucuronide (MPAG), the major metabolite of mycophenolic acid, does not display pharmacological activity. However, the acyl glucuronide minor metabolite has a pharmacological activity similar to mycophenolic acid. The AUC ratio of mycophenolic acid:MPAG:acyl glucuronide is approximately 1:24:0.28 at a steady state. •Route of elimination (Drug A): Bupropion is extensively metabolized in humans. Oxidation of the bupropion side chain results in the formation of a glycine conjugate of metachlorobenzoic acid, which is then excreted as the major urinary metabolite. Following oral administration of 200 mg of 14C-bupropion in humans, 87% and 10% of the radioactive dose were recovered in the urine and feces, respectively. However, the fraction of the oral dose of bupropion excreted unchanged was only 0.5%, a finding consistent with the extensive metabolism of bupropion. •Route of elimination (Drug B): In stable renal transplant patients, approximately 60% of mycophenolic acid is eliminated in the urine as mycophenolic acid glucuronide (MPAG), while 3% is eliminated unchanged. MPAG is also secreted in the bile and is available for deconjugation by gut flora. The mycophenolic acid that results from MPAG deconjugation may be reabsorbed and produce a second peak 6-8 hours after administration. •Half-life (Drug A): 24 hours •Half-life (Drug B): The mean elimination half-life of mycophenolic acid ranges between 8 and 16 hours, while the mean elimination half-life of mycophenolic acid glucuronide, its major metabolite, ranges between 13 and 17 hours. •Clearance (Drug A): No clearance available •Clearance (Drug B): The mean clearance of mycophenolic acid is 140 mL/min. The mean renal clearance of its metabolite, mycophenolic acid glucuronide, is 15.5 mL/min. •Toxicity (Drug A): Symptoms of overdose include seizures, hallucinations, loss of consciousness, tachycardia, and cardiac arrest. •Toxicity (Drug B): There are anecdotal reports of deliberate or accidental overdoses with mycophenolic acid; however, not all patients have experienced related adverse reactions. In those cases where adverse reactions have been reported, reactions fall within the safety profile of its class of drugs. A mycophenolic acid overdose could lead to the oversuppression of the immune system and increase the susceptibility to infection. It may be appropriate to interrupt or discontinue mycophenolic acid if blood dyscrasias occur. Some of the signs and symptoms associated with mycophenolic acid overdose are hematological abnormalities, such as leukopenia and neutropenia, and gastrointestinal symptoms, such as abdominal pain, diarrhea, nausea and vomiting, and dyspepsia. Carcinogenicity studies of 104 weeks done in rats and mice, suggest that mycophenolate sodium does not induce the formation of tumours. Rats were given up to 9 mg/kg of mycophenolate sodium, which corresponded to 0.6-1.2 times the systemic exposure observed in renal transplant patients, while mice were given 180 mg/kg, an equivalent of 0.6 times the mycophenolate sodium therapeutic dose. The genotoxicity of mycophenolate sodium was confirmed by the mouse lymphoma/thymidine kinase assay, the micronucleus test in V79 Chinese hamster cells, and the in vivo mouse micronucleus assay. Mycophenolate mofetil, a prodrug of mycophenolic acid, had a similar genotoxic profile. At daily oral doses as high as 18 mg/kg and 20 mg/kg, mycophenolate sodium had no effect on male and female rat fertility, respectively. The oral LD 50 of mycophenolic acid is 352 mg/kg in rats and 1000 mg/kg in mice. •Brand Names (Drug A): Aplenzin, Auvelity, Budeprion, Contrave, Forfivo, Wellbutrin, Zyban •Brand Names (Drug B): Myfortic •Synonyms (Drug A): No synonyms listed •Synonyms (Drug B): Acide mycophenolique Acido micofenolico Acidum mycophenolicum Micofenolico acido Mycophenolate Mycophenolic acid Mycophenolsäure •Summary (Drug A): Bupropion is a norepinephrine and dopamine reuptake inhibitor used in the treatment of major depressive disorder (MDD), seasonal affective disorder (SAD), and as an aid to smoking cessation. •Summary (Drug B): Mycophenolic acid is an immunosuppressant used to prevent organ transplant rejections. Output: The renal excretion of drugs is the overall result of a combination of kidney processes that include glomerular filtration, passive diffusion, tubular secretion, and tubular reabsorption. Since two of these mechanisms - tubular secretion and reabsorption - are saturable processes , they are consequently susceptible to competition between multiple substrates excreted by the kidneys. If two or more medications that are mainly renally excreted are co-administered, they may compete for renal elimination; there is a large likelihood that one agent may "out-compete" or saturate the renal excretion mechanisms before the other concomitantly administered agent(s) are excreted. As a result, the elimination of these other concurrently administered agents may be inhibited or otherwise delayed, which could lead to increases in their serum concentrations and the risk, incidence, and/or severity of adverse effects associated with the exposure to such drugs. The severity of the interaction is minor.

Does Bupropion and Nabilone interact?

•Drug A: Bupropion •Drug B: Nabilone •Severity: MODERATE •Description: Nabilone may increase the central nervous system depressant (CNS depressant) activities of Bupropion. •Extended Description: Nabilone has a CNS depressant effect, which may enhance the effects of central nervous system depressants. It may increase side effects such as dizziness, drowsiness, confusion, and difficulty concentrating, and may result in coma and death. •Indication (Drug A): Bupropion is indicated for the treatment of major depressive disorder (MDD), seasonal affective disorder (SAD), and as an aid to smoking cessation. When used in combination with naltrexone as the marketed product ContraveⓇ, bupropion is indicated as an adjunct to a reduced-calorie diet and increased physical activity for chronic weight management in adults with an initial body mass index (BMI) of: 30 kg/m^2 or greater (obese) or 27 kg/m^2 or greater (overweight) in the presence of at least one weight-related comorbid condition (e.g., hypertension, type 2 diabetes mellitus, or dyslipidemia). Bupropion is also used off-label as a first-line treatment in patients with ADHD and comorbid bipolar disorder when used as an adjunct to mood stabilizers. •Indication (Drug B): Nabilone is indicated for the treatment of the nausea and vomiting associated with cancer chemotherapy in patients who have failed to respond adequately to conventional antiemetic treatments. This restriction is required because a substantial proportion of any group of patients treated with Nabilone can be expected to experience disturbing psychotomimetic reactions not observed with other antiemetic agents. •Pharmacodynamics (Drug A): Bupropion is chemically unrelated to tricyclic, tetracyclic, selective serotonin re-uptake inhibitors, or other known antidepressant agents. Compared to classical tricyclic antidepressants, Bupropion is a relatively weak inhibitor of the neuronal uptake of norepinephrine and dopamine. In addition, Bupropion does not inhibit monoamine oxidase. Bupropion has been found to be essentially inactive at the serotonin transporter (SERT)(IC50 >10 000 nM), however both bupropion and its primary metabolite hydroxybupropion have been found to block the function of cation-selective serotonin type 3A receptors (5-HT3ARs). Bupropion produces dose-related central nervous system (CNS) stimulant effects in animals, as evidenced by increased locomotor activity, increased rates of responding in various schedule-controlled operant behaviour tasks, and, at high doses, induction of mild stereotyped behaviour. Due to these stimulant effects and selective activity at dopamine and norepinephrine receptors, bupropion has been identified as having an abuse potential. Bupropion has a similar structure to the controlled substance Cathinone, and has been identified as having mild amphetamine-like activity, particularly when inhaled or injected. Bupropion is also known to lower the seizure threshold, making any pre-existing seizure conditions a contraindication to its use. This risk is exacerbated when bupropion is combined with other drugs or substances that lower the seizure threshold, such as cocaine, or in clinical situations that would increase the risk of a seizure such as abrupt alcohol or benzodiazepine withdrawal. As norepinephrine has been shown to have anticonvulsant properties, bupropion's inhibitory effects on NET are thought to contribute to its pro-convulsant activity. Bupropion has been shown to increase blood pressure and pose a risk for exacerbation of unmanaged or pre-existing hypertension, however, clinical trials of bupropion in smokers with CVD have not identified an increased incidence of CV events including stroke or heart attack. In clinical trials, the mean increase in systolic blood pressure associated with the use of bupropion was found to be 1.3 mmHg. •Pharmacodynamics (Drug B): Nabilone is a cannabinoid with therapeutic uses. It is an analog of dronabinol (also known as tetrahydrocannabinol or THC), the psychoactive ingredient in cannabis. Although structurally distinct from THC, nabilone mimics THC's structure and pharmacological activity through weak partial agonist activity at Cannabinoid-1 (CB1R) and Cannabinoid-2 (CB2R) receptors, however it is considered to be twice as active as Δ⁹-THC. •Mechanism of action (Drug A): Bupropion is a norepinephrine/dopamine-reuptake inhibitor (NDRI) that exerts its pharmacological effects by weakly inhibiting the enzymes involved in the uptake of the neurotransmitters norepinephrine and dopamine from the synaptic cleft, therefore prolonging their duration of action within the neuronal synapse and the downstream effects of these neurotransmitters. More specifically, bupropion binds to the norepinephrine transporter (NET) and the dopamine transporter (DAT). Bupropion was originally classified as an "atypical" antidepressant because it does not exert the same effects as the classical antidepressants such as Monoamine Oxidase Inhibitors (MAOIs), Tricyclic Antidepressants (TCAs), or Selective Serotonin Reuptake Inhibitors (SSRIs). While it has comparable effectiveness to typical first-line options for the treatment of depression such as SSRIs, bupropion is a unique option for the treatment of MDD as it lacks any clinically relevant serotonergic effects, typical of other mood medications, or any effects on histamine or adrenaline receptors. Lack of activity at these receptors results in a more tolerable side effect profile; bupropion is less likely to cause sexual side effects, sedation, or weight gain as compared to SSRIs or TCAs, for example. When used as an aid to smoking cessation, bupropion is thought to confer its anti-craving and anti-withdrawal effects by inhibiting dopamine reuptake, which is thought to be involved in the reward pathways associated with nicotine, and through the antagonism of the nicotinic acetylcholinergic receptor (AChR), thereby blunting the effects of nicotine. Furthermore, the stimulatory effects produced by bupropion in the central nervous system are similar to nicotine's effects, making low doses of bupropion a suitable option as a nicotine substitute. When used in combination with naltrexone in the marketed product ContraveⓇ for chronic weight management, the two components are thought to have effects on areas of the brain involved in the regulation of food intake. This includes the hypothalamus, which is involved in appetite regulation, and the mesolimbic dopamine circuit, which is involved in reward pathways. Studies have shown that the combined activity of bupropion and naltrexone increase the firing rate of hypothalamic pro-opiomelanocortin (POMC) neurons and blockade of opioid receptor-mediated POMC auto-inhibition, which are associated with a reduction in food intake and increased energy expenditure. This combination was also found to reduce food intake when injected directly into the ventral tegmental area of the mesolimbic circuit in mice, which is an area associated with the regulation of reward pathways. •Mechanism of action (Drug B): Nabilone is an orally active synthetic cannabinoid which, like other cannabinoids, has complex effects on the central nervous system (CNS). It has been suggested that the antiemetic effect of nabilone is caused by interaction with the cannabinoid receptor system, i.e., the CB (1) receptor, which is a component of the endocannabinoid system of the body. The endocannabinoid system is widely distributed throughout the central and peripheral nervous system (via the Cannabinoid Receptors CB1 and CB2) and plays a role in many physiological processes such as inflammation, cardiovascular function, learning, pain, memory, stress and emotional regulation, and the sleep/wake cycle among many others. CB1 receptors are found in both the central and peripheral nervous system, and are most abundant in the hippocampus and amygdala, which are the areas of the brain responsible for short-term memory storage and emotional regulation. CB2 receptors are mainly located in the peripheral nervous system and can be found on lymphoid tissue where they are involved in regulation of immune function. •Absorption (Drug A): Bupropion is currently available in 3 distinct, but bioequivalent formulations: immediate release (IR), sustained-release (SR), and extended-release (XL). Immediate Release Formulation In humans, following oral administration of bupropion hydrochloride tablets, peak plasma bupropion concentrations are usually achieved within 2 hours. IR formulations provide a short duration of action and are therefore generally dosed three times per day. Sustained Release Formulation In humans, following oral administration of bupropion hydrochloride sustained-release tablets (SR), peak plasma concentration (Cmax) of bupropion is usually achieved within 3 hours. SR formulations provide a 12-hour extended release of medication and are therefore generally dosed twice per day. Extended Release Formulation Following single oral administration of bupropion hydrochloride extended-release tablets (XL) to healthy volunteers, the median time to peak plasma concentrations for bupropion was approximately 5 hours. The presence of food did not affect the peak concentration or area under the curve of bupropion. XL formulations provide a 24-hour extended release of medication and are therefore generally dosed once per day/ In a trial comparing chronic dosing with bupropion hydrochloride extended-release tablets (SR) 150 mg twice daily to bupropion immediate-release formulation 100 mg 3 times daily, the steady state Cmax for bupropion after bupropion hydrochloride sustained-release tablets (SR) administration was approximately 85% of those achieved after bupropion immediate-release formulation administration. Exposure (AUC) to bupropion was equivalent for both formulations. Bioequivalence was also demonstrated for all three major active metabolites (i.e., hydroxybupropion, threohydrobupropion and erythrohydrobupropion) for both Cmax and AUC. Thus, at steady state, bupropion hydrochloride sustained-release tablets (SR) given twice daily, and the immediate-release formulation of bupropion given 3 times daily, are essentially bioequivalent for both bupropion and the 3 quantitatively important metabolites. Furthermore, in a study comparing 14-day dosing with bupropion hydrochloride extended-release tablets (XL), 300 mg once-daily to the immediate-release formulation of bupropion at 100 mg 3 times daily, equivalence was demonstrated for peak plasma concentration and area under the curve for bupropion and the three metabolites (hydroxybupropion, threohydrobupropion, and erythrohydrobupropion). Additionally, in a study comparing 14-day dosing with bupropion hydrochloride extended-release tablets (XL) 300 mg once daily to the sustained-release formulation of bupropion at 150 mg 2 times daily, equivalence was demonstrated for peak plasma concentration and area under the curve for bupropion and the three metabolites. Bupropion hydrochloride extended-release tablets (SR) can be taken with or without food. Bupropion Cmax and AUC were increased by 11% to 35% and 16% to 19%, respectively, when bupropion hydrochloride extended-release tablets (SR) was administered with food to healthy volunteers in three trials. The food effect is not considered clinically significant. Following a single-dose administration of bupropion hydrochloride extended-release tablets (SR) in humans, Cmax of bupropion's metabolite hydroxybupropion occurs approximately 6 hours post-dose and is approximately 10 times the peak level of the parent drug at steady state. The elimination half-life of hydroxybupropion is approximately 20 (±5) hours and its AUC at steady state is about 17 times that of bupropion. The times to peak concentrations for the erythrohydrobupropion and threohydrobupropion metabolites are similar to that of the hydroxybupropion metabolite. However, their elimination half-lives are longer, 33(±10) and 37 (±13) hours, respectively, and steady-state AUCs are 1.5 and 7 times that of bupropion, respectively. •Absorption (Drug B): Nabilone appears to be completely absorbed from the human gastrointestinal tract when administered orally. Following oral administration of a 2 mg dose of radiolabeled nabilone, peak plasma concentrations of approximately 2 ng/mL nabilone and 10 ng equivalents/mL total radioactivity are achieved within 2.0 hours. •Volume of distribution (Drug A): No volume of distribution available •Volume of distribution (Drug B): The apparent volume of distribution of nabilone is about 12.5 L/kg. •Protein binding (Drug A): In vitro tests show that bupropion is 84% bound to human plasma proteins at concentrations up to 200 mcg per mL. The extent of protein binding of the hydroxybupropion metabolite is similar to that for bupropion, whereas the extent of protein binding of the threohydrobupropion metabolite is about half that seen with bupropion. •Protein binding (Drug B): No protein binding available •Metabolism (Drug A): Bupropion is extensively metabolized in humans. Three metabolites are active: hydroxybupropion, which is formed via hydroxylation of the tert-butyl group of bupropion, and the amino-alcohol isomers, threohydrobupropion and erythrohydrobupropion, which are formed via reduction of the carbonyl group. In vitro findings suggest that CYP2B6 is the principal isoenzyme involved in the formation of hydroxybupropion, while cytochrome P450 enzymes are not involved in the formation of threohydrobupropion. Hydroxybupropion has been shown to have the same affinity as bupropion for the norepinephrine transporter (NET) but approximately 50% of its antidepressant activity despite reaching concentrations of ~10-fold higher than that of the parent drug. Oxidation of the bupropion side chain results in the formation of a glycine conjugate of meta-chlorobenzoic acid, which is then excreted as the major urinary metabolite. The potency and toxicity of the metabolites relative to bupropion have not been fully characterized. However, it has been demonstrated in an antidepressant screening test in mice that hydroxybupropion is one-half as potent as bupropion, while threohydrobupropion and erythrohydrobupropion are 5-fold less potent than bupropion. This may be of clinical importance because the plasma concentrations of the metabolites are as high as or higher than those of bupropion. Bupropion and its metabolites exhibit linear kinetics following chronic administration of 300 to 450 mg per day. •Metabolism (Drug B): Hepatic. Two metabolic pathways have been suggested. The major pathway probably involves the direct oxidation of Nabilone to produce hydroxylic and carboxylic analogues. These compounds are thought to account for the remaining plasma radioactivity when carbinol metabolites have been extracted. •Route of elimination (Drug A): Bupropion is extensively metabolized in humans. Oxidation of the bupropion side chain results in the formation of a glycine conjugate of metachlorobenzoic acid, which is then excreted as the major urinary metabolite. Following oral administration of 200 mg of 14C-bupropion in humans, 87% and 10% of the radioactive dose were recovered in the urine and feces, respectively. However, the fraction of the oral dose of bupropion excreted unchanged was only 0.5%, a finding consistent with the extensive metabolism of bupropion. •Route of elimination (Drug B): The route and rate of the elimination of nabilone and its metabolites are similar to those observed with other cannabinoids, including delta-9-THC (dronabinol). When nabilone is administered intravenously, the drug and its metabolites are eliminated mainly in the feces (approximately 67%) and to a lesser extent in the urine (approximately 22%) within 7 days. Of the 67% recovered from the feces, 5% corresponded to the parent compound and 16% to its carbinol metabolite. Following oral administration about 60% of nabilone and its metabolites were recovered in the feces and about 24% in urine. Therefore, it appears that the major excretory pathway is the biliary system. •Half-life (Drug A): 24 hours •Half-life (Drug B): The plasma half-life (T1/2) values for nabilone and total radioactivity of identified and unidentified metabolites are about 2 and 35 hours, respectively. •Clearance (Drug A): No clearance available •Clearance (Drug B): No clearance available •Toxicity (Drug A): Symptoms of overdose include seizures, hallucinations, loss of consciousness, tachycardia, and cardiac arrest. •Toxicity (Drug B): Symptoms of overdose include difficulty in breathing, hallucinations, mental changes (severe), nervousness or anxiety (severe). Monkeys treated with Nabilone at doses as high as 2mg/kg/day for a year experienced no significant adverse events. This result contrasts with the finding in a planned 1-year dog study that was prematurely terminated because of deaths associated with convulsions in dogs receiving as little as 0.5mg/kg/day. The earliest deaths, however, occurred at 56 days in dogs receiving 2mg/kg/day. The unusual vulnerability of the dog is not understood; it is hypothesised, however, that the explanation lies in the fact that the dog differs markedly from other species (including humans) in its metabolism of Nabilone. •Brand Names (Drug A): Aplenzin, Auvelity, Budeprion, Contrave, Forfivo, Wellbutrin, Zyban •Brand Names (Drug B): Cesamet •Synonyms (Drug A): No synonyms listed •Synonyms (Drug B): No synonyms listed •Summary (Drug A): Bupropion is a norepinephrine and dopamine reuptake inhibitor used in the treatment of major depressive disorder (MDD), seasonal affective disorder (SAD), and as an aid to smoking cessation. •Summary (Drug B): Nabilone is a synthetic delta-9-THC used in the treatment of anorexia and weight loss in HIV patients as well as nausea and vomiting in cancer chemotherapy.

Nabilone has a CNS depressant effect, which may enhance the effects of central nervous system depressants. It may increase side effects such as dizziness, drowsiness, confusion, and difficulty concentrating, and may result in coma and death. The severity of the interaction is moderate.

Question: Does Bupropion and Nabilone interact? Information: •Drug A: Bupropion •Drug B: Nabilone •Severity: MODERATE •Description: Nabilone may increase the central nervous system depressant (CNS depressant) activities of Bupropion. •Extended Description: Nabilone has a CNS depressant effect, which may enhance the effects of central nervous system depressants. It may increase side effects such as dizziness, drowsiness, confusion, and difficulty concentrating, and may result in coma and death. •Indication (Drug A): Bupropion is indicated for the treatment of major depressive disorder (MDD), seasonal affective disorder (SAD), and as an aid to smoking cessation. When used in combination with naltrexone as the marketed product ContraveⓇ, bupropion is indicated as an adjunct to a reduced-calorie diet and increased physical activity for chronic weight management in adults with an initial body mass index (BMI) of: 30 kg/m^2 or greater (obese) or 27 kg/m^2 or greater (overweight) in the presence of at least one weight-related comorbid condition (e.g., hypertension, type 2 diabetes mellitus, or dyslipidemia). Bupropion is also used off-label as a first-line treatment in patients with ADHD and comorbid bipolar disorder when used as an adjunct to mood stabilizers. •Indication (Drug B): Nabilone is indicated for the treatment of the nausea and vomiting associated with cancer chemotherapy in patients who have failed to respond adequately to conventional antiemetic treatments. This restriction is required because a substantial proportion of any group of patients treated with Nabilone can be expected to experience disturbing psychotomimetic reactions not observed with other antiemetic agents. •Pharmacodynamics (Drug A): Bupropion is chemically unrelated to tricyclic, tetracyclic, selective serotonin re-uptake inhibitors, or other known antidepressant agents. Compared to classical tricyclic antidepressants, Bupropion is a relatively weak inhibitor of the neuronal uptake of norepinephrine and dopamine. In addition, Bupropion does not inhibit monoamine oxidase. Bupropion has been found to be essentially inactive at the serotonin transporter (SERT)(IC50 >10 000 nM), however both bupropion and its primary metabolite hydroxybupropion have been found to block the function of cation-selective serotonin type 3A receptors (5-HT3ARs). Bupropion produces dose-related central nervous system (CNS) stimulant effects in animals, as evidenced by increased locomotor activity, increased rates of responding in various schedule-controlled operant behaviour tasks, and, at high doses, induction of mild stereotyped behaviour. Due to these stimulant effects and selective activity at dopamine and norepinephrine receptors, bupropion has been identified as having an abuse potential. Bupropion has a similar structure to the controlled substance Cathinone, and has been identified as having mild amphetamine-like activity, particularly when inhaled or injected. Bupropion is also known to lower the seizure threshold, making any pre-existing seizure conditions a contraindication to its use. This risk is exacerbated when bupropion is combined with other drugs or substances that lower the seizure threshold, such as cocaine, or in clinical situations that would increase the risk of a seizure such as abrupt alcohol or benzodiazepine withdrawal. As norepinephrine has been shown to have anticonvulsant properties, bupropion's inhibitory effects on NET are thought to contribute to its pro-convulsant activity. Bupropion has been shown to increase blood pressure and pose a risk for exacerbation of unmanaged or pre-existing hypertension, however, clinical trials of bupropion in smokers with CVD have not identified an increased incidence of CV events including stroke or heart attack. In clinical trials, the mean increase in systolic blood pressure associated with the use of bupropion was found to be 1.3 mmHg. •Pharmacodynamics (Drug B): Nabilone is a cannabinoid with therapeutic uses. It is an analog of dronabinol (also known as tetrahydrocannabinol or THC), the psychoactive ingredient in cannabis. Although structurally distinct from THC, nabilone mimics THC's structure and pharmacological activity through weak partial agonist activity at Cannabinoid-1 (CB1R) and Cannabinoid-2 (CB2R) receptors, however it is considered to be twice as active as Δ⁹-THC. •Mechanism of action (Drug A): Bupropion is a norepinephrine/dopamine-reuptake inhibitor (NDRI) that exerts its pharmacological effects by weakly inhibiting the enzymes involved in the uptake of the neurotransmitters norepinephrine and dopamine from the synaptic cleft, therefore prolonging their duration of action within the neuronal synapse and the downstream effects of these neurotransmitters. More specifically, bupropion binds to the norepinephrine transporter (NET) and the dopamine transporter (DAT). Bupropion was originally classified as an "atypical" antidepressant because it does not exert the same effects as the classical antidepressants such as Monoamine Oxidase Inhibitors (MAOIs), Tricyclic Antidepressants (TCAs), or Selective Serotonin Reuptake Inhibitors (SSRIs). While it has comparable effectiveness to typical first-line options for the treatment of depression such as SSRIs, bupropion is a unique option for the treatment of MDD as it lacks any clinically relevant serotonergic effects, typical of other mood medications, or any effects on histamine or adrenaline receptors. Lack of activity at these receptors results in a more tolerable side effect profile; bupropion is less likely to cause sexual side effects, sedation, or weight gain as compared to SSRIs or TCAs, for example. When used as an aid to smoking cessation, bupropion is thought to confer its anti-craving and anti-withdrawal effects by inhibiting dopamine reuptake, which is thought to be involved in the reward pathways associated with nicotine, and through the antagonism of the nicotinic acetylcholinergic receptor (AChR), thereby blunting the effects of nicotine. Furthermore, the stimulatory effects produced by bupropion in the central nervous system are similar to nicotine's effects, making low doses of bupropion a suitable option as a nicotine substitute. When used in combination with naltrexone in the marketed product ContraveⓇ for chronic weight management, the two components are thought to have effects on areas of the brain involved in the regulation of food intake. This includes the hypothalamus, which is involved in appetite regulation, and the mesolimbic dopamine circuit, which is involved in reward pathways. Studies have shown that the combined activity of bupropion and naltrexone increase the firing rate of hypothalamic pro-opiomelanocortin (POMC) neurons and blockade of opioid receptor-mediated POMC auto-inhibition, which are associated with a reduction in food intake and increased energy expenditure. This combination was also found to reduce food intake when injected directly into the ventral tegmental area of the mesolimbic circuit in mice, which is an area associated with the regulation of reward pathways. •Mechanism of action (Drug B): Nabilone is an orally active synthetic cannabinoid which, like other cannabinoids, has complex effects on the central nervous system (CNS). It has been suggested that the antiemetic effect of nabilone is caused by interaction with the cannabinoid receptor system, i.e., the CB (1) receptor, which is a component of the endocannabinoid system of the body. The endocannabinoid system is widely distributed throughout the central and peripheral nervous system (via the Cannabinoid Receptors CB1 and CB2) and plays a role in many physiological processes such as inflammation, cardiovascular function, learning, pain, memory, stress and emotional regulation, and the sleep/wake cycle among many others. CB1 receptors are found in both the central and peripheral nervous system, and are most abundant in the hippocampus and amygdala, which are the areas of the brain responsible for short-term memory storage and emotional regulation. CB2 receptors are mainly located in the peripheral nervous system and can be found on lymphoid tissue where they are involved in regulation of immune function. •Absorption (Drug A): Bupropion is currently available in 3 distinct, but bioequivalent formulations: immediate release (IR), sustained-release (SR), and extended-release (XL). Immediate Release Formulation In humans, following oral administration of bupropion hydrochloride tablets, peak plasma bupropion concentrations are usually achieved within 2 hours. IR formulations provide a short duration of action and are therefore generally dosed three times per day. Sustained Release Formulation In humans, following oral administration of bupropion hydrochloride sustained-release tablets (SR), peak plasma concentration (Cmax) of bupropion is usually achieved within 3 hours. SR formulations provide a 12-hour extended release of medication and are therefore generally dosed twice per day. Extended Release Formulation Following single oral administration of bupropion hydrochloride extended-release tablets (XL) to healthy volunteers, the median time to peak plasma concentrations for bupropion was approximately 5 hours. The presence of food did not affect the peak concentration or area under the curve of bupropion. XL formulations provide a 24-hour extended release of medication and are therefore generally dosed once per day/ In a trial comparing chronic dosing with bupropion hydrochloride extended-release tablets (SR) 150 mg twice daily to bupropion immediate-release formulation 100 mg 3 times daily, the steady state Cmax for bupropion after bupropion hydrochloride sustained-release tablets (SR) administration was approximately 85% of those achieved after bupropion immediate-release formulation administration. Exposure (AUC) to bupropion was equivalent for both formulations. Bioequivalence was also demonstrated for all three major active metabolites (i.e., hydroxybupropion, threohydrobupropion and erythrohydrobupropion) for both Cmax and AUC. Thus, at steady state, bupropion hydrochloride sustained-release tablets (SR) given twice daily, and the immediate-release formulation of bupropion given 3 times daily, are essentially bioequivalent for both bupropion and the 3 quantitatively important metabolites. Furthermore, in a study comparing 14-day dosing with bupropion hydrochloride extended-release tablets (XL), 300 mg once-daily to the immediate-release formulation of bupropion at 100 mg 3 times daily, equivalence was demonstrated for peak plasma concentration and area under the curve for bupropion and the three metabolites (hydroxybupropion, threohydrobupropion, and erythrohydrobupropion). Additionally, in a study comparing 14-day dosing with bupropion hydrochloride extended-release tablets (XL) 300 mg once daily to the sustained-release formulation of bupropion at 150 mg 2 times daily, equivalence was demonstrated for peak plasma concentration and area under the curve for bupropion and the three metabolites. Bupropion hydrochloride extended-release tablets (SR) can be taken with or without food. Bupropion Cmax and AUC were increased by 11% to 35% and 16% to 19%, respectively, when bupropion hydrochloride extended-release tablets (SR) was administered with food to healthy volunteers in three trials. The food effect is not considered clinically significant. Following a single-dose administration of bupropion hydrochloride extended-release tablets (SR) in humans, Cmax of bupropion's metabolite hydroxybupropion occurs approximately 6 hours post-dose and is approximately 10 times the peak level of the parent drug at steady state. The elimination half-life of hydroxybupropion is approximately 20 (±5) hours and its AUC at steady state is about 17 times that of bupropion. The times to peak concentrations for the erythrohydrobupropion and threohydrobupropion metabolites are similar to that of the hydroxybupropion metabolite. However, their elimination half-lives are longer, 33(±10) and 37 (±13) hours, respectively, and steady-state AUCs are 1.5 and 7 times that of bupropion, respectively. •Absorption (Drug B): Nabilone appears to be completely absorbed from the human gastrointestinal tract when administered orally. Following oral administration of a 2 mg dose of radiolabeled nabilone, peak plasma concentrations of approximately 2 ng/mL nabilone and 10 ng equivalents/mL total radioactivity are achieved within 2.0 hours. •Volume of distribution (Drug A): No volume of distribution available •Volume of distribution (Drug B): The apparent volume of distribution of nabilone is about 12.5 L/kg. •Protein binding (Drug A): In vitro tests show that bupropion is 84% bound to human plasma proteins at concentrations up to 200 mcg per mL. The extent of protein binding of the hydroxybupropion metabolite is similar to that for bupropion, whereas the extent of protein binding of the threohydrobupropion metabolite is about half that seen with bupropion. •Protein binding (Drug B): No protein binding available •Metabolism (Drug A): Bupropion is extensively metabolized in humans. Three metabolites are active: hydroxybupropion, which is formed via hydroxylation of the tert-butyl group of bupropion, and the amino-alcohol isomers, threohydrobupropion and erythrohydrobupropion, which are formed via reduction of the carbonyl group. In vitro findings suggest that CYP2B6 is the principal isoenzyme involved in the formation of hydroxybupropion, while cytochrome P450 enzymes are not involved in the formation of threohydrobupropion. Hydroxybupropion has been shown to have the same affinity as bupropion for the norepinephrine transporter (NET) but approximately 50% of its antidepressant activity despite reaching concentrations of ~10-fold higher than that of the parent drug. Oxidation of the bupropion side chain results in the formation of a glycine conjugate of meta-chlorobenzoic acid, which is then excreted as the major urinary metabolite. The potency and toxicity of the metabolites relative to bupropion have not been fully characterized. However, it has been demonstrated in an antidepressant screening test in mice that hydroxybupropion is one-half as potent as bupropion, while threohydrobupropion and erythrohydrobupropion are 5-fold less potent than bupropion. This may be of clinical importance because the plasma concentrations of the metabolites are as high as or higher than those of bupropion. Bupropion and its metabolites exhibit linear kinetics following chronic administration of 300 to 450 mg per day. •Metabolism (Drug B): Hepatic. Two metabolic pathways have been suggested. The major pathway probably involves the direct oxidation of Nabilone to produce hydroxylic and carboxylic analogues. These compounds are thought to account for the remaining plasma radioactivity when carbinol metabolites have been extracted. •Route of elimination (Drug A): Bupropion is extensively metabolized in humans. Oxidation of the bupropion side chain results in the formation of a glycine conjugate of metachlorobenzoic acid, which is then excreted as the major urinary metabolite. Following oral administration of 200 mg of 14C-bupropion in humans, 87% and 10% of the radioactive dose were recovered in the urine and feces, respectively. However, the fraction of the oral dose of bupropion excreted unchanged was only 0.5%, a finding consistent with the extensive metabolism of bupropion. •Route of elimination (Drug B): The route and rate of the elimination of nabilone and its metabolites are similar to those observed with other cannabinoids, including delta-9-THC (dronabinol). When nabilone is administered intravenously, the drug and its metabolites are eliminated mainly in the feces (approximately 67%) and to a lesser extent in the urine (approximately 22%) within 7 days. Of the 67% recovered from the feces, 5% corresponded to the parent compound and 16% to its carbinol metabolite. Following oral administration about 60% of nabilone and its metabolites were recovered in the feces and about 24% in urine. Therefore, it appears that the major excretory pathway is the biliary system. •Half-life (Drug A): 24 hours •Half-life (Drug B): The plasma half-life (T1/2) values for nabilone and total radioactivity of identified and unidentified metabolites are about 2 and 35 hours, respectively. •Clearance (Drug A): No clearance available •Clearance (Drug B): No clearance available •Toxicity (Drug A): Symptoms of overdose include seizures, hallucinations, loss of consciousness, tachycardia, and cardiac arrest. •Toxicity (Drug B): Symptoms of overdose include difficulty in breathing, hallucinations, mental changes (severe), nervousness or anxiety (severe). Monkeys treated with Nabilone at doses as high as 2mg/kg/day for a year experienced no significant adverse events. This result contrasts with the finding in a planned 1-year dog study that was prematurely terminated because of deaths associated with convulsions in dogs receiving as little as 0.5mg/kg/day. The earliest deaths, however, occurred at 56 days in dogs receiving 2mg/kg/day. The unusual vulnerability of the dog is not understood; it is hypothesised, however, that the explanation lies in the fact that the dog differs markedly from other species (including humans) in its metabolism of Nabilone. •Brand Names (Drug A): Aplenzin, Auvelity, Budeprion, Contrave, Forfivo, Wellbutrin, Zyban •Brand Names (Drug B): Cesamet •Synonyms (Drug A): No synonyms listed •Synonyms (Drug B): No synonyms listed •Summary (Drug A): Bupropion is a norepinephrine and dopamine reuptake inhibitor used in the treatment of major depressive disorder (MDD), seasonal affective disorder (SAD), and as an aid to smoking cessation. •Summary (Drug B): Nabilone is a synthetic delta-9-THC used in the treatment of anorexia and weight loss in HIV patients as well as nausea and vomiting in cancer chemotherapy. Output: Nabilone has a CNS depressant effect, which may enhance the effects of central nervous system depressants. It may increase side effects such as dizziness, drowsiness, confusion, and difficulty concentrating, and may result in coma and death. The severity of the interaction is moderate.

Does Bupropion and Nabumetone interact?

•Drug A: Bupropion •Drug B: Nabumetone •Severity: MINOR •Description: Nabumetone may decrease the excretion rate of Bupropion which could result in a higher serum level. •Extended Description: The subject drug is a nephrotoxic agent that may potentially impair renal function and decrease the excretion of drugs that mainly undergo renal excretion as the principal mode of clearance, such as the affected drug. Attenuated renal excretion of the affected drug may increase drug concentrations, leading to an elevated risk for drug-related adverse effects. •Indication (Drug A): Bupropion is indicated for the treatment of major depressive disorder (MDD), seasonal affective disorder (SAD), and as an aid to smoking cessation. When used in combination with naltrexone as the marketed product ContraveⓇ, bupropion is indicated as an adjunct to a reduced-calorie diet and increased physical activity for chronic weight management in adults with an initial body mass index (BMI) of: 30 kg/m^2 or greater (obese) or 27 kg/m^2 or greater (overweight) in the presence of at least one weight-related comorbid condition (e.g., hypertension, type 2 diabetes mellitus, or dyslipidemia). Bupropion is also used off-label as a first-line treatment in patients with ADHD and comorbid bipolar disorder when used as an adjunct to mood stabilizers. •Indication (Drug B): Indicated for: 1) Symptomatic relief in rheumatoid arthritis. 2) Symptomatic relief in osteoarthritis. •Pharmacodynamics (Drug A): Bupropion is chemically unrelated to tricyclic, tetracyclic, selective serotonin re-uptake inhibitors, or other known antidepressant agents. Compared to classical tricyclic antidepressants, Bupropion is a relatively weak inhibitor of the neuronal uptake of norepinephrine and dopamine. In addition, Bupropion does not inhibit monoamine oxidase. Bupropion has been found to be essentially inactive at the serotonin transporter (SERT)(IC50 >10 000 nM), however both bupropion and its primary metabolite hydroxybupropion have been found to block the function of cation-selective serotonin type 3A receptors (5-HT3ARs). Bupropion produces dose-related central nervous system (CNS) stimulant effects in animals, as evidenced by increased locomotor activity, increased rates of responding in various schedule-controlled operant behaviour tasks, and, at high doses, induction of mild stereotyped behaviour. Due to these stimulant effects and selective activity at dopamine and norepinephrine receptors, bupropion has been identified as having an abuse potential. Bupropion has a similar structure to the controlled substance Cathinone, and has been identified as having mild amphetamine-like activity, particularly when inhaled or injected. Bupropion is also known to lower the seizure threshold, making any pre-existing seizure conditions a contraindication to its use. This risk is exacerbated when bupropion is combined with other drugs or substances that lower the seizure threshold, such as cocaine, or in clinical situations that would increase the risk of a seizure such as abrupt alcohol or benzodiazepine withdrawal. As norepinephrine has been shown to have anticonvulsant properties, bupropion's inhibitory effects on NET are thought to contribute to its pro-convulsant activity. Bupropion has been shown to increase blood pressure and pose a risk for exacerbation of unmanaged or pre-existing hypertension, however, clinical trials of bupropion in smokers with CVD have not identified an increased incidence of CV events including stroke or heart attack. In clinical trials, the mean increase in systolic blood pressure associated with the use of bupropion was found to be 1.3 mmHg. •Pharmacodynamics (Drug B): NSAIDs, like nabumetone, are well established as analgesics. NSAIDs reduce both peripheral and central sensitization of nociceptive neurons due to inflammation which contribute to hyperalgesia and allodynia. This sensitization occurs through reducing the action potential threshold in peripheral neurons, reducing the intensity of painful stimuli needed to produce a painful sensation. Centrally, activation of dorsal horn neurons occurs along with increased release of glutamate, calcitonin gene-related peptide (CGRP), and substance P which increase the transmission of painful stimuli. Coupled with this is an inhibition glycinergic neurons which normally inhibit pain transmission, a phenomenon known as disinhibition. Increased activity ofn-methyl d-aspartate (NMDA) and α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid (AMPA) receptors leads to the establishment of central sensitization, allowing both mild painful and innocuous stimuli to produce action potentials in nociceptive projection neurons. NSAIDs are effective in reducing mild-moderate acute and chronic nociceptive pain, however, the usefulness of NSAIDs in neuropathic pain is limited. The anti-inflammatory effect of NSAIDs is mediated by preventing vasodilation, increases in vascular permeability, and the release of cytokines from endothelial cells. These three effects together prevent immunocompetent cells from migrating to the site of injury thereby preventing additional damage and inflammation due to activation of the immune system at the site of damage. PGs also modulate T-helper cell activation and differentiation, an activity which is thought to be of importance in arthritic conditions. The anti-pyretic effect of NSAIDs is mediated through preventing increases in temperature by prostaglandins (PGs) via the hypothalamus. Activation of this process by other inflammatory mediators relies upon subsequent action by PGs, therefore NSAIDs are able to reduce fever due to these mediators as well. The adverse effects of NSAIDs are related to their therapeutic effects. The same vasodilatory action which occurs in inflammation also serves to regulate blood flow to the kidneys through the afferent renal arteries. NSAIDs are widely known as nephrotoxic agents as the reduction in PGs produces vasoconstriction of these arteries resulting in reduced blood flow to the kidneys and a subsequent decline in renal function. Reductions in mucus and HCO 3 secretion in the stomach increases the risk of ulceration by limiting the protection mediated by PGs. Lastly, COX-2 selective agents like nabumetone can unbalance prothrombotic and antithrombotic prostanoid generation leading to increased platelet aggregation and increased risk of thrombosis. •Mechanism of action (Drug A): Bupropion is a norepinephrine/dopamine-reuptake inhibitor (NDRI) that exerts its pharmacological effects by weakly inhibiting the enzymes involved in the uptake of the neurotransmitters norepinephrine and dopamine from the synaptic cleft, therefore prolonging their duration of action within the neuronal synapse and the downstream effects of these neurotransmitters. More specifically, bupropion binds to the norepinephrine transporter (NET) and the dopamine transporter (DAT). Bupropion was originally classified as an "atypical" antidepressant because it does not exert the same effects as the classical antidepressants such as Monoamine Oxidase Inhibitors (MAOIs), Tricyclic Antidepressants (TCAs), or Selective Serotonin Reuptake Inhibitors (SSRIs). While it has comparable effectiveness to typical first-line options for the treatment of depression such as SSRIs, bupropion is a unique option for the treatment of MDD as it lacks any clinically relevant serotonergic effects, typical of other mood medications, or any effects on histamine or adrenaline receptors. Lack of activity at these receptors results in a more tolerable side effect profile; bupropion is less likely to cause sexual side effects, sedation, or weight gain as compared to SSRIs or TCAs, for example. When used as an aid to smoking cessation, bupropion is thought to confer its anti-craving and anti-withdrawal effects by inhibiting dopamine reuptake, which is thought to be involved in the reward pathways associated with nicotine, and through the antagonism of the nicotinic acetylcholinergic receptor (AChR), thereby blunting the effects of nicotine. Furthermore, the stimulatory effects produced by bupropion in the central nervous system are similar to nicotine's effects, making low doses of bupropion a suitable option as a nicotine substitute. When used in combination with naltrexone in the marketed product ContraveⓇ for chronic weight management, the two components are thought to have effects on areas of the brain involved in the regulation of food intake. This includes the hypothalamus, which is involved in appetite regulation, and the mesolimbic dopamine circuit, which is involved in reward pathways. Studies have shown that the combined activity of bupropion and naltrexone increase the firing rate of hypothalamic pro-opiomelanocortin (POMC) neurons and blockade of opioid receptor-mediated POMC auto-inhibition, which are associated with a reduction in food intake and increased energy expenditure. This combination was also found to reduce food intake when injected directly into the ventral tegmental area of the mesolimbic circuit in mice, which is an area associated with the regulation of reward pathways. •Mechanism of action (Drug B): Nabumetone's active metabolite, 6-MNA, is an inhibitor of both COX-1 and COX-2 although it exhibits some COX-2 selectivity. Inhibition of COX-1 and COX-2 reduces conversion of arachidonic acid to PGs and thromboxane (TXA 2 ). This reduction in prostanoid production is the common mechanism that mediates the effects of nambutone. PGE 2 is the primary PG involved in modulation of nociception. It mediates peripheral sensitization through a variety of effects. PGE 2 activates the G q -coupled EP 1 receptor leading to increased activity of the inositol trisphosphate/phospholipase C pathway. Activation of this pathway releases intracellular stores of calcium which directly reduces action potential threshold and activates protein kinase C (PKC) which contributes to several indirect mechanisms. PGE 2 also activates the EP 4 receptor, coupled to G s, which activates the adenylyl cyclase/protein kinase A (AC/PKA) signaling pathway. PKA and PKC both contribute to the potentiation of transient receptor potential cation channel subfamily V member 1 (TRPV1) potentiation, which increases sensitivity to heat stimuli. They also activate tetrodotoxin-resistant sodium channels and inhibit inward potassium currents. PKA further contributes to the activation of the P2X3 purine receptor and sensitization of T-type calcium channels. The activation and sensitization of depolarizing ion channels and inhibition of inward potassium currents serve to reduce the intensity of stimulus necessary to generate action potentials in nociceptive sensory afferents. PGE 2 act via EP 3 to increase sensitivity to bradykinin and via EP 2 to further increase heat sensitivity. Central sensitization occurs in the dorsal horn of the spinal cord and is mediated by the EP 2 receptor which couples to G s. Pre-synaptically, this receptor increases the release of pro-nociceptive neurotransmitters glutamate, CGRP, and substance P. Post-synaptically it increases the activity of AMPA and NMDA receptors and produces inhibition of inhibitory glycinergic neurons. Together these lead to a reduced threshold of activating, allowing low intensity stimuli to generate pain signals. PGI 2 is known to play a role via its G s -coupled IP receptor although the magnitude of its contribution varies. It has been proposed to be of greater importance in painful inflammatory conditions such as arthritis. By limiting sensitization, both peripheral and central, via these pathways NSAIDs can effectively reduce inflammatory pain. PGI 2 and PGE 2 contribute to acute inflammation via their IP and EP 2 receptors. Similarly to β adrenergic receptors these are G s -coupled and mediate vasodilation through the AC/PKA pathway. PGE 2 also contributes by increasing leukocyte adhesion to the endothelium and attracts the cells to the site of injury. PGD 2 plays a role in the activation of endothelial cell release of cytokines through its DP 1 receptor. PGI 2 and PGE 2 modulate T-helper cell activation and differentiation through IP, EP 2, and EP 4 receptors which is believed to be an important activity in the pathology of arthritic conditions. By limiting the production of these PGs at the site of injury, NSAIDs can reduce inflammation. PGE 2 can cross the blood-brain barrier and act on excitatory G q EP 3 receptors on thermoregulatory neurons in the hypothalamus. This activation triggers an increase in heat-generation and a reduction in heat-loss to produce a fever. NSAIDs prevent the generation of PGE 2 thereby reducing the activity of these neurons. The adverse effects of NSAIDs stem from the protective and regulatory roles of prostanoids which have been well-characterized. PGI 2 and PGE 2 regulate blood flow to the kidney by similar mechanisms to the vasodilation they produce in inflammation. Prevention of this regulation by NSAIDs produces vasoconstriction which limits renal function by reducing blood flow and the hydrostatic pressure which drives filtration. PGE 2 also regulates gastric protection via EP 3 receptors which are, in this location, coupled to G i which inhibits the AC/PKA pathway. This reduces the secretion of protons by H /K ATPase in parietal cells and increases the secretion of mucus and HCO 3 by superficial endothelial cells. Disruption of this protective action by NSAIDs lead to ulceration of the gastric mucosa. Lastly, disruption of PGI 2, which opposes platelet aggregation, generation by COX-2 selective agents leads to an imbalance with TXA 2 generated by COX-1, which promotes aggregation of platelets, leading to increased risk of thrombosis. Since nabumetone is somewhat COX-2 selective it is thought to promote this imbalance and increase thrombotic risk. •Absorption (Drug A): Bupropion is currently available in 3 distinct, but bioequivalent formulations: immediate release (IR), sustained-release (SR), and extended-release (XL). Immediate Release Formulation In humans, following oral administration of bupropion hydrochloride tablets, peak plasma bupropion concentrations are usually achieved within 2 hours. IR formulations provide a short duration of action and are therefore generally dosed three times per day. Sustained Release Formulation In humans, following oral administration of bupropion hydrochloride sustained-release tablets (SR), peak plasma concentration (Cmax) of bupropion is usually achieved within 3 hours. SR formulations provide a 12-hour extended release of medication and are therefore generally dosed twice per day. Extended Release Formulation Following single oral administration of bupropion hydrochloride extended-release tablets (XL) to healthy volunteers, the median time to peak plasma concentrations for bupropion was approximately 5 hours. The presence of food did not affect the peak concentration or area under the curve of bupropion. XL formulations provide a 24-hour extended release of medication and are therefore generally dosed once per day/ In a trial comparing chronic dosing with bupropion hydrochloride extended-release tablets (SR) 150 mg twice daily to bupropion immediate-release formulation 100 mg 3 times daily, the steady state Cmax for bupropion after bupropion hydrochloride sustained-release tablets (SR) administration was approximately 85% of those achieved after bupropion immediate-release formulation administration. Exposure (AUC) to bupropion was equivalent for both formulations. Bioequivalence was also demonstrated for all three major active metabolites (i.e., hydroxybupropion, threohydrobupropion and erythrohydrobupropion) for both Cmax and AUC. Thus, at steady state, bupropion hydrochloride sustained-release tablets (SR) given twice daily, and the immediate-release formulation of bupropion given 3 times daily, are essentially bioequivalent for both bupropion and the 3 quantitatively important metabolites. Furthermore, in a study comparing 14-day dosing with bupropion hydrochloride extended-release tablets (XL), 300 mg once-daily to the immediate-release formulation of bupropion at 100 mg 3 times daily, equivalence was demonstrated for peak plasma concentration and area under the curve for bupropion and the three metabolites (hydroxybupropion, threohydrobupropion, and erythrohydrobupropion). Additionally, in a study comparing 14-day dosing with bupropion hydrochloride extended-release tablets (XL) 300 mg once daily to the sustained-release formulation of bupropion at 150 mg 2 times daily, equivalence was demonstrated for peak plasma concentration and area under the curve for bupropion and the three metabolites. Bupropion hydrochloride extended-release tablets (SR) can be taken with or without food. Bupropion Cmax and AUC were increased by 11% to 35% and 16% to 19%, respectively, when bupropion hydrochloride extended-release tablets (SR) was administered with food to healthy volunteers in three trials. The food effect is not considered clinically significant. Following a single-dose administration of bupropion hydrochloride extended-release tablets (SR) in humans, Cmax of bupropion's metabolite hydroxybupropion occurs approximately 6 hours post-dose and is approximately 10 times the peak level of the parent drug at steady state. The elimination half-life of hydroxybupropion is approximately 20 (±5) hours and its AUC at steady state is about 17 times that of bupropion. The times to peak concentrations for the erythrohydrobupropion and threohydrobupropion metabolites are similar to that of the hydroxybupropion metabolite. However, their elimination half-lives are longer, 33(±10) and 37 (±13) hours, respectively, and steady-state AUCs are 1.5 and 7 times that of bupropion, respectively. •Absorption (Drug B): Nabumetone is well-absorbed from the GI tract and undergoes significant first pass metabolism resulting in approximately 35% being converted to the active metabolite, 6-MNA. Tmax for 6-MNA varies widely with a mean values of 3 and 11 hours reported in official product monographs, and described as 9-12 hours in published literature Administration with food increases Cmax by 33% and increases absorption rate. If formulated as a suspension the Cmax increases and the Tmax is reduced by 0.8 hours while the all other pharmacokinetic parameters remain unchanged. •Volume of distribution (Drug A): No volume of distribution available •Volume of distribution (Drug B): The Vd of 6-MNA reported after administration of a single dose is 0.1-0.2 L/kg or approximately 5-10 L. Vdss reported in official product labeling is approximately 53 L. •Protein binding (Drug A): In vitro tests show that bupropion is 84% bound to human plasma proteins at concentrations up to 200 mcg per mL. The extent of protein binding of the hydroxybupropion metabolite is similar to that for bupropion, whereas the extent of protein binding of the threohydrobupropion metabolite is about half that seen with bupropion. •Protein binding (Drug B): 6-MNA is over 99% bound to plasma proteins, likely albumin. The unbound fraction is 0.1-0.2% and remains proportional in the dose range of 1000-2000mg •Metabolism (Drug A): Bupropion is extensively metabolized in humans. Three metabolites are active: hydroxybupropion, which is formed via hydroxylation of the tert-butyl group of bupropion, and the amino-alcohol isomers, threohydrobupropion and erythrohydrobupropion, which are formed via reduction of the carbonyl group. In vitro findings suggest that CYP2B6 is the principal isoenzyme involved in the formation of hydroxybupropion, while cytochrome P450 enzymes are not involved in the formation of threohydrobupropion. Hydroxybupropion has been shown to have the same affinity as bupropion for the norepinephrine transporter (NET) but approximately 50% of its antidepressant activity despite reaching concentrations of ~10-fold higher than that of the parent drug. Oxidation of the bupropion side chain results in the formation of a glycine conjugate of meta-chlorobenzoic acid, which is then excreted as the major urinary metabolite. The potency and toxicity of the metabolites relative to bupropion have not been fully characterized. However, it has been demonstrated in an antidepressant screening test in mice that hydroxybupropion is one-half as potent as bupropion, while threohydrobupropion and erythrohydrobupropion are 5-fold less potent than bupropion. This may be of clinical importance because the plasma concentrations of the metabolites are as high as or higher than those of bupropion. Bupropion and its metabolites exhibit linear kinetics following chronic administration of 300 to 450 mg per day. •Metabolism (Drug B): Nabumetone is reduced to 3-hydroxy nabumetone by the aldo-keto reductase-1C family and by corticosteroid 11-beta-dehydrogenase. It then undergoes oxidative cleavage by CYP1A2 to 6-MNA, the active metabolite. 6-MNA is eliminated by O-demethylation by CYP2C9 to 6-hydroxy-2-naphthylacetic acid (6-HNA). Both 6-MNA and 6-HNA are further converted to conjugates. Other metabolites are generated through a mix of ketone reduction and O-demethylation along with subsequent conjugation. Glucuronide conjugates of several metabolites have been found to become further conjugated to glycine residues. •Route of elimination (Drug A): Bupropion is extensively metabolized in humans. Oxidation of the bupropion side chain results in the formation of a glycine conjugate of metachlorobenzoic acid, which is then excreted as the major urinary metabolite. Following oral administration of 200 mg of 14C-bupropion in humans, 87% and 10% of the radioactive dose were recovered in the urine and feces, respectively. However, the fraction of the oral dose of bupropion excreted unchanged was only 0.5%, a finding consistent with the extensive metabolism of bupropion. •Route of elimination (Drug B): Most drug is eliminated via hepatic metabolism with minimal to no parent drug detectable in the plasma. 80% of the dose is then excreted by the kidneys and 10% in the feces. It does not appear to undergo enterohepatic recirculation. •Half-life (Drug A): 24 hours •Half-life (Drug B): 6-MNA has a mean half-life of 24 hours with a range of 19-36 hours. •Clearance (Drug A): No clearance available •Clearance (Drug B): 6-MNA has an apparent steady-state clearance of 20 - 30 mL/min. •Toxicity (Drug A): Symptoms of overdose include seizures, hallucinations, loss of consciousness, tachycardia, and cardiac arrest. •Toxicity (Drug B): LD 50 Values Mouse: 4290 mg/kg (Oral), 2380 mg/kg (IP) Rat: 3880 mg/kg (Oral), 1520 mg/kg (IP), >10 g/kg (SC) Monkey: 3200 mg/kg (Oral) Overdose Signs and symptoms of nabumetone overdose include lethargy, drowsiness, nausea, vomiting, and epigastric pain. These are considered reversible with supportive care. GI bleeding, hypertension, acute kidney injury, respiratory depression, and coma are rare but can occur. No antidote exists for nabumetone overdose although administration of activated charcoal and/or induction of emesis can reduce absorption if the nabumetone dose was taken less than 4 hours prior. 6-MNA is cannot be cleared by dialysis. Carcinogenicity & Mutagenicity Nabumetone was not significantly carcinogenic in rats or mice studied over 2 years. Neither the Ames test nor mouse micronucleus test showed nabumetone or it's active metabolite, 6-MNA, to be mutagenic. Chromosomal abberation has been observed in cultured lymphocytes exposed to concentrations of 80 mcg/mL and higher of nabumetone or 6-MNA equivalent to the maximum recommended human dose. Reproductive Toxicity No adverse effects on fertility have been observed in male and female rats at doses of 320 mg/kg/day. ] No teratogenicity has been observed in pregnant rabbits or rats. Dystocia and delayed parturition have been noted in rats resulting in reduced survival of offspring. This has been attributed to the role of prostaglandins in uterine contraction. NSAIDs can also cause premature closure of the ductus ateriosus. Lactation 6-MNA has been detected in the milk of lactating rats. While no data is available in humans, 6-MNA is both highly protein bound and exists in its anionic form in circulation. For these reasons partitioning into breast milk is expected to be limited. •Brand Names (Drug A): Aplenzin, Auvelity, Budeprion, Contrave, Forfivo, Wellbutrin, Zyban •Brand Names (Drug B): Relafen •Synonyms (Drug A): No synonyms listed •Synonyms (Drug B): Nabumeton Nabumetona Nabumétone Nabumetone Nabumetonum •Summary (Drug A): Bupropion is a norepinephrine and dopamine reuptake inhibitor used in the treatment of major depressive disorder (MDD), seasonal affective disorder (SAD), and as an aid to smoking cessation. •Summary (Drug B): Nabumetone is an NSAID used to treat osteoarthritis and rheumatoid arthritis.

The subject drug is a nephrotoxic agent that may potentially impair renal function and decrease the excretion of drugs that mainly undergo renal excretion as the principal mode of clearance, such as the affected drug. Attenuated renal excretion of the affected drug may increase drug concentrations, leading to an elevated risk for drug-related adverse effects. The severity of the interaction is minor.

Question: Does Bupropion and Nabumetone interact? Information: •Drug A: Bupropion •Drug B: Nabumetone •Severity: MINOR •Description: Nabumetone may decrease the excretion rate of Bupropion which could result in a higher serum level. •Extended Description: The subject drug is a nephrotoxic agent that may potentially impair renal function and decrease the excretion of drugs that mainly undergo renal excretion as the principal mode of clearance, such as the affected drug. Attenuated renal excretion of the affected drug may increase drug concentrations, leading to an elevated risk for drug-related adverse effects. •Indication (Drug A): Bupropion is indicated for the treatment of major depressive disorder (MDD), seasonal affective disorder (SAD), and as an aid to smoking cessation. When used in combination with naltrexone as the marketed product ContraveⓇ, bupropion is indicated as an adjunct to a reduced-calorie diet and increased physical activity for chronic weight management in adults with an initial body mass index (BMI) of: 30 kg/m^2 or greater (obese) or 27 kg/m^2 or greater (overweight) in the presence of at least one weight-related comorbid condition (e.g., hypertension, type 2 diabetes mellitus, or dyslipidemia). Bupropion is also used off-label as a first-line treatment in patients with ADHD and comorbid bipolar disorder when used as an adjunct to mood stabilizers. •Indication (Drug B): Indicated for: 1) Symptomatic relief in rheumatoid arthritis. 2) Symptomatic relief in osteoarthritis. •Pharmacodynamics (Drug A): Bupropion is chemically unrelated to tricyclic, tetracyclic, selective serotonin re-uptake inhibitors, or other known antidepressant agents. Compared to classical tricyclic antidepressants, Bupropion is a relatively weak inhibitor of the neuronal uptake of norepinephrine and dopamine. In addition, Bupropion does not inhibit monoamine oxidase. Bupropion has been found to be essentially inactive at the serotonin transporter (SERT)(IC50 >10 000 nM), however both bupropion and its primary metabolite hydroxybupropion have been found to block the function of cation-selective serotonin type 3A receptors (5-HT3ARs). Bupropion produces dose-related central nervous system (CNS) stimulant effects in animals, as evidenced by increased locomotor activity, increased rates of responding in various schedule-controlled operant behaviour tasks, and, at high doses, induction of mild stereotyped behaviour. Due to these stimulant effects and selective activity at dopamine and norepinephrine receptors, bupropion has been identified as having an abuse potential. Bupropion has a similar structure to the controlled substance Cathinone, and has been identified as having mild amphetamine-like activity, particularly when inhaled or injected. Bupropion is also known to lower the seizure threshold, making any pre-existing seizure conditions a contraindication to its use. This risk is exacerbated when bupropion is combined with other drugs or substances that lower the seizure threshold, such as cocaine, or in clinical situations that would increase the risk of a seizure such as abrupt alcohol or benzodiazepine withdrawal. As norepinephrine has been shown to have anticonvulsant properties, bupropion's inhibitory effects on NET are thought to contribute to its pro-convulsant activity. Bupropion has been shown to increase blood pressure and pose a risk for exacerbation of unmanaged or pre-existing hypertension, however, clinical trials of bupropion in smokers with CVD have not identified an increased incidence of CV events including stroke or heart attack. In clinical trials, the mean increase in systolic blood pressure associated with the use of bupropion was found to be 1.3 mmHg. •Pharmacodynamics (Drug B): NSAIDs, like nabumetone, are well established as analgesics. NSAIDs reduce both peripheral and central sensitization of nociceptive neurons due to inflammation which contribute to hyperalgesia and allodynia. This sensitization occurs through reducing the action potential threshold in peripheral neurons, reducing the intensity of painful stimuli needed to produce a painful sensation. Centrally, activation of dorsal horn neurons occurs along with increased release of glutamate, calcitonin gene-related peptide (CGRP), and substance P which increase the transmission of painful stimuli. Coupled with this is an inhibition glycinergic neurons which normally inhibit pain transmission, a phenomenon known as disinhibition. Increased activity ofn-methyl d-aspartate (NMDA) and α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid (AMPA) receptors leads to the establishment of central sensitization, allowing both mild painful and innocuous stimuli to produce action potentials in nociceptive projection neurons. NSAIDs are effective in reducing mild-moderate acute and chronic nociceptive pain, however, the usefulness of NSAIDs in neuropathic pain is limited. The anti-inflammatory effect of NSAIDs is mediated by preventing vasodilation, increases in vascular permeability, and the release of cytokines from endothelial cells. These three effects together prevent immunocompetent cells from migrating to the site of injury thereby preventing additional damage and inflammation due to activation of the immune system at the site of damage. PGs also modulate T-helper cell activation and differentiation, an activity which is thought to be of importance in arthritic conditions. The anti-pyretic effect of NSAIDs is mediated through preventing increases in temperature by prostaglandins (PGs) via the hypothalamus. Activation of this process by other inflammatory mediators relies upon subsequent action by PGs, therefore NSAIDs are able to reduce fever due to these mediators as well. The adverse effects of NSAIDs are related to their therapeutic effects. The same vasodilatory action which occurs in inflammation also serves to regulate blood flow to the kidneys through the afferent renal arteries. NSAIDs are widely known as nephrotoxic agents as the reduction in PGs produces vasoconstriction of these arteries resulting in reduced blood flow to the kidneys and a subsequent decline in renal function. Reductions in mucus and HCO 3 secretion in the stomach increases the risk of ulceration by limiting the protection mediated by PGs. Lastly, COX-2 selective agents like nabumetone can unbalance prothrombotic and antithrombotic prostanoid generation leading to increased platelet aggregation and increased risk of thrombosis. •Mechanism of action (Drug A): Bupropion is a norepinephrine/dopamine-reuptake inhibitor (NDRI) that exerts its pharmacological effects by weakly inhibiting the enzymes involved in the uptake of the neurotransmitters norepinephrine and dopamine from the synaptic cleft, therefore prolonging their duration of action within the neuronal synapse and the downstream effects of these neurotransmitters. More specifically, bupropion binds to the norepinephrine transporter (NET) and the dopamine transporter (DAT). Bupropion was originally classified as an "atypical" antidepressant because it does not exert the same effects as the classical antidepressants such as Monoamine Oxidase Inhibitors (MAOIs), Tricyclic Antidepressants (TCAs), or Selective Serotonin Reuptake Inhibitors (SSRIs). While it has comparable effectiveness to typical first-line options for the treatment of depression such as SSRIs, bupropion is a unique option for the treatment of MDD as it lacks any clinically relevant serotonergic effects, typical of other mood medications, or any effects on histamine or adrenaline receptors. Lack of activity at these receptors results in a more tolerable side effect profile; bupropion is less likely to cause sexual side effects, sedation, or weight gain as compared to SSRIs or TCAs, for example. When used as an aid to smoking cessation, bupropion is thought to confer its anti-craving and anti-withdrawal effects by inhibiting dopamine reuptake, which is thought to be involved in the reward pathways associated with nicotine, and through the antagonism of the nicotinic acetylcholinergic receptor (AChR), thereby blunting the effects of nicotine. Furthermore, the stimulatory effects produced by bupropion in the central nervous system are similar to nicotine's effects, making low doses of bupropion a suitable option as a nicotine substitute. When used in combination with naltrexone in the marketed product ContraveⓇ for chronic weight management, the two components are thought to have effects on areas of the brain involved in the regulation of food intake. This includes the hypothalamus, which is involved in appetite regulation, and the mesolimbic dopamine circuit, which is involved in reward pathways. Studies have shown that the combined activity of bupropion and naltrexone increase the firing rate of hypothalamic pro-opiomelanocortin (POMC) neurons and blockade of opioid receptor-mediated POMC auto-inhibition, which are associated with a reduction in food intake and increased energy expenditure. This combination was also found to reduce food intake when injected directly into the ventral tegmental area of the mesolimbic circuit in mice, which is an area associated with the regulation of reward pathways. •Mechanism of action (Drug B): Nabumetone's active metabolite, 6-MNA, is an inhibitor of both COX-1 and COX-2 although it exhibits some COX-2 selectivity. Inhibition of COX-1 and COX-2 reduces conversion of arachidonic acid to PGs and thromboxane (TXA 2 ). This reduction in prostanoid production is the common mechanism that mediates the effects of nambutone. PGE 2 is the primary PG involved in modulation of nociception. It mediates peripheral sensitization through a variety of effects. PGE 2 activates the G q -coupled EP 1 receptor leading to increased activity of the inositol trisphosphate/phospholipase C pathway. Activation of this pathway releases intracellular stores of calcium which directly reduces action potential threshold and activates protein kinase C (PKC) which contributes to several indirect mechanisms. PGE 2 also activates the EP 4 receptor, coupled to G s, which activates the adenylyl cyclase/protein kinase A (AC/PKA) signaling pathway. PKA and PKC both contribute to the potentiation of transient receptor potential cation channel subfamily V member 1 (TRPV1) potentiation, which increases sensitivity to heat stimuli. They also activate tetrodotoxin-resistant sodium channels and inhibit inward potassium currents. PKA further contributes to the activation of the P2X3 purine receptor and sensitization of T-type calcium channels. The activation and sensitization of depolarizing ion channels and inhibition of inward potassium currents serve to reduce the intensity of stimulus necessary to generate action potentials in nociceptive sensory afferents. PGE 2 act via EP 3 to increase sensitivity to bradykinin and via EP 2 to further increase heat sensitivity. Central sensitization occurs in the dorsal horn of the spinal cord and is mediated by the EP 2 receptor which couples to G s. Pre-synaptically, this receptor increases the release of pro-nociceptive neurotransmitters glutamate, CGRP, and substance P. Post-synaptically it increases the activity of AMPA and NMDA receptors and produces inhibition of inhibitory glycinergic neurons. Together these lead to a reduced threshold of activating, allowing low intensity stimuli to generate pain signals. PGI 2 is known to play a role via its G s -coupled IP receptor although the magnitude of its contribution varies. It has been proposed to be of greater importance in painful inflammatory conditions such as arthritis. By limiting sensitization, both peripheral and central, via these pathways NSAIDs can effectively reduce inflammatory pain. PGI 2 and PGE 2 contribute to acute inflammation via their IP and EP 2 receptors. Similarly to β adrenergic receptors these are G s -coupled and mediate vasodilation through the AC/PKA pathway. PGE 2 also contributes by increasing leukocyte adhesion to the endothelium and attracts the cells to the site of injury. PGD 2 plays a role in the activation of endothelial cell release of cytokines through its DP 1 receptor. PGI 2 and PGE 2 modulate T-helper cell activation and differentiation through IP, EP 2, and EP 4 receptors which is believed to be an important activity in the pathology of arthritic conditions. By limiting the production of these PGs at the site of injury, NSAIDs can reduce inflammation. PGE 2 can cross the blood-brain barrier and act on excitatory G q EP 3 receptors on thermoregulatory neurons in the hypothalamus. This activation triggers an increase in heat-generation and a reduction in heat-loss to produce a fever. NSAIDs prevent the generation of PGE 2 thereby reducing the activity of these neurons. The adverse effects of NSAIDs stem from the protective and regulatory roles of prostanoids which have been well-characterized. PGI 2 and PGE 2 regulate blood flow to the kidney by similar mechanisms to the vasodilation they produce in inflammation. Prevention of this regulation by NSAIDs produces vasoconstriction which limits renal function by reducing blood flow and the hydrostatic pressure which drives filtration. PGE 2 also regulates gastric protection via EP 3 receptors which are, in this location, coupled to G i which inhibits the AC/PKA pathway. This reduces the secretion of protons by H /K ATPase in parietal cells and increases the secretion of mucus and HCO 3 by superficial endothelial cells. Disruption of this protective action by NSAIDs lead to ulceration of the gastric mucosa. Lastly, disruption of PGI 2, which opposes platelet aggregation, generation by COX-2 selective agents leads to an imbalance with TXA 2 generated by COX-1, which promotes aggregation of platelets, leading to increased risk of thrombosis. Since nabumetone is somewhat COX-2 selective it is thought to promote this imbalance and increase thrombotic risk. •Absorption (Drug A): Bupropion is currently available in 3 distinct, but bioequivalent formulations: immediate release (IR), sustained-release (SR), and extended-release (XL). Immediate Release Formulation In humans, following oral administration of bupropion hydrochloride tablets, peak plasma bupropion concentrations are usually achieved within 2 hours. IR formulations provide a short duration of action and are therefore generally dosed three times per day. Sustained Release Formulation In humans, following oral administration of bupropion hydrochloride sustained-release tablets (SR), peak plasma concentration (Cmax) of bupropion is usually achieved within 3 hours. SR formulations provide a 12-hour extended release of medication and are therefore generally dosed twice per day. Extended Release Formulation Following single oral administration of bupropion hydrochloride extended-release tablets (XL) to healthy volunteers, the median time to peak plasma concentrations for bupropion was approximately 5 hours. The presence of food did not affect the peak concentration or area under the curve of bupropion. XL formulations provide a 24-hour extended release of medication and are therefore generally dosed once per day/ In a trial comparing chronic dosing with bupropion hydrochloride extended-release tablets (SR) 150 mg twice daily to bupropion immediate-release formulation 100 mg 3 times daily, the steady state Cmax for bupropion after bupropion hydrochloride sustained-release tablets (SR) administration was approximately 85% of those achieved after bupropion immediate-release formulation administration. Exposure (AUC) to bupropion was equivalent for both formulations. Bioequivalence was also demonstrated for all three major active metabolites (i.e., hydroxybupropion, threohydrobupropion and erythrohydrobupropion) for both Cmax and AUC. Thus, at steady state, bupropion hydrochloride sustained-release tablets (SR) given twice daily, and the immediate-release formulation of bupropion given 3 times daily, are essentially bioequivalent for both bupropion and the 3 quantitatively important metabolites. Furthermore, in a study comparing 14-day dosing with bupropion hydrochloride extended-release tablets (XL), 300 mg once-daily to the immediate-release formulation of bupropion at 100 mg 3 times daily, equivalence was demonstrated for peak plasma concentration and area under the curve for bupropion and the three metabolites (hydroxybupropion, threohydrobupropion, and erythrohydrobupropion). Additionally, in a study comparing 14-day dosing with bupropion hydrochloride extended-release tablets (XL) 300 mg once daily to the sustained-release formulation of bupropion at 150 mg 2 times daily, equivalence was demonstrated for peak plasma concentration and area under the curve for bupropion and the three metabolites. Bupropion hydrochloride extended-release tablets (SR) can be taken with or without food. Bupropion Cmax and AUC were increased by 11% to 35% and 16% to 19%, respectively, when bupropion hydrochloride extended-release tablets (SR) was administered with food to healthy volunteers in three trials. The food effect is not considered clinically significant. Following a single-dose administration of bupropion hydrochloride extended-release tablets (SR) in humans, Cmax of bupropion's metabolite hydroxybupropion occurs approximately 6 hours post-dose and is approximately 10 times the peak level of the parent drug at steady state. The elimination half-life of hydroxybupropion is approximately 20 (±5) hours and its AUC at steady state is about 17 times that of bupropion. The times to peak concentrations for the erythrohydrobupropion and threohydrobupropion metabolites are similar to that of the hydroxybupropion metabolite. However, their elimination half-lives are longer, 33(±10) and 37 (±13) hours, respectively, and steady-state AUCs are 1.5 and 7 times that of bupropion, respectively. •Absorption (Drug B): Nabumetone is well-absorbed from the GI tract and undergoes significant first pass metabolism resulting in approximately 35% being converted to the active metabolite, 6-MNA. Tmax for 6-MNA varies widely with a mean values of 3 and 11 hours reported in official product monographs, and described as 9-12 hours in published literature Administration with food increases Cmax by 33% and increases absorption rate. If formulated as a suspension the Cmax increases and the Tmax is reduced by 0.8 hours while the all other pharmacokinetic parameters remain unchanged. •Volume of distribution (Drug A): No volume of distribution available •Volume of distribution (Drug B): The Vd of 6-MNA reported after administration of a single dose is 0.1-0.2 L/kg or approximately 5-10 L. Vdss reported in official product labeling is approximately 53 L. •Protein binding (Drug A): In vitro tests show that bupropion is 84% bound to human plasma proteins at concentrations up to 200 mcg per mL. The extent of protein binding of the hydroxybupropion metabolite is similar to that for bupropion, whereas the extent of protein binding of the threohydrobupropion metabolite is about half that seen with bupropion. •Protein binding (Drug B): 6-MNA is over 99% bound to plasma proteins, likely albumin. The unbound fraction is 0.1-0.2% and remains proportional in the dose range of 1000-2000mg •Metabolism (Drug A): Bupropion is extensively metabolized in humans. Three metabolites are active: hydroxybupropion, which is formed via hydroxylation of the tert-butyl group of bupropion, and the amino-alcohol isomers, threohydrobupropion and erythrohydrobupropion, which are formed via reduction of the carbonyl group. In vitro findings suggest that CYP2B6 is the principal isoenzyme involved in the formation of hydroxybupropion, while cytochrome P450 enzymes are not involved in the formation of threohydrobupropion. Hydroxybupropion has been shown to have the same affinity as bupropion for the norepinephrine transporter (NET) but approximately 50% of its antidepressant activity despite reaching concentrations of ~10-fold higher than that of the parent drug. Oxidation of the bupropion side chain results in the formation of a glycine conjugate of meta-chlorobenzoic acid, which is then excreted as the major urinary metabolite. The potency and toxicity of the metabolites relative to bupropion have not been fully characterized. However, it has been demonstrated in an antidepressant screening test in mice that hydroxybupropion is one-half as potent as bupropion, while threohydrobupropion and erythrohydrobupropion are 5-fold less potent than bupropion. This may be of clinical importance because the plasma concentrations of the metabolites are as high as or higher than those of bupropion. Bupropion and its metabolites exhibit linear kinetics following chronic administration of 300 to 450 mg per day. •Metabolism (Drug B): Nabumetone is reduced to 3-hydroxy nabumetone by the aldo-keto reductase-1C family and by corticosteroid 11-beta-dehydrogenase. It then undergoes oxidative cleavage by CYP1A2 to 6-MNA, the active metabolite. 6-MNA is eliminated by O-demethylation by CYP2C9 to 6-hydroxy-2-naphthylacetic acid (6-HNA). Both 6-MNA and 6-HNA are further converted to conjugates. Other metabolites are generated through a mix of ketone reduction and O-demethylation along with subsequent conjugation. Glucuronide conjugates of several metabolites have been found to become further conjugated to glycine residues. •Route of elimination (Drug A): Bupropion is extensively metabolized in humans. Oxidation of the bupropion side chain results in the formation of a glycine conjugate of metachlorobenzoic acid, which is then excreted as the major urinary metabolite. Following oral administration of 200 mg of 14C-bupropion in humans, 87% and 10% of the radioactive dose were recovered in the urine and feces, respectively. However, the fraction of the oral dose of bupropion excreted unchanged was only 0.5%, a finding consistent with the extensive metabolism of bupropion. •Route of elimination (Drug B): Most drug is eliminated via hepatic metabolism with minimal to no parent drug detectable in the plasma. 80% of the dose is then excreted by the kidneys and 10% in the feces. It does not appear to undergo enterohepatic recirculation. •Half-life (Drug A): 24 hours •Half-life (Drug B): 6-MNA has a mean half-life of 24 hours with a range of 19-36 hours. •Clearance (Drug A): No clearance available •Clearance (Drug B): 6-MNA has an apparent steady-state clearance of 20 - 30 mL/min. •Toxicity (Drug A): Symptoms of overdose include seizures, hallucinations, loss of consciousness, tachycardia, and cardiac arrest. •Toxicity (Drug B): LD 50 Values Mouse: 4290 mg/kg (Oral), 2380 mg/kg (IP) Rat: 3880 mg/kg (Oral), 1520 mg/kg (IP), >10 g/kg (SC) Monkey: 3200 mg/kg (Oral) Overdose Signs and symptoms of nabumetone overdose include lethargy, drowsiness, nausea, vomiting, and epigastric pain. These are considered reversible with supportive care. GI bleeding, hypertension, acute kidney injury, respiratory depression, and coma are rare but can occur. No antidote exists for nabumetone overdose although administration of activated charcoal and/or induction of emesis can reduce absorption if the nabumetone dose was taken less than 4 hours prior. 6-MNA is cannot be cleared by dialysis. Carcinogenicity & Mutagenicity Nabumetone was not significantly carcinogenic in rats or mice studied over 2 years. Neither the Ames test nor mouse micronucleus test showed nabumetone or it's active metabolite, 6-MNA, to be mutagenic. Chromosomal abberation has been observed in cultured lymphocytes exposed to concentrations of 80 mcg/mL and higher of nabumetone or 6-MNA equivalent to the maximum recommended human dose. Reproductive Toxicity No adverse effects on fertility have been observed in male and female rats at doses of 320 mg/kg/day. ] No teratogenicity has been observed in pregnant rabbits or rats. Dystocia and delayed parturition have been noted in rats resulting in reduced survival of offspring. This has been attributed to the role of prostaglandins in uterine contraction. NSAIDs can also cause premature closure of the ductus ateriosus. Lactation 6-MNA has been detected in the milk of lactating rats. While no data is available in humans, 6-MNA is both highly protein bound and exists in its anionic form in circulation. For these reasons partitioning into breast milk is expected to be limited. •Brand Names (Drug A): Aplenzin, Auvelity, Budeprion, Contrave, Forfivo, Wellbutrin, Zyban •Brand Names (Drug B): Relafen •Synonyms (Drug A): No synonyms listed •Synonyms (Drug B): Nabumeton Nabumetona Nabumétone Nabumetone Nabumetonum •Summary (Drug A): Bupropion is a norepinephrine and dopamine reuptake inhibitor used in the treatment of major depressive disorder (MDD), seasonal affective disorder (SAD), and as an aid to smoking cessation. •Summary (Drug B): Nabumetone is an NSAID used to treat osteoarthritis and rheumatoid arthritis. Output: The subject drug is a nephrotoxic agent that may potentially impair renal function and decrease the excretion of drugs that mainly undergo renal excretion as the principal mode of clearance, such as the affected drug. Attenuated renal excretion of the affected drug may increase drug concentrations, leading to an elevated risk for drug-related adverse effects. The severity of the interaction is minor.

Does Bupropion and Nadolol interact?

•Drug A: Bupropion •Drug B: Nadolol •Severity: MAJOR •Description: The metabolism of Nadolol can be decreased when combined with Bupropion. •Extended Description: The subject drug is a strong CYP2D6 inhibitor and the affected drug is metabolized by CYP2D6. Concomitant administration may decrease the metabolism of the affected drug, which could increase serum concentrations as well as the risk and severity of adverse effects. •Indication (Drug A): Bupropion is indicated for the treatment of major depressive disorder (MDD), seasonal affective disorder (SAD), and as an aid to smoking cessation. When used in combination with naltrexone as the marketed product ContraveⓇ, bupropion is indicated as an adjunct to a reduced-calorie diet and increased physical activity for chronic weight management in adults with an initial body mass index (BMI) of: 30 kg/m^2 or greater (obese) or 27 kg/m^2 or greater (overweight) in the presence of at least one weight-related comorbid condition (e.g., hypertension, type 2 diabetes mellitus, or dyslipidemia). Bupropion is also used off-label as a first-line treatment in patients with ADHD and comorbid bipolar disorder when used as an adjunct to mood stabilizers. •Indication (Drug B): Nadolol is indicated to treat angina pectoris and hypertension. Another product formulated with bendroflumethiazide is indicated to treat hypertension. •Pharmacodynamics (Drug A): Bupropion is chemically unrelated to tricyclic, tetracyclic, selective serotonin re-uptake inhibitors, or other known antidepressant agents. Compared to classical tricyclic antidepressants, Bupropion is a relatively weak inhibitor of the neuronal uptake of norepinephrine and dopamine. In addition, Bupropion does not inhibit monoamine oxidase. Bupropion has been found to be essentially inactive at the serotonin transporter (SERT)(IC50 >10 000 nM), however both bupropion and its primary metabolite hydroxybupropion have been found to block the function of cation-selective serotonin type 3A receptors (5-HT3ARs). Bupropion produces dose-related central nervous system (CNS) stimulant effects in animals, as evidenced by increased locomotor activity, increased rates of responding in various schedule-controlled operant behaviour tasks, and, at high doses, induction of mild stereotyped behaviour. Due to these stimulant effects and selective activity at dopamine and norepinephrine receptors, bupropion has been identified as having an abuse potential. Bupropion has a similar structure to the controlled substance Cathinone, and has been identified as having mild amphetamine-like activity, particularly when inhaled or injected. Bupropion is also known to lower the seizure threshold, making any pre-existing seizure conditions a contraindication to its use. This risk is exacerbated when bupropion is combined with other drugs or substances that lower the seizure threshold, such as cocaine, or in clinical situations that would increase the risk of a seizure such as abrupt alcohol or benzodiazepine withdrawal. As norepinephrine has been shown to have anticonvulsant properties, bupropion's inhibitory effects on NET are thought to contribute to its pro-convulsant activity. Bupropion has been shown to increase blood pressure and pose a risk for exacerbation of unmanaged or pre-existing hypertension, however, clinical trials of bupropion in smokers with CVD have not identified an increased incidence of CV events including stroke or heart attack. In clinical trials, the mean increase in systolic blood pressure associated with the use of bupropion was found to be 1.3 mmHg. •Pharmacodynamics (Drug B): Nadolol is a nonselective beta adrenal receptor blocker that is used to lower blood pressure. It has a long duration of action as it is usually taken once daily and a wide therapeutic index as patients start at doses of 40mg daily but may be increased to doses as high as 240mg daily. Patients taking nadolol should not aburptly stop taking it as this may lead to exacerbation of ischemic heart disease. •Mechanism of action (Drug A): Bupropion is a norepinephrine/dopamine-reuptake inhibitor (NDRI) that exerts its pharmacological effects by weakly inhibiting the enzymes involved in the uptake of the neurotransmitters norepinephrine and dopamine from the synaptic cleft, therefore prolonging their duration of action within the neuronal synapse and the downstream effects of these neurotransmitters. More specifically, bupropion binds to the norepinephrine transporter (NET) and the dopamine transporter (DAT). Bupropion was originally classified as an "atypical" antidepressant because it does not exert the same effects as the classical antidepressants such as Monoamine Oxidase Inhibitors (MAOIs), Tricyclic Antidepressants (TCAs), or Selective Serotonin Reuptake Inhibitors (SSRIs). While it has comparable effectiveness to typical first-line options for the treatment of depression such as SSRIs, bupropion is a unique option for the treatment of MDD as it lacks any clinically relevant serotonergic effects, typical of other mood medications, or any effects on histamine or adrenaline receptors. Lack of activity at these receptors results in a more tolerable side effect profile; bupropion is less likely to cause sexual side effects, sedation, or weight gain as compared to SSRIs or TCAs, for example. When used as an aid to smoking cessation, bupropion is thought to confer its anti-craving and anti-withdrawal effects by inhibiting dopamine reuptake, which is thought to be involved in the reward pathways associated with nicotine, and through the antagonism of the nicotinic acetylcholinergic receptor (AChR), thereby blunting the effects of nicotine. Furthermore, the stimulatory effects produced by bupropion in the central nervous system are similar to nicotine's effects, making low doses of bupropion a suitable option as a nicotine substitute. When used in combination with naltrexone in the marketed product ContraveⓇ for chronic weight management, the two components are thought to have effects on areas of the brain involved in the regulation of food intake. This includes the hypothalamus, which is involved in appetite regulation, and the mesolimbic dopamine circuit, which is involved in reward pathways. Studies have shown that the combined activity of bupropion and naltrexone increase the firing rate of hypothalamic pro-opiomelanocortin (POMC) neurons and blockade of opioid receptor-mediated POMC auto-inhibition, which are associated with a reduction in food intake and increased energy expenditure. This combination was also found to reduce food intake when injected directly into the ventral tegmental area of the mesolimbic circuit in mice, which is an area associated with the regulation of reward pathways. •Mechanism of action (Drug B): Although nadolol is described as a non selective beta blocker, it does not interact with beta 3 adrenal receptors. Antagonism of beta-1 and beta-2 adrenoceptors in the heart inhibits cyclic AMP and its signalling pathway, decreasing the strength and speed of contractions as well as the speed of relaxation and conduction. Antagonism of beta-2 adrenoceptors in the smooth muscle cells of the vasculature inhibits their relaxation, leading to an increase in peripheral vascular resistance and reducing the risk of severe hypotension. The increase in peripheral vascular resistance may contribute to the decrease in insulin sensitivity associated with nadolol use. Antagonism of beta-1 adrenoceptors in the juxtaglomerular apparatus of the kidney inhibits the release of renin, and therefore angiotensin II mediated vasoconstriction, aldosterone mediated water retention, and the release of epinephrine. Antagonism of beta-2 adrenoceptors in the liver and skeletal muscle inhibits glycogenolysis, in the lungs prevents bronchodilation, and in the pancrease inhibits insulin release. •Absorption (Drug A): Bupropion is currently available in 3 distinct, but bioequivalent formulations: immediate release (IR), sustained-release (SR), and extended-release (XL). Immediate Release Formulation In humans, following oral administration of bupropion hydrochloride tablets, peak plasma bupropion concentrations are usually achieved within 2 hours. IR formulations provide a short duration of action and are therefore generally dosed three times per day. Sustained Release Formulation In humans, following oral administration of bupropion hydrochloride sustained-release tablets (SR), peak plasma concentration (Cmax) of bupropion is usually achieved within 3 hours. SR formulations provide a 12-hour extended release of medication and are therefore generally dosed twice per day. Extended Release Formulation Following single oral administration of bupropion hydrochloride extended-release tablets (XL) to healthy volunteers, the median time to peak plasma concentrations for bupropion was approximately 5 hours. The presence of food did not affect the peak concentration or area under the curve of bupropion. XL formulations provide a 24-hour extended release of medication and are therefore generally dosed once per day/ In a trial comparing chronic dosing with bupropion hydrochloride extended-release tablets (SR) 150 mg twice daily to bupropion immediate-release formulation 100 mg 3 times daily, the steady state Cmax for bupropion after bupropion hydrochloride sustained-release tablets (SR) administration was approximately 85% of those achieved after bupropion immediate-release formulation administration. Exposure (AUC) to bupropion was equivalent for both formulations. Bioequivalence was also demonstrated for all three major active metabolites (i.e., hydroxybupropion, threohydrobupropion and erythrohydrobupropion) for both Cmax and AUC. Thus, at steady state, bupropion hydrochloride sustained-release tablets (SR) given twice daily, and the immediate-release formulation of bupropion given 3 times daily, are essentially bioequivalent for both bupropion and the 3 quantitatively important metabolites. Furthermore, in a study comparing 14-day dosing with bupropion hydrochloride extended-release tablets (XL), 300 mg once-daily to the immediate-release formulation of bupropion at 100 mg 3 times daily, equivalence was demonstrated for peak plasma concentration and area under the curve for bupropion and the three metabolites (hydroxybupropion, threohydrobupropion, and erythrohydrobupropion). Additionally, in a study comparing 14-day dosing with bupropion hydrochloride extended-release tablets (XL) 300 mg once daily to the sustained-release formulation of bupropion at 150 mg 2 times daily, equivalence was demonstrated for peak plasma concentration and area under the curve for bupropion and the three metabolites. Bupropion hydrochloride extended-release tablets (SR) can be taken with or without food. Bupropion Cmax and AUC were increased by 11% to 35% and 16% to 19%, respectively, when bupropion hydrochloride extended-release tablets (SR) was administered with food to healthy volunteers in three trials. The food effect is not considered clinically significant. Following a single-dose administration of bupropion hydrochloride extended-release tablets (SR) in humans, Cmax of bupropion's metabolite hydroxybupropion occurs approximately 6 hours post-dose and is approximately 10 times the peak level of the parent drug at steady state. The elimination half-life of hydroxybupropion is approximately 20 (±5) hours and its AUC at steady state is about 17 times that of bupropion. The times to peak concentrations for the erythrohydrobupropion and threohydrobupropion metabolites are similar to that of the hydroxybupropion metabolite. However, their elimination half-lives are longer, 33(±10) and 37 (±13) hours, respectively, and steady-state AUCs are 1.5 and 7 times that of bupropion, respectively. •Absorption (Drug B): Oral doses of nadolol are approximately 30% absorbed. In healthy subjects, nadolol has a T max of 2.7h with a C max or 69±15ng/mL following a 60mg oral dose and 132±27ng/mL after a 120mg oral dose. The AUC following a 60mg oral dose was 1021ng*h/mL and following a 120mg oral dose was 1913±382ng*h/mL. •Volume of distribution (Drug A): No volume of distribution available •Volume of distribution (Drug B): In healthy subjects, the volume of distribution of nadolol is 147-157L. •Protein binding (Drug A): In vitro tests show that bupropion is 84% bound to human plasma proteins at concentrations up to 200 mcg per mL. The extent of protein binding of the hydroxybupropion metabolite is similar to that for bupropion, whereas the extent of protein binding of the threohydrobupropion metabolite is about half that seen with bupropion. •Protein binding (Drug B): Nadolol is approximately 30% bound to plasma protein. Nadolol binds to alpha-1-acid glycoprotein in plasma. •Metabolism (Drug A): Bupropion is extensively metabolized in humans. Three metabolites are active: hydroxybupropion, which is formed via hydroxylation of the tert-butyl group of bupropion, and the amino-alcohol isomers, threohydrobupropion and erythrohydrobupropion, which are formed via reduction of the carbonyl group. In vitro findings suggest that CYP2B6 is the principal isoenzyme involved in the formation of hydroxybupropion, while cytochrome P450 enzymes are not involved in the formation of threohydrobupropion. Hydroxybupropion has been shown to have the same affinity as bupropion for the norepinephrine transporter (NET) but approximately 50% of its antidepressant activity despite reaching concentrations of ~10-fold higher than that of the parent drug. Oxidation of the bupropion side chain results in the formation of a glycine conjugate of meta-chlorobenzoic acid, which is then excreted as the major urinary metabolite. The potency and toxicity of the metabolites relative to bupropion have not been fully characterized. However, it has been demonstrated in an antidepressant screening test in mice that hydroxybupropion is one-half as potent as bupropion, while threohydrobupropion and erythrohydrobupropion are 5-fold less potent than bupropion. This may be of clinical importance because the plasma concentrations of the metabolites are as high as or higher than those of bupropion. Bupropion and its metabolites exhibit linear kinetics following chronic administration of 300 to 450 mg per day. •Metabolism (Drug B): Nadolol is not metabolized by the liver in humans. •Route of elimination (Drug A): Bupropion is extensively metabolized in humans. Oxidation of the bupropion side chain results in the formation of a glycine conjugate of metachlorobenzoic acid, which is then excreted as the major urinary metabolite. Following oral administration of 200 mg of 14C-bupropion in humans, 87% and 10% of the radioactive dose were recovered in the urine and feces, respectively. However, the fraction of the oral dose of bupropion excreted unchanged was only 0.5%, a finding consistent with the extensive metabolism of bupropion. •Route of elimination (Drug B): Nadolol is not metabolized in the liver and excreted mainly in the urine. In healthy subjects, following intravenous dosing, 60% of a dose is eliminated in the urine and 15% in the feces after 72 hours. The remainder of the dose is expected to be eliminated in the feces afterwards. •Half-life (Drug A): 24 hours •Half-life (Drug B): The half life of nadolol is 20 to 24 hours. •Clearance (Drug A): No clearance available •Clearance (Drug B): In healthy subjects, the total body clearance of nadolol is 219-250mL/min and the renal clearance is 131-150mL/min. •Toxicity (Drug A): Symptoms of overdose include seizures, hallucinations, loss of consciousness, tachycardia, and cardiac arrest. •Toxicity (Drug B): The oral LD 50 in mice is 4500mg/kg. Patients experiencing an overdose may present with bradycardia, cardiac failure, hypotension, and bronchospasm. An overdose may be treated with atropine for bradycardia, digitalis and diuretics for cardiac failure, vasopressors for hypotension, and beta-2 stimulants for bronchospasms, as well as gastric lavage and hemodialysis. •Brand Names (Drug A): Aplenzin, Auvelity, Budeprion, Contrave, Forfivo, Wellbutrin, Zyban •Brand Names (Drug B): Corgard •Synonyms (Drug A): No synonyms listed •Synonyms (Drug B): No synonyms listed •Summary (Drug A): Bupropion is a norepinephrine and dopamine reuptake inhibitor used in the treatment of major depressive disorder (MDD), seasonal affective disorder (SAD), and as an aid to smoking cessation. •Summary (Drug B): Nadolol is a non-selective beta-adrenergic antagonist used for the management of arrhythmias, angina pectoris, and hypertension.

The subject drug is a strong CYP2D6 inhibitor and the affected drug is metabolized by CYP2D6. Concomitant administration may decrease the metabolism of the affected drug, which could increase serum concentrations as well as the risk and severity of adverse effects. The severity of the interaction is major.

Question: Does Bupropion and Nadolol interact? Information: •Drug A: Bupropion •Drug B: Nadolol •Severity: MAJOR •Description: The metabolism of Nadolol can be decreased when combined with Bupropion. •Extended Description: The subject drug is a strong CYP2D6 inhibitor and the affected drug is metabolized by CYP2D6. Concomitant administration may decrease the metabolism of the affected drug, which could increase serum concentrations as well as the risk and severity of adverse effects. •Indication (Drug A): Bupropion is indicated for the treatment of major depressive disorder (MDD), seasonal affective disorder (SAD), and as an aid to smoking cessation. When used in combination with naltrexone as the marketed product ContraveⓇ, bupropion is indicated as an adjunct to a reduced-calorie diet and increased physical activity for chronic weight management in adults with an initial body mass index (BMI) of: 30 kg/m^2 or greater (obese) or 27 kg/m^2 or greater (overweight) in the presence of at least one weight-related comorbid condition (e.g., hypertension, type 2 diabetes mellitus, or dyslipidemia). Bupropion is also used off-label as a first-line treatment in patients with ADHD and comorbid bipolar disorder when used as an adjunct to mood stabilizers. •Indication (Drug B): Nadolol is indicated to treat angina pectoris and hypertension. Another product formulated with bendroflumethiazide is indicated to treat hypertension. •Pharmacodynamics (Drug A): Bupropion is chemically unrelated to tricyclic, tetracyclic, selective serotonin re-uptake inhibitors, or other known antidepressant agents. Compared to classical tricyclic antidepressants, Bupropion is a relatively weak inhibitor of the neuronal uptake of norepinephrine and dopamine. In addition, Bupropion does not inhibit monoamine oxidase. Bupropion has been found to be essentially inactive at the serotonin transporter (SERT)(IC50 >10 000 nM), however both bupropion and its primary metabolite hydroxybupropion have been found to block the function of cation-selective serotonin type 3A receptors (5-HT3ARs). Bupropion produces dose-related central nervous system (CNS) stimulant effects in animals, as evidenced by increased locomotor activity, increased rates of responding in various schedule-controlled operant behaviour tasks, and, at high doses, induction of mild stereotyped behaviour. Due to these stimulant effects and selective activity at dopamine and norepinephrine receptors, bupropion has been identified as having an abuse potential. Bupropion has a similar structure to the controlled substance Cathinone, and has been identified as having mild amphetamine-like activity, particularly when inhaled or injected. Bupropion is also known to lower the seizure threshold, making any pre-existing seizure conditions a contraindication to its use. This risk is exacerbated when bupropion is combined with other drugs or substances that lower the seizure threshold, such as cocaine, or in clinical situations that would increase the risk of a seizure such as abrupt alcohol or benzodiazepine withdrawal. As norepinephrine has been shown to have anticonvulsant properties, bupropion's inhibitory effects on NET are thought to contribute to its pro-convulsant activity. Bupropion has been shown to increase blood pressure and pose a risk for exacerbation of unmanaged or pre-existing hypertension, however, clinical trials of bupropion in smokers with CVD have not identified an increased incidence of CV events including stroke or heart attack. In clinical trials, the mean increase in systolic blood pressure associated with the use of bupropion was found to be 1.3 mmHg. •Pharmacodynamics (Drug B): Nadolol is a nonselective beta adrenal receptor blocker that is used to lower blood pressure. It has a long duration of action as it is usually taken once daily and a wide therapeutic index as patients start at doses of 40mg daily but may be increased to doses as high as 240mg daily. Patients taking nadolol should not aburptly stop taking it as this may lead to exacerbation of ischemic heart disease. •Mechanism of action (Drug A): Bupropion is a norepinephrine/dopamine-reuptake inhibitor (NDRI) that exerts its pharmacological effects by weakly inhibiting the enzymes involved in the uptake of the neurotransmitters norepinephrine and dopamine from the synaptic cleft, therefore prolonging their duration of action within the neuronal synapse and the downstream effects of these neurotransmitters. More specifically, bupropion binds to the norepinephrine transporter (NET) and the dopamine transporter (DAT). Bupropion was originally classified as an "atypical" antidepressant because it does not exert the same effects as the classical antidepressants such as Monoamine Oxidase Inhibitors (MAOIs), Tricyclic Antidepressants (TCAs), or Selective Serotonin Reuptake Inhibitors (SSRIs). While it has comparable effectiveness to typical first-line options for the treatment of depression such as SSRIs, bupropion is a unique option for the treatment of MDD as it lacks any clinically relevant serotonergic effects, typical of other mood medications, or any effects on histamine or adrenaline receptors. Lack of activity at these receptors results in a more tolerable side effect profile; bupropion is less likely to cause sexual side effects, sedation, or weight gain as compared to SSRIs or TCAs, for example. When used as an aid to smoking cessation, bupropion is thought to confer its anti-craving and anti-withdrawal effects by inhibiting dopamine reuptake, which is thought to be involved in the reward pathways associated with nicotine, and through the antagonism of the nicotinic acetylcholinergic receptor (AChR), thereby blunting the effects of nicotine. Furthermore, the stimulatory effects produced by bupropion in the central nervous system are similar to nicotine's effects, making low doses of bupropion a suitable option as a nicotine substitute. When used in combination with naltrexone in the marketed product ContraveⓇ for chronic weight management, the two components are thought to have effects on areas of the brain involved in the regulation of food intake. This includes the hypothalamus, which is involved in appetite regulation, and the mesolimbic dopamine circuit, which is involved in reward pathways. Studies have shown that the combined activity of bupropion and naltrexone increase the firing rate of hypothalamic pro-opiomelanocortin (POMC) neurons and blockade of opioid receptor-mediated POMC auto-inhibition, which are associated with a reduction in food intake and increased energy expenditure. This combination was also found to reduce food intake when injected directly into the ventral tegmental area of the mesolimbic circuit in mice, which is an area associated with the regulation of reward pathways. •Mechanism of action (Drug B): Although nadolol is described as a non selective beta blocker, it does not interact with beta 3 adrenal receptors. Antagonism of beta-1 and beta-2 adrenoceptors in the heart inhibits cyclic AMP and its signalling pathway, decreasing the strength and speed of contractions as well as the speed of relaxation and conduction. Antagonism of beta-2 adrenoceptors in the smooth muscle cells of the vasculature inhibits their relaxation, leading to an increase in peripheral vascular resistance and reducing the risk of severe hypotension. The increase in peripheral vascular resistance may contribute to the decrease in insulin sensitivity associated with nadolol use. Antagonism of beta-1 adrenoceptors in the juxtaglomerular apparatus of the kidney inhibits the release of renin, and therefore angiotensin II mediated vasoconstriction, aldosterone mediated water retention, and the release of epinephrine. Antagonism of beta-2 adrenoceptors in the liver and skeletal muscle inhibits glycogenolysis, in the lungs prevents bronchodilation, and in the pancrease inhibits insulin release. •Absorption (Drug A): Bupropion is currently available in 3 distinct, but bioequivalent formulations: immediate release (IR), sustained-release (SR), and extended-release (XL). Immediate Release Formulation In humans, following oral administration of bupropion hydrochloride tablets, peak plasma bupropion concentrations are usually achieved within 2 hours. IR formulations provide a short duration of action and are therefore generally dosed three times per day. Sustained Release Formulation In humans, following oral administration of bupropion hydrochloride sustained-release tablets (SR), peak plasma concentration (Cmax) of bupropion is usually achieved within 3 hours. SR formulations provide a 12-hour extended release of medication and are therefore generally dosed twice per day. Extended Release Formulation Following single oral administration of bupropion hydrochloride extended-release tablets (XL) to healthy volunteers, the median time to peak plasma concentrations for bupropion was approximately 5 hours. The presence of food did not affect the peak concentration or area under the curve of bupropion. XL formulations provide a 24-hour extended release of medication and are therefore generally dosed once per day/ In a trial comparing chronic dosing with bupropion hydrochloride extended-release tablets (SR) 150 mg twice daily to bupropion immediate-release formulation 100 mg 3 times daily, the steady state Cmax for bupropion after bupropion hydrochloride sustained-release tablets (SR) administration was approximately 85% of those achieved after bupropion immediate-release formulation administration. Exposure (AUC) to bupropion was equivalent for both formulations. Bioequivalence was also demonstrated for all three major active metabolites (i.e., hydroxybupropion, threohydrobupropion and erythrohydrobupropion) for both Cmax and AUC. Thus, at steady state, bupropion hydrochloride sustained-release tablets (SR) given twice daily, and the immediate-release formulation of bupropion given 3 times daily, are essentially bioequivalent for both bupropion and the 3 quantitatively important metabolites. Furthermore, in a study comparing 14-day dosing with bupropion hydrochloride extended-release tablets (XL), 300 mg once-daily to the immediate-release formulation of bupropion at 100 mg 3 times daily, equivalence was demonstrated for peak plasma concentration and area under the curve for bupropion and the three metabolites (hydroxybupropion, threohydrobupropion, and erythrohydrobupropion). Additionally, in a study comparing 14-day dosing with bupropion hydrochloride extended-release tablets (XL) 300 mg once daily to the sustained-release formulation of bupropion at 150 mg 2 times daily, equivalence was demonstrated for peak plasma concentration and area under the curve for bupropion and the three metabolites. Bupropion hydrochloride extended-release tablets (SR) can be taken with or without food. Bupropion Cmax and AUC were increased by 11% to 35% and 16% to 19%, respectively, when bupropion hydrochloride extended-release tablets (SR) was administered with food to healthy volunteers in three trials. The food effect is not considered clinically significant. Following a single-dose administration of bupropion hydrochloride extended-release tablets (SR) in humans, Cmax of bupropion's metabolite hydroxybupropion occurs approximately 6 hours post-dose and is approximately 10 times the peak level of the parent drug at steady state. The elimination half-life of hydroxybupropion is approximately 20 (±5) hours and its AUC at steady state is about 17 times that of bupropion. The times to peak concentrations for the erythrohydrobupropion and threohydrobupropion metabolites are similar to that of the hydroxybupropion metabolite. However, their elimination half-lives are longer, 33(±10) and 37 (±13) hours, respectively, and steady-state AUCs are 1.5 and 7 times that of bupropion, respectively. •Absorption (Drug B): Oral doses of nadolol are approximately 30% absorbed. In healthy subjects, nadolol has a T max of 2.7h with a C max or 69±15ng/mL following a 60mg oral dose and 132±27ng/mL after a 120mg oral dose. The AUC following a 60mg oral dose was 1021ng*h/mL and following a 120mg oral dose was 1913±382ng*h/mL. •Volume of distribution (Drug A): No volume of distribution available •Volume of distribution (Drug B): In healthy subjects, the volume of distribution of nadolol is 147-157L. •Protein binding (Drug A): In vitro tests show that bupropion is 84% bound to human plasma proteins at concentrations up to 200 mcg per mL. The extent of protein binding of the hydroxybupropion metabolite is similar to that for bupropion, whereas the extent of protein binding of the threohydrobupropion metabolite is about half that seen with bupropion. •Protein binding (Drug B): Nadolol is approximately 30% bound to plasma protein. Nadolol binds to alpha-1-acid glycoprotein in plasma. •Metabolism (Drug A): Bupropion is extensively metabolized in humans. Three metabolites are active: hydroxybupropion, which is formed via hydroxylation of the tert-butyl group of bupropion, and the amino-alcohol isomers, threohydrobupropion and erythrohydrobupropion, which are formed via reduction of the carbonyl group. In vitro findings suggest that CYP2B6 is the principal isoenzyme involved in the formation of hydroxybupropion, while cytochrome P450 enzymes are not involved in the formation of threohydrobupropion. Hydroxybupropion has been shown to have the same affinity as bupropion for the norepinephrine transporter (NET) but approximately 50% of its antidepressant activity despite reaching concentrations of ~10-fold higher than that of the parent drug. Oxidation of the bupropion side chain results in the formation of a glycine conjugate of meta-chlorobenzoic acid, which is then excreted as the major urinary metabolite. The potency and toxicity of the metabolites relative to bupropion have not been fully characterized. However, it has been demonstrated in an antidepressant screening test in mice that hydroxybupropion is one-half as potent as bupropion, while threohydrobupropion and erythrohydrobupropion are 5-fold less potent than bupropion. This may be of clinical importance because the plasma concentrations of the metabolites are as high as or higher than those of bupropion. Bupropion and its metabolites exhibit linear kinetics following chronic administration of 300 to 450 mg per day. •Metabolism (Drug B): Nadolol is not metabolized by the liver in humans. •Route of elimination (Drug A): Bupropion is extensively metabolized in humans. Oxidation of the bupropion side chain results in the formation of a glycine conjugate of metachlorobenzoic acid, which is then excreted as the major urinary metabolite. Following oral administration of 200 mg of 14C-bupropion in humans, 87% and 10% of the radioactive dose were recovered in the urine and feces, respectively. However, the fraction of the oral dose of bupropion excreted unchanged was only 0.5%, a finding consistent with the extensive metabolism of bupropion. •Route of elimination (Drug B): Nadolol is not metabolized in the liver and excreted mainly in the urine. In healthy subjects, following intravenous dosing, 60% of a dose is eliminated in the urine and 15% in the feces after 72 hours. The remainder of the dose is expected to be eliminated in the feces afterwards. •Half-life (Drug A): 24 hours •Half-life (Drug B): The half life of nadolol is 20 to 24 hours. •Clearance (Drug A): No clearance available •Clearance (Drug B): In healthy subjects, the total body clearance of nadolol is 219-250mL/min and the renal clearance is 131-150mL/min. •Toxicity (Drug A): Symptoms of overdose include seizures, hallucinations, loss of consciousness, tachycardia, and cardiac arrest. •Toxicity (Drug B): The oral LD 50 in mice is 4500mg/kg. Patients experiencing an overdose may present with bradycardia, cardiac failure, hypotension, and bronchospasm. An overdose may be treated with atropine for bradycardia, digitalis and diuretics for cardiac failure, vasopressors for hypotension, and beta-2 stimulants for bronchospasms, as well as gastric lavage and hemodialysis. •Brand Names (Drug A): Aplenzin, Auvelity, Budeprion, Contrave, Forfivo, Wellbutrin, Zyban •Brand Names (Drug B): Corgard •Synonyms (Drug A): No synonyms listed •Synonyms (Drug B): No synonyms listed •Summary (Drug A): Bupropion is a norepinephrine and dopamine reuptake inhibitor used in the treatment of major depressive disorder (MDD), seasonal affective disorder (SAD), and as an aid to smoking cessation. •Summary (Drug B): Nadolol is a non-selective beta-adrenergic antagonist used for the management of arrhythmias, angina pectoris, and hypertension. Output: The subject drug is a strong CYP2D6 inhibitor and the affected drug is metabolized by CYP2D6. Concomitant administration may decrease the metabolism of the affected drug, which could increase serum concentrations as well as the risk and severity of adverse effects. The severity of the interaction is major.

Does Bupropion and Nalbuphine interact?

•Drug A: Bupropion •Drug B: Nalbuphine •Severity: MODERATE •Description: The risk or severity of CNS depression can be increased when Nalbuphine is combined with Bupropion. •Extended Description: Central nervous system (CNS) depressants can cause sedation, falls, respiratory depression, coma, and death.2,3 The potential interaction between a CNS depressant and another CNS depressant drug due to synergistic effects is well documented in the literature, although the risk and severity of CNS depression vary from each drug. The subject and affected drugs are both CNS depressants that, when co-administered, may result in a more profound CNS depression. As the risk and severity of CNS depression resulting from the combined use of CNS depressants vary from each agent, each interaction between CNS depressants should be considered individually. •Indication (Drug A): Bupropion is indicated for the treatment of major depressive disorder (MDD), seasonal affective disorder (SAD), and as an aid to smoking cessation. When used in combination with naltrexone as the marketed product ContraveⓇ, bupropion is indicated as an adjunct to a reduced-calorie diet and increased physical activity for chronic weight management in adults with an initial body mass index (BMI) of: 30 kg/m^2 or greater (obese) or 27 kg/m^2 or greater (overweight) in the presence of at least one weight-related comorbid condition (e.g., hypertension, type 2 diabetes mellitus, or dyslipidemia). Bupropion is also used off-label as a first-line treatment in patients with ADHD and comorbid bipolar disorder when used as an adjunct to mood stabilizers. •Indication (Drug B): For the relief of moderate to severe pain. •Pharmacodynamics (Drug A): Bupropion is chemically unrelated to tricyclic, tetracyclic, selective serotonin re-uptake inhibitors, or other known antidepressant agents. Compared to classical tricyclic antidepressants, Bupropion is a relatively weak inhibitor of the neuronal uptake of norepinephrine and dopamine. In addition, Bupropion does not inhibit monoamine oxidase. Bupropion has been found to be essentially inactive at the serotonin transporter (SERT)(IC50 >10 000 nM), however both bupropion and its primary metabolite hydroxybupropion have been found to block the function of cation-selective serotonin type 3A receptors (5-HT3ARs). Bupropion produces dose-related central nervous system (CNS) stimulant effects in animals, as evidenced by increased locomotor activity, increased rates of responding in various schedule-controlled operant behaviour tasks, and, at high doses, induction of mild stereotyped behaviour. Due to these stimulant effects and selective activity at dopamine and norepinephrine receptors, bupropion has been identified as having an abuse potential. Bupropion has a similar structure to the controlled substance Cathinone, and has been identified as having mild amphetamine-like activity, particularly when inhaled or injected. Bupropion is also known to lower the seizure threshold, making any pre-existing seizure conditions a contraindication to its use. This risk is exacerbated when bupropion is combined with other drugs or substances that lower the seizure threshold, such as cocaine, or in clinical situations that would increase the risk of a seizure such as abrupt alcohol or benzodiazepine withdrawal. As norepinephrine has been shown to have anticonvulsant properties, bupropion's inhibitory effects on NET are thought to contribute to its pro-convulsant activity. Bupropion has been shown to increase blood pressure and pose a risk for exacerbation of unmanaged or pre-existing hypertension, however, clinical trials of bupropion in smokers with CVD have not identified an increased incidence of CV events including stroke or heart attack. In clinical trials, the mean increase in systolic blood pressure associated with the use of bupropion was found to be 1.3 mmHg. •Pharmacodynamics (Drug B): Nalbuphine is a synthetic opioid agonist-antagonist analgesic of the phenanthrene series. Nalbuphine's analgesic potency is essentially equivalent to that of morphine on a milligram basis. The opoioid antagonist activity of nalbuphine is about one-fourth to that of nalorphine and 10 times to that of pentazocine. Nalbuphine by itself has potent opioid antagonist activity at doses equal to or lower than its analgesic dose. When administered following or concurrent with mu agonist opioid analgesics (e.g., morphine, oxymorphone, fentanyl), nalbuphine may partially reverse or block opioid-induced respiratory depression from the mu agonist analgesic. Nalbuphine may precipitate withdrawal in patients dependent on opioid drugs. Nalbuphine should be used with caution in patients who have been receiving mu opioid analgesics on a regular basis. •Mechanism of action (Drug A): Bupropion is a norepinephrine/dopamine-reuptake inhibitor (NDRI) that exerts its pharmacological effects by weakly inhibiting the enzymes involved in the uptake of the neurotransmitters norepinephrine and dopamine from the synaptic cleft, therefore prolonging their duration of action within the neuronal synapse and the downstream effects of these neurotransmitters. More specifically, bupropion binds to the norepinephrine transporter (NET) and the dopamine transporter (DAT). Bupropion was originally classified as an "atypical" antidepressant because it does not exert the same effects as the classical antidepressants such as Monoamine Oxidase Inhibitors (MAOIs), Tricyclic Antidepressants (TCAs), or Selective Serotonin Reuptake Inhibitors (SSRIs). While it has comparable effectiveness to typical first-line options for the treatment of depression such as SSRIs, bupropion is a unique option for the treatment of MDD as it lacks any clinically relevant serotonergic effects, typical of other mood medications, or any effects on histamine or adrenaline receptors. Lack of activity at these receptors results in a more tolerable side effect profile; bupropion is less likely to cause sexual side effects, sedation, or weight gain as compared to SSRIs or TCAs, for example. When used as an aid to smoking cessation, bupropion is thought to confer its anti-craving and anti-withdrawal effects by inhibiting dopamine reuptake, which is thought to be involved in the reward pathways associated with nicotine, and through the antagonism of the nicotinic acetylcholinergic receptor (AChR), thereby blunting the effects of nicotine. Furthermore, the stimulatory effects produced by bupropion in the central nervous system are similar to nicotine's effects, making low doses of bupropion a suitable option as a nicotine substitute. When used in combination with naltrexone in the marketed product ContraveⓇ for chronic weight management, the two components are thought to have effects on areas of the brain involved in the regulation of food intake. This includes the hypothalamus, which is involved in appetite regulation, and the mesolimbic dopamine circuit, which is involved in reward pathways. Studies have shown that the combined activity of bupropion and naltrexone increase the firing rate of hypothalamic pro-opiomelanocortin (POMC) neurons and blockade of opioid receptor-mediated POMC auto-inhibition, which are associated with a reduction in food intake and increased energy expenditure. This combination was also found to reduce food intake when injected directly into the ventral tegmental area of the mesolimbic circuit in mice, which is an area associated with the regulation of reward pathways. •Mechanism of action (Drug B): The exact mechanism of action is unknown, but is believed to interact with an opiate receptor site in the CNS (probably in or associated with the limbic system). The opiate antagonistic effect may result from competitive inhibition at the opiate receptor, but may also be a result of other mechanisms. Nalbuphine is thought primarily to be a kappa agonist. It is also a partial mu antagonist analgesic, with some binding to the delta receptor and minimal agonist activity at the sigma receptor. •Absorption (Drug A): Bupropion is currently available in 3 distinct, but bioequivalent formulations: immediate release (IR), sustained-release (SR), and extended-release (XL). Immediate Release Formulation In humans, following oral administration of bupropion hydrochloride tablets, peak plasma bupropion concentrations are usually achieved within 2 hours. IR formulations provide a short duration of action and are therefore generally dosed three times per day. Sustained Release Formulation In humans, following oral administration of bupropion hydrochloride sustained-release tablets (SR), peak plasma concentration (Cmax) of bupropion is usually achieved within 3 hours. SR formulations provide a 12-hour extended release of medication and are therefore generally dosed twice per day. Extended Release Formulation Following single oral administration of bupropion hydrochloride extended-release tablets (XL) to healthy volunteers, the median time to peak plasma concentrations for bupropion was approximately 5 hours. The presence of food did not affect the peak concentration or area under the curve of bupropion. XL formulations provide a 24-hour extended release of medication and are therefore generally dosed once per day/ In a trial comparing chronic dosing with bupropion hydrochloride extended-release tablets (SR) 150 mg twice daily to bupropion immediate-release formulation 100 mg 3 times daily, the steady state Cmax for bupropion after bupropion hydrochloride sustained-release tablets (SR) administration was approximately 85% of those achieved after bupropion immediate-release formulation administration. Exposure (AUC) to bupropion was equivalent for both formulations. Bioequivalence was also demonstrated for all three major active metabolites (i.e., hydroxybupropion, threohydrobupropion and erythrohydrobupropion) for both Cmax and AUC. Thus, at steady state, bupropion hydrochloride sustained-release tablets (SR) given twice daily, and the immediate-release formulation of bupropion given 3 times daily, are essentially bioequivalent for both bupropion and the 3 quantitatively important metabolites. Furthermore, in a study comparing 14-day dosing with bupropion hydrochloride extended-release tablets (XL), 300 mg once-daily to the immediate-release formulation of bupropion at 100 mg 3 times daily, equivalence was demonstrated for peak plasma concentration and area under the curve for bupropion and the three metabolites (hydroxybupropion, threohydrobupropion, and erythrohydrobupropion). Additionally, in a study comparing 14-day dosing with bupropion hydrochloride extended-release tablets (XL) 300 mg once daily to the sustained-release formulation of bupropion at 150 mg 2 times daily, equivalence was demonstrated for peak plasma concentration and area under the curve for bupropion and the three metabolites. Bupropion hydrochloride extended-release tablets (SR) can be taken with or without food. Bupropion Cmax and AUC were increased by 11% to 35% and 16% to 19%, respectively, when bupropion hydrochloride extended-release tablets (SR) was administered with food to healthy volunteers in three trials. The food effect is not considered clinically significant. Following a single-dose administration of bupropion hydrochloride extended-release tablets (SR) in humans, Cmax of bupropion's metabolite hydroxybupropion occurs approximately 6 hours post-dose and is approximately 10 times the peak level of the parent drug at steady state. The elimination half-life of hydroxybupropion is approximately 20 (±5) hours and its AUC at steady state is about 17 times that of bupropion. The times to peak concentrations for the erythrohydrobupropion and threohydrobupropion metabolites are similar to that of the hydroxybupropion metabolite. However, their elimination half-lives are longer, 33(±10) and 37 (±13) hours, respectively, and steady-state AUCs are 1.5 and 7 times that of bupropion, respectively. •Absorption (Drug B): The mean absolute bioavailability was 81% and 83% for the 10 and 20 mg intramuscular doses, respectively, and 79% and 76% following 10 and 20 mg of subcutaneous nalbuphine. Clinical studies show that the duration of analgesic activity of the drug can range from 3 to 6 hours. •Volume of distribution (Drug A): No volume of distribution available •Volume of distribution (Drug B): No volume of distribution available •Protein binding (Drug A): In vitro tests show that bupropion is 84% bound to human plasma proteins at concentrations up to 200 mcg per mL. The extent of protein binding of the hydroxybupropion metabolite is similar to that for bupropion, whereas the extent of protein binding of the threohydrobupropion metabolite is about half that seen with bupropion. •Protein binding (Drug B): Not appreciably bound. •Metabolism (Drug A): Bupropion is extensively metabolized in humans. Three metabolites are active: hydroxybupropion, which is formed via hydroxylation of the tert-butyl group of bupropion, and the amino-alcohol isomers, threohydrobupropion and erythrohydrobupropion, which are formed via reduction of the carbonyl group. In vitro findings suggest that CYP2B6 is the principal isoenzyme involved in the formation of hydroxybupropion, while cytochrome P450 enzymes are not involved in the formation of threohydrobupropion. Hydroxybupropion has been shown to have the same affinity as bupropion for the norepinephrine transporter (NET) but approximately 50% of its antidepressant activity despite reaching concentrations of ~10-fold higher than that of the parent drug. Oxidation of the bupropion side chain results in the formation of a glycine conjugate of meta-chlorobenzoic acid, which is then excreted as the major urinary metabolite. The potency and toxicity of the metabolites relative to bupropion have not been fully characterized. However, it has been demonstrated in an antidepressant screening test in mice that hydroxybupropion is one-half as potent as bupropion, while threohydrobupropion and erythrohydrobupropion are 5-fold less potent than bupropion. This may be of clinical importance because the plasma concentrations of the metabolites are as high as or higher than those of bupropion. Bupropion and its metabolites exhibit linear kinetics following chronic administration of 300 to 450 mg per day. •Metabolism (Drug B): No metabolism available •Route of elimination (Drug A): Bupropion is extensively metabolized in humans. Oxidation of the bupropion side chain results in the formation of a glycine conjugate of metachlorobenzoic acid, which is then excreted as the major urinary metabolite. Following oral administration of 200 mg of 14C-bupropion in humans, 87% and 10% of the radioactive dose were recovered in the urine and feces, respectively. However, the fraction of the oral dose of bupropion excreted unchanged was only 0.5%, a finding consistent with the extensive metabolism of bupropion. •Route of elimination (Drug B): No route of elimination available •Half-life (Drug A): 24 hours •Half-life (Drug B): The plasma half-life of nalbuphine is about 5 hours. •Clearance (Drug A): No clearance available •Clearance (Drug B): No clearance available •Toxicity (Drug A): Symptoms of overdose include seizures, hallucinations, loss of consciousness, tachycardia, and cardiac arrest. •Toxicity (Drug B): Oral, acute LD50 is 1100 mg/kg in dog. Symptoms of overdose include primarily sleepiness and mild dysphoria. •Brand Names (Drug A): Aplenzin, Auvelity, Budeprion, Contrave, Forfivo, Wellbutrin, Zyban •Brand Names (Drug B): No brand names available •Synonyms (Drug A): No synonyms listed •Synonyms (Drug B): Nalbufina Nalbuphin Nalbuphine Nalbuphinum •Summary (Drug A): Bupropion is a norepinephrine and dopamine reuptake inhibitor used in the treatment of major depressive disorder (MDD), seasonal affective disorder (SAD), and as an aid to smoking cessation. •Summary (Drug B): Nalbuphine is an opioid agonist-antagonist used to treat pain, for pre and postoperative analgesia, and for analgesia in labor and delivery.

Central nervous system (CNS) depressants can cause sedation, falls, respiratory depression, coma, and death.2,3 The potential interaction between a CNS depressant and another CNS depressant drug due to synergistic effects is well documented in the literature, although the risk and severity of CNS depression vary from each drug. The subject and affected drugs are both CNS depressants that, when co-administered, may result in a more profound CNS depression. As the risk and severity of CNS depression resulting from the combined use of CNS depressants vary from each agent, each interaction between CNS depressants should be considered individually. The severity of the interaction is moderate.

Question: Does Bupropion and Nalbuphine interact? Information: •Drug A: Bupropion •Drug B: Nalbuphine •Severity: MODERATE •Description: The risk or severity of CNS depression can be increased when Nalbuphine is combined with Bupropion. •Extended Description: Central nervous system (CNS) depressants can cause sedation, falls, respiratory depression, coma, and death.2,3 The potential interaction between a CNS depressant and another CNS depressant drug due to synergistic effects is well documented in the literature, although the risk and severity of CNS depression vary from each drug. The subject and affected drugs are both CNS depressants that, when co-administered, may result in a more profound CNS depression. As the risk and severity of CNS depression resulting from the combined use of CNS depressants vary from each agent, each interaction between CNS depressants should be considered individually. •Indication (Drug A): Bupropion is indicated for the treatment of major depressive disorder (MDD), seasonal affective disorder (SAD), and as an aid to smoking cessation. When used in combination with naltrexone as the marketed product ContraveⓇ, bupropion is indicated as an adjunct to a reduced-calorie diet and increased physical activity for chronic weight management in adults with an initial body mass index (BMI) of: 30 kg/m^2 or greater (obese) or 27 kg/m^2 or greater (overweight) in the presence of at least one weight-related comorbid condition (e.g., hypertension, type 2 diabetes mellitus, or dyslipidemia). Bupropion is also used off-label as a first-line treatment in patients with ADHD and comorbid bipolar disorder when used as an adjunct to mood stabilizers. •Indication (Drug B): For the relief of moderate to severe pain. •Pharmacodynamics (Drug A): Bupropion is chemically unrelated to tricyclic, tetracyclic, selective serotonin re-uptake inhibitors, or other known antidepressant agents. Compared to classical tricyclic antidepressants, Bupropion is a relatively weak inhibitor of the neuronal uptake of norepinephrine and dopamine. In addition, Bupropion does not inhibit monoamine oxidase. Bupropion has been found to be essentially inactive at the serotonin transporter (SERT)(IC50 >10 000 nM), however both bupropion and its primary metabolite hydroxybupropion have been found to block the function of cation-selective serotonin type 3A receptors (5-HT3ARs). Bupropion produces dose-related central nervous system (CNS) stimulant effects in animals, as evidenced by increased locomotor activity, increased rates of responding in various schedule-controlled operant behaviour tasks, and, at high doses, induction of mild stereotyped behaviour. Due to these stimulant effects and selective activity at dopamine and norepinephrine receptors, bupropion has been identified as having an abuse potential. Bupropion has a similar structure to the controlled substance Cathinone, and has been identified as having mild amphetamine-like activity, particularly when inhaled or injected. Bupropion is also known to lower the seizure threshold, making any pre-existing seizure conditions a contraindication to its use. This risk is exacerbated when bupropion is combined with other drugs or substances that lower the seizure threshold, such as cocaine, or in clinical situations that would increase the risk of a seizure such as abrupt alcohol or benzodiazepine withdrawal. As norepinephrine has been shown to have anticonvulsant properties, bupropion's inhibitory effects on NET are thought to contribute to its pro-convulsant activity. Bupropion has been shown to increase blood pressure and pose a risk for exacerbation of unmanaged or pre-existing hypertension, however, clinical trials of bupropion in smokers with CVD have not identified an increased incidence of CV events including stroke or heart attack. In clinical trials, the mean increase in systolic blood pressure associated with the use of bupropion was found to be 1.3 mmHg. •Pharmacodynamics (Drug B): Nalbuphine is a synthetic opioid agonist-antagonist analgesic of the phenanthrene series. Nalbuphine's analgesic potency is essentially equivalent to that of morphine on a milligram basis. The opoioid antagonist activity of nalbuphine is about one-fourth to that of nalorphine and 10 times to that of pentazocine. Nalbuphine by itself has potent opioid antagonist activity at doses equal to or lower than its analgesic dose. When administered following or concurrent with mu agonist opioid analgesics (e.g., morphine, oxymorphone, fentanyl), nalbuphine may partially reverse or block opioid-induced respiratory depression from the mu agonist analgesic. Nalbuphine may precipitate withdrawal in patients dependent on opioid drugs. Nalbuphine should be used with caution in patients who have been receiving mu opioid analgesics on a regular basis. •Mechanism of action (Drug A): Bupropion is a norepinephrine/dopamine-reuptake inhibitor (NDRI) that exerts its pharmacological effects by weakly inhibiting the enzymes involved in the uptake of the neurotransmitters norepinephrine and dopamine from the synaptic cleft, therefore prolonging their duration of action within the neuronal synapse and the downstream effects of these neurotransmitters. More specifically, bupropion binds to the norepinephrine transporter (NET) and the dopamine transporter (DAT). Bupropion was originally classified as an "atypical" antidepressant because it does not exert the same effects as the classical antidepressants such as Monoamine Oxidase Inhibitors (MAOIs), Tricyclic Antidepressants (TCAs), or Selective Serotonin Reuptake Inhibitors (SSRIs). While it has comparable effectiveness to typical first-line options for the treatment of depression such as SSRIs, bupropion is a unique option for the treatment of MDD as it lacks any clinically relevant serotonergic effects, typical of other mood medications, or any effects on histamine or adrenaline receptors. Lack of activity at these receptors results in a more tolerable side effect profile; bupropion is less likely to cause sexual side effects, sedation, or weight gain as compared to SSRIs or TCAs, for example. When used as an aid to smoking cessation, bupropion is thought to confer its anti-craving and anti-withdrawal effects by inhibiting dopamine reuptake, which is thought to be involved in the reward pathways associated with nicotine, and through the antagonism of the nicotinic acetylcholinergic receptor (AChR), thereby blunting the effects of nicotine. Furthermore, the stimulatory effects produced by bupropion in the central nervous system are similar to nicotine's effects, making low doses of bupropion a suitable option as a nicotine substitute. When used in combination with naltrexone in the marketed product ContraveⓇ for chronic weight management, the two components are thought to have effects on areas of the brain involved in the regulation of food intake. This includes the hypothalamus, which is involved in appetite regulation, and the mesolimbic dopamine circuit, which is involved in reward pathways. Studies have shown that the combined activity of bupropion and naltrexone increase the firing rate of hypothalamic pro-opiomelanocortin (POMC) neurons and blockade of opioid receptor-mediated POMC auto-inhibition, which are associated with a reduction in food intake and increased energy expenditure. This combination was also found to reduce food intake when injected directly into the ventral tegmental area of the mesolimbic circuit in mice, which is an area associated with the regulation of reward pathways. •Mechanism of action (Drug B): The exact mechanism of action is unknown, but is believed to interact with an opiate receptor site in the CNS (probably in or associated with the limbic system). The opiate antagonistic effect may result from competitive inhibition at the opiate receptor, but may also be a result of other mechanisms. Nalbuphine is thought primarily to be a kappa agonist. It is also a partial mu antagonist analgesic, with some binding to the delta receptor and minimal agonist activity at the sigma receptor. •Absorption (Drug A): Bupropion is currently available in 3 distinct, but bioequivalent formulations: immediate release (IR), sustained-release (SR), and extended-release (XL). Immediate Release Formulation In humans, following oral administration of bupropion hydrochloride tablets, peak plasma bupropion concentrations are usually achieved within 2 hours. IR formulations provide a short duration of action and are therefore generally dosed three times per day. Sustained Release Formulation In humans, following oral administration of bupropion hydrochloride sustained-release tablets (SR), peak plasma concentration (Cmax) of bupropion is usually achieved within 3 hours. SR formulations provide a 12-hour extended release of medication and are therefore generally dosed twice per day. Extended Release Formulation Following single oral administration of bupropion hydrochloride extended-release tablets (XL) to healthy volunteers, the median time to peak plasma concentrations for bupropion was approximately 5 hours. The presence of food did not affect the peak concentration or area under the curve of bupropion. XL formulations provide a 24-hour extended release of medication and are therefore generally dosed once per day/ In a trial comparing chronic dosing with bupropion hydrochloride extended-release tablets (SR) 150 mg twice daily to bupropion immediate-release formulation 100 mg 3 times daily, the steady state Cmax for bupropion after bupropion hydrochloride sustained-release tablets (SR) administration was approximately 85% of those achieved after bupropion immediate-release formulation administration. Exposure (AUC) to bupropion was equivalent for both formulations. Bioequivalence was also demonstrated for all three major active metabolites (i.e., hydroxybupropion, threohydrobupropion and erythrohydrobupropion) for both Cmax and AUC. Thus, at steady state, bupropion hydrochloride sustained-release tablets (SR) given twice daily, and the immediate-release formulation of bupropion given 3 times daily, are essentially bioequivalent for both bupropion and the 3 quantitatively important metabolites. Furthermore, in a study comparing 14-day dosing with bupropion hydrochloride extended-release tablets (XL), 300 mg once-daily to the immediate-release formulation of bupropion at 100 mg 3 times daily, equivalence was demonstrated for peak plasma concentration and area under the curve for bupropion and the three metabolites (hydroxybupropion, threohydrobupropion, and erythrohydrobupropion). Additionally, in a study comparing 14-day dosing with bupropion hydrochloride extended-release tablets (XL) 300 mg once daily to the sustained-release formulation of bupropion at 150 mg 2 times daily, equivalence was demonstrated for peak plasma concentration and area under the curve for bupropion and the three metabolites. Bupropion hydrochloride extended-release tablets (SR) can be taken with or without food. Bupropion Cmax and AUC were increased by 11% to 35% and 16% to 19%, respectively, when bupropion hydrochloride extended-release tablets (SR) was administered with food to healthy volunteers in three trials. The food effect is not considered clinically significant. Following a single-dose administration of bupropion hydrochloride extended-release tablets (SR) in humans, Cmax of bupropion's metabolite hydroxybupropion occurs approximately 6 hours post-dose and is approximately 10 times the peak level of the parent drug at steady state. The elimination half-life of hydroxybupropion is approximately 20 (±5) hours and its AUC at steady state is about 17 times that of bupropion. The times to peak concentrations for the erythrohydrobupropion and threohydrobupropion metabolites are similar to that of the hydroxybupropion metabolite. However, their elimination half-lives are longer, 33(±10) and 37 (±13) hours, respectively, and steady-state AUCs are 1.5 and 7 times that of bupropion, respectively. •Absorption (Drug B): The mean absolute bioavailability was 81% and 83% for the 10 and 20 mg intramuscular doses, respectively, and 79% and 76% following 10 and 20 mg of subcutaneous nalbuphine. Clinical studies show that the duration of analgesic activity of the drug can range from 3 to 6 hours. •Volume of distribution (Drug A): No volume of distribution available •Volume of distribution (Drug B): No volume of distribution available •Protein binding (Drug A): In vitro tests show that bupropion is 84% bound to human plasma proteins at concentrations up to 200 mcg per mL. The extent of protein binding of the hydroxybupropion metabolite is similar to that for bupropion, whereas the extent of protein binding of the threohydrobupropion metabolite is about half that seen with bupropion. •Protein binding (Drug B): Not appreciably bound. •Metabolism (Drug A): Bupropion is extensively metabolized in humans. Three metabolites are active: hydroxybupropion, which is formed via hydroxylation of the tert-butyl group of bupropion, and the amino-alcohol isomers, threohydrobupropion and erythrohydrobupropion, which are formed via reduction of the carbonyl group. In vitro findings suggest that CYP2B6 is the principal isoenzyme involved in the formation of hydroxybupropion, while cytochrome P450 enzymes are not involved in the formation of threohydrobupropion. Hydroxybupropion has been shown to have the same affinity as bupropion for the norepinephrine transporter (NET) but approximately 50% of its antidepressant activity despite reaching concentrations of ~10-fold higher than that of the parent drug. Oxidation of the bupropion side chain results in the formation of a glycine conjugate of meta-chlorobenzoic acid, which is then excreted as the major urinary metabolite. The potency and toxicity of the metabolites relative to bupropion have not been fully characterized. However, it has been demonstrated in an antidepressant screening test in mice that hydroxybupropion is one-half as potent as bupropion, while threohydrobupropion and erythrohydrobupropion are 5-fold less potent than bupropion. This may be of clinical importance because the plasma concentrations of the metabolites are as high as or higher than those of bupropion. Bupropion and its metabolites exhibit linear kinetics following chronic administration of 300 to 450 mg per day. •Metabolism (Drug B): No metabolism available •Route of elimination (Drug A): Bupropion is extensively metabolized in humans. Oxidation of the bupropion side chain results in the formation of a glycine conjugate of metachlorobenzoic acid, which is then excreted as the major urinary metabolite. Following oral administration of 200 mg of 14C-bupropion in humans, 87% and 10% of the radioactive dose were recovered in the urine and feces, respectively. However, the fraction of the oral dose of bupropion excreted unchanged was only 0.5%, a finding consistent with the extensive metabolism of bupropion. •Route of elimination (Drug B): No route of elimination available •Half-life (Drug A): 24 hours •Half-life (Drug B): The plasma half-life of nalbuphine is about 5 hours. •Clearance (Drug A): No clearance available •Clearance (Drug B): No clearance available •Toxicity (Drug A): Symptoms of overdose include seizures, hallucinations, loss of consciousness, tachycardia, and cardiac arrest. •Toxicity (Drug B): Oral, acute LD50 is 1100 mg/kg in dog. Symptoms of overdose include primarily sleepiness and mild dysphoria. •Brand Names (Drug A): Aplenzin, Auvelity, Budeprion, Contrave, Forfivo, Wellbutrin, Zyban •Brand Names (Drug B): No brand names available •Synonyms (Drug A): No synonyms listed •Synonyms (Drug B): Nalbufina Nalbuphin Nalbuphine Nalbuphinum •Summary (Drug A): Bupropion is a norepinephrine and dopamine reuptake inhibitor used in the treatment of major depressive disorder (MDD), seasonal affective disorder (SAD), and as an aid to smoking cessation. •Summary (Drug B): Nalbuphine is an opioid agonist-antagonist used to treat pain, for pre and postoperative analgesia, and for analgesia in labor and delivery. Output: Central nervous system (CNS) depressants can cause sedation, falls, respiratory depression, coma, and death.2,3 The potential interaction between a CNS depressant and another CNS depressant drug due to synergistic effects is well documented in the literature, although the risk and severity of CNS depression vary from each drug. The subject and affected drugs are both CNS depressants that, when co-administered, may result in a more profound CNS depression. As the risk and severity of CNS depression resulting from the combined use of CNS depressants vary from each agent, each interaction between CNS depressants should be considered individually. The severity of the interaction is moderate.

Does Bupropion and Naldemedine interact?

•Drug A: Bupropion •Drug B: Naldemedine •Severity: MINOR •Description: Bupropion may decrease the excretion rate of Naldemedine which could result in a higher serum level. •Extended Description: The renal excretion of drugs is the overall result of a combination of kidney processes that include glomerular filtration, passive diffusion, tubular secretion, and tubular reabsorption. Since two of these mechanisms - tubular secretion and reabsorption - are saturable processes , they are consequently susceptible to competition between multiple substrates excreted by the kidneys. If two or more medications that are mainly renally excreted are co-administered, they may compete for renal elimination; there is a large likelihood that one agent may "out-compete" or saturate the renal excretion mechanisms before the other concomitantly administered agent(s) are excreted. As a result, the elimination of these other concurrently administered agents may be inhibited or otherwise delayed, which could lead to increases in their serum concentrations and the risk, incidence, and/or severity of adverse effects associated with the exposure to such drugs. •Indication (Drug A): Bupropion is indicated for the treatment of major depressive disorder (MDD), seasonal affective disorder (SAD), and as an aid to smoking cessation. When used in combination with naltrexone as the marketed product ContraveⓇ, bupropion is indicated as an adjunct to a reduced-calorie diet and increased physical activity for chronic weight management in adults with an initial body mass index (BMI) of: 30 kg/m^2 or greater (obese) or 27 kg/m^2 or greater (overweight) in the presence of at least one weight-related comorbid condition (e.g., hypertension, type 2 diabetes mellitus, or dyslipidemia). Bupropion is also used off-label as a first-line treatment in patients with ADHD and comorbid bipolar disorder when used as an adjunct to mood stabilizers. •Indication (Drug B): For the treatment of opioid-induced constipation. •Pharmacodynamics (Drug A): Bupropion is chemically unrelated to tricyclic, tetracyclic, selective serotonin re-uptake inhibitors, or other known antidepressant agents. Compared to classical tricyclic antidepressants, Bupropion is a relatively weak inhibitor of the neuronal uptake of norepinephrine and dopamine. In addition, Bupropion does not inhibit monoamine oxidase. Bupropion has been found to be essentially inactive at the serotonin transporter (SERT)(IC50 >10 000 nM), however both bupropion and its primary metabolite hydroxybupropion have been found to block the function of cation-selective serotonin type 3A receptors (5-HT3ARs). Bupropion produces dose-related central nervous system (CNS) stimulant effects in animals, as evidenced by increased locomotor activity, increased rates of responding in various schedule-controlled operant behaviour tasks, and, at high doses, induction of mild stereotyped behaviour. Due to these stimulant effects and selective activity at dopamine and norepinephrine receptors, bupropion has been identified as having an abuse potential. Bupropion has a similar structure to the controlled substance Cathinone, and has been identified as having mild amphetamine-like activity, particularly when inhaled or injected. Bupropion is also known to lower the seizure threshold, making any pre-existing seizure conditions a contraindication to its use. This risk is exacerbated when bupropion is combined with other drugs or substances that lower the seizure threshold, such as cocaine, or in clinical situations that would increase the risk of a seizure such as abrupt alcohol or benzodiazepine withdrawal. As norepinephrine has been shown to have anticonvulsant properties, bupropion's inhibitory effects on NET are thought to contribute to its pro-convulsant activity. Bupropion has been shown to increase blood pressure and pose a risk for exacerbation of unmanaged or pre-existing hypertension, however, clinical trials of bupropion in smokers with CVD have not identified an increased incidence of CV events including stroke or heart attack. In clinical trials, the mean increase in systolic blood pressure associated with the use of bupropion was found to be 1.3 mmHg. •Pharmacodynamics (Drug B): Naldemedine is an opioid receptor antagonist with restricted movement across the blood brain barrier. This allows it to antagonize the periperal effects of opioid drugs such as constipation without interfering with the effects on the central nervous system. •Mechanism of action (Drug A): Bupropion is a norepinephrine/dopamine-reuptake inhibitor (NDRI) that exerts its pharmacological effects by weakly inhibiting the enzymes involved in the uptake of the neurotransmitters norepinephrine and dopamine from the synaptic cleft, therefore prolonging their duration of action within the neuronal synapse and the downstream effects of these neurotransmitters. More specifically, bupropion binds to the norepinephrine transporter (NET) and the dopamine transporter (DAT). Bupropion was originally classified as an "atypical" antidepressant because it does not exert the same effects as the classical antidepressants such as Monoamine Oxidase Inhibitors (MAOIs), Tricyclic Antidepressants (TCAs), or Selective Serotonin Reuptake Inhibitors (SSRIs). While it has comparable effectiveness to typical first-line options for the treatment of depression such as SSRIs, bupropion is a unique option for the treatment of MDD as it lacks any clinically relevant serotonergic effects, typical of other mood medications, or any effects on histamine or adrenaline receptors. Lack of activity at these receptors results in a more tolerable side effect profile; bupropion is less likely to cause sexual side effects, sedation, or weight gain as compared to SSRIs or TCAs, for example. When used as an aid to smoking cessation, bupropion is thought to confer its anti-craving and anti-withdrawal effects by inhibiting dopamine reuptake, which is thought to be involved in the reward pathways associated with nicotine, and through the antagonism of the nicotinic acetylcholinergic receptor (AChR), thereby blunting the effects of nicotine. Furthermore, the stimulatory effects produced by bupropion in the central nervous system are similar to nicotine's effects, making low doses of bupropion a suitable option as a nicotine substitute. When used in combination with naltrexone in the marketed product ContraveⓇ for chronic weight management, the two components are thought to have effects on areas of the brain involved in the regulation of food intake. This includes the hypothalamus, which is involved in appetite regulation, and the mesolimbic dopamine circuit, which is involved in reward pathways. Studies have shown that the combined activity of bupropion and naltrexone increase the firing rate of hypothalamic pro-opiomelanocortin (POMC) neurons and blockade of opioid receptor-mediated POMC auto-inhibition, which are associated with a reduction in food intake and increased energy expenditure. This combination was also found to reduce food intake when injected directly into the ventral tegmental area of the mesolimbic circuit in mice, which is an area associated with the regulation of reward pathways. •Mechanism of action (Drug B): Naldemedine binds to and antagonizes mu-, delta-, and kappa-opioid receptors. The binding of opioid agonists to peripheral mu-opioid receptors slows the transit of feces through the intestine resulting in constipation. By antagonizing mu-opioid receptors, naldemedine inhibits this effect. •Absorption (Drug A): Bupropion is currently available in 3 distinct, but bioequivalent formulations: immediate release (IR), sustained-release (SR), and extended-release (XL). Immediate Release Formulation In humans, following oral administration of bupropion hydrochloride tablets, peak plasma bupropion concentrations are usually achieved within 2 hours. IR formulations provide a short duration of action and are therefore generally dosed three times per day. Sustained Release Formulation In humans, following oral administration of bupropion hydrochloride sustained-release tablets (SR), peak plasma concentration (Cmax) of bupropion is usually achieved within 3 hours. SR formulations provide a 12-hour extended release of medication and are therefore generally dosed twice per day. Extended Release Formulation Following single oral administration of bupropion hydrochloride extended-release tablets (XL) to healthy volunteers, the median time to peak plasma concentrations for bupropion was approximately 5 hours. The presence of food did not affect the peak concentration or area under the curve of bupropion. XL formulations provide a 24-hour extended release of medication and are therefore generally dosed once per day/ In a trial comparing chronic dosing with bupropion hydrochloride extended-release tablets (SR) 150 mg twice daily to bupropion immediate-release formulation 100 mg 3 times daily, the steady state Cmax for bupropion after bupropion hydrochloride sustained-release tablets (SR) administration was approximately 85% of those achieved after bupropion immediate-release formulation administration. Exposure (AUC) to bupropion was equivalent for both formulations. Bioequivalence was also demonstrated for all three major active metabolites (i.e., hydroxybupropion, threohydrobupropion and erythrohydrobupropion) for both Cmax and AUC. Thus, at steady state, bupropion hydrochloride sustained-release tablets (SR) given twice daily, and the immediate-release formulation of bupropion given 3 times daily, are essentially bioequivalent for both bupropion and the 3 quantitatively important metabolites. Furthermore, in a study comparing 14-day dosing with bupropion hydrochloride extended-release tablets (XL), 300 mg once-daily to the immediate-release formulation of bupropion at 100 mg 3 times daily, equivalence was demonstrated for peak plasma concentration and area under the curve for bupropion and the three metabolites (hydroxybupropion, threohydrobupropion, and erythrohydrobupropion). Additionally, in a study comparing 14-day dosing with bupropion hydrochloride extended-release tablets (XL) 300 mg once daily to the sustained-release formulation of bupropion at 150 mg 2 times daily, equivalence was demonstrated for peak plasma concentration and area under the curve for bupropion and the three metabolites. Bupropion hydrochloride extended-release tablets (SR) can be taken with or without food. Bupropion Cmax and AUC were increased by 11% to 35% and 16% to 19%, respectively, when bupropion hydrochloride extended-release tablets (SR) was administered with food to healthy volunteers in three trials. The food effect is not considered clinically significant. Following a single-dose administration of bupropion hydrochloride extended-release tablets (SR) in humans, Cmax of bupropion's metabolite hydroxybupropion occurs approximately 6 hours post-dose and is approximately 10 times the peak level of the parent drug at steady state. The elimination half-life of hydroxybupropion is approximately 20 (±5) hours and its AUC at steady state is about 17 times that of bupropion. The times to peak concentrations for the erythrohydrobupropion and threohydrobupropion metabolites are similar to that of the hydroxybupropion metabolite. However, their elimination half-lives are longer, 33(±10) and 37 (±13) hours, respectively, and steady-state AUCs are 1.5 and 7 times that of bupropion, respectively. •Absorption (Drug B): Tmax is 0.75 h. Administration with a high-fat meal reduces Cmax by 35% and increases Tmax to 2.5 h. •Volume of distribution (Drug A): No volume of distribution available •Volume of distribution (Drug B): The apparent volume of disribution during the terminal phase is 155 L •Protein binding (Drug A): In vitro tests show that bupropion is 84% bound to human plasma proteins at concentrations up to 200 mcg per mL. The extent of protein binding of the hydroxybupropion metabolite is similar to that for bupropion, whereas the extent of protein binding of the threohydrobupropion metabolite is about half that seen with bupropion. •Protein binding (Drug B): Naldemedine is 93-94% bound to human plasma proteins. •Metabolism (Drug A): Bupropion is extensively metabolized in humans. Three metabolites are active: hydroxybupropion, which is formed via hydroxylation of the tert-butyl group of bupropion, and the amino-alcohol isomers, threohydrobupropion and erythrohydrobupropion, which are formed via reduction of the carbonyl group. In vitro findings suggest that CYP2B6 is the principal isoenzyme involved in the formation of hydroxybupropion, while cytochrome P450 enzymes are not involved in the formation of threohydrobupropion. Hydroxybupropion has been shown to have the same affinity as bupropion for the norepinephrine transporter (NET) but approximately 50% of its antidepressant activity despite reaching concentrations of ~10-fold higher than that of the parent drug. Oxidation of the bupropion side chain results in the formation of a glycine conjugate of meta-chlorobenzoic acid, which is then excreted as the major urinary metabolite. The potency and toxicity of the metabolites relative to bupropion have not been fully characterized. However, it has been demonstrated in an antidepressant screening test in mice that hydroxybupropion is one-half as potent as bupropion, while threohydrobupropion and erythrohydrobupropion are 5-fold less potent than bupropion. This may be of clinical importance because the plasma concentrations of the metabolites are as high as or higher than those of bupropion. Bupropion and its metabolites exhibit linear kinetics following chronic administration of 300 to 450 mg per day. •Metabolism (Drug B): Naldemedine is mainly metabolized to nor-naldemedine by CYP3A. Some metabolism to naldemedine-3-glucuronide occurs via UGT1A3. Both metabolites are acitive but less potent than naldemedine. The relative exposures of these metabolites are 9-13% and <3% for nor-naldemedine and naldemedine-3-glucuronide respectively. Naldemedine is also cleaved in the intestine to form benzamidine and naldemedine carboxylic acid. •Route of elimination (Drug A): Bupropion is extensively metabolized in humans. Oxidation of the bupropion side chain results in the formation of a glycine conjugate of metachlorobenzoic acid, which is then excreted as the major urinary metabolite. Following oral administration of 200 mg of 14C-bupropion in humans, 87% and 10% of the radioactive dose were recovered in the urine and feces, respectively. However, the fraction of the oral dose of bupropion excreted unchanged was only 0.5%, a finding consistent with the extensive metabolism of bupropion. •Route of elimination (Drug B): 57% of naldemedine is excreted in the urine with 16-18% as the parent compound and 35% is excreted in the feces. •Half-life (Drug A): 24 hours •Half-life (Drug B): The terminal elimination half life is 11 h. •Clearance (Drug A): No clearance available •Clearance (Drug B): No clearance available •Toxicity (Drug A): Symptoms of overdose include seizures, hallucinations, loss of consciousness, tachycardia, and cardiac arrest. •Toxicity (Drug B): The most common adverse effects of naldemedine are abdominal pain (11%), diarrhea (7%), nausea (6%), vomiting (3%), and gastroenteritis (3%). •Brand Names (Drug A): Aplenzin, Auvelity, Budeprion, Contrave, Forfivo, Wellbutrin, Zyban •Brand Names (Drug B): Symproic •Synonyms (Drug A): No synonyms listed •Synonyms (Drug B): No synonyms listed •Summary (Drug A): Bupropion is a norepinephrine and dopamine reuptake inhibitor used in the treatment of major depressive disorder (MDD), seasonal affective disorder (SAD), and as an aid to smoking cessation. •Summary (Drug B): Naldemedine is an opioid antagonist used to to treat opioid-induced constipation.

The renal excretion of drugs is the overall result of a combination of kidney processes that include glomerular filtration, passive diffusion, tubular secretion, and tubular reabsorption. Since two of these mechanisms - tubular secretion and reabsorption - are saturable processes , they are consequently susceptible to competition between multiple substrates excreted by the kidneys. If two or more medications that are mainly renally excreted are co-administered, they may compete for renal elimination; there is a large likelihood that one agent may "out-compete" or saturate the renal excretion mechanisms before the other concomitantly administered agent(s) are excreted. As a result, the elimination of these other concurrently administered agents may be inhibited or otherwise delayed, which could lead to increases in their serum concentrations and the risk, incidence, and/or severity of adverse effects associated with the exposure to such drugs. The severity of the interaction is minor.

Question: Does Bupropion and Naldemedine interact? Information: •Drug A: Bupropion •Drug B: Naldemedine •Severity: MINOR •Description: Bupropion may decrease the excretion rate of Naldemedine which could result in a higher serum level. •Extended Description: The renal excretion of drugs is the overall result of a combination of kidney processes that include glomerular filtration, passive diffusion, tubular secretion, and tubular reabsorption. Since two of these mechanisms - tubular secretion and reabsorption - are saturable processes , they are consequently susceptible to competition between multiple substrates excreted by the kidneys. If two or more medications that are mainly renally excreted are co-administered, they may compete for renal elimination; there is a large likelihood that one agent may "out-compete" or saturate the renal excretion mechanisms before the other concomitantly administered agent(s) are excreted. As a result, the elimination of these other concurrently administered agents may be inhibited or otherwise delayed, which could lead to increases in their serum concentrations and the risk, incidence, and/or severity of adverse effects associated with the exposure to such drugs. •Indication (Drug A): Bupropion is indicated for the treatment of major depressive disorder (MDD), seasonal affective disorder (SAD), and as an aid to smoking cessation. When used in combination with naltrexone as the marketed product ContraveⓇ, bupropion is indicated as an adjunct to a reduced-calorie diet and increased physical activity for chronic weight management in adults with an initial body mass index (BMI) of: 30 kg/m^2 or greater (obese) or 27 kg/m^2 or greater (overweight) in the presence of at least one weight-related comorbid condition (e.g., hypertension, type 2 diabetes mellitus, or dyslipidemia). Bupropion is also used off-label as a first-line treatment in patients with ADHD and comorbid bipolar disorder when used as an adjunct to mood stabilizers. •Indication (Drug B): For the treatment of opioid-induced constipation. •Pharmacodynamics (Drug A): Bupropion is chemically unrelated to tricyclic, tetracyclic, selective serotonin re-uptake inhibitors, or other known antidepressant agents. Compared to classical tricyclic antidepressants, Bupropion is a relatively weak inhibitor of the neuronal uptake of norepinephrine and dopamine. In addition, Bupropion does not inhibit monoamine oxidase. Bupropion has been found to be essentially inactive at the serotonin transporter (SERT)(IC50 >10 000 nM), however both bupropion and its primary metabolite hydroxybupropion have been found to block the function of cation-selective serotonin type 3A receptors (5-HT3ARs). Bupropion produces dose-related central nervous system (CNS) stimulant effects in animals, as evidenced by increased locomotor activity, increased rates of responding in various schedule-controlled operant behaviour tasks, and, at high doses, induction of mild stereotyped behaviour. Due to these stimulant effects and selective activity at dopamine and norepinephrine receptors, bupropion has been identified as having an abuse potential. Bupropion has a similar structure to the controlled substance Cathinone, and has been identified as having mild amphetamine-like activity, particularly when inhaled or injected. Bupropion is also known to lower the seizure threshold, making any pre-existing seizure conditions a contraindication to its use. This risk is exacerbated when bupropion is combined with other drugs or substances that lower the seizure threshold, such as cocaine, or in clinical situations that would increase the risk of a seizure such as abrupt alcohol or benzodiazepine withdrawal. As norepinephrine has been shown to have anticonvulsant properties, bupropion's inhibitory effects on NET are thought to contribute to its pro-convulsant activity. Bupropion has been shown to increase blood pressure and pose a risk for exacerbation of unmanaged or pre-existing hypertension, however, clinical trials of bupropion in smokers with CVD have not identified an increased incidence of CV events including stroke or heart attack. In clinical trials, the mean increase in systolic blood pressure associated with the use of bupropion was found to be 1.3 mmHg. •Pharmacodynamics (Drug B): Naldemedine is an opioid receptor antagonist with restricted movement across the blood brain barrier. This allows it to antagonize the periperal effects of opioid drugs such as constipation without interfering with the effects on the central nervous system. •Mechanism of action (Drug A): Bupropion is a norepinephrine/dopamine-reuptake inhibitor (NDRI) that exerts its pharmacological effects by weakly inhibiting the enzymes involved in the uptake of the neurotransmitters norepinephrine and dopamine from the synaptic cleft, therefore prolonging their duration of action within the neuronal synapse and the downstream effects of these neurotransmitters. More specifically, bupropion binds to the norepinephrine transporter (NET) and the dopamine transporter (DAT). Bupropion was originally classified as an "atypical" antidepressant because it does not exert the same effects as the classical antidepressants such as Monoamine Oxidase Inhibitors (MAOIs), Tricyclic Antidepressants (TCAs), or Selective Serotonin Reuptake Inhibitors (SSRIs). While it has comparable effectiveness to typical first-line options for the treatment of depression such as SSRIs, bupropion is a unique option for the treatment of MDD as it lacks any clinically relevant serotonergic effects, typical of other mood medications, or any effects on histamine or adrenaline receptors. Lack of activity at these receptors results in a more tolerable side effect profile; bupropion is less likely to cause sexual side effects, sedation, or weight gain as compared to SSRIs or TCAs, for example. When used as an aid to smoking cessation, bupropion is thought to confer its anti-craving and anti-withdrawal effects by inhibiting dopamine reuptake, which is thought to be involved in the reward pathways associated with nicotine, and through the antagonism of the nicotinic acetylcholinergic receptor (AChR), thereby blunting the effects of nicotine. Furthermore, the stimulatory effects produced by bupropion in the central nervous system are similar to nicotine's effects, making low doses of bupropion a suitable option as a nicotine substitute. When used in combination with naltrexone in the marketed product ContraveⓇ for chronic weight management, the two components are thought to have effects on areas of the brain involved in the regulation of food intake. This includes the hypothalamus, which is involved in appetite regulation, and the mesolimbic dopamine circuit, which is involved in reward pathways. Studies have shown that the combined activity of bupropion and naltrexone increase the firing rate of hypothalamic pro-opiomelanocortin (POMC) neurons and blockade of opioid receptor-mediated POMC auto-inhibition, which are associated with a reduction in food intake and increased energy expenditure. This combination was also found to reduce food intake when injected directly into the ventral tegmental area of the mesolimbic circuit in mice, which is an area associated with the regulation of reward pathways. •Mechanism of action (Drug B): Naldemedine binds to and antagonizes mu-, delta-, and kappa-opioid receptors. The binding of opioid agonists to peripheral mu-opioid receptors slows the transit of feces through the intestine resulting in constipation. By antagonizing mu-opioid receptors, naldemedine inhibits this effect. •Absorption (Drug A): Bupropion is currently available in 3 distinct, but bioequivalent formulations: immediate release (IR), sustained-release (SR), and extended-release (XL). Immediate Release Formulation In humans, following oral administration of bupropion hydrochloride tablets, peak plasma bupropion concentrations are usually achieved within 2 hours. IR formulations provide a short duration of action and are therefore generally dosed three times per day. Sustained Release Formulation In humans, following oral administration of bupropion hydrochloride sustained-release tablets (SR), peak plasma concentration (Cmax) of bupropion is usually achieved within 3 hours. SR formulations provide a 12-hour extended release of medication and are therefore generally dosed twice per day. Extended Release Formulation Following single oral administration of bupropion hydrochloride extended-release tablets (XL) to healthy volunteers, the median time to peak plasma concentrations for bupropion was approximately 5 hours. The presence of food did not affect the peak concentration or area under the curve of bupropion. XL formulations provide a 24-hour extended release of medication and are therefore generally dosed once per day/ In a trial comparing chronic dosing with bupropion hydrochloride extended-release tablets (SR) 150 mg twice daily to bupropion immediate-release formulation 100 mg 3 times daily, the steady state Cmax for bupropion after bupropion hydrochloride sustained-release tablets (SR) administration was approximately 85% of those achieved after bupropion immediate-release formulation administration. Exposure (AUC) to bupropion was equivalent for both formulations. Bioequivalence was also demonstrated for all three major active metabolites (i.e., hydroxybupropion, threohydrobupropion and erythrohydrobupropion) for both Cmax and AUC. Thus, at steady state, bupropion hydrochloride sustained-release tablets (SR) given twice daily, and the immediate-release formulation of bupropion given 3 times daily, are essentially bioequivalent for both bupropion and the 3 quantitatively important metabolites. Furthermore, in a study comparing 14-day dosing with bupropion hydrochloride extended-release tablets (XL), 300 mg once-daily to the immediate-release formulation of bupropion at 100 mg 3 times daily, equivalence was demonstrated for peak plasma concentration and area under the curve for bupropion and the three metabolites (hydroxybupropion, threohydrobupropion, and erythrohydrobupropion). Additionally, in a study comparing 14-day dosing with bupropion hydrochloride extended-release tablets (XL) 300 mg once daily to the sustained-release formulation of bupropion at 150 mg 2 times daily, equivalence was demonstrated for peak plasma concentration and area under the curve for bupropion and the three metabolites. Bupropion hydrochloride extended-release tablets (SR) can be taken with or without food. Bupropion Cmax and AUC were increased by 11% to 35% and 16% to 19%, respectively, when bupropion hydrochloride extended-release tablets (SR) was administered with food to healthy volunteers in three trials. The food effect is not considered clinically significant. Following a single-dose administration of bupropion hydrochloride extended-release tablets (SR) in humans, Cmax of bupropion's metabolite hydroxybupropion occurs approximately 6 hours post-dose and is approximately 10 times the peak level of the parent drug at steady state. The elimination half-life of hydroxybupropion is approximately 20 (±5) hours and its AUC at steady state is about 17 times that of bupropion. The times to peak concentrations for the erythrohydrobupropion and threohydrobupropion metabolites are similar to that of the hydroxybupropion metabolite. However, their elimination half-lives are longer, 33(±10) and 37 (±13) hours, respectively, and steady-state AUCs are 1.5 and 7 times that of bupropion, respectively. •Absorption (Drug B): Tmax is 0.75 h. Administration with a high-fat meal reduces Cmax by 35% and increases Tmax to 2.5 h. •Volume of distribution (Drug A): No volume of distribution available •Volume of distribution (Drug B): The apparent volume of disribution during the terminal phase is 155 L •Protein binding (Drug A): In vitro tests show that bupropion is 84% bound to human plasma proteins at concentrations up to 200 mcg per mL. The extent of protein binding of the hydroxybupropion metabolite is similar to that for bupropion, whereas the extent of protein binding of the threohydrobupropion metabolite is about half that seen with bupropion. •Protein binding (Drug B): Naldemedine is 93-94% bound to human plasma proteins. •Metabolism (Drug A): Bupropion is extensively metabolized in humans. Three metabolites are active: hydroxybupropion, which is formed via hydroxylation of the tert-butyl group of bupropion, and the amino-alcohol isomers, threohydrobupropion and erythrohydrobupropion, which are formed via reduction of the carbonyl group. In vitro findings suggest that CYP2B6 is the principal isoenzyme involved in the formation of hydroxybupropion, while cytochrome P450 enzymes are not involved in the formation of threohydrobupropion. Hydroxybupropion has been shown to have the same affinity as bupropion for the norepinephrine transporter (NET) but approximately 50% of its antidepressant activity despite reaching concentrations of ~10-fold higher than that of the parent drug. Oxidation of the bupropion side chain results in the formation of a glycine conjugate of meta-chlorobenzoic acid, which is then excreted as the major urinary metabolite. The potency and toxicity of the metabolites relative to bupropion have not been fully characterized. However, it has been demonstrated in an antidepressant screening test in mice that hydroxybupropion is one-half as potent as bupropion, while threohydrobupropion and erythrohydrobupropion are 5-fold less potent than bupropion. This may be of clinical importance because the plasma concentrations of the metabolites are as high as or higher than those of bupropion. Bupropion and its metabolites exhibit linear kinetics following chronic administration of 300 to 450 mg per day. •Metabolism (Drug B): Naldemedine is mainly metabolized to nor-naldemedine by CYP3A. Some metabolism to naldemedine-3-glucuronide occurs via UGT1A3. Both metabolites are acitive but less potent than naldemedine. The relative exposures of these metabolites are 9-13% and <3% for nor-naldemedine and naldemedine-3-glucuronide respectively. Naldemedine is also cleaved in the intestine to form benzamidine and naldemedine carboxylic acid. •Route of elimination (Drug A): Bupropion is extensively metabolized in humans. Oxidation of the bupropion side chain results in the formation of a glycine conjugate of metachlorobenzoic acid, which is then excreted as the major urinary metabolite. Following oral administration of 200 mg of 14C-bupropion in humans, 87% and 10% of the radioactive dose were recovered in the urine and feces, respectively. However, the fraction of the oral dose of bupropion excreted unchanged was only 0.5%, a finding consistent with the extensive metabolism of bupropion. •Route of elimination (Drug B): 57% of naldemedine is excreted in the urine with 16-18% as the parent compound and 35% is excreted in the feces. •Half-life (Drug A): 24 hours •Half-life (Drug B): The terminal elimination half life is 11 h. •Clearance (Drug A): No clearance available •Clearance (Drug B): No clearance available •Toxicity (Drug A): Symptoms of overdose include seizures, hallucinations, loss of consciousness, tachycardia, and cardiac arrest. •Toxicity (Drug B): The most common adverse effects of naldemedine are abdominal pain (11%), diarrhea (7%), nausea (6%), vomiting (3%), and gastroenteritis (3%). •Brand Names (Drug A): Aplenzin, Auvelity, Budeprion, Contrave, Forfivo, Wellbutrin, Zyban •Brand Names (Drug B): Symproic •Synonyms (Drug A): No synonyms listed •Synonyms (Drug B): No synonyms listed •Summary (Drug A): Bupropion is a norepinephrine and dopamine reuptake inhibitor used in the treatment of major depressive disorder (MDD), seasonal affective disorder (SAD), and as an aid to smoking cessation. •Summary (Drug B): Naldemedine is an opioid antagonist used to to treat opioid-induced constipation. Output: The renal excretion of drugs is the overall result of a combination of kidney processes that include glomerular filtration, passive diffusion, tubular secretion, and tubular reabsorption. Since two of these mechanisms - tubular secretion and reabsorption - are saturable processes , they are consequently susceptible to competition between multiple substrates excreted by the kidneys. If two or more medications that are mainly renally excreted are co-administered, they may compete for renal elimination; there is a large likelihood that one agent may "out-compete" or saturate the renal excretion mechanisms before the other concomitantly administered agent(s) are excreted. As a result, the elimination of these other concurrently administered agents may be inhibited or otherwise delayed, which could lead to increases in their serum concentrations and the risk, incidence, and/or severity of adverse effects associated with the exposure to such drugs. The severity of the interaction is minor.

Does Bupropion and Nalidixic acid interact?

•Drug A: Bupropion •Drug B: Nalidixic acid •Severity: MODERATE •Description: The risk or severity of seizure can be increased when Bupropion is combined with Nalidixic acid. •Extended Description: Bupropion carries a dose-dependent risk of seizure1 that may be further exacerbated when combined with other medications that can reduce the seizure threshold (i.e. increase the risk of seizure), such as the affected drug. This risk may be also compounded by patient-specific factors that may increase the risk of seizure such as metabolic disorders and illicit drug use. •Indication (Drug A): Bupropion is indicated for the treatment of major depressive disorder (MDD), seasonal affective disorder (SAD), and as an aid to smoking cessation. When used in combination with naltrexone as the marketed product ContraveⓇ, bupropion is indicated as an adjunct to a reduced-calorie diet and increased physical activity for chronic weight management in adults with an initial body mass index (BMI) of: 30 kg/m^2 or greater (obese) or 27 kg/m^2 or greater (overweight) in the presence of at least one weight-related comorbid condition (e.g., hypertension, type 2 diabetes mellitus, or dyslipidemia). Bupropion is also used off-label as a first-line treatment in patients with ADHD and comorbid bipolar disorder when used as an adjunct to mood stabilizers. •Indication (Drug B): For the treatment of urinary tract infections caused by susceptible gram-negative microorganisms, including the majority of E. Coli, Enterobacter species, Klebsiella species, and Proteus species. •Pharmacodynamics (Drug A): Bupropion is chemically unrelated to tricyclic, tetracyclic, selective serotonin re-uptake inhibitors, or other known antidepressant agents. Compared to classical tricyclic antidepressants, Bupropion is a relatively weak inhibitor of the neuronal uptake of norepinephrine and dopamine. In addition, Bupropion does not inhibit monoamine oxidase. Bupropion has been found to be essentially inactive at the serotonin transporter (SERT)(IC50 >10 000 nM), however both bupropion and its primary metabolite hydroxybupropion have been found to block the function of cation-selective serotonin type 3A receptors (5-HT3ARs). Bupropion produces dose-related central nervous system (CNS) stimulant effects in animals, as evidenced by increased locomotor activity, increased rates of responding in various schedule-controlled operant behaviour tasks, and, at high doses, induction of mild stereotyped behaviour. Due to these stimulant effects and selective activity at dopamine and norepinephrine receptors, bupropion has been identified as having an abuse potential. Bupropion has a similar structure to the controlled substance Cathinone, and has been identified as having mild amphetamine-like activity, particularly when inhaled or injected. Bupropion is also known to lower the seizure threshold, making any pre-existing seizure conditions a contraindication to its use. This risk is exacerbated when bupropion is combined with other drugs or substances that lower the seizure threshold, such as cocaine, or in clinical situations that would increase the risk of a seizure such as abrupt alcohol or benzodiazepine withdrawal. As norepinephrine has been shown to have anticonvulsant properties, bupropion's inhibitory effects on NET are thought to contribute to its pro-convulsant activity. Bupropion has been shown to increase blood pressure and pose a risk for exacerbation of unmanaged or pre-existing hypertension, however, clinical trials of bupropion in smokers with CVD have not identified an increased incidence of CV events including stroke or heart attack. In clinical trials, the mean increase in systolic blood pressure associated with the use of bupropion was found to be 1.3 mmHg. •Pharmacodynamics (Drug B): Nalidixic acid is a quinolone antibacterial agent for oral administration. Nalidixic acid has marked antibacterial activity against gram-negative bacteria including Enterobacter species, Escherichia coli, Morganella Morganii; Proteus Mirabilis, Proteus vulgaris, and Providencia rettgeri. Pseudomonas species are generally resistant to the drug. Nalidixic acid is bactericidal and is effective over the entire urinary pH range. Conventional chromosomal resistance to nalidixic acid taken in full dosage has been reported to emerge in approximately 2 to 14 percent of patients during treatment; however, bacterial resistance to nalidixic acid has not been shown to be transferable via R factor. •Mechanism of action (Drug A): Bupropion is a norepinephrine/dopamine-reuptake inhibitor (NDRI) that exerts its pharmacological effects by weakly inhibiting the enzymes involved in the uptake of the neurotransmitters norepinephrine and dopamine from the synaptic cleft, therefore prolonging their duration of action within the neuronal synapse and the downstream effects of these neurotransmitters. More specifically, bupropion binds to the norepinephrine transporter (NET) and the dopamine transporter (DAT). Bupropion was originally classified as an "atypical" antidepressant because it does not exert the same effects as the classical antidepressants such as Monoamine Oxidase Inhibitors (MAOIs), Tricyclic Antidepressants (TCAs), or Selective Serotonin Reuptake Inhibitors (SSRIs). While it has comparable effectiveness to typical first-line options for the treatment of depression such as SSRIs, bupropion is a unique option for the treatment of MDD as it lacks any clinically relevant serotonergic effects, typical of other mood medications, or any effects on histamine or adrenaline receptors. Lack of activity at these receptors results in a more tolerable side effect profile; bupropion is less likely to cause sexual side effects, sedation, or weight gain as compared to SSRIs or TCAs, for example. When used as an aid to smoking cessation, bupropion is thought to confer its anti-craving and anti-withdrawal effects by inhibiting dopamine reuptake, which is thought to be involved in the reward pathways associated with nicotine, and through the antagonism of the nicotinic acetylcholinergic receptor (AChR), thereby blunting the effects of nicotine. Furthermore, the stimulatory effects produced by bupropion in the central nervous system are similar to nicotine's effects, making low doses of bupropion a suitable option as a nicotine substitute. When used in combination with naltrexone in the marketed product ContraveⓇ for chronic weight management, the two components are thought to have effects on areas of the brain involved in the regulation of food intake. This includes the hypothalamus, which is involved in appetite regulation, and the mesolimbic dopamine circuit, which is involved in reward pathways. Studies have shown that the combined activity of bupropion and naltrexone increase the firing rate of hypothalamic pro-opiomelanocortin (POMC) neurons and blockade of opioid receptor-mediated POMC auto-inhibition, which are associated with a reduction in food intake and increased energy expenditure. This combination was also found to reduce food intake when injected directly into the ventral tegmental area of the mesolimbic circuit in mice, which is an area associated with the regulation of reward pathways. •Mechanism of action (Drug B): Evidence exists for Nalidixic acid that its active metabolite, hydroxynalidixic acid, binds strongly, but reversibly, to DNA, interfering with synthesis of RNA and, consequently, with protein synthesis. •Absorption (Drug A): Bupropion is currently available in 3 distinct, but bioequivalent formulations: immediate release (IR), sustained-release (SR), and extended-release (XL). Immediate Release Formulation In humans, following oral administration of bupropion hydrochloride tablets, peak plasma bupropion concentrations are usually achieved within 2 hours. IR formulations provide a short duration of action and are therefore generally dosed three times per day. Sustained Release Formulation In humans, following oral administration of bupropion hydrochloride sustained-release tablets (SR), peak plasma concentration (Cmax) of bupropion is usually achieved within 3 hours. SR formulations provide a 12-hour extended release of medication and are therefore generally dosed twice per day. Extended Release Formulation Following single oral administration of bupropion hydrochloride extended-release tablets (XL) to healthy volunteers, the median time to peak plasma concentrations for bupropion was approximately 5 hours. The presence of food did not affect the peak concentration or area under the curve of bupropion. XL formulations provide a 24-hour extended release of medication and are therefore generally dosed once per day/ In a trial comparing chronic dosing with bupropion hydrochloride extended-release tablets (SR) 150 mg twice daily to bupropion immediate-release formulation 100 mg 3 times daily, the steady state Cmax for bupropion after bupropion hydrochloride sustained-release tablets (SR) administration was approximately 85% of those achieved after bupropion immediate-release formulation administration. Exposure (AUC) to bupropion was equivalent for both formulations. Bioequivalence was also demonstrated for all three major active metabolites (i.e., hydroxybupropion, threohydrobupropion and erythrohydrobupropion) for both Cmax and AUC. Thus, at steady state, bupropion hydrochloride sustained-release tablets (SR) given twice daily, and the immediate-release formulation of bupropion given 3 times daily, are essentially bioequivalent for both bupropion and the 3 quantitatively important metabolites. Furthermore, in a study comparing 14-day dosing with bupropion hydrochloride extended-release tablets (XL), 300 mg once-daily to the immediate-release formulation of bupropion at 100 mg 3 times daily, equivalence was demonstrated for peak plasma concentration and area under the curve for bupropion and the three metabolites (hydroxybupropion, threohydrobupropion, and erythrohydrobupropion). Additionally, in a study comparing 14-day dosing with bupropion hydrochloride extended-release tablets (XL) 300 mg once daily to the sustained-release formulation of bupropion at 150 mg 2 times daily, equivalence was demonstrated for peak plasma concentration and area under the curve for bupropion and the three metabolites. Bupropion hydrochloride extended-release tablets (SR) can be taken with or without food. Bupropion Cmax and AUC were increased by 11% to 35% and 16% to 19%, respectively, when bupropion hydrochloride extended-release tablets (SR) was administered with food to healthy volunteers in three trials. The food effect is not considered clinically significant. Following a single-dose administration of bupropion hydrochloride extended-release tablets (SR) in humans, Cmax of bupropion's metabolite hydroxybupropion occurs approximately 6 hours post-dose and is approximately 10 times the peak level of the parent drug at steady state. The elimination half-life of hydroxybupropion is approximately 20 (±5) hours and its AUC at steady state is about 17 times that of bupropion. The times to peak concentrations for the erythrohydrobupropion and threohydrobupropion metabolites are similar to that of the hydroxybupropion metabolite. However, their elimination half-lives are longer, 33(±10) and 37 (±13) hours, respectively, and steady-state AUCs are 1.5 and 7 times that of bupropion, respectively. •Absorption (Drug B): Following oral administration, nalidixic acid is rapidly absorbed from the gastrointestinal tract. Bioavailability is approximately 96%. Absorption may be delayed if taken with antacids. •Volume of distribution (Drug A): No volume of distribution available •Volume of distribution (Drug B): No volume of distribution available •Protein binding (Drug A): In vitro tests show that bupropion is 84% bound to human plasma proteins at concentrations up to 200 mcg per mL. The extent of protein binding of the hydroxybupropion metabolite is similar to that for bupropion, whereas the extent of protein binding of the threohydrobupropion metabolite is about half that seen with bupropion. •Protein binding (Drug B): Nalidixic acid is 93% bound to protein in the blood, and the active metabolite, hydroxynalidixic acid is 63% bound. •Metabolism (Drug A): Bupropion is extensively metabolized in humans. Three metabolites are active: hydroxybupropion, which is formed via hydroxylation of the tert-butyl group of bupropion, and the amino-alcohol isomers, threohydrobupropion and erythrohydrobupropion, which are formed via reduction of the carbonyl group. In vitro findings suggest that CYP2B6 is the principal isoenzyme involved in the formation of hydroxybupropion, while cytochrome P450 enzymes are not involved in the formation of threohydrobupropion. Hydroxybupropion has been shown to have the same affinity as bupropion for the norepinephrine transporter (NET) but approximately 50% of its antidepressant activity despite reaching concentrations of ~10-fold higher than that of the parent drug. Oxidation of the bupropion side chain results in the formation of a glycine conjugate of meta-chlorobenzoic acid, which is then excreted as the major urinary metabolite. The potency and toxicity of the metabolites relative to bupropion have not been fully characterized. However, it has been demonstrated in an antidepressant screening test in mice that hydroxybupropion is one-half as potent as bupropion, while threohydrobupropion and erythrohydrobupropion are 5-fold less potent than bupropion. This may be of clinical importance because the plasma concentrations of the metabolites are as high as or higher than those of bupropion. Bupropion and its metabolites exhibit linear kinetics following chronic administration of 300 to 450 mg per day. •Metabolism (Drug B): Hepatic. 30% of administered dose is metabolized to the active metabolite, hydroxynalidixic acid. Rapid conjugation of parent drug and active metabolite to inactive metabolites. Metabolism may vary widely among individuals. In the urine, hydroxynalidixic acid represents 80 to 85% of the antibacterial activity. •Route of elimination (Drug A): Bupropion is extensively metabolized in humans. Oxidation of the bupropion side chain results in the formation of a glycine conjugate of metachlorobenzoic acid, which is then excreted as the major urinary metabolite. Following oral administration of 200 mg of 14C-bupropion in humans, 87% and 10% of the radioactive dose were recovered in the urine and feces, respectively. However, the fraction of the oral dose of bupropion excreted unchanged was only 0.5%, a finding consistent with the extensive metabolism of bupropion. •Route of elimination (Drug B): Following oral administration, NegGram is rapidly absorbed from the gastrointestinal tract, partially metabolized in the liver, and rapidly excreted through the kidneys. Approximately four percent of NegGram is excreted in the feces. •Half-life (Drug A): 24 hours •Half-life (Drug B): 1.1 to 2.5 hours in healthy adult patients, and up to 21 hours in patients with impaired renal function. •Clearance (Drug A): No clearance available •Clearance (Drug B): No clearance available •Toxicity (Drug A): Symptoms of overdose include seizures, hallucinations, loss of consciousness, tachycardia, and cardiac arrest. •Toxicity (Drug B): ORAL (LD 50 ): Acute: 1160 mg/kg [Rat]. 572 mg/kg [Mouse]. Toxic psychosis, convulsions, increased intracranial pressure, or metabolic acidosis may occur in patients taking more than the recommended dosage. Vomiting, nausea, and lethargy may also occur following overdosage. •Brand Names (Drug A): Aplenzin, Auvelity, Budeprion, Contrave, Forfivo, Wellbutrin, Zyban •Brand Names (Drug B): No brand names available •Synonyms (Drug A): No synonyms listed •Synonyms (Drug B): Acide nalidixique Acido nalidixico Acidum nalidixicum Nalidixic acid Nalidixinsäure •Summary (Drug A): Bupropion is a norepinephrine and dopamine reuptake inhibitor used in the treatment of major depressive disorder (MDD), seasonal affective disorder (SAD), and as an aid to smoking cessation. •Summary (Drug B): Nalidixic acid is a quinolone antibiotic used to treat urinary tract infections.

Bupropion carries a dose-dependent risk of seizure1 that may be further exacerbated when combined with other medications that can reduce the seizure threshold (i.e. increase the risk of seizure), such as the affected drug. This risk may be also compounded by patient-specific factors that may increase the risk of seizure such as metabolic disorders and illicit drug use. The severity of the interaction is moderate.

Question: Does Bupropion and Nalidixic acid interact? Information: •Drug A: Bupropion •Drug B: Nalidixic acid •Severity: MODERATE •Description: The risk or severity of seizure can be increased when Bupropion is combined with Nalidixic acid. •Extended Description: Bupropion carries a dose-dependent risk of seizure1 that may be further exacerbated when combined with other medications that can reduce the seizure threshold (i.e. increase the risk of seizure), such as the affected drug. This risk may be also compounded by patient-specific factors that may increase the risk of seizure such as metabolic disorders and illicit drug use. •Indication (Drug A): Bupropion is indicated for the treatment of major depressive disorder (MDD), seasonal affective disorder (SAD), and as an aid to smoking cessation. When used in combination with naltrexone as the marketed product ContraveⓇ, bupropion is indicated as an adjunct to a reduced-calorie diet and increased physical activity for chronic weight management in adults with an initial body mass index (BMI) of: 30 kg/m^2 or greater (obese) or 27 kg/m^2 or greater (overweight) in the presence of at least one weight-related comorbid condition (e.g., hypertension, type 2 diabetes mellitus, or dyslipidemia). Bupropion is also used off-label as a first-line treatment in patients with ADHD and comorbid bipolar disorder when used as an adjunct to mood stabilizers. •Indication (Drug B): For the treatment of urinary tract infections caused by susceptible gram-negative microorganisms, including the majority of E. Coli, Enterobacter species, Klebsiella species, and Proteus species. •Pharmacodynamics (Drug A): Bupropion is chemically unrelated to tricyclic, tetracyclic, selective serotonin re-uptake inhibitors, or other known antidepressant agents. Compared to classical tricyclic antidepressants, Bupropion is a relatively weak inhibitor of the neuronal uptake of norepinephrine and dopamine. In addition, Bupropion does not inhibit monoamine oxidase. Bupropion has been found to be essentially inactive at the serotonin transporter (SERT)(IC50 >10 000 nM), however both bupropion and its primary metabolite hydroxybupropion have been found to block the function of cation-selective serotonin type 3A receptors (5-HT3ARs). Bupropion produces dose-related central nervous system (CNS) stimulant effects in animals, as evidenced by increased locomotor activity, increased rates of responding in various schedule-controlled operant behaviour tasks, and, at high doses, induction of mild stereotyped behaviour. Due to these stimulant effects and selective activity at dopamine and norepinephrine receptors, bupropion has been identified as having an abuse potential. Bupropion has a similar structure to the controlled substance Cathinone, and has been identified as having mild amphetamine-like activity, particularly when inhaled or injected. Bupropion is also known to lower the seizure threshold, making any pre-existing seizure conditions a contraindication to its use. This risk is exacerbated when bupropion is combined with other drugs or substances that lower the seizure threshold, such as cocaine, or in clinical situations that would increase the risk of a seizure such as abrupt alcohol or benzodiazepine withdrawal. As norepinephrine has been shown to have anticonvulsant properties, bupropion's inhibitory effects on NET are thought to contribute to its pro-convulsant activity. Bupropion has been shown to increase blood pressure and pose a risk for exacerbation of unmanaged or pre-existing hypertension, however, clinical trials of bupropion in smokers with CVD have not identified an increased incidence of CV events including stroke or heart attack. In clinical trials, the mean increase in systolic blood pressure associated with the use of bupropion was found to be 1.3 mmHg. •Pharmacodynamics (Drug B): Nalidixic acid is a quinolone antibacterial agent for oral administration. Nalidixic acid has marked antibacterial activity against gram-negative bacteria including Enterobacter species, Escherichia coli, Morganella Morganii; Proteus Mirabilis, Proteus vulgaris, and Providencia rettgeri. Pseudomonas species are generally resistant to the drug. Nalidixic acid is bactericidal and is effective over the entire urinary pH range. Conventional chromosomal resistance to nalidixic acid taken in full dosage has been reported to emerge in approximately 2 to 14 percent of patients during treatment; however, bacterial resistance to nalidixic acid has not been shown to be transferable via R factor. •Mechanism of action (Drug A): Bupropion is a norepinephrine/dopamine-reuptake inhibitor (NDRI) that exerts its pharmacological effects by weakly inhibiting the enzymes involved in the uptake of the neurotransmitters norepinephrine and dopamine from the synaptic cleft, therefore prolonging their duration of action within the neuronal synapse and the downstream effects of these neurotransmitters. More specifically, bupropion binds to the norepinephrine transporter (NET) and the dopamine transporter (DAT). Bupropion was originally classified as an "atypical" antidepressant because it does not exert the same effects as the classical antidepressants such as Monoamine Oxidase Inhibitors (MAOIs), Tricyclic Antidepressants (TCAs), or Selective Serotonin Reuptake Inhibitors (SSRIs). While it has comparable effectiveness to typical first-line options for the treatment of depression such as SSRIs, bupropion is a unique option for the treatment of MDD as it lacks any clinically relevant serotonergic effects, typical of other mood medications, or any effects on histamine or adrenaline receptors. Lack of activity at these receptors results in a more tolerable side effect profile; bupropion is less likely to cause sexual side effects, sedation, or weight gain as compared to SSRIs or TCAs, for example. When used as an aid to smoking cessation, bupropion is thought to confer its anti-craving and anti-withdrawal effects by inhibiting dopamine reuptake, which is thought to be involved in the reward pathways associated with nicotine, and through the antagonism of the nicotinic acetylcholinergic receptor (AChR), thereby blunting the effects of nicotine. Furthermore, the stimulatory effects produced by bupropion in the central nervous system are similar to nicotine's effects, making low doses of bupropion a suitable option as a nicotine substitute. When used in combination with naltrexone in the marketed product ContraveⓇ for chronic weight management, the two components are thought to have effects on areas of the brain involved in the regulation of food intake. This includes the hypothalamus, which is involved in appetite regulation, and the mesolimbic dopamine circuit, which is involved in reward pathways. Studies have shown that the combined activity of bupropion and naltrexone increase the firing rate of hypothalamic pro-opiomelanocortin (POMC) neurons and blockade of opioid receptor-mediated POMC auto-inhibition, which are associated with a reduction in food intake and increased energy expenditure. This combination was also found to reduce food intake when injected directly into the ventral tegmental area of the mesolimbic circuit in mice, which is an area associated with the regulation of reward pathways. •Mechanism of action (Drug B): Evidence exists for Nalidixic acid that its active metabolite, hydroxynalidixic acid, binds strongly, but reversibly, to DNA, interfering with synthesis of RNA and, consequently, with protein synthesis. •Absorption (Drug A): Bupropion is currently available in 3 distinct, but bioequivalent formulations: immediate release (IR), sustained-release (SR), and extended-release (XL). Immediate Release Formulation In humans, following oral administration of bupropion hydrochloride tablets, peak plasma bupropion concentrations are usually achieved within 2 hours. IR formulations provide a short duration of action and are therefore generally dosed three times per day. Sustained Release Formulation In humans, following oral administration of bupropion hydrochloride sustained-release tablets (SR), peak plasma concentration (Cmax) of bupropion is usually achieved within 3 hours. SR formulations provide a 12-hour extended release of medication and are therefore generally dosed twice per day. Extended Release Formulation Following single oral administration of bupropion hydrochloride extended-release tablets (XL) to healthy volunteers, the median time to peak plasma concentrations for bupropion was approximately 5 hours. The presence of food did not affect the peak concentration or area under the curve of bupropion. XL formulations provide a 24-hour extended release of medication and are therefore generally dosed once per day/ In a trial comparing chronic dosing with bupropion hydrochloride extended-release tablets (SR) 150 mg twice daily to bupropion immediate-release formulation 100 mg 3 times daily, the steady state Cmax for bupropion after bupropion hydrochloride sustained-release tablets (SR) administration was approximately 85% of those achieved after bupropion immediate-release formulation administration. Exposure (AUC) to bupropion was equivalent for both formulations. Bioequivalence was also demonstrated for all three major active metabolites (i.e., hydroxybupropion, threohydrobupropion and erythrohydrobupropion) for both Cmax and AUC. Thus, at steady state, bupropion hydrochloride sustained-release tablets (SR) given twice daily, and the immediate-release formulation of bupropion given 3 times daily, are essentially bioequivalent for both bupropion and the 3 quantitatively important metabolites. Furthermore, in a study comparing 14-day dosing with bupropion hydrochloride extended-release tablets (XL), 300 mg once-daily to the immediate-release formulation of bupropion at 100 mg 3 times daily, equivalence was demonstrated for peak plasma concentration and area under the curve for bupropion and the three metabolites (hydroxybupropion, threohydrobupropion, and erythrohydrobupropion). Additionally, in a study comparing 14-day dosing with bupropion hydrochloride extended-release tablets (XL) 300 mg once daily to the sustained-release formulation of bupropion at 150 mg 2 times daily, equivalence was demonstrated for peak plasma concentration and area under the curve for bupropion and the three metabolites. Bupropion hydrochloride extended-release tablets (SR) can be taken with or without food. Bupropion Cmax and AUC were increased by 11% to 35% and 16% to 19%, respectively, when bupropion hydrochloride extended-release tablets (SR) was administered with food to healthy volunteers in three trials. The food effect is not considered clinically significant. Following a single-dose administration of bupropion hydrochloride extended-release tablets (SR) in humans, Cmax of bupropion's metabolite hydroxybupropion occurs approximately 6 hours post-dose and is approximately 10 times the peak level of the parent drug at steady state. The elimination half-life of hydroxybupropion is approximately 20 (±5) hours and its AUC at steady state is about 17 times that of bupropion. The times to peak concentrations for the erythrohydrobupropion and threohydrobupropion metabolites are similar to that of the hydroxybupropion metabolite. However, their elimination half-lives are longer, 33(±10) and 37 (±13) hours, respectively, and steady-state AUCs are 1.5 and 7 times that of bupropion, respectively. •Absorption (Drug B): Following oral administration, nalidixic acid is rapidly absorbed from the gastrointestinal tract. Bioavailability is approximately 96%. Absorption may be delayed if taken with antacids. •Volume of distribution (Drug A): No volume of distribution available •Volume of distribution (Drug B): No volume of distribution available •Protein binding (Drug A): In vitro tests show that bupropion is 84% bound to human plasma proteins at concentrations up to 200 mcg per mL. The extent of protein binding of the hydroxybupropion metabolite is similar to that for bupropion, whereas the extent of protein binding of the threohydrobupropion metabolite is about half that seen with bupropion. •Protein binding (Drug B): Nalidixic acid is 93% bound to protein in the blood, and the active metabolite, hydroxynalidixic acid is 63% bound. •Metabolism (Drug A): Bupropion is extensively metabolized in humans. Three metabolites are active: hydroxybupropion, which is formed via hydroxylation of the tert-butyl group of bupropion, and the amino-alcohol isomers, threohydrobupropion and erythrohydrobupropion, which are formed via reduction of the carbonyl group. In vitro findings suggest that CYP2B6 is the principal isoenzyme involved in the formation of hydroxybupropion, while cytochrome P450 enzymes are not involved in the formation of threohydrobupropion. Hydroxybupropion has been shown to have the same affinity as bupropion for the norepinephrine transporter (NET) but approximately 50% of its antidepressant activity despite reaching concentrations of ~10-fold higher than that of the parent drug. Oxidation of the bupropion side chain results in the formation of a glycine conjugate of meta-chlorobenzoic acid, which is then excreted as the major urinary metabolite. The potency and toxicity of the metabolites relative to bupropion have not been fully characterized. However, it has been demonstrated in an antidepressant screening test in mice that hydroxybupropion is one-half as potent as bupropion, while threohydrobupropion and erythrohydrobupropion are 5-fold less potent than bupropion. This may be of clinical importance because the plasma concentrations of the metabolites are as high as or higher than those of bupropion. Bupropion and its metabolites exhibit linear kinetics following chronic administration of 300 to 450 mg per day. •Metabolism (Drug B): Hepatic. 30% of administered dose is metabolized to the active metabolite, hydroxynalidixic acid. Rapid conjugation of parent drug and active metabolite to inactive metabolites. Metabolism may vary widely among individuals. In the urine, hydroxynalidixic acid represents 80 to 85% of the antibacterial activity. •Route of elimination (Drug A): Bupropion is extensively metabolized in humans. Oxidation of the bupropion side chain results in the formation of a glycine conjugate of metachlorobenzoic acid, which is then excreted as the major urinary metabolite. Following oral administration of 200 mg of 14C-bupropion in humans, 87% and 10% of the radioactive dose were recovered in the urine and feces, respectively. However, the fraction of the oral dose of bupropion excreted unchanged was only 0.5%, a finding consistent with the extensive metabolism of bupropion. •Route of elimination (Drug B): Following oral administration, NegGram is rapidly absorbed from the gastrointestinal tract, partially metabolized in the liver, and rapidly excreted through the kidneys. Approximately four percent of NegGram is excreted in the feces. •Half-life (Drug A): 24 hours •Half-life (Drug B): 1.1 to 2.5 hours in healthy adult patients, and up to 21 hours in patients with impaired renal function. •Clearance (Drug A): No clearance available •Clearance (Drug B): No clearance available •Toxicity (Drug A): Symptoms of overdose include seizures, hallucinations, loss of consciousness, tachycardia, and cardiac arrest. •Toxicity (Drug B): ORAL (LD 50 ): Acute: 1160 mg/kg [Rat]. 572 mg/kg [Mouse]. Toxic psychosis, convulsions, increased intracranial pressure, or metabolic acidosis may occur in patients taking more than the recommended dosage. Vomiting, nausea, and lethargy may also occur following overdosage. •Brand Names (Drug A): Aplenzin, Auvelity, Budeprion, Contrave, Forfivo, Wellbutrin, Zyban •Brand Names (Drug B): No brand names available •Synonyms (Drug A): No synonyms listed •Synonyms (Drug B): Acide nalidixique Acido nalidixico Acidum nalidixicum Nalidixic acid Nalidixinsäure •Summary (Drug A): Bupropion is a norepinephrine and dopamine reuptake inhibitor used in the treatment of major depressive disorder (MDD), seasonal affective disorder (SAD), and as an aid to smoking cessation. •Summary (Drug B): Nalidixic acid is a quinolone antibiotic used to treat urinary tract infections. Output: Bupropion carries a dose-dependent risk of seizure1 that may be further exacerbated when combined with other medications that can reduce the seizure threshold (i.e. increase the risk of seizure), such as the affected drug. This risk may be also compounded by patient-specific factors that may increase the risk of seizure such as metabolic disorders and illicit drug use. The severity of the interaction is moderate.

Does Bupropion and Nalmefene interact?

•Drug A: Bupropion •Drug B: Nalmefene •Severity: MINOR •Description: Bupropion may decrease the excretion rate of Nalmefene which could result in a higher serum level. •Extended Description: The renal excretion of drugs is the overall result of a combination of kidney processes that include glomerular filtration, passive diffusion, tubular secretion, and tubular reabsorption. Since two of these mechanisms - tubular secretion and reabsorption - are saturable processes , they are consequently susceptible to competition between multiple substrates excreted by the kidneys. If two or more medications that are mainly renally excreted are co-administered, they may compete for renal elimination; there is a large likelihood that one agent may "out-compete" or saturate the renal excretion mechanisms before the other concomitantly administered agent(s) are excreted. As a result, the elimination of these other concurrently administered agents may be inhibited or otherwise delayed, which could lead to increases in their serum concentrations and the risk, incidence, and/or severity of adverse effects associated with the exposure to such drugs. •Indication (Drug A): Bupropion is indicated for the treatment of major depressive disorder (MDD), seasonal affective disorder (SAD), and as an aid to smoking cessation. When used in combination with naltrexone as the marketed product ContraveⓇ, bupropion is indicated as an adjunct to a reduced-calorie diet and increased physical activity for chronic weight management in adults with an initial body mass index (BMI) of: 30 kg/m^2 or greater (obese) or 27 kg/m^2 or greater (overweight) in the presence of at least one weight-related comorbid condition (e.g., hypertension, type 2 diabetes mellitus, or dyslipidemia). Bupropion is also used off-label as a first-line treatment in patients with ADHD and comorbid bipolar disorder when used as an adjunct to mood stabilizers. •Indication (Drug B): Nalmefene oral tablet is indicated for the reduction of alcohol consumption in adult patients with alcohol dependence who have a high drinking risk level (DRL), without physical withdrawal symptoms and who do not require immediate detoxification. Nalmefene should only be prescribed in conjunction with continuous psychosocial support focused on treatment adherence and reducing alcohol consumption. Nalmefene should be initiated only in patients who continue to have a high DRL two weeks after the initial assessment. Nalmefene injection and nasal spray are indicated for the complete or partial reversal of opioid drug effects, including respiratory depression, induced by either natural or synthetic opioids. They are also indicated in the management of known or suspected opioid overdose. Nalmefene injection can be used for postoperative opioid overdose reversal. •Pharmacodynamics (Drug A): Bupropion is chemically unrelated to tricyclic, tetracyclic, selective serotonin re-uptake inhibitors, or other known antidepressant agents. Compared to classical tricyclic antidepressants, Bupropion is a relatively weak inhibitor of the neuronal uptake of norepinephrine and dopamine. In addition, Bupropion does not inhibit monoamine oxidase. Bupropion has been found to be essentially inactive at the serotonin transporter (SERT)(IC50 >10 000 nM), however both bupropion and its primary metabolite hydroxybupropion have been found to block the function of cation-selective serotonin type 3A receptors (5-HT3ARs). Bupropion produces dose-related central nervous system (CNS) stimulant effects in animals, as evidenced by increased locomotor activity, increased rates of responding in various schedule-controlled operant behaviour tasks, and, at high doses, induction of mild stereotyped behaviour. Due to these stimulant effects and selective activity at dopamine and norepinephrine receptors, bupropion has been identified as having an abuse potential. Bupropion has a similar structure to the controlled substance Cathinone, and has been identified as having mild amphetamine-like activity, particularly when inhaled or injected. Bupropion is also known to lower the seizure threshold, making any pre-existing seizure conditions a contraindication to its use. This risk is exacerbated when bupropion is combined with other drugs or substances that lower the seizure threshold, such as cocaine, or in clinical situations that would increase the risk of a seizure such as abrupt alcohol or benzodiazepine withdrawal. As norepinephrine has been shown to have anticonvulsant properties, bupropion's inhibitory effects on NET are thought to contribute to its pro-convulsant activity. Bupropion has been shown to increase blood pressure and pose a risk for exacerbation of unmanaged or pre-existing hypertension, however, clinical trials of bupropion in smokers with CVD have not identified an increased incidence of CV events including stroke or heart attack. In clinical trials, the mean increase in systolic blood pressure associated with the use of bupropion was found to be 1.3 mmHg. •Pharmacodynamics (Drug B): Nalmefene is an opioid antagonist with no agonist activity. It works to prevent or reverse the effects of opioids, including respiratory depression, sedation, and hypotension. Nalmefene has a longer duration of action than naloxone, another opioid antagonist used to reverse opioid overdose. In a study of brain receptor occupancy, a 1 mg dose of nalmefene blocked over 80% of brain opioid receptors within five minutes after administration. Nalmefene has no opioid agonist activity and it is not associated with drug tolerance, physical dependence, or abuse potential. Nalmefene is not known to produce respiratory depression, psychotomimetic effects, or pupillary constriction. No pharmacological activity was observed when nalmefene was administered in the absence of opioid agonists. However, as with all opioid antagonists, nalmefene can produce acute withdrawal symptoms in individuals with opioid dependence. These withdrawal symptoms should be managed with symptomatic and supportive treatment: the administration of large amounts of opioids to patients receiving opioid antagonists in an attempt to overcome a full blockade has resulted in adverse respiratory and circulatory reactions. •Mechanism of action (Drug A): Bupropion is a norepinephrine/dopamine-reuptake inhibitor (NDRI) that exerts its pharmacological effects by weakly inhibiting the enzymes involved in the uptake of the neurotransmitters norepinephrine and dopamine from the synaptic cleft, therefore prolonging their duration of action within the neuronal synapse and the downstream effects of these neurotransmitters. More specifically, bupropion binds to the norepinephrine transporter (NET) and the dopamine transporter (DAT). Bupropion was originally classified as an "atypical" antidepressant because it does not exert the same effects as the classical antidepressants such as Monoamine Oxidase Inhibitors (MAOIs), Tricyclic Antidepressants (TCAs), or Selective Serotonin Reuptake Inhibitors (SSRIs). While it has comparable effectiveness to typical first-line options for the treatment of depression such as SSRIs, bupropion is a unique option for the treatment of MDD as it lacks any clinically relevant serotonergic effects, typical of other mood medications, or any effects on histamine or adrenaline receptors. Lack of activity at these receptors results in a more tolerable side effect profile; bupropion is less likely to cause sexual side effects, sedation, or weight gain as compared to SSRIs or TCAs, for example. When used as an aid to smoking cessation, bupropion is thought to confer its anti-craving and anti-withdrawal effects by inhibiting dopamine reuptake, which is thought to be involved in the reward pathways associated with nicotine, and through the antagonism of the nicotinic acetylcholinergic receptor (AChR), thereby blunting the effects of nicotine. Furthermore, the stimulatory effects produced by bupropion in the central nervous system are similar to nicotine's effects, making low doses of bupropion a suitable option as a nicotine substitute. When used in combination with naltrexone in the marketed product ContraveⓇ for chronic weight management, the two components are thought to have effects on areas of the brain involved in the regulation of food intake. This includes the hypothalamus, which is involved in appetite regulation, and the mesolimbic dopamine circuit, which is involved in reward pathways. Studies have shown that the combined activity of bupropion and naltrexone increase the firing rate of hypothalamic pro-opiomelanocortin (POMC) neurons and blockade of opioid receptor-mediated POMC auto-inhibition, which are associated with a reduction in food intake and increased energy expenditure. This combination was also found to reduce food intake when injected directly into the ventral tegmental area of the mesolimbic circuit in mice, which is an area associated with the regulation of reward pathways. •Mechanism of action (Drug B): The opioid system consists of three opioid receptors - mu (μ), delta (δ), and kappa (κ) - that are G-protein coupled receptors. Opioid receptors are activated by endogenous opioid peptides and are expressed throughout the brain to play a critical role in mood regulation, pain, reward, addictive behaviours, and substance use disorders. Opioid receptors are involved in various brain signalling pathways, including the mesolimbic pathway, sometimes referred to as the reward pathway. The mesolimbic pathway plays an important role in the positive reinforcement of natural rewards like food and drugs of abuse like exogenous opioid drugs. Many abused drugs activate mu-opioid receptors, leading to positive reinforcing effects. Alcohol consumption can also cause the release of endogenous opioids, which bind to mu and delta receptors, thereby increasing the release of dopamine in the nucleus accumbens to induce reward and positive reinforcement effects. Nalmefene is an antagonist at the mu and delta-opioid receptors and a partial agonist at the kappa-opioid receptor. As an antagonist, nalmefene blocks ligands from binding to the opioid receptor. Animal studies suggest that kappa-opioid receptor signalling blocks acute reward and positive reinforcement effects of drugs with abusive potential by decreasing dopamine in the nucleus accumbens. In vivo studies have demonstrated that nalmefene reduces alcohol consumption, possibly by modulating cortico-mesolimbic functions. Preclinical studies suggest that nalmefene restores alcohol-induced dysregulations of the MOR/endorphins and the KOR/dynorphin system. •Absorption (Drug A): Bupropion is currently available in 3 distinct, but bioequivalent formulations: immediate release (IR), sustained-release (SR), and extended-release (XL). Immediate Release Formulation In humans, following oral administration of bupropion hydrochloride tablets, peak plasma bupropion concentrations are usually achieved within 2 hours. IR formulations provide a short duration of action and are therefore generally dosed three times per day. Sustained Release Formulation In humans, following oral administration of bupropion hydrochloride sustained-release tablets (SR), peak plasma concentration (Cmax) of bupropion is usually achieved within 3 hours. SR formulations provide a 12-hour extended release of medication and are therefore generally dosed twice per day. Extended Release Formulation Following single oral administration of bupropion hydrochloride extended-release tablets (XL) to healthy volunteers, the median time to peak plasma concentrations for bupropion was approximately 5 hours. The presence of food did not affect the peak concentration or area under the curve of bupropion. XL formulations provide a 24-hour extended release of medication and are therefore generally dosed once per day/ In a trial comparing chronic dosing with bupropion hydrochloride extended-release tablets (SR) 150 mg twice daily to bupropion immediate-release formulation 100 mg 3 times daily, the steady state Cmax for bupropion after bupropion hydrochloride sustained-release tablets (SR) administration was approximately 85% of those achieved after bupropion immediate-release formulation administration. Exposure (AUC) to bupropion was equivalent for both formulations. Bioequivalence was also demonstrated for all three major active metabolites (i.e., hydroxybupropion, threohydrobupropion and erythrohydrobupropion) for both Cmax and AUC. Thus, at steady state, bupropion hydrochloride sustained-release tablets (SR) given twice daily, and the immediate-release formulation of bupropion given 3 times daily, are essentially bioequivalent for both bupropion and the 3 quantitatively important metabolites. Furthermore, in a study comparing 14-day dosing with bupropion hydrochloride extended-release tablets (XL), 300 mg once-daily to the immediate-release formulation of bupropion at 100 mg 3 times daily, equivalence was demonstrated for peak plasma concentration and area under the curve for bupropion and the three metabolites (hydroxybupropion, threohydrobupropion, and erythrohydrobupropion). Additionally, in a study comparing 14-day dosing with bupropion hydrochloride extended-release tablets (XL) 300 mg once daily to the sustained-release formulation of bupropion at 150 mg 2 times daily, equivalence was demonstrated for peak plasma concentration and area under the curve for bupropion and the three metabolites. Bupropion hydrochloride extended-release tablets (SR) can be taken with or without food. Bupropion Cmax and AUC were increased by 11% to 35% and 16% to 19%, respectively, when bupropion hydrochloride extended-release tablets (SR) was administered with food to healthy volunteers in three trials. The food effect is not considered clinically significant. Following a single-dose administration of bupropion hydrochloride extended-release tablets (SR) in humans, Cmax of bupropion's metabolite hydroxybupropion occurs approximately 6 hours post-dose and is approximately 10 times the peak level of the parent drug at steady state. The elimination half-life of hydroxybupropion is approximately 20 (±5) hours and its AUC at steady state is about 17 times that of bupropion. The times to peak concentrations for the erythrohydrobupropion and threohydrobupropion metabolites are similar to that of the hydroxybupropion metabolite. However, their elimination half-lives are longer, 33(±10) and 37 (±13) hours, respectively, and steady-state AUCs are 1.5 and 7 times that of bupropion, respectively. •Absorption (Drug B): Nalmefene is rapidly absorbed after a single oral administration of 18.06 mg with an absolute oral bioavailability of 41%. The C max was 16.5 ng/mL and T max was approximately 1.5 hours. The exposure (AUC) was 131 ng x h/mL. High-fat meal increased the AUC by 30% and C max by 50% and delayed T max by 30 min; however, this is unlikely of clinical significance. Nalmefene exhibits dose-proportional pharmacokinetics following intravenous administration of 0.5 mg to 2 mg. T max was 2.3 ± 1.1 hours following intramuscular administration and 1.5 ± 1.2 hours following subcutaneous administration. Therapeutic plasma concentrations are likely to be reached within 5 to 15 minutes after a 1 mg dose in an emergency. There is variability in the speed of absorption for intramuscular and subcutaneous dosing. •Volume of distribution (Drug A): No volume of distribution available •Volume of distribution (Drug B): Following a 1 mg parenteral dose, nalmefene was rapidly distributed. The apparent volumes of distribution centrally (V c ) and at steady-state (V dss ) are 3.9 ± 1.1 L/kg and 8.6 ± 1.7 L/kg, respectively. Nalmefene readily crosses the blood-brain barrier. •Protein binding (Drug A): In vitro tests show that bupropion is 84% bound to human plasma proteins at concentrations up to 200 mcg per mL. The extent of protein binding of the hydroxybupropion metabolite is similar to that for bupropion, whereas the extent of protein binding of the threohydrobupropion metabolite is about half that seen with bupropion. •Protein binding (Drug B): Protein binding of nalmefene ranges from 30% to 45%. In vitro, 67% (CV 8.7%) of nalmefene was distributed into red blood cells and 39% (CV 6.4%) was distributed into plasma. The whole blood to plasma ratio was 1.3 (CV 6.6%) over the nominal concentration range in whole blood from 0.376 to 30 ng/mL. •Metabolism (Drug A): Bupropion is extensively metabolized in humans. Three metabolites are active: hydroxybupropion, which is formed via hydroxylation of the tert-butyl group of bupropion, and the amino-alcohol isomers, threohydrobupropion and erythrohydrobupropion, which are formed via reduction of the carbonyl group. In vitro findings suggest that CYP2B6 is the principal isoenzyme involved in the formation of hydroxybupropion, while cytochrome P450 enzymes are not involved in the formation of threohydrobupropion. Hydroxybupropion has been shown to have the same affinity as bupropion for the norepinephrine transporter (NET) but approximately 50% of its antidepressant activity despite reaching concentrations of ~10-fold higher than that of the parent drug. Oxidation of the bupropion side chain results in the formation of a glycine conjugate of meta-chlorobenzoic acid, which is then excreted as the major urinary metabolite. The potency and toxicity of the metabolites relative to bupropion have not been fully characterized. However, it has been demonstrated in an antidepressant screening test in mice that hydroxybupropion is one-half as potent as bupropion, while threohydrobupropion and erythrohydrobupropion are 5-fold less potent than bupropion. This may be of clinical importance because the plasma concentrations of the metabolites are as high as or higher than those of bupropion. Bupropion and its metabolites exhibit linear kinetics following chronic administration of 300 to 450 mg per day. •Metabolism (Drug B): Nalmefene is extensively metabolized by the liver, primarily by glucuronide conjugation mainly mediated by UGT2B7 and UGT1A3 and UGT1A8 to a lesser extent. The major metabolite is pharmacologically inactive nalmefene 3-O-glucuronide. Nalmefene is also metabolized to trace amounts of an N-dealkylated metabolite, which has minimal pharmacological activity. Nalmefene can undergo dealkylation mediated by CYP3A4/5 to form nornalmefene. Nornalmefene can be further converted to nornalmefene 3-O-glucuronide and nornalmefene 3-sulfate, which are generally inactive metabolites. Nalmefene can also undergo CYP3A4/5-mediated sulfation to form nalmefene 3-O-sulfate, which retains some pharmacological activity. However, nalmefene 3-O-sulfate is present in the circulation in less than 10% of that of nalmefene; thus, it is unlikely to be a major contributor to the pharmacological activity of nalmefene. The plasma concentration-time profile in some subjects suggests that nalmefene undergoes enterohepatic recycling. •Route of elimination (Drug A): Bupropion is extensively metabolized in humans. Oxidation of the bupropion side chain results in the formation of a glycine conjugate of metachlorobenzoic acid, which is then excreted as the major urinary metabolite. Following oral administration of 200 mg of 14C-bupropion in humans, 87% and 10% of the radioactive dose were recovered in the urine and feces, respectively. However, the fraction of the oral dose of bupropion excreted unchanged was only 0.5%, a finding consistent with the extensive metabolism of bupropion. •Route of elimination (Drug B): Renal excretion is the main route of elimination for nalmefene and its metabolites. About 54% of the total dose is excreted in the urine as nalmefene 3-O-glucuronide. Less than 3% of the dose is excreted as nalmefene or other metabolites. About 17% of the dose is excreted in the feces. •Half-life (Drug A): 24 hours •Half-life (Drug B): The terminal half-life is approximately 12.5 hours following oral administration. After intravenous administration of 1 mg nalmefene to healthy adult male subjects, plasma concentrations declined biexponentially with redistribution and a terminal elimination half-life of 41 ± 34 minutes and 10.8 ± 5.2 hours, respectively. •Clearance (Drug A): No clearance available •Clearance (Drug B): The oral clearance of nalmefene (CL/F) was estimated as 169 L/h. Following intravenous administration of 1 mg nalmefene, the systemic clearance of nalmefene was 0.8 ± 0.2 L/hr/kg and the renal clearance was 0.08 ± 0.04 L/hr/kg. •Toxicity (Drug A): Symptoms of overdose include seizures, hallucinations, loss of consciousness, tachycardia, and cardiac arrest. •Toxicity (Drug B): The oral LD 50 values were 230 and <200 mg/kg for male and female mice, <300 and 150 mg/kg for male and female rats, and <225 and 225 for male and female rabbits. In mice, rats, and rabbits, intravenous LD 50 values had a range of 15.0-48.5 mg/kg and subcutaneous LD 50 values were in the range of 157-1150 mg/kg. Nalmefene was well tolerated and showed no serious toxicity during experimental administration to healthy individuals, even when given at 15 times the highest recommended dose. In a small number of subjects, at doses exceeding the recommended nalmefene injection dose, nalmefene produced symptoms suggestive of reversal of endogenous opioids, such as nausea, chills, myalgia, dysphoria, abdominal cramps, and joint pain. These symptoms can also arise in other narcotic antagonist drugs and they are usually transient in nature and occur at a very low frequency. Large doses of nalmefene have been used in studies. For example, one study used doses of nalmefene up to 90 mg/day for 16 weeks in patients diagnosed with pathological gambling. In a study in patients with interstitial cystitis, 20 patients received 108 mg/day of nalmefene for more than two years. Intake of a single dose of 450 mg nalmefene has been reported without changes in blood pressure, heart rate, respiration rate, or body temperature. There was no unusual pattern of adverse reactions, but the experience is limited. Management of an overdose should be observational and symptomatic. •Brand Names (Drug A): Aplenzin, Auvelity, Budeprion, Contrave, Forfivo, Wellbutrin, Zyban •Brand Names (Drug B): Opvee, Revex, Selincro •Synonyms (Drug A): No synonyms listed •Synonyms (Drug B): No synonyms listed •Summary (Drug A): Bupropion is a norepinephrine and dopamine reuptake inhibitor used in the treatment of major depressive disorder (MDD), seasonal affective disorder (SAD), and as an aid to smoking cessation. •Summary (Drug B): Nalmefene is an opioid antagonist used to reduce alcohol consumption in adults with alcohol dependence and treat and prevent opioid overdose.

The renal excretion of drugs is the overall result of a combination of kidney processes that include glomerular filtration, passive diffusion, tubular secretion, and tubular reabsorption. Since two of these mechanisms - tubular secretion and reabsorption - are saturable processes , they are consequently susceptible to competition between multiple substrates excreted by the kidneys. If two or more medications that are mainly renally excreted are co-administered, they may compete for renal elimination; there is a large likelihood that one agent may "out-compete" or saturate the renal excretion mechanisms before the other concomitantly administered agent(s) are excreted. As a result, the elimination of these other concurrently administered agents may be inhibited or otherwise delayed, which could lead to increases in their serum concentrations and the risk, incidence, and/or severity of adverse effects associated with the exposure to such drugs. The severity of the interaction is minor.

Question: Does Bupropion and Nalmefene interact? Information: •Drug A: Bupropion •Drug B: Nalmefene •Severity: MINOR •Description: Bupropion may decrease the excretion rate of Nalmefene which could result in a higher serum level. •Extended Description: The renal excretion of drugs is the overall result of a combination of kidney processes that include glomerular filtration, passive diffusion, tubular secretion, and tubular reabsorption. Since two of these mechanisms - tubular secretion and reabsorption - are saturable processes , they are consequently susceptible to competition between multiple substrates excreted by the kidneys. If two or more medications that are mainly renally excreted are co-administered, they may compete for renal elimination; there is a large likelihood that one agent may "out-compete" or saturate the renal excretion mechanisms before the other concomitantly administered agent(s) are excreted. As a result, the elimination of these other concurrently administered agents may be inhibited or otherwise delayed, which could lead to increases in their serum concentrations and the risk, incidence, and/or severity of adverse effects associated with the exposure to such drugs. •Indication (Drug A): Bupropion is indicated for the treatment of major depressive disorder (MDD), seasonal affective disorder (SAD), and as an aid to smoking cessation. When used in combination with naltrexone as the marketed product ContraveⓇ, bupropion is indicated as an adjunct to a reduced-calorie diet and increased physical activity for chronic weight management in adults with an initial body mass index (BMI) of: 30 kg/m^2 or greater (obese) or 27 kg/m^2 or greater (overweight) in the presence of at least one weight-related comorbid condition (e.g., hypertension, type 2 diabetes mellitus, or dyslipidemia). Bupropion is also used off-label as a first-line treatment in patients with ADHD and comorbid bipolar disorder when used as an adjunct to mood stabilizers. •Indication (Drug B): Nalmefene oral tablet is indicated for the reduction of alcohol consumption in adult patients with alcohol dependence who have a high drinking risk level (DRL), without physical withdrawal symptoms and who do not require immediate detoxification. Nalmefene should only be prescribed in conjunction with continuous psychosocial support focused on treatment adherence and reducing alcohol consumption. Nalmefene should be initiated only in patients who continue to have a high DRL two weeks after the initial assessment. Nalmefene injection and nasal spray are indicated for the complete or partial reversal of opioid drug effects, including respiratory depression, induced by either natural or synthetic opioids. They are also indicated in the management of known or suspected opioid overdose. Nalmefene injection can be used for postoperative opioid overdose reversal. •Pharmacodynamics (Drug A): Bupropion is chemically unrelated to tricyclic, tetracyclic, selective serotonin re-uptake inhibitors, or other known antidepressant agents. Compared to classical tricyclic antidepressants, Bupropion is a relatively weak inhibitor of the neuronal uptake of norepinephrine and dopamine. In addition, Bupropion does not inhibit monoamine oxidase. Bupropion has been found to be essentially inactive at the serotonin transporter (SERT)(IC50 >10 000 nM), however both bupropion and its primary metabolite hydroxybupropion have been found to block the function of cation-selective serotonin type 3A receptors (5-HT3ARs). Bupropion produces dose-related central nervous system (CNS) stimulant effects in animals, as evidenced by increased locomotor activity, increased rates of responding in various schedule-controlled operant behaviour tasks, and, at high doses, induction of mild stereotyped behaviour. Due to these stimulant effects and selective activity at dopamine and norepinephrine receptors, bupropion has been identified as having an abuse potential. Bupropion has a similar structure to the controlled substance Cathinone, and has been identified as having mild amphetamine-like activity, particularly when inhaled or injected. Bupropion is also known to lower the seizure threshold, making any pre-existing seizure conditions a contraindication to its use. This risk is exacerbated when bupropion is combined with other drugs or substances that lower the seizure threshold, such as cocaine, or in clinical situations that would increase the risk of a seizure such as abrupt alcohol or benzodiazepine withdrawal. As norepinephrine has been shown to have anticonvulsant properties, bupropion's inhibitory effects on NET are thought to contribute to its pro-convulsant activity. Bupropion has been shown to increase blood pressure and pose a risk for exacerbation of unmanaged or pre-existing hypertension, however, clinical trials of bupropion in smokers with CVD have not identified an increased incidence of CV events including stroke or heart attack. In clinical trials, the mean increase in systolic blood pressure associated with the use of bupropion was found to be 1.3 mmHg. •Pharmacodynamics (Drug B): Nalmefene is an opioid antagonist with no agonist activity. It works to prevent or reverse the effects of opioids, including respiratory depression, sedation, and hypotension. Nalmefene has a longer duration of action than naloxone, another opioid antagonist used to reverse opioid overdose. In a study of brain receptor occupancy, a 1 mg dose of nalmefene blocked over 80% of brain opioid receptors within five minutes after administration. Nalmefene has no opioid agonist activity and it is not associated with drug tolerance, physical dependence, or abuse potential. Nalmefene is not known to produce respiratory depression, psychotomimetic effects, or pupillary constriction. No pharmacological activity was observed when nalmefene was administered in the absence of opioid agonists. However, as with all opioid antagonists, nalmefene can produce acute withdrawal symptoms in individuals with opioid dependence. These withdrawal symptoms should be managed with symptomatic and supportive treatment: the administration of large amounts of opioids to patients receiving opioid antagonists in an attempt to overcome a full blockade has resulted in adverse respiratory and circulatory reactions. •Mechanism of action (Drug A): Bupropion is a norepinephrine/dopamine-reuptake inhibitor (NDRI) that exerts its pharmacological effects by weakly inhibiting the enzymes involved in the uptake of the neurotransmitters norepinephrine and dopamine from the synaptic cleft, therefore prolonging their duration of action within the neuronal synapse and the downstream effects of these neurotransmitters. More specifically, bupropion binds to the norepinephrine transporter (NET) and the dopamine transporter (DAT). Bupropion was originally classified as an "atypical" antidepressant because it does not exert the same effects as the classical antidepressants such as Monoamine Oxidase Inhibitors (MAOIs), Tricyclic Antidepressants (TCAs), or Selective Serotonin Reuptake Inhibitors (SSRIs). While it has comparable effectiveness to typical first-line options for the treatment of depression such as SSRIs, bupropion is a unique option for the treatment of MDD as it lacks any clinically relevant serotonergic effects, typical of other mood medications, or any effects on histamine or adrenaline receptors. Lack of activity at these receptors results in a more tolerable side effect profile; bupropion is less likely to cause sexual side effects, sedation, or weight gain as compared to SSRIs or TCAs, for example. When used as an aid to smoking cessation, bupropion is thought to confer its anti-craving and anti-withdrawal effects by inhibiting dopamine reuptake, which is thought to be involved in the reward pathways associated with nicotine, and through the antagonism of the nicotinic acetylcholinergic receptor (AChR), thereby blunting the effects of nicotine. Furthermore, the stimulatory effects produced by bupropion in the central nervous system are similar to nicotine's effects, making low doses of bupropion a suitable option as a nicotine substitute. When used in combination with naltrexone in the marketed product ContraveⓇ for chronic weight management, the two components are thought to have effects on areas of the brain involved in the regulation of food intake. This includes the hypothalamus, which is involved in appetite regulation, and the mesolimbic dopamine circuit, which is involved in reward pathways. Studies have shown that the combined activity of bupropion and naltrexone increase the firing rate of hypothalamic pro-opiomelanocortin (POMC) neurons and blockade of opioid receptor-mediated POMC auto-inhibition, which are associated with a reduction in food intake and increased energy expenditure. This combination was also found to reduce food intake when injected directly into the ventral tegmental area of the mesolimbic circuit in mice, which is an area associated with the regulation of reward pathways. •Mechanism of action (Drug B): The opioid system consists of three opioid receptors - mu (μ), delta (δ), and kappa (κ) - that are G-protein coupled receptors. Opioid receptors are activated by endogenous opioid peptides and are expressed throughout the brain to play a critical role in mood regulation, pain, reward, addictive behaviours, and substance use disorders. Opioid receptors are involved in various brain signalling pathways, including the mesolimbic pathway, sometimes referred to as the reward pathway. The mesolimbic pathway plays an important role in the positive reinforcement of natural rewards like food and drugs of abuse like exogenous opioid drugs. Many abused drugs activate mu-opioid receptors, leading to positive reinforcing effects. Alcohol consumption can also cause the release of endogenous opioids, which bind to mu and delta receptors, thereby increasing the release of dopamine in the nucleus accumbens to induce reward and positive reinforcement effects. Nalmefene is an antagonist at the mu and delta-opioid receptors and a partial agonist at the kappa-opioid receptor. As an antagonist, nalmefene blocks ligands from binding to the opioid receptor. Animal studies suggest that kappa-opioid receptor signalling blocks acute reward and positive reinforcement effects of drugs with abusive potential by decreasing dopamine in the nucleus accumbens. In vivo studies have demonstrated that nalmefene reduces alcohol consumption, possibly by modulating cortico-mesolimbic functions. Preclinical studies suggest that nalmefene restores alcohol-induced dysregulations of the MOR/endorphins and the KOR/dynorphin system. •Absorption (Drug A): Bupropion is currently available in 3 distinct, but bioequivalent formulations: immediate release (IR), sustained-release (SR), and extended-release (XL). Immediate Release Formulation In humans, following oral administration of bupropion hydrochloride tablets, peak plasma bupropion concentrations are usually achieved within 2 hours. IR formulations provide a short duration of action and are therefore generally dosed three times per day. Sustained Release Formulation In humans, following oral administration of bupropion hydrochloride sustained-release tablets (SR), peak plasma concentration (Cmax) of bupropion is usually achieved within 3 hours. SR formulations provide a 12-hour extended release of medication and are therefore generally dosed twice per day. Extended Release Formulation Following single oral administration of bupropion hydrochloride extended-release tablets (XL) to healthy volunteers, the median time to peak plasma concentrations for bupropion was approximately 5 hours. The presence of food did not affect the peak concentration or area under the curve of bupropion. XL formulations provide a 24-hour extended release of medication and are therefore generally dosed once per day/ In a trial comparing chronic dosing with bupropion hydrochloride extended-release tablets (SR) 150 mg twice daily to bupropion immediate-release formulation 100 mg 3 times daily, the steady state Cmax for bupropion after bupropion hydrochloride sustained-release tablets (SR) administration was approximately 85% of those achieved after bupropion immediate-release formulation administration. Exposure (AUC) to bupropion was equivalent for both formulations. Bioequivalence was also demonstrated for all three major active metabolites (i.e., hydroxybupropion, threohydrobupropion and erythrohydrobupropion) for both Cmax and AUC. Thus, at steady state, bupropion hydrochloride sustained-release tablets (SR) given twice daily, and the immediate-release formulation of bupropion given 3 times daily, are essentially bioequivalent for both bupropion and the 3 quantitatively important metabolites. Furthermore, in a study comparing 14-day dosing with bupropion hydrochloride extended-release tablets (XL), 300 mg once-daily to the immediate-release formulation of bupropion at 100 mg 3 times daily, equivalence was demonstrated for peak plasma concentration and area under the curve for bupropion and the three metabolites (hydroxybupropion, threohydrobupropion, and erythrohydrobupropion). Additionally, in a study comparing 14-day dosing with bupropion hydrochloride extended-release tablets (XL) 300 mg once daily to the sustained-release formulation of bupropion at 150 mg 2 times daily, equivalence was demonstrated for peak plasma concentration and area under the curve for bupropion and the three metabolites. Bupropion hydrochloride extended-release tablets (SR) can be taken with or without food. Bupropion Cmax and AUC were increased by 11% to 35% and 16% to 19%, respectively, when bupropion hydrochloride extended-release tablets (SR) was administered with food to healthy volunteers in three trials. The food effect is not considered clinically significant. Following a single-dose administration of bupropion hydrochloride extended-release tablets (SR) in humans, Cmax of bupropion's metabolite hydroxybupropion occurs approximately 6 hours post-dose and is approximately 10 times the peak level of the parent drug at steady state. The elimination half-life of hydroxybupropion is approximately 20 (±5) hours and its AUC at steady state is about 17 times that of bupropion. The times to peak concentrations for the erythrohydrobupropion and threohydrobupropion metabolites are similar to that of the hydroxybupropion metabolite. However, their elimination half-lives are longer, 33(±10) and 37 (±13) hours, respectively, and steady-state AUCs are 1.5 and 7 times that of bupropion, respectively. •Absorption (Drug B): Nalmefene is rapidly absorbed after a single oral administration of 18.06 mg with an absolute oral bioavailability of 41%. The C max was 16.5 ng/mL and T max was approximately 1.5 hours. The exposure (AUC) was 131 ng x h/mL. High-fat meal increased the AUC by 30% and C max by 50% and delayed T max by 30 min; however, this is unlikely of clinical significance. Nalmefene exhibits dose-proportional pharmacokinetics following intravenous administration of 0.5 mg to 2 mg. T max was 2.3 ± 1.1 hours following intramuscular administration and 1.5 ± 1.2 hours following subcutaneous administration. Therapeutic plasma concentrations are likely to be reached within 5 to 15 minutes after a 1 mg dose in an emergency. There is variability in the speed of absorption for intramuscular and subcutaneous dosing. •Volume of distribution (Drug A): No volume of distribution available •Volume of distribution (Drug B): Following a 1 mg parenteral dose, nalmefene was rapidly distributed. The apparent volumes of distribution centrally (V c ) and at steady-state (V dss ) are 3.9 ± 1.1 L/kg and 8.6 ± 1.7 L/kg, respectively. Nalmefene readily crosses the blood-brain barrier. •Protein binding (Drug A): In vitro tests show that bupropion is 84% bound to human plasma proteins at concentrations up to 200 mcg per mL. The extent of protein binding of the hydroxybupropion metabolite is similar to that for bupropion, whereas the extent of protein binding of the threohydrobupropion metabolite is about half that seen with bupropion. •Protein binding (Drug B): Protein binding of nalmefene ranges from 30% to 45%. In vitro, 67% (CV 8.7%) of nalmefene was distributed into red blood cells and 39% (CV 6.4%) was distributed into plasma. The whole blood to plasma ratio was 1.3 (CV 6.6%) over the nominal concentration range in whole blood from 0.376 to 30 ng/mL. •Metabolism (Drug A): Bupropion is extensively metabolized in humans. Three metabolites are active: hydroxybupropion, which is formed via hydroxylation of the tert-butyl group of bupropion, and the amino-alcohol isomers, threohydrobupropion and erythrohydrobupropion, which are formed via reduction of the carbonyl group. In vitro findings suggest that CYP2B6 is the principal isoenzyme involved in the formation of hydroxybupropion, while cytochrome P450 enzymes are not involved in the formation of threohydrobupropion. Hydroxybupropion has been shown to have the same affinity as bupropion for the norepinephrine transporter (NET) but approximately 50% of its antidepressant activity despite reaching concentrations of ~10-fold higher than that of the parent drug. Oxidation of the bupropion side chain results in the formation of a glycine conjugate of meta-chlorobenzoic acid, which is then excreted as the major urinary metabolite. The potency and toxicity of the metabolites relative to bupropion have not been fully characterized. However, it has been demonstrated in an antidepressant screening test in mice that hydroxybupropion is one-half as potent as bupropion, while threohydrobupropion and erythrohydrobupropion are 5-fold less potent than bupropion. This may be of clinical importance because the plasma concentrations of the metabolites are as high as or higher than those of bupropion. Bupropion and its metabolites exhibit linear kinetics following chronic administration of 300 to 450 mg per day. •Metabolism (Drug B): Nalmefene is extensively metabolized by the liver, primarily by glucuronide conjugation mainly mediated by UGT2B7 and UGT1A3 and UGT1A8 to a lesser extent. The major metabolite is pharmacologically inactive nalmefene 3-O-glucuronide. Nalmefene is also metabolized to trace amounts of an N-dealkylated metabolite, which has minimal pharmacological activity. Nalmefene can undergo dealkylation mediated by CYP3A4/5 to form nornalmefene. Nornalmefene can be further converted to nornalmefene 3-O-glucuronide and nornalmefene 3-sulfate, which are generally inactive metabolites. Nalmefene can also undergo CYP3A4/5-mediated sulfation to form nalmefene 3-O-sulfate, which retains some pharmacological activity. However, nalmefene 3-O-sulfate is present in the circulation in less than 10% of that of nalmefene; thus, it is unlikely to be a major contributor to the pharmacological activity of nalmefene. The plasma concentration-time profile in some subjects suggests that nalmefene undergoes enterohepatic recycling. •Route of elimination (Drug A): Bupropion is extensively metabolized in humans. Oxidation of the bupropion side chain results in the formation of a glycine conjugate of metachlorobenzoic acid, which is then excreted as the major urinary metabolite. Following oral administration of 200 mg of 14C-bupropion in humans, 87% and 10% of the radioactive dose were recovered in the urine and feces, respectively. However, the fraction of the oral dose of bupropion excreted unchanged was only 0.5%, a finding consistent with the extensive metabolism of bupropion. •Route of elimination (Drug B): Renal excretion is the main route of elimination for nalmefene and its metabolites. About 54% of the total dose is excreted in the urine as nalmefene 3-O-glucuronide. Less than 3% of the dose is excreted as nalmefene or other metabolites. About 17% of the dose is excreted in the feces. •Half-life (Drug A): 24 hours •Half-life (Drug B): The terminal half-life is approximately 12.5 hours following oral administration. After intravenous administration of 1 mg nalmefene to healthy adult male subjects, plasma concentrations declined biexponentially with redistribution and a terminal elimination half-life of 41 ± 34 minutes and 10.8 ± 5.2 hours, respectively. •Clearance (Drug A): No clearance available •Clearance (Drug B): The oral clearance of nalmefene (CL/F) was estimated as 169 L/h. Following intravenous administration of 1 mg nalmefene, the systemic clearance of nalmefene was 0.8 ± 0.2 L/hr/kg and the renal clearance was 0.08 ± 0.04 L/hr/kg. •Toxicity (Drug A): Symptoms of overdose include seizures, hallucinations, loss of consciousness, tachycardia, and cardiac arrest. •Toxicity (Drug B): The oral LD 50 values were 230 and <200 mg/kg for male and female mice, <300 and 150 mg/kg for male and female rats, and <225 and 225 for male and female rabbits. In mice, rats, and rabbits, intravenous LD 50 values had a range of 15.0-48.5 mg/kg and subcutaneous LD 50 values were in the range of 157-1150 mg/kg. Nalmefene was well tolerated and showed no serious toxicity during experimental administration to healthy individuals, even when given at 15 times the highest recommended dose. In a small number of subjects, at doses exceeding the recommended nalmefene injection dose, nalmefene produced symptoms suggestive of reversal of endogenous opioids, such as nausea, chills, myalgia, dysphoria, abdominal cramps, and joint pain. These symptoms can also arise in other narcotic antagonist drugs and they are usually transient in nature and occur at a very low frequency. Large doses of nalmefene have been used in studies. For example, one study used doses of nalmefene up to 90 mg/day for 16 weeks in patients diagnosed with pathological gambling. In a study in patients with interstitial cystitis, 20 patients received 108 mg/day of nalmefene for more than two years. Intake of a single dose of 450 mg nalmefene has been reported without changes in blood pressure, heart rate, respiration rate, or body temperature. There was no unusual pattern of adverse reactions, but the experience is limited. Management of an overdose should be observational and symptomatic. •Brand Names (Drug A): Aplenzin, Auvelity, Budeprion, Contrave, Forfivo, Wellbutrin, Zyban •Brand Names (Drug B): Opvee, Revex, Selincro •Synonyms (Drug A): No synonyms listed •Synonyms (Drug B): No synonyms listed •Summary (Drug A): Bupropion is a norepinephrine and dopamine reuptake inhibitor used in the treatment of major depressive disorder (MDD), seasonal affective disorder (SAD), and as an aid to smoking cessation. •Summary (Drug B): Nalmefene is an opioid antagonist used to reduce alcohol consumption in adults with alcohol dependence and treat and prevent opioid overdose. Output: The renal excretion of drugs is the overall result of a combination of kidney processes that include glomerular filtration, passive diffusion, tubular secretion, and tubular reabsorption. Since two of these mechanisms - tubular secretion and reabsorption - are saturable processes , they are consequently susceptible to competition between multiple substrates excreted by the kidneys. If two or more medications that are mainly renally excreted are co-administered, they may compete for renal elimination; there is a large likelihood that one agent may "out-compete" or saturate the renal excretion mechanisms before the other concomitantly administered agent(s) are excreted. As a result, the elimination of these other concurrently administered agents may be inhibited or otherwise delayed, which could lead to increases in their serum concentrations and the risk, incidence, and/or severity of adverse effects associated with the exposure to such drugs. The severity of the interaction is minor.

Does Bupropion and Naloxone interact?

•Drug A: Bupropion •Drug B: Naloxone •Severity: MINOR •Description: Bupropion may decrease the excretion rate of Naloxone which could result in a higher serum level. •Extended Description: The renal excretion of drugs is the overall result of a combination of kidney processes that include glomerular filtration, passive diffusion, tubular secretion, and tubular reabsorption. Since two of these mechanisms - tubular secretion and reabsorption - are saturable processes , they are consequently susceptible to competition between multiple substrates excreted by the kidneys. If two or more medications that are mainly renally excreted are co-administered, they may compete for renal elimination; there is a large likelihood that one agent may "out-compete" or saturate the renal excretion mechanisms before the other concomitantly administered agent(s) are excreted. As a result, the elimination of these other concurrently administered agents may be inhibited or otherwise delayed, which could lead to increases in their serum concentrations and the risk, incidence, and/or severity of adverse effects associated with the exposure to such drugs. •Indication (Drug A): Bupropion is indicated for the treatment of major depressive disorder (MDD), seasonal affective disorder (SAD), and as an aid to smoking cessation. When used in combination with naltrexone as the marketed product ContraveⓇ, bupropion is indicated as an adjunct to a reduced-calorie diet and increased physical activity for chronic weight management in adults with an initial body mass index (BMI) of: 30 kg/m^2 or greater (obese) or 27 kg/m^2 or greater (overweight) in the presence of at least one weight-related comorbid condition (e.g., hypertension, type 2 diabetes mellitus, or dyslipidemia). Bupropion is also used off-label as a first-line treatment in patients with ADHD and comorbid bipolar disorder when used as an adjunct to mood stabilizers. •Indication (Drug B): Naloxone nasal sprays are indicated for the reversal of an opioid overdose or suspected opioid overdose: it is intended for immediate administration as emergency therapy in settings where opioids may be present. Intramuscular, intravenous, and subcutaneous injections are indicated for complete or partial reversal of opioid depression, diagnosis of known or suspected opioid overdose, and as an adjunct therapy in the treatment of septic shock. Sublingual tablets and films are formulated with buprenorphine for the treatment of opioid dependence. Naloxone is also formulated with pentazocine as an oral tablet for severe pain. Intramuscular or subcutaneous naloxone autoinjectors are used for the emergency treatment of people 12 years of age and older where the use of high-potency opioids such as fentanyl analogues as a chemical weapon, is suspected. Naloxone has been used off-label for the treatment of neuraxial opioid-induced pruritus. •Pharmacodynamics (Drug A): Bupropion is chemically unrelated to tricyclic, tetracyclic, selective serotonin re-uptake inhibitors, or other known antidepressant agents. Compared to classical tricyclic antidepressants, Bupropion is a relatively weak inhibitor of the neuronal uptake of norepinephrine and dopamine. In addition, Bupropion does not inhibit monoamine oxidase. Bupropion has been found to be essentially inactive at the serotonin transporter (SERT)(IC50 >10 000 nM), however both bupropion and its primary metabolite hydroxybupropion have been found to block the function of cation-selective serotonin type 3A receptors (5-HT3ARs). Bupropion produces dose-related central nervous system (CNS) stimulant effects in animals, as evidenced by increased locomotor activity, increased rates of responding in various schedule-controlled operant behaviour tasks, and, at high doses, induction of mild stereotyped behaviour. Due to these stimulant effects and selective activity at dopamine and norepinephrine receptors, bupropion has been identified as having an abuse potential. Bupropion has a similar structure to the controlled substance Cathinone, and has been identified as having mild amphetamine-like activity, particularly when inhaled or injected. Bupropion is also known to lower the seizure threshold, making any pre-existing seizure conditions a contraindication to its use. This risk is exacerbated when bupropion is combined with other drugs or substances that lower the seizure threshold, such as cocaine, or in clinical situations that would increase the risk of a seizure such as abrupt alcohol or benzodiazepine withdrawal. As norepinephrine has been shown to have anticonvulsant properties, bupropion's inhibitory effects on NET are thought to contribute to its pro-convulsant activity. Bupropion has been shown to increase blood pressure and pose a risk for exacerbation of unmanaged or pre-existing hypertension, however, clinical trials of bupropion in smokers with CVD have not identified an increased incidence of CV events including stroke or heart attack. In clinical trials, the mean increase in systolic blood pressure associated with the use of bupropion was found to be 1.3 mmHg. •Pharmacodynamics (Drug B): Naloxone is an opioid receptor antagonist indicated in the reversal of opioid overdoses. Naloxone has a shorter duration of action than opioids and multiple doses may be required. The therapeutic window of naloxone is wide, as it has no effect if a patient has not taken opioids. Patients treated with naloxone may experience opioid withdrawal and a person administering naloxone should be aware that reversal of opioid overdoses may not resolve all the symptoms a patient is experiencing if other drugs are involved. •Mechanism of action (Drug A): Bupropion is a norepinephrine/dopamine-reuptake inhibitor (NDRI) that exerts its pharmacological effects by weakly inhibiting the enzymes involved in the uptake of the neurotransmitters norepinephrine and dopamine from the synaptic cleft, therefore prolonging their duration of action within the neuronal synapse and the downstream effects of these neurotransmitters. More specifically, bupropion binds to the norepinephrine transporter (NET) and the dopamine transporter (DAT). Bupropion was originally classified as an "atypical" antidepressant because it does not exert the same effects as the classical antidepressants such as Monoamine Oxidase Inhibitors (MAOIs), Tricyclic Antidepressants (TCAs), or Selective Serotonin Reuptake Inhibitors (SSRIs). While it has comparable effectiveness to typical first-line options for the treatment of depression such as SSRIs, bupropion is a unique option for the treatment of MDD as it lacks any clinically relevant serotonergic effects, typical of other mood medications, or any effects on histamine or adrenaline receptors. Lack of activity at these receptors results in a more tolerable side effect profile; bupropion is less likely to cause sexual side effects, sedation, or weight gain as compared to SSRIs or TCAs, for example. When used as an aid to smoking cessation, bupropion is thought to confer its anti-craving and anti-withdrawal effects by inhibiting dopamine reuptake, which is thought to be involved in the reward pathways associated with nicotine, and through the antagonism of the nicotinic acetylcholinergic receptor (AChR), thereby blunting the effects of nicotine. Furthermore, the stimulatory effects produced by bupropion in the central nervous system are similar to nicotine's effects, making low doses of bupropion a suitable option as a nicotine substitute. When used in combination with naltrexone in the marketed product ContraveⓇ for chronic weight management, the two components are thought to have effects on areas of the brain involved in the regulation of food intake. This includes the hypothalamus, which is involved in appetite regulation, and the mesolimbic dopamine circuit, which is involved in reward pathways. Studies have shown that the combined activity of bupropion and naltrexone increase the firing rate of hypothalamic pro-opiomelanocortin (POMC) neurons and blockade of opioid receptor-mediated POMC auto-inhibition, which are associated with a reduction in food intake and increased energy expenditure. This combination was also found to reduce food intake when injected directly into the ventral tegmental area of the mesolimbic circuit in mice, which is an area associated with the regulation of reward pathways. •Mechanism of action (Drug B): Naloxone is a competitive inhibitor of the µ-opioid receptor. Naloxone antagonizes the action of opioids, reversing their effects. If a patient has not taken opioids, naloxone does not have a significant effect on patients. •Absorption (Drug A): Bupropion is currently available in 3 distinct, but bioequivalent formulations: immediate release (IR), sustained-release (SR), and extended-release (XL). Immediate Release Formulation In humans, following oral administration of bupropion hydrochloride tablets, peak plasma bupropion concentrations are usually achieved within 2 hours. IR formulations provide a short duration of action and are therefore generally dosed three times per day. Sustained Release Formulation In humans, following oral administration of bupropion hydrochloride sustained-release tablets (SR), peak plasma concentration (Cmax) of bupropion is usually achieved within 3 hours. SR formulations provide a 12-hour extended release of medication and are therefore generally dosed twice per day. Extended Release Formulation Following single oral administration of bupropion hydrochloride extended-release tablets (XL) to healthy volunteers, the median time to peak plasma concentrations for bupropion was approximately 5 hours. The presence of food did not affect the peak concentration or area under the curve of bupropion. XL formulations provide a 24-hour extended release of medication and are therefore generally dosed once per day/ In a trial comparing chronic dosing with bupropion hydrochloride extended-release tablets (SR) 150 mg twice daily to bupropion immediate-release formulation 100 mg 3 times daily, the steady state Cmax for bupropion after bupropion hydrochloride sustained-release tablets (SR) administration was approximately 85% of those achieved after bupropion immediate-release formulation administration. Exposure (AUC) to bupropion was equivalent for both formulations. Bioequivalence was also demonstrated for all three major active metabolites (i.e., hydroxybupropion, threohydrobupropion and erythrohydrobupropion) for both Cmax and AUC. Thus, at steady state, bupropion hydrochloride sustained-release tablets (SR) given twice daily, and the immediate-release formulation of bupropion given 3 times daily, are essentially bioequivalent for both bupropion and the 3 quantitatively important metabolites. Furthermore, in a study comparing 14-day dosing with bupropion hydrochloride extended-release tablets (XL), 300 mg once-daily to the immediate-release formulation of bupropion at 100 mg 3 times daily, equivalence was demonstrated for peak plasma concentration and area under the curve for bupropion and the three metabolites (hydroxybupropion, threohydrobupropion, and erythrohydrobupropion). Additionally, in a study comparing 14-day dosing with bupropion hydrochloride extended-release tablets (XL) 300 mg once daily to the sustained-release formulation of bupropion at 150 mg 2 times daily, equivalence was demonstrated for peak plasma concentration and area under the curve for bupropion and the three metabolites. Bupropion hydrochloride extended-release tablets (SR) can be taken with or without food. Bupropion Cmax and AUC were increased by 11% to 35% and 16% to 19%, respectively, when bupropion hydrochloride extended-release tablets (SR) was administered with food to healthy volunteers in three trials. The food effect is not considered clinically significant. Following a single-dose administration of bupropion hydrochloride extended-release tablets (SR) in humans, Cmax of bupropion's metabolite hydroxybupropion occurs approximately 6 hours post-dose and is approximately 10 times the peak level of the parent drug at steady state. The elimination half-life of hydroxybupropion is approximately 20 (±5) hours and its AUC at steady state is about 17 times that of bupropion. The times to peak concentrations for the erythrohydrobupropion and threohydrobupropion metabolites are similar to that of the hydroxybupropion metabolite. However, their elimination half-lives are longer, 33(±10) and 37 (±13) hours, respectively, and steady-state AUCs are 1.5 and 7 times that of bupropion, respectively. •Absorption (Drug B): An intranasal dose of naloxone is 42-47% bioavailable. An 8 mg dose of nasal naloxone reaches a C max of 12.3-12.8 ng/mL, with a T max of 0.25 hours, and an AUC of 16.7-19.0 h*ng/mL. A 0.4 mg intramuscular dose reaches a C max of 0.876-0.910 ng/mL, with a T max of 0.25 hours, and an AUC of 1.94-1.95 h*ng/mL. A 2 mg intravenous dose reaches a C max of 26.2 ng/mL with an AUC of 12.8 h*ng/mL. •Volume of distribution (Drug A): No volume of distribution available •Volume of distribution (Drug B): The volume of distribution of naloxone is 200 L. Naloxone distributes into tissues rapidly. It can also cross the placenta and blood-brain barrier. •Protein binding (Drug A): In vitro tests show that bupropion is 84% bound to human plasma proteins at concentrations up to 200 mcg per mL. The extent of protein binding of the hydroxybupropion metabolite is similar to that for bupropion, whereas the extent of protein binding of the threohydrobupropion metabolite is about half that seen with bupropion. •Protein binding (Drug B): Naloxone is approximately 45% bound to albumin, but there is significant binding to other proteins. •Metabolism (Drug A): Bupropion is extensively metabolized in humans. Three metabolites are active: hydroxybupropion, which is formed via hydroxylation of the tert-butyl group of bupropion, and the amino-alcohol isomers, threohydrobupropion and erythrohydrobupropion, which are formed via reduction of the carbonyl group. In vitro findings suggest that CYP2B6 is the principal isoenzyme involved in the formation of hydroxybupropion, while cytochrome P450 enzymes are not involved in the formation of threohydrobupropion. Hydroxybupropion has been shown to have the same affinity as bupropion for the norepinephrine transporter (NET) but approximately 50% of its antidepressant activity despite reaching concentrations of ~10-fold higher than that of the parent drug. Oxidation of the bupropion side chain results in the formation of a glycine conjugate of meta-chlorobenzoic acid, which is then excreted as the major urinary metabolite. The potency and toxicity of the metabolites relative to bupropion have not been fully characterized. However, it has been demonstrated in an antidepressant screening test in mice that hydroxybupropion is one-half as potent as bupropion, while threohydrobupropion and erythrohydrobupropion are 5-fold less potent than bupropion. This may be of clinical importance because the plasma concentrations of the metabolites are as high as or higher than those of bupropion. Bupropion and its metabolites exhibit linear kinetics following chronic administration of 300 to 450 mg per day. •Metabolism (Drug B): Naloxone primarily undergoes glucuronidation to form naloxone-3-glucuronide. Naloxone is also N-dealkylated to noroxymorphone or undergoes 6-keto reduction to naloxol. •Route of elimination (Drug A): Bupropion is extensively metabolized in humans. Oxidation of the bupropion side chain results in the formation of a glycine conjugate of metachlorobenzoic acid, which is then excreted as the major urinary metabolite. Following oral administration of 200 mg of 14C-bupropion in humans, 87% and 10% of the radioactive dose were recovered in the urine and feces, respectively. However, the fraction of the oral dose of bupropion excreted unchanged was only 0.5%, a finding consistent with the extensive metabolism of bupropion. •Route of elimination (Drug B): After oral or intravenous administration, naloxone is 25-40% eliminated in the urine within 6 hours, 50% in 24 hours, and 60-70% in 72 hours. The metabolites naloxone-3-glucuronide, noroxymorphone, and naloxol are all detected in the urine. •Half-life (Drug A): 24 hours •Half-life (Drug B): The mean half life of naloxone hydrochloride is 1.8-2.7 hours intranasally, 1.4 hours intramuscularly, and 1.2 hours intravenously. In neonates, the mean half life is 3.1 ± 0.5 hours. •Clearance (Drug A): No clearance available •Clearance (Drug B): The clearance of naloxone is 2500 L/day. •Toxicity (Drug A): Symptoms of overdose include seizures, hallucinations, loss of consciousness, tachycardia, and cardiac arrest. •Toxicity (Drug B): If a patient has not taken opioids, naloxone does not have a significant effect on patients. The oral LD 50 in mice and rats is >1 g/kg. The intraperitoneal LD 50 is 80 mg/kg in mice and 239 mg/kg in rats. The subcutaneous LD 50 is 286 mg/kg in mice and 500 mg/kg in rats. •Brand Names (Drug A): Aplenzin, Auvelity, Budeprion, Contrave, Forfivo, Wellbutrin, Zyban •Brand Names (Drug B): Kloxxado, Narcan, Suboxone, Targin, Targiniq, Zimhi, Zubsolv •Synonyms (Drug A): No synonyms listed •Synonyms (Drug B): Nalossone Naloxona Naloxone Naloxonum •Summary (Drug A): Bupropion is a norepinephrine and dopamine reuptake inhibitor used in the treatment of major depressive disorder (MDD), seasonal affective disorder (SAD), and as an aid to smoking cessation. •Summary (Drug B): Naloxone is an opioid receptor antagonist used to rapidly reverse an opioid overdose. Also included in some drug formulations as an abuse deterrent to prevent injection.

The renal excretion of drugs is the overall result of a combination of kidney processes that include glomerular filtration, passive diffusion, tubular secretion, and tubular reabsorption. Since two of these mechanisms - tubular secretion and reabsorption - are saturable processes , they are consequently susceptible to competition between multiple substrates excreted by the kidneys. If two or more medications that are mainly renally excreted are co-administered, they may compete for renal elimination; there is a large likelihood that one agent may "out-compete" or saturate the renal excretion mechanisms before the other concomitantly administered agent(s) are excreted. As a result, the elimination of these other concurrently administered agents may be inhibited or otherwise delayed, which could lead to increases in their serum concentrations and the risk, incidence, and/or severity of adverse effects associated with the exposure to such drugs. The severity of the interaction is minor.

Question: Does Bupropion and Naloxone interact? Information: •Drug A: Bupropion •Drug B: Naloxone •Severity: MINOR •Description: Bupropion may decrease the excretion rate of Naloxone which could result in a higher serum level. •Extended Description: The renal excretion of drugs is the overall result of a combination of kidney processes that include glomerular filtration, passive diffusion, tubular secretion, and tubular reabsorption. Since two of these mechanisms - tubular secretion and reabsorption - are saturable processes , they are consequently susceptible to competition between multiple substrates excreted by the kidneys. If two or more medications that are mainly renally excreted are co-administered, they may compete for renal elimination; there is a large likelihood that one agent may "out-compete" or saturate the renal excretion mechanisms before the other concomitantly administered agent(s) are excreted. As a result, the elimination of these other concurrently administered agents may be inhibited or otherwise delayed, which could lead to increases in their serum concentrations and the risk, incidence, and/or severity of adverse effects associated with the exposure to such drugs. •Indication (Drug A): Bupropion is indicated for the treatment of major depressive disorder (MDD), seasonal affective disorder (SAD), and as an aid to smoking cessation. When used in combination with naltrexone as the marketed product ContraveⓇ, bupropion is indicated as an adjunct to a reduced-calorie diet and increased physical activity for chronic weight management in adults with an initial body mass index (BMI) of: 30 kg/m^2 or greater (obese) or 27 kg/m^2 or greater (overweight) in the presence of at least one weight-related comorbid condition (e.g., hypertension, type 2 diabetes mellitus, or dyslipidemia). Bupropion is also used off-label as a first-line treatment in patients with ADHD and comorbid bipolar disorder when used as an adjunct to mood stabilizers. •Indication (Drug B): Naloxone nasal sprays are indicated for the reversal of an opioid overdose or suspected opioid overdose: it is intended for immediate administration as emergency therapy in settings where opioids may be present. Intramuscular, intravenous, and subcutaneous injections are indicated for complete or partial reversal of opioid depression, diagnosis of known or suspected opioid overdose, and as an adjunct therapy in the treatment of septic shock. Sublingual tablets and films are formulated with buprenorphine for the treatment of opioid dependence. Naloxone is also formulated with pentazocine as an oral tablet for severe pain. Intramuscular or subcutaneous naloxone autoinjectors are used for the emergency treatment of people 12 years of age and older where the use of high-potency opioids such as fentanyl analogues as a chemical weapon, is suspected. Naloxone has been used off-label for the treatment of neuraxial opioid-induced pruritus. •Pharmacodynamics (Drug A): Bupropion is chemically unrelated to tricyclic, tetracyclic, selective serotonin re-uptake inhibitors, or other known antidepressant agents. Compared to classical tricyclic antidepressants, Bupropion is a relatively weak inhibitor of the neuronal uptake of norepinephrine and dopamine. In addition, Bupropion does not inhibit monoamine oxidase. Bupropion has been found to be essentially inactive at the serotonin transporter (SERT)(IC50 >10 000 nM), however both bupropion and its primary metabolite hydroxybupropion have been found to block the function of cation-selective serotonin type 3A receptors (5-HT3ARs). Bupropion produces dose-related central nervous system (CNS) stimulant effects in animals, as evidenced by increased locomotor activity, increased rates of responding in various schedule-controlled operant behaviour tasks, and, at high doses, induction of mild stereotyped behaviour. Due to these stimulant effects and selective activity at dopamine and norepinephrine receptors, bupropion has been identified as having an abuse potential. Bupropion has a similar structure to the controlled substance Cathinone, and has been identified as having mild amphetamine-like activity, particularly when inhaled or injected. Bupropion is also known to lower the seizure threshold, making any pre-existing seizure conditions a contraindication to its use. This risk is exacerbated when bupropion is combined with other drugs or substances that lower the seizure threshold, such as cocaine, or in clinical situations that would increase the risk of a seizure such as abrupt alcohol or benzodiazepine withdrawal. As norepinephrine has been shown to have anticonvulsant properties, bupropion's inhibitory effects on NET are thought to contribute to its pro-convulsant activity. Bupropion has been shown to increase blood pressure and pose a risk for exacerbation of unmanaged or pre-existing hypertension, however, clinical trials of bupropion in smokers with CVD have not identified an increased incidence of CV events including stroke or heart attack. In clinical trials, the mean increase in systolic blood pressure associated with the use of bupropion was found to be 1.3 mmHg. •Pharmacodynamics (Drug B): Naloxone is an opioid receptor antagonist indicated in the reversal of opioid overdoses. Naloxone has a shorter duration of action than opioids and multiple doses may be required. The therapeutic window of naloxone is wide, as it has no effect if a patient has not taken opioids. Patients treated with naloxone may experience opioid withdrawal and a person administering naloxone should be aware that reversal of opioid overdoses may not resolve all the symptoms a patient is experiencing if other drugs are involved. •Mechanism of action (Drug A): Bupropion is a norepinephrine/dopamine-reuptake inhibitor (NDRI) that exerts its pharmacological effects by weakly inhibiting the enzymes involved in the uptake of the neurotransmitters norepinephrine and dopamine from the synaptic cleft, therefore prolonging their duration of action within the neuronal synapse and the downstream effects of these neurotransmitters. More specifically, bupropion binds to the norepinephrine transporter (NET) and the dopamine transporter (DAT). Bupropion was originally classified as an "atypical" antidepressant because it does not exert the same effects as the classical antidepressants such as Monoamine Oxidase Inhibitors (MAOIs), Tricyclic Antidepressants (TCAs), or Selective Serotonin Reuptake Inhibitors (SSRIs). While it has comparable effectiveness to typical first-line options for the treatment of depression such as SSRIs, bupropion is a unique option for the treatment of MDD as it lacks any clinically relevant serotonergic effects, typical of other mood medications, or any effects on histamine or adrenaline receptors. Lack of activity at these receptors results in a more tolerable side effect profile; bupropion is less likely to cause sexual side effects, sedation, or weight gain as compared to SSRIs or TCAs, for example. When used as an aid to smoking cessation, bupropion is thought to confer its anti-craving and anti-withdrawal effects by inhibiting dopamine reuptake, which is thought to be involved in the reward pathways associated with nicotine, and through the antagonism of the nicotinic acetylcholinergic receptor (AChR), thereby blunting the effects of nicotine. Furthermore, the stimulatory effects produced by bupropion in the central nervous system are similar to nicotine's effects, making low doses of bupropion a suitable option as a nicotine substitute. When used in combination with naltrexone in the marketed product ContraveⓇ for chronic weight management, the two components are thought to have effects on areas of the brain involved in the regulation of food intake. This includes the hypothalamus, which is involved in appetite regulation, and the mesolimbic dopamine circuit, which is involved in reward pathways. Studies have shown that the combined activity of bupropion and naltrexone increase the firing rate of hypothalamic pro-opiomelanocortin (POMC) neurons and blockade of opioid receptor-mediated POMC auto-inhibition, which are associated with a reduction in food intake and increased energy expenditure. This combination was also found to reduce food intake when injected directly into the ventral tegmental area of the mesolimbic circuit in mice, which is an area associated with the regulation of reward pathways. •Mechanism of action (Drug B): Naloxone is a competitive inhibitor of the µ-opioid receptor. Naloxone antagonizes the action of opioids, reversing their effects. If a patient has not taken opioids, naloxone does not have a significant effect on patients. •Absorption (Drug A): Bupropion is currently available in 3 distinct, but bioequivalent formulations: immediate release (IR), sustained-release (SR), and extended-release (XL). Immediate Release Formulation In humans, following oral administration of bupropion hydrochloride tablets, peak plasma bupropion concentrations are usually achieved within 2 hours. IR formulations provide a short duration of action and are therefore generally dosed three times per day. Sustained Release Formulation In humans, following oral administration of bupropion hydrochloride sustained-release tablets (SR), peak plasma concentration (Cmax) of bupropion is usually achieved within 3 hours. SR formulations provide a 12-hour extended release of medication and are therefore generally dosed twice per day. Extended Release Formulation Following single oral administration of bupropion hydrochloride extended-release tablets (XL) to healthy volunteers, the median time to peak plasma concentrations for bupropion was approximately 5 hours. The presence of food did not affect the peak concentration or area under the curve of bupropion. XL formulations provide a 24-hour extended release of medication and are therefore generally dosed once per day/ In a trial comparing chronic dosing with bupropion hydrochloride extended-release tablets (SR) 150 mg twice daily to bupropion immediate-release formulation 100 mg 3 times daily, the steady state Cmax for bupropion after bupropion hydrochloride sustained-release tablets (SR) administration was approximately 85% of those achieved after bupropion immediate-release formulation administration. Exposure (AUC) to bupropion was equivalent for both formulations. Bioequivalence was also demonstrated for all three major active metabolites (i.e., hydroxybupropion, threohydrobupropion and erythrohydrobupropion) for both Cmax and AUC. Thus, at steady state, bupropion hydrochloride sustained-release tablets (SR) given twice daily, and the immediate-release formulation of bupropion given 3 times daily, are essentially bioequivalent for both bupropion and the 3 quantitatively important metabolites. Furthermore, in a study comparing 14-day dosing with bupropion hydrochloride extended-release tablets (XL), 300 mg once-daily to the immediate-release formulation of bupropion at 100 mg 3 times daily, equivalence was demonstrated for peak plasma concentration and area under the curve for bupropion and the three metabolites (hydroxybupropion, threohydrobupropion, and erythrohydrobupropion). Additionally, in a study comparing 14-day dosing with bupropion hydrochloride extended-release tablets (XL) 300 mg once daily to the sustained-release formulation of bupropion at 150 mg 2 times daily, equivalence was demonstrated for peak plasma concentration and area under the curve for bupropion and the three metabolites. Bupropion hydrochloride extended-release tablets (SR) can be taken with or without food. Bupropion Cmax and AUC were increased by 11% to 35% and 16% to 19%, respectively, when bupropion hydrochloride extended-release tablets (SR) was administered with food to healthy volunteers in three trials. The food effect is not considered clinically significant. Following a single-dose administration of bupropion hydrochloride extended-release tablets (SR) in humans, Cmax of bupropion's metabolite hydroxybupropion occurs approximately 6 hours post-dose and is approximately 10 times the peak level of the parent drug at steady state. The elimination half-life of hydroxybupropion is approximately 20 (±5) hours and its AUC at steady state is about 17 times that of bupropion. The times to peak concentrations for the erythrohydrobupropion and threohydrobupropion metabolites are similar to that of the hydroxybupropion metabolite. However, their elimination half-lives are longer, 33(±10) and 37 (±13) hours, respectively, and steady-state AUCs are 1.5 and 7 times that of bupropion, respectively. •Absorption (Drug B): An intranasal dose of naloxone is 42-47% bioavailable. An 8 mg dose of nasal naloxone reaches a C max of 12.3-12.8 ng/mL, with a T max of 0.25 hours, and an AUC of 16.7-19.0 h*ng/mL. A 0.4 mg intramuscular dose reaches a C max of 0.876-0.910 ng/mL, with a T max of 0.25 hours, and an AUC of 1.94-1.95 h*ng/mL. A 2 mg intravenous dose reaches a C max of 26.2 ng/mL with an AUC of 12.8 h*ng/mL. •Volume of distribution (Drug A): No volume of distribution available •Volume of distribution (Drug B): The volume of distribution of naloxone is 200 L. Naloxone distributes into tissues rapidly. It can also cross the placenta and blood-brain barrier. •Protein binding (Drug A): In vitro tests show that bupropion is 84% bound to human plasma proteins at concentrations up to 200 mcg per mL. The extent of protein binding of the hydroxybupropion metabolite is similar to that for bupropion, whereas the extent of protein binding of the threohydrobupropion metabolite is about half that seen with bupropion. •Protein binding (Drug B): Naloxone is approximately 45% bound to albumin, but there is significant binding to other proteins. •Metabolism (Drug A): Bupropion is extensively metabolized in humans. Three metabolites are active: hydroxybupropion, which is formed via hydroxylation of the tert-butyl group of bupropion, and the amino-alcohol isomers, threohydrobupropion and erythrohydrobupropion, which are formed via reduction of the carbonyl group. In vitro findings suggest that CYP2B6 is the principal isoenzyme involved in the formation of hydroxybupropion, while cytochrome P450 enzymes are not involved in the formation of threohydrobupropion. Hydroxybupropion has been shown to have the same affinity as bupropion for the norepinephrine transporter (NET) but approximately 50% of its antidepressant activity despite reaching concentrations of ~10-fold higher than that of the parent drug. Oxidation of the bupropion side chain results in the formation of a glycine conjugate of meta-chlorobenzoic acid, which is then excreted as the major urinary metabolite. The potency and toxicity of the metabolites relative to bupropion have not been fully characterized. However, it has been demonstrated in an antidepressant screening test in mice that hydroxybupropion is one-half as potent as bupropion, while threohydrobupropion and erythrohydrobupropion are 5-fold less potent than bupropion. This may be of clinical importance because the plasma concentrations of the metabolites are as high as or higher than those of bupropion. Bupropion and its metabolites exhibit linear kinetics following chronic administration of 300 to 450 mg per day. •Metabolism (Drug B): Naloxone primarily undergoes glucuronidation to form naloxone-3-glucuronide. Naloxone is also N-dealkylated to noroxymorphone or undergoes 6-keto reduction to naloxol. •Route of elimination (Drug A): Bupropion is extensively metabolized in humans. Oxidation of the bupropion side chain results in the formation of a glycine conjugate of metachlorobenzoic acid, which is then excreted as the major urinary metabolite. Following oral administration of 200 mg of 14C-bupropion in humans, 87% and 10% of the radioactive dose were recovered in the urine and feces, respectively. However, the fraction of the oral dose of bupropion excreted unchanged was only 0.5%, a finding consistent with the extensive metabolism of bupropion. •Route of elimination (Drug B): After oral or intravenous administration, naloxone is 25-40% eliminated in the urine within 6 hours, 50% in 24 hours, and 60-70% in 72 hours. The metabolites naloxone-3-glucuronide, noroxymorphone, and naloxol are all detected in the urine. •Half-life (Drug A): 24 hours •Half-life (Drug B): The mean half life of naloxone hydrochloride is 1.8-2.7 hours intranasally, 1.4 hours intramuscularly, and 1.2 hours intravenously. In neonates, the mean half life is 3.1 ± 0.5 hours. •Clearance (Drug A): No clearance available •Clearance (Drug B): The clearance of naloxone is 2500 L/day. •Toxicity (Drug A): Symptoms of overdose include seizures, hallucinations, loss of consciousness, tachycardia, and cardiac arrest. •Toxicity (Drug B): If a patient has not taken opioids, naloxone does not have a significant effect on patients. The oral LD 50 in mice and rats is >1 g/kg. The intraperitoneal LD 50 is 80 mg/kg in mice and 239 mg/kg in rats. The subcutaneous LD 50 is 286 mg/kg in mice and 500 mg/kg in rats. •Brand Names (Drug A): Aplenzin, Auvelity, Budeprion, Contrave, Forfivo, Wellbutrin, Zyban •Brand Names (Drug B): Kloxxado, Narcan, Suboxone, Targin, Targiniq, Zimhi, Zubsolv •Synonyms (Drug A): No synonyms listed •Synonyms (Drug B): Nalossone Naloxona Naloxone Naloxonum •Summary (Drug A): Bupropion is a norepinephrine and dopamine reuptake inhibitor used in the treatment of major depressive disorder (MDD), seasonal affective disorder (SAD), and as an aid to smoking cessation. •Summary (Drug B): Naloxone is an opioid receptor antagonist used to rapidly reverse an opioid overdose. Also included in some drug formulations as an abuse deterrent to prevent injection. Output: The renal excretion of drugs is the overall result of a combination of kidney processes that include glomerular filtration, passive diffusion, tubular secretion, and tubular reabsorption. Since two of these mechanisms - tubular secretion and reabsorption - are saturable processes , they are consequently susceptible to competition between multiple substrates excreted by the kidneys. If two or more medications that are mainly renally excreted are co-administered, they may compete for renal elimination; there is a large likelihood that one agent may "out-compete" or saturate the renal excretion mechanisms before the other concomitantly administered agent(s) are excreted. As a result, the elimination of these other concurrently administered agents may be inhibited or otherwise delayed, which could lead to increases in their serum concentrations and the risk, incidence, and/or severity of adverse effects associated with the exposure to such drugs. The severity of the interaction is minor.

Does Bupropion and Naproxen interact?

•Drug A: Bupropion •Drug B: Naproxen •Severity: MINOR •Description: Naproxen may decrease the excretion rate of Bupropion which could result in a higher serum level. •Extended Description: The subject drug is a nephrotoxic agent that may potentially impair renal function and decrease the excretion of drugs that mainly undergo renal excretion as the principal mode of clearance, such as the affected drug. Attenuated renal excretion of the affected drug may increase drug concentrations, leading to an elevated risk for drug-related adverse effects. •Indication (Drug A): Bupropion is indicated for the treatment of major depressive disorder (MDD), seasonal affective disorder (SAD), and as an aid to smoking cessation. When used in combination with naltrexone as the marketed product ContraveⓇ, bupropion is indicated as an adjunct to a reduced-calorie diet and increased physical activity for chronic weight management in adults with an initial body mass index (BMI) of: 30 kg/m^2 or greater (obese) or 27 kg/m^2 or greater (overweight) in the presence of at least one weight-related comorbid condition (e.g., hypertension, type 2 diabetes mellitus, or dyslipidemia). Bupropion is also used off-label as a first-line treatment in patients with ADHD and comorbid bipolar disorder when used as an adjunct to mood stabilizers. •Indication (Drug B): Naproxen is indicated for the management of rheumatoid arthritis, osteoarthritis, ankylosing spondylitis, polyarticular juvenile idiopathic arthritis, tendinitis, bursitis, acute gout, primary dysmenorrhea, and for the relief of mild to moderate pain. Further, it is first-line therapy for osteoarthritis, acute gouty arthritis, dysmenorrhea, and musculoskeletal inflammation and pain. •Pharmacodynamics (Drug A): Bupropion is chemically unrelated to tricyclic, tetracyclic, selective serotonin re-uptake inhibitors, or other known antidepressant agents. Compared to classical tricyclic antidepressants, Bupropion is a relatively weak inhibitor of the neuronal uptake of norepinephrine and dopamine. In addition, Bupropion does not inhibit monoamine oxidase. Bupropion has been found to be essentially inactive at the serotonin transporter (SERT)(IC50 >10 000 nM), however both bupropion and its primary metabolite hydroxybupropion have been found to block the function of cation-selective serotonin type 3A receptors (5-HT3ARs). Bupropion produces dose-related central nervous system (CNS) stimulant effects in animals, as evidenced by increased locomotor activity, increased rates of responding in various schedule-controlled operant behaviour tasks, and, at high doses, induction of mild stereotyped behaviour. Due to these stimulant effects and selective activity at dopamine and norepinephrine receptors, bupropion has been identified as having an abuse potential. Bupropion has a similar structure to the controlled substance Cathinone, and has been identified as having mild amphetamine-like activity, particularly when inhaled or injected. Bupropion is also known to lower the seizure threshold, making any pre-existing seizure conditions a contraindication to its use. This risk is exacerbated when bupropion is combined with other drugs or substances that lower the seizure threshold, such as cocaine, or in clinical situations that would increase the risk of a seizure such as abrupt alcohol or benzodiazepine withdrawal. As norepinephrine has been shown to have anticonvulsant properties, bupropion's inhibitory effects on NET are thought to contribute to its pro-convulsant activity. Bupropion has been shown to increase blood pressure and pose a risk for exacerbation of unmanaged or pre-existing hypertension, however, clinical trials of bupropion in smokers with CVD have not identified an increased incidence of CV events including stroke or heart attack. In clinical trials, the mean increase in systolic blood pressure associated with the use of bupropion was found to be 1.3 mmHg. •Pharmacodynamics (Drug B): Naproxen is an established non-selective NSAID and is useful as an analgesic, anti-inflammatory and antipyretic. Similar to other NSAIDs, the pharmacological activity of naproxen can be attributed to the inhibition of cyclo-oxygenase, which in turn reduces prostaglandin synthesis in various tissues and fluids including the synovial fluid, gastric mucosa, and the blood. Although naproxen is an effective analgesic, it can have unintended deleterious effects in the patient. For instance, naproxen can adversely affect blood pressure control. A study found that use of naproxen induced an increase in blood pressure, although the increase was not as significant as that found with ibuprofen use. Further, studies have found that the risk of upper gastrointestinal bleeding is on average four-fold higher for individuals taking NSAIDs. Other factors that increase the risk of upper gastrointestinal bleeding include concurrent use of corticosteroids or anticoagulants, and a history of gastrointestinal ulcers. •Mechanism of action (Drug A): Bupropion is a norepinephrine/dopamine-reuptake inhibitor (NDRI) that exerts its pharmacological effects by weakly inhibiting the enzymes involved in the uptake of the neurotransmitters norepinephrine and dopamine from the synaptic cleft, therefore prolonging their duration of action within the neuronal synapse and the downstream effects of these neurotransmitters. More specifically, bupropion binds to the norepinephrine transporter (NET) and the dopamine transporter (DAT). Bupropion was originally classified as an "atypical" antidepressant because it does not exert the same effects as the classical antidepressants such as Monoamine Oxidase Inhibitors (MAOIs), Tricyclic Antidepressants (TCAs), or Selective Serotonin Reuptake Inhibitors (SSRIs). While it has comparable effectiveness to typical first-line options for the treatment of depression such as SSRIs, bupropion is a unique option for the treatment of MDD as it lacks any clinically relevant serotonergic effects, typical of other mood medications, or any effects on histamine or adrenaline receptors. Lack of activity at these receptors results in a more tolerable side effect profile; bupropion is less likely to cause sexual side effects, sedation, or weight gain as compared to SSRIs or TCAs, for example. When used as an aid to smoking cessation, bupropion is thought to confer its anti-craving and anti-withdrawal effects by inhibiting dopamine reuptake, which is thought to be involved in the reward pathways associated with nicotine, and through the antagonism of the nicotinic acetylcholinergic receptor (AChR), thereby blunting the effects of nicotine. Furthermore, the stimulatory effects produced by bupropion in the central nervous system are similar to nicotine's effects, making low doses of bupropion a suitable option as a nicotine substitute. When used in combination with naltrexone in the marketed product ContraveⓇ for chronic weight management, the two components are thought to have effects on areas of the brain involved in the regulation of food intake. This includes the hypothalamus, which is involved in appetite regulation, and the mesolimbic dopamine circuit, which is involved in reward pathways. Studies have shown that the combined activity of bupropion and naltrexone increase the firing rate of hypothalamic pro-opiomelanocortin (POMC) neurons and blockade of opioid receptor-mediated POMC auto-inhibition, which are associated with a reduction in food intake and increased energy expenditure. This combination was also found to reduce food intake when injected directly into the ventral tegmental area of the mesolimbic circuit in mice, which is an area associated with the regulation of reward pathways. •Mechanism of action (Drug B): As with other non-selective NSAIDs, naproxen exerts it's clinical effects by blocking COX-1 and COX-2 enzymes leading to decreased prostaglandin synthesis. Although both enzymes contribute to prostaglandin production, they have unique functional differences. The COX-1 enzymes is constitutively active and can be found in normal tissues such as the stomach lining, while the COX-2 enzyme is inducible and produces prostaglandins that mediate pain, fever and inflammation. The COX-2 enzyme mediates the desired antipyretic, analgesic and anti-inflammatory properties offered by Naproxen, while undesired adverse effects such as gastrointestinal upset and renal toxicities are linked to the COX-1 enzyme. •Absorption (Drug A): Bupropion is currently available in 3 distinct, but bioequivalent formulations: immediate release (IR), sustained-release (SR), and extended-release (XL). Immediate Release Formulation In humans, following oral administration of bupropion hydrochloride tablets, peak plasma bupropion concentrations are usually achieved within 2 hours. IR formulations provide a short duration of action and are therefore generally dosed three times per day. Sustained Release Formulation In humans, following oral administration of bupropion hydrochloride sustained-release tablets (SR), peak plasma concentration (Cmax) of bupropion is usually achieved within 3 hours. SR formulations provide a 12-hour extended release of medication and are therefore generally dosed twice per day. Extended Release Formulation Following single oral administration of bupropion hydrochloride extended-release tablets (XL) to healthy volunteers, the median time to peak plasma concentrations for bupropion was approximately 5 hours. The presence of food did not affect the peak concentration or area under the curve of bupropion. XL formulations provide a 24-hour extended release of medication and are therefore generally dosed once per day/ In a trial comparing chronic dosing with bupropion hydrochloride extended-release tablets (SR) 150 mg twice daily to bupropion immediate-release formulation 100 mg 3 times daily, the steady state Cmax for bupropion after bupropion hydrochloride sustained-release tablets (SR) administration was approximately 85% of those achieved after bupropion immediate-release formulation administration. Exposure (AUC) to bupropion was equivalent for both formulations. Bioequivalence was also demonstrated for all three major active metabolites (i.e., hydroxybupropion, threohydrobupropion and erythrohydrobupropion) for both Cmax and AUC. Thus, at steady state, bupropion hydrochloride sustained-release tablets (SR) given twice daily, and the immediate-release formulation of bupropion given 3 times daily, are essentially bioequivalent for both bupropion and the 3 quantitatively important metabolites. Furthermore, in a study comparing 14-day dosing with bupropion hydrochloride extended-release tablets (XL), 300 mg once-daily to the immediate-release formulation of bupropion at 100 mg 3 times daily, equivalence was demonstrated for peak plasma concentration and area under the curve for bupropion and the three metabolites (hydroxybupropion, threohydrobupropion, and erythrohydrobupropion). Additionally, in a study comparing 14-day dosing with bupropion hydrochloride extended-release tablets (XL) 300 mg once daily to the sustained-release formulation of bupropion at 150 mg 2 times daily, equivalence was demonstrated for peak plasma concentration and area under the curve for bupropion and the three metabolites. Bupropion hydrochloride extended-release tablets (SR) can be taken with or without food. Bupropion Cmax and AUC were increased by 11% to 35% and 16% to 19%, respectively, when bupropion hydrochloride extended-release tablets (SR) was administered with food to healthy volunteers in three trials. The food effect is not considered clinically significant. Following a single-dose administration of bupropion hydrochloride extended-release tablets (SR) in humans, Cmax of bupropion's metabolite hydroxybupropion occurs approximately 6 hours post-dose and is approximately 10 times the peak level of the parent drug at steady state. The elimination half-life of hydroxybupropion is approximately 20 (±5) hours and its AUC at steady state is about 17 times that of bupropion. The times to peak concentrations for the erythrohydrobupropion and threohydrobupropion metabolites are similar to that of the hydroxybupropion metabolite. However, their elimination half-lives are longer, 33(±10) and 37 (±13) hours, respectively, and steady-state AUCs are 1.5 and 7 times that of bupropion, respectively. •Absorption (Drug B): Naproxen is available as a free acid and sodium salt. At comparable doses, (naproxen 500 mg = naproxen sodium 550 mg) they differ slightly in their rates of absorption, but otherwise they are therapeutically and pharmacologically equivalent. Naproxen sodium achieves a peak plasma concentration after 1 hour, while peak plasma concentration is observed after 2 hours with naproxen (free acid). There are no differences between the 2 forms in the post-absorption phase pharmacokinetics. The difference in initial absorption should be considered when treating acute pain, since naproxen sodium may offer a quicker onset of action. The mean Cmax for the various formulations (immediate release, enteric coated, controlled release etc.) of naproxen are comparable and range from 94 mcg/mL to 97.4 mcg/mL. In one pharmacokinetic study, the mean Tmax of naproxen 500 mg (immediate release) given every 12 hours over 5 days was 3 hours, compared to a mean Tmax of 5 hours for Naprelan 1000 mg (controlled release) given every 24 hours over 5 days. In this same study, the AUC 0-24hr was 1446mcgxhr/mL for naproxen immediate release and 1448 mcgxhr/mL for the controlled release formulation. A separate study comparing the pharmacokinetics of Naprosyn tablets and EC-Naprosyn observed the following values: Tmax and AUC 0-12hrs of EC-Naprosyn were 4 hours and 845 mcgxhr/mL respectively, and Tmax and AUC 0-12hrs values of Naprosyn were 1.9 hours and 767 mcgxhr/mL respectively. When given in combination with sumatriptan the Cmax of naproxen is roughly 36% lower compared to naproxen sodium 550 mg tablets, and the median Tmax is 5 hours. Based on the AUC and Cmax of naproxen, Vimovo (naproxen/esomeprazole combination product) and enteric-coated naproxen may be considered bioequivalent. Overall, naproxen is rapidly and completely absorbed when administered orally and rectally. Food may contribute to a delay in the absorption of orally administered naproxen, but will not affect the extent of absorption. •Volume of distribution (Drug A): No volume of distribution available •Volume of distribution (Drug B): Naproxen has a volume of distribution of 0.16 L/kg. •Protein binding (Drug A): In vitro tests show that bupropion is 84% bound to human plasma proteins at concentrations up to 200 mcg per mL. The extent of protein binding of the hydroxybupropion metabolite is similar to that for bupropion, whereas the extent of protein binding of the threohydrobupropion metabolite is about half that seen with bupropion. •Protein binding (Drug B): Naproxen is highly protein bound with >99% of the drug bound to albumin at therapeutic levels. •Metabolism (Drug A): Bupropion is extensively metabolized in humans. Three metabolites are active: hydroxybupropion, which is formed via hydroxylation of the tert-butyl group of bupropion, and the amino-alcohol isomers, threohydrobupropion and erythrohydrobupropion, which are formed via reduction of the carbonyl group. In vitro findings suggest that CYP2B6 is the principal isoenzyme involved in the formation of hydroxybupropion, while cytochrome P450 enzymes are not involved in the formation of threohydrobupropion. Hydroxybupropion has been shown to have the same affinity as bupropion for the norepinephrine transporter (NET) but approximately 50% of its antidepressant activity despite reaching concentrations of ~10-fold higher than that of the parent drug. Oxidation of the bupropion side chain results in the formation of a glycine conjugate of meta-chlorobenzoic acid, which is then excreted as the major urinary metabolite. The potency and toxicity of the metabolites relative to bupropion have not been fully characterized. However, it has been demonstrated in an antidepressant screening test in mice that hydroxybupropion is one-half as potent as bupropion, while threohydrobupropion and erythrohydrobupropion are 5-fold less potent than bupropion. This may be of clinical importance because the plasma concentrations of the metabolites are as high as or higher than those of bupropion. Bupropion and its metabolites exhibit linear kinetics following chronic administration of 300 to 450 mg per day. •Metabolism (Drug B): Naproxen is heavily metabolized in the liver and undergoes both Phase I and Phase II metabolism. The first step involves demethylation of naproxen via CYP 1A2, 2C8, and 2C9. Both naproxen and desmethylnaproxen proceed to Phase II metabolism; however, desmethylnaproxen can form both acyl and phenolic glucoronide products, while naproxen only produces the acyl glucuronide. The acyl glucuronidation process involves UGT 1A1, 1A3, 1A6, 1A7, 1A9, 1A10 and 2B7, while phenolic glucuronidation is catalyzed by UGT 1A1, 1A7,1A9, and 1A10. Desmethylnaproxen also undergoes sulphation which is mediated by SULT 1A1, 1B1 and 1E1. •Route of elimination (Drug A): Bupropion is extensively metabolized in humans. Oxidation of the bupropion side chain results in the formation of a glycine conjugate of metachlorobenzoic acid, which is then excreted as the major urinary metabolite. Following oral administration of 200 mg of 14C-bupropion in humans, 87% and 10% of the radioactive dose were recovered in the urine and feces, respectively. However, the fraction of the oral dose of bupropion excreted unchanged was only 0.5%, a finding consistent with the extensive metabolism of bupropion. •Route of elimination (Drug B): After oral administration, about 95% of naproxen and it's metabolites can be recovered in the urine with 66-92% recovered as conjugated metabolite and less than 1% recovered as naproxen or desmethylnaproxen. Less than 5% of naproxen is excreted in the feces. •Half-life (Drug A): 24 hours •Half-life (Drug B): The elimination half-life of naproxen is reported to be 12-17 hours. •Clearance (Drug A): No clearance available •Clearance (Drug B): Naproxen is cleared at a rate of 0.13 mL/min/kg. •Toxicity (Drug A): Symptoms of overdose include seizures, hallucinations, loss of consciousness, tachycardia, and cardiac arrest. •Toxicity (Drug B): Although the over-the-counter (OTC) availability of naproxen provides convenience to patients, it also increases the likelihood of overdose. Thankfully, the extent of overdose is typically mild with adverse effects normally limited to drowsiness, lethargy, epigastric pain, nausea and vomiting. Although there is no antidote for naproxen overdose, symptoms will typically subside with appropriate supportive care. Naproxen is classified as Category B during the first 2 trimesters of pregnancy, and as Category D during the third trimester. Naproxen is contraindicated in the 3rd trimester since it increases the risk of premature closure of the fetal ductus arteriosus and should be avoided in pregnant women starting at 30 weeks gestation. •Brand Names (Drug A): Aplenzin, Auvelity, Budeprion, Contrave, Forfivo, Wellbutrin, Zyban •Brand Names (Drug B): Aleve, Aleve PM, Aleve-D, Anaprox, Naprelan, Naprosyn, Sallus, Sudafed Sinus & Pain, Treximet, Vimovo •Synonyms (Drug A): No synonyms listed •Synonyms (Drug B): (S)-Naproxen Naprolag Naproxen Naproxène Naproxeno Naproxenum •Summary (Drug A): Bupropion is a norepinephrine and dopamine reuptake inhibitor used in the treatment of major depressive disorder (MDD), seasonal affective disorder (SAD), and as an aid to smoking cessation. •Summary (Drug B): Naproxen is an NSAID used to treat rheumatoid arthritis, osteoarthritis, ankylosing spondylitis, polyarticular juvenile idiopathic arthritis, tendinitis, bursitis, acute gout, primary dysmenorrhea, and mild to moderate pain.

The subject drug is a nephrotoxic agent that may potentially impair renal function and decrease the excretion of drugs that mainly undergo renal excretion as the principal mode of clearance, such as the affected drug. Attenuated renal excretion of the affected drug may increase drug concentrations, leading to an elevated risk for drug-related adverse effects. The severity of the interaction is minor.

Question: Does Bupropion and Naproxen interact? Information: •Drug A: Bupropion •Drug B: Naproxen •Severity: MINOR •Description: Naproxen may decrease the excretion rate of Bupropion which could result in a higher serum level. •Extended Description: The subject drug is a nephrotoxic agent that may potentially impair renal function and decrease the excretion of drugs that mainly undergo renal excretion as the principal mode of clearance, such as the affected drug. Attenuated renal excretion of the affected drug may increase drug concentrations, leading to an elevated risk for drug-related adverse effects. •Indication (Drug A): Bupropion is indicated for the treatment of major depressive disorder (MDD), seasonal affective disorder (SAD), and as an aid to smoking cessation. When used in combination with naltrexone as the marketed product ContraveⓇ, bupropion is indicated as an adjunct to a reduced-calorie diet and increased physical activity for chronic weight management in adults with an initial body mass index (BMI) of: 30 kg/m^2 or greater (obese) or 27 kg/m^2 or greater (overweight) in the presence of at least one weight-related comorbid condition (e.g., hypertension, type 2 diabetes mellitus, or dyslipidemia). Bupropion is also used off-label as a first-line treatment in patients with ADHD and comorbid bipolar disorder when used as an adjunct to mood stabilizers. •Indication (Drug B): Naproxen is indicated for the management of rheumatoid arthritis, osteoarthritis, ankylosing spondylitis, polyarticular juvenile idiopathic arthritis, tendinitis, bursitis, acute gout, primary dysmenorrhea, and for the relief of mild to moderate pain. Further, it is first-line therapy for osteoarthritis, acute gouty arthritis, dysmenorrhea, and musculoskeletal inflammation and pain. •Pharmacodynamics (Drug A): Bupropion is chemically unrelated to tricyclic, tetracyclic, selective serotonin re-uptake inhibitors, or other known antidepressant agents. Compared to classical tricyclic antidepressants, Bupropion is a relatively weak inhibitor of the neuronal uptake of norepinephrine and dopamine. In addition, Bupropion does not inhibit monoamine oxidase. Bupropion has been found to be essentially inactive at the serotonin transporter (SERT)(IC50 >10 000 nM), however both bupropion and its primary metabolite hydroxybupropion have been found to block the function of cation-selective serotonin type 3A receptors (5-HT3ARs). Bupropion produces dose-related central nervous system (CNS) stimulant effects in animals, as evidenced by increased locomotor activity, increased rates of responding in various schedule-controlled operant behaviour tasks, and, at high doses, induction of mild stereotyped behaviour. Due to these stimulant effects and selective activity at dopamine and norepinephrine receptors, bupropion has been identified as having an abuse potential. Bupropion has a similar structure to the controlled substance Cathinone, and has been identified as having mild amphetamine-like activity, particularly when inhaled or injected. Bupropion is also known to lower the seizure threshold, making any pre-existing seizure conditions a contraindication to its use. This risk is exacerbated when bupropion is combined with other drugs or substances that lower the seizure threshold, such as cocaine, or in clinical situations that would increase the risk of a seizure such as abrupt alcohol or benzodiazepine withdrawal. As norepinephrine has been shown to have anticonvulsant properties, bupropion's inhibitory effects on NET are thought to contribute to its pro-convulsant activity. Bupropion has been shown to increase blood pressure and pose a risk for exacerbation of unmanaged or pre-existing hypertension, however, clinical trials of bupropion in smokers with CVD have not identified an increased incidence of CV events including stroke or heart attack. In clinical trials, the mean increase in systolic blood pressure associated with the use of bupropion was found to be 1.3 mmHg. •Pharmacodynamics (Drug B): Naproxen is an established non-selective NSAID and is useful as an analgesic, anti-inflammatory and antipyretic. Similar to other NSAIDs, the pharmacological activity of naproxen can be attributed to the inhibition of cyclo-oxygenase, which in turn reduces prostaglandin synthesis in various tissues and fluids including the synovial fluid, gastric mucosa, and the blood. Although naproxen is an effective analgesic, it can have unintended deleterious effects in the patient. For instance, naproxen can adversely affect blood pressure control. A study found that use of naproxen induced an increase in blood pressure, although the increase was not as significant as that found with ibuprofen use. Further, studies have found that the risk of upper gastrointestinal bleeding is on average four-fold higher for individuals taking NSAIDs. Other factors that increase the risk of upper gastrointestinal bleeding include concurrent use of corticosteroids or anticoagulants, and a history of gastrointestinal ulcers. •Mechanism of action (Drug A): Bupropion is a norepinephrine/dopamine-reuptake inhibitor (NDRI) that exerts its pharmacological effects by weakly inhibiting the enzymes involved in the uptake of the neurotransmitters norepinephrine and dopamine from the synaptic cleft, therefore prolonging their duration of action within the neuronal synapse and the downstream effects of these neurotransmitters. More specifically, bupropion binds to the norepinephrine transporter (NET) and the dopamine transporter (DAT). Bupropion was originally classified as an "atypical" antidepressant because it does not exert the same effects as the classical antidepressants such as Monoamine Oxidase Inhibitors (MAOIs), Tricyclic Antidepressants (TCAs), or Selective Serotonin Reuptake Inhibitors (SSRIs). While it has comparable effectiveness to typical first-line options for the treatment of depression such as SSRIs, bupropion is a unique option for the treatment of MDD as it lacks any clinically relevant serotonergic effects, typical of other mood medications, or any effects on histamine or adrenaline receptors. Lack of activity at these receptors results in a more tolerable side effect profile; bupropion is less likely to cause sexual side effects, sedation, or weight gain as compared to SSRIs or TCAs, for example. When used as an aid to smoking cessation, bupropion is thought to confer its anti-craving and anti-withdrawal effects by inhibiting dopamine reuptake, which is thought to be involved in the reward pathways associated with nicotine, and through the antagonism of the nicotinic acetylcholinergic receptor (AChR), thereby blunting the effects of nicotine. Furthermore, the stimulatory effects produced by bupropion in the central nervous system are similar to nicotine's effects, making low doses of bupropion a suitable option as a nicotine substitute. When used in combination with naltrexone in the marketed product ContraveⓇ for chronic weight management, the two components are thought to have effects on areas of the brain involved in the regulation of food intake. This includes the hypothalamus, which is involved in appetite regulation, and the mesolimbic dopamine circuit, which is involved in reward pathways. Studies have shown that the combined activity of bupropion and naltrexone increase the firing rate of hypothalamic pro-opiomelanocortin (POMC) neurons and blockade of opioid receptor-mediated POMC auto-inhibition, which are associated with a reduction in food intake and increased energy expenditure. This combination was also found to reduce food intake when injected directly into the ventral tegmental area of the mesolimbic circuit in mice, which is an area associated with the regulation of reward pathways. •Mechanism of action (Drug B): As with other non-selective NSAIDs, naproxen exerts it's clinical effects by blocking COX-1 and COX-2 enzymes leading to decreased prostaglandin synthesis. Although both enzymes contribute to prostaglandin production, they have unique functional differences. The COX-1 enzymes is constitutively active and can be found in normal tissues such as the stomach lining, while the COX-2 enzyme is inducible and produces prostaglandins that mediate pain, fever and inflammation. The COX-2 enzyme mediates the desired antipyretic, analgesic and anti-inflammatory properties offered by Naproxen, while undesired adverse effects such as gastrointestinal upset and renal toxicities are linked to the COX-1 enzyme. •Absorption (Drug A): Bupropion is currently available in 3 distinct, but bioequivalent formulations: immediate release (IR), sustained-release (SR), and extended-release (XL). Immediate Release Formulation In humans, following oral administration of bupropion hydrochloride tablets, peak plasma bupropion concentrations are usually achieved within 2 hours. IR formulations provide a short duration of action and are therefore generally dosed three times per day. Sustained Release Formulation In humans, following oral administration of bupropion hydrochloride sustained-release tablets (SR), peak plasma concentration (Cmax) of bupropion is usually achieved within 3 hours. SR formulations provide a 12-hour extended release of medication and are therefore generally dosed twice per day. Extended Release Formulation Following single oral administration of bupropion hydrochloride extended-release tablets (XL) to healthy volunteers, the median time to peak plasma concentrations for bupropion was approximately 5 hours. The presence of food did not affect the peak concentration or area under the curve of bupropion. XL formulations provide a 24-hour extended release of medication and are therefore generally dosed once per day/ In a trial comparing chronic dosing with bupropion hydrochloride extended-release tablets (SR) 150 mg twice daily to bupropion immediate-release formulation 100 mg 3 times daily, the steady state Cmax for bupropion after bupropion hydrochloride sustained-release tablets (SR) administration was approximately 85% of those achieved after bupropion immediate-release formulation administration. Exposure (AUC) to bupropion was equivalent for both formulations. Bioequivalence was also demonstrated for all three major active metabolites (i.e., hydroxybupropion, threohydrobupropion and erythrohydrobupropion) for both Cmax and AUC. Thus, at steady state, bupropion hydrochloride sustained-release tablets (SR) given twice daily, and the immediate-release formulation of bupropion given 3 times daily, are essentially bioequivalent for both bupropion and the 3 quantitatively important metabolites. Furthermore, in a study comparing 14-day dosing with bupropion hydrochloride extended-release tablets (XL), 300 mg once-daily to the immediate-release formulation of bupropion at 100 mg 3 times daily, equivalence was demonstrated for peak plasma concentration and area under the curve for bupropion and the three metabolites (hydroxybupropion, threohydrobupropion, and erythrohydrobupropion). Additionally, in a study comparing 14-day dosing with bupropion hydrochloride extended-release tablets (XL) 300 mg once daily to the sustained-release formulation of bupropion at 150 mg 2 times daily, equivalence was demonstrated for peak plasma concentration and area under the curve for bupropion and the three metabolites. Bupropion hydrochloride extended-release tablets (SR) can be taken with or without food. Bupropion Cmax and AUC were increased by 11% to 35% and 16% to 19%, respectively, when bupropion hydrochloride extended-release tablets (SR) was administered with food to healthy volunteers in three trials. The food effect is not considered clinically significant. Following a single-dose administration of bupropion hydrochloride extended-release tablets (SR) in humans, Cmax of bupropion's metabolite hydroxybupropion occurs approximately 6 hours post-dose and is approximately 10 times the peak level of the parent drug at steady state. The elimination half-life of hydroxybupropion is approximately 20 (±5) hours and its AUC at steady state is about 17 times that of bupropion. The times to peak concentrations for the erythrohydrobupropion and threohydrobupropion metabolites are similar to that of the hydroxybupropion metabolite. However, their elimination half-lives are longer, 33(±10) and 37 (±13) hours, respectively, and steady-state AUCs are 1.5 and 7 times that of bupropion, respectively. •Absorption (Drug B): Naproxen is available as a free acid and sodium salt. At comparable doses, (naproxen 500 mg = naproxen sodium 550 mg) they differ slightly in their rates of absorption, but otherwise they are therapeutically and pharmacologically equivalent. Naproxen sodium achieves a peak plasma concentration after 1 hour, while peak plasma concentration is observed after 2 hours with naproxen (free acid). There are no differences between the 2 forms in the post-absorption phase pharmacokinetics. The difference in initial absorption should be considered when treating acute pain, since naproxen sodium may offer a quicker onset of action. The mean Cmax for the various formulations (immediate release, enteric coated, controlled release etc.) of naproxen are comparable and range from 94 mcg/mL to 97.4 mcg/mL. In one pharmacokinetic study, the mean Tmax of naproxen 500 mg (immediate release) given every 12 hours over 5 days was 3 hours, compared to a mean Tmax of 5 hours for Naprelan 1000 mg (controlled release) given every 24 hours over 5 days. In this same study, the AUC 0-24hr was 1446mcgxhr/mL for naproxen immediate release and 1448 mcgxhr/mL for the controlled release formulation. A separate study comparing the pharmacokinetics of Naprosyn tablets and EC-Naprosyn observed the following values: Tmax and AUC 0-12hrs of EC-Naprosyn were 4 hours and 845 mcgxhr/mL respectively, and Tmax and AUC 0-12hrs values of Naprosyn were 1.9 hours and 767 mcgxhr/mL respectively. When given in combination with sumatriptan the Cmax of naproxen is roughly 36% lower compared to naproxen sodium 550 mg tablets, and the median Tmax is 5 hours. Based on the AUC and Cmax of naproxen, Vimovo (naproxen/esomeprazole combination product) and enteric-coated naproxen may be considered bioequivalent. Overall, naproxen is rapidly and completely absorbed when administered orally and rectally. Food may contribute to a delay in the absorption of orally administered naproxen, but will not affect the extent of absorption. •Volume of distribution (Drug A): No volume of distribution available •Volume of distribution (Drug B): Naproxen has a volume of distribution of 0.16 L/kg. •Protein binding (Drug A): In vitro tests show that bupropion is 84% bound to human plasma proteins at concentrations up to 200 mcg per mL. The extent of protein binding of the hydroxybupropion metabolite is similar to that for bupropion, whereas the extent of protein binding of the threohydrobupropion metabolite is about half that seen with bupropion. •Protein binding (Drug B): Naproxen is highly protein bound with >99% of the drug bound to albumin at therapeutic levels. •Metabolism (Drug A): Bupropion is extensively metabolized in humans. Three metabolites are active: hydroxybupropion, which is formed via hydroxylation of the tert-butyl group of bupropion, and the amino-alcohol isomers, threohydrobupropion and erythrohydrobupropion, which are formed via reduction of the carbonyl group. In vitro findings suggest that CYP2B6 is the principal isoenzyme involved in the formation of hydroxybupropion, while cytochrome P450 enzymes are not involved in the formation of threohydrobupropion. Hydroxybupropion has been shown to have the same affinity as bupropion for the norepinephrine transporter (NET) but approximately 50% of its antidepressant activity despite reaching concentrations of ~10-fold higher than that of the parent drug. Oxidation of the bupropion side chain results in the formation of a glycine conjugate of meta-chlorobenzoic acid, which is then excreted as the major urinary metabolite. The potency and toxicity of the metabolites relative to bupropion have not been fully characterized. However, it has been demonstrated in an antidepressant screening test in mice that hydroxybupropion is one-half as potent as bupropion, while threohydrobupropion and erythrohydrobupropion are 5-fold less potent than bupropion. This may be of clinical importance because the plasma concentrations of the metabolites are as high as or higher than those of bupropion. Bupropion and its metabolites exhibit linear kinetics following chronic administration of 300 to 450 mg per day. •Metabolism (Drug B): Naproxen is heavily metabolized in the liver and undergoes both Phase I and Phase II metabolism. The first step involves demethylation of naproxen via CYP 1A2, 2C8, and 2C9. Both naproxen and desmethylnaproxen proceed to Phase II metabolism; however, desmethylnaproxen can form both acyl and phenolic glucoronide products, while naproxen only produces the acyl glucuronide. The acyl glucuronidation process involves UGT 1A1, 1A3, 1A6, 1A7, 1A9, 1A10 and 2B7, while phenolic glucuronidation is catalyzed by UGT 1A1, 1A7,1A9, and 1A10. Desmethylnaproxen also undergoes sulphation which is mediated by SULT 1A1, 1B1 and 1E1. •Route of elimination (Drug A): Bupropion is extensively metabolized in humans. Oxidation of the bupropion side chain results in the formation of a glycine conjugate of metachlorobenzoic acid, which is then excreted as the major urinary metabolite. Following oral administration of 200 mg of 14C-bupropion in humans, 87% and 10% of the radioactive dose were recovered in the urine and feces, respectively. However, the fraction of the oral dose of bupropion excreted unchanged was only 0.5%, a finding consistent with the extensive metabolism of bupropion. •Route of elimination (Drug B): After oral administration, about 95% of naproxen and it's metabolites can be recovered in the urine with 66-92% recovered as conjugated metabolite and less than 1% recovered as naproxen or desmethylnaproxen. Less than 5% of naproxen is excreted in the feces. •Half-life (Drug A): 24 hours •Half-life (Drug B): The elimination half-life of naproxen is reported to be 12-17 hours. •Clearance (Drug A): No clearance available •Clearance (Drug B): Naproxen is cleared at a rate of 0.13 mL/min/kg. •Toxicity (Drug A): Symptoms of overdose include seizures, hallucinations, loss of consciousness, tachycardia, and cardiac arrest. •Toxicity (Drug B): Although the over-the-counter (OTC) availability of naproxen provides convenience to patients, it also increases the likelihood of overdose. Thankfully, the extent of overdose is typically mild with adverse effects normally limited to drowsiness, lethargy, epigastric pain, nausea and vomiting. Although there is no antidote for naproxen overdose, symptoms will typically subside with appropriate supportive care. Naproxen is classified as Category B during the first 2 trimesters of pregnancy, and as Category D during the third trimester. Naproxen is contraindicated in the 3rd trimester since it increases the risk of premature closure of the fetal ductus arteriosus and should be avoided in pregnant women starting at 30 weeks gestation. •Brand Names (Drug A): Aplenzin, Auvelity, Budeprion, Contrave, Forfivo, Wellbutrin, Zyban •Brand Names (Drug B): Aleve, Aleve PM, Aleve-D, Anaprox, Naprelan, Naprosyn, Sallus, Sudafed Sinus & Pain, Treximet, Vimovo •Synonyms (Drug A): No synonyms listed •Synonyms (Drug B): (S)-Naproxen Naprolag Naproxen Naproxène Naproxeno Naproxenum •Summary (Drug A): Bupropion is a norepinephrine and dopamine reuptake inhibitor used in the treatment of major depressive disorder (MDD), seasonal affective disorder (SAD), and as an aid to smoking cessation. •Summary (Drug B): Naproxen is an NSAID used to treat rheumatoid arthritis, osteoarthritis, ankylosing spondylitis, polyarticular juvenile idiopathic arthritis, tendinitis, bursitis, acute gout, primary dysmenorrhea, and mild to moderate pain. Output: The subject drug is a nephrotoxic agent that may potentially impair renal function and decrease the excretion of drugs that mainly undergo renal excretion as the principal mode of clearance, such as the affected drug. Attenuated renal excretion of the affected drug may increase drug concentrations, leading to an elevated risk for drug-related adverse effects. The severity of the interaction is minor.

Does Bupropion and Naratriptan interact?

•Drug A: Bupropion •Drug B: Naratriptan •Severity: MODERATE •Description: The risk or severity of CNS depression can be increased when Naratriptan is combined with Bupropion. •Extended Description: Central nervous system (CNS) depressants can cause sedation, falls, respiratory depression, coma, and death.2,3 The potential interaction between a CNS depressant and another CNS depressant drug due to synergistic effects is well documented in the literature, although the risk and severity of CNS depression vary from each drug. The subject and affected drugs are both CNS depressants that, when co-administered, may result in a more profound CNS depression. As the risk and severity of CNS depression resulting from the combined use of CNS depressants vary from each agent, each interaction between CNS depressants should be considered individually. •Indication (Drug A): Bupropion is indicated for the treatment of major depressive disorder (MDD), seasonal affective disorder (SAD), and as an aid to smoking cessation. When used in combination with naltrexone as the marketed product ContraveⓇ, bupropion is indicated as an adjunct to a reduced-calorie diet and increased physical activity for chronic weight management in adults with an initial body mass index (BMI) of: 30 kg/m^2 or greater (obese) or 27 kg/m^2 or greater (overweight) in the presence of at least one weight-related comorbid condition (e.g., hypertension, type 2 diabetes mellitus, or dyslipidemia). Bupropion is also used off-label as a first-line treatment in patients with ADHD and comorbid bipolar disorder when used as an adjunct to mood stabilizers. •Indication (Drug B): For the acute treatment of migraine attacks with or without aura in adults. •Pharmacodynamics (Drug A): Bupropion is chemically unrelated to tricyclic, tetracyclic, selective serotonin re-uptake inhibitors, or other known antidepressant agents. Compared to classical tricyclic antidepressants, Bupropion is a relatively weak inhibitor of the neuronal uptake of norepinephrine and dopamine. In addition, Bupropion does not inhibit monoamine oxidase. Bupropion has been found to be essentially inactive at the serotonin transporter (SERT)(IC50 >10 000 nM), however both bupropion and its primary metabolite hydroxybupropion have been found to block the function of cation-selective serotonin type 3A receptors (5-HT3ARs). Bupropion produces dose-related central nervous system (CNS) stimulant effects in animals, as evidenced by increased locomotor activity, increased rates of responding in various schedule-controlled operant behaviour tasks, and, at high doses, induction of mild stereotyped behaviour. Due to these stimulant effects and selective activity at dopamine and norepinephrine receptors, bupropion has been identified as having an abuse potential. Bupropion has a similar structure to the controlled substance Cathinone, and has been identified as having mild amphetamine-like activity, particularly when inhaled or injected. Bupropion is also known to lower the seizure threshold, making any pre-existing seizure conditions a contraindication to its use. This risk is exacerbated when bupropion is combined with other drugs or substances that lower the seizure threshold, such as cocaine, or in clinical situations that would increase the risk of a seizure such as abrupt alcohol or benzodiazepine withdrawal. As norepinephrine has been shown to have anticonvulsant properties, bupropion's inhibitory effects on NET are thought to contribute to its pro-convulsant activity. Bupropion has been shown to increase blood pressure and pose a risk for exacerbation of unmanaged or pre-existing hypertension, however, clinical trials of bupropion in smokers with CVD have not identified an increased incidence of CV events including stroke or heart attack. In clinical trials, the mean increase in systolic blood pressure associated with the use of bupropion was found to be 1.3 mmHg. •Pharmacodynamics (Drug B): Naratriptan is a selective agonist of serotonin (5-hydroxytryptamine; 5-HT) type 1B and 1D receptors. It is structurally and pharmacologically related to other selective 5-HT1B/1D receptor agonist. Naratriptan has only a weak affinity for 5-HT 1A, 5-HT 5A, and 5-HT 7 receptors and no significant affinity or pharmacological activity at 5-HT 2, 5-HT 3 or 5-HT 4 receptor subtypes or at alpha1-, alpha2-, or beta-adrenergic, dopamine1,; dopamine2; muscarinic, or benzodiazepine receptors. This action in humans correlates with the relief of migraine headache. In addition to causing vasoconstriction, experimental data from animal studies show that Naratriptan also activates 5-HT 1 receptors on peripheral terminals of the trigeminal nerve innervating cranial blood vessels, which may also contribute to the antimigrainous effect of Naratriptan in humans. •Mechanism of action (Drug A): Bupropion is a norepinephrine/dopamine-reuptake inhibitor (NDRI) that exerts its pharmacological effects by weakly inhibiting the enzymes involved in the uptake of the neurotransmitters norepinephrine and dopamine from the synaptic cleft, therefore prolonging their duration of action within the neuronal synapse and the downstream effects of these neurotransmitters. More specifically, bupropion binds to the norepinephrine transporter (NET) and the dopamine transporter (DAT). Bupropion was originally classified as an "atypical" antidepressant because it does not exert the same effects as the classical antidepressants such as Monoamine Oxidase Inhibitors (MAOIs), Tricyclic Antidepressants (TCAs), or Selective Serotonin Reuptake Inhibitors (SSRIs). While it has comparable effectiveness to typical first-line options for the treatment of depression such as SSRIs, bupropion is a unique option for the treatment of MDD as it lacks any clinically relevant serotonergic effects, typical of other mood medications, or any effects on histamine or adrenaline receptors. Lack of activity at these receptors results in a more tolerable side effect profile; bupropion is less likely to cause sexual side effects, sedation, or weight gain as compared to SSRIs or TCAs, for example. When used as an aid to smoking cessation, bupropion is thought to confer its anti-craving and anti-withdrawal effects by inhibiting dopamine reuptake, which is thought to be involved in the reward pathways associated with nicotine, and through the antagonism of the nicotinic acetylcholinergic receptor (AChR), thereby blunting the effects of nicotine. Furthermore, the stimulatory effects produced by bupropion in the central nervous system are similar to nicotine's effects, making low doses of bupropion a suitable option as a nicotine substitute. When used in combination with naltrexone in the marketed product ContraveⓇ for chronic weight management, the two components are thought to have effects on areas of the brain involved in the regulation of food intake. This includes the hypothalamus, which is involved in appetite regulation, and the mesolimbic dopamine circuit, which is involved in reward pathways. Studies have shown that the combined activity of bupropion and naltrexone increase the firing rate of hypothalamic pro-opiomelanocortin (POMC) neurons and blockade of opioid receptor-mediated POMC auto-inhibition, which are associated with a reduction in food intake and increased energy expenditure. This combination was also found to reduce food intake when injected directly into the ventral tegmental area of the mesolimbic circuit in mice, which is an area associated with the regulation of reward pathways. •Mechanism of action (Drug B): Three distinct pharmacological actions have been implicated in the antimigraine effect of the triptans: (1) stimulation of presynaptic 5-HT1D receptors, which serves to inhibit both dural vasodilation and inflammation; (2) direct inhibition of trigeminal nuclei cell excitability via 5-HT1B/1D receptor agonism in the brainstem and (3) vasoconstriction of meningeal, dural, cerebral or pial vessels as a result of vascular 5-HT1B receptor agonism. •Absorption (Drug A): Bupropion is currently available in 3 distinct, but bioequivalent formulations: immediate release (IR), sustained-release (SR), and extended-release (XL). Immediate Release Formulation In humans, following oral administration of bupropion hydrochloride tablets, peak plasma bupropion concentrations are usually achieved within 2 hours. IR formulations provide a short duration of action and are therefore generally dosed three times per day. Sustained Release Formulation In humans, following oral administration of bupropion hydrochloride sustained-release tablets (SR), peak plasma concentration (Cmax) of bupropion is usually achieved within 3 hours. SR formulations provide a 12-hour extended release of medication and are therefore generally dosed twice per day. Extended Release Formulation Following single oral administration of bupropion hydrochloride extended-release tablets (XL) to healthy volunteers, the median time to peak plasma concentrations for bupropion was approximately 5 hours. The presence of food did not affect the peak concentration or area under the curve of bupropion. XL formulations provide a 24-hour extended release of medication and are therefore generally dosed once per day/ In a trial comparing chronic dosing with bupropion hydrochloride extended-release tablets (SR) 150 mg twice daily to bupropion immediate-release formulation 100 mg 3 times daily, the steady state Cmax for bupropion after bupropion hydrochloride sustained-release tablets (SR) administration was approximately 85% of those achieved after bupropion immediate-release formulation administration. Exposure (AUC) to bupropion was equivalent for both formulations. Bioequivalence was also demonstrated for all three major active metabolites (i.e., hydroxybupropion, threohydrobupropion and erythrohydrobupropion) for both Cmax and AUC. Thus, at steady state, bupropion hydrochloride sustained-release tablets (SR) given twice daily, and the immediate-release formulation of bupropion given 3 times daily, are essentially bioequivalent for both bupropion and the 3 quantitatively important metabolites. Furthermore, in a study comparing 14-day dosing with bupropion hydrochloride extended-release tablets (XL), 300 mg once-daily to the immediate-release formulation of bupropion at 100 mg 3 times daily, equivalence was demonstrated for peak plasma concentration and area under the curve for bupropion and the three metabolites (hydroxybupropion, threohydrobupropion, and erythrohydrobupropion). Additionally, in a study comparing 14-day dosing with bupropion hydrochloride extended-release tablets (XL) 300 mg once daily to the sustained-release formulation of bupropion at 150 mg 2 times daily, equivalence was demonstrated for peak plasma concentration and area under the curve for bupropion and the three metabolites. Bupropion hydrochloride extended-release tablets (SR) can be taken with or without food. Bupropion Cmax and AUC were increased by 11% to 35% and 16% to 19%, respectively, when bupropion hydrochloride extended-release tablets (SR) was administered with food to healthy volunteers in three trials. The food effect is not considered clinically significant. Following a single-dose administration of bupropion hydrochloride extended-release tablets (SR) in humans, Cmax of bupropion's metabolite hydroxybupropion occurs approximately 6 hours post-dose and is approximately 10 times the peak level of the parent drug at steady state. The elimination half-life of hydroxybupropion is approximately 20 (±5) hours and its AUC at steady state is about 17 times that of bupropion. The times to peak concentrations for the erythrohydrobupropion and threohydrobupropion metabolites are similar to that of the hydroxybupropion metabolite. However, their elimination half-lives are longer, 33(±10) and 37 (±13) hours, respectively, and steady-state AUCs are 1.5 and 7 times that of bupropion, respectively. •Absorption (Drug B): Well absorbed (74% oral biovaility), absorption is rapid with peak plasma concentrations after 2-5 hours. The rate of absorption is slower during a migraine attack. •Volume of distribution (Drug A): No volume of distribution available •Volume of distribution (Drug B): 170 L •Protein binding (Drug A): In vitro tests show that bupropion is 84% bound to human plasma proteins at concentrations up to 200 mcg per mL. The extent of protein binding of the hydroxybupropion metabolite is similar to that for bupropion, whereas the extent of protein binding of the threohydrobupropion metabolite is about half that seen with bupropion. •Protein binding (Drug B): 28%-31% (over the concentration range of 50 to 1000 ng/mL) •Metabolism (Drug A): Bupropion is extensively metabolized in humans. Three metabolites are active: hydroxybupropion, which is formed via hydroxylation of the tert-butyl group of bupropion, and the amino-alcohol isomers, threohydrobupropion and erythrohydrobupropion, which are formed via reduction of the carbonyl group. In vitro findings suggest that CYP2B6 is the principal isoenzyme involved in the formation of hydroxybupropion, while cytochrome P450 enzymes are not involved in the formation of threohydrobupropion. Hydroxybupropion has been shown to have the same affinity as bupropion for the norepinephrine transporter (NET) but approximately 50% of its antidepressant activity despite reaching concentrations of ~10-fold higher than that of the parent drug. Oxidation of the bupropion side chain results in the formation of a glycine conjugate of meta-chlorobenzoic acid, which is then excreted as the major urinary metabolite. The potency and toxicity of the metabolites relative to bupropion have not been fully characterized. However, it has been demonstrated in an antidepressant screening test in mice that hydroxybupropion is one-half as potent as bupropion, while threohydrobupropion and erythrohydrobupropion are 5-fold less potent than bupropion. This may be of clinical importance because the plasma concentrations of the metabolites are as high as or higher than those of bupropion. Bupropion and its metabolites exhibit linear kinetics following chronic administration of 300 to 450 mg per day. •Metabolism (Drug B): Primarily hepatic. In vitro, naratriptan is metabolized by a wide range of cytochrome P450 isoenzymes into a number of inactive metabolites. •Route of elimination (Drug A): Bupropion is extensively metabolized in humans. Oxidation of the bupropion side chain results in the formation of a glycine conjugate of metachlorobenzoic acid, which is then excreted as the major urinary metabolite. Following oral administration of 200 mg of 14C-bupropion in humans, 87% and 10% of the radioactive dose were recovered in the urine and feces, respectively. However, the fraction of the oral dose of bupropion excreted unchanged was only 0.5%, a finding consistent with the extensive metabolism of bupropion. •Route of elimination (Drug B): No route of elimination available •Half-life (Drug A): 24 hours •Half-life (Drug B): 5-8 hours •Clearance (Drug A): No clearance available •Clearance (Drug B): 6.6 mL/min/kg •Toxicity (Drug A): Symptoms of overdose include seizures, hallucinations, loss of consciousness, tachycardia, and cardiac arrest. •Toxicity (Drug B): Symptoms of overdose include light-headedness, loss of coordination, tension in the neck, and tiredness. •Brand Names (Drug A): Aplenzin, Auvelity, Budeprion, Contrave, Forfivo, Wellbutrin, Zyban •Brand Names (Drug B): No brand names available •Synonyms (Drug A): No synonyms listed •Synonyms (Drug B): Naratriptán Naratriptan Naratriptanum •Summary (Drug A): Bupropion is a norepinephrine and dopamine reuptake inhibitor used in the treatment of major depressive disorder (MDD), seasonal affective disorder (SAD), and as an aid to smoking cessation. •Summary (Drug B): Naratriptan is a 5-HT1B/1D receptor agonist used to treat migraines.

Central nervous system (CNS) depressants can cause sedation, falls, respiratory depression, coma, and death.2,3 The potential interaction between a CNS depressant and another CNS depressant drug due to synergistic effects is well documented in the literature, although the risk and severity of CNS depression vary from each drug. The subject and affected drugs are both CNS depressants that, when co-administered, may result in a more profound CNS depression. As the risk and severity of CNS depression resulting from the combined use of CNS depressants vary from each agent, each interaction between CNS depressants should be considered individually. The severity of the interaction is moderate.

Question: Does Bupropion and Naratriptan interact? Information: •Drug A: Bupropion •Drug B: Naratriptan •Severity: MODERATE •Description: The risk or severity of CNS depression can be increased when Naratriptan is combined with Bupropion. •Extended Description: Central nervous system (CNS) depressants can cause sedation, falls, respiratory depression, coma, and death.2,3 The potential interaction between a CNS depressant and another CNS depressant drug due to synergistic effects is well documented in the literature, although the risk and severity of CNS depression vary from each drug. The subject and affected drugs are both CNS depressants that, when co-administered, may result in a more profound CNS depression. As the risk and severity of CNS depression resulting from the combined use of CNS depressants vary from each agent, each interaction between CNS depressants should be considered individually. •Indication (Drug A): Bupropion is indicated for the treatment of major depressive disorder (MDD), seasonal affective disorder (SAD), and as an aid to smoking cessation. When used in combination with naltrexone as the marketed product ContraveⓇ, bupropion is indicated as an adjunct to a reduced-calorie diet and increased physical activity for chronic weight management in adults with an initial body mass index (BMI) of: 30 kg/m^2 or greater (obese) or 27 kg/m^2 or greater (overweight) in the presence of at least one weight-related comorbid condition (e.g., hypertension, type 2 diabetes mellitus, or dyslipidemia). Bupropion is also used off-label as a first-line treatment in patients with ADHD and comorbid bipolar disorder when used as an adjunct to mood stabilizers. •Indication (Drug B): For the acute treatment of migraine attacks with or without aura in adults. •Pharmacodynamics (Drug A): Bupropion is chemically unrelated to tricyclic, tetracyclic, selective serotonin re-uptake inhibitors, or other known antidepressant agents. Compared to classical tricyclic antidepressants, Bupropion is a relatively weak inhibitor of the neuronal uptake of norepinephrine and dopamine. In addition, Bupropion does not inhibit monoamine oxidase. Bupropion has been found to be essentially inactive at the serotonin transporter (SERT)(IC50 >10 000 nM), however both bupropion and its primary metabolite hydroxybupropion have been found to block the function of cation-selective serotonin type 3A receptors (5-HT3ARs). Bupropion produces dose-related central nervous system (CNS) stimulant effects in animals, as evidenced by increased locomotor activity, increased rates of responding in various schedule-controlled operant behaviour tasks, and, at high doses, induction of mild stereotyped behaviour. Due to these stimulant effects and selective activity at dopamine and norepinephrine receptors, bupropion has been identified as having an abuse potential. Bupropion has a similar structure to the controlled substance Cathinone, and has been identified as having mild amphetamine-like activity, particularly when inhaled or injected. Bupropion is also known to lower the seizure threshold, making any pre-existing seizure conditions a contraindication to its use. This risk is exacerbated when bupropion is combined with other drugs or substances that lower the seizure threshold, such as cocaine, or in clinical situations that would increase the risk of a seizure such as abrupt alcohol or benzodiazepine withdrawal. As norepinephrine has been shown to have anticonvulsant properties, bupropion's inhibitory effects on NET are thought to contribute to its pro-convulsant activity. Bupropion has been shown to increase blood pressure and pose a risk for exacerbation of unmanaged or pre-existing hypertension, however, clinical trials of bupropion in smokers with CVD have not identified an increased incidence of CV events including stroke or heart attack. In clinical trials, the mean increase in systolic blood pressure associated with the use of bupropion was found to be 1.3 mmHg. •Pharmacodynamics (Drug B): Naratriptan is a selective agonist of serotonin (5-hydroxytryptamine; 5-HT) type 1B and 1D receptors. It is structurally and pharmacologically related to other selective 5-HT1B/1D receptor agonist. Naratriptan has only a weak affinity for 5-HT 1A, 5-HT 5A, and 5-HT 7 receptors and no significant affinity or pharmacological activity at 5-HT 2, 5-HT 3 or 5-HT 4 receptor subtypes or at alpha1-, alpha2-, or beta-adrenergic, dopamine1,; dopamine2; muscarinic, or benzodiazepine receptors. This action in humans correlates with the relief of migraine headache. In addition to causing vasoconstriction, experimental data from animal studies show that Naratriptan also activates 5-HT 1 receptors on peripheral terminals of the trigeminal nerve innervating cranial blood vessels, which may also contribute to the antimigrainous effect of Naratriptan in humans. •Mechanism of action (Drug A): Bupropion is a norepinephrine/dopamine-reuptake inhibitor (NDRI) that exerts its pharmacological effects by weakly inhibiting the enzymes involved in the uptake of the neurotransmitters norepinephrine and dopamine from the synaptic cleft, therefore prolonging their duration of action within the neuronal synapse and the downstream effects of these neurotransmitters. More specifically, bupropion binds to the norepinephrine transporter (NET) and the dopamine transporter (DAT). Bupropion was originally classified as an "atypical" antidepressant because it does not exert the same effects as the classical antidepressants such as Monoamine Oxidase Inhibitors (MAOIs), Tricyclic Antidepressants (TCAs), or Selective Serotonin Reuptake Inhibitors (SSRIs). While it has comparable effectiveness to typical first-line options for the treatment of depression such as SSRIs, bupropion is a unique option for the treatment of MDD as it lacks any clinically relevant serotonergic effects, typical of other mood medications, or any effects on histamine or adrenaline receptors. Lack of activity at these receptors results in a more tolerable side effect profile; bupropion is less likely to cause sexual side effects, sedation, or weight gain as compared to SSRIs or TCAs, for example. When used as an aid to smoking cessation, bupropion is thought to confer its anti-craving and anti-withdrawal effects by inhibiting dopamine reuptake, which is thought to be involved in the reward pathways associated with nicotine, and through the antagonism of the nicotinic acetylcholinergic receptor (AChR), thereby blunting the effects of nicotine. Furthermore, the stimulatory effects produced by bupropion in the central nervous system are similar to nicotine's effects, making low doses of bupropion a suitable option as a nicotine substitute. When used in combination with naltrexone in the marketed product ContraveⓇ for chronic weight management, the two components are thought to have effects on areas of the brain involved in the regulation of food intake. This includes the hypothalamus, which is involved in appetite regulation, and the mesolimbic dopamine circuit, which is involved in reward pathways. Studies have shown that the combined activity of bupropion and naltrexone increase the firing rate of hypothalamic pro-opiomelanocortin (POMC) neurons and blockade of opioid receptor-mediated POMC auto-inhibition, which are associated with a reduction in food intake and increased energy expenditure. This combination was also found to reduce food intake when injected directly into the ventral tegmental area of the mesolimbic circuit in mice, which is an area associated with the regulation of reward pathways. •Mechanism of action (Drug B): Three distinct pharmacological actions have been implicated in the antimigraine effect of the triptans: (1) stimulation of presynaptic 5-HT1D receptors, which serves to inhibit both dural vasodilation and inflammation; (2) direct inhibition of trigeminal nuclei cell excitability via 5-HT1B/1D receptor agonism in the brainstem and (3) vasoconstriction of meningeal, dural, cerebral or pial vessels as a result of vascular 5-HT1B receptor agonism. •Absorption (Drug A): Bupropion is currently available in 3 distinct, but bioequivalent formulations: immediate release (IR), sustained-release (SR), and extended-release (XL). Immediate Release Formulation In humans, following oral administration of bupropion hydrochloride tablets, peak plasma bupropion concentrations are usually achieved within 2 hours. IR formulations provide a short duration of action and are therefore generally dosed three times per day. Sustained Release Formulation In humans, following oral administration of bupropion hydrochloride sustained-release tablets (SR), peak plasma concentration (Cmax) of bupropion is usually achieved within 3 hours. SR formulations provide a 12-hour extended release of medication and are therefore generally dosed twice per day. Extended Release Formulation Following single oral administration of bupropion hydrochloride extended-release tablets (XL) to healthy volunteers, the median time to peak plasma concentrations for bupropion was approximately 5 hours. The presence of food did not affect the peak concentration or area under the curve of bupropion. XL formulations provide a 24-hour extended release of medication and are therefore generally dosed once per day/ In a trial comparing chronic dosing with bupropion hydrochloride extended-release tablets (SR) 150 mg twice daily to bupropion immediate-release formulation 100 mg 3 times daily, the steady state Cmax for bupropion after bupropion hydrochloride sustained-release tablets (SR) administration was approximately 85% of those achieved after bupropion immediate-release formulation administration. Exposure (AUC) to bupropion was equivalent for both formulations. Bioequivalence was also demonstrated for all three major active metabolites (i.e., hydroxybupropion, threohydrobupropion and erythrohydrobupropion) for both Cmax and AUC. Thus, at steady state, bupropion hydrochloride sustained-release tablets (SR) given twice daily, and the immediate-release formulation of bupropion given 3 times daily, are essentially bioequivalent for both bupropion and the 3 quantitatively important metabolites. Furthermore, in a study comparing 14-day dosing with bupropion hydrochloride extended-release tablets (XL), 300 mg once-daily to the immediate-release formulation of bupropion at 100 mg 3 times daily, equivalence was demonstrated for peak plasma concentration and area under the curve for bupropion and the three metabolites (hydroxybupropion, threohydrobupropion, and erythrohydrobupropion). Additionally, in a study comparing 14-day dosing with bupropion hydrochloride extended-release tablets (XL) 300 mg once daily to the sustained-release formulation of bupropion at 150 mg 2 times daily, equivalence was demonstrated for peak plasma concentration and area under the curve for bupropion and the three metabolites. Bupropion hydrochloride extended-release tablets (SR) can be taken with or without food. Bupropion Cmax and AUC were increased by 11% to 35% and 16% to 19%, respectively, when bupropion hydrochloride extended-release tablets (SR) was administered with food to healthy volunteers in three trials. The food effect is not considered clinically significant. Following a single-dose administration of bupropion hydrochloride extended-release tablets (SR) in humans, Cmax of bupropion's metabolite hydroxybupropion occurs approximately 6 hours post-dose and is approximately 10 times the peak level of the parent drug at steady state. The elimination half-life of hydroxybupropion is approximately 20 (±5) hours and its AUC at steady state is about 17 times that of bupropion. The times to peak concentrations for the erythrohydrobupropion and threohydrobupropion metabolites are similar to that of the hydroxybupropion metabolite. However, their elimination half-lives are longer, 33(±10) and 37 (±13) hours, respectively, and steady-state AUCs are 1.5 and 7 times that of bupropion, respectively. •Absorption (Drug B): Well absorbed (74% oral biovaility), absorption is rapid with peak plasma concentrations after 2-5 hours. The rate of absorption is slower during a migraine attack. •Volume of distribution (Drug A): No volume of distribution available •Volume of distribution (Drug B): 170 L •Protein binding (Drug A): In vitro tests show that bupropion is 84% bound to human plasma proteins at concentrations up to 200 mcg per mL. The extent of protein binding of the hydroxybupropion metabolite is similar to that for bupropion, whereas the extent of protein binding of the threohydrobupropion metabolite is about half that seen with bupropion. •Protein binding (Drug B): 28%-31% (over the concentration range of 50 to 1000 ng/mL) •Metabolism (Drug A): Bupropion is extensively metabolized in humans. Three metabolites are active: hydroxybupropion, which is formed via hydroxylation of the tert-butyl group of bupropion, and the amino-alcohol isomers, threohydrobupropion and erythrohydrobupropion, which are formed via reduction of the carbonyl group. In vitro findings suggest that CYP2B6 is the principal isoenzyme involved in the formation of hydroxybupropion, while cytochrome P450 enzymes are not involved in the formation of threohydrobupropion. Hydroxybupropion has been shown to have the same affinity as bupropion for the norepinephrine transporter (NET) but approximately 50% of its antidepressant activity despite reaching concentrations of ~10-fold higher than that of the parent drug. Oxidation of the bupropion side chain results in the formation of a glycine conjugate of meta-chlorobenzoic acid, which is then excreted as the major urinary metabolite. The potency and toxicity of the metabolites relative to bupropion have not been fully characterized. However, it has been demonstrated in an antidepressant screening test in mice that hydroxybupropion is one-half as potent as bupropion, while threohydrobupropion and erythrohydrobupropion are 5-fold less potent than bupropion. This may be of clinical importance because the plasma concentrations of the metabolites are as high as or higher than those of bupropion. Bupropion and its metabolites exhibit linear kinetics following chronic administration of 300 to 450 mg per day. •Metabolism (Drug B): Primarily hepatic. In vitro, naratriptan is metabolized by a wide range of cytochrome P450 isoenzymes into a number of inactive metabolites. •Route of elimination (Drug A): Bupropion is extensively metabolized in humans. Oxidation of the bupropion side chain results in the formation of a glycine conjugate of metachlorobenzoic acid, which is then excreted as the major urinary metabolite. Following oral administration of 200 mg of 14C-bupropion in humans, 87% and 10% of the radioactive dose were recovered in the urine and feces, respectively. However, the fraction of the oral dose of bupropion excreted unchanged was only 0.5%, a finding consistent with the extensive metabolism of bupropion. •Route of elimination (Drug B): No route of elimination available •Half-life (Drug A): 24 hours •Half-life (Drug B): 5-8 hours •Clearance (Drug A): No clearance available •Clearance (Drug B): 6.6 mL/min/kg •Toxicity (Drug A): Symptoms of overdose include seizures, hallucinations, loss of consciousness, tachycardia, and cardiac arrest. •Toxicity (Drug B): Symptoms of overdose include light-headedness, loss of coordination, tension in the neck, and tiredness. •Brand Names (Drug A): Aplenzin, Auvelity, Budeprion, Contrave, Forfivo, Wellbutrin, Zyban •Brand Names (Drug B): No brand names available •Synonyms (Drug A): No synonyms listed •Synonyms (Drug B): Naratriptán Naratriptan Naratriptanum •Summary (Drug A): Bupropion is a norepinephrine and dopamine reuptake inhibitor used in the treatment of major depressive disorder (MDD), seasonal affective disorder (SAD), and as an aid to smoking cessation. •Summary (Drug B): Naratriptan is a 5-HT1B/1D receptor agonist used to treat migraines. Output: Central nervous system (CNS) depressants can cause sedation, falls, respiratory depression, coma, and death.2,3 The potential interaction between a CNS depressant and another CNS depressant drug due to synergistic effects is well documented in the literature, although the risk and severity of CNS depression vary from each drug. The subject and affected drugs are both CNS depressants that, when co-administered, may result in a more profound CNS depression. As the risk and severity of CNS depression resulting from the combined use of CNS depressants vary from each agent, each interaction between CNS depressants should be considered individually. The severity of the interaction is moderate.

Does Bupropion and Nateglinide interact?

•Drug A: Bupropion •Drug B: Nateglinide •Severity: MAJOR •Description: The metabolism of Nateglinide can be decreased when combined with Bupropion. •Extended Description: The subject drug is a strong CYP2D6 inhibitor and the affected drug is metabolized by CYP2D6. Concomitant administration may decrease the metabolism of the affected drug, which could increase serum concentrations as well as the risk and severity of adverse effects. •Indication (Drug A): Bupropion is indicated for the treatment of major depressive disorder (MDD), seasonal affective disorder (SAD), and as an aid to smoking cessation. When used in combination with naltrexone as the marketed product ContraveⓇ, bupropion is indicated as an adjunct to a reduced-calorie diet and increased physical activity for chronic weight management in adults with an initial body mass index (BMI) of: 30 kg/m^2 or greater (obese) or 27 kg/m^2 or greater (overweight) in the presence of at least one weight-related comorbid condition (e.g., hypertension, type 2 diabetes mellitus, or dyslipidemia). Bupropion is also used off-label as a first-line treatment in patients with ADHD and comorbid bipolar disorder when used as an adjunct to mood stabilizers. •Indication (Drug B): For the treatment of non-insulin dependent-diabetes mellitus in conjunction with diet and exercise. •Pharmacodynamics (Drug A): Bupropion is chemically unrelated to tricyclic, tetracyclic, selective serotonin re-uptake inhibitors, or other known antidepressant agents. Compared to classical tricyclic antidepressants, Bupropion is a relatively weak inhibitor of the neuronal uptake of norepinephrine and dopamine. In addition, Bupropion does not inhibit monoamine oxidase. Bupropion has been found to be essentially inactive at the serotonin transporter (SERT)(IC50 >10 000 nM), however both bupropion and its primary metabolite hydroxybupropion have been found to block the function of cation-selective serotonin type 3A receptors (5-HT3ARs). Bupropion produces dose-related central nervous system (CNS) stimulant effects in animals, as evidenced by increased locomotor activity, increased rates of responding in various schedule-controlled operant behaviour tasks, and, at high doses, induction of mild stereotyped behaviour. Due to these stimulant effects and selective activity at dopamine and norepinephrine receptors, bupropion has been identified as having an abuse potential. Bupropion has a similar structure to the controlled substance Cathinone, and has been identified as having mild amphetamine-like activity, particularly when inhaled or injected. Bupropion is also known to lower the seizure threshold, making any pre-existing seizure conditions a contraindication to its use. This risk is exacerbated when bupropion is combined with other drugs or substances that lower the seizure threshold, such as cocaine, or in clinical situations that would increase the risk of a seizure such as abrupt alcohol or benzodiazepine withdrawal. As norepinephrine has been shown to have anticonvulsant properties, bupropion's inhibitory effects on NET are thought to contribute to its pro-convulsant activity. Bupropion has been shown to increase blood pressure and pose a risk for exacerbation of unmanaged or pre-existing hypertension, however, clinical trials of bupropion in smokers with CVD have not identified an increased incidence of CV events including stroke or heart attack. In clinical trials, the mean increase in systolic blood pressure associated with the use of bupropion was found to be 1.3 mmHg. •Pharmacodynamics (Drug B): Insulin secretion by pancreatic β cells is partly controlled by cellular membrane potential. Membrane potential is regulated through an inverse relationship between the activity of cell membrane ATP-sensitive potassium channels (ABCC8) and extracellular glucose concentrations. Extracellular glucose enters the cell via GLUT2 (SLC2A2) transporters. Once inside the cell, glucose is metabolized to produce ATP. High concentrations of ATP inhibit ATP-sensitive potassium channels causing membrane depolarization. When extracellular glucose concentrations are low, ATP-sensitive potassium channels open causing membrane repolarization. High glucose concentrations cause ATP-sensitive potassium channels to close resulting in membrane depolarization and opening of L-type calcium channels. The influx of calcium ions stimulates calcium-dependent exocytosis of insulin granules. Nateglinide increases insulin release by inhibiting ATP-sensitive potassium channels in a glucose-dependent manner. •Mechanism of action (Drug A): Bupropion is a norepinephrine/dopamine-reuptake inhibitor (NDRI) that exerts its pharmacological effects by weakly inhibiting the enzymes involved in the uptake of the neurotransmitters norepinephrine and dopamine from the synaptic cleft, therefore prolonging their duration of action within the neuronal synapse and the downstream effects of these neurotransmitters. More specifically, bupropion binds to the norepinephrine transporter (NET) and the dopamine transporter (DAT). Bupropion was originally classified as an "atypical" antidepressant because it does not exert the same effects as the classical antidepressants such as Monoamine Oxidase Inhibitors (MAOIs), Tricyclic Antidepressants (TCAs), or Selective Serotonin Reuptake Inhibitors (SSRIs). While it has comparable effectiveness to typical first-line options for the treatment of depression such as SSRIs, bupropion is a unique option for the treatment of MDD as it lacks any clinically relevant serotonergic effects, typical of other mood medications, or any effects on histamine or adrenaline receptors. Lack of activity at these receptors results in a more tolerable side effect profile; bupropion is less likely to cause sexual side effects, sedation, or weight gain as compared to SSRIs or TCAs, for example. When used as an aid to smoking cessation, bupropion is thought to confer its anti-craving and anti-withdrawal effects by inhibiting dopamine reuptake, which is thought to be involved in the reward pathways associated with nicotine, and through the antagonism of the nicotinic acetylcholinergic receptor (AChR), thereby blunting the effects of nicotine. Furthermore, the stimulatory effects produced by bupropion in the central nervous system are similar to nicotine's effects, making low doses of bupropion a suitable option as a nicotine substitute. When used in combination with naltrexone in the marketed product ContraveⓇ for chronic weight management, the two components are thought to have effects on areas of the brain involved in the regulation of food intake. This includes the hypothalamus, which is involved in appetite regulation, and the mesolimbic dopamine circuit, which is involved in reward pathways. Studies have shown that the combined activity of bupropion and naltrexone increase the firing rate of hypothalamic pro-opiomelanocortin (POMC) neurons and blockade of opioid receptor-mediated POMC auto-inhibition, which are associated with a reduction in food intake and increased energy expenditure. This combination was also found to reduce food intake when injected directly into the ventral tegmental area of the mesolimbic circuit in mice, which is an area associated with the regulation of reward pathways. •Mechanism of action (Drug B): Nateglinide activity is dependent on the presence functioning β cells and glucose. In contrast to sulfonylurea insulin secretatogogues, nateglinide has no effect on insulin release in the absence of glucose. Rather, it potentiates the effect of extracellular glucose on ATP-sensitive potassium channel and has little effect on insulin levels between meals and overnight. As such, nateglinide is more effective at reducing postprandial blood glucose levels than fasting blood glucose levels and requires a longer duration of therapy (approximately one month) before decreases in fasting blood glucose are observed. The insulinotropic effects of nateglinide are highest at intermediate glucose levels (3 to 10 mmol/L) and it does not increase insulin release already stimulated by high glucose concentrations (greater than 15 mmol/L). Nateglinide appears to be selective for pancreatic β cells and does not appear to affect skeletal or cardiac muscle or thyroid tissue. •Absorption (Drug A): Bupropion is currently available in 3 distinct, but bioequivalent formulations: immediate release (IR), sustained-release (SR), and extended-release (XL). Immediate Release Formulation In humans, following oral administration of bupropion hydrochloride tablets, peak plasma bupropion concentrations are usually achieved within 2 hours. IR formulations provide a short duration of action and are therefore generally dosed three times per day. Sustained Release Formulation In humans, following oral administration of bupropion hydrochloride sustained-release tablets (SR), peak plasma concentration (Cmax) of bupropion is usually achieved within 3 hours. SR formulations provide a 12-hour extended release of medication and are therefore generally dosed twice per day. Extended Release Formulation Following single oral administration of bupropion hydrochloride extended-release tablets (XL) to healthy volunteers, the median time to peak plasma concentrations for bupropion was approximately 5 hours. The presence of food did not affect the peak concentration or area under the curve of bupropion. XL formulations provide a 24-hour extended release of medication and are therefore generally dosed once per day/ In a trial comparing chronic dosing with bupropion hydrochloride extended-release tablets (SR) 150 mg twice daily to bupropion immediate-release formulation 100 mg 3 times daily, the steady state Cmax for bupropion after bupropion hydrochloride sustained-release tablets (SR) administration was approximately 85% of those achieved after bupropion immediate-release formulation administration. Exposure (AUC) to bupropion was equivalent for both formulations. Bioequivalence was also demonstrated for all three major active metabolites (i.e., hydroxybupropion, threohydrobupropion and erythrohydrobupropion) for both Cmax and AUC. Thus, at steady state, bupropion hydrochloride sustained-release tablets (SR) given twice daily, and the immediate-release formulation of bupropion given 3 times daily, are essentially bioequivalent for both bupropion and the 3 quantitatively important metabolites. Furthermore, in a study comparing 14-day dosing with bupropion hydrochloride extended-release tablets (XL), 300 mg once-daily to the immediate-release formulation of bupropion at 100 mg 3 times daily, equivalence was demonstrated for peak plasma concentration and area under the curve for bupropion and the three metabolites (hydroxybupropion, threohydrobupropion, and erythrohydrobupropion). Additionally, in a study comparing 14-day dosing with bupropion hydrochloride extended-release tablets (XL) 300 mg once daily to the sustained-release formulation of bupropion at 150 mg 2 times daily, equivalence was demonstrated for peak plasma concentration and area under the curve for bupropion and the three metabolites. Bupropion hydrochloride extended-release tablets (SR) can be taken with or without food. Bupropion Cmax and AUC were increased by 11% to 35% and 16% to 19%, respectively, when bupropion hydrochloride extended-release tablets (SR) was administered with food to healthy volunteers in three trials. The food effect is not considered clinically significant. Following a single-dose administration of bupropion hydrochloride extended-release tablets (SR) in humans, Cmax of bupropion's metabolite hydroxybupropion occurs approximately 6 hours post-dose and is approximately 10 times the peak level of the parent drug at steady state. The elimination half-life of hydroxybupropion is approximately 20 (±5) hours and its AUC at steady state is about 17 times that of bupropion. The times to peak concentrations for the erythrohydrobupropion and threohydrobupropion metabolites are similar to that of the hydroxybupropion metabolite. However, their elimination half-lives are longer, 33(±10) and 37 (±13) hours, respectively, and steady-state AUCs are 1.5 and 7 times that of bupropion, respectively. •Absorption (Drug B): Rapidly absorbed following oral administration prior to a meal, absolute bioavailability is estimated to be approximately 73%. Peak plasma concentrations generally occur within 1 hour of oral administration. Onset of action is <20 minutes and the duration of action is approximately 4 hours. •Volume of distribution (Drug A): No volume of distribution available •Volume of distribution (Drug B): 10 liters in healthy subjects •Protein binding (Drug A): In vitro tests show that bupropion is 84% bound to human plasma proteins at concentrations up to 200 mcg per mL. The extent of protein binding of the hydroxybupropion metabolite is similar to that for bupropion, whereas the extent of protein binding of the threohydrobupropion metabolite is about half that seen with bupropion. •Protein binding (Drug B): 98% bound to serum proteins, primarily serum albumin and to a lesser extent α1 acid glycoprotein •Metabolism (Drug A): Bupropion is extensively metabolized in humans. Three metabolites are active: hydroxybupropion, which is formed via hydroxylation of the tert-butyl group of bupropion, and the amino-alcohol isomers, threohydrobupropion and erythrohydrobupropion, which are formed via reduction of the carbonyl group. In vitro findings suggest that CYP2B6 is the principal isoenzyme involved in the formation of hydroxybupropion, while cytochrome P450 enzymes are not involved in the formation of threohydrobupropion. Hydroxybupropion has been shown to have the same affinity as bupropion for the norepinephrine transporter (NET) but approximately 50% of its antidepressant activity despite reaching concentrations of ~10-fold higher than that of the parent drug. Oxidation of the bupropion side chain results in the formation of a glycine conjugate of meta-chlorobenzoic acid, which is then excreted as the major urinary metabolite. The potency and toxicity of the metabolites relative to bupropion have not been fully characterized. However, it has been demonstrated in an antidepressant screening test in mice that hydroxybupropion is one-half as potent as bupropion, while threohydrobupropion and erythrohydrobupropion are 5-fold less potent than bupropion. This may be of clinical importance because the plasma concentrations of the metabolites are as high as or higher than those of bupropion. Bupropion and its metabolites exhibit linear kinetics following chronic administration of 300 to 450 mg per day. •Metabolism (Drug B): Hepatic, via cytochrome P450 isoenzymes CYP2C9 (70%) and CYP3A4 (30%). Metabolism is via hydroxylation followed by glucuronidation. The major metabolites have less antidiabetic activity than nateglinide, but the isoprene minor metabolite has antidiabetic activity comparable to that of nateglinide. •Route of elimination (Drug A): Bupropion is extensively metabolized in humans. Oxidation of the bupropion side chain results in the formation of a glycine conjugate of metachlorobenzoic acid, which is then excreted as the major urinary metabolite. Following oral administration of 200 mg of 14C-bupropion in humans, 87% and 10% of the radioactive dose were recovered in the urine and feces, respectively. However, the fraction of the oral dose of bupropion excreted unchanged was only 0.5%, a finding consistent with the extensive metabolism of bupropion. •Route of elimination (Drug B): Urine (83%) and feces (10%) •Half-life (Drug A): 24 hours •Half-life (Drug B): 1.5 hours •Clearance (Drug A): No clearance available •Clearance (Drug B): No clearance available •Toxicity (Drug A): Symptoms of overdose include seizures, hallucinations, loss of consciousness, tachycardia, and cardiac arrest. •Toxicity (Drug B): An overdose may result in an exaggerated glucose-lowering effect with the development of hypoglycemic symptoms. •Brand Names (Drug A): Aplenzin, Auvelity, Budeprion, Contrave, Forfivo, Wellbutrin, Zyban •Brand Names (Drug B): No brand names available •Synonyms (Drug A): No synonyms listed •Synonyms (Drug B): No synonyms listed •Summary (Drug A): Bupropion is a norepinephrine and dopamine reuptake inhibitor used in the treatment of major depressive disorder (MDD), seasonal affective disorder (SAD), and as an aid to smoking cessation. •Summary (Drug B): Nateglinide is a meglitinide used to treat non insulin dependent diabetes mellitus.

The subject drug is a strong CYP2D6 inhibitor and the affected drug is metabolized by CYP2D6. Concomitant administration may decrease the metabolism of the affected drug, which could increase serum concentrations as well as the risk and severity of adverse effects. The severity of the interaction is major.

Question: Does Bupropion and Nateglinide interact? Information: •Drug A: Bupropion •Drug B: Nateglinide •Severity: MAJOR •Description: The metabolism of Nateglinide can be decreased when combined with Bupropion. •Extended Description: The subject drug is a strong CYP2D6 inhibitor and the affected drug is metabolized by CYP2D6. Concomitant administration may decrease the metabolism of the affected drug, which could increase serum concentrations as well as the risk and severity of adverse effects. •Indication (Drug A): Bupropion is indicated for the treatment of major depressive disorder (MDD), seasonal affective disorder (SAD), and as an aid to smoking cessation. When used in combination with naltrexone as the marketed product ContraveⓇ, bupropion is indicated as an adjunct to a reduced-calorie diet and increased physical activity for chronic weight management in adults with an initial body mass index (BMI) of: 30 kg/m^2 or greater (obese) or 27 kg/m^2 or greater (overweight) in the presence of at least one weight-related comorbid condition (e.g., hypertension, type 2 diabetes mellitus, or dyslipidemia). Bupropion is also used off-label as a first-line treatment in patients with ADHD and comorbid bipolar disorder when used as an adjunct to mood stabilizers. •Indication (Drug B): For the treatment of non-insulin dependent-diabetes mellitus in conjunction with diet and exercise. •Pharmacodynamics (Drug A): Bupropion is chemically unrelated to tricyclic, tetracyclic, selective serotonin re-uptake inhibitors, or other known antidepressant agents. Compared to classical tricyclic antidepressants, Bupropion is a relatively weak inhibitor of the neuronal uptake of norepinephrine and dopamine. In addition, Bupropion does not inhibit monoamine oxidase. Bupropion has been found to be essentially inactive at the serotonin transporter (SERT)(IC50 >10 000 nM), however both bupropion and its primary metabolite hydroxybupropion have been found to block the function of cation-selective serotonin type 3A receptors (5-HT3ARs). Bupropion produces dose-related central nervous system (CNS) stimulant effects in animals, as evidenced by increased locomotor activity, increased rates of responding in various schedule-controlled operant behaviour tasks, and, at high doses, induction of mild stereotyped behaviour. Due to these stimulant effects and selective activity at dopamine and norepinephrine receptors, bupropion has been identified as having an abuse potential. Bupropion has a similar structure to the controlled substance Cathinone, and has been identified as having mild amphetamine-like activity, particularly when inhaled or injected. Bupropion is also known to lower the seizure threshold, making any pre-existing seizure conditions a contraindication to its use. This risk is exacerbated when bupropion is combined with other drugs or substances that lower the seizure threshold, such as cocaine, or in clinical situations that would increase the risk of a seizure such as abrupt alcohol or benzodiazepine withdrawal. As norepinephrine has been shown to have anticonvulsant properties, bupropion's inhibitory effects on NET are thought to contribute to its pro-convulsant activity. Bupropion has been shown to increase blood pressure and pose a risk for exacerbation of unmanaged or pre-existing hypertension, however, clinical trials of bupropion in smokers with CVD have not identified an increased incidence of CV events including stroke or heart attack. In clinical trials, the mean increase in systolic blood pressure associated with the use of bupropion was found to be 1.3 mmHg. •Pharmacodynamics (Drug B): Insulin secretion by pancreatic β cells is partly controlled by cellular membrane potential. Membrane potential is regulated through an inverse relationship between the activity of cell membrane ATP-sensitive potassium channels (ABCC8) and extracellular glucose concentrations. Extracellular glucose enters the cell via GLUT2 (SLC2A2) transporters. Once inside the cell, glucose is metabolized to produce ATP. High concentrations of ATP inhibit ATP-sensitive potassium channels causing membrane depolarization. When extracellular glucose concentrations are low, ATP-sensitive potassium channels open causing membrane repolarization. High glucose concentrations cause ATP-sensitive potassium channels to close resulting in membrane depolarization and opening of L-type calcium channels. The influx of calcium ions stimulates calcium-dependent exocytosis of insulin granules. Nateglinide increases insulin release by inhibiting ATP-sensitive potassium channels in a glucose-dependent manner. •Mechanism of action (Drug A): Bupropion is a norepinephrine/dopamine-reuptake inhibitor (NDRI) that exerts its pharmacological effects by weakly inhibiting the enzymes involved in the uptake of the neurotransmitters norepinephrine and dopamine from the synaptic cleft, therefore prolonging their duration of action within the neuronal synapse and the downstream effects of these neurotransmitters. More specifically, bupropion binds to the norepinephrine transporter (NET) and the dopamine transporter (DAT). Bupropion was originally classified as an "atypical" antidepressant because it does not exert the same effects as the classical antidepressants such as Monoamine Oxidase Inhibitors (MAOIs), Tricyclic Antidepressants (TCAs), or Selective Serotonin Reuptake Inhibitors (SSRIs). While it has comparable effectiveness to typical first-line options for the treatment of depression such as SSRIs, bupropion is a unique option for the treatment of MDD as it lacks any clinically relevant serotonergic effects, typical of other mood medications, or any effects on histamine or adrenaline receptors. Lack of activity at these receptors results in a more tolerable side effect profile; bupropion is less likely to cause sexual side effects, sedation, or weight gain as compared to SSRIs or TCAs, for example. When used as an aid to smoking cessation, bupropion is thought to confer its anti-craving and anti-withdrawal effects by inhibiting dopamine reuptake, which is thought to be involved in the reward pathways associated with nicotine, and through the antagonism of the nicotinic acetylcholinergic receptor (AChR), thereby blunting the effects of nicotine. Furthermore, the stimulatory effects produced by bupropion in the central nervous system are similar to nicotine's effects, making low doses of bupropion a suitable option as a nicotine substitute. When used in combination with naltrexone in the marketed product ContraveⓇ for chronic weight management, the two components are thought to have effects on areas of the brain involved in the regulation of food intake. This includes the hypothalamus, which is involved in appetite regulation, and the mesolimbic dopamine circuit, which is involved in reward pathways. Studies have shown that the combined activity of bupropion and naltrexone increase the firing rate of hypothalamic pro-opiomelanocortin (POMC) neurons and blockade of opioid receptor-mediated POMC auto-inhibition, which are associated with a reduction in food intake and increased energy expenditure. This combination was also found to reduce food intake when injected directly into the ventral tegmental area of the mesolimbic circuit in mice, which is an area associated with the regulation of reward pathways. •Mechanism of action (Drug B): Nateglinide activity is dependent on the presence functioning β cells and glucose. In contrast to sulfonylurea insulin secretatogogues, nateglinide has no effect on insulin release in the absence of glucose. Rather, it potentiates the effect of extracellular glucose on ATP-sensitive potassium channel and has little effect on insulin levels between meals and overnight. As such, nateglinide is more effective at reducing postprandial blood glucose levels than fasting blood glucose levels and requires a longer duration of therapy (approximately one month) before decreases in fasting blood glucose are observed. The insulinotropic effects of nateglinide are highest at intermediate glucose levels (3 to 10 mmol/L) and it does not increase insulin release already stimulated by high glucose concentrations (greater than 15 mmol/L). Nateglinide appears to be selective for pancreatic β cells and does not appear to affect skeletal or cardiac muscle or thyroid tissue. •Absorption (Drug A): Bupropion is currently available in 3 distinct, but bioequivalent formulations: immediate release (IR), sustained-release (SR), and extended-release (XL). Immediate Release Formulation In humans, following oral administration of bupropion hydrochloride tablets, peak plasma bupropion concentrations are usually achieved within 2 hours. IR formulations provide a short duration of action and are therefore generally dosed three times per day. Sustained Release Formulation In humans, following oral administration of bupropion hydrochloride sustained-release tablets (SR), peak plasma concentration (Cmax) of bupropion is usually achieved within 3 hours. SR formulations provide a 12-hour extended release of medication and are therefore generally dosed twice per day. Extended Release Formulation Following single oral administration of bupropion hydrochloride extended-release tablets (XL) to healthy volunteers, the median time to peak plasma concentrations for bupropion was approximately 5 hours. The presence of food did not affect the peak concentration or area under the curve of bupropion. XL formulations provide a 24-hour extended release of medication and are therefore generally dosed once per day/ In a trial comparing chronic dosing with bupropion hydrochloride extended-release tablets (SR) 150 mg twice daily to bupropion immediate-release formulation 100 mg 3 times daily, the steady state Cmax for bupropion after bupropion hydrochloride sustained-release tablets (SR) administration was approximately 85% of those achieved after bupropion immediate-release formulation administration. Exposure (AUC) to bupropion was equivalent for both formulations. Bioequivalence was also demonstrated for all three major active metabolites (i.e., hydroxybupropion, threohydrobupropion and erythrohydrobupropion) for both Cmax and AUC. Thus, at steady state, bupropion hydrochloride sustained-release tablets (SR) given twice daily, and the immediate-release formulation of bupropion given 3 times daily, are essentially bioequivalent for both bupropion and the 3 quantitatively important metabolites. Furthermore, in a study comparing 14-day dosing with bupropion hydrochloride extended-release tablets (XL), 300 mg once-daily to the immediate-release formulation of bupropion at 100 mg 3 times daily, equivalence was demonstrated for peak plasma concentration and area under the curve for bupropion and the three metabolites (hydroxybupropion, threohydrobupropion, and erythrohydrobupropion). Additionally, in a study comparing 14-day dosing with bupropion hydrochloride extended-release tablets (XL) 300 mg once daily to the sustained-release formulation of bupropion at 150 mg 2 times daily, equivalence was demonstrated for peak plasma concentration and area under the curve for bupropion and the three metabolites. Bupropion hydrochloride extended-release tablets (SR) can be taken with or without food. Bupropion Cmax and AUC were increased by 11% to 35% and 16% to 19%, respectively, when bupropion hydrochloride extended-release tablets (SR) was administered with food to healthy volunteers in three trials. The food effect is not considered clinically significant. Following a single-dose administration of bupropion hydrochloride extended-release tablets (SR) in humans, Cmax of bupropion's metabolite hydroxybupropion occurs approximately 6 hours post-dose and is approximately 10 times the peak level of the parent drug at steady state. The elimination half-life of hydroxybupropion is approximately 20 (±5) hours and its AUC at steady state is about 17 times that of bupropion. The times to peak concentrations for the erythrohydrobupropion and threohydrobupropion metabolites are similar to that of the hydroxybupropion metabolite. However, their elimination half-lives are longer, 33(±10) and 37 (±13) hours, respectively, and steady-state AUCs are 1.5 and 7 times that of bupropion, respectively. •Absorption (Drug B): Rapidly absorbed following oral administration prior to a meal, absolute bioavailability is estimated to be approximately 73%. Peak plasma concentrations generally occur within 1 hour of oral administration. Onset of action is <20 minutes and the duration of action is approximately 4 hours. •Volume of distribution (Drug A): No volume of distribution available •Volume of distribution (Drug B): 10 liters in healthy subjects •Protein binding (Drug A): In vitro tests show that bupropion is 84% bound to human plasma proteins at concentrations up to 200 mcg per mL. The extent of protein binding of the hydroxybupropion metabolite is similar to that for bupropion, whereas the extent of protein binding of the threohydrobupropion metabolite is about half that seen with bupropion. •Protein binding (Drug B): 98% bound to serum proteins, primarily serum albumin and to a lesser extent α1 acid glycoprotein •Metabolism (Drug A): Bupropion is extensively metabolized in humans. Three metabolites are active: hydroxybupropion, which is formed via hydroxylation of the tert-butyl group of bupropion, and the amino-alcohol isomers, threohydrobupropion and erythrohydrobupropion, which are formed via reduction of the carbonyl group. In vitro findings suggest that CYP2B6 is the principal isoenzyme involved in the formation of hydroxybupropion, while cytochrome P450 enzymes are not involved in the formation of threohydrobupropion. Hydroxybupropion has been shown to have the same affinity as bupropion for the norepinephrine transporter (NET) but approximately 50% of its antidepressant activity despite reaching concentrations of ~10-fold higher than that of the parent drug. Oxidation of the bupropion side chain results in the formation of a glycine conjugate of meta-chlorobenzoic acid, which is then excreted as the major urinary metabolite. The potency and toxicity of the metabolites relative to bupropion have not been fully characterized. However, it has been demonstrated in an antidepressant screening test in mice that hydroxybupropion is one-half as potent as bupropion, while threohydrobupropion and erythrohydrobupropion are 5-fold less potent than bupropion. This may be of clinical importance because the plasma concentrations of the metabolites are as high as or higher than those of bupropion. Bupropion and its metabolites exhibit linear kinetics following chronic administration of 300 to 450 mg per day. •Metabolism (Drug B): Hepatic, via cytochrome P450 isoenzymes CYP2C9 (70%) and CYP3A4 (30%). Metabolism is via hydroxylation followed by glucuronidation. The major metabolites have less antidiabetic activity than nateglinide, but the isoprene minor metabolite has antidiabetic activity comparable to that of nateglinide. •Route of elimination (Drug A): Bupropion is extensively metabolized in humans. Oxidation of the bupropion side chain results in the formation of a glycine conjugate of metachlorobenzoic acid, which is then excreted as the major urinary metabolite. Following oral administration of 200 mg of 14C-bupropion in humans, 87% and 10% of the radioactive dose were recovered in the urine and feces, respectively. However, the fraction of the oral dose of bupropion excreted unchanged was only 0.5%, a finding consistent with the extensive metabolism of bupropion. •Route of elimination (Drug B): Urine (83%) and feces (10%) •Half-life (Drug A): 24 hours •Half-life (Drug B): 1.5 hours •Clearance (Drug A): No clearance available •Clearance (Drug B): No clearance available •Toxicity (Drug A): Symptoms of overdose include seizures, hallucinations, loss of consciousness, tachycardia, and cardiac arrest. •Toxicity (Drug B): An overdose may result in an exaggerated glucose-lowering effect with the development of hypoglycemic symptoms. •Brand Names (Drug A): Aplenzin, Auvelity, Budeprion, Contrave, Forfivo, Wellbutrin, Zyban •Brand Names (Drug B): No brand names available •Synonyms (Drug A): No synonyms listed •Synonyms (Drug B): No synonyms listed •Summary (Drug A): Bupropion is a norepinephrine and dopamine reuptake inhibitor used in the treatment of major depressive disorder (MDD), seasonal affective disorder (SAD), and as an aid to smoking cessation. •Summary (Drug B): Nateglinide is a meglitinide used to treat non insulin dependent diabetes mellitus. Output: The subject drug is a strong CYP2D6 inhibitor and the affected drug is metabolized by CYP2D6. Concomitant administration may decrease the metabolism of the affected drug, which could increase serum concentrations as well as the risk and severity of adverse effects. The severity of the interaction is major.

Does Bupropion and Nebivolol interact?

•Drug A: Bupropion •Drug B: Nebivolol •Severity: MAJOR •Description: The metabolism of Nebivolol can be decreased when combined with Bupropion. •Extended Description: The subject drug is a strong CYP2D6 inhibitor and the affected drug is metabolized by CYP2D6. Concomitant administration may decrease the metabolism of the affected drug, which could increase serum concentrations as well as the risk and severity of adverse effects. •Indication (Drug A): Bupropion is indicated for the treatment of major depressive disorder (MDD), seasonal affective disorder (SAD), and as an aid to smoking cessation. When used in combination with naltrexone as the marketed product ContraveⓇ, bupropion is indicated as an adjunct to a reduced-calorie diet and increased physical activity for chronic weight management in adults with an initial body mass index (BMI) of: 30 kg/m^2 or greater (obese) or 27 kg/m^2 or greater (overweight) in the presence of at least one weight-related comorbid condition (e.g., hypertension, type 2 diabetes mellitus, or dyslipidemia). Bupropion is also used off-label as a first-line treatment in patients with ADHD and comorbid bipolar disorder when used as an adjunct to mood stabilizers. •Indication (Drug B): Nebivolol is indicated to treat hypertension. •Pharmacodynamics (Drug A): Bupropion is chemically unrelated to tricyclic, tetracyclic, selective serotonin re-uptake inhibitors, or other known antidepressant agents. Compared to classical tricyclic antidepressants, Bupropion is a relatively weak inhibitor of the neuronal uptake of norepinephrine and dopamine. In addition, Bupropion does not inhibit monoamine oxidase. Bupropion has been found to be essentially inactive at the serotonin transporter (SERT)(IC50 >10 000 nM), however both bupropion and its primary metabolite hydroxybupropion have been found to block the function of cation-selective serotonin type 3A receptors (5-HT3ARs). Bupropion produces dose-related central nervous system (CNS) stimulant effects in animals, as evidenced by increased locomotor activity, increased rates of responding in various schedule-controlled operant behaviour tasks, and, at high doses, induction of mild stereotyped behaviour. Due to these stimulant effects and selective activity at dopamine and norepinephrine receptors, bupropion has been identified as having an abuse potential. Bupropion has a similar structure to the controlled substance Cathinone, and has been identified as having mild amphetamine-like activity, particularly when inhaled or injected. Bupropion is also known to lower the seizure threshold, making any pre-existing seizure conditions a contraindication to its use. This risk is exacerbated when bupropion is combined with other drugs or substances that lower the seizure threshold, such as cocaine, or in clinical situations that would increase the risk of a seizure such as abrupt alcohol or benzodiazepine withdrawal. As norepinephrine has been shown to have anticonvulsant properties, bupropion's inhibitory effects on NET are thought to contribute to its pro-convulsant activity. Bupropion has been shown to increase blood pressure and pose a risk for exacerbation of unmanaged or pre-existing hypertension, however, clinical trials of bupropion in smokers with CVD have not identified an increased incidence of CV events including stroke or heart attack. In clinical trials, the mean increase in systolic blood pressure associated with the use of bupropion was found to be 1.3 mmHg. •Pharmacodynamics (Drug B): Nebivolol is a selective beta-1 adrenergic receptor antagonist that decreases vascular resistance, increases stroke volume and cardiac output, and does not negatively affect left ventricular function. It has a long duration of action as effects can be seen 48 hours after stopping the medication and a wide therapeutic window as patients generally take 5-40mg daily. Patients should not abruptly stop taking this medication as this may lead to exacerbation of coronary artery disease. Diabetic patients should monitor their blood glucose levels as beta blockers may mask signs of hypoglycemia. •Mechanism of action (Drug A): Bupropion is a norepinephrine/dopamine-reuptake inhibitor (NDRI) that exerts its pharmacological effects by weakly inhibiting the enzymes involved in the uptake of the neurotransmitters norepinephrine and dopamine from the synaptic cleft, therefore prolonging their duration of action within the neuronal synapse and the downstream effects of these neurotransmitters. More specifically, bupropion binds to the norepinephrine transporter (NET) and the dopamine transporter (DAT). Bupropion was originally classified as an "atypical" antidepressant because it does not exert the same effects as the classical antidepressants such as Monoamine Oxidase Inhibitors (MAOIs), Tricyclic Antidepressants (TCAs), or Selective Serotonin Reuptake Inhibitors (SSRIs). While it has comparable effectiveness to typical first-line options for the treatment of depression such as SSRIs, bupropion is a unique option for the treatment of MDD as it lacks any clinically relevant serotonergic effects, typical of other mood medications, or any effects on histamine or adrenaline receptors. Lack of activity at these receptors results in a more tolerable side effect profile; bupropion is less likely to cause sexual side effects, sedation, or weight gain as compared to SSRIs or TCAs, for example. When used as an aid to smoking cessation, bupropion is thought to confer its anti-craving and anti-withdrawal effects by inhibiting dopamine reuptake, which is thought to be involved in the reward pathways associated with nicotine, and through the antagonism of the nicotinic acetylcholinergic receptor (AChR), thereby blunting the effects of nicotine. Furthermore, the stimulatory effects produced by bupropion in the central nervous system are similar to nicotine's effects, making low doses of bupropion a suitable option as a nicotine substitute. When used in combination with naltrexone in the marketed product ContraveⓇ for chronic weight management, the two components are thought to have effects on areas of the brain involved in the regulation of food intake. This includes the hypothalamus, which is involved in appetite regulation, and the mesolimbic dopamine circuit, which is involved in reward pathways. Studies have shown that the combined activity of bupropion and naltrexone increase the firing rate of hypothalamic pro-opiomelanocortin (POMC) neurons and blockade of opioid receptor-mediated POMC auto-inhibition, which are associated with a reduction in food intake and increased energy expenditure. This combination was also found to reduce food intake when injected directly into the ventral tegmental area of the mesolimbic circuit in mice, which is an area associated with the regulation of reward pathways. •Mechanism of action (Drug B): Nebivolol is a highly selective beta-1 adrenergic receptor antagonist with weak beta-2 adrenergic receptor antagonist activity. Blocking beta-1 adrenergic receptors by d-nebivolol leads to decreased resting heart rate, exercise heart rate, myocardial contracility, systolic blood pressure, and diastolic blood pressure. The selectivity of d-nebivolol limits the magnitude of beta blocker adverse effects in the airways or relating to insulin sensitivity. Nebivolol also inhibits aldosterone, and beta-1 antagonism in the juxtaglomerular apparatus also inhibits the release of renin. Decreased aldosterone leads to decreased blood volume, and decreased renin leads to reduced vasoconstriction. l-nebivolol is responsible for beta-3 adrenergic receptor agonist activity that stimulates endothelial nitric oxide synthase, increasing nitric oxide levels; leading to vasodilation, decreased peripheral vascular resistance, increased stroke volume, ejection fraction, and cardiac output. The vasodilation, reduced oxidative stress, and reduced platelet volume and aggregation of nebivolol may lead to benefits in heart failure patients. •Absorption (Drug A): Bupropion is currently available in 3 distinct, but bioequivalent formulations: immediate release (IR), sustained-release (SR), and extended-release (XL). Immediate Release Formulation In humans, following oral administration of bupropion hydrochloride tablets, peak plasma bupropion concentrations are usually achieved within 2 hours. IR formulations provide a short duration of action and are therefore generally dosed three times per day. Sustained Release Formulation In humans, following oral administration of bupropion hydrochloride sustained-release tablets (SR), peak plasma concentration (Cmax) of bupropion is usually achieved within 3 hours. SR formulations provide a 12-hour extended release of medication and are therefore generally dosed twice per day. Extended Release Formulation Following single oral administration of bupropion hydrochloride extended-release tablets (XL) to healthy volunteers, the median time to peak plasma concentrations for bupropion was approximately 5 hours. The presence of food did not affect the peak concentration or area under the curve of bupropion. XL formulations provide a 24-hour extended release of medication and are therefore generally dosed once per day/ In a trial comparing chronic dosing with bupropion hydrochloride extended-release tablets (SR) 150 mg twice daily to bupropion immediate-release formulation 100 mg 3 times daily, the steady state Cmax for bupropion after bupropion hydrochloride sustained-release tablets (SR) administration was approximately 85% of those achieved after bupropion immediate-release formulation administration. Exposure (AUC) to bupropion was equivalent for both formulations. Bioequivalence was also demonstrated for all three major active metabolites (i.e., hydroxybupropion, threohydrobupropion and erythrohydrobupropion) for both Cmax and AUC. Thus, at steady state, bupropion hydrochloride sustained-release tablets (SR) given twice daily, and the immediate-release formulation of bupropion given 3 times daily, are essentially bioequivalent for both bupropion and the 3 quantitatively important metabolites. Furthermore, in a study comparing 14-day dosing with bupropion hydrochloride extended-release tablets (XL), 300 mg once-daily to the immediate-release formulation of bupropion at 100 mg 3 times daily, equivalence was demonstrated for peak plasma concentration and area under the curve for bupropion and the three metabolites (hydroxybupropion, threohydrobupropion, and erythrohydrobupropion). Additionally, in a study comparing 14-day dosing with bupropion hydrochloride extended-release tablets (XL) 300 mg once daily to the sustained-release formulation of bupropion at 150 mg 2 times daily, equivalence was demonstrated for peak plasma concentration and area under the curve for bupropion and the three metabolites. Bupropion hydrochloride extended-release tablets (SR) can be taken with or without food. Bupropion Cmax and AUC were increased by 11% to 35% and 16% to 19%, respectively, when bupropion hydrochloride extended-release tablets (SR) was administered with food to healthy volunteers in three trials. The food effect is not considered clinically significant. Following a single-dose administration of bupropion hydrochloride extended-release tablets (SR) in humans, Cmax of bupropion's metabolite hydroxybupropion occurs approximately 6 hours post-dose and is approximately 10 times the peak level of the parent drug at steady state. The elimination half-life of hydroxybupropion is approximately 20 (±5) hours and its AUC at steady state is about 17 times that of bupropion. The times to peak concentrations for the erythrohydrobupropion and threohydrobupropion metabolites are similar to that of the hydroxybupropion metabolite. However, their elimination half-lives are longer, 33(±10) and 37 (±13) hours, respectively, and steady-state AUCs are 1.5 and 7 times that of bupropion, respectively. •Absorption (Drug B): The absorption of nebivolol is not affected by food. Nebivolol has a T max of 1.5-4 hours. Bioavailability can range from 12-96% for extensive to poor CYP2D6 metabolizers. For a 20mg dose, d-nebivolol has a C max of 2.75±1.55ng/mL, l-nebivolol has a C max of 5.29±2.06ng/mL, both enantiomers have a C max of 8.02±3.47ng/mL, and nebivolol glucuronides have a C max of 68.34±44.68ng/mL. For a 20mg dose, d-nebivolol has an AUC of 13.78±15.27ng*h/mL, l-nebivolol has an AUC of 27.72±15.32ng*h/mL, both enantiomers have an AUC of 41.50±29.76ng*h/mL, and nebivolol glucuronides have an AUC of 396.78±297.94ng*h/mL. •Volume of distribution (Drug A): No volume of distribution available •Volume of distribution (Drug B): For a 20mg dose, d-nebivolol has an apparent volume of distribution of 10,290.81±3911.72L, l-nebivolol has an apparent volume of distribution of 8,066.66±4,055.50L, and both enantiomers together have a volume of distribution of 10,423.42±6796.50L. •Protein binding (Drug A): In vitro tests show that bupropion is 84% bound to human plasma proteins at concentrations up to 200 mcg per mL. The extent of protein binding of the hydroxybupropion metabolite is similar to that for bupropion, whereas the extent of protein binding of the threohydrobupropion metabolite is about half that seen with bupropion. •Protein binding (Drug B): Nebivolol is 98% bound to plasma proteins, mostly to serum albumin. •Metabolism (Drug A): Bupropion is extensively metabolized in humans. Three metabolites are active: hydroxybupropion, which is formed via hydroxylation of the tert-butyl group of bupropion, and the amino-alcohol isomers, threohydrobupropion and erythrohydrobupropion, which are formed via reduction of the carbonyl group. In vitro findings suggest that CYP2B6 is the principal isoenzyme involved in the formation of hydroxybupropion, while cytochrome P450 enzymes are not involved in the formation of threohydrobupropion. Hydroxybupropion has been shown to have the same affinity as bupropion for the norepinephrine transporter (NET) but approximately 50% of its antidepressant activity despite reaching concentrations of ~10-fold higher than that of the parent drug. Oxidation of the bupropion side chain results in the formation of a glycine conjugate of meta-chlorobenzoic acid, which is then excreted as the major urinary metabolite. The potency and toxicity of the metabolites relative to bupropion have not been fully characterized. However, it has been demonstrated in an antidepressant screening test in mice that hydroxybupropion is one-half as potent as bupropion, while threohydrobupropion and erythrohydrobupropion are 5-fold less potent than bupropion. This may be of clinical importance because the plasma concentrations of the metabolites are as high as or higher than those of bupropion. Bupropion and its metabolites exhibit linear kinetics following chronic administration of 300 to 450 mg per day. •Metabolism (Drug B): Nebivolol is metabolized mainly by glucuronidation and CYP2D6 mediated hydroxylation. Metabolism involves n-dealkylation, hydroxylation, oxidation, and glucuronidation. Aromatic hydroxyl and acyclic oxide metabolites are active, while n-dealkylated and glucuronides are inactive. •Route of elimination (Drug A): Bupropion is extensively metabolized in humans. Oxidation of the bupropion side chain results in the formation of a glycine conjugate of metachlorobenzoic acid, which is then excreted as the major urinary metabolite. Following oral administration of 200 mg of 14C-bupropion in humans, 87% and 10% of the radioactive dose were recovered in the urine and feces, respectively. However, the fraction of the oral dose of bupropion excreted unchanged was only 0.5%, a finding consistent with the extensive metabolism of bupropion. •Route of elimination (Drug B): In extensive CYP2D6 metabolizers, 38% is eliminated in the urine and 44% in the feces. In poor CYP2D6 metabolizers, 67% is eliminated in the urine and 13% in the feces. <1% of a dose is excreted as the unmetabolized drug. •Half-life (Drug A): 24 hours •Half-life (Drug B): d-nebivolol has a half life of 12 hours in CYP2D6 extensive metabolizers and 19 hours in poor metabolizers. •Clearance (Drug A): No clearance available •Clearance (Drug B): For a 20mg dose, the clearance of d-nebivolol is 1241.63±749.77L/h, l-nebivolol is 435.53±180.93L/h, and both enantiomers is 635.31±300.25L/h. •Toxicity (Drug A): Symptoms of overdose include seizures, hallucinations, loss of consciousness, tachycardia, and cardiac arrest. •Toxicity (Drug B): Patients experiencing an overdose may present with bradycardia, hypotension, cardiac failure, dizziness, hypoglycemia, fatigue, vomiting, bronchospasm and heart block. Treat overdose with general supportive measures including intravenous atropine for bradycardia, vasopressors and intravenous fluids for hypotension, isoproterenol infusion for heart block, digitalis glycosides and diuretics for congestive heart failure, bronchodilators for bronchospasm, and intravenous glucose for hypoglycemia. •Brand Names (Drug A): Aplenzin, Auvelity, Budeprion, Contrave, Forfivo, Wellbutrin, Zyban •Brand Names (Drug B): Bystolic •Synonyms (Drug A): No synonyms listed •Synonyms (Drug B): No synonyms listed •Summary (Drug A): Bupropion is a norepinephrine and dopamine reuptake inhibitor used in the treatment of major depressive disorder (MDD), seasonal affective disorder (SAD), and as an aid to smoking cessation. •Summary (Drug B): Nebivolol is a beta blocking agent used to treat hypertension and aid in the management of heart failure.

The subject drug is a strong CYP2D6 inhibitor and the affected drug is metabolized by CYP2D6. Concomitant administration may decrease the metabolism of the affected drug, which could increase serum concentrations as well as the risk and severity of adverse effects. The severity of the interaction is major.

Question: Does Bupropion and Nebivolol interact? Information: •Drug A: Bupropion •Drug B: Nebivolol •Severity: MAJOR •Description: The metabolism of Nebivolol can be decreased when combined with Bupropion. •Extended Description: The subject drug is a strong CYP2D6 inhibitor and the affected drug is metabolized by CYP2D6. Concomitant administration may decrease the metabolism of the affected drug, which could increase serum concentrations as well as the risk and severity of adverse effects. •Indication (Drug A): Bupropion is indicated for the treatment of major depressive disorder (MDD), seasonal affective disorder (SAD), and as an aid to smoking cessation. When used in combination with naltrexone as the marketed product ContraveⓇ, bupropion is indicated as an adjunct to a reduced-calorie diet and increased physical activity for chronic weight management in adults with an initial body mass index (BMI) of: 30 kg/m^2 or greater (obese) or 27 kg/m^2 or greater (overweight) in the presence of at least one weight-related comorbid condition (e.g., hypertension, type 2 diabetes mellitus, or dyslipidemia). Bupropion is also used off-label as a first-line treatment in patients with ADHD and comorbid bipolar disorder when used as an adjunct to mood stabilizers. •Indication (Drug B): Nebivolol is indicated to treat hypertension. •Pharmacodynamics (Drug A): Bupropion is chemically unrelated to tricyclic, tetracyclic, selective serotonin re-uptake inhibitors, or other known antidepressant agents. Compared to classical tricyclic antidepressants, Bupropion is a relatively weak inhibitor of the neuronal uptake of norepinephrine and dopamine. In addition, Bupropion does not inhibit monoamine oxidase. Bupropion has been found to be essentially inactive at the serotonin transporter (SERT)(IC50 >10 000 nM), however both bupropion and its primary metabolite hydroxybupropion have been found to block the function of cation-selective serotonin type 3A receptors (5-HT3ARs). Bupropion produces dose-related central nervous system (CNS) stimulant effects in animals, as evidenced by increased locomotor activity, increased rates of responding in various schedule-controlled operant behaviour tasks, and, at high doses, induction of mild stereotyped behaviour. Due to these stimulant effects and selective activity at dopamine and norepinephrine receptors, bupropion has been identified as having an abuse potential. Bupropion has a similar structure to the controlled substance Cathinone, and has been identified as having mild amphetamine-like activity, particularly when inhaled or injected. Bupropion is also known to lower the seizure threshold, making any pre-existing seizure conditions a contraindication to its use. This risk is exacerbated when bupropion is combined with other drugs or substances that lower the seizure threshold, such as cocaine, or in clinical situations that would increase the risk of a seizure such as abrupt alcohol or benzodiazepine withdrawal. As norepinephrine has been shown to have anticonvulsant properties, bupropion's inhibitory effects on NET are thought to contribute to its pro-convulsant activity. Bupropion has been shown to increase blood pressure and pose a risk for exacerbation of unmanaged or pre-existing hypertension, however, clinical trials of bupropion in smokers with CVD have not identified an increased incidence of CV events including stroke or heart attack. In clinical trials, the mean increase in systolic blood pressure associated with the use of bupropion was found to be 1.3 mmHg. •Pharmacodynamics (Drug B): Nebivolol is a selective beta-1 adrenergic receptor antagonist that decreases vascular resistance, increases stroke volume and cardiac output, and does not negatively affect left ventricular function. It has a long duration of action as effects can be seen 48 hours after stopping the medication and a wide therapeutic window as patients generally take 5-40mg daily. Patients should not abruptly stop taking this medication as this may lead to exacerbation of coronary artery disease. Diabetic patients should monitor their blood glucose levels as beta blockers may mask signs of hypoglycemia. •Mechanism of action (Drug A): Bupropion is a norepinephrine/dopamine-reuptake inhibitor (NDRI) that exerts its pharmacological effects by weakly inhibiting the enzymes involved in the uptake of the neurotransmitters norepinephrine and dopamine from the synaptic cleft, therefore prolonging their duration of action within the neuronal synapse and the downstream effects of these neurotransmitters. More specifically, bupropion binds to the norepinephrine transporter (NET) and the dopamine transporter (DAT). Bupropion was originally classified as an "atypical" antidepressant because it does not exert the same effects as the classical antidepressants such as Monoamine Oxidase Inhibitors (MAOIs), Tricyclic Antidepressants (TCAs), or Selective Serotonin Reuptake Inhibitors (SSRIs). While it has comparable effectiveness to typical first-line options for the treatment of depression such as SSRIs, bupropion is a unique option for the treatment of MDD as it lacks any clinically relevant serotonergic effects, typical of other mood medications, or any effects on histamine or adrenaline receptors. Lack of activity at these receptors results in a more tolerable side effect profile; bupropion is less likely to cause sexual side effects, sedation, or weight gain as compared to SSRIs or TCAs, for example. When used as an aid to smoking cessation, bupropion is thought to confer its anti-craving and anti-withdrawal effects by inhibiting dopamine reuptake, which is thought to be involved in the reward pathways associated with nicotine, and through the antagonism of the nicotinic acetylcholinergic receptor (AChR), thereby blunting the effects of nicotine. Furthermore, the stimulatory effects produced by bupropion in the central nervous system are similar to nicotine's effects, making low doses of bupropion a suitable option as a nicotine substitute. When used in combination with naltrexone in the marketed product ContraveⓇ for chronic weight management, the two components are thought to have effects on areas of the brain involved in the regulation of food intake. This includes the hypothalamus, which is involved in appetite regulation, and the mesolimbic dopamine circuit, which is involved in reward pathways. Studies have shown that the combined activity of bupropion and naltrexone increase the firing rate of hypothalamic pro-opiomelanocortin (POMC) neurons and blockade of opioid receptor-mediated POMC auto-inhibition, which are associated with a reduction in food intake and increased energy expenditure. This combination was also found to reduce food intake when injected directly into the ventral tegmental area of the mesolimbic circuit in mice, which is an area associated with the regulation of reward pathways. •Mechanism of action (Drug B): Nebivolol is a highly selective beta-1 adrenergic receptor antagonist with weak beta-2 adrenergic receptor antagonist activity. Blocking beta-1 adrenergic receptors by d-nebivolol leads to decreased resting heart rate, exercise heart rate, myocardial contracility, systolic blood pressure, and diastolic blood pressure. The selectivity of d-nebivolol limits the magnitude of beta blocker adverse effects in the airways or relating to insulin sensitivity. Nebivolol also inhibits aldosterone, and beta-1 antagonism in the juxtaglomerular apparatus also inhibits the release of renin. Decreased aldosterone leads to decreased blood volume, and decreased renin leads to reduced vasoconstriction. l-nebivolol is responsible for beta-3 adrenergic receptor agonist activity that stimulates endothelial nitric oxide synthase, increasing nitric oxide levels; leading to vasodilation, decreased peripheral vascular resistance, increased stroke volume, ejection fraction, and cardiac output. The vasodilation, reduced oxidative stress, and reduced platelet volume and aggregation of nebivolol may lead to benefits in heart failure patients. •Absorption (Drug A): Bupropion is currently available in 3 distinct, but bioequivalent formulations: immediate release (IR), sustained-release (SR), and extended-release (XL). Immediate Release Formulation In humans, following oral administration of bupropion hydrochloride tablets, peak plasma bupropion concentrations are usually achieved within 2 hours. IR formulations provide a short duration of action and are therefore generally dosed three times per day. Sustained Release Formulation In humans, following oral administration of bupropion hydrochloride sustained-release tablets (SR), peak plasma concentration (Cmax) of bupropion is usually achieved within 3 hours. SR formulations provide a 12-hour extended release of medication and are therefore generally dosed twice per day. Extended Release Formulation Following single oral administration of bupropion hydrochloride extended-release tablets (XL) to healthy volunteers, the median time to peak plasma concentrations for bupropion was approximately 5 hours. The presence of food did not affect the peak concentration or area under the curve of bupropion. XL formulations provide a 24-hour extended release of medication and are therefore generally dosed once per day/ In a trial comparing chronic dosing with bupropion hydrochloride extended-release tablets (SR) 150 mg twice daily to bupropion immediate-release formulation 100 mg 3 times daily, the steady state Cmax for bupropion after bupropion hydrochloride sustained-release tablets (SR) administration was approximately 85% of those achieved after bupropion immediate-release formulation administration. Exposure (AUC) to bupropion was equivalent for both formulations. Bioequivalence was also demonstrated for all three major active metabolites (i.e., hydroxybupropion, threohydrobupropion and erythrohydrobupropion) for both Cmax and AUC. Thus, at steady state, bupropion hydrochloride sustained-release tablets (SR) given twice daily, and the immediate-release formulation of bupropion given 3 times daily, are essentially bioequivalent for both bupropion and the 3 quantitatively important metabolites. Furthermore, in a study comparing 14-day dosing with bupropion hydrochloride extended-release tablets (XL), 300 mg once-daily to the immediate-release formulation of bupropion at 100 mg 3 times daily, equivalence was demonstrated for peak plasma concentration and area under the curve for bupropion and the three metabolites (hydroxybupropion, threohydrobupropion, and erythrohydrobupropion). Additionally, in a study comparing 14-day dosing with bupropion hydrochloride extended-release tablets (XL) 300 mg once daily to the sustained-release formulation of bupropion at 150 mg 2 times daily, equivalence was demonstrated for peak plasma concentration and area under the curve for bupropion and the three metabolites. Bupropion hydrochloride extended-release tablets (SR) can be taken with or without food. Bupropion Cmax and AUC were increased by 11% to 35% and 16% to 19%, respectively, when bupropion hydrochloride extended-release tablets (SR) was administered with food to healthy volunteers in three trials. The food effect is not considered clinically significant. Following a single-dose administration of bupropion hydrochloride extended-release tablets (SR) in humans, Cmax of bupropion's metabolite hydroxybupropion occurs approximately 6 hours post-dose and is approximately 10 times the peak level of the parent drug at steady state. The elimination half-life of hydroxybupropion is approximately 20 (±5) hours and its AUC at steady state is about 17 times that of bupropion. The times to peak concentrations for the erythrohydrobupropion and threohydrobupropion metabolites are similar to that of the hydroxybupropion metabolite. However, their elimination half-lives are longer, 33(±10) and 37 (±13) hours, respectively, and steady-state AUCs are 1.5 and 7 times that of bupropion, respectively. •Absorption (Drug B): The absorption of nebivolol is not affected by food. Nebivolol has a T max of 1.5-4 hours. Bioavailability can range from 12-96% for extensive to poor CYP2D6 metabolizers. For a 20mg dose, d-nebivolol has a C max of 2.75±1.55ng/mL, l-nebivolol has a C max of 5.29±2.06ng/mL, both enantiomers have a C max of 8.02±3.47ng/mL, and nebivolol glucuronides have a C max of 68.34±44.68ng/mL. For a 20mg dose, d-nebivolol has an AUC of 13.78±15.27ng*h/mL, l-nebivolol has an AUC of 27.72±15.32ng*h/mL, both enantiomers have an AUC of 41.50±29.76ng*h/mL, and nebivolol glucuronides have an AUC of 396.78±297.94ng*h/mL. •Volume of distribution (Drug A): No volume of distribution available •Volume of distribution (Drug B): For a 20mg dose, d-nebivolol has an apparent volume of distribution of 10,290.81±3911.72L, l-nebivolol has an apparent volume of distribution of 8,066.66±4,055.50L, and both enantiomers together have a volume of distribution of 10,423.42±6796.50L. •Protein binding (Drug A): In vitro tests show that bupropion is 84% bound to human plasma proteins at concentrations up to 200 mcg per mL. The extent of protein binding of the hydroxybupropion metabolite is similar to that for bupropion, whereas the extent of protein binding of the threohydrobupropion metabolite is about half that seen with bupropion. •Protein binding (Drug B): Nebivolol is 98% bound to plasma proteins, mostly to serum albumin. •Metabolism (Drug A): Bupropion is extensively metabolized in humans. Three metabolites are active: hydroxybupropion, which is formed via hydroxylation of the tert-butyl group of bupropion, and the amino-alcohol isomers, threohydrobupropion and erythrohydrobupropion, which are formed via reduction of the carbonyl group. In vitro findings suggest that CYP2B6 is the principal isoenzyme involved in the formation of hydroxybupropion, while cytochrome P450 enzymes are not involved in the formation of threohydrobupropion. Hydroxybupropion has been shown to have the same affinity as bupropion for the norepinephrine transporter (NET) but approximately 50% of its antidepressant activity despite reaching concentrations of ~10-fold higher than that of the parent drug. Oxidation of the bupropion side chain results in the formation of a glycine conjugate of meta-chlorobenzoic acid, which is then excreted as the major urinary metabolite. The potency and toxicity of the metabolites relative to bupropion have not been fully characterized. However, it has been demonstrated in an antidepressant screening test in mice that hydroxybupropion is one-half as potent as bupropion, while threohydrobupropion and erythrohydrobupropion are 5-fold less potent than bupropion. This may be of clinical importance because the plasma concentrations of the metabolites are as high as or higher than those of bupropion. Bupropion and its metabolites exhibit linear kinetics following chronic administration of 300 to 450 mg per day. •Metabolism (Drug B): Nebivolol is metabolized mainly by glucuronidation and CYP2D6 mediated hydroxylation. Metabolism involves n-dealkylation, hydroxylation, oxidation, and glucuronidation. Aromatic hydroxyl and acyclic oxide metabolites are active, while n-dealkylated and glucuronides are inactive. •Route of elimination (Drug A): Bupropion is extensively metabolized in humans. Oxidation of the bupropion side chain results in the formation of a glycine conjugate of metachlorobenzoic acid, which is then excreted as the major urinary metabolite. Following oral administration of 200 mg of 14C-bupropion in humans, 87% and 10% of the radioactive dose were recovered in the urine and feces, respectively. However, the fraction of the oral dose of bupropion excreted unchanged was only 0.5%, a finding consistent with the extensive metabolism of bupropion. •Route of elimination (Drug B): In extensive CYP2D6 metabolizers, 38% is eliminated in the urine and 44% in the feces. In poor CYP2D6 metabolizers, 67% is eliminated in the urine and 13% in the feces. <1% of a dose is excreted as the unmetabolized drug. •Half-life (Drug A): 24 hours •Half-life (Drug B): d-nebivolol has a half life of 12 hours in CYP2D6 extensive metabolizers and 19 hours in poor metabolizers. •Clearance (Drug A): No clearance available •Clearance (Drug B): For a 20mg dose, the clearance of d-nebivolol is 1241.63±749.77L/h, l-nebivolol is 435.53±180.93L/h, and both enantiomers is 635.31±300.25L/h. •Toxicity (Drug A): Symptoms of overdose include seizures, hallucinations, loss of consciousness, tachycardia, and cardiac arrest. •Toxicity (Drug B): Patients experiencing an overdose may present with bradycardia, hypotension, cardiac failure, dizziness, hypoglycemia, fatigue, vomiting, bronchospasm and heart block. Treat overdose with general supportive measures including intravenous atropine for bradycardia, vasopressors and intravenous fluids for hypotension, isoproterenol infusion for heart block, digitalis glycosides and diuretics for congestive heart failure, bronchodilators for bronchospasm, and intravenous glucose for hypoglycemia. •Brand Names (Drug A): Aplenzin, Auvelity, Budeprion, Contrave, Forfivo, Wellbutrin, Zyban •Brand Names (Drug B): Bystolic •Synonyms (Drug A): No synonyms listed •Synonyms (Drug B): No synonyms listed •Summary (Drug A): Bupropion is a norepinephrine and dopamine reuptake inhibitor used in the treatment of major depressive disorder (MDD), seasonal affective disorder (SAD), and as an aid to smoking cessation. •Summary (Drug B): Nebivolol is a beta blocking agent used to treat hypertension and aid in the management of heart failure. Output: The subject drug is a strong CYP2D6 inhibitor and the affected drug is metabolized by CYP2D6. Concomitant administration may decrease the metabolism of the affected drug, which could increase serum concentrations as well as the risk and severity of adverse effects. The severity of the interaction is major.

Does Bupropion and Nedocromil interact?

•Drug A: Bupropion •Drug B: Nedocromil •Severity: MINOR •Description: Nedocromil may decrease the excretion rate of Bupropion which could result in a higher serum level. •Extended Description: The renal excretion of drugs is the overall result of a combination of kidney processes that include glomerular filtration, passive diffusion, tubular secretion, and tubular reabsorption. Since two of these mechanisms - tubular secretion and reabsorption - are saturable processes , they are consequently susceptible to competition between multiple substrates excreted by the kidneys. If two or more medications that are mainly renally excreted are co-administered, they may compete for renal elimination; there is a large likelihood that one agent may "out-compete" or saturate the renal excretion mechanisms before the other concomitantly administered agent(s) are excreted. As a result, the elimination of these other concurrently administered agents may be inhibited or otherwise delayed, which could lead to increases in their serum concentrations and the risk, incidence, and/or severity of adverse effects associated with the exposure to such drugs. •Indication (Drug A): Bupropion is indicated for the treatment of major depressive disorder (MDD), seasonal affective disorder (SAD), and as an aid to smoking cessation. When used in combination with naltrexone as the marketed product ContraveⓇ, bupropion is indicated as an adjunct to a reduced-calorie diet and increased physical activity for chronic weight management in adults with an initial body mass index (BMI) of: 30 kg/m^2 or greater (obese) or 27 kg/m^2 or greater (overweight) in the presence of at least one weight-related comorbid condition (e.g., hypertension, type 2 diabetes mellitus, or dyslipidemia). Bupropion is also used off-label as a first-line treatment in patients with ADHD and comorbid bipolar disorder when used as an adjunct to mood stabilizers. •Indication (Drug B): For the treatment of mild to moderate asthma •Pharmacodynamics (Drug A): Bupropion is chemically unrelated to tricyclic, tetracyclic, selective serotonin re-uptake inhibitors, or other known antidepressant agents. Compared to classical tricyclic antidepressants, Bupropion is a relatively weak inhibitor of the neuronal uptake of norepinephrine and dopamine. In addition, Bupropion does not inhibit monoamine oxidase. Bupropion has been found to be essentially inactive at the serotonin transporter (SERT)(IC50 >10 000 nM), however both bupropion and its primary metabolite hydroxybupropion have been found to block the function of cation-selective serotonin type 3A receptors (5-HT3ARs). Bupropion produces dose-related central nervous system (CNS) stimulant effects in animals, as evidenced by increased locomotor activity, increased rates of responding in various schedule-controlled operant behaviour tasks, and, at high doses, induction of mild stereotyped behaviour. Due to these stimulant effects and selective activity at dopamine and norepinephrine receptors, bupropion has been identified as having an abuse potential. Bupropion has a similar structure to the controlled substance Cathinone, and has been identified as having mild amphetamine-like activity, particularly when inhaled or injected. Bupropion is also known to lower the seizure threshold, making any pre-existing seizure conditions a contraindication to its use. This risk is exacerbated when bupropion is combined with other drugs or substances that lower the seizure threshold, such as cocaine, or in clinical situations that would increase the risk of a seizure such as abrupt alcohol or benzodiazepine withdrawal. As norepinephrine has been shown to have anticonvulsant properties, bupropion's inhibitory effects on NET are thought to contribute to its pro-convulsant activity. Bupropion has been shown to increase blood pressure and pose a risk for exacerbation of unmanaged or pre-existing hypertension, however, clinical trials of bupropion in smokers with CVD have not identified an increased incidence of CV events including stroke or heart attack. In clinical trials, the mean increase in systolic blood pressure associated with the use of bupropion was found to be 1.3 mmHg. •Pharmacodynamics (Drug B): Nedocromil is a anti-inflammatory agent and can be administered directly to the bronchial mucosa. It has significant inhibitory effect on allergen-induced early and late asthmatic reactions and on bronchial hyperresponsiveness. •Mechanism of action (Drug A): Bupropion is a norepinephrine/dopamine-reuptake inhibitor (NDRI) that exerts its pharmacological effects by weakly inhibiting the enzymes involved in the uptake of the neurotransmitters norepinephrine and dopamine from the synaptic cleft, therefore prolonging their duration of action within the neuronal synapse and the downstream effects of these neurotransmitters. More specifically, bupropion binds to the norepinephrine transporter (NET) and the dopamine transporter (DAT). Bupropion was originally classified as an "atypical" antidepressant because it does not exert the same effects as the classical antidepressants such as Monoamine Oxidase Inhibitors (MAOIs), Tricyclic Antidepressants (TCAs), or Selective Serotonin Reuptake Inhibitors (SSRIs). While it has comparable effectiveness to typical first-line options for the treatment of depression such as SSRIs, bupropion is a unique option for the treatment of MDD as it lacks any clinically relevant serotonergic effects, typical of other mood medications, or any effects on histamine or adrenaline receptors. Lack of activity at these receptors results in a more tolerable side effect profile; bupropion is less likely to cause sexual side effects, sedation, or weight gain as compared to SSRIs or TCAs, for example. When used as an aid to smoking cessation, bupropion is thought to confer its anti-craving and anti-withdrawal effects by inhibiting dopamine reuptake, which is thought to be involved in the reward pathways associated with nicotine, and through the antagonism of the nicotinic acetylcholinergic receptor (AChR), thereby blunting the effects of nicotine. Furthermore, the stimulatory effects produced by bupropion in the central nervous system are similar to nicotine's effects, making low doses of bupropion a suitable option as a nicotine substitute. When used in combination with naltrexone in the marketed product ContraveⓇ for chronic weight management, the two components are thought to have effects on areas of the brain involved in the regulation of food intake. This includes the hypothalamus, which is involved in appetite regulation, and the mesolimbic dopamine circuit, which is involved in reward pathways. Studies have shown that the combined activity of bupropion and naltrexone increase the firing rate of hypothalamic pro-opiomelanocortin (POMC) neurons and blockade of opioid receptor-mediated POMC auto-inhibition, which are associated with a reduction in food intake and increased energy expenditure. This combination was also found to reduce food intake when injected directly into the ventral tegmental area of the mesolimbic circuit in mice, which is an area associated with the regulation of reward pathways. •Mechanism of action (Drug B): Nedocromil has been shown to inhibit the in vitro activation of, and mediator release from, a variety of inflammatory cell types associated with asthma, including eosinophils, neutrophils, macrophages, mast cells, monocytes, and platelets. Nedocromil inhibits activation and release of inflammatory mediators such as histamine, prostaglandin D2 and leukotrienes c4 from different types of cells in the lumen and mucosa of the bronchial tree. These mediators are derived from arachidonic acid metabolism through the lipoxygenase and cyclo-oxygenase pathways. The mechanism of action of nedocromil may be due partly to inhibition of axon reflexes and release of sensory neuropeptides, such as substance P, neurokinin A, and calcitonin-geneñrelated peptides. The result is inhibition of bradykinin-induced bronchoconstriction. Nedocromil does not posess any bronchodilator, antihistamine, or corticosteroid activity. •Absorption (Drug A): Bupropion is currently available in 3 distinct, but bioequivalent formulations: immediate release (IR), sustained-release (SR), and extended-release (XL). Immediate Release Formulation In humans, following oral administration of bupropion hydrochloride tablets, peak plasma bupropion concentrations are usually achieved within 2 hours. IR formulations provide a short duration of action and are therefore generally dosed three times per day. Sustained Release Formulation In humans, following oral administration of bupropion hydrochloride sustained-release tablets (SR), peak plasma concentration (Cmax) of bupropion is usually achieved within 3 hours. SR formulations provide a 12-hour extended release of medication and are therefore generally dosed twice per day. Extended Release Formulation Following single oral administration of bupropion hydrochloride extended-release tablets (XL) to healthy volunteers, the median time to peak plasma concentrations for bupropion was approximately 5 hours. The presence of food did not affect the peak concentration or area under the curve of bupropion. XL formulations provide a 24-hour extended release of medication and are therefore generally dosed once per day/ In a trial comparing chronic dosing with bupropion hydrochloride extended-release tablets (SR) 150 mg twice daily to bupropion immediate-release formulation 100 mg 3 times daily, the steady state Cmax for bupropion after bupropion hydrochloride sustained-release tablets (SR) administration was approximately 85% of those achieved after bupropion immediate-release formulation administration. Exposure (AUC) to bupropion was equivalent for both formulations. Bioequivalence was also demonstrated for all three major active metabolites (i.e., hydroxybupropion, threohydrobupropion and erythrohydrobupropion) for both Cmax and AUC. Thus, at steady state, bupropion hydrochloride sustained-release tablets (SR) given twice daily, and the immediate-release formulation of bupropion given 3 times daily, are essentially bioequivalent for both bupropion and the 3 quantitatively important metabolites. Furthermore, in a study comparing 14-day dosing with bupropion hydrochloride extended-release tablets (XL), 300 mg once-daily to the immediate-release formulation of bupropion at 100 mg 3 times daily, equivalence was demonstrated for peak plasma concentration and area under the curve for bupropion and the three metabolites (hydroxybupropion, threohydrobupropion, and erythrohydrobupropion). Additionally, in a study comparing 14-day dosing with bupropion hydrochloride extended-release tablets (XL) 300 mg once daily to the sustained-release formulation of bupropion at 150 mg 2 times daily, equivalence was demonstrated for peak plasma concentration and area under the curve for bupropion and the three metabolites. Bupropion hydrochloride extended-release tablets (SR) can be taken with or without food. Bupropion Cmax and AUC were increased by 11% to 35% and 16% to 19%, respectively, when bupropion hydrochloride extended-release tablets (SR) was administered with food to healthy volunteers in three trials. The food effect is not considered clinically significant. Following a single-dose administration of bupropion hydrochloride extended-release tablets (SR) in humans, Cmax of bupropion's metabolite hydroxybupropion occurs approximately 6 hours post-dose and is approximately 10 times the peak level of the parent drug at steady state. The elimination half-life of hydroxybupropion is approximately 20 (±5) hours and its AUC at steady state is about 17 times that of bupropion. The times to peak concentrations for the erythrohydrobupropion and threohydrobupropion metabolites are similar to that of the hydroxybupropion metabolite. However, their elimination half-lives are longer, 33(±10) and 37 (±13) hours, respectively, and steady-state AUCs are 1.5 and 7 times that of bupropion, respectively. •Absorption (Drug B): Low •Volume of distribution (Drug A): No volume of distribution available •Volume of distribution (Drug B): No volume of distribution available •Protein binding (Drug A): In vitro tests show that bupropion is 84% bound to human plasma proteins at concentrations up to 200 mcg per mL. The extent of protein binding of the hydroxybupropion metabolite is similar to that for bupropion, whereas the extent of protein binding of the threohydrobupropion metabolite is about half that seen with bupropion. •Protein binding (Drug B): approximately 89% protein bound in human plasma over a concentration range of 0.5 to 50 µg/mL •Metabolism (Drug A): Bupropion is extensively metabolized in humans. Three metabolites are active: hydroxybupropion, which is formed via hydroxylation of the tert-butyl group of bupropion, and the amino-alcohol isomers, threohydrobupropion and erythrohydrobupropion, which are formed via reduction of the carbonyl group. In vitro findings suggest that CYP2B6 is the principal isoenzyme involved in the formation of hydroxybupropion, while cytochrome P450 enzymes are not involved in the formation of threohydrobupropion. Hydroxybupropion has been shown to have the same affinity as bupropion for the norepinephrine transporter (NET) but approximately 50% of its antidepressant activity despite reaching concentrations of ~10-fold higher than that of the parent drug. Oxidation of the bupropion side chain results in the formation of a glycine conjugate of meta-chlorobenzoic acid, which is then excreted as the major urinary metabolite. The potency and toxicity of the metabolites relative to bupropion have not been fully characterized. However, it has been demonstrated in an antidepressant screening test in mice that hydroxybupropion is one-half as potent as bupropion, while threohydrobupropion and erythrohydrobupropion are 5-fold less potent than bupropion. This may be of clinical importance because the plasma concentrations of the metabolites are as high as or higher than those of bupropion. Bupropion and its metabolites exhibit linear kinetics following chronic administration of 300 to 450 mg per day. •Metabolism (Drug B): Nedocromil is not metabolized after IV administration and is excreted unchanged. •Route of elimination (Drug A): Bupropion is extensively metabolized in humans. Oxidation of the bupropion side chain results in the formation of a glycine conjugate of metachlorobenzoic acid, which is then excreted as the major urinary metabolite. Following oral administration of 200 mg of 14C-bupropion in humans, 87% and 10% of the radioactive dose were recovered in the urine and feces, respectively. However, the fraction of the oral dose of bupropion excreted unchanged was only 0.5%, a finding consistent with the extensive metabolism of bupropion. •Route of elimination (Drug B): It is not metabolized and is eliminated primarily unchanged in urine (70%) and feces (30%). •Half-life (Drug A): 24 hours •Half-life (Drug B): ~3.3 hours •Clearance (Drug A): No clearance available •Clearance (Drug B): No clearance available •Toxicity (Drug A): Symptoms of overdose include seizures, hallucinations, loss of consciousness, tachycardia, and cardiac arrest. •Toxicity (Drug B): Side effects include headache, nasal congestion, ocular burning, irritation and stinging, unpleasant taste, cough, difficulty breathing, noisy breathing, shortness of breath, tightness in chest, wheezing, conjunctivitis, blurred vision, change in color vision, difficulty seeing at night, increased sensitivity of eyes to sunlight. •Brand Names (Drug A): Aplenzin, Auvelity, Budeprion, Contrave, Forfivo, Wellbutrin, Zyban •Brand Names (Drug B): Alocril •Synonyms (Drug A): No synonyms listed •Synonyms (Drug B): Nedocromil Nédocromil Nedocromilo Nedocromilum •Summary (Drug A): Bupropion is a norepinephrine and dopamine reuptake inhibitor used in the treatment of major depressive disorder (MDD), seasonal affective disorder (SAD), and as an aid to smoking cessation. •Summary (Drug B): Nedocromil is a pyrano quinoline used to treat allergic conjunctivitis.

The renal excretion of drugs is the overall result of a combination of kidney processes that include glomerular filtration, passive diffusion, tubular secretion, and tubular reabsorption. Since two of these mechanisms - tubular secretion and reabsorption - are saturable processes , they are consequently susceptible to competition between multiple substrates excreted by the kidneys. If two or more medications that are mainly renally excreted are co-administered, they may compete for renal elimination; there is a large likelihood that one agent may "out-compete" or saturate the renal excretion mechanisms before the other concomitantly administered agent(s) are excreted. As a result, the elimination of these other concurrently administered agents may be inhibited or otherwise delayed, which could lead to increases in their serum concentrations and the risk, incidence, and/or severity of adverse effects associated with the exposure to such drugs. The severity of the interaction is minor.

Question: Does Bupropion and Nedocromil interact? Information: •Drug A: Bupropion •Drug B: Nedocromil •Severity: MINOR •Description: Nedocromil may decrease the excretion rate of Bupropion which could result in a higher serum level. •Extended Description: The renal excretion of drugs is the overall result of a combination of kidney processes that include glomerular filtration, passive diffusion, tubular secretion, and tubular reabsorption. Since two of these mechanisms - tubular secretion and reabsorption - are saturable processes , they are consequently susceptible to competition between multiple substrates excreted by the kidneys. If two or more medications that are mainly renally excreted are co-administered, they may compete for renal elimination; there is a large likelihood that one agent may "out-compete" or saturate the renal excretion mechanisms before the other concomitantly administered agent(s) are excreted. As a result, the elimination of these other concurrently administered agents may be inhibited or otherwise delayed, which could lead to increases in their serum concentrations and the risk, incidence, and/or severity of adverse effects associated with the exposure to such drugs. •Indication (Drug A): Bupropion is indicated for the treatment of major depressive disorder (MDD), seasonal affective disorder (SAD), and as an aid to smoking cessation. When used in combination with naltrexone as the marketed product ContraveⓇ, bupropion is indicated as an adjunct to a reduced-calorie diet and increased physical activity for chronic weight management in adults with an initial body mass index (BMI) of: 30 kg/m^2 or greater (obese) or 27 kg/m^2 or greater (overweight) in the presence of at least one weight-related comorbid condition (e.g., hypertension, type 2 diabetes mellitus, or dyslipidemia). Bupropion is also used off-label as a first-line treatment in patients with ADHD and comorbid bipolar disorder when used as an adjunct to mood stabilizers. •Indication (Drug B): For the treatment of mild to moderate asthma •Pharmacodynamics (Drug A): Bupropion is chemically unrelated to tricyclic, tetracyclic, selective serotonin re-uptake inhibitors, or other known antidepressant agents. Compared to classical tricyclic antidepressants, Bupropion is a relatively weak inhibitor of the neuronal uptake of norepinephrine and dopamine. In addition, Bupropion does not inhibit monoamine oxidase. Bupropion has been found to be essentially inactive at the serotonin transporter (SERT)(IC50 >10 000 nM), however both bupropion and its primary metabolite hydroxybupropion have been found to block the function of cation-selective serotonin type 3A receptors (5-HT3ARs). Bupropion produces dose-related central nervous system (CNS) stimulant effects in animals, as evidenced by increased locomotor activity, increased rates of responding in various schedule-controlled operant behaviour tasks, and, at high doses, induction of mild stereotyped behaviour. Due to these stimulant effects and selective activity at dopamine and norepinephrine receptors, bupropion has been identified as having an abuse potential. Bupropion has a similar structure to the controlled substance Cathinone, and has been identified as having mild amphetamine-like activity, particularly when inhaled or injected. Bupropion is also known to lower the seizure threshold, making any pre-existing seizure conditions a contraindication to its use. This risk is exacerbated when bupropion is combined with other drugs or substances that lower the seizure threshold, such as cocaine, or in clinical situations that would increase the risk of a seizure such as abrupt alcohol or benzodiazepine withdrawal. As norepinephrine has been shown to have anticonvulsant properties, bupropion's inhibitory effects on NET are thought to contribute to its pro-convulsant activity. Bupropion has been shown to increase blood pressure and pose a risk for exacerbation of unmanaged or pre-existing hypertension, however, clinical trials of bupropion in smokers with CVD have not identified an increased incidence of CV events including stroke or heart attack. In clinical trials, the mean increase in systolic blood pressure associated with the use of bupropion was found to be 1.3 mmHg. •Pharmacodynamics (Drug B): Nedocromil is a anti-inflammatory agent and can be administered directly to the bronchial mucosa. It has significant inhibitory effect on allergen-induced early and late asthmatic reactions and on bronchial hyperresponsiveness. •Mechanism of action (Drug A): Bupropion is a norepinephrine/dopamine-reuptake inhibitor (NDRI) that exerts its pharmacological effects by weakly inhibiting the enzymes involved in the uptake of the neurotransmitters norepinephrine and dopamine from the synaptic cleft, therefore prolonging their duration of action within the neuronal synapse and the downstream effects of these neurotransmitters. More specifically, bupropion binds to the norepinephrine transporter (NET) and the dopamine transporter (DAT). Bupropion was originally classified as an "atypical" antidepressant because it does not exert the same effects as the classical antidepressants such as Monoamine Oxidase Inhibitors (MAOIs), Tricyclic Antidepressants (TCAs), or Selective Serotonin Reuptake Inhibitors (SSRIs). While it has comparable effectiveness to typical first-line options for the treatment of depression such as SSRIs, bupropion is a unique option for the treatment of MDD as it lacks any clinically relevant serotonergic effects, typical of other mood medications, or any effects on histamine or adrenaline receptors. Lack of activity at these receptors results in a more tolerable side effect profile; bupropion is less likely to cause sexual side effects, sedation, or weight gain as compared to SSRIs or TCAs, for example. When used as an aid to smoking cessation, bupropion is thought to confer its anti-craving and anti-withdrawal effects by inhibiting dopamine reuptake, which is thought to be involved in the reward pathways associated with nicotine, and through the antagonism of the nicotinic acetylcholinergic receptor (AChR), thereby blunting the effects of nicotine. Furthermore, the stimulatory effects produced by bupropion in the central nervous system are similar to nicotine's effects, making low doses of bupropion a suitable option as a nicotine substitute. When used in combination with naltrexone in the marketed product ContraveⓇ for chronic weight management, the two components are thought to have effects on areas of the brain involved in the regulation of food intake. This includes the hypothalamus, which is involved in appetite regulation, and the mesolimbic dopamine circuit, which is involved in reward pathways. Studies have shown that the combined activity of bupropion and naltrexone increase the firing rate of hypothalamic pro-opiomelanocortin (POMC) neurons and blockade of opioid receptor-mediated POMC auto-inhibition, which are associated with a reduction in food intake and increased energy expenditure. This combination was also found to reduce food intake when injected directly into the ventral tegmental area of the mesolimbic circuit in mice, which is an area associated with the regulation of reward pathways. •Mechanism of action (Drug B): Nedocromil has been shown to inhibit the in vitro activation of, and mediator release from, a variety of inflammatory cell types associated with asthma, including eosinophils, neutrophils, macrophages, mast cells, monocytes, and platelets. Nedocromil inhibits activation and release of inflammatory mediators such as histamine, prostaglandin D2 and leukotrienes c4 from different types of cells in the lumen and mucosa of the bronchial tree. These mediators are derived from arachidonic acid metabolism through the lipoxygenase and cyclo-oxygenase pathways. The mechanism of action of nedocromil may be due partly to inhibition of axon reflexes and release of sensory neuropeptides, such as substance P, neurokinin A, and calcitonin-geneñrelated peptides. The result is inhibition of bradykinin-induced bronchoconstriction. Nedocromil does not posess any bronchodilator, antihistamine, or corticosteroid activity. •Absorption (Drug A): Bupropion is currently available in 3 distinct, but bioequivalent formulations: immediate release (IR), sustained-release (SR), and extended-release (XL). Immediate Release Formulation In humans, following oral administration of bupropion hydrochloride tablets, peak plasma bupropion concentrations are usually achieved within 2 hours. IR formulations provide a short duration of action and are therefore generally dosed three times per day. Sustained Release Formulation In humans, following oral administration of bupropion hydrochloride sustained-release tablets (SR), peak plasma concentration (Cmax) of bupropion is usually achieved within 3 hours. SR formulations provide a 12-hour extended release of medication and are therefore generally dosed twice per day. Extended Release Formulation Following single oral administration of bupropion hydrochloride extended-release tablets (XL) to healthy volunteers, the median time to peak plasma concentrations for bupropion was approximately 5 hours. The presence of food did not affect the peak concentration or area under the curve of bupropion. XL formulations provide a 24-hour extended release of medication and are therefore generally dosed once per day/ In a trial comparing chronic dosing with bupropion hydrochloride extended-release tablets (SR) 150 mg twice daily to bupropion immediate-release formulation 100 mg 3 times daily, the steady state Cmax for bupropion after bupropion hydrochloride sustained-release tablets (SR) administration was approximately 85% of those achieved after bupropion immediate-release formulation administration. Exposure (AUC) to bupropion was equivalent for both formulations. Bioequivalence was also demonstrated for all three major active metabolites (i.e., hydroxybupropion, threohydrobupropion and erythrohydrobupropion) for both Cmax and AUC. Thus, at steady state, bupropion hydrochloride sustained-release tablets (SR) given twice daily, and the immediate-release formulation of bupropion given 3 times daily, are essentially bioequivalent for both bupropion and the 3 quantitatively important metabolites. Furthermore, in a study comparing 14-day dosing with bupropion hydrochloride extended-release tablets (XL), 300 mg once-daily to the immediate-release formulation of bupropion at 100 mg 3 times daily, equivalence was demonstrated for peak plasma concentration and area under the curve for bupropion and the three metabolites (hydroxybupropion, threohydrobupropion, and erythrohydrobupropion). Additionally, in a study comparing 14-day dosing with bupropion hydrochloride extended-release tablets (XL) 300 mg once daily to the sustained-release formulation of bupropion at 150 mg 2 times daily, equivalence was demonstrated for peak plasma concentration and area under the curve for bupropion and the three metabolites. Bupropion hydrochloride extended-release tablets (SR) can be taken with or without food. Bupropion Cmax and AUC were increased by 11% to 35% and 16% to 19%, respectively, when bupropion hydrochloride extended-release tablets (SR) was administered with food to healthy volunteers in three trials. The food effect is not considered clinically significant. Following a single-dose administration of bupropion hydrochloride extended-release tablets (SR) in humans, Cmax of bupropion's metabolite hydroxybupropion occurs approximately 6 hours post-dose and is approximately 10 times the peak level of the parent drug at steady state. The elimination half-life of hydroxybupropion is approximately 20 (±5) hours and its AUC at steady state is about 17 times that of bupropion. The times to peak concentrations for the erythrohydrobupropion and threohydrobupropion metabolites are similar to that of the hydroxybupropion metabolite. However, their elimination half-lives are longer, 33(±10) and 37 (±13) hours, respectively, and steady-state AUCs are 1.5 and 7 times that of bupropion, respectively. •Absorption (Drug B): Low •Volume of distribution (Drug A): No volume of distribution available •Volume of distribution (Drug B): No volume of distribution available •Protein binding (Drug A): In vitro tests show that bupropion is 84% bound to human plasma proteins at concentrations up to 200 mcg per mL. The extent of protein binding of the hydroxybupropion metabolite is similar to that for bupropion, whereas the extent of protein binding of the threohydrobupropion metabolite is about half that seen with bupropion. •Protein binding (Drug B): approximately 89% protein bound in human plasma over a concentration range of 0.5 to 50 µg/mL •Metabolism (Drug A): Bupropion is extensively metabolized in humans. Three metabolites are active: hydroxybupropion, which is formed via hydroxylation of the tert-butyl group of bupropion, and the amino-alcohol isomers, threohydrobupropion and erythrohydrobupropion, which are formed via reduction of the carbonyl group. In vitro findings suggest that CYP2B6 is the principal isoenzyme involved in the formation of hydroxybupropion, while cytochrome P450 enzymes are not involved in the formation of threohydrobupropion. Hydroxybupropion has been shown to have the same affinity as bupropion for the norepinephrine transporter (NET) but approximately 50% of its antidepressant activity despite reaching concentrations of ~10-fold higher than that of the parent drug. Oxidation of the bupropion side chain results in the formation of a glycine conjugate of meta-chlorobenzoic acid, which is then excreted as the major urinary metabolite. The potency and toxicity of the metabolites relative to bupropion have not been fully characterized. However, it has been demonstrated in an antidepressant screening test in mice that hydroxybupropion is one-half as potent as bupropion, while threohydrobupropion and erythrohydrobupropion are 5-fold less potent than bupropion. This may be of clinical importance because the plasma concentrations of the metabolites are as high as or higher than those of bupropion. Bupropion and its metabolites exhibit linear kinetics following chronic administration of 300 to 450 mg per day. •Metabolism (Drug B): Nedocromil is not metabolized after IV administration and is excreted unchanged. •Route of elimination (Drug A): Bupropion is extensively metabolized in humans. Oxidation of the bupropion side chain results in the formation of a glycine conjugate of metachlorobenzoic acid, which is then excreted as the major urinary metabolite. Following oral administration of 200 mg of 14C-bupropion in humans, 87% and 10% of the radioactive dose were recovered in the urine and feces, respectively. However, the fraction of the oral dose of bupropion excreted unchanged was only 0.5%, a finding consistent with the extensive metabolism of bupropion. •Route of elimination (Drug B): It is not metabolized and is eliminated primarily unchanged in urine (70%) and feces (30%). •Half-life (Drug A): 24 hours •Half-life (Drug B): ~3.3 hours •Clearance (Drug A): No clearance available •Clearance (Drug B): No clearance available •Toxicity (Drug A): Symptoms of overdose include seizures, hallucinations, loss of consciousness, tachycardia, and cardiac arrest. •Toxicity (Drug B): Side effects include headache, nasal congestion, ocular burning, irritation and stinging, unpleasant taste, cough, difficulty breathing, noisy breathing, shortness of breath, tightness in chest, wheezing, conjunctivitis, blurred vision, change in color vision, difficulty seeing at night, increased sensitivity of eyes to sunlight. •Brand Names (Drug A): Aplenzin, Auvelity, Budeprion, Contrave, Forfivo, Wellbutrin, Zyban •Brand Names (Drug B): Alocril •Synonyms (Drug A): No synonyms listed •Synonyms (Drug B): Nedocromil Nédocromil Nedocromilo Nedocromilum •Summary (Drug A): Bupropion is a norepinephrine and dopamine reuptake inhibitor used in the treatment of major depressive disorder (MDD), seasonal affective disorder (SAD), and as an aid to smoking cessation. •Summary (Drug B): Nedocromil is a pyrano quinoline used to treat allergic conjunctivitis. Output: The renal excretion of drugs is the overall result of a combination of kidney processes that include glomerular filtration, passive diffusion, tubular secretion, and tubular reabsorption. Since two of these mechanisms - tubular secretion and reabsorption - are saturable processes , they are consequently susceptible to competition between multiple substrates excreted by the kidneys. If two or more medications that are mainly renally excreted are co-administered, they may compete for renal elimination; there is a large likelihood that one agent may "out-compete" or saturate the renal excretion mechanisms before the other concomitantly administered agent(s) are excreted. As a result, the elimination of these other concurrently administered agents may be inhibited or otherwise delayed, which could lead to increases in their serum concentrations and the risk, incidence, and/or severity of adverse effects associated with the exposure to such drugs. The severity of the interaction is minor.

Does Bupropion and Nefazodone interact?

•Drug A: Bupropion •Drug B: Nefazodone •Severity: MAJOR •Description: The metabolism of Nefazodone can be decreased when combined with Bupropion. •Extended Description: The subject drug is a strong CYP2D6 inhibitor and the affected drug is metabolized by CYP2D6. Concomitant administration may decrease the metabolism of the affected drug, which could increase serum concentrations as well as the risk and severity of adverse effects. •Indication (Drug A): Bupropion is indicated for the treatment of major depressive disorder (MDD), seasonal affective disorder (SAD), and as an aid to smoking cessation. When used in combination with naltrexone as the marketed product ContraveⓇ, bupropion is indicated as an adjunct to a reduced-calorie diet and increased physical activity for chronic weight management in adults with an initial body mass index (BMI) of: 30 kg/m^2 or greater (obese) or 27 kg/m^2 or greater (overweight) in the presence of at least one weight-related comorbid condition (e.g., hypertension, type 2 diabetes mellitus, or dyslipidemia). Bupropion is also used off-label as a first-line treatment in patients with ADHD and comorbid bipolar disorder when used as an adjunct to mood stabilizers. •Indication (Drug B): For the treatment of depression. •Pharmacodynamics (Drug A): Bupropion is chemically unrelated to tricyclic, tetracyclic, selective serotonin re-uptake inhibitors, or other known antidepressant agents. Compared to classical tricyclic antidepressants, Bupropion is a relatively weak inhibitor of the neuronal uptake of norepinephrine and dopamine. In addition, Bupropion does not inhibit monoamine oxidase. Bupropion has been found to be essentially inactive at the serotonin transporter (SERT)(IC50 >10 000 nM), however both bupropion and its primary metabolite hydroxybupropion have been found to block the function of cation-selective serotonin type 3A receptors (5-HT3ARs). Bupropion produces dose-related central nervous system (CNS) stimulant effects in animals, as evidenced by increased locomotor activity, increased rates of responding in various schedule-controlled operant behaviour tasks, and, at high doses, induction of mild stereotyped behaviour. Due to these stimulant effects and selective activity at dopamine and norepinephrine receptors, bupropion has been identified as having an abuse potential. Bupropion has a similar structure to the controlled substance Cathinone, and has been identified as having mild amphetamine-like activity, particularly when inhaled or injected. Bupropion is also known to lower the seizure threshold, making any pre-existing seizure conditions a contraindication to its use. This risk is exacerbated when bupropion is combined with other drugs or substances that lower the seizure threshold, such as cocaine, or in clinical situations that would increase the risk of a seizure such as abrupt alcohol or benzodiazepine withdrawal. As norepinephrine has been shown to have anticonvulsant properties, bupropion's inhibitory effects on NET are thought to contribute to its pro-convulsant activity. Bupropion has been shown to increase blood pressure and pose a risk for exacerbation of unmanaged or pre-existing hypertension, however, clinical trials of bupropion in smokers with CVD have not identified an increased incidence of CV events including stroke or heart attack. In clinical trials, the mean increase in systolic blood pressure associated with the use of bupropion was found to be 1.3 mmHg. •Pharmacodynamics (Drug B): Nefazodone, an antidepressant synthetically derived phenylpiperazine, is used to treat major depression. Although it is structurally similar to trazodone, nefazodone has a mechanism of action different from other antidepressants and, hence, lacks the risk for major cardiovascular toxicity seen with tricyclics and insomnia and inhibition of REM sleep seen with the selective serotonin reuptake inhibitors. •Mechanism of action (Drug A): Bupropion is a norepinephrine/dopamine-reuptake inhibitor (NDRI) that exerts its pharmacological effects by weakly inhibiting the enzymes involved in the uptake of the neurotransmitters norepinephrine and dopamine from the synaptic cleft, therefore prolonging their duration of action within the neuronal synapse and the downstream effects of these neurotransmitters. More specifically, bupropion binds to the norepinephrine transporter (NET) and the dopamine transporter (DAT). Bupropion was originally classified as an "atypical" antidepressant because it does not exert the same effects as the classical antidepressants such as Monoamine Oxidase Inhibitors (MAOIs), Tricyclic Antidepressants (TCAs), or Selective Serotonin Reuptake Inhibitors (SSRIs). While it has comparable effectiveness to typical first-line options for the treatment of depression such as SSRIs, bupropion is a unique option for the treatment of MDD as it lacks any clinically relevant serotonergic effects, typical of other mood medications, or any effects on histamine or adrenaline receptors. Lack of activity at these receptors results in a more tolerable side effect profile; bupropion is less likely to cause sexual side effects, sedation, or weight gain as compared to SSRIs or TCAs, for example. When used as an aid to smoking cessation, bupropion is thought to confer its anti-craving and anti-withdrawal effects by inhibiting dopamine reuptake, which is thought to be involved in the reward pathways associated with nicotine, and through the antagonism of the nicotinic acetylcholinergic receptor (AChR), thereby blunting the effects of nicotine. Furthermore, the stimulatory effects produced by bupropion in the central nervous system are similar to nicotine's effects, making low doses of bupropion a suitable option as a nicotine substitute. When used in combination with naltrexone in the marketed product ContraveⓇ for chronic weight management, the two components are thought to have effects on areas of the brain involved in the regulation of food intake. This includes the hypothalamus, which is involved in appetite regulation, and the mesolimbic dopamine circuit, which is involved in reward pathways. Studies have shown that the combined activity of bupropion and naltrexone increase the firing rate of hypothalamic pro-opiomelanocortin (POMC) neurons and blockade of opioid receptor-mediated POMC auto-inhibition, which are associated with a reduction in food intake and increased energy expenditure. This combination was also found to reduce food intake when injected directly into the ventral tegmental area of the mesolimbic circuit in mice, which is an area associated with the regulation of reward pathways. •Mechanism of action (Drug B): Within the serotonergic system, nefazodone acts as an antagonist at type 2 serotonin (5-HT 2 ) post-synaptic receptors and, like fluoxetine-type antidepressants, inhibits pre-synaptic serotonin (5-HT) reuptake. These mechanisms increase the amount of serotonin available to interact with 5-HT receptors. Within the noradrenergic system, nefazodone inhibits norepinephrine uptake minimally. Nefazodone also antagonizes alpha(1)-adrenergic receptors, producing sedation, muscle relaxation, and a variety of cardiovascular effects. Nefazodone's affinity for benzodiazepine, cholinergic, dopaminergic, histaminic, and beta or alpha(2)-adrenergic receptors is not significant. •Absorption (Drug A): Bupropion is currently available in 3 distinct, but bioequivalent formulations: immediate release (IR), sustained-release (SR), and extended-release (XL). Immediate Release Formulation In humans, following oral administration of bupropion hydrochloride tablets, peak plasma bupropion concentrations are usually achieved within 2 hours. IR formulations provide a short duration of action and are therefore generally dosed three times per day. Sustained Release Formulation In humans, following oral administration of bupropion hydrochloride sustained-release tablets (SR), peak plasma concentration (Cmax) of bupropion is usually achieved within 3 hours. SR formulations provide a 12-hour extended release of medication and are therefore generally dosed twice per day. Extended Release Formulation Following single oral administration of bupropion hydrochloride extended-release tablets (XL) to healthy volunteers, the median time to peak plasma concentrations for bupropion was approximately 5 hours. The presence of food did not affect the peak concentration or area under the curve of bupropion. XL formulations provide a 24-hour extended release of medication and are therefore generally dosed once per day/ In a trial comparing chronic dosing with bupropion hydrochloride extended-release tablets (SR) 150 mg twice daily to bupropion immediate-release formulation 100 mg 3 times daily, the steady state Cmax for bupropion after bupropion hydrochloride sustained-release tablets (SR) administration was approximately 85% of those achieved after bupropion immediate-release formulation administration. Exposure (AUC) to bupropion was equivalent for both formulations. Bioequivalence was also demonstrated for all three major active metabolites (i.e., hydroxybupropion, threohydrobupropion and erythrohydrobupropion) for both Cmax and AUC. Thus, at steady state, bupropion hydrochloride sustained-release tablets (SR) given twice daily, and the immediate-release formulation of bupropion given 3 times daily, are essentially bioequivalent for both bupropion and the 3 quantitatively important metabolites. Furthermore, in a study comparing 14-day dosing with bupropion hydrochloride extended-release tablets (XL), 300 mg once-daily to the immediate-release formulation of bupropion at 100 mg 3 times daily, equivalence was demonstrated for peak plasma concentration and area under the curve for bupropion and the three metabolites (hydroxybupropion, threohydrobupropion, and erythrohydrobupropion). Additionally, in a study comparing 14-day dosing with bupropion hydrochloride extended-release tablets (XL) 300 mg once daily to the sustained-release formulation of bupropion at 150 mg 2 times daily, equivalence was demonstrated for peak plasma concentration and area under the curve for bupropion and the three metabolites. Bupropion hydrochloride extended-release tablets (SR) can be taken with or without food. Bupropion Cmax and AUC were increased by 11% to 35% and 16% to 19%, respectively, when bupropion hydrochloride extended-release tablets (SR) was administered with food to healthy volunteers in three trials. The food effect is not considered clinically significant. Following a single-dose administration of bupropion hydrochloride extended-release tablets (SR) in humans, Cmax of bupropion's metabolite hydroxybupropion occurs approximately 6 hours post-dose and is approximately 10 times the peak level of the parent drug at steady state. The elimination half-life of hydroxybupropion is approximately 20 (±5) hours and its AUC at steady state is about 17 times that of bupropion. The times to peak concentrations for the erythrohydrobupropion and threohydrobupropion metabolites are similar to that of the hydroxybupropion metabolite. However, their elimination half-lives are longer, 33(±10) and 37 (±13) hours, respectively, and steady-state AUCs are 1.5 and 7 times that of bupropion, respectively. •Absorption (Drug B): Nefazodone is rapidly and completely absorbed. Its absolute bioavailability is low (about 20%). •Volume of distribution (Drug A): No volume of distribution available •Volume of distribution (Drug B): 0.22 to 0.87 L/kg •Protein binding (Drug A): In vitro tests show that bupropion is 84% bound to human plasma proteins at concentrations up to 200 mcg per mL. The extent of protein binding of the hydroxybupropion metabolite is similar to that for bupropion, whereas the extent of protein binding of the threohydrobupropion metabolite is about half that seen with bupropion. •Protein binding (Drug B): Greater than 99% (in vitro, human plasma proteins). •Metabolism (Drug A): Bupropion is extensively metabolized in humans. Three metabolites are active: hydroxybupropion, which is formed via hydroxylation of the tert-butyl group of bupropion, and the amino-alcohol isomers, threohydrobupropion and erythrohydrobupropion, which are formed via reduction of the carbonyl group. In vitro findings suggest that CYP2B6 is the principal isoenzyme involved in the formation of hydroxybupropion, while cytochrome P450 enzymes are not involved in the formation of threohydrobupropion. Hydroxybupropion has been shown to have the same affinity as bupropion for the norepinephrine transporter (NET) but approximately 50% of its antidepressant activity despite reaching concentrations of ~10-fold higher than that of the parent drug. Oxidation of the bupropion side chain results in the formation of a glycine conjugate of meta-chlorobenzoic acid, which is then excreted as the major urinary metabolite. The potency and toxicity of the metabolites relative to bupropion have not been fully characterized. However, it has been demonstrated in an antidepressant screening test in mice that hydroxybupropion is one-half as potent as bupropion, while threohydrobupropion and erythrohydrobupropion are 5-fold less potent than bupropion. This may be of clinical importance because the plasma concentrations of the metabolites are as high as or higher than those of bupropion. Bupropion and its metabolites exhibit linear kinetics following chronic administration of 300 to 450 mg per day. •Metabolism (Drug B): Hepatic. •Route of elimination (Drug A): Bupropion is extensively metabolized in humans. Oxidation of the bupropion side chain results in the formation of a glycine conjugate of metachlorobenzoic acid, which is then excreted as the major urinary metabolite. Following oral administration of 200 mg of 14C-bupropion in humans, 87% and 10% of the radioactive dose were recovered in the urine and feces, respectively. However, the fraction of the oral dose of bupropion excreted unchanged was only 0.5%, a finding consistent with the extensive metabolism of bupropion. •Route of elimination (Drug B): Nefazodone is extensively metabolized after oral administration by n-dealkylation and aliphatic and aromatic hydroxylation, and less than 1% of administered nefazodone is excreted unchanged in urine. •Half-life (Drug A): 24 hours •Half-life (Drug B): 2-4 hours •Clearance (Drug A): No clearance available •Clearance (Drug B): No clearance available •Toxicity (Drug A): Symptoms of overdose include seizures, hallucinations, loss of consciousness, tachycardia, and cardiac arrest. •Toxicity (Drug B): Cases of life-threatening hepatic failure have been reported in patients treated with nefazodone. •Brand Names (Drug A): Aplenzin, Auvelity, Budeprion, Contrave, Forfivo, Wellbutrin, Zyban •Brand Names (Drug B): No brand names available •Synonyms (Drug A): No synonyms listed •Synonyms (Drug B): Nefazodona Nefazodone Nefazodonum •Summary (Drug A): Bupropion is a norepinephrine and dopamine reuptake inhibitor used in the treatment of major depressive disorder (MDD), seasonal affective disorder (SAD), and as an aid to smoking cessation. •Summary (Drug B): Nefazodone is an antidepressant used in the treatment of depression.

The subject drug is a strong CYP2D6 inhibitor and the affected drug is metabolized by CYP2D6. Concomitant administration may decrease the metabolism of the affected drug, which could increase serum concentrations as well as the risk and severity of adverse effects. The severity of the interaction is major.

Question: Does Bupropion and Nefazodone interact? Information: •Drug A: Bupropion •Drug B: Nefazodone •Severity: MAJOR •Description: The metabolism of Nefazodone can be decreased when combined with Bupropion. •Extended Description: The subject drug is a strong CYP2D6 inhibitor and the affected drug is metabolized by CYP2D6. Concomitant administration may decrease the metabolism of the affected drug, which could increase serum concentrations as well as the risk and severity of adverse effects. •Indication (Drug A): Bupropion is indicated for the treatment of major depressive disorder (MDD), seasonal affective disorder (SAD), and as an aid to smoking cessation. When used in combination with naltrexone as the marketed product ContraveⓇ, bupropion is indicated as an adjunct to a reduced-calorie diet and increased physical activity for chronic weight management in adults with an initial body mass index (BMI) of: 30 kg/m^2 or greater (obese) or 27 kg/m^2 or greater (overweight) in the presence of at least one weight-related comorbid condition (e.g., hypertension, type 2 diabetes mellitus, or dyslipidemia). Bupropion is also used off-label as a first-line treatment in patients with ADHD and comorbid bipolar disorder when used as an adjunct to mood stabilizers. •Indication (Drug B): For the treatment of depression. •Pharmacodynamics (Drug A): Bupropion is chemically unrelated to tricyclic, tetracyclic, selective serotonin re-uptake inhibitors, or other known antidepressant agents. Compared to classical tricyclic antidepressants, Bupropion is a relatively weak inhibitor of the neuronal uptake of norepinephrine and dopamine. In addition, Bupropion does not inhibit monoamine oxidase. Bupropion has been found to be essentially inactive at the serotonin transporter (SERT)(IC50 >10 000 nM), however both bupropion and its primary metabolite hydroxybupropion have been found to block the function of cation-selective serotonin type 3A receptors (5-HT3ARs). Bupropion produces dose-related central nervous system (CNS) stimulant effects in animals, as evidenced by increased locomotor activity, increased rates of responding in various schedule-controlled operant behaviour tasks, and, at high doses, induction of mild stereotyped behaviour. Due to these stimulant effects and selective activity at dopamine and norepinephrine receptors, bupropion has been identified as having an abuse potential. Bupropion has a similar structure to the controlled substance Cathinone, and has been identified as having mild amphetamine-like activity, particularly when inhaled or injected. Bupropion is also known to lower the seizure threshold, making any pre-existing seizure conditions a contraindication to its use. This risk is exacerbated when bupropion is combined with other drugs or substances that lower the seizure threshold, such as cocaine, or in clinical situations that would increase the risk of a seizure such as abrupt alcohol or benzodiazepine withdrawal. As norepinephrine has been shown to have anticonvulsant properties, bupropion's inhibitory effects on NET are thought to contribute to its pro-convulsant activity. Bupropion has been shown to increase blood pressure and pose a risk for exacerbation of unmanaged or pre-existing hypertension, however, clinical trials of bupropion in smokers with CVD have not identified an increased incidence of CV events including stroke or heart attack. In clinical trials, the mean increase in systolic blood pressure associated with the use of bupropion was found to be 1.3 mmHg. •Pharmacodynamics (Drug B): Nefazodone, an antidepressant synthetically derived phenylpiperazine, is used to treat major depression. Although it is structurally similar to trazodone, nefazodone has a mechanism of action different from other antidepressants and, hence, lacks the risk for major cardiovascular toxicity seen with tricyclics and insomnia and inhibition of REM sleep seen with the selective serotonin reuptake inhibitors. •Mechanism of action (Drug A): Bupropion is a norepinephrine/dopamine-reuptake inhibitor (NDRI) that exerts its pharmacological effects by weakly inhibiting the enzymes involved in the uptake of the neurotransmitters norepinephrine and dopamine from the synaptic cleft, therefore prolonging their duration of action within the neuronal synapse and the downstream effects of these neurotransmitters. More specifically, bupropion binds to the norepinephrine transporter (NET) and the dopamine transporter (DAT). Bupropion was originally classified as an "atypical" antidepressant because it does not exert the same effects as the classical antidepressants such as Monoamine Oxidase Inhibitors (MAOIs), Tricyclic Antidepressants (TCAs), or Selective Serotonin Reuptake Inhibitors (SSRIs). While it has comparable effectiveness to typical first-line options for the treatment of depression such as SSRIs, bupropion is a unique option for the treatment of MDD as it lacks any clinically relevant serotonergic effects, typical of other mood medications, or any effects on histamine or adrenaline receptors. Lack of activity at these receptors results in a more tolerable side effect profile; bupropion is less likely to cause sexual side effects, sedation, or weight gain as compared to SSRIs or TCAs, for example. When used as an aid to smoking cessation, bupropion is thought to confer its anti-craving and anti-withdrawal effects by inhibiting dopamine reuptake, which is thought to be involved in the reward pathways associated with nicotine, and through the antagonism of the nicotinic acetylcholinergic receptor (AChR), thereby blunting the effects of nicotine. Furthermore, the stimulatory effects produced by bupropion in the central nervous system are similar to nicotine's effects, making low doses of bupropion a suitable option as a nicotine substitute. When used in combination with naltrexone in the marketed product ContraveⓇ for chronic weight management, the two components are thought to have effects on areas of the brain involved in the regulation of food intake. This includes the hypothalamus, which is involved in appetite regulation, and the mesolimbic dopamine circuit, which is involved in reward pathways. Studies have shown that the combined activity of bupropion and naltrexone increase the firing rate of hypothalamic pro-opiomelanocortin (POMC) neurons and blockade of opioid receptor-mediated POMC auto-inhibition, which are associated with a reduction in food intake and increased energy expenditure. This combination was also found to reduce food intake when injected directly into the ventral tegmental area of the mesolimbic circuit in mice, which is an area associated with the regulation of reward pathways. •Mechanism of action (Drug B): Within the serotonergic system, nefazodone acts as an antagonist at type 2 serotonin (5-HT 2 ) post-synaptic receptors and, like fluoxetine-type antidepressants, inhibits pre-synaptic serotonin (5-HT) reuptake. These mechanisms increase the amount of serotonin available to interact with 5-HT receptors. Within the noradrenergic system, nefazodone inhibits norepinephrine uptake minimally. Nefazodone also antagonizes alpha(1)-adrenergic receptors, producing sedation, muscle relaxation, and a variety of cardiovascular effects. Nefazodone's affinity for benzodiazepine, cholinergic, dopaminergic, histaminic, and beta or alpha(2)-adrenergic receptors is not significant. •Absorption (Drug A): Bupropion is currently available in 3 distinct, but bioequivalent formulations: immediate release (IR), sustained-release (SR), and extended-release (XL). Immediate Release Formulation In humans, following oral administration of bupropion hydrochloride tablets, peak plasma bupropion concentrations are usually achieved within 2 hours. IR formulations provide a short duration of action and are therefore generally dosed three times per day. Sustained Release Formulation In humans, following oral administration of bupropion hydrochloride sustained-release tablets (SR), peak plasma concentration (Cmax) of bupropion is usually achieved within 3 hours. SR formulations provide a 12-hour extended release of medication and are therefore generally dosed twice per day. Extended Release Formulation Following single oral administration of bupropion hydrochloride extended-release tablets (XL) to healthy volunteers, the median time to peak plasma concentrations for bupropion was approximately 5 hours. The presence of food did not affect the peak concentration or area under the curve of bupropion. XL formulations provide a 24-hour extended release of medication and are therefore generally dosed once per day/ In a trial comparing chronic dosing with bupropion hydrochloride extended-release tablets (SR) 150 mg twice daily to bupropion immediate-release formulation 100 mg 3 times daily, the steady state Cmax for bupropion after bupropion hydrochloride sustained-release tablets (SR) administration was approximately 85% of those achieved after bupropion immediate-release formulation administration. Exposure (AUC) to bupropion was equivalent for both formulations. Bioequivalence was also demonstrated for all three major active metabolites (i.e., hydroxybupropion, threohydrobupropion and erythrohydrobupropion) for both Cmax and AUC. Thus, at steady state, bupropion hydrochloride sustained-release tablets (SR) given twice daily, and the immediate-release formulation of bupropion given 3 times daily, are essentially bioequivalent for both bupropion and the 3 quantitatively important metabolites. Furthermore, in a study comparing 14-day dosing with bupropion hydrochloride extended-release tablets (XL), 300 mg once-daily to the immediate-release formulation of bupropion at 100 mg 3 times daily, equivalence was demonstrated for peak plasma concentration and area under the curve for bupropion and the three metabolites (hydroxybupropion, threohydrobupropion, and erythrohydrobupropion). Additionally, in a study comparing 14-day dosing with bupropion hydrochloride extended-release tablets (XL) 300 mg once daily to the sustained-release formulation of bupropion at 150 mg 2 times daily, equivalence was demonstrated for peak plasma concentration and area under the curve for bupropion and the three metabolites. Bupropion hydrochloride extended-release tablets (SR) can be taken with or without food. Bupropion Cmax and AUC were increased by 11% to 35% and 16% to 19%, respectively, when bupropion hydrochloride extended-release tablets (SR) was administered with food to healthy volunteers in three trials. The food effect is not considered clinically significant. Following a single-dose administration of bupropion hydrochloride extended-release tablets (SR) in humans, Cmax of bupropion's metabolite hydroxybupropion occurs approximately 6 hours post-dose and is approximately 10 times the peak level of the parent drug at steady state. The elimination half-life of hydroxybupropion is approximately 20 (±5) hours and its AUC at steady state is about 17 times that of bupropion. The times to peak concentrations for the erythrohydrobupropion and threohydrobupropion metabolites are similar to that of the hydroxybupropion metabolite. However, their elimination half-lives are longer, 33(±10) and 37 (±13) hours, respectively, and steady-state AUCs are 1.5 and 7 times that of bupropion, respectively. •Absorption (Drug B): Nefazodone is rapidly and completely absorbed. Its absolute bioavailability is low (about 20%). •Volume of distribution (Drug A): No volume of distribution available •Volume of distribution (Drug B): 0.22 to 0.87 L/kg •Protein binding (Drug A): In vitro tests show that bupropion is 84% bound to human plasma proteins at concentrations up to 200 mcg per mL. The extent of protein binding of the hydroxybupropion metabolite is similar to that for bupropion, whereas the extent of protein binding of the threohydrobupropion metabolite is about half that seen with bupropion. •Protein binding (Drug B): Greater than 99% (in vitro, human plasma proteins). •Metabolism (Drug A): Bupropion is extensively metabolized in humans. Three metabolites are active: hydroxybupropion, which is formed via hydroxylation of the tert-butyl group of bupropion, and the amino-alcohol isomers, threohydrobupropion and erythrohydrobupropion, which are formed via reduction of the carbonyl group. In vitro findings suggest that CYP2B6 is the principal isoenzyme involved in the formation of hydroxybupropion, while cytochrome P450 enzymes are not involved in the formation of threohydrobupropion. Hydroxybupropion has been shown to have the same affinity as bupropion for the norepinephrine transporter (NET) but approximately 50% of its antidepressant activity despite reaching concentrations of ~10-fold higher than that of the parent drug. Oxidation of the bupropion side chain results in the formation of a glycine conjugate of meta-chlorobenzoic acid, which is then excreted as the major urinary metabolite. The potency and toxicity of the metabolites relative to bupropion have not been fully characterized. However, it has been demonstrated in an antidepressant screening test in mice that hydroxybupropion is one-half as potent as bupropion, while threohydrobupropion and erythrohydrobupropion are 5-fold less potent than bupropion. This may be of clinical importance because the plasma concentrations of the metabolites are as high as or higher than those of bupropion. Bupropion and its metabolites exhibit linear kinetics following chronic administration of 300 to 450 mg per day. •Metabolism (Drug B): Hepatic. •Route of elimination (Drug A): Bupropion is extensively metabolized in humans. Oxidation of the bupropion side chain results in the formation of a glycine conjugate of metachlorobenzoic acid, which is then excreted as the major urinary metabolite. Following oral administration of 200 mg of 14C-bupropion in humans, 87% and 10% of the radioactive dose were recovered in the urine and feces, respectively. However, the fraction of the oral dose of bupropion excreted unchanged was only 0.5%, a finding consistent with the extensive metabolism of bupropion. •Route of elimination (Drug B): Nefazodone is extensively metabolized after oral administration by n-dealkylation and aliphatic and aromatic hydroxylation, and less than 1% of administered nefazodone is excreted unchanged in urine. •Half-life (Drug A): 24 hours •Half-life (Drug B): 2-4 hours •Clearance (Drug A): No clearance available •Clearance (Drug B): No clearance available •Toxicity (Drug A): Symptoms of overdose include seizures, hallucinations, loss of consciousness, tachycardia, and cardiac arrest. •Toxicity (Drug B): Cases of life-threatening hepatic failure have been reported in patients treated with nefazodone. •Brand Names (Drug A): Aplenzin, Auvelity, Budeprion, Contrave, Forfivo, Wellbutrin, Zyban •Brand Names (Drug B): No brand names available •Synonyms (Drug A): No synonyms listed •Synonyms (Drug B): Nefazodona Nefazodone Nefazodonum •Summary (Drug A): Bupropion is a norepinephrine and dopamine reuptake inhibitor used in the treatment of major depressive disorder (MDD), seasonal affective disorder (SAD), and as an aid to smoking cessation. •Summary (Drug B): Nefazodone is an antidepressant used in the treatment of depression. Output: The subject drug is a strong CYP2D6 inhibitor and the affected drug is metabolized by CYP2D6. Concomitant administration may decrease the metabolism of the affected drug, which could increase serum concentrations as well as the risk and severity of adverse effects. The severity of the interaction is major.

Does Bupropion and Nelfinavir interact?

•Drug A: Bupropion •Drug B: Nelfinavir •Severity: MINOR •Description: The serum concentration of Bupropion can be increased when it is combined with Nelfinavir. •Extended Description: Bupropion is extensively metabolized to hydroxybupropion by CYP2B6. •Indication (Drug A): Bupropion is indicated for the treatment of major depressive disorder (MDD), seasonal affective disorder (SAD), and as an aid to smoking cessation. When used in combination with naltrexone as the marketed product ContraveⓇ, bupropion is indicated as an adjunct to a reduced-calorie diet and increased physical activity for chronic weight management in adults with an initial body mass index (BMI) of: 30 kg/m^2 or greater (obese) or 27 kg/m^2 or greater (overweight) in the presence of at least one weight-related comorbid condition (e.g., hypertension, type 2 diabetes mellitus, or dyslipidemia). Bupropion is also used off-label as a first-line treatment in patients with ADHD and comorbid bipolar disorder when used as an adjunct to mood stabilizers. •Indication (Drug B): Used in combination with other antiviral drugs in the treatment of HIV in both adults and children. •Pharmacodynamics (Drug A): Bupropion is chemically unrelated to tricyclic, tetracyclic, selective serotonin re-uptake inhibitors, or other known antidepressant agents. Compared to classical tricyclic antidepressants, Bupropion is a relatively weak inhibitor of the neuronal uptake of norepinephrine and dopamine. In addition, Bupropion does not inhibit monoamine oxidase. Bupropion has been found to be essentially inactive at the serotonin transporter (SERT)(IC50 >10 000 nM), however both bupropion and its primary metabolite hydroxybupropion have been found to block the function of cation-selective serotonin type 3A receptors (5-HT3ARs). Bupropion produces dose-related central nervous system (CNS) stimulant effects in animals, as evidenced by increased locomotor activity, increased rates of responding in various schedule-controlled operant behaviour tasks, and, at high doses, induction of mild stereotyped behaviour. Due to these stimulant effects and selective activity at dopamine and norepinephrine receptors, bupropion has been identified as having an abuse potential. Bupropion has a similar structure to the controlled substance Cathinone, and has been identified as having mild amphetamine-like activity, particularly when inhaled or injected. Bupropion is also known to lower the seizure threshold, making any pre-existing seizure conditions a contraindication to its use. This risk is exacerbated when bupropion is combined with other drugs or substances that lower the seizure threshold, such as cocaine, or in clinical situations that would increase the risk of a seizure such as abrupt alcohol or benzodiazepine withdrawal. As norepinephrine has been shown to have anticonvulsant properties, bupropion's inhibitory effects on NET are thought to contribute to its pro-convulsant activity. Bupropion has been shown to increase blood pressure and pose a risk for exacerbation of unmanaged or pre-existing hypertension, however, clinical trials of bupropion in smokers with CVD have not identified an increased incidence of CV events including stroke or heart attack. In clinical trials, the mean increase in systolic blood pressure associated with the use of bupropion was found to be 1.3 mmHg. •Pharmacodynamics (Drug B): Nelfinavir is a protease inhibitor with activity against Human Immunodeficiency Virus Type 1 (HIV-1). Protease inhibitors block the part of HIV called protease. HIV-1 protease is an enzyme required for the proteolytic cleavage of the viral polyprotein precursors into the individual functional proteins found in infectious HIV-1. Nelfinavir binds to the protease active site and inhibits the activity of the enzyme. This inhibition prevents cleavage of the viral polyproteins resulting in the formation of immature non-infectious viral particles. Protease inhibitors are almost always used in combination with at least two other anti-HIV drugs. •Mechanism of action (Drug A): Bupropion is a norepinephrine/dopamine-reuptake inhibitor (NDRI) that exerts its pharmacological effects by weakly inhibiting the enzymes involved in the uptake of the neurotransmitters norepinephrine and dopamine from the synaptic cleft, therefore prolonging their duration of action within the neuronal synapse and the downstream effects of these neurotransmitters. More specifically, bupropion binds to the norepinephrine transporter (NET) and the dopamine transporter (DAT). Bupropion was originally classified as an "atypical" antidepressant because it does not exert the same effects as the classical antidepressants such as Monoamine Oxidase Inhibitors (MAOIs), Tricyclic Antidepressants (TCAs), or Selective Serotonin Reuptake Inhibitors (SSRIs). While it has comparable effectiveness to typical first-line options for the treatment of depression such as SSRIs, bupropion is a unique option for the treatment of MDD as it lacks any clinically relevant serotonergic effects, typical of other mood medications, or any effects on histamine or adrenaline receptors. Lack of activity at these receptors results in a more tolerable side effect profile; bupropion is less likely to cause sexual side effects, sedation, or weight gain as compared to SSRIs or TCAs, for example. When used as an aid to smoking cessation, bupropion is thought to confer its anti-craving and anti-withdrawal effects by inhibiting dopamine reuptake, which is thought to be involved in the reward pathways associated with nicotine, and through the antagonism of the nicotinic acetylcholinergic receptor (AChR), thereby blunting the effects of nicotine. Furthermore, the stimulatory effects produced by bupropion in the central nervous system are similar to nicotine's effects, making low doses of bupropion a suitable option as a nicotine substitute. When used in combination with naltrexone in the marketed product ContraveⓇ for chronic weight management, the two components are thought to have effects on areas of the brain involved in the regulation of food intake. This includes the hypothalamus, which is involved in appetite regulation, and the mesolimbic dopamine circuit, which is involved in reward pathways. Studies have shown that the combined activity of bupropion and naltrexone increase the firing rate of hypothalamic pro-opiomelanocortin (POMC) neurons and blockade of opioid receptor-mediated POMC auto-inhibition, which are associated with a reduction in food intake and increased energy expenditure. This combination was also found to reduce food intake when injected directly into the ventral tegmental area of the mesolimbic circuit in mice, which is an area associated with the regulation of reward pathways. •Mechanism of action (Drug B): HIV viral protease is an important enzyme for HIV maturation and pathogenicity since HIV produces its structural and key proteins in the form of a polyprotein that needs to be cleaved by a protease. HIV protease is synthesized as part of the Gag-pol polyprotein, where Gag encodes for the capsid and matrix protein to form the outer protein shell, and Pol encodes for the reverse transcriptase and integrase protein to synthesize and incorporate its genome into host cells. The Gag-pol polyprotein undergoes proteolytic cleavage by HIV protease to produce 66 molecular species which will assume conformational changes to become fully active. Inhibition of protease, therefore, prevents HIV virion from fully maturing and becoming infective. Nelfinavir is a competitive inhibitor of the HIV protease by reversibly binding to the active site of the enzyme, preventing it from interacting with its substrate to produce mature and infectious viral particles. •Absorption (Drug A): Bupropion is currently available in 3 distinct, but bioequivalent formulations: immediate release (IR), sustained-release (SR), and extended-release (XL). Immediate Release Formulation In humans, following oral administration of bupropion hydrochloride tablets, peak plasma bupropion concentrations are usually achieved within 2 hours. IR formulations provide a short duration of action and are therefore generally dosed three times per day. Sustained Release Formulation In humans, following oral administration of bupropion hydrochloride sustained-release tablets (SR), peak plasma concentration (Cmax) of bupropion is usually achieved within 3 hours. SR formulations provide a 12-hour extended release of medication and are therefore generally dosed twice per day. Extended Release Formulation Following single oral administration of bupropion hydrochloride extended-release tablets (XL) to healthy volunteers, the median time to peak plasma concentrations for bupropion was approximately 5 hours. The presence of food did not affect the peak concentration or area under the curve of bupropion. XL formulations provide a 24-hour extended release of medication and are therefore generally dosed once per day/ In a trial comparing chronic dosing with bupropion hydrochloride extended-release tablets (SR) 150 mg twice daily to bupropion immediate-release formulation 100 mg 3 times daily, the steady state Cmax for bupropion after bupropion hydrochloride sustained-release tablets (SR) administration was approximately 85% of those achieved after bupropion immediate-release formulation administration. Exposure (AUC) to bupropion was equivalent for both formulations. Bioequivalence was also demonstrated for all three major active metabolites (i.e., hydroxybupropion, threohydrobupropion and erythrohydrobupropion) for both Cmax and AUC. Thus, at steady state, bupropion hydrochloride sustained-release tablets (SR) given twice daily, and the immediate-release formulation of bupropion given 3 times daily, are essentially bioequivalent for both bupropion and the 3 quantitatively important metabolites. Furthermore, in a study comparing 14-day dosing with bupropion hydrochloride extended-release tablets (XL), 300 mg once-daily to the immediate-release formulation of bupropion at 100 mg 3 times daily, equivalence was demonstrated for peak plasma concentration and area under the curve for bupropion and the three metabolites (hydroxybupropion, threohydrobupropion, and erythrohydrobupropion). Additionally, in a study comparing 14-day dosing with bupropion hydrochloride extended-release tablets (XL) 300 mg once daily to the sustained-release formulation of bupropion at 150 mg 2 times daily, equivalence was demonstrated for peak plasma concentration and area under the curve for bupropion and the three metabolites. Bupropion hydrochloride extended-release tablets (SR) can be taken with or without food. Bupropion Cmax and AUC were increased by 11% to 35% and 16% to 19%, respectively, when bupropion hydrochloride extended-release tablets (SR) was administered with food to healthy volunteers in three trials. The food effect is not considered clinically significant. Following a single-dose administration of bupropion hydrochloride extended-release tablets (SR) in humans, Cmax of bupropion's metabolite hydroxybupropion occurs approximately 6 hours post-dose and is approximately 10 times the peak level of the parent drug at steady state. The elimination half-life of hydroxybupropion is approximately 20 (±5) hours and its AUC at steady state is about 17 times that of bupropion. The times to peak concentrations for the erythrohydrobupropion and threohydrobupropion metabolites are similar to that of the hydroxybupropion metabolite. However, their elimination half-lives are longer, 33(±10) and 37 (±13) hours, respectively, and steady-state AUCs are 1.5 and 7 times that of bupropion, respectively. •Absorption (Drug B): Well absorbed following oral administration. •Volume of distribution (Drug A): No volume of distribution available •Volume of distribution (Drug B): The apparent volume of distribution following oral administration of nelfinavir was 2-7 L/kg. •Protein binding (Drug A): In vitro tests show that bupropion is 84% bound to human plasma proteins at concentrations up to 200 mcg per mL. The extent of protein binding of the hydroxybupropion metabolite is similar to that for bupropion, whereas the extent of protein binding of the threohydrobupropion metabolite is about half that seen with bupropion. •Protein binding (Drug B): Nelfinavir in serum is extensively protein-bound (>98%). •Metabolism (Drug A): Bupropion is extensively metabolized in humans. Three metabolites are active: hydroxybupropion, which is formed via hydroxylation of the tert-butyl group of bupropion, and the amino-alcohol isomers, threohydrobupropion and erythrohydrobupropion, which are formed via reduction of the carbonyl group. In vitro findings suggest that CYP2B6 is the principal isoenzyme involved in the formation of hydroxybupropion, while cytochrome P450 enzymes are not involved in the formation of threohydrobupropion. Hydroxybupropion has been shown to have the same affinity as bupropion for the norepinephrine transporter (NET) but approximately 50% of its antidepressant activity despite reaching concentrations of ~10-fold higher than that of the parent drug. Oxidation of the bupropion side chain results in the formation of a glycine conjugate of meta-chlorobenzoic acid, which is then excreted as the major urinary metabolite. The potency and toxicity of the metabolites relative to bupropion have not been fully characterized. However, it has been demonstrated in an antidepressant screening test in mice that hydroxybupropion is one-half as potent as bupropion, while threohydrobupropion and erythrohydrobupropion are 5-fold less potent than bupropion. This may be of clinical importance because the plasma concentrations of the metabolites are as high as or higher than those of bupropion. Bupropion and its metabolites exhibit linear kinetics following chronic administration of 300 to 450 mg per day. •Metabolism (Drug B): Unchanged nelfinavir comprised 82-86% of the total plasma radioactivity after a single oral 750 mg dose of 14C-nelfinavir. In vitro, multiple cytochrome P-450 enzymes including CYP3A and CYP2C19 are responsible for the metabolism of nelfinavir. One major and several minor oxidative metabolites were found in plasma. The major oxidative metabolite has in vitro antiviral activity comparable to the parent drug. •Route of elimination (Drug A): Bupropion is extensively metabolized in humans. Oxidation of the bupropion side chain results in the formation of a glycine conjugate of metachlorobenzoic acid, which is then excreted as the major urinary metabolite. Following oral administration of 200 mg of 14C-bupropion in humans, 87% and 10% of the radioactive dose were recovered in the urine and feces, respectively. However, the fraction of the oral dose of bupropion excreted unchanged was only 0.5%, a finding consistent with the extensive metabolism of bupropion. •Route of elimination (Drug B): The majority (87%) of an oral 750 mg dose containing 14C-nelfinavir was recovered in the feces; fecal radioactivity consisted of numerous oxidative metabolites (78%) and unchanged nelfinavir (22%). Only 1–2% of the dose was recovered in urine, of which unchanged nelfinavir was the major component. •Half-life (Drug A): 24 hours •Half-life (Drug B): The terminal half-life in plasma was typically 3.5 to 5 hours. •Clearance (Drug A): No clearance available •Clearance (Drug B): Oral clearance estimates after single doses (24-33 L/h) and multiple doses (26-61 L/h) indicate that nelfinavir is a drug with medium to high hepatic bioavailability. •Toxicity (Drug A): Symptoms of overdose include seizures, hallucinations, loss of consciousness, tachycardia, and cardiac arrest. •Toxicity (Drug B): Carcinogenicity studies in mice and rats were conducted with nelfinavir at oral doses up to 1000 mg/kg/day. No evidence of a tumorigenic effect was noted in mice at systemic exposures (Cmax) up to 9-fold those measured in humans at the recommended therapeutic dose (750 mg TID or 1250 mg BID). In rats, thyroid follicular cell adenomas and carcinomas were increased in males at 300 mg/kg/day and higher and in females at 1000 mg/kg/day. Systemic exposures (Cmax) at 300 and 1000 mg/kg/day were 1- to 3-fold, respectively, those measured in humans at the recommended therapeutic dose. Repeated administration of nelfinavir to rats produced effects consistent with hepatic microsomal enzyme induction and increased thyroid hormone deposition; these effects predispose rats, but not humans, to thyroid follicular cell neoplasms. Nelfinavir showed no evidence of mutagenic or clastogenic activity in a battery of in vitro and in vivo genetic toxicology assays. These studies included bacterial mutation assays in S. typhimurium and E. coli, a mouse lymphoma tyrosine kinase assay, a chromosomal aberration assay in human lymphocytes, and an in vivo mouse bone marrow micronucleus assay. Nelfinavir produced no effects on either male or female mating and fertility or embryo survival in rats at systemic exposures comparable to the human therapeutic exposure. Human experience of acute overdose with nelfinavir is limited. There is no specific antidote for overdose with VIRACEPT. If indicated, elimination of unabsorbed drug should be achieved by emesis or gastric lavage. Administration of activated charcoal may also be used to aid the removal of unabsorbed drug. Since nelfinavir is highly protein-bound, dialysis is unlikely to significantly remove the drug from blood. •Brand Names (Drug A): Aplenzin, Auvelity, Budeprion, Contrave, Forfivo, Wellbutrin, Zyban •Brand Names (Drug B): Viracept •Synonyms (Drug A): No synonyms listed •Synonyms (Drug B): No synonyms listed •Summary (Drug A): Bupropion is a norepinephrine and dopamine reuptake inhibitor used in the treatment of major depressive disorder (MDD), seasonal affective disorder (SAD), and as an aid to smoking cessation. •Summary (Drug B): Nelfinavir is a viral protease inhibitor used in the treatment of HIV infection.

Bupropion is extensively metabolized to hydroxybupropion by CYP2B6. The severity of the interaction is minor.

Question: Does Bupropion and Nelfinavir interact? Information: •Drug A: Bupropion •Drug B: Nelfinavir •Severity: MINOR •Description: The serum concentration of Bupropion can be increased when it is combined with Nelfinavir. •Extended Description: Bupropion is extensively metabolized to hydroxybupropion by CYP2B6. •Indication (Drug A): Bupropion is indicated for the treatment of major depressive disorder (MDD), seasonal affective disorder (SAD), and as an aid to smoking cessation. When used in combination with naltrexone as the marketed product ContraveⓇ, bupropion is indicated as an adjunct to a reduced-calorie diet and increased physical activity for chronic weight management in adults with an initial body mass index (BMI) of: 30 kg/m^2 or greater (obese) or 27 kg/m^2 or greater (overweight) in the presence of at least one weight-related comorbid condition (e.g., hypertension, type 2 diabetes mellitus, or dyslipidemia). Bupropion is also used off-label as a first-line treatment in patients with ADHD and comorbid bipolar disorder when used as an adjunct to mood stabilizers. •Indication (Drug B): Used in combination with other antiviral drugs in the treatment of HIV in both adults and children. •Pharmacodynamics (Drug A): Bupropion is chemically unrelated to tricyclic, tetracyclic, selective serotonin re-uptake inhibitors, or other known antidepressant agents. Compared to classical tricyclic antidepressants, Bupropion is a relatively weak inhibitor of the neuronal uptake of norepinephrine and dopamine. In addition, Bupropion does not inhibit monoamine oxidase. Bupropion has been found to be essentially inactive at the serotonin transporter (SERT)(IC50 >10 000 nM), however both bupropion and its primary metabolite hydroxybupropion have been found to block the function of cation-selective serotonin type 3A receptors (5-HT3ARs). Bupropion produces dose-related central nervous system (CNS) stimulant effects in animals, as evidenced by increased locomotor activity, increased rates of responding in various schedule-controlled operant behaviour tasks, and, at high doses, induction of mild stereotyped behaviour. Due to these stimulant effects and selective activity at dopamine and norepinephrine receptors, bupropion has been identified as having an abuse potential. Bupropion has a similar structure to the controlled substance Cathinone, and has been identified as having mild amphetamine-like activity, particularly when inhaled or injected. Bupropion is also known to lower the seizure threshold, making any pre-existing seizure conditions a contraindication to its use. This risk is exacerbated when bupropion is combined with other drugs or substances that lower the seizure threshold, such as cocaine, or in clinical situations that would increase the risk of a seizure such as abrupt alcohol or benzodiazepine withdrawal. As norepinephrine has been shown to have anticonvulsant properties, bupropion's inhibitory effects on NET are thought to contribute to its pro-convulsant activity. Bupropion has been shown to increase blood pressure and pose a risk for exacerbation of unmanaged or pre-existing hypertension, however, clinical trials of bupropion in smokers with CVD have not identified an increased incidence of CV events including stroke or heart attack. In clinical trials, the mean increase in systolic blood pressure associated with the use of bupropion was found to be 1.3 mmHg. •Pharmacodynamics (Drug B): Nelfinavir is a protease inhibitor with activity against Human Immunodeficiency Virus Type 1 (HIV-1). Protease inhibitors block the part of HIV called protease. HIV-1 protease is an enzyme required for the proteolytic cleavage of the viral polyprotein precursors into the individual functional proteins found in infectious HIV-1. Nelfinavir binds to the protease active site and inhibits the activity of the enzyme. This inhibition prevents cleavage of the viral polyproteins resulting in the formation of immature non-infectious viral particles. Protease inhibitors are almost always used in combination with at least two other anti-HIV drugs. •Mechanism of action (Drug A): Bupropion is a norepinephrine/dopamine-reuptake inhibitor (NDRI) that exerts its pharmacological effects by weakly inhibiting the enzymes involved in the uptake of the neurotransmitters norepinephrine and dopamine from the synaptic cleft, therefore prolonging their duration of action within the neuronal synapse and the downstream effects of these neurotransmitters. More specifically, bupropion binds to the norepinephrine transporter (NET) and the dopamine transporter (DAT). Bupropion was originally classified as an "atypical" antidepressant because it does not exert the same effects as the classical antidepressants such as Monoamine Oxidase Inhibitors (MAOIs), Tricyclic Antidepressants (TCAs), or Selective Serotonin Reuptake Inhibitors (SSRIs). While it has comparable effectiveness to typical first-line options for the treatment of depression such as SSRIs, bupropion is a unique option for the treatment of MDD as it lacks any clinically relevant serotonergic effects, typical of other mood medications, or any effects on histamine or adrenaline receptors. Lack of activity at these receptors results in a more tolerable side effect profile; bupropion is less likely to cause sexual side effects, sedation, or weight gain as compared to SSRIs or TCAs, for example. When used as an aid to smoking cessation, bupropion is thought to confer its anti-craving and anti-withdrawal effects by inhibiting dopamine reuptake, which is thought to be involved in the reward pathways associated with nicotine, and through the antagonism of the nicotinic acetylcholinergic receptor (AChR), thereby blunting the effects of nicotine. Furthermore, the stimulatory effects produced by bupropion in the central nervous system are similar to nicotine's effects, making low doses of bupropion a suitable option as a nicotine substitute. When used in combination with naltrexone in the marketed product ContraveⓇ for chronic weight management, the two components are thought to have effects on areas of the brain involved in the regulation of food intake. This includes the hypothalamus, which is involved in appetite regulation, and the mesolimbic dopamine circuit, which is involved in reward pathways. Studies have shown that the combined activity of bupropion and naltrexone increase the firing rate of hypothalamic pro-opiomelanocortin (POMC) neurons and blockade of opioid receptor-mediated POMC auto-inhibition, which are associated with a reduction in food intake and increased energy expenditure. This combination was also found to reduce food intake when injected directly into the ventral tegmental area of the mesolimbic circuit in mice, which is an area associated with the regulation of reward pathways. •Mechanism of action (Drug B): HIV viral protease is an important enzyme for HIV maturation and pathogenicity since HIV produces its structural and key proteins in the form of a polyprotein that needs to be cleaved by a protease. HIV protease is synthesized as part of the Gag-pol polyprotein, where Gag encodes for the capsid and matrix protein to form the outer protein shell, and Pol encodes for the reverse transcriptase and integrase protein to synthesize and incorporate its genome into host cells. The Gag-pol polyprotein undergoes proteolytic cleavage by HIV protease to produce 66 molecular species which will assume conformational changes to become fully active. Inhibition of protease, therefore, prevents HIV virion from fully maturing and becoming infective. Nelfinavir is a competitive inhibitor of the HIV protease by reversibly binding to the active site of the enzyme, preventing it from interacting with its substrate to produce mature and infectious viral particles. •Absorption (Drug A): Bupropion is currently available in 3 distinct, but bioequivalent formulations: immediate release (IR), sustained-release (SR), and extended-release (XL). Immediate Release Formulation In humans, following oral administration of bupropion hydrochloride tablets, peak plasma bupropion concentrations are usually achieved within 2 hours. IR formulations provide a short duration of action and are therefore generally dosed three times per day. Sustained Release Formulation In humans, following oral administration of bupropion hydrochloride sustained-release tablets (SR), peak plasma concentration (Cmax) of bupropion is usually achieved within 3 hours. SR formulations provide a 12-hour extended release of medication and are therefore generally dosed twice per day. Extended Release Formulation Following single oral administration of bupropion hydrochloride extended-release tablets (XL) to healthy volunteers, the median time to peak plasma concentrations for bupropion was approximately 5 hours. The presence of food did not affect the peak concentration or area under the curve of bupropion. XL formulations provide a 24-hour extended release of medication and are therefore generally dosed once per day/ In a trial comparing chronic dosing with bupropion hydrochloride extended-release tablets (SR) 150 mg twice daily to bupropion immediate-release formulation 100 mg 3 times daily, the steady state Cmax for bupropion after bupropion hydrochloride sustained-release tablets (SR) administration was approximately 85% of those achieved after bupropion immediate-release formulation administration. Exposure (AUC) to bupropion was equivalent for both formulations. Bioequivalence was also demonstrated for all three major active metabolites (i.e., hydroxybupropion, threohydrobupropion and erythrohydrobupropion) for both Cmax and AUC. Thus, at steady state, bupropion hydrochloride sustained-release tablets (SR) given twice daily, and the immediate-release formulation of bupropion given 3 times daily, are essentially bioequivalent for both bupropion and the 3 quantitatively important metabolites. Furthermore, in a study comparing 14-day dosing with bupropion hydrochloride extended-release tablets (XL), 300 mg once-daily to the immediate-release formulation of bupropion at 100 mg 3 times daily, equivalence was demonstrated for peak plasma concentration and area under the curve for bupropion and the three metabolites (hydroxybupropion, threohydrobupropion, and erythrohydrobupropion). Additionally, in a study comparing 14-day dosing with bupropion hydrochloride extended-release tablets (XL) 300 mg once daily to the sustained-release formulation of bupropion at 150 mg 2 times daily, equivalence was demonstrated for peak plasma concentration and area under the curve for bupropion and the three metabolites. Bupropion hydrochloride extended-release tablets (SR) can be taken with or without food. Bupropion Cmax and AUC were increased by 11% to 35% and 16% to 19%, respectively, when bupropion hydrochloride extended-release tablets (SR) was administered with food to healthy volunteers in three trials. The food effect is not considered clinically significant. Following a single-dose administration of bupropion hydrochloride extended-release tablets (SR) in humans, Cmax of bupropion's metabolite hydroxybupropion occurs approximately 6 hours post-dose and is approximately 10 times the peak level of the parent drug at steady state. The elimination half-life of hydroxybupropion is approximately 20 (±5) hours and its AUC at steady state is about 17 times that of bupropion. The times to peak concentrations for the erythrohydrobupropion and threohydrobupropion metabolites are similar to that of the hydroxybupropion metabolite. However, their elimination half-lives are longer, 33(±10) and 37 (±13) hours, respectively, and steady-state AUCs are 1.5 and 7 times that of bupropion, respectively. •Absorption (Drug B): Well absorbed following oral administration. •Volume of distribution (Drug A): No volume of distribution available •Volume of distribution (Drug B): The apparent volume of distribution following oral administration of nelfinavir was 2-7 L/kg. •Protein binding (Drug A): In vitro tests show that bupropion is 84% bound to human plasma proteins at concentrations up to 200 mcg per mL. The extent of protein binding of the hydroxybupropion metabolite is similar to that for bupropion, whereas the extent of protein binding of the threohydrobupropion metabolite is about half that seen with bupropion. •Protein binding (Drug B): Nelfinavir in serum is extensively protein-bound (>98%). •Metabolism (Drug A): Bupropion is extensively metabolized in humans. Three metabolites are active: hydroxybupropion, which is formed via hydroxylation of the tert-butyl group of bupropion, and the amino-alcohol isomers, threohydrobupropion and erythrohydrobupropion, which are formed via reduction of the carbonyl group. In vitro findings suggest that CYP2B6 is the principal isoenzyme involved in the formation of hydroxybupropion, while cytochrome P450 enzymes are not involved in the formation of threohydrobupropion. Hydroxybupropion has been shown to have the same affinity as bupropion for the norepinephrine transporter (NET) but approximately 50% of its antidepressant activity despite reaching concentrations of ~10-fold higher than that of the parent drug. Oxidation of the bupropion side chain results in the formation of a glycine conjugate of meta-chlorobenzoic acid, which is then excreted as the major urinary metabolite. The potency and toxicity of the metabolites relative to bupropion have not been fully characterized. However, it has been demonstrated in an antidepressant screening test in mice that hydroxybupropion is one-half as potent as bupropion, while threohydrobupropion and erythrohydrobupropion are 5-fold less potent than bupropion. This may be of clinical importance because the plasma concentrations of the metabolites are as high as or higher than those of bupropion. Bupropion and its metabolites exhibit linear kinetics following chronic administration of 300 to 450 mg per day. •Metabolism (Drug B): Unchanged nelfinavir comprised 82-86% of the total plasma radioactivity after a single oral 750 mg dose of 14C-nelfinavir. In vitro, multiple cytochrome P-450 enzymes including CYP3A and CYP2C19 are responsible for the metabolism of nelfinavir. One major and several minor oxidative metabolites were found in plasma. The major oxidative metabolite has in vitro antiviral activity comparable to the parent drug. •Route of elimination (Drug A): Bupropion is extensively metabolized in humans. Oxidation of the bupropion side chain results in the formation of a glycine conjugate of metachlorobenzoic acid, which is then excreted as the major urinary metabolite. Following oral administration of 200 mg of 14C-bupropion in humans, 87% and 10% of the radioactive dose were recovered in the urine and feces, respectively. However, the fraction of the oral dose of bupropion excreted unchanged was only 0.5%, a finding consistent with the extensive metabolism of bupropion. •Route of elimination (Drug B): The majority (87%) of an oral 750 mg dose containing 14C-nelfinavir was recovered in the feces; fecal radioactivity consisted of numerous oxidative metabolites (78%) and unchanged nelfinavir (22%). Only 1–2% of the dose was recovered in urine, of which unchanged nelfinavir was the major component. •Half-life (Drug A): 24 hours •Half-life (Drug B): The terminal half-life in plasma was typically 3.5 to 5 hours. •Clearance (Drug A): No clearance available •Clearance (Drug B): Oral clearance estimates after single doses (24-33 L/h) and multiple doses (26-61 L/h) indicate that nelfinavir is a drug with medium to high hepatic bioavailability. •Toxicity (Drug A): Symptoms of overdose include seizures, hallucinations, loss of consciousness, tachycardia, and cardiac arrest. •Toxicity (Drug B): Carcinogenicity studies in mice and rats were conducted with nelfinavir at oral doses up to 1000 mg/kg/day. No evidence of a tumorigenic effect was noted in mice at systemic exposures (Cmax) up to 9-fold those measured in humans at the recommended therapeutic dose (750 mg TID or 1250 mg BID). In rats, thyroid follicular cell adenomas and carcinomas were increased in males at 300 mg/kg/day and higher and in females at 1000 mg/kg/day. Systemic exposures (Cmax) at 300 and 1000 mg/kg/day were 1- to 3-fold, respectively, those measured in humans at the recommended therapeutic dose. Repeated administration of nelfinavir to rats produced effects consistent with hepatic microsomal enzyme induction and increased thyroid hormone deposition; these effects predispose rats, but not humans, to thyroid follicular cell neoplasms. Nelfinavir showed no evidence of mutagenic or clastogenic activity in a battery of in vitro and in vivo genetic toxicology assays. These studies included bacterial mutation assays in S. typhimurium and E. coli, a mouse lymphoma tyrosine kinase assay, a chromosomal aberration assay in human lymphocytes, and an in vivo mouse bone marrow micronucleus assay. Nelfinavir produced no effects on either male or female mating and fertility or embryo survival in rats at systemic exposures comparable to the human therapeutic exposure. Human experience of acute overdose with nelfinavir is limited. There is no specific antidote for overdose with VIRACEPT. If indicated, elimination of unabsorbed drug should be achieved by emesis or gastric lavage. Administration of activated charcoal may also be used to aid the removal of unabsorbed drug. Since nelfinavir is highly protein-bound, dialysis is unlikely to significantly remove the drug from blood. •Brand Names (Drug A): Aplenzin, Auvelity, Budeprion, Contrave, Forfivo, Wellbutrin, Zyban •Brand Names (Drug B): Viracept •Synonyms (Drug A): No synonyms listed •Synonyms (Drug B): No synonyms listed •Summary (Drug A): Bupropion is a norepinephrine and dopamine reuptake inhibitor used in the treatment of major depressive disorder (MDD), seasonal affective disorder (SAD), and as an aid to smoking cessation. •Summary (Drug B): Nelfinavir is a viral protease inhibitor used in the treatment of HIV infection. Output: Bupropion is extensively metabolized to hydroxybupropion by CYP2B6. The severity of the interaction is minor.

Does Bupropion and Neomycin interact?

•Drug A: Bupropion •Drug B: Neomycin •Severity: MODERATE •Description: Bupropion may decrease the excretion rate of Neomycin which could result in a higher serum level. •Extended Description: The renal excretion of drugs is the overall result of a combination of kidney processes that include glomerular filtration, passive diffusion, tubular secretion, and tubular reabsorption. Since two of these mechanisms - tubular secretion and reabsorption - are saturable processes , they are consequently susceptible to competition between multiple substrates excreted by the kidneys. If two or more medications that are mainly renally excreted are co-administered, they may compete for renal elimination; there is a large likelihood that one agent may "out-compete" or saturate the renal excretion mechanisms before the other concomitantly administered agent(s) are excreted. As a result, the elimination of these other concurrently administered agents may be inhibited or otherwise delayed, which could lead to increases in their serum concentrations and the risk, incidence, and/or severity of adverse effects associated with the exposure to such drugs. The affected drug is a narrow therapeutic index drug that undergoes renal excretion as its main elimination pathway: a change in serum concentration may significantly elevate the risk of developing drug-related adverse effects. •Indication (Drug A): Bupropion is indicated for the treatment of major depressive disorder (MDD), seasonal affective disorder (SAD), and as an aid to smoking cessation. When used in combination with naltrexone as the marketed product ContraveⓇ, bupropion is indicated as an adjunct to a reduced-calorie diet and increased physical activity for chronic weight management in adults with an initial body mass index (BMI) of: 30 kg/m^2 or greater (obese) or 27 kg/m^2 or greater (overweight) in the presence of at least one weight-related comorbid condition (e.g., hypertension, type 2 diabetes mellitus, or dyslipidemia). Bupropion is also used off-label as a first-line treatment in patients with ADHD and comorbid bipolar disorder when used as an adjunct to mood stabilizers. •Indication (Drug B): Oral neomycin sulfate is indicated as an adjunctive therapy in hepatic coma (portal-system encephalopathy) by reducing ammonia-forming bacteria in the intestinal tract. It is strongly recommended that oral neomycin is only used in infections that are proven or strongly suspected to be caused by susceptible bacteria to reduce the risk of the development of drug-resistant bacteria. Neomycin, in combination with polymyxin B sulfates and hydrocortisone in otic suspensions, is used in the treatment of superficial bacterial infections of the external auditory canal caused by organisms susceptible to the antibiotics. This otic formulation is also used in the treatment of infections of mastoidectomy and fenestration cavities caused by organisms susceptible to the antibiotics. The ophthalmic solution containing neomycin in combination with polymyxin B sulfates and dexamethasone is used to treat steroid-responsive inflammatory ocular conditions for which a corticosteroid is indicated and where bacterial infection or a risk of bacterial infection exists. •Pharmacodynamics (Drug A): Bupropion is chemically unrelated to tricyclic, tetracyclic, selective serotonin re-uptake inhibitors, or other known antidepressant agents. Compared to classical tricyclic antidepressants, Bupropion is a relatively weak inhibitor of the neuronal uptake of norepinephrine and dopamine. In addition, Bupropion does not inhibit monoamine oxidase. Bupropion has been found to be essentially inactive at the serotonin transporter (SERT)(IC50 >10 000 nM), however both bupropion and its primary metabolite hydroxybupropion have been found to block the function of cation-selective serotonin type 3A receptors (5-HT3ARs). Bupropion produces dose-related central nervous system (CNS) stimulant effects in animals, as evidenced by increased locomotor activity, increased rates of responding in various schedule-controlled operant behaviour tasks, and, at high doses, induction of mild stereotyped behaviour. Due to these stimulant effects and selective activity at dopamine and norepinephrine receptors, bupropion has been identified as having an abuse potential. Bupropion has a similar structure to the controlled substance Cathinone, and has been identified as having mild amphetamine-like activity, particularly when inhaled or injected. Bupropion is also known to lower the seizure threshold, making any pre-existing seizure conditions a contraindication to its use. This risk is exacerbated when bupropion is combined with other drugs or substances that lower the seizure threshold, such as cocaine, or in clinical situations that would increase the risk of a seizure such as abrupt alcohol or benzodiazepine withdrawal. As norepinephrine has been shown to have anticonvulsant properties, bupropion's inhibitory effects on NET are thought to contribute to its pro-convulsant activity. Bupropion has been shown to increase blood pressure and pose a risk for exacerbation of unmanaged or pre-existing hypertension, however, clinical trials of bupropion in smokers with CVD have not identified an increased incidence of CV events including stroke or heart attack. In clinical trials, the mean increase in systolic blood pressure associated with the use of bupropion was found to be 1.3 mmHg. •Pharmacodynamics (Drug B): Neomycin mediates its bactericidal action by inhibiting bacterial protein synthesis, thereby suppressing the growth and survival of susceptible bacteria. Following oral administration, the duration of bactericidal activity of neomycin ranged from 48 to 72 hours. By decreasing colonic bacteria that produce ammonia, neomycin was shown to be effective as an adjunctive therapy in hepatic coma to improve neurologic symptoms. Neomycin is active against both gram positive and gram negative organisms, including the major E. coli species resident in the colon as well as the enteropathogenic forms of E. coli. It is also active against Klebsiella - Enterobacter group. Resistant strains of E. coli, Klebsiella and Proteus spp. may emerge from neomycin therapy. Neomycin has no antifungal activity and has some activity against some protozoa. •Mechanism of action (Drug A): Bupropion is a norepinephrine/dopamine-reuptake inhibitor (NDRI) that exerts its pharmacological effects by weakly inhibiting the enzymes involved in the uptake of the neurotransmitters norepinephrine and dopamine from the synaptic cleft, therefore prolonging their duration of action within the neuronal synapse and the downstream effects of these neurotransmitters. More specifically, bupropion binds to the norepinephrine transporter (NET) and the dopamine transporter (DAT). Bupropion was originally classified as an "atypical" antidepressant because it does not exert the same effects as the classical antidepressants such as Monoamine Oxidase Inhibitors (MAOIs), Tricyclic Antidepressants (TCAs), or Selective Serotonin Reuptake Inhibitors (SSRIs). While it has comparable effectiveness to typical first-line options for the treatment of depression such as SSRIs, bupropion is a unique option for the treatment of MDD as it lacks any clinically relevant serotonergic effects, typical of other mood medications, or any effects on histamine or adrenaline receptors. Lack of activity at these receptors results in a more tolerable side effect profile; bupropion is less likely to cause sexual side effects, sedation, or weight gain as compared to SSRIs or TCAs, for example. When used as an aid to smoking cessation, bupropion is thought to confer its anti-craving and anti-withdrawal effects by inhibiting dopamine reuptake, which is thought to be involved in the reward pathways associated with nicotine, and through the antagonism of the nicotinic acetylcholinergic receptor (AChR), thereby blunting the effects of nicotine. Furthermore, the stimulatory effects produced by bupropion in the central nervous system are similar to nicotine's effects, making low doses of bupropion a suitable option as a nicotine substitute. When used in combination with naltrexone in the marketed product ContraveⓇ for chronic weight management, the two components are thought to have effects on areas of the brain involved in the regulation of food intake. This includes the hypothalamus, which is involved in appetite regulation, and the mesolimbic dopamine circuit, which is involved in reward pathways. Studies have shown that the combined activity of bupropion and naltrexone increase the firing rate of hypothalamic pro-opiomelanocortin (POMC) neurons and blockade of opioid receptor-mediated POMC auto-inhibition, which are associated with a reduction in food intake and increased energy expenditure. This combination was also found to reduce food intake when injected directly into the ventral tegmental area of the mesolimbic circuit in mice, which is an area associated with the regulation of reward pathways. •Mechanism of action (Drug B): Like other aminoglycoside antibiotic drugs, neomycin inhibits bacterial ribosomes by binding to the 30S ribosomal subunit of susceptible bacteria and disrupting the translational machinery of bacterial protein synthesis. Bacterial translation is normally initiated by the mRNA binding to the 30S ribosomal subunit and subsequent binding with 50S subunit for elongation. •Absorption (Drug A): Bupropion is currently available in 3 distinct, but bioequivalent formulations: immediate release (IR), sustained-release (SR), and extended-release (XL). Immediate Release Formulation In humans, following oral administration of bupropion hydrochloride tablets, peak plasma bupropion concentrations are usually achieved within 2 hours. IR formulations provide a short duration of action and are therefore generally dosed three times per day. Sustained Release Formulation In humans, following oral administration of bupropion hydrochloride sustained-release tablets (SR), peak plasma concentration (Cmax) of bupropion is usually achieved within 3 hours. SR formulations provide a 12-hour extended release of medication and are therefore generally dosed twice per day. Extended Release Formulation Following single oral administration of bupropion hydrochloride extended-release tablets (XL) to healthy volunteers, the median time to peak plasma concentrations for bupropion was approximately 5 hours. The presence of food did not affect the peak concentration or area under the curve of bupropion. XL formulations provide a 24-hour extended release of medication and are therefore generally dosed once per day/ In a trial comparing chronic dosing with bupropion hydrochloride extended-release tablets (SR) 150 mg twice daily to bupropion immediate-release formulation 100 mg 3 times daily, the steady state Cmax for bupropion after bupropion hydrochloride sustained-release tablets (SR) administration was approximately 85% of those achieved after bupropion immediate-release formulation administration. Exposure (AUC) to bupropion was equivalent for both formulations. Bioequivalence was also demonstrated for all three major active metabolites (i.e., hydroxybupropion, threohydrobupropion and erythrohydrobupropion) for both Cmax and AUC. Thus, at steady state, bupropion hydrochloride sustained-release tablets (SR) given twice daily, and the immediate-release formulation of bupropion given 3 times daily, are essentially bioequivalent for both bupropion and the 3 quantitatively important metabolites. Furthermore, in a study comparing 14-day dosing with bupropion hydrochloride extended-release tablets (XL), 300 mg once-daily to the immediate-release formulation of bupropion at 100 mg 3 times daily, equivalence was demonstrated for peak plasma concentration and area under the curve for bupropion and the three metabolites (hydroxybupropion, threohydrobupropion, and erythrohydrobupropion). Additionally, in a study comparing 14-day dosing with bupropion hydrochloride extended-release tablets (XL) 300 mg once daily to the sustained-release formulation of bupropion at 150 mg 2 times daily, equivalence was demonstrated for peak plasma concentration and area under the curve for bupropion and the three metabolites. Bupropion hydrochloride extended-release tablets (SR) can be taken with or without food. Bupropion Cmax and AUC were increased by 11% to 35% and 16% to 19%, respectively, when bupropion hydrochloride extended-release tablets (SR) was administered with food to healthy volunteers in three trials. The food effect is not considered clinically significant. Following a single-dose administration of bupropion hydrochloride extended-release tablets (SR) in humans, Cmax of bupropion's metabolite hydroxybupropion occurs approximately 6 hours post-dose and is approximately 10 times the peak level of the parent drug at steady state. The elimination half-life of hydroxybupropion is approximately 20 (±5) hours and its AUC at steady state is about 17 times that of bupropion. The times to peak concentrations for the erythrohydrobupropion and threohydrobupropion metabolites are similar to that of the hydroxybupropion metabolite. However, their elimination half-lives are longer, 33(±10) and 37 (±13) hours, respectively, and steady-state AUCs are 1.5 and 7 times that of bupropion, respectively. •Absorption (Drug B): Neomycin is poorly absorbed from the gastrointestinal tract. Gastrointestinal absorption of the drug may be increased if inflammatory or ulcerative gastrointestinal disease is present. •Volume of distribution (Drug A): No volume of distribution available •Volume of distribution (Drug B): The small fraction of absorbed neomycin is rapidly distributed in the tissues. The amount of systemically absorbed neomycin is reported to increase cumulatively with each repeated dose administered until a steady state is reached. •Protein binding (Drug A): In vitro tests show that bupropion is 84% bound to human plasma proteins at concentrations up to 200 mcg per mL. The extent of protein binding of the hydroxybupropion metabolite is similar to that for bupropion, whereas the extent of protein binding of the threohydrobupropion metabolite is about half that seen with bupropion. •Protein binding (Drug B): Findings from protein binding studies suggest low protein binding profile for neomycin sulfate, which can range from 0-30% depending on test methods. •Metabolism (Drug A): Bupropion is extensively metabolized in humans. Three metabolites are active: hydroxybupropion, which is formed via hydroxylation of the tert-butyl group of bupropion, and the amino-alcohol isomers, threohydrobupropion and erythrohydrobupropion, which are formed via reduction of the carbonyl group. In vitro findings suggest that CYP2B6 is the principal isoenzyme involved in the formation of hydroxybupropion, while cytochrome P450 enzymes are not involved in the formation of threohydrobupropion. Hydroxybupropion has been shown to have the same affinity as bupropion for the norepinephrine transporter (NET) but approximately 50% of its antidepressant activity despite reaching concentrations of ~10-fold higher than that of the parent drug. Oxidation of the bupropion side chain results in the formation of a glycine conjugate of meta-chlorobenzoic acid, which is then excreted as the major urinary metabolite. The potency and toxicity of the metabolites relative to bupropion have not been fully characterized. However, it has been demonstrated in an antidepressant screening test in mice that hydroxybupropion is one-half as potent as bupropion, while threohydrobupropion and erythrohydrobupropion are 5-fold less potent than bupropion. This may be of clinical importance because the plasma concentrations of the metabolites are as high as or higher than those of bupropion. Bupropion and its metabolites exhibit linear kinetics following chronic administration of 300 to 450 mg per day. •Metabolism (Drug B): There is limited information on the metabolism of neomycin, as there is limited systemic absorption following drug administration. Metabolism is deemed to be negligible. •Route of elimination (Drug A): Bupropion is extensively metabolized in humans. Oxidation of the bupropion side chain results in the formation of a glycine conjugate of metachlorobenzoic acid, which is then excreted as the major urinary metabolite. Following oral administration of 200 mg of 14C-bupropion in humans, 87% and 10% of the radioactive dose were recovered in the urine and feces, respectively. However, the fraction of the oral dose of bupropion excreted unchanged was only 0.5%, a finding consistent with the extensive metabolism of bupropion. •Route of elimination (Drug B): The small absorbed fraction of neomycin is excreted by the kidney. The unabsorbed portion of the drug is excreted unchanged in the feces. •Half-life (Drug A): 24 hours •Half-life (Drug B): There is limited information on the half-life of neomycin. •Clearance (Drug A): No clearance available •Clearance (Drug B): There is limited information on the clearance rate of neomycin. •Toxicity (Drug A): Symptoms of overdose include seizures, hallucinations, loss of consciousness, tachycardia, and cardiac arrest. •Toxicity (Drug B): The oral LD 50 of neomycin sulfate in mouse is > 8 g/kg. The subcutaneous LD 50 is 200 mg/kg in rat and 190 mg/kg in mouse. The intraperitoneal LD 50 in mouse is 305 mg/kg. The oral Lowest published toxic dose (TDLo) in woman is 12600 mg/kg/7D. Because of low absorption, acute overdosage from oral neomycin is not likely to occur. However, prolonged administration of neomycin should be avoided because of the possibility of some systemic absorption and the risk of neurotoxicity, ototoxicity, and/or nephrotoxicity. Hemodialysis will remove neomycin from the blood. While nephrotoxicity and ototoxicity have been reported in otherwise patients without compromised renal function, the risk for developing these toxicities is increased in patients with renal impairment. Like other aminoglycosides, neomycin may cause fetal harm and total irreversible bilateral congenital deafness when administered in pregnant women. •Brand Names (Drug A): Aplenzin, Auvelity, Budeprion, Contrave, Forfivo, Wellbutrin, Zyban •Brand Names (Drug B): Casporyn HC, Cortisporin, Cortisporin-TC, Dioptrol, Diosporin, Diphen, Maxitrol, Neo-polycin, Neo-polycin HC, Neo-synalar, Neosporin Ointment, Neosporin Plus Maximum Strength, Neosporin Plus Maximum Strength Cream, Neosporin Solution, Procomycin, Statrol, Triple Antibiotic, Viaderm Kc •Synonyms (Drug A): No synonyms listed •Synonyms (Drug B): No synonyms listed •Summary (Drug A): Bupropion is a norepinephrine and dopamine reuptake inhibitor used in the treatment of major depressive disorder (MDD), seasonal affective disorder (SAD), and as an aid to smoking cessation. •Summary (Drug B): Neomycin is an aminoglycoside antibiotic agent used orally and topically to treat a wide variety of infections in the body.

The renal excretion of drugs is the overall result of a combination of kidney processes that include glomerular filtration, passive diffusion, tubular secretion, and tubular reabsorption. Since two of these mechanisms - tubular secretion and reabsorption - are saturable processes , they are consequently susceptible to competition between multiple substrates excreted by the kidneys. If two or more medications that are mainly renally excreted are co-administered, they may compete for renal elimination; there is a large likelihood that one agent may "out-compete" or saturate the renal excretion mechanisms before the other concomitantly administered agent(s) are excreted. As a result, the elimination of these other concurrently administered agents may be inhibited or otherwise delayed, which could lead to increases in their serum concentrations and the risk, incidence, and/or severity of adverse effects associated with the exposure to such drugs. The affected drug is a narrow therapeutic index drug that undergoes renal excretion as its main elimination pathway: a change in serum concentration may significantly elevate the risk of developing drug-related adverse effects. The severity of the interaction is moderate.

Question: Does Bupropion and Neomycin interact? Information: •Drug A: Bupropion •Drug B: Neomycin •Severity: MODERATE •Description: Bupropion may decrease the excretion rate of Neomycin which could result in a higher serum level. •Extended Description: The renal excretion of drugs is the overall result of a combination of kidney processes that include glomerular filtration, passive diffusion, tubular secretion, and tubular reabsorption. Since two of these mechanisms - tubular secretion and reabsorption - are saturable processes , they are consequently susceptible to competition between multiple substrates excreted by the kidneys. If two or more medications that are mainly renally excreted are co-administered, they may compete for renal elimination; there is a large likelihood that one agent may "out-compete" or saturate the renal excretion mechanisms before the other concomitantly administered agent(s) are excreted. As a result, the elimination of these other concurrently administered agents may be inhibited or otherwise delayed, which could lead to increases in their serum concentrations and the risk, incidence, and/or severity of adverse effects associated with the exposure to such drugs. The affected drug is a narrow therapeutic index drug that undergoes renal excretion as its main elimination pathway: a change in serum concentration may significantly elevate the risk of developing drug-related adverse effects. •Indication (Drug A): Bupropion is indicated for the treatment of major depressive disorder (MDD), seasonal affective disorder (SAD), and as an aid to smoking cessation. When used in combination with naltrexone as the marketed product ContraveⓇ, bupropion is indicated as an adjunct to a reduced-calorie diet and increased physical activity for chronic weight management in adults with an initial body mass index (BMI) of: 30 kg/m^2 or greater (obese) or 27 kg/m^2 or greater (overweight) in the presence of at least one weight-related comorbid condition (e.g., hypertension, type 2 diabetes mellitus, or dyslipidemia). Bupropion is also used off-label as a first-line treatment in patients with ADHD and comorbid bipolar disorder when used as an adjunct to mood stabilizers. •Indication (Drug B): Oral neomycin sulfate is indicated as an adjunctive therapy in hepatic coma (portal-system encephalopathy) by reducing ammonia-forming bacteria in the intestinal tract. It is strongly recommended that oral neomycin is only used in infections that are proven or strongly suspected to be caused by susceptible bacteria to reduce the risk of the development of drug-resistant bacteria. Neomycin, in combination with polymyxin B sulfates and hydrocortisone in otic suspensions, is used in the treatment of superficial bacterial infections of the external auditory canal caused by organisms susceptible to the antibiotics. This otic formulation is also used in the treatment of infections of mastoidectomy and fenestration cavities caused by organisms susceptible to the antibiotics. The ophthalmic solution containing neomycin in combination with polymyxin B sulfates and dexamethasone is used to treat steroid-responsive inflammatory ocular conditions for which a corticosteroid is indicated and where bacterial infection or a risk of bacterial infection exists. •Pharmacodynamics (Drug A): Bupropion is chemically unrelated to tricyclic, tetracyclic, selective serotonin re-uptake inhibitors, or other known antidepressant agents. Compared to classical tricyclic antidepressants, Bupropion is a relatively weak inhibitor of the neuronal uptake of norepinephrine and dopamine. In addition, Bupropion does not inhibit monoamine oxidase. Bupropion has been found to be essentially inactive at the serotonin transporter (SERT)(IC50 >10 000 nM), however both bupropion and its primary metabolite hydroxybupropion have been found to block the function of cation-selective serotonin type 3A receptors (5-HT3ARs). Bupropion produces dose-related central nervous system (CNS) stimulant effects in animals, as evidenced by increased locomotor activity, increased rates of responding in various schedule-controlled operant behaviour tasks, and, at high doses, induction of mild stereotyped behaviour. Due to these stimulant effects and selective activity at dopamine and norepinephrine receptors, bupropion has been identified as having an abuse potential. Bupropion has a similar structure to the controlled substance Cathinone, and has been identified as having mild amphetamine-like activity, particularly when inhaled or injected. Bupropion is also known to lower the seizure threshold, making any pre-existing seizure conditions a contraindication to its use. This risk is exacerbated when bupropion is combined with other drugs or substances that lower the seizure threshold, such as cocaine, or in clinical situations that would increase the risk of a seizure such as abrupt alcohol or benzodiazepine withdrawal. As norepinephrine has been shown to have anticonvulsant properties, bupropion's inhibitory effects on NET are thought to contribute to its pro-convulsant activity. Bupropion has been shown to increase blood pressure and pose a risk for exacerbation of unmanaged or pre-existing hypertension, however, clinical trials of bupropion in smokers with CVD have not identified an increased incidence of CV events including stroke or heart attack. In clinical trials, the mean increase in systolic blood pressure associated with the use of bupropion was found to be 1.3 mmHg. •Pharmacodynamics (Drug B): Neomycin mediates its bactericidal action by inhibiting bacterial protein synthesis, thereby suppressing the growth and survival of susceptible bacteria. Following oral administration, the duration of bactericidal activity of neomycin ranged from 48 to 72 hours. By decreasing colonic bacteria that produce ammonia, neomycin was shown to be effective as an adjunctive therapy in hepatic coma to improve neurologic symptoms. Neomycin is active against both gram positive and gram negative organisms, including the major E. coli species resident in the colon as well as the enteropathogenic forms of E. coli. It is also active against Klebsiella - Enterobacter group. Resistant strains of E. coli, Klebsiella and Proteus spp. may emerge from neomycin therapy. Neomycin has no antifungal activity and has some activity against some protozoa. •Mechanism of action (Drug A): Bupropion is a norepinephrine/dopamine-reuptake inhibitor (NDRI) that exerts its pharmacological effects by weakly inhibiting the enzymes involved in the uptake of the neurotransmitters norepinephrine and dopamine from the synaptic cleft, therefore prolonging their duration of action within the neuronal synapse and the downstream effects of these neurotransmitters. More specifically, bupropion binds to the norepinephrine transporter (NET) and the dopamine transporter (DAT). Bupropion was originally classified as an "atypical" antidepressant because it does not exert the same effects as the classical antidepressants such as Monoamine Oxidase Inhibitors (MAOIs), Tricyclic Antidepressants (TCAs), or Selective Serotonin Reuptake Inhibitors (SSRIs). While it has comparable effectiveness to typical first-line options for the treatment of depression such as SSRIs, bupropion is a unique option for the treatment of MDD as it lacks any clinically relevant serotonergic effects, typical of other mood medications, or any effects on histamine or adrenaline receptors. Lack of activity at these receptors results in a more tolerable side effect profile; bupropion is less likely to cause sexual side effects, sedation, or weight gain as compared to SSRIs or TCAs, for example. When used as an aid to smoking cessation, bupropion is thought to confer its anti-craving and anti-withdrawal effects by inhibiting dopamine reuptake, which is thought to be involved in the reward pathways associated with nicotine, and through the antagonism of the nicotinic acetylcholinergic receptor (AChR), thereby blunting the effects of nicotine. Furthermore, the stimulatory effects produced by bupropion in the central nervous system are similar to nicotine's effects, making low doses of bupropion a suitable option as a nicotine substitute. When used in combination with naltrexone in the marketed product ContraveⓇ for chronic weight management, the two components are thought to have effects on areas of the brain involved in the regulation of food intake. This includes the hypothalamus, which is involved in appetite regulation, and the mesolimbic dopamine circuit, which is involved in reward pathways. Studies have shown that the combined activity of bupropion and naltrexone increase the firing rate of hypothalamic pro-opiomelanocortin (POMC) neurons and blockade of opioid receptor-mediated POMC auto-inhibition, which are associated with a reduction in food intake and increased energy expenditure. This combination was also found to reduce food intake when injected directly into the ventral tegmental area of the mesolimbic circuit in mice, which is an area associated with the regulation of reward pathways. •Mechanism of action (Drug B): Like other aminoglycoside antibiotic drugs, neomycin inhibits bacterial ribosomes by binding to the 30S ribosomal subunit of susceptible bacteria and disrupting the translational machinery of bacterial protein synthesis. Bacterial translation is normally initiated by the mRNA binding to the 30S ribosomal subunit and subsequent binding with 50S subunit for elongation. •Absorption (Drug A): Bupropion is currently available in 3 distinct, but bioequivalent formulations: immediate release (IR), sustained-release (SR), and extended-release (XL). Immediate Release Formulation In humans, following oral administration of bupropion hydrochloride tablets, peak plasma bupropion concentrations are usually achieved within 2 hours. IR formulations provide a short duration of action and are therefore generally dosed three times per day. Sustained Release Formulation In humans, following oral administration of bupropion hydrochloride sustained-release tablets (SR), peak plasma concentration (Cmax) of bupropion is usually achieved within 3 hours. SR formulations provide a 12-hour extended release of medication and are therefore generally dosed twice per day. Extended Release Formulation Following single oral administration of bupropion hydrochloride extended-release tablets (XL) to healthy volunteers, the median time to peak plasma concentrations for bupropion was approximately 5 hours. The presence of food did not affect the peak concentration or area under the curve of bupropion. XL formulations provide a 24-hour extended release of medication and are therefore generally dosed once per day/ In a trial comparing chronic dosing with bupropion hydrochloride extended-release tablets (SR) 150 mg twice daily to bupropion immediate-release formulation 100 mg 3 times daily, the steady state Cmax for bupropion after bupropion hydrochloride sustained-release tablets (SR) administration was approximately 85% of those achieved after bupropion immediate-release formulation administration. Exposure (AUC) to bupropion was equivalent for both formulations. Bioequivalence was also demonstrated for all three major active metabolites (i.e., hydroxybupropion, threohydrobupropion and erythrohydrobupropion) for both Cmax and AUC. Thus, at steady state, bupropion hydrochloride sustained-release tablets (SR) given twice daily, and the immediate-release formulation of bupropion given 3 times daily, are essentially bioequivalent for both bupropion and the 3 quantitatively important metabolites. Furthermore, in a study comparing 14-day dosing with bupropion hydrochloride extended-release tablets (XL), 300 mg once-daily to the immediate-release formulation of bupropion at 100 mg 3 times daily, equivalence was demonstrated for peak plasma concentration and area under the curve for bupropion and the three metabolites (hydroxybupropion, threohydrobupropion, and erythrohydrobupropion). Additionally, in a study comparing 14-day dosing with bupropion hydrochloride extended-release tablets (XL) 300 mg once daily to the sustained-release formulation of bupropion at 150 mg 2 times daily, equivalence was demonstrated for peak plasma concentration and area under the curve for bupropion and the three metabolites. Bupropion hydrochloride extended-release tablets (SR) can be taken with or without food. Bupropion Cmax and AUC were increased by 11% to 35% and 16% to 19%, respectively, when bupropion hydrochloride extended-release tablets (SR) was administered with food to healthy volunteers in three trials. The food effect is not considered clinically significant. Following a single-dose administration of bupropion hydrochloride extended-release tablets (SR) in humans, Cmax of bupropion's metabolite hydroxybupropion occurs approximately 6 hours post-dose and is approximately 10 times the peak level of the parent drug at steady state. The elimination half-life of hydroxybupropion is approximately 20 (±5) hours and its AUC at steady state is about 17 times that of bupropion. The times to peak concentrations for the erythrohydrobupropion and threohydrobupropion metabolites are similar to that of the hydroxybupropion metabolite. However, their elimination half-lives are longer, 33(±10) and 37 (±13) hours, respectively, and steady-state AUCs are 1.5 and 7 times that of bupropion, respectively. •Absorption (Drug B): Neomycin is poorly absorbed from the gastrointestinal tract. Gastrointestinal absorption of the drug may be increased if inflammatory or ulcerative gastrointestinal disease is present. •Volume of distribution (Drug A): No volume of distribution available •Volume of distribution (Drug B): The small fraction of absorbed neomycin is rapidly distributed in the tissues. The amount of systemically absorbed neomycin is reported to increase cumulatively with each repeated dose administered until a steady state is reached. •Protein binding (Drug A): In vitro tests show that bupropion is 84% bound to human plasma proteins at concentrations up to 200 mcg per mL. The extent of protein binding of the hydroxybupropion metabolite is similar to that for bupropion, whereas the extent of protein binding of the threohydrobupropion metabolite is about half that seen with bupropion. •Protein binding (Drug B): Findings from protein binding studies suggest low protein binding profile for neomycin sulfate, which can range from 0-30% depending on test methods. •Metabolism (Drug A): Bupropion is extensively metabolized in humans. Three metabolites are active: hydroxybupropion, which is formed via hydroxylation of the tert-butyl group of bupropion, and the amino-alcohol isomers, threohydrobupropion and erythrohydrobupropion, which are formed via reduction of the carbonyl group. In vitro findings suggest that CYP2B6 is the principal isoenzyme involved in the formation of hydroxybupropion, while cytochrome P450 enzymes are not involved in the formation of threohydrobupropion. Hydroxybupropion has been shown to have the same affinity as bupropion for the norepinephrine transporter (NET) but approximately 50% of its antidepressant activity despite reaching concentrations of ~10-fold higher than that of the parent drug. Oxidation of the bupropion side chain results in the formation of a glycine conjugate of meta-chlorobenzoic acid, which is then excreted as the major urinary metabolite. The potency and toxicity of the metabolites relative to bupropion have not been fully characterized. However, it has been demonstrated in an antidepressant screening test in mice that hydroxybupropion is one-half as potent as bupropion, while threohydrobupropion and erythrohydrobupropion are 5-fold less potent than bupropion. This may be of clinical importance because the plasma concentrations of the metabolites are as high as or higher than those of bupropion. Bupropion and its metabolites exhibit linear kinetics following chronic administration of 300 to 450 mg per day. •Metabolism (Drug B): There is limited information on the metabolism of neomycin, as there is limited systemic absorption following drug administration. Metabolism is deemed to be negligible. •Route of elimination (Drug A): Bupropion is extensively metabolized in humans. Oxidation of the bupropion side chain results in the formation of a glycine conjugate of metachlorobenzoic acid, which is then excreted as the major urinary metabolite. Following oral administration of 200 mg of 14C-bupropion in humans, 87% and 10% of the radioactive dose were recovered in the urine and feces, respectively. However, the fraction of the oral dose of bupropion excreted unchanged was only 0.5%, a finding consistent with the extensive metabolism of bupropion. •Route of elimination (Drug B): The small absorbed fraction of neomycin is excreted by the kidney. The unabsorbed portion of the drug is excreted unchanged in the feces. •Half-life (Drug A): 24 hours •Half-life (Drug B): There is limited information on the half-life of neomycin. •Clearance (Drug A): No clearance available •Clearance (Drug B): There is limited information on the clearance rate of neomycin. •Toxicity (Drug A): Symptoms of overdose include seizures, hallucinations, loss of consciousness, tachycardia, and cardiac arrest. •Toxicity (Drug B): The oral LD 50 of neomycin sulfate in mouse is > 8 g/kg. The subcutaneous LD 50 is 200 mg/kg in rat and 190 mg/kg in mouse. The intraperitoneal LD 50 in mouse is 305 mg/kg. The oral Lowest published toxic dose (TDLo) in woman is 12600 mg/kg/7D. Because of low absorption, acute overdosage from oral neomycin is not likely to occur. However, prolonged administration of neomycin should be avoided because of the possibility of some systemic absorption and the risk of neurotoxicity, ototoxicity, and/or nephrotoxicity. Hemodialysis will remove neomycin from the blood. While nephrotoxicity and ototoxicity have been reported in otherwise patients without compromised renal function, the risk for developing these toxicities is increased in patients with renal impairment. Like other aminoglycosides, neomycin may cause fetal harm and total irreversible bilateral congenital deafness when administered in pregnant women. •Brand Names (Drug A): Aplenzin, Auvelity, Budeprion, Contrave, Forfivo, Wellbutrin, Zyban •Brand Names (Drug B): Casporyn HC, Cortisporin, Cortisporin-TC, Dioptrol, Diosporin, Diphen, Maxitrol, Neo-polycin, Neo-polycin HC, Neo-synalar, Neosporin Ointment, Neosporin Plus Maximum Strength, Neosporin Plus Maximum Strength Cream, Neosporin Solution, Procomycin, Statrol, Triple Antibiotic, Viaderm Kc •Synonyms (Drug A): No synonyms listed •Synonyms (Drug B): No synonyms listed •Summary (Drug A): Bupropion is a norepinephrine and dopamine reuptake inhibitor used in the treatment of major depressive disorder (MDD), seasonal affective disorder (SAD), and as an aid to smoking cessation. •Summary (Drug B): Neomycin is an aminoglycoside antibiotic agent used orally and topically to treat a wide variety of infections in the body. Output: The renal excretion of drugs is the overall result of a combination of kidney processes that include glomerular filtration, passive diffusion, tubular secretion, and tubular reabsorption. Since two of these mechanisms - tubular secretion and reabsorption - are saturable processes , they are consequently susceptible to competition between multiple substrates excreted by the kidneys. If two or more medications that are mainly renally excreted are co-administered, they may compete for renal elimination; there is a large likelihood that one agent may "out-compete" or saturate the renal excretion mechanisms before the other concomitantly administered agent(s) are excreted. As a result, the elimination of these other concurrently administered agents may be inhibited or otherwise delayed, which could lead to increases in their serum concentrations and the risk, incidence, and/or severity of adverse effects associated with the exposure to such drugs. The affected drug is a narrow therapeutic index drug that undergoes renal excretion as its main elimination pathway: a change in serum concentration may significantly elevate the risk of developing drug-related adverse effects. The severity of the interaction is moderate.

Does Bupropion and Netilmicin interact?

•Drug A: Bupropion •Drug B: Netilmicin •Severity: MODERATE •Description: Bupropion may decrease the excretion rate of Netilmicin which could result in a higher serum level. •Extended Description: The renal excretion of drugs is the overall result of a combination of kidney processes that include glomerular filtration, passive diffusion, tubular secretion, and tubular reabsorption. Since two of these mechanisms - tubular secretion and reabsorption - are saturable processes , they are consequently susceptible to competition between multiple substrates excreted by the kidneys. If two or more medications that are mainly renally excreted are co-administered, they may compete for renal elimination; there is a large likelihood that one agent may "out-compete" or saturate the renal excretion mechanisms before the other concomitantly administered agent(s) are excreted. As a result, the elimination of these other concurrently administered agents may be inhibited or otherwise delayed, which could lead to increases in their serum concentrations and the risk, incidence, and/or severity of adverse effects associated with the exposure to such drugs. The affected drug is a narrow therapeutic index drug that undergoes renal excretion as its main elimination pathway: a change in serum concentration may significantly elevate the risk of developing drug-related adverse effects. •Indication (Drug A): Bupropion is indicated for the treatment of major depressive disorder (MDD), seasonal affective disorder (SAD), and as an aid to smoking cessation. When used in combination with naltrexone as the marketed product ContraveⓇ, bupropion is indicated as an adjunct to a reduced-calorie diet and increased physical activity for chronic weight management in adults with an initial body mass index (BMI) of: 30 kg/m^2 or greater (obese) or 27 kg/m^2 or greater (overweight) in the presence of at least one weight-related comorbid condition (e.g., hypertension, type 2 diabetes mellitus, or dyslipidemia). Bupropion is also used off-label as a first-line treatment in patients with ADHD and comorbid bipolar disorder when used as an adjunct to mood stabilizers. •Indication (Drug B): For the treatment of bacteremia, septicaemia, respiratory tract infections, skin and soft-tissue infection, burns, wounds, and peri-operative infections caused by susceptible strains. •Pharmacodynamics (Drug A): Bupropion is chemically unrelated to tricyclic, tetracyclic, selective serotonin re-uptake inhibitors, or other known antidepressant agents. Compared to classical tricyclic antidepressants, Bupropion is a relatively weak inhibitor of the neuronal uptake of norepinephrine and dopamine. In addition, Bupropion does not inhibit monoamine oxidase. Bupropion has been found to be essentially inactive at the serotonin transporter (SERT)(IC50 >10 000 nM), however both bupropion and its primary metabolite hydroxybupropion have been found to block the function of cation-selective serotonin type 3A receptors (5-HT3ARs). Bupropion produces dose-related central nervous system (CNS) stimulant effects in animals, as evidenced by increased locomotor activity, increased rates of responding in various schedule-controlled operant behaviour tasks, and, at high doses, induction of mild stereotyped behaviour. Due to these stimulant effects and selective activity at dopamine and norepinephrine receptors, bupropion has been identified as having an abuse potential. Bupropion has a similar structure to the controlled substance Cathinone, and has been identified as having mild amphetamine-like activity, particularly when inhaled or injected. Bupropion is also known to lower the seizure threshold, making any pre-existing seizure conditions a contraindication to its use. This risk is exacerbated when bupropion is combined with other drugs or substances that lower the seizure threshold, such as cocaine, or in clinical situations that would increase the risk of a seizure such as abrupt alcohol or benzodiazepine withdrawal. As norepinephrine has been shown to have anticonvulsant properties, bupropion's inhibitory effects on NET are thought to contribute to its pro-convulsant activity. Bupropion has been shown to increase blood pressure and pose a risk for exacerbation of unmanaged or pre-existing hypertension, however, clinical trials of bupropion in smokers with CVD have not identified an increased incidence of CV events including stroke or heart attack. In clinical trials, the mean increase in systolic blood pressure associated with the use of bupropion was found to be 1.3 mmHg. •Pharmacodynamics (Drug B): Netilmicin is a semisynthetic, water soluble antibiotic of the aminoglycoside group, produced by the fermentation of Micromonospora inyoensis, a species of actinomycete. Aminoglycosides are useful primarily in infections involving aerobic, Gram-negative bacteria, such as Pseudomonas, Acinetobacter, and Enterobacter. It is active at low concentrations against a wide variety of pathogenic bacteria including Escherichia coli, bacteria of the Klebsiella-Enterobacter-Serratia group, Citrobacter sp., Proteus sp. (indole-positive and indole-negative), including Proteus mirabilis, P. morganii, P. rettgrei, P. vulgaris, Pseudomonas aeruginosa and Neisseria gonorrhoea. Netilmicin is also active in vitro against isolates of Hemophilus influenzae, Salmonella sp., Shigella sp. and against penicillinase and non-penicillinase-producing Staphylococcus including methicillin-resistant strains. Some strains of Providencia sp., Acinetobacter sp. and Aeromonas sp. are also sensitive to netilmicin. Many strains of the above organisms which are found to be resistant to other aminoglycosides, such as kanamycin, gentamicin, tobramycin and sisomicin, are susceptible to netilmicin in vitro. Occasionally, strains have been identified which are resistant to amikacin but susceptible to netilmicin. The combination of netilmicin and penicillin G has a synergistic bactericidal effect against most strains of Streptococcus faecalis (enterococcus). The combined effect of netilmicin and carbenicillin or ticarcillin is synergistic for many strains of Pseudomonas aeruginosa. In addition, many isolates of Serratia, which are resistant to multiple antibiotics, are inhibited by synergistic combinations of netilmicin with carbenicillin, azlocillin, mezlocillin, cefamandole, cefotaxime or moxalactam. Aminoglycosides are mostly ineffective against anaerobic bacteria, fungi and viruses. •Mechanism of action (Drug A): Bupropion is a norepinephrine/dopamine-reuptake inhibitor (NDRI) that exerts its pharmacological effects by weakly inhibiting the enzymes involved in the uptake of the neurotransmitters norepinephrine and dopamine from the synaptic cleft, therefore prolonging their duration of action within the neuronal synapse and the downstream effects of these neurotransmitters. More specifically, bupropion binds to the norepinephrine transporter (NET) and the dopamine transporter (DAT). Bupropion was originally classified as an "atypical" antidepressant because it does not exert the same effects as the classical antidepressants such as Monoamine Oxidase Inhibitors (MAOIs), Tricyclic Antidepressants (TCAs), or Selective Serotonin Reuptake Inhibitors (SSRIs). While it has comparable effectiveness to typical first-line options for the treatment of depression such as SSRIs, bupropion is a unique option for the treatment of MDD as it lacks any clinically relevant serotonergic effects, typical of other mood medications, or any effects on histamine or adrenaline receptors. Lack of activity at these receptors results in a more tolerable side effect profile; bupropion is less likely to cause sexual side effects, sedation, or weight gain as compared to SSRIs or TCAs, for example. When used as an aid to smoking cessation, bupropion is thought to confer its anti-craving and anti-withdrawal effects by inhibiting dopamine reuptake, which is thought to be involved in the reward pathways associated with nicotine, and through the antagonism of the nicotinic acetylcholinergic receptor (AChR), thereby blunting the effects of nicotine. Furthermore, the stimulatory effects produced by bupropion in the central nervous system are similar to nicotine's effects, making low doses of bupropion a suitable option as a nicotine substitute. When used in combination with naltrexone in the marketed product ContraveⓇ for chronic weight management, the two components are thought to have effects on areas of the brain involved in the regulation of food intake. This includes the hypothalamus, which is involved in appetite regulation, and the mesolimbic dopamine circuit, which is involved in reward pathways. Studies have shown that the combined activity of bupropion and naltrexone increase the firing rate of hypothalamic pro-opiomelanocortin (POMC) neurons and blockade of opioid receptor-mediated POMC auto-inhibition, which are associated with a reduction in food intake and increased energy expenditure. This combination was also found to reduce food intake when injected directly into the ventral tegmental area of the mesolimbic circuit in mice, which is an area associated with the regulation of reward pathways. •Mechanism of action (Drug B): Aminoglycosides like netilmicin "irreversibly" bind to specific 30S-subunit proteins and 16S rRNA. Specifically netilmicin binds to four nucleotides of 16S rRNA and a single amino acid of protein S12. This interferes with decoding site in the vicinity of nucleotide 1400 in 16S rRNA of 30S subunit. This region interacts with the wobble base in the anticodon of tRNA. This leads to interference with the initiation complex, misreading of mRNA so incorrect amino acids are inserted into the polypeptide leading to nonfunctional or toxic peptides and the breakup of polysomes into nonfunctional monosomes, leaving the bacterium unable to synthesize proteins vital to its growth. •Absorption (Drug A): Bupropion is currently available in 3 distinct, but bioequivalent formulations: immediate release (IR), sustained-release (SR), and extended-release (XL). Immediate Release Formulation In humans, following oral administration of bupropion hydrochloride tablets, peak plasma bupropion concentrations are usually achieved within 2 hours. IR formulations provide a short duration of action and are therefore generally dosed three times per day. Sustained Release Formulation In humans, following oral administration of bupropion hydrochloride sustained-release tablets (SR), peak plasma concentration (Cmax) of bupropion is usually achieved within 3 hours. SR formulations provide a 12-hour extended release of medication and are therefore generally dosed twice per day. Extended Release Formulation Following single oral administration of bupropion hydrochloride extended-release tablets (XL) to healthy volunteers, the median time to peak plasma concentrations for bupropion was approximately 5 hours. The presence of food did not affect the peak concentration or area under the curve of bupropion. XL formulations provide a 24-hour extended release of medication and are therefore generally dosed once per day/ In a trial comparing chronic dosing with bupropion hydrochloride extended-release tablets (SR) 150 mg twice daily to bupropion immediate-release formulation 100 mg 3 times daily, the steady state Cmax for bupropion after bupropion hydrochloride sustained-release tablets (SR) administration was approximately 85% of those achieved after bupropion immediate-release formulation administration. Exposure (AUC) to bupropion was equivalent for both formulations. Bioequivalence was also demonstrated for all three major active metabolites (i.e., hydroxybupropion, threohydrobupropion and erythrohydrobupropion) for both Cmax and AUC. Thus, at steady state, bupropion hydrochloride sustained-release tablets (SR) given twice daily, and the immediate-release formulation of bupropion given 3 times daily, are essentially bioequivalent for both bupropion and the 3 quantitatively important metabolites. Furthermore, in a study comparing 14-day dosing with bupropion hydrochloride extended-release tablets (XL), 300 mg once-daily to the immediate-release formulation of bupropion at 100 mg 3 times daily, equivalence was demonstrated for peak plasma concentration and area under the curve for bupropion and the three metabolites (hydroxybupropion, threohydrobupropion, and erythrohydrobupropion). Additionally, in a study comparing 14-day dosing with bupropion hydrochloride extended-release tablets (XL) 300 mg once daily to the sustained-release formulation of bupropion at 150 mg 2 times daily, equivalence was demonstrated for peak plasma concentration and area under the curve for bupropion and the three metabolites. Bupropion hydrochloride extended-release tablets (SR) can be taken with or without food. Bupropion Cmax and AUC were increased by 11% to 35% and 16% to 19%, respectively, when bupropion hydrochloride extended-release tablets (SR) was administered with food to healthy volunteers in three trials. The food effect is not considered clinically significant. Following a single-dose administration of bupropion hydrochloride extended-release tablets (SR) in humans, Cmax of bupropion's metabolite hydroxybupropion occurs approximately 6 hours post-dose and is approximately 10 times the peak level of the parent drug at steady state. The elimination half-life of hydroxybupropion is approximately 20 (±5) hours and its AUC at steady state is about 17 times that of bupropion. The times to peak concentrations for the erythrohydrobupropion and threohydrobupropion metabolites are similar to that of the hydroxybupropion metabolite. However, their elimination half-lives are longer, 33(±10) and 37 (±13) hours, respectively, and steady-state AUCs are 1.5 and 7 times that of bupropion, respectively. •Absorption (Drug B): Rapidly and completely absorbed after IM administration, peak serum levels were achieved within 30-60 minutes. Aminoglycosides are poorly absorbed orally. Topical absorption is also poor unless severe skin damage is present. •Volume of distribution (Drug A): No volume of distribution available •Volume of distribution (Drug B): No volume of distribution available •Protein binding (Drug A): In vitro tests show that bupropion is 84% bound to human plasma proteins at concentrations up to 200 mcg per mL. The extent of protein binding of the hydroxybupropion metabolite is similar to that for bupropion, whereas the extent of protein binding of the threohydrobupropion metabolite is about half that seen with bupropion. •Protein binding (Drug B): Protein-binding of is low and depends on the test conditions (mainly the concentration of cations in the test medium). •Metabolism (Drug A): Bupropion is extensively metabolized in humans. Three metabolites are active: hydroxybupropion, which is formed via hydroxylation of the tert-butyl group of bupropion, and the amino-alcohol isomers, threohydrobupropion and erythrohydrobupropion, which are formed via reduction of the carbonyl group. In vitro findings suggest that CYP2B6 is the principal isoenzyme involved in the formation of hydroxybupropion, while cytochrome P450 enzymes are not involved in the formation of threohydrobupropion. Hydroxybupropion has been shown to have the same affinity as bupropion for the norepinephrine transporter (NET) but approximately 50% of its antidepressant activity despite reaching concentrations of ~10-fold higher than that of the parent drug. Oxidation of the bupropion side chain results in the formation of a glycine conjugate of meta-chlorobenzoic acid, which is then excreted as the major urinary metabolite. The potency and toxicity of the metabolites relative to bupropion have not been fully characterized. However, it has been demonstrated in an antidepressant screening test in mice that hydroxybupropion is one-half as potent as bupropion, while threohydrobupropion and erythrohydrobupropion are 5-fold less potent than bupropion. This may be of clinical importance because the plasma concentrations of the metabolites are as high as or higher than those of bupropion. Bupropion and its metabolites exhibit linear kinetics following chronic administration of 300 to 450 mg per day. •Metabolism (Drug B): No evidence of metabolic transformation, typically 80% is recoverable in the urine within 24 hours •Route of elimination (Drug A): Bupropion is extensively metabolized in humans. Oxidation of the bupropion side chain results in the formation of a glycine conjugate of metachlorobenzoic acid, which is then excreted as the major urinary metabolite. Following oral administration of 200 mg of 14C-bupropion in humans, 87% and 10% of the radioactive dose were recovered in the urine and feces, respectively. However, the fraction of the oral dose of bupropion excreted unchanged was only 0.5%, a finding consistent with the extensive metabolism of bupropion. •Route of elimination (Drug B): No route of elimination available •Half-life (Drug A): 24 hours •Half-life (Drug B): 2.5 hours •Clearance (Drug A): No clearance available •Clearance (Drug B): No clearance available •Toxicity (Drug A): Symptoms of overdose include seizures, hallucinations, loss of consciousness, tachycardia, and cardiac arrest. •Toxicity (Drug B): Netilmicin has nephrotoxic and ototoxic potential. Nephrotoxicity occurs via drug accumulation in renal proximal tubular cells resulting in cellular damage. Tubular cells may regenerate despite continued exposure and nephrotoxicity is usually mild and reversible. Netilmicin is less nephrotoxic than neomycin, gentamicin, tobramycin, and amikacin, likely due to a reduced number of cationic amino groups in its structure. Otoxicity occurs as a result of irreversible damage to hair cells of the cochlea and/or summit of the ampullar cristae in the vestibular complex caused drug accumulation in the endolymph and perilymph of the inner ear. Otoxicity appears to be correlated to total exposure and may be cumulative with further doses of aminoglycosides or other ototoxic drugs (e.g. cisplatin, furosemide). High frequency hearing loss is followed by low frequency hearing loss, which may be followed by retrograde degeneration of the auditory nerve. Vestibular toxicity may cause vertigo, nausea and vomiting, dizziness and loss of balance. •Brand Names (Drug A): Aplenzin, Auvelity, Budeprion, Contrave, Forfivo, Wellbutrin, Zyban •Brand Names (Drug B): No brand names available •Synonyms (Drug A): No synonyms listed •Synonyms (Drug B): No synonyms listed •Summary (Drug A): Bupropion is a norepinephrine and dopamine reuptake inhibitor used in the treatment of major depressive disorder (MDD), seasonal affective disorder (SAD), and as an aid to smoking cessation. •Summary (Drug B): Netilmicin is an aminoglycoside used to treat a wide variety of infections in the body.

The renal excretion of drugs is the overall result of a combination of kidney processes that include glomerular filtration, passive diffusion, tubular secretion, and tubular reabsorption. Since two of these mechanisms - tubular secretion and reabsorption - are saturable processes , they are consequently susceptible to competition between multiple substrates excreted by the kidneys. If two or more medications that are mainly renally excreted are co-administered, they may compete for renal elimination; there is a large likelihood that one agent may "out-compete" or saturate the renal excretion mechanisms before the other concomitantly administered agent(s) are excreted. As a result, the elimination of these other concurrently administered agents may be inhibited or otherwise delayed, which could lead to increases in their serum concentrations and the risk, incidence, and/or severity of adverse effects associated with the exposure to such drugs. The affected drug is a narrow therapeutic index drug that undergoes renal excretion as its main elimination pathway: a change in serum concentration may significantly elevate the risk of developing drug-related adverse effects. The severity of the interaction is moderate.

Question: Does Bupropion and Netilmicin interact? Information: •Drug A: Bupropion •Drug B: Netilmicin •Severity: MODERATE •Description: Bupropion may decrease the excretion rate of Netilmicin which could result in a higher serum level. •Extended Description: The renal excretion of drugs is the overall result of a combination of kidney processes that include glomerular filtration, passive diffusion, tubular secretion, and tubular reabsorption. Since two of these mechanisms - tubular secretion and reabsorption - are saturable processes , they are consequently susceptible to competition between multiple substrates excreted by the kidneys. If two or more medications that are mainly renally excreted are co-administered, they may compete for renal elimination; there is a large likelihood that one agent may "out-compete" or saturate the renal excretion mechanisms before the other concomitantly administered agent(s) are excreted. As a result, the elimination of these other concurrently administered agents may be inhibited or otherwise delayed, which could lead to increases in their serum concentrations and the risk, incidence, and/or severity of adverse effects associated with the exposure to such drugs. The affected drug is a narrow therapeutic index drug that undergoes renal excretion as its main elimination pathway: a change in serum concentration may significantly elevate the risk of developing drug-related adverse effects. •Indication (Drug A): Bupropion is indicated for the treatment of major depressive disorder (MDD), seasonal affective disorder (SAD), and as an aid to smoking cessation. When used in combination with naltrexone as the marketed product ContraveⓇ, bupropion is indicated as an adjunct to a reduced-calorie diet and increased physical activity for chronic weight management in adults with an initial body mass index (BMI) of: 30 kg/m^2 or greater (obese) or 27 kg/m^2 or greater (overweight) in the presence of at least one weight-related comorbid condition (e.g., hypertension, type 2 diabetes mellitus, or dyslipidemia). Bupropion is also used off-label as a first-line treatment in patients with ADHD and comorbid bipolar disorder when used as an adjunct to mood stabilizers. •Indication (Drug B): For the treatment of bacteremia, septicaemia, respiratory tract infections, skin and soft-tissue infection, burns, wounds, and peri-operative infections caused by susceptible strains. •Pharmacodynamics (Drug A): Bupropion is chemically unrelated to tricyclic, tetracyclic, selective serotonin re-uptake inhibitors, or other known antidepressant agents. Compared to classical tricyclic antidepressants, Bupropion is a relatively weak inhibitor of the neuronal uptake of norepinephrine and dopamine. In addition, Bupropion does not inhibit monoamine oxidase. Bupropion has been found to be essentially inactive at the serotonin transporter (SERT)(IC50 >10 000 nM), however both bupropion and its primary metabolite hydroxybupropion have been found to block the function of cation-selective serotonin type 3A receptors (5-HT3ARs). Bupropion produces dose-related central nervous system (CNS) stimulant effects in animals, as evidenced by increased locomotor activity, increased rates of responding in various schedule-controlled operant behaviour tasks, and, at high doses, induction of mild stereotyped behaviour. Due to these stimulant effects and selective activity at dopamine and norepinephrine receptors, bupropion has been identified as having an abuse potential. Bupropion has a similar structure to the controlled substance Cathinone, and has been identified as having mild amphetamine-like activity, particularly when inhaled or injected. Bupropion is also known to lower the seizure threshold, making any pre-existing seizure conditions a contraindication to its use. This risk is exacerbated when bupropion is combined with other drugs or substances that lower the seizure threshold, such as cocaine, or in clinical situations that would increase the risk of a seizure such as abrupt alcohol or benzodiazepine withdrawal. As norepinephrine has been shown to have anticonvulsant properties, bupropion's inhibitory effects on NET are thought to contribute to its pro-convulsant activity. Bupropion has been shown to increase blood pressure and pose a risk for exacerbation of unmanaged or pre-existing hypertension, however, clinical trials of bupropion in smokers with CVD have not identified an increased incidence of CV events including stroke or heart attack. In clinical trials, the mean increase in systolic blood pressure associated with the use of bupropion was found to be 1.3 mmHg. •Pharmacodynamics (Drug B): Netilmicin is a semisynthetic, water soluble antibiotic of the aminoglycoside group, produced by the fermentation of Micromonospora inyoensis, a species of actinomycete. Aminoglycosides are useful primarily in infections involving aerobic, Gram-negative bacteria, such as Pseudomonas, Acinetobacter, and Enterobacter. It is active at low concentrations against a wide variety of pathogenic bacteria including Escherichia coli, bacteria of the Klebsiella-Enterobacter-Serratia group, Citrobacter sp., Proteus sp. (indole-positive and indole-negative), including Proteus mirabilis, P. morganii, P. rettgrei, P. vulgaris, Pseudomonas aeruginosa and Neisseria gonorrhoea. Netilmicin is also active in vitro against isolates of Hemophilus influenzae, Salmonella sp., Shigella sp. and against penicillinase and non-penicillinase-producing Staphylococcus including methicillin-resistant strains. Some strains of Providencia sp., Acinetobacter sp. and Aeromonas sp. are also sensitive to netilmicin. Many strains of the above organisms which are found to be resistant to other aminoglycosides, such as kanamycin, gentamicin, tobramycin and sisomicin, are susceptible to netilmicin in vitro. Occasionally, strains have been identified which are resistant to amikacin but susceptible to netilmicin. The combination of netilmicin and penicillin G has a synergistic bactericidal effect against most strains of Streptococcus faecalis (enterococcus). The combined effect of netilmicin and carbenicillin or ticarcillin is synergistic for many strains of Pseudomonas aeruginosa. In addition, many isolates of Serratia, which are resistant to multiple antibiotics, are inhibited by synergistic combinations of netilmicin with carbenicillin, azlocillin, mezlocillin, cefamandole, cefotaxime or moxalactam. Aminoglycosides are mostly ineffective against anaerobic bacteria, fungi and viruses. •Mechanism of action (Drug A): Bupropion is a norepinephrine/dopamine-reuptake inhibitor (NDRI) that exerts its pharmacological effects by weakly inhibiting the enzymes involved in the uptake of the neurotransmitters norepinephrine and dopamine from the synaptic cleft, therefore prolonging their duration of action within the neuronal synapse and the downstream effects of these neurotransmitters. More specifically, bupropion binds to the norepinephrine transporter (NET) and the dopamine transporter (DAT). Bupropion was originally classified as an "atypical" antidepressant because it does not exert the same effects as the classical antidepressants such as Monoamine Oxidase Inhibitors (MAOIs), Tricyclic Antidepressants (TCAs), or Selective Serotonin Reuptake Inhibitors (SSRIs). While it has comparable effectiveness to typical first-line options for the treatment of depression such as SSRIs, bupropion is a unique option for the treatment of MDD as it lacks any clinically relevant serotonergic effects, typical of other mood medications, or any effects on histamine or adrenaline receptors. Lack of activity at these receptors results in a more tolerable side effect profile; bupropion is less likely to cause sexual side effects, sedation, or weight gain as compared to SSRIs or TCAs, for example. When used as an aid to smoking cessation, bupropion is thought to confer its anti-craving and anti-withdrawal effects by inhibiting dopamine reuptake, which is thought to be involved in the reward pathways associated with nicotine, and through the antagonism of the nicotinic acetylcholinergic receptor (AChR), thereby blunting the effects of nicotine. Furthermore, the stimulatory effects produced by bupropion in the central nervous system are similar to nicotine's effects, making low doses of bupropion a suitable option as a nicotine substitute. When used in combination with naltrexone in the marketed product ContraveⓇ for chronic weight management, the two components are thought to have effects on areas of the brain involved in the regulation of food intake. This includes the hypothalamus, which is involved in appetite regulation, and the mesolimbic dopamine circuit, which is involved in reward pathways. Studies have shown that the combined activity of bupropion and naltrexone increase the firing rate of hypothalamic pro-opiomelanocortin (POMC) neurons and blockade of opioid receptor-mediated POMC auto-inhibition, which are associated with a reduction in food intake and increased energy expenditure. This combination was also found to reduce food intake when injected directly into the ventral tegmental area of the mesolimbic circuit in mice, which is an area associated with the regulation of reward pathways. •Mechanism of action (Drug B): Aminoglycosides like netilmicin "irreversibly" bind to specific 30S-subunit proteins and 16S rRNA. Specifically netilmicin binds to four nucleotides of 16S rRNA and a single amino acid of protein S12. This interferes with decoding site in the vicinity of nucleotide 1400 in 16S rRNA of 30S subunit. This region interacts with the wobble base in the anticodon of tRNA. This leads to interference with the initiation complex, misreading of mRNA so incorrect amino acids are inserted into the polypeptide leading to nonfunctional or toxic peptides and the breakup of polysomes into nonfunctional monosomes, leaving the bacterium unable to synthesize proteins vital to its growth. •Absorption (Drug A): Bupropion is currently available in 3 distinct, but bioequivalent formulations: immediate release (IR), sustained-release (SR), and extended-release (XL). Immediate Release Formulation In humans, following oral administration of bupropion hydrochloride tablets, peak plasma bupropion concentrations are usually achieved within 2 hours. IR formulations provide a short duration of action and are therefore generally dosed three times per day. Sustained Release Formulation In humans, following oral administration of bupropion hydrochloride sustained-release tablets (SR), peak plasma concentration (Cmax) of bupropion is usually achieved within 3 hours. SR formulations provide a 12-hour extended release of medication and are therefore generally dosed twice per day. Extended Release Formulation Following single oral administration of bupropion hydrochloride extended-release tablets (XL) to healthy volunteers, the median time to peak plasma concentrations for bupropion was approximately 5 hours. The presence of food did not affect the peak concentration or area under the curve of bupropion. XL formulations provide a 24-hour extended release of medication and are therefore generally dosed once per day/ In a trial comparing chronic dosing with bupropion hydrochloride extended-release tablets (SR) 150 mg twice daily to bupropion immediate-release formulation 100 mg 3 times daily, the steady state Cmax for bupropion after bupropion hydrochloride sustained-release tablets (SR) administration was approximately 85% of those achieved after bupropion immediate-release formulation administration. Exposure (AUC) to bupropion was equivalent for both formulations. Bioequivalence was also demonstrated for all three major active metabolites (i.e., hydroxybupropion, threohydrobupropion and erythrohydrobupropion) for both Cmax and AUC. Thus, at steady state, bupropion hydrochloride sustained-release tablets (SR) given twice daily, and the immediate-release formulation of bupropion given 3 times daily, are essentially bioequivalent for both bupropion and the 3 quantitatively important metabolites. Furthermore, in a study comparing 14-day dosing with bupropion hydrochloride extended-release tablets (XL), 300 mg once-daily to the immediate-release formulation of bupropion at 100 mg 3 times daily, equivalence was demonstrated for peak plasma concentration and area under the curve for bupropion and the three metabolites (hydroxybupropion, threohydrobupropion, and erythrohydrobupropion). Additionally, in a study comparing 14-day dosing with bupropion hydrochloride extended-release tablets (XL) 300 mg once daily to the sustained-release formulation of bupropion at 150 mg 2 times daily, equivalence was demonstrated for peak plasma concentration and area under the curve for bupropion and the three metabolites. Bupropion hydrochloride extended-release tablets (SR) can be taken with or without food. Bupropion Cmax and AUC were increased by 11% to 35% and 16% to 19%, respectively, when bupropion hydrochloride extended-release tablets (SR) was administered with food to healthy volunteers in three trials. The food effect is not considered clinically significant. Following a single-dose administration of bupropion hydrochloride extended-release tablets (SR) in humans, Cmax of bupropion's metabolite hydroxybupropion occurs approximately 6 hours post-dose and is approximately 10 times the peak level of the parent drug at steady state. The elimination half-life of hydroxybupropion is approximately 20 (±5) hours and its AUC at steady state is about 17 times that of bupropion. The times to peak concentrations for the erythrohydrobupropion and threohydrobupropion metabolites are similar to that of the hydroxybupropion metabolite. However, their elimination half-lives are longer, 33(±10) and 37 (±13) hours, respectively, and steady-state AUCs are 1.5 and 7 times that of bupropion, respectively. •Absorption (Drug B): Rapidly and completely absorbed after IM administration, peak serum levels were achieved within 30-60 minutes. Aminoglycosides are poorly absorbed orally. Topical absorption is also poor unless severe skin damage is present. •Volume of distribution (Drug A): No volume of distribution available •Volume of distribution (Drug B): No volume of distribution available •Protein binding (Drug A): In vitro tests show that bupropion is 84% bound to human plasma proteins at concentrations up to 200 mcg per mL. The extent of protein binding of the hydroxybupropion metabolite is similar to that for bupropion, whereas the extent of protein binding of the threohydrobupropion metabolite is about half that seen with bupropion. •Protein binding (Drug B): Protein-binding of is low and depends on the test conditions (mainly the concentration of cations in the test medium). •Metabolism (Drug A): Bupropion is extensively metabolized in humans. Three metabolites are active: hydroxybupropion, which is formed via hydroxylation of the tert-butyl group of bupropion, and the amino-alcohol isomers, threohydrobupropion and erythrohydrobupropion, which are formed via reduction of the carbonyl group. In vitro findings suggest that CYP2B6 is the principal isoenzyme involved in the formation of hydroxybupropion, while cytochrome P450 enzymes are not involved in the formation of threohydrobupropion. Hydroxybupropion has been shown to have the same affinity as bupropion for the norepinephrine transporter (NET) but approximately 50% of its antidepressant activity despite reaching concentrations of ~10-fold higher than that of the parent drug. Oxidation of the bupropion side chain results in the formation of a glycine conjugate of meta-chlorobenzoic acid, which is then excreted as the major urinary metabolite. The potency and toxicity of the metabolites relative to bupropion have not been fully characterized. However, it has been demonstrated in an antidepressant screening test in mice that hydroxybupropion is one-half as potent as bupropion, while threohydrobupropion and erythrohydrobupropion are 5-fold less potent than bupropion. This may be of clinical importance because the plasma concentrations of the metabolites are as high as or higher than those of bupropion. Bupropion and its metabolites exhibit linear kinetics following chronic administration of 300 to 450 mg per day. •Metabolism (Drug B): No evidence of metabolic transformation, typically 80% is recoverable in the urine within 24 hours •Route of elimination (Drug A): Bupropion is extensively metabolized in humans. Oxidation of the bupropion side chain results in the formation of a glycine conjugate of metachlorobenzoic acid, which is then excreted as the major urinary metabolite. Following oral administration of 200 mg of 14C-bupropion in humans, 87% and 10% of the radioactive dose were recovered in the urine and feces, respectively. However, the fraction of the oral dose of bupropion excreted unchanged was only 0.5%, a finding consistent with the extensive metabolism of bupropion. •Route of elimination (Drug B): No route of elimination available •Half-life (Drug A): 24 hours •Half-life (Drug B): 2.5 hours •Clearance (Drug A): No clearance available •Clearance (Drug B): No clearance available •Toxicity (Drug A): Symptoms of overdose include seizures, hallucinations, loss of consciousness, tachycardia, and cardiac arrest. •Toxicity (Drug B): Netilmicin has nephrotoxic and ototoxic potential. Nephrotoxicity occurs via drug accumulation in renal proximal tubular cells resulting in cellular damage. Tubular cells may regenerate despite continued exposure and nephrotoxicity is usually mild and reversible. Netilmicin is less nephrotoxic than neomycin, gentamicin, tobramycin, and amikacin, likely due to a reduced number of cationic amino groups in its structure. Otoxicity occurs as a result of irreversible damage to hair cells of the cochlea and/or summit of the ampullar cristae in the vestibular complex caused drug accumulation in the endolymph and perilymph of the inner ear. Otoxicity appears to be correlated to total exposure and may be cumulative with further doses of aminoglycosides or other ototoxic drugs (e.g. cisplatin, furosemide). High frequency hearing loss is followed by low frequency hearing loss, which may be followed by retrograde degeneration of the auditory nerve. Vestibular toxicity may cause vertigo, nausea and vomiting, dizziness and loss of balance. •Brand Names (Drug A): Aplenzin, Auvelity, Budeprion, Contrave, Forfivo, Wellbutrin, Zyban •Brand Names (Drug B): No brand names available •Synonyms (Drug A): No synonyms listed •Synonyms (Drug B): No synonyms listed •Summary (Drug A): Bupropion is a norepinephrine and dopamine reuptake inhibitor used in the treatment of major depressive disorder (MDD), seasonal affective disorder (SAD), and as an aid to smoking cessation. •Summary (Drug B): Netilmicin is an aminoglycoside used to treat a wide variety of infections in the body. Output: The renal excretion of drugs is the overall result of a combination of kidney processes that include glomerular filtration, passive diffusion, tubular secretion, and tubular reabsorption. Since two of these mechanisms - tubular secretion and reabsorption - are saturable processes , they are consequently susceptible to competition between multiple substrates excreted by the kidneys. If two or more medications that are mainly renally excreted are co-administered, they may compete for renal elimination; there is a large likelihood that one agent may "out-compete" or saturate the renal excretion mechanisms before the other concomitantly administered agent(s) are excreted. As a result, the elimination of these other concurrently administered agents may be inhibited or otherwise delayed, which could lead to increases in their serum concentrations and the risk, incidence, and/or severity of adverse effects associated with the exposure to such drugs. The affected drug is a narrow therapeutic index drug that undergoes renal excretion as its main elimination pathway: a change in serum concentration may significantly elevate the risk of developing drug-related adverse effects. The severity of the interaction is moderate.

Does Bupropion and Nevirapine interact?

•Drug A: Bupropion •Drug B: Nevirapine •Severity: MAJOR •Description: The metabolism of Nevirapine can be decreased when combined with Bupropion. •Extended Description: The subject drug is a strong CYP2D6 inhibitor and the affected drug is metabolized by CYP2D6. Concomitant administration may decrease the metabolism of the affected drug, which could increase serum concentrations as well as the risk and severity of adverse effects. •Indication (Drug A): Bupropion is indicated for the treatment of major depressive disorder (MDD), seasonal affective disorder (SAD), and as an aid to smoking cessation. When used in combination with naltrexone as the marketed product ContraveⓇ, bupropion is indicated as an adjunct to a reduced-calorie diet and increased physical activity for chronic weight management in adults with an initial body mass index (BMI) of: 30 kg/m^2 or greater (obese) or 27 kg/m^2 or greater (overweight) in the presence of at least one weight-related comorbid condition (e.g., hypertension, type 2 diabetes mellitus, or dyslipidemia). Bupropion is also used off-label as a first-line treatment in patients with ADHD and comorbid bipolar disorder when used as an adjunct to mood stabilizers. •Indication (Drug B): For use in combination with other antiretroviral drugs in the ongoing treatment of HIV-1 infection. •Pharmacodynamics (Drug A): Bupropion is chemically unrelated to tricyclic, tetracyclic, selective serotonin re-uptake inhibitors, or other known antidepressant agents. Compared to classical tricyclic antidepressants, Bupropion is a relatively weak inhibitor of the neuronal uptake of norepinephrine and dopamine. In addition, Bupropion does not inhibit monoamine oxidase. Bupropion has been found to be essentially inactive at the serotonin transporter (SERT)(IC50 >10 000 nM), however both bupropion and its primary metabolite hydroxybupropion have been found to block the function of cation-selective serotonin type 3A receptors (5-HT3ARs). Bupropion produces dose-related central nervous system (CNS) stimulant effects in animals, as evidenced by increased locomotor activity, increased rates of responding in various schedule-controlled operant behaviour tasks, and, at high doses, induction of mild stereotyped behaviour. Due to these stimulant effects and selective activity at dopamine and norepinephrine receptors, bupropion has been identified as having an abuse potential. Bupropion has a similar structure to the controlled substance Cathinone, and has been identified as having mild amphetamine-like activity, particularly when inhaled or injected. Bupropion is also known to lower the seizure threshold, making any pre-existing seizure conditions a contraindication to its use. This risk is exacerbated when bupropion is combined with other drugs or substances that lower the seizure threshold, such as cocaine, or in clinical situations that would increase the risk of a seizure such as abrupt alcohol or benzodiazepine withdrawal. As norepinephrine has been shown to have anticonvulsant properties, bupropion's inhibitory effects on NET are thought to contribute to its pro-convulsant activity. Bupropion has been shown to increase blood pressure and pose a risk for exacerbation of unmanaged or pre-existing hypertension, however, clinical trials of bupropion in smokers with CVD have not identified an increased incidence of CV events including stroke or heart attack. In clinical trials, the mean increase in systolic blood pressure associated with the use of bupropion was found to be 1.3 mmHg. •Pharmacodynamics (Drug B): Nevirapine is a non-nucleoside reverse transcriptase inhibitor (nNRTI) with activity against Human Immunodeficiency Virus Type 1 (HIV-1). HIV-2 RT and eukaryotic DNA polymerases (such as human DNA polymerases alpha, beta, or sigma) are not inhibited by nevirapine. Nevirapine is, in general, only prescribed after the immune system has declined and infections have become evident. It is always taken with at least one other HIV medication such as Retrovir or Videx. The virus can develop resistance to nevirapine if the drug is taken alone, although even if used properly, nevirapine is effective for only a limited time. •Mechanism of action (Drug A): Bupropion is a norepinephrine/dopamine-reuptake inhibitor (NDRI) that exerts its pharmacological effects by weakly inhibiting the enzymes involved in the uptake of the neurotransmitters norepinephrine and dopamine from the synaptic cleft, therefore prolonging their duration of action within the neuronal synapse and the downstream effects of these neurotransmitters. More specifically, bupropion binds to the norepinephrine transporter (NET) and the dopamine transporter (DAT). Bupropion was originally classified as an "atypical" antidepressant because it does not exert the same effects as the classical antidepressants such as Monoamine Oxidase Inhibitors (MAOIs), Tricyclic Antidepressants (TCAs), or Selective Serotonin Reuptake Inhibitors (SSRIs). While it has comparable effectiveness to typical first-line options for the treatment of depression such as SSRIs, bupropion is a unique option for the treatment of MDD as it lacks any clinically relevant serotonergic effects, typical of other mood medications, or any effects on histamine or adrenaline receptors. Lack of activity at these receptors results in a more tolerable side effect profile; bupropion is less likely to cause sexual side effects, sedation, or weight gain as compared to SSRIs or TCAs, for example. When used as an aid to smoking cessation, bupropion is thought to confer its anti-craving and anti-withdrawal effects by inhibiting dopamine reuptake, which is thought to be involved in the reward pathways associated with nicotine, and through the antagonism of the nicotinic acetylcholinergic receptor (AChR), thereby blunting the effects of nicotine. Furthermore, the stimulatory effects produced by bupropion in the central nervous system are similar to nicotine's effects, making low doses of bupropion a suitable option as a nicotine substitute. When used in combination with naltrexone in the marketed product ContraveⓇ for chronic weight management, the two components are thought to have effects on areas of the brain involved in the regulation of food intake. This includes the hypothalamus, which is involved in appetite regulation, and the mesolimbic dopamine circuit, which is involved in reward pathways. Studies have shown that the combined activity of bupropion and naltrexone increase the firing rate of hypothalamic pro-opiomelanocortin (POMC) neurons and blockade of opioid receptor-mediated POMC auto-inhibition, which are associated with a reduction in food intake and increased energy expenditure. This combination was also found to reduce food intake when injected directly into the ventral tegmental area of the mesolimbic circuit in mice, which is an area associated with the regulation of reward pathways. •Mechanism of action (Drug B): Nevirapine binds directly to reverse transcriptase (RT) and blocks the RNA-dependent and DNA-dependent DNA polymerase activities by causing a disruption of the enzyme's catalytic site. The activity of nevirapine does not compete with template or nucleoside triphosphates. •Absorption (Drug A): Bupropion is currently available in 3 distinct, but bioequivalent formulations: immediate release (IR), sustained-release (SR), and extended-release (XL). Immediate Release Formulation In humans, following oral administration of bupropion hydrochloride tablets, peak plasma bupropion concentrations are usually achieved within 2 hours. IR formulations provide a short duration of action and are therefore generally dosed three times per day. Sustained Release Formulation In humans, following oral administration of bupropion hydrochloride sustained-release tablets (SR), peak plasma concentration (Cmax) of bupropion is usually achieved within 3 hours. SR formulations provide a 12-hour extended release of medication and are therefore generally dosed twice per day. Extended Release Formulation Following single oral administration of bupropion hydrochloride extended-release tablets (XL) to healthy volunteers, the median time to peak plasma concentrations for bupropion was approximately 5 hours. The presence of food did not affect the peak concentration or area under the curve of bupropion. XL formulations provide a 24-hour extended release of medication and are therefore generally dosed once per day/ In a trial comparing chronic dosing with bupropion hydrochloride extended-release tablets (SR) 150 mg twice daily to bupropion immediate-release formulation 100 mg 3 times daily, the steady state Cmax for bupropion after bupropion hydrochloride sustained-release tablets (SR) administration was approximately 85% of those achieved after bupropion immediate-release formulation administration. Exposure (AUC) to bupropion was equivalent for both formulations. Bioequivalence was also demonstrated for all three major active metabolites (i.e., hydroxybupropion, threohydrobupropion and erythrohydrobupropion) for both Cmax and AUC. Thus, at steady state, bupropion hydrochloride sustained-release tablets (SR) given twice daily, and the immediate-release formulation of bupropion given 3 times daily, are essentially bioequivalent for both bupropion and the 3 quantitatively important metabolites. Furthermore, in a study comparing 14-day dosing with bupropion hydrochloride extended-release tablets (XL), 300 mg once-daily to the immediate-release formulation of bupropion at 100 mg 3 times daily, equivalence was demonstrated for peak plasma concentration and area under the curve for bupropion and the three metabolites (hydroxybupropion, threohydrobupropion, and erythrohydrobupropion). Additionally, in a study comparing 14-day dosing with bupropion hydrochloride extended-release tablets (XL) 300 mg once daily to the sustained-release formulation of bupropion at 150 mg 2 times daily, equivalence was demonstrated for peak plasma concentration and area under the curve for bupropion and the three metabolites. Bupropion hydrochloride extended-release tablets (SR) can be taken with or without food. Bupropion Cmax and AUC were increased by 11% to 35% and 16% to 19%, respectively, when bupropion hydrochloride extended-release tablets (SR) was administered with food to healthy volunteers in three trials. The food effect is not considered clinically significant. Following a single-dose administration of bupropion hydrochloride extended-release tablets (SR) in humans, Cmax of bupropion's metabolite hydroxybupropion occurs approximately 6 hours post-dose and is approximately 10 times the peak level of the parent drug at steady state. The elimination half-life of hydroxybupropion is approximately 20 (±5) hours and its AUC at steady state is about 17 times that of bupropion. The times to peak concentrations for the erythrohydrobupropion and threohydrobupropion metabolites are similar to that of the hydroxybupropion metabolite. However, their elimination half-lives are longer, 33(±10) and 37 (±13) hours, respectively, and steady-state AUCs are 1.5 and 7 times that of bupropion, respectively. •Absorption (Drug B): Nevirapine is readily absorbed (greater than 90%) after oral administration in healthy subjects and adults with HIV-1 infection. The absolute bioavailability in healthy adults following a single dose administration is 93 ± 9% (mean ± SD) for a 50 mg tablet and 91 ± 8% for an oral solution. Peak plasma nevirapine concentrations of 2 ± 0.4 mcg/mL (7.5 micromolar) were attained by 4 hours following a single 200 mg dose. Nevirapine tablets and suspension have been shown to be comparably bioavailable and interchangeable at doses up to 200 mg. When the oral tablet is given with a high-fat meal, the extent of absorption is compared to that of the fasted-state. •Volume of distribution (Drug A): No volume of distribution available •Volume of distribution (Drug B): 1.21 ± 0.09 L/kg [apparent volume of distribution, healthy adults, IV] Nevirapine is capable of crossing the placenta and is found in breast milk. •Protein binding (Drug A): In vitro tests show that bupropion is 84% bound to human plasma proteins at concentrations up to 200 mcg per mL. The extent of protein binding of the hydroxybupropion metabolite is similar to that for bupropion, whereas the extent of protein binding of the threohydrobupropion metabolite is about half that seen with bupropion. •Protein binding (Drug B): 60% bound to plasma protein. •Metabolism (Drug A): Bupropion is extensively metabolized in humans. Three metabolites are active: hydroxybupropion, which is formed via hydroxylation of the tert-butyl group of bupropion, and the amino-alcohol isomers, threohydrobupropion and erythrohydrobupropion, which are formed via reduction of the carbonyl group. In vitro findings suggest that CYP2B6 is the principal isoenzyme involved in the formation of hydroxybupropion, while cytochrome P450 enzymes are not involved in the formation of threohydrobupropion. Hydroxybupropion has been shown to have the same affinity as bupropion for the norepinephrine transporter (NET) but approximately 50% of its antidepressant activity despite reaching concentrations of ~10-fold higher than that of the parent drug. Oxidation of the bupropion side chain results in the formation of a glycine conjugate of meta-chlorobenzoic acid, which is then excreted as the major urinary metabolite. The potency and toxicity of the metabolites relative to bupropion have not been fully characterized. However, it has been demonstrated in an antidepressant screening test in mice that hydroxybupropion is one-half as potent as bupropion, while threohydrobupropion and erythrohydrobupropion are 5-fold less potent than bupropion. This may be of clinical importance because the plasma concentrations of the metabolites are as high as or higher than those of bupropion. Bupropion and its metabolites exhibit linear kinetics following chronic administration of 300 to 450 mg per day. •Metabolism (Drug B): Hepatic. In vivo studies in humans and in vitro studies with human liver microsomes have shown that nevirapine is extensively biotransformed via cytochrome P450 3A4 metabolism to several hydroxylated metabolites. •Route of elimination (Drug A): Bupropion is extensively metabolized in humans. Oxidation of the bupropion side chain results in the formation of a glycine conjugate of metachlorobenzoic acid, which is then excreted as the major urinary metabolite. Following oral administration of 200 mg of 14C-bupropion in humans, 87% and 10% of the radioactive dose were recovered in the urine and feces, respectively. However, the fraction of the oral dose of bupropion excreted unchanged was only 0.5%, a finding consistent with the extensive metabolism of bupropion. •Route of elimination (Drug B): Thus cytochrome P450 metabolism, glucuronide conjugation, and urinary excretion of glucuronidated metabolites represent the primary route of nevirapine biotransformation and elimination in humans. Only a small fraction (<5%) of the radioactivity in urine (representing <3% of the total dose) was made up of parent compound; therefore, renal excretion plays a minor role in elimination of the parent compound. •Half-life (Drug A): 24 hours •Half-life (Drug B): 45 hours •Clearance (Drug A): No clearance available •Clearance (Drug B): No clearance available •Toxicity (Drug A): Symptoms of overdose include seizures, hallucinations, loss of consciousness, tachycardia, and cardiac arrest. •Toxicity (Drug B): Symptoms of overdose include edema, erythema nodosum, fatigue, fever, headache, insomnia, nausea, pulmonaryinfiltrates, rash, vertigo, vomiting, and weight decrease. The most common adverse reaction is rash. •Brand Names (Drug A): Aplenzin, Auvelity, Budeprion, Contrave, Forfivo, Wellbutrin, Zyban •Brand Names (Drug B): Viramune •Synonyms (Drug A): No synonyms listed •Synonyms (Drug B): Nevirapina Nevirapine •Summary (Drug A): Bupropion is a norepinephrine and dopamine reuptake inhibitor used in the treatment of major depressive disorder (MDD), seasonal affective disorder (SAD), and as an aid to smoking cessation. •Summary (Drug B): Nevirapine is a non-nucleoside reverse transcriptase inhibitor used as part of a management regimen for HIV-1 virus infection.

The subject drug is a strong CYP2D6 inhibitor and the affected drug is metabolized by CYP2D6. Concomitant administration may decrease the metabolism of the affected drug, which could increase serum concentrations as well as the risk and severity of adverse effects. The severity of the interaction is major.

Question: Does Bupropion and Nevirapine interact? Information: •Drug A: Bupropion •Drug B: Nevirapine •Severity: MAJOR •Description: The metabolism of Nevirapine can be decreased when combined with Bupropion. •Extended Description: The subject drug is a strong CYP2D6 inhibitor and the affected drug is metabolized by CYP2D6. Concomitant administration may decrease the metabolism of the affected drug, which could increase serum concentrations as well as the risk and severity of adverse effects. •Indication (Drug A): Bupropion is indicated for the treatment of major depressive disorder (MDD), seasonal affective disorder (SAD), and as an aid to smoking cessation. When used in combination with naltrexone as the marketed product ContraveⓇ, bupropion is indicated as an adjunct to a reduced-calorie diet and increased physical activity for chronic weight management in adults with an initial body mass index (BMI) of: 30 kg/m^2 or greater (obese) or 27 kg/m^2 or greater (overweight) in the presence of at least one weight-related comorbid condition (e.g., hypertension, type 2 diabetes mellitus, or dyslipidemia). Bupropion is also used off-label as a first-line treatment in patients with ADHD and comorbid bipolar disorder when used as an adjunct to mood stabilizers. •Indication (Drug B): For use in combination with other antiretroviral drugs in the ongoing treatment of HIV-1 infection. •Pharmacodynamics (Drug A): Bupropion is chemically unrelated to tricyclic, tetracyclic, selective serotonin re-uptake inhibitors, or other known antidepressant agents. Compared to classical tricyclic antidepressants, Bupropion is a relatively weak inhibitor of the neuronal uptake of norepinephrine and dopamine. In addition, Bupropion does not inhibit monoamine oxidase. Bupropion has been found to be essentially inactive at the serotonin transporter (SERT)(IC50 >10 000 nM), however both bupropion and its primary metabolite hydroxybupropion have been found to block the function of cation-selective serotonin type 3A receptors (5-HT3ARs). Bupropion produces dose-related central nervous system (CNS) stimulant effects in animals, as evidenced by increased locomotor activity, increased rates of responding in various schedule-controlled operant behaviour tasks, and, at high doses, induction of mild stereotyped behaviour. Due to these stimulant effects and selective activity at dopamine and norepinephrine receptors, bupropion has been identified as having an abuse potential. Bupropion has a similar structure to the controlled substance Cathinone, and has been identified as having mild amphetamine-like activity, particularly when inhaled or injected. Bupropion is also known to lower the seizure threshold, making any pre-existing seizure conditions a contraindication to its use. This risk is exacerbated when bupropion is combined with other drugs or substances that lower the seizure threshold, such as cocaine, or in clinical situations that would increase the risk of a seizure such as abrupt alcohol or benzodiazepine withdrawal. As norepinephrine has been shown to have anticonvulsant properties, bupropion's inhibitory effects on NET are thought to contribute to its pro-convulsant activity. Bupropion has been shown to increase blood pressure and pose a risk for exacerbation of unmanaged or pre-existing hypertension, however, clinical trials of bupropion in smokers with CVD have not identified an increased incidence of CV events including stroke or heart attack. In clinical trials, the mean increase in systolic blood pressure associated with the use of bupropion was found to be 1.3 mmHg. •Pharmacodynamics (Drug B): Nevirapine is a non-nucleoside reverse transcriptase inhibitor (nNRTI) with activity against Human Immunodeficiency Virus Type 1 (HIV-1). HIV-2 RT and eukaryotic DNA polymerases (such as human DNA polymerases alpha, beta, or sigma) are not inhibited by nevirapine. Nevirapine is, in general, only prescribed after the immune system has declined and infections have become evident. It is always taken with at least one other HIV medication such as Retrovir or Videx. The virus can develop resistance to nevirapine if the drug is taken alone, although even if used properly, nevirapine is effective for only a limited time. •Mechanism of action (Drug A): Bupropion is a norepinephrine/dopamine-reuptake inhibitor (NDRI) that exerts its pharmacological effects by weakly inhibiting the enzymes involved in the uptake of the neurotransmitters norepinephrine and dopamine from the synaptic cleft, therefore prolonging their duration of action within the neuronal synapse and the downstream effects of these neurotransmitters. More specifically, bupropion binds to the norepinephrine transporter (NET) and the dopamine transporter (DAT). Bupropion was originally classified as an "atypical" antidepressant because it does not exert the same effects as the classical antidepressants such as Monoamine Oxidase Inhibitors (MAOIs), Tricyclic Antidepressants (TCAs), or Selective Serotonin Reuptake Inhibitors (SSRIs). While it has comparable effectiveness to typical first-line options for the treatment of depression such as SSRIs, bupropion is a unique option for the treatment of MDD as it lacks any clinically relevant serotonergic effects, typical of other mood medications, or any effects on histamine or adrenaline receptors. Lack of activity at these receptors results in a more tolerable side effect profile; bupropion is less likely to cause sexual side effects, sedation, or weight gain as compared to SSRIs or TCAs, for example. When used as an aid to smoking cessation, bupropion is thought to confer its anti-craving and anti-withdrawal effects by inhibiting dopamine reuptake, which is thought to be involved in the reward pathways associated with nicotine, and through the antagonism of the nicotinic acetylcholinergic receptor (AChR), thereby blunting the effects of nicotine. Furthermore, the stimulatory effects produced by bupropion in the central nervous system are similar to nicotine's effects, making low doses of bupropion a suitable option as a nicotine substitute. When used in combination with naltrexone in the marketed product ContraveⓇ for chronic weight management, the two components are thought to have effects on areas of the brain involved in the regulation of food intake. This includes the hypothalamus, which is involved in appetite regulation, and the mesolimbic dopamine circuit, which is involved in reward pathways. Studies have shown that the combined activity of bupropion and naltrexone increase the firing rate of hypothalamic pro-opiomelanocortin (POMC) neurons and blockade of opioid receptor-mediated POMC auto-inhibition, which are associated with a reduction in food intake and increased energy expenditure. This combination was also found to reduce food intake when injected directly into the ventral tegmental area of the mesolimbic circuit in mice, which is an area associated with the regulation of reward pathways. •Mechanism of action (Drug B): Nevirapine binds directly to reverse transcriptase (RT) and blocks the RNA-dependent and DNA-dependent DNA polymerase activities by causing a disruption of the enzyme's catalytic site. The activity of nevirapine does not compete with template or nucleoside triphosphates. •Absorption (Drug A): Bupropion is currently available in 3 distinct, but bioequivalent formulations: immediate release (IR), sustained-release (SR), and extended-release (XL). Immediate Release Formulation In humans, following oral administration of bupropion hydrochloride tablets, peak plasma bupropion concentrations are usually achieved within 2 hours. IR formulations provide a short duration of action and are therefore generally dosed three times per day. Sustained Release Formulation In humans, following oral administration of bupropion hydrochloride sustained-release tablets (SR), peak plasma concentration (Cmax) of bupropion is usually achieved within 3 hours. SR formulations provide a 12-hour extended release of medication and are therefore generally dosed twice per day. Extended Release Formulation Following single oral administration of bupropion hydrochloride extended-release tablets (XL) to healthy volunteers, the median time to peak plasma concentrations for bupropion was approximately 5 hours. The presence of food did not affect the peak concentration or area under the curve of bupropion. XL formulations provide a 24-hour extended release of medication and are therefore generally dosed once per day/ In a trial comparing chronic dosing with bupropion hydrochloride extended-release tablets (SR) 150 mg twice daily to bupropion immediate-release formulation 100 mg 3 times daily, the steady state Cmax for bupropion after bupropion hydrochloride sustained-release tablets (SR) administration was approximately 85% of those achieved after bupropion immediate-release formulation administration. Exposure (AUC) to bupropion was equivalent for both formulations. Bioequivalence was also demonstrated for all three major active metabolites (i.e., hydroxybupropion, threohydrobupropion and erythrohydrobupropion) for both Cmax and AUC. Thus, at steady state, bupropion hydrochloride sustained-release tablets (SR) given twice daily, and the immediate-release formulation of bupropion given 3 times daily, are essentially bioequivalent for both bupropion and the 3 quantitatively important metabolites. Furthermore, in a study comparing 14-day dosing with bupropion hydrochloride extended-release tablets (XL), 300 mg once-daily to the immediate-release formulation of bupropion at 100 mg 3 times daily, equivalence was demonstrated for peak plasma concentration and area under the curve for bupropion and the three metabolites (hydroxybupropion, threohydrobupropion, and erythrohydrobupropion). Additionally, in a study comparing 14-day dosing with bupropion hydrochloride extended-release tablets (XL) 300 mg once daily to the sustained-release formulation of bupropion at 150 mg 2 times daily, equivalence was demonstrated for peak plasma concentration and area under the curve for bupropion and the three metabolites. Bupropion hydrochloride extended-release tablets (SR) can be taken with or without food. Bupropion Cmax and AUC were increased by 11% to 35% and 16% to 19%, respectively, when bupropion hydrochloride extended-release tablets (SR) was administered with food to healthy volunteers in three trials. The food effect is not considered clinically significant. Following a single-dose administration of bupropion hydrochloride extended-release tablets (SR) in humans, Cmax of bupropion's metabolite hydroxybupropion occurs approximately 6 hours post-dose and is approximately 10 times the peak level of the parent drug at steady state. The elimination half-life of hydroxybupropion is approximately 20 (±5) hours and its AUC at steady state is about 17 times that of bupropion. The times to peak concentrations for the erythrohydrobupropion and threohydrobupropion metabolites are similar to that of the hydroxybupropion metabolite. However, their elimination half-lives are longer, 33(±10) and 37 (±13) hours, respectively, and steady-state AUCs are 1.5 and 7 times that of bupropion, respectively. •Absorption (Drug B): Nevirapine is readily absorbed (greater than 90%) after oral administration in healthy subjects and adults with HIV-1 infection. The absolute bioavailability in healthy adults following a single dose administration is 93 ± 9% (mean ± SD) for a 50 mg tablet and 91 ± 8% for an oral solution. Peak plasma nevirapine concentrations of 2 ± 0.4 mcg/mL (7.5 micromolar) were attained by 4 hours following a single 200 mg dose. Nevirapine tablets and suspension have been shown to be comparably bioavailable and interchangeable at doses up to 200 mg. When the oral tablet is given with a high-fat meal, the extent of absorption is compared to that of the fasted-state. •Volume of distribution (Drug A): No volume of distribution available •Volume of distribution (Drug B): 1.21 ± 0.09 L/kg [apparent volume of distribution, healthy adults, IV] Nevirapine is capable of crossing the placenta and is found in breast milk. •Protein binding (Drug A): In vitro tests show that bupropion is 84% bound to human plasma proteins at concentrations up to 200 mcg per mL. The extent of protein binding of the hydroxybupropion metabolite is similar to that for bupropion, whereas the extent of protein binding of the threohydrobupropion metabolite is about half that seen with bupropion. •Protein binding (Drug B): 60% bound to plasma protein. •Metabolism (Drug A): Bupropion is extensively metabolized in humans. Three metabolites are active: hydroxybupropion, which is formed via hydroxylation of the tert-butyl group of bupropion, and the amino-alcohol isomers, threohydrobupropion and erythrohydrobupropion, which are formed via reduction of the carbonyl group. In vitro findings suggest that CYP2B6 is the principal isoenzyme involved in the formation of hydroxybupropion, while cytochrome P450 enzymes are not involved in the formation of threohydrobupropion. Hydroxybupropion has been shown to have the same affinity as bupropion for the norepinephrine transporter (NET) but approximately 50% of its antidepressant activity despite reaching concentrations of ~10-fold higher than that of the parent drug. Oxidation of the bupropion side chain results in the formation of a glycine conjugate of meta-chlorobenzoic acid, which is then excreted as the major urinary metabolite. The potency and toxicity of the metabolites relative to bupropion have not been fully characterized. However, it has been demonstrated in an antidepressant screening test in mice that hydroxybupropion is one-half as potent as bupropion, while threohydrobupropion and erythrohydrobupropion are 5-fold less potent than bupropion. This may be of clinical importance because the plasma concentrations of the metabolites are as high as or higher than those of bupropion. Bupropion and its metabolites exhibit linear kinetics following chronic administration of 300 to 450 mg per day. •Metabolism (Drug B): Hepatic. In vivo studies in humans and in vitro studies with human liver microsomes have shown that nevirapine is extensively biotransformed via cytochrome P450 3A4 metabolism to several hydroxylated metabolites. •Route of elimination (Drug A): Bupropion is extensively metabolized in humans. Oxidation of the bupropion side chain results in the formation of a glycine conjugate of metachlorobenzoic acid, which is then excreted as the major urinary metabolite. Following oral administration of 200 mg of 14C-bupropion in humans, 87% and 10% of the radioactive dose were recovered in the urine and feces, respectively. However, the fraction of the oral dose of bupropion excreted unchanged was only 0.5%, a finding consistent with the extensive metabolism of bupropion. •Route of elimination (Drug B): Thus cytochrome P450 metabolism, glucuronide conjugation, and urinary excretion of glucuronidated metabolites represent the primary route of nevirapine biotransformation and elimination in humans. Only a small fraction (<5%) of the radioactivity in urine (representing <3% of the total dose) was made up of parent compound; therefore, renal excretion plays a minor role in elimination of the parent compound. •Half-life (Drug A): 24 hours •Half-life (Drug B): 45 hours •Clearance (Drug A): No clearance available •Clearance (Drug B): No clearance available •Toxicity (Drug A): Symptoms of overdose include seizures, hallucinations, loss of consciousness, tachycardia, and cardiac arrest. •Toxicity (Drug B): Symptoms of overdose include edema, erythema nodosum, fatigue, fever, headache, insomnia, nausea, pulmonaryinfiltrates, rash, vertigo, vomiting, and weight decrease. The most common adverse reaction is rash. •Brand Names (Drug A): Aplenzin, Auvelity, Budeprion, Contrave, Forfivo, Wellbutrin, Zyban •Brand Names (Drug B): Viramune •Synonyms (Drug A): No synonyms listed •Synonyms (Drug B): Nevirapina Nevirapine •Summary (Drug A): Bupropion is a norepinephrine and dopamine reuptake inhibitor used in the treatment of major depressive disorder (MDD), seasonal affective disorder (SAD), and as an aid to smoking cessation. •Summary (Drug B): Nevirapine is a non-nucleoside reverse transcriptase inhibitor used as part of a management regimen for HIV-1 virus infection. Output: The subject drug is a strong CYP2D6 inhibitor and the affected drug is metabolized by CYP2D6. Concomitant administration may decrease the metabolism of the affected drug, which could increase serum concentrations as well as the risk and severity of adverse effects. The severity of the interaction is major.

Does Bupropion and Nicardipine interact?

•Drug A: Bupropion •Drug B: Nicardipine •Severity: MAJOR •Description: The metabolism of Bupropion can be decreased when combined with Nicardipine. •Extended Description: The subject drug is a strong inhibitor of CYP2C9 while the affected drug is metabolized by CYP2C9. Concomitant administration will lead to an increase in serum concentrations of the affected drug, leading to accumulation of the drug and an increase in the risk and severity of adverse effects. •Indication (Drug A): Bupropion is indicated for the treatment of major depressive disorder (MDD), seasonal affective disorder (SAD), and as an aid to smoking cessation. When used in combination with naltrexone as the marketed product ContraveⓇ, bupropion is indicated as an adjunct to a reduced-calorie diet and increased physical activity for chronic weight management in adults with an initial body mass index (BMI) of: 30 kg/m^2 or greater (obese) or 27 kg/m^2 or greater (overweight) in the presence of at least one weight-related comorbid condition (e.g., hypertension, type 2 diabetes mellitus, or dyslipidemia). Bupropion is also used off-label as a first-line treatment in patients with ADHD and comorbid bipolar disorder when used as an adjunct to mood stabilizers. •Indication (Drug B): Used for the management of patients with chronic stable angina and for the treatment of hypertension. •Pharmacodynamics (Drug A): Bupropion is chemically unrelated to tricyclic, tetracyclic, selective serotonin re-uptake inhibitors, or other known antidepressant agents. Compared to classical tricyclic antidepressants, Bupropion is a relatively weak inhibitor of the neuronal uptake of norepinephrine and dopamine. In addition, Bupropion does not inhibit monoamine oxidase. Bupropion has been found to be essentially inactive at the serotonin transporter (SERT)(IC50 >10 000 nM), however both bupropion and its primary metabolite hydroxybupropion have been found to block the function of cation-selective serotonin type 3A receptors (5-HT3ARs). Bupropion produces dose-related central nervous system (CNS) stimulant effects in animals, as evidenced by increased locomotor activity, increased rates of responding in various schedule-controlled operant behaviour tasks, and, at high doses, induction of mild stereotyped behaviour. Due to these stimulant effects and selective activity at dopamine and norepinephrine receptors, bupropion has been identified as having an abuse potential. Bupropion has a similar structure to the controlled substance Cathinone, and has been identified as having mild amphetamine-like activity, particularly when inhaled or injected. Bupropion is also known to lower the seizure threshold, making any pre-existing seizure conditions a contraindication to its use. This risk is exacerbated when bupropion is combined with other drugs or substances that lower the seizure threshold, such as cocaine, or in clinical situations that would increase the risk of a seizure such as abrupt alcohol or benzodiazepine withdrawal. As norepinephrine has been shown to have anticonvulsant properties, bupropion's inhibitory effects on NET are thought to contribute to its pro-convulsant activity. Bupropion has been shown to increase blood pressure and pose a risk for exacerbation of unmanaged or pre-existing hypertension, however, clinical trials of bupropion in smokers with CVD have not identified an increased incidence of CV events including stroke or heart attack. In clinical trials, the mean increase in systolic blood pressure associated with the use of bupropion was found to be 1.3 mmHg. •Pharmacodynamics (Drug B): Nicardipine, a dihydropyridine calcium-channel blocker, is used alone or with an angiotensin-converting enzyme inhibitor, to treat hypertension, chronic stable angina pectoris, and Prinzmetal's variant angina. Nicardipine is similar to other peripheral vasodilators. Nicardipine inhibits the influx of extra cellular calcium across the myocardial and vascular smooth muscle cell membranes possibly by deforming the channel, inhibiting ion-control gating mechanisms, and/or interfering with the release of calcium from the sarcoplasmic reticulum. The decrease in intracellular calcium inhibits the contractile processes of the myocardial smooth muscle cells, causing dilation of the coronary and systemic arteries, increased oxygen delivery to the myocardial tissue, decreased total peripheral resistance, decreased systemic blood pressure, and decreased afterload. •Mechanism of action (Drug A): Bupropion is a norepinephrine/dopamine-reuptake inhibitor (NDRI) that exerts its pharmacological effects by weakly inhibiting the enzymes involved in the uptake of the neurotransmitters norepinephrine and dopamine from the synaptic cleft, therefore prolonging their duration of action within the neuronal synapse and the downstream effects of these neurotransmitters. More specifically, bupropion binds to the norepinephrine transporter (NET) and the dopamine transporter (DAT). Bupropion was originally classified as an "atypical" antidepressant because it does not exert the same effects as the classical antidepressants such as Monoamine Oxidase Inhibitors (MAOIs), Tricyclic Antidepressants (TCAs), or Selective Serotonin Reuptake Inhibitors (SSRIs). While it has comparable effectiveness to typical first-line options for the treatment of depression such as SSRIs, bupropion is a unique option for the treatment of MDD as it lacks any clinically relevant serotonergic effects, typical of other mood medications, or any effects on histamine or adrenaline receptors. Lack of activity at these receptors results in a more tolerable side effect profile; bupropion is less likely to cause sexual side effects, sedation, or weight gain as compared to SSRIs or TCAs, for example. When used as an aid to smoking cessation, bupropion is thought to confer its anti-craving and anti-withdrawal effects by inhibiting dopamine reuptake, which is thought to be involved in the reward pathways associated with nicotine, and through the antagonism of the nicotinic acetylcholinergic receptor (AChR), thereby blunting the effects of nicotine. Furthermore, the stimulatory effects produced by bupropion in the central nervous system are similar to nicotine's effects, making low doses of bupropion a suitable option as a nicotine substitute. When used in combination with naltrexone in the marketed product ContraveⓇ for chronic weight management, the two components are thought to have effects on areas of the brain involved in the regulation of food intake. This includes the hypothalamus, which is involved in appetite regulation, and the mesolimbic dopamine circuit, which is involved in reward pathways. Studies have shown that the combined activity of bupropion and naltrexone increase the firing rate of hypothalamic pro-opiomelanocortin (POMC) neurons and blockade of opioid receptor-mediated POMC auto-inhibition, which are associated with a reduction in food intake and increased energy expenditure. This combination was also found to reduce food intake when injected directly into the ventral tegmental area of the mesolimbic circuit in mice, which is an area associated with the regulation of reward pathways. •Mechanism of action (Drug B): By deforming the channel, inhibiting ion-control gating mechanisms, and/or interfering with the release of calcium from the sarcoplasmic reticulum, nicardipine inhibits the influx of extracellular calcium across the myocardial and vascular smooth muscle cell membranes The decrease in intracellular calcium inhibits the contractile processes of the myocardial smooth muscle cells, causing dilation of the coronary and systemic arteries, increased oxygen delivery to the myocardial tissue, decreased total peripheral resistance, decreased systemic blood pressure, and decreased afterload. •Absorption (Drug A): Bupropion is currently available in 3 distinct, but bioequivalent formulations: immediate release (IR), sustained-release (SR), and extended-release (XL). Immediate Release Formulation In humans, following oral administration of bupropion hydrochloride tablets, peak plasma bupropion concentrations are usually achieved within 2 hours. IR formulations provide a short duration of action and are therefore generally dosed three times per day. Sustained Release Formulation In humans, following oral administration of bupropion hydrochloride sustained-release tablets (SR), peak plasma concentration (Cmax) of bupropion is usually achieved within 3 hours. SR formulations provide a 12-hour extended release of medication and are therefore generally dosed twice per day. Extended Release Formulation Following single oral administration of bupropion hydrochloride extended-release tablets (XL) to healthy volunteers, the median time to peak plasma concentrations for bupropion was approximately 5 hours. The presence of food did not affect the peak concentration or area under the curve of bupropion. XL formulations provide a 24-hour extended release of medication and are therefore generally dosed once per day/ In a trial comparing chronic dosing with bupropion hydrochloride extended-release tablets (SR) 150 mg twice daily to bupropion immediate-release formulation 100 mg 3 times daily, the steady state Cmax for bupropion after bupropion hydrochloride sustained-release tablets (SR) administration was approximately 85% of those achieved after bupropion immediate-release formulation administration. Exposure (AUC) to bupropion was equivalent for both formulations. Bioequivalence was also demonstrated for all three major active metabolites (i.e., hydroxybupropion, threohydrobupropion and erythrohydrobupropion) for both Cmax and AUC. Thus, at steady state, bupropion hydrochloride sustained-release tablets (SR) given twice daily, and the immediate-release formulation of bupropion given 3 times daily, are essentially bioequivalent for both bupropion and the 3 quantitatively important metabolites. Furthermore, in a study comparing 14-day dosing with bupropion hydrochloride extended-release tablets (XL), 300 mg once-daily to the immediate-release formulation of bupropion at 100 mg 3 times daily, equivalence was demonstrated for peak plasma concentration and area under the curve for bupropion and the three metabolites (hydroxybupropion, threohydrobupropion, and erythrohydrobupropion). Additionally, in a study comparing 14-day dosing with bupropion hydrochloride extended-release tablets (XL) 300 mg once daily to the sustained-release formulation of bupropion at 150 mg 2 times daily, equivalence was demonstrated for peak plasma concentration and area under the curve for bupropion and the three metabolites. Bupropion hydrochloride extended-release tablets (SR) can be taken with or without food. Bupropion Cmax and AUC were increased by 11% to 35% and 16% to 19%, respectively, when bupropion hydrochloride extended-release tablets (SR) was administered with food to healthy volunteers in three trials. The food effect is not considered clinically significant. Following a single-dose administration of bupropion hydrochloride extended-release tablets (SR) in humans, Cmax of bupropion's metabolite hydroxybupropion occurs approximately 6 hours post-dose and is approximately 10 times the peak level of the parent drug at steady state. The elimination half-life of hydroxybupropion is approximately 20 (±5) hours and its AUC at steady state is about 17 times that of bupropion. The times to peak concentrations for the erythrohydrobupropion and threohydrobupropion metabolites are similar to that of the hydroxybupropion metabolite. However, their elimination half-lives are longer, 33(±10) and 37 (±13) hours, respectively, and steady-state AUCs are 1.5 and 7 times that of bupropion, respectively. •Absorption (Drug B): While nicardipine is completely absorbed, it is subject to saturable first pass metabolism and the systemic bioavailability is about 35% following a 30 mg oral dose at steady state. •Volume of distribution (Drug A): No volume of distribution available •Volume of distribution (Drug B): 8.3 L/kg •Protein binding (Drug A): In vitro tests show that bupropion is 84% bound to human plasma proteins at concentrations up to 200 mcg per mL. The extent of protein binding of the hydroxybupropion metabolite is similar to that for bupropion, whereas the extent of protein binding of the threohydrobupropion metabolite is about half that seen with bupropion. •Protein binding (Drug B): >95% •Metabolism (Drug A): Bupropion is extensively metabolized in humans. Three metabolites are active: hydroxybupropion, which is formed via hydroxylation of the tert-butyl group of bupropion, and the amino-alcohol isomers, threohydrobupropion and erythrohydrobupropion, which are formed via reduction of the carbonyl group. In vitro findings suggest that CYP2B6 is the principal isoenzyme involved in the formation of hydroxybupropion, while cytochrome P450 enzymes are not involved in the formation of threohydrobupropion. Hydroxybupropion has been shown to have the same affinity as bupropion for the norepinephrine transporter (NET) but approximately 50% of its antidepressant activity despite reaching concentrations of ~10-fold higher than that of the parent drug. Oxidation of the bupropion side chain results in the formation of a glycine conjugate of meta-chlorobenzoic acid, which is then excreted as the major urinary metabolite. The potency and toxicity of the metabolites relative to bupropion have not been fully characterized. However, it has been demonstrated in an antidepressant screening test in mice that hydroxybupropion is one-half as potent as bupropion, while threohydrobupropion and erythrohydrobupropion are 5-fold less potent than bupropion. This may be of clinical importance because the plasma concentrations of the metabolites are as high as or higher than those of bupropion. Bupropion and its metabolites exhibit linear kinetics following chronic administration of 300 to 450 mg per day. •Metabolism (Drug B): Nicardipine HCl is metabolized extensively by the liver. •Route of elimination (Drug A): Bupropion is extensively metabolized in humans. Oxidation of the bupropion side chain results in the formation of a glycine conjugate of metachlorobenzoic acid, which is then excreted as the major urinary metabolite. Following oral administration of 200 mg of 14C-bupropion in humans, 87% and 10% of the radioactive dose were recovered in the urine and feces, respectively. However, the fraction of the oral dose of bupropion excreted unchanged was only 0.5%, a finding consistent with the extensive metabolism of bupropion. •Route of elimination (Drug B): Nicardipine has been shown to be rapidly and extensively metabolized by the liver. •Half-life (Drug A): 24 hours •Half-life (Drug B): 8.6 hours •Clearance (Drug A): No clearance available •Clearance (Drug B): 0.4 L/hr∙kg [Following infusion] •Toxicity (Drug A): Symptoms of overdose include seizures, hallucinations, loss of consciousness, tachycardia, and cardiac arrest. •Toxicity (Drug B): Oral LD 50 Rat = 184 mg/kg, Oral LD 50 Mouse = 322 mg/kg •Brand Names (Drug A): Aplenzin, Auvelity, Budeprion, Contrave, Forfivo, Wellbutrin, Zyban •Brand Names (Drug B): Cardene •Synonyms (Drug A): No synonyms listed •Synonyms (Drug B): No synonyms listed •Summary (Drug A): Bupropion is a norepinephrine and dopamine reuptake inhibitor used in the treatment of major depressive disorder (MDD), seasonal affective disorder (SAD), and as an aid to smoking cessation. •Summary (Drug B): Nicardipine is a calcium channel blocker used for the short-term treatment of hypertension and chronic stable angina.

The subject drug is a strong inhibitor of CYP2C9 while the affected drug is metabolized by CYP2C9. Concomitant administration will lead to an increase in serum concentrations of the affected drug, leading to accumulation of the drug and an increase in the risk and severity of adverse effects. The severity of the interaction is major.

Question: Does Bupropion and Nicardipine interact? Information: •Drug A: Bupropion •Drug B: Nicardipine •Severity: MAJOR •Description: The metabolism of Bupropion can be decreased when combined with Nicardipine. •Extended Description: The subject drug is a strong inhibitor of CYP2C9 while the affected drug is metabolized by CYP2C9. Concomitant administration will lead to an increase in serum concentrations of the affected drug, leading to accumulation of the drug and an increase in the risk and severity of adverse effects. •Indication (Drug A): Bupropion is indicated for the treatment of major depressive disorder (MDD), seasonal affective disorder (SAD), and as an aid to smoking cessation. When used in combination with naltrexone as the marketed product ContraveⓇ, bupropion is indicated as an adjunct to a reduced-calorie diet and increased physical activity for chronic weight management in adults with an initial body mass index (BMI) of: 30 kg/m^2 or greater (obese) or 27 kg/m^2 or greater (overweight) in the presence of at least one weight-related comorbid condition (e.g., hypertension, type 2 diabetes mellitus, or dyslipidemia). Bupropion is also used off-label as a first-line treatment in patients with ADHD and comorbid bipolar disorder when used as an adjunct to mood stabilizers. •Indication (Drug B): Used for the management of patients with chronic stable angina and for the treatment of hypertension. •Pharmacodynamics (Drug A): Bupropion is chemically unrelated to tricyclic, tetracyclic, selective serotonin re-uptake inhibitors, or other known antidepressant agents. Compared to classical tricyclic antidepressants, Bupropion is a relatively weak inhibitor of the neuronal uptake of norepinephrine and dopamine. In addition, Bupropion does not inhibit monoamine oxidase. Bupropion has been found to be essentially inactive at the serotonin transporter (SERT)(IC50 >10 000 nM), however both bupropion and its primary metabolite hydroxybupropion have been found to block the function of cation-selective serotonin type 3A receptors (5-HT3ARs). Bupropion produces dose-related central nervous system (CNS) stimulant effects in animals, as evidenced by increased locomotor activity, increased rates of responding in various schedule-controlled operant behaviour tasks, and, at high doses, induction of mild stereotyped behaviour. Due to these stimulant effects and selective activity at dopamine and norepinephrine receptors, bupropion has been identified as having an abuse potential. Bupropion has a similar structure to the controlled substance Cathinone, and has been identified as having mild amphetamine-like activity, particularly when inhaled or injected. Bupropion is also known to lower the seizure threshold, making any pre-existing seizure conditions a contraindication to its use. This risk is exacerbated when bupropion is combined with other drugs or substances that lower the seizure threshold, such as cocaine, or in clinical situations that would increase the risk of a seizure such as abrupt alcohol or benzodiazepine withdrawal. As norepinephrine has been shown to have anticonvulsant properties, bupropion's inhibitory effects on NET are thought to contribute to its pro-convulsant activity. Bupropion has been shown to increase blood pressure and pose a risk for exacerbation of unmanaged or pre-existing hypertension, however, clinical trials of bupropion in smokers with CVD have not identified an increased incidence of CV events including stroke or heart attack. In clinical trials, the mean increase in systolic blood pressure associated with the use of bupropion was found to be 1.3 mmHg. •Pharmacodynamics (Drug B): Nicardipine, a dihydropyridine calcium-channel blocker, is used alone or with an angiotensin-converting enzyme inhibitor, to treat hypertension, chronic stable angina pectoris, and Prinzmetal's variant angina. Nicardipine is similar to other peripheral vasodilators. Nicardipine inhibits the influx of extra cellular calcium across the myocardial and vascular smooth muscle cell membranes possibly by deforming the channel, inhibiting ion-control gating mechanisms, and/or interfering with the release of calcium from the sarcoplasmic reticulum. The decrease in intracellular calcium inhibits the contractile processes of the myocardial smooth muscle cells, causing dilation of the coronary and systemic arteries, increased oxygen delivery to the myocardial tissue, decreased total peripheral resistance, decreased systemic blood pressure, and decreased afterload. •Mechanism of action (Drug A): Bupropion is a norepinephrine/dopamine-reuptake inhibitor (NDRI) that exerts its pharmacological effects by weakly inhibiting the enzymes involved in the uptake of the neurotransmitters norepinephrine and dopamine from the synaptic cleft, therefore prolonging their duration of action within the neuronal synapse and the downstream effects of these neurotransmitters. More specifically, bupropion binds to the norepinephrine transporter (NET) and the dopamine transporter (DAT). Bupropion was originally classified as an "atypical" antidepressant because it does not exert the same effects as the classical antidepressants such as Monoamine Oxidase Inhibitors (MAOIs), Tricyclic Antidepressants (TCAs), or Selective Serotonin Reuptake Inhibitors (SSRIs). While it has comparable effectiveness to typical first-line options for the treatment of depression such as SSRIs, bupropion is a unique option for the treatment of MDD as it lacks any clinically relevant serotonergic effects, typical of other mood medications, or any effects on histamine or adrenaline receptors. Lack of activity at these receptors results in a more tolerable side effect profile; bupropion is less likely to cause sexual side effects, sedation, or weight gain as compared to SSRIs or TCAs, for example. When used as an aid to smoking cessation, bupropion is thought to confer its anti-craving and anti-withdrawal effects by inhibiting dopamine reuptake, which is thought to be involved in the reward pathways associated with nicotine, and through the antagonism of the nicotinic acetylcholinergic receptor (AChR), thereby blunting the effects of nicotine. Furthermore, the stimulatory effects produced by bupropion in the central nervous system are similar to nicotine's effects, making low doses of bupropion a suitable option as a nicotine substitute. When used in combination with naltrexone in the marketed product ContraveⓇ for chronic weight management, the two components are thought to have effects on areas of the brain involved in the regulation of food intake. This includes the hypothalamus, which is involved in appetite regulation, and the mesolimbic dopamine circuit, which is involved in reward pathways. Studies have shown that the combined activity of bupropion and naltrexone increase the firing rate of hypothalamic pro-opiomelanocortin (POMC) neurons and blockade of opioid receptor-mediated POMC auto-inhibition, which are associated with a reduction in food intake and increased energy expenditure. This combination was also found to reduce food intake when injected directly into the ventral tegmental area of the mesolimbic circuit in mice, which is an area associated with the regulation of reward pathways. •Mechanism of action (Drug B): By deforming the channel, inhibiting ion-control gating mechanisms, and/or interfering with the release of calcium from the sarcoplasmic reticulum, nicardipine inhibits the influx of extracellular calcium across the myocardial and vascular smooth muscle cell membranes The decrease in intracellular calcium inhibits the contractile processes of the myocardial smooth muscle cells, causing dilation of the coronary and systemic arteries, increased oxygen delivery to the myocardial tissue, decreased total peripheral resistance, decreased systemic blood pressure, and decreased afterload. •Absorption (Drug A): Bupropion is currently available in 3 distinct, but bioequivalent formulations: immediate release (IR), sustained-release (SR), and extended-release (XL). Immediate Release Formulation In humans, following oral administration of bupropion hydrochloride tablets, peak plasma bupropion concentrations are usually achieved within 2 hours. IR formulations provide a short duration of action and are therefore generally dosed three times per day. Sustained Release Formulation In humans, following oral administration of bupropion hydrochloride sustained-release tablets (SR), peak plasma concentration (Cmax) of bupropion is usually achieved within 3 hours. SR formulations provide a 12-hour extended release of medication and are therefore generally dosed twice per day. Extended Release Formulation Following single oral administration of bupropion hydrochloride extended-release tablets (XL) to healthy volunteers, the median time to peak plasma concentrations for bupropion was approximately 5 hours. The presence of food did not affect the peak concentration or area under the curve of bupropion. XL formulations provide a 24-hour extended release of medication and are therefore generally dosed once per day/ In a trial comparing chronic dosing with bupropion hydrochloride extended-release tablets (SR) 150 mg twice daily to bupropion immediate-release formulation 100 mg 3 times daily, the steady state Cmax for bupropion after bupropion hydrochloride sustained-release tablets (SR) administration was approximately 85% of those achieved after bupropion immediate-release formulation administration. Exposure (AUC) to bupropion was equivalent for both formulations. Bioequivalence was also demonstrated for all three major active metabolites (i.e., hydroxybupropion, threohydrobupropion and erythrohydrobupropion) for both Cmax and AUC. Thus, at steady state, bupropion hydrochloride sustained-release tablets (SR) given twice daily, and the immediate-release formulation of bupropion given 3 times daily, are essentially bioequivalent for both bupropion and the 3 quantitatively important metabolites. Furthermore, in a study comparing 14-day dosing with bupropion hydrochloride extended-release tablets (XL), 300 mg once-daily to the immediate-release formulation of bupropion at 100 mg 3 times daily, equivalence was demonstrated for peak plasma concentration and area under the curve for bupropion and the three metabolites (hydroxybupropion, threohydrobupropion, and erythrohydrobupropion). Additionally, in a study comparing 14-day dosing with bupropion hydrochloride extended-release tablets (XL) 300 mg once daily to the sustained-release formulation of bupropion at 150 mg 2 times daily, equivalence was demonstrated for peak plasma concentration and area under the curve for bupropion and the three metabolites. Bupropion hydrochloride extended-release tablets (SR) can be taken with or without food. Bupropion Cmax and AUC were increased by 11% to 35% and 16% to 19%, respectively, when bupropion hydrochloride extended-release tablets (SR) was administered with food to healthy volunteers in three trials. The food effect is not considered clinically significant. Following a single-dose administration of bupropion hydrochloride extended-release tablets (SR) in humans, Cmax of bupropion's metabolite hydroxybupropion occurs approximately 6 hours post-dose and is approximately 10 times the peak level of the parent drug at steady state. The elimination half-life of hydroxybupropion is approximately 20 (±5) hours and its AUC at steady state is about 17 times that of bupropion. The times to peak concentrations for the erythrohydrobupropion and threohydrobupropion metabolites are similar to that of the hydroxybupropion metabolite. However, their elimination half-lives are longer, 33(±10) and 37 (±13) hours, respectively, and steady-state AUCs are 1.5 and 7 times that of bupropion, respectively. •Absorption (Drug B): While nicardipine is completely absorbed, it is subject to saturable first pass metabolism and the systemic bioavailability is about 35% following a 30 mg oral dose at steady state. •Volume of distribution (Drug A): No volume of distribution available •Volume of distribution (Drug B): 8.3 L/kg •Protein binding (Drug A): In vitro tests show that bupropion is 84% bound to human plasma proteins at concentrations up to 200 mcg per mL. The extent of protein binding of the hydroxybupropion metabolite is similar to that for bupropion, whereas the extent of protein binding of the threohydrobupropion metabolite is about half that seen with bupropion. •Protein binding (Drug B): >95% •Metabolism (Drug A): Bupropion is extensively metabolized in humans. Three metabolites are active: hydroxybupropion, which is formed via hydroxylation of the tert-butyl group of bupropion, and the amino-alcohol isomers, threohydrobupropion and erythrohydrobupropion, which are formed via reduction of the carbonyl group. In vitro findings suggest that CYP2B6 is the principal isoenzyme involved in the formation of hydroxybupropion, while cytochrome P450 enzymes are not involved in the formation of threohydrobupropion. Hydroxybupropion has been shown to have the same affinity as bupropion for the norepinephrine transporter (NET) but approximately 50% of its antidepressant activity despite reaching concentrations of ~10-fold higher than that of the parent drug. Oxidation of the bupropion side chain results in the formation of a glycine conjugate of meta-chlorobenzoic acid, which is then excreted as the major urinary metabolite. The potency and toxicity of the metabolites relative to bupropion have not been fully characterized. However, it has been demonstrated in an antidepressant screening test in mice that hydroxybupropion is one-half as potent as bupropion, while threohydrobupropion and erythrohydrobupropion are 5-fold less potent than bupropion. This may be of clinical importance because the plasma concentrations of the metabolites are as high as or higher than those of bupropion. Bupropion and its metabolites exhibit linear kinetics following chronic administration of 300 to 450 mg per day. •Metabolism (Drug B): Nicardipine HCl is metabolized extensively by the liver. •Route of elimination (Drug A): Bupropion is extensively metabolized in humans. Oxidation of the bupropion side chain results in the formation of a glycine conjugate of metachlorobenzoic acid, which is then excreted as the major urinary metabolite. Following oral administration of 200 mg of 14C-bupropion in humans, 87% and 10% of the radioactive dose were recovered in the urine and feces, respectively. However, the fraction of the oral dose of bupropion excreted unchanged was only 0.5%, a finding consistent with the extensive metabolism of bupropion. •Route of elimination (Drug B): Nicardipine has been shown to be rapidly and extensively metabolized by the liver. •Half-life (Drug A): 24 hours •Half-life (Drug B): 8.6 hours •Clearance (Drug A): No clearance available •Clearance (Drug B): 0.4 L/hr∙kg [Following infusion] •Toxicity (Drug A): Symptoms of overdose include seizures, hallucinations, loss of consciousness, tachycardia, and cardiac arrest. •Toxicity (Drug B): Oral LD 50 Rat = 184 mg/kg, Oral LD 50 Mouse = 322 mg/kg •Brand Names (Drug A): Aplenzin, Auvelity, Budeprion, Contrave, Forfivo, Wellbutrin, Zyban •Brand Names (Drug B): Cardene •Synonyms (Drug A): No synonyms listed •Synonyms (Drug B): No synonyms listed •Summary (Drug A): Bupropion is a norepinephrine and dopamine reuptake inhibitor used in the treatment of major depressive disorder (MDD), seasonal affective disorder (SAD), and as an aid to smoking cessation. •Summary (Drug B): Nicardipine is a calcium channel blocker used for the short-term treatment of hypertension and chronic stable angina. Output: The subject drug is a strong inhibitor of CYP2C9 while the affected drug is metabolized by CYP2C9. Concomitant administration will lead to an increase in serum concentrations of the affected drug, leading to accumulation of the drug and an increase in the risk and severity of adverse effects. The severity of the interaction is major.

Does Bupropion and Nicergoline interact?

•Drug A: Bupropion •Drug B: Nicergoline •Severity: MAJOR •Description: The metabolism of Nicergoline can be decreased when combined with Bupropion. •Extended Description: The subject drug is a strong CYP2D6 inhibitor and the affected drug is metabolized by CYP2D6. Concomitant administration may decrease the metabolism of the affected drug, which could increase serum concentrations as well as the risk and severity of adverse effects. •Indication (Drug A): Bupropion is indicated for the treatment of major depressive disorder (MDD), seasonal affective disorder (SAD), and as an aid to smoking cessation. When used in combination with naltrexone as the marketed product ContraveⓇ, bupropion is indicated as an adjunct to a reduced-calorie diet and increased physical activity for chronic weight management in adults with an initial body mass index (BMI) of: 30 kg/m^2 or greater (obese) or 27 kg/m^2 or greater (overweight) in the presence of at least one weight-related comorbid condition (e.g., hypertension, type 2 diabetes mellitus, or dyslipidemia). Bupropion is also used off-label as a first-line treatment in patients with ADHD and comorbid bipolar disorder when used as an adjunct to mood stabilizers. •Indication (Drug B): For the treatment of senile dementia, migraines of vascular origin, transient ischemia, platelet hyper-aggregability, and macular degeneration. •Pharmacodynamics (Drug A): Bupropion is chemically unrelated to tricyclic, tetracyclic, selective serotonin re-uptake inhibitors, or other known antidepressant agents. Compared to classical tricyclic antidepressants, Bupropion is a relatively weak inhibitor of the neuronal uptake of norepinephrine and dopamine. In addition, Bupropion does not inhibit monoamine oxidase. Bupropion has been found to be essentially inactive at the serotonin transporter (SERT)(IC50 >10 000 nM), however both bupropion and its primary metabolite hydroxybupropion have been found to block the function of cation-selective serotonin type 3A receptors (5-HT3ARs). Bupropion produces dose-related central nervous system (CNS) stimulant effects in animals, as evidenced by increased locomotor activity, increased rates of responding in various schedule-controlled operant behaviour tasks, and, at high doses, induction of mild stereotyped behaviour. Due to these stimulant effects and selective activity at dopamine and norepinephrine receptors, bupropion has been identified as having an abuse potential. Bupropion has a similar structure to the controlled substance Cathinone, and has been identified as having mild amphetamine-like activity, particularly when inhaled or injected. Bupropion is also known to lower the seizure threshold, making any pre-existing seizure conditions a contraindication to its use. This risk is exacerbated when bupropion is combined with other drugs or substances that lower the seizure threshold, such as cocaine, or in clinical situations that would increase the risk of a seizure such as abrupt alcohol or benzodiazepine withdrawal. As norepinephrine has been shown to have anticonvulsant properties, bupropion's inhibitory effects on NET are thought to contribute to its pro-convulsant activity. Bupropion has been shown to increase blood pressure and pose a risk for exacerbation of unmanaged or pre-existing hypertension, however, clinical trials of bupropion in smokers with CVD have not identified an increased incidence of CV events including stroke or heart attack. In clinical trials, the mean increase in systolic blood pressure associated with the use of bupropion was found to be 1.3 mmHg. •Pharmacodynamics (Drug B): Nicergoline is a potent vasodilator (improves brain blood flow). On the cerebral level it prompts a lowering of vascular resistance, an increase in arterial flow and stimulates the use of oxygen and glucose. Nicergoline also improves blood circulation in the lungs and limbs and has been shown to inhibit blood platelet aggregation. •Mechanism of action (Drug A): Bupropion is a norepinephrine/dopamine-reuptake inhibitor (NDRI) that exerts its pharmacological effects by weakly inhibiting the enzymes involved in the uptake of the neurotransmitters norepinephrine and dopamine from the synaptic cleft, therefore prolonging their duration of action within the neuronal synapse and the downstream effects of these neurotransmitters. More specifically, bupropion binds to the norepinephrine transporter (NET) and the dopamine transporter (DAT). Bupropion was originally classified as an "atypical" antidepressant because it does not exert the same effects as the classical antidepressants such as Monoamine Oxidase Inhibitors (MAOIs), Tricyclic Antidepressants (TCAs), or Selective Serotonin Reuptake Inhibitors (SSRIs). While it has comparable effectiveness to typical first-line options for the treatment of depression such as SSRIs, bupropion is a unique option for the treatment of MDD as it lacks any clinically relevant serotonergic effects, typical of other mood medications, or any effects on histamine or adrenaline receptors. Lack of activity at these receptors results in a more tolerable side effect profile; bupropion is less likely to cause sexual side effects, sedation, or weight gain as compared to SSRIs or TCAs, for example. When used as an aid to smoking cessation, bupropion is thought to confer its anti-craving and anti-withdrawal effects by inhibiting dopamine reuptake, which is thought to be involved in the reward pathways associated with nicotine, and through the antagonism of the nicotinic acetylcholinergic receptor (AChR), thereby blunting the effects of nicotine. Furthermore, the stimulatory effects produced by bupropion in the central nervous system are similar to nicotine's effects, making low doses of bupropion a suitable option as a nicotine substitute. When used in combination with naltrexone in the marketed product ContraveⓇ for chronic weight management, the two components are thought to have effects on areas of the brain involved in the regulation of food intake. This includes the hypothalamus, which is involved in appetite regulation, and the mesolimbic dopamine circuit, which is involved in reward pathways. Studies have shown that the combined activity of bupropion and naltrexone increase the firing rate of hypothalamic pro-opiomelanocortin (POMC) neurons and blockade of opioid receptor-mediated POMC auto-inhibition, which are associated with a reduction in food intake and increased energy expenditure. This combination was also found to reduce food intake when injected directly into the ventral tegmental area of the mesolimbic circuit in mice, which is an area associated with the regulation of reward pathways. •Mechanism of action (Drug B): Nicergoline acts by inhibiting the postsynaptic alpha(1)-adrenoceptors on vascular smooth muscle. This inhibits the vasoconstrictor effect of circulating and locally released catecholamines (epinephrine and norepinephrine), resulting in peripheral vasodilation. Therefore the mechanism of Nicergoline is to increase vascular circulation in the brain, thereby enhancing the transmission of nerve signals across the nerve fibres, which secrete acetylcholine as a neural transmitter. •Absorption (Drug A): Bupropion is currently available in 3 distinct, but bioequivalent formulations: immediate release (IR), sustained-release (SR), and extended-release (XL). Immediate Release Formulation In humans, following oral administration of bupropion hydrochloride tablets, peak plasma bupropion concentrations are usually achieved within 2 hours. IR formulations provide a short duration of action and are therefore generally dosed three times per day. Sustained Release Formulation In humans, following oral administration of bupropion hydrochloride sustained-release tablets (SR), peak plasma concentration (Cmax) of bupropion is usually achieved within 3 hours. SR formulations provide a 12-hour extended release of medication and are therefore generally dosed twice per day. Extended Release Formulation Following single oral administration of bupropion hydrochloride extended-release tablets (XL) to healthy volunteers, the median time to peak plasma concentrations for bupropion was approximately 5 hours. The presence of food did not affect the peak concentration or area under the curve of bupropion. XL formulations provide a 24-hour extended release of medication and are therefore generally dosed once per day/ In a trial comparing chronic dosing with bupropion hydrochloride extended-release tablets (SR) 150 mg twice daily to bupropion immediate-release formulation 100 mg 3 times daily, the steady state Cmax for bupropion after bupropion hydrochloride sustained-release tablets (SR) administration was approximately 85% of those achieved after bupropion immediate-release formulation administration. Exposure (AUC) to bupropion was equivalent for both formulations. Bioequivalence was also demonstrated for all three major active metabolites (i.e., hydroxybupropion, threohydrobupropion and erythrohydrobupropion) for both Cmax and AUC. Thus, at steady state, bupropion hydrochloride sustained-release tablets (SR) given twice daily, and the immediate-release formulation of bupropion given 3 times daily, are essentially bioequivalent for both bupropion and the 3 quantitatively important metabolites. Furthermore, in a study comparing 14-day dosing with bupropion hydrochloride extended-release tablets (XL), 300 mg once-daily to the immediate-release formulation of bupropion at 100 mg 3 times daily, equivalence was demonstrated for peak plasma concentration and area under the curve for bupropion and the three metabolites (hydroxybupropion, threohydrobupropion, and erythrohydrobupropion). Additionally, in a study comparing 14-day dosing with bupropion hydrochloride extended-release tablets (XL) 300 mg once daily to the sustained-release formulation of bupropion at 150 mg 2 times daily, equivalence was demonstrated for peak plasma concentration and area under the curve for bupropion and the three metabolites. Bupropion hydrochloride extended-release tablets (SR) can be taken with or without food. Bupropion Cmax and AUC were increased by 11% to 35% and 16% to 19%, respectively, when bupropion hydrochloride extended-release tablets (SR) was administered with food to healthy volunteers in three trials. The food effect is not considered clinically significant. Following a single-dose administration of bupropion hydrochloride extended-release tablets (SR) in humans, Cmax of bupropion's metabolite hydroxybupropion occurs approximately 6 hours post-dose and is approximately 10 times the peak level of the parent drug at steady state. The elimination half-life of hydroxybupropion is approximately 20 (±5) hours and its AUC at steady state is about 17 times that of bupropion. The times to peak concentrations for the erythrohydrobupropion and threohydrobupropion metabolites are similar to that of the hydroxybupropion metabolite. However, their elimination half-lives are longer, 33(±10) and 37 (±13) hours, respectively, and steady-state AUCs are 1.5 and 7 times that of bupropion, respectively. •Absorption (Drug B): No absorption available •Volume of distribution (Drug A): No volume of distribution available •Volume of distribution (Drug B): No volume of distribution available •Protein binding (Drug A): In vitro tests show that bupropion is 84% bound to human plasma proteins at concentrations up to 200 mcg per mL. The extent of protein binding of the hydroxybupropion metabolite is similar to that for bupropion, whereas the extent of protein binding of the threohydrobupropion metabolite is about half that seen with bupropion. •Protein binding (Drug B): No protein binding available •Metabolism (Drug A): Bupropion is extensively metabolized in humans. Three metabolites are active: hydroxybupropion, which is formed via hydroxylation of the tert-butyl group of bupropion, and the amino-alcohol isomers, threohydrobupropion and erythrohydrobupropion, which are formed via reduction of the carbonyl group. In vitro findings suggest that CYP2B6 is the principal isoenzyme involved in the formation of hydroxybupropion, while cytochrome P450 enzymes are not involved in the formation of threohydrobupropion. Hydroxybupropion has been shown to have the same affinity as bupropion for the norepinephrine transporter (NET) but approximately 50% of its antidepressant activity despite reaching concentrations of ~10-fold higher than that of the parent drug. Oxidation of the bupropion side chain results in the formation of a glycine conjugate of meta-chlorobenzoic acid, which is then excreted as the major urinary metabolite. The potency and toxicity of the metabolites relative to bupropion have not been fully characterized. However, it has been demonstrated in an antidepressant screening test in mice that hydroxybupropion is one-half as potent as bupropion, while threohydrobupropion and erythrohydrobupropion are 5-fold less potent than bupropion. This may be of clinical importance because the plasma concentrations of the metabolites are as high as or higher than those of bupropion. Bupropion and its metabolites exhibit linear kinetics following chronic administration of 300 to 450 mg per day. •Metabolism (Drug B): No metabolism available •Route of elimination (Drug A): Bupropion is extensively metabolized in humans. Oxidation of the bupropion side chain results in the formation of a glycine conjugate of metachlorobenzoic acid, which is then excreted as the major urinary metabolite. Following oral administration of 200 mg of 14C-bupropion in humans, 87% and 10% of the radioactive dose were recovered in the urine and feces, respectively. However, the fraction of the oral dose of bupropion excreted unchanged was only 0.5%, a finding consistent with the extensive metabolism of bupropion. •Route of elimination (Drug B): No route of elimination available •Half-life (Drug A): 24 hours •Half-life (Drug B): No half-life available •Clearance (Drug A): No clearance available •Clearance (Drug B): No clearance available •Toxicity (Drug A): Symptoms of overdose include seizures, hallucinations, loss of consciousness, tachycardia, and cardiac arrest. •Toxicity (Drug B): No toxicity available •Brand Names (Drug A): Aplenzin, Auvelity, Budeprion, Contrave, Forfivo, Wellbutrin, Zyban •Brand Names (Drug B): No brand names available •Synonyms (Drug A): No synonyms listed •Synonyms (Drug B): Nicergolin Nicergolina Nicergoline Nicergolinum •Summary (Drug A): Bupropion is a norepinephrine and dopamine reuptake inhibitor used in the treatment of major depressive disorder (MDD), seasonal affective disorder (SAD), and as an aid to smoking cessation. •Summary (Drug B): Nicergoline is an ergot derivative use for the treatment of symptoms associated with cerebrovascular abnormalities.

The subject drug is a strong CYP2D6 inhibitor and the affected drug is metabolized by CYP2D6. Concomitant administration may decrease the metabolism of the affected drug, which could increase serum concentrations as well as the risk and severity of adverse effects. The severity of the interaction is major.

Question: Does Bupropion and Nicergoline interact? Information: •Drug A: Bupropion •Drug B: Nicergoline •Severity: MAJOR •Description: The metabolism of Nicergoline can be decreased when combined with Bupropion. •Extended Description: The subject drug is a strong CYP2D6 inhibitor and the affected drug is metabolized by CYP2D6. Concomitant administration may decrease the metabolism of the affected drug, which could increase serum concentrations as well as the risk and severity of adverse effects. •Indication (Drug A): Bupropion is indicated for the treatment of major depressive disorder (MDD), seasonal affective disorder (SAD), and as an aid to smoking cessation. When used in combination with naltrexone as the marketed product ContraveⓇ, bupropion is indicated as an adjunct to a reduced-calorie diet and increased physical activity for chronic weight management in adults with an initial body mass index (BMI) of: 30 kg/m^2 or greater (obese) or 27 kg/m^2 or greater (overweight) in the presence of at least one weight-related comorbid condition (e.g., hypertension, type 2 diabetes mellitus, or dyslipidemia). Bupropion is also used off-label as a first-line treatment in patients with ADHD and comorbid bipolar disorder when used as an adjunct to mood stabilizers. •Indication (Drug B): For the treatment of senile dementia, migraines of vascular origin, transient ischemia, platelet hyper-aggregability, and macular degeneration. •Pharmacodynamics (Drug A): Bupropion is chemically unrelated to tricyclic, tetracyclic, selective serotonin re-uptake inhibitors, or other known antidepressant agents. Compared to classical tricyclic antidepressants, Bupropion is a relatively weak inhibitor of the neuronal uptake of norepinephrine and dopamine. In addition, Bupropion does not inhibit monoamine oxidase. Bupropion has been found to be essentially inactive at the serotonin transporter (SERT)(IC50 >10 000 nM), however both bupropion and its primary metabolite hydroxybupropion have been found to block the function of cation-selective serotonin type 3A receptors (5-HT3ARs). Bupropion produces dose-related central nervous system (CNS) stimulant effects in animals, as evidenced by increased locomotor activity, increased rates of responding in various schedule-controlled operant behaviour tasks, and, at high doses, induction of mild stereotyped behaviour. Due to these stimulant effects and selective activity at dopamine and norepinephrine receptors, bupropion has been identified as having an abuse potential. Bupropion has a similar structure to the controlled substance Cathinone, and has been identified as having mild amphetamine-like activity, particularly when inhaled or injected. Bupropion is also known to lower the seizure threshold, making any pre-existing seizure conditions a contraindication to its use. This risk is exacerbated when bupropion is combined with other drugs or substances that lower the seizure threshold, such as cocaine, or in clinical situations that would increase the risk of a seizure such as abrupt alcohol or benzodiazepine withdrawal. As norepinephrine has been shown to have anticonvulsant properties, bupropion's inhibitory effects on NET are thought to contribute to its pro-convulsant activity. Bupropion has been shown to increase blood pressure and pose a risk for exacerbation of unmanaged or pre-existing hypertension, however, clinical trials of bupropion in smokers with CVD have not identified an increased incidence of CV events including stroke or heart attack. In clinical trials, the mean increase in systolic blood pressure associated with the use of bupropion was found to be 1.3 mmHg. •Pharmacodynamics (Drug B): Nicergoline is a potent vasodilator (improves brain blood flow). On the cerebral level it prompts a lowering of vascular resistance, an increase in arterial flow and stimulates the use of oxygen and glucose. Nicergoline also improves blood circulation in the lungs and limbs and has been shown to inhibit blood platelet aggregation. •Mechanism of action (Drug A): Bupropion is a norepinephrine/dopamine-reuptake inhibitor (NDRI) that exerts its pharmacological effects by weakly inhibiting the enzymes involved in the uptake of the neurotransmitters norepinephrine and dopamine from the synaptic cleft, therefore prolonging their duration of action within the neuronal synapse and the downstream effects of these neurotransmitters. More specifically, bupropion binds to the norepinephrine transporter (NET) and the dopamine transporter (DAT). Bupropion was originally classified as an "atypical" antidepressant because it does not exert the same effects as the classical antidepressants such as Monoamine Oxidase Inhibitors (MAOIs), Tricyclic Antidepressants (TCAs), or Selective Serotonin Reuptake Inhibitors (SSRIs). While it has comparable effectiveness to typical first-line options for the treatment of depression such as SSRIs, bupropion is a unique option for the treatment of MDD as it lacks any clinically relevant serotonergic effects, typical of other mood medications, or any effects on histamine or adrenaline receptors. Lack of activity at these receptors results in a more tolerable side effect profile; bupropion is less likely to cause sexual side effects, sedation, or weight gain as compared to SSRIs or TCAs, for example. When used as an aid to smoking cessation, bupropion is thought to confer its anti-craving and anti-withdrawal effects by inhibiting dopamine reuptake, which is thought to be involved in the reward pathways associated with nicotine, and through the antagonism of the nicotinic acetylcholinergic receptor (AChR), thereby blunting the effects of nicotine. Furthermore, the stimulatory effects produced by bupropion in the central nervous system are similar to nicotine's effects, making low doses of bupropion a suitable option as a nicotine substitute. When used in combination with naltrexone in the marketed product ContraveⓇ for chronic weight management, the two components are thought to have effects on areas of the brain involved in the regulation of food intake. This includes the hypothalamus, which is involved in appetite regulation, and the mesolimbic dopamine circuit, which is involved in reward pathways. Studies have shown that the combined activity of bupropion and naltrexone increase the firing rate of hypothalamic pro-opiomelanocortin (POMC) neurons and blockade of opioid receptor-mediated POMC auto-inhibition, which are associated with a reduction in food intake and increased energy expenditure. This combination was also found to reduce food intake when injected directly into the ventral tegmental area of the mesolimbic circuit in mice, which is an area associated with the regulation of reward pathways. •Mechanism of action (Drug B): Nicergoline acts by inhibiting the postsynaptic alpha(1)-adrenoceptors on vascular smooth muscle. This inhibits the vasoconstrictor effect of circulating and locally released catecholamines (epinephrine and norepinephrine), resulting in peripheral vasodilation. Therefore the mechanism of Nicergoline is to increase vascular circulation in the brain, thereby enhancing the transmission of nerve signals across the nerve fibres, which secrete acetylcholine as a neural transmitter. •Absorption (Drug A): Bupropion is currently available in 3 distinct, but bioequivalent formulations: immediate release (IR), sustained-release (SR), and extended-release (XL). Immediate Release Formulation In humans, following oral administration of bupropion hydrochloride tablets, peak plasma bupropion concentrations are usually achieved within 2 hours. IR formulations provide a short duration of action and are therefore generally dosed three times per day. Sustained Release Formulation In humans, following oral administration of bupropion hydrochloride sustained-release tablets (SR), peak plasma concentration (Cmax) of bupropion is usually achieved within 3 hours. SR formulations provide a 12-hour extended release of medication and are therefore generally dosed twice per day. Extended Release Formulation Following single oral administration of bupropion hydrochloride extended-release tablets (XL) to healthy volunteers, the median time to peak plasma concentrations for bupropion was approximately 5 hours. The presence of food did not affect the peak concentration or area under the curve of bupropion. XL formulations provide a 24-hour extended release of medication and are therefore generally dosed once per day/ In a trial comparing chronic dosing with bupropion hydrochloride extended-release tablets (SR) 150 mg twice daily to bupropion immediate-release formulation 100 mg 3 times daily, the steady state Cmax for bupropion after bupropion hydrochloride sustained-release tablets (SR) administration was approximately 85% of those achieved after bupropion immediate-release formulation administration. Exposure (AUC) to bupropion was equivalent for both formulations. Bioequivalence was also demonstrated for all three major active metabolites (i.e., hydroxybupropion, threohydrobupropion and erythrohydrobupropion) for both Cmax and AUC. Thus, at steady state, bupropion hydrochloride sustained-release tablets (SR) given twice daily, and the immediate-release formulation of bupropion given 3 times daily, are essentially bioequivalent for both bupropion and the 3 quantitatively important metabolites. Furthermore, in a study comparing 14-day dosing with bupropion hydrochloride extended-release tablets (XL), 300 mg once-daily to the immediate-release formulation of bupropion at 100 mg 3 times daily, equivalence was demonstrated for peak plasma concentration and area under the curve for bupropion and the three metabolites (hydroxybupropion, threohydrobupropion, and erythrohydrobupropion). Additionally, in a study comparing 14-day dosing with bupropion hydrochloride extended-release tablets (XL) 300 mg once daily to the sustained-release formulation of bupropion at 150 mg 2 times daily, equivalence was demonstrated for peak plasma concentration and area under the curve for bupropion and the three metabolites. Bupropion hydrochloride extended-release tablets (SR) can be taken with or without food. Bupropion Cmax and AUC were increased by 11% to 35% and 16% to 19%, respectively, when bupropion hydrochloride extended-release tablets (SR) was administered with food to healthy volunteers in three trials. The food effect is not considered clinically significant. Following a single-dose administration of bupropion hydrochloride extended-release tablets (SR) in humans, Cmax of bupropion's metabolite hydroxybupropion occurs approximately 6 hours post-dose and is approximately 10 times the peak level of the parent drug at steady state. The elimination half-life of hydroxybupropion is approximately 20 (±5) hours and its AUC at steady state is about 17 times that of bupropion. The times to peak concentrations for the erythrohydrobupropion and threohydrobupropion metabolites are similar to that of the hydroxybupropion metabolite. However, their elimination half-lives are longer, 33(±10) and 37 (±13) hours, respectively, and steady-state AUCs are 1.5 and 7 times that of bupropion, respectively. •Absorption (Drug B): No absorption available •Volume of distribution (Drug A): No volume of distribution available •Volume of distribution (Drug B): No volume of distribution available •Protein binding (Drug A): In vitro tests show that bupropion is 84% bound to human plasma proteins at concentrations up to 200 mcg per mL. The extent of protein binding of the hydroxybupropion metabolite is similar to that for bupropion, whereas the extent of protein binding of the threohydrobupropion metabolite is about half that seen with bupropion. •Protein binding (Drug B): No protein binding available •Metabolism (Drug A): Bupropion is extensively metabolized in humans. Three metabolites are active: hydroxybupropion, which is formed via hydroxylation of the tert-butyl group of bupropion, and the amino-alcohol isomers, threohydrobupropion and erythrohydrobupropion, which are formed via reduction of the carbonyl group. In vitro findings suggest that CYP2B6 is the principal isoenzyme involved in the formation of hydroxybupropion, while cytochrome P450 enzymes are not involved in the formation of threohydrobupropion. Hydroxybupropion has been shown to have the same affinity as bupropion for the norepinephrine transporter (NET) but approximately 50% of its antidepressant activity despite reaching concentrations of ~10-fold higher than that of the parent drug. Oxidation of the bupropion side chain results in the formation of a glycine conjugate of meta-chlorobenzoic acid, which is then excreted as the major urinary metabolite. The potency and toxicity of the metabolites relative to bupropion have not been fully characterized. However, it has been demonstrated in an antidepressant screening test in mice that hydroxybupropion is one-half as potent as bupropion, while threohydrobupropion and erythrohydrobupropion are 5-fold less potent than bupropion. This may be of clinical importance because the plasma concentrations of the metabolites are as high as or higher than those of bupropion. Bupropion and its metabolites exhibit linear kinetics following chronic administration of 300 to 450 mg per day. •Metabolism (Drug B): No metabolism available •Route of elimination (Drug A): Bupropion is extensively metabolized in humans. Oxidation of the bupropion side chain results in the formation of a glycine conjugate of metachlorobenzoic acid, which is then excreted as the major urinary metabolite. Following oral administration of 200 mg of 14C-bupropion in humans, 87% and 10% of the radioactive dose were recovered in the urine and feces, respectively. However, the fraction of the oral dose of bupropion excreted unchanged was only 0.5%, a finding consistent with the extensive metabolism of bupropion. •Route of elimination (Drug B): No route of elimination available •Half-life (Drug A): 24 hours •Half-life (Drug B): No half-life available •Clearance (Drug A): No clearance available •Clearance (Drug B): No clearance available •Toxicity (Drug A): Symptoms of overdose include seizures, hallucinations, loss of consciousness, tachycardia, and cardiac arrest. •Toxicity (Drug B): No toxicity available •Brand Names (Drug A): Aplenzin, Auvelity, Budeprion, Contrave, Forfivo, Wellbutrin, Zyban •Brand Names (Drug B): No brand names available •Synonyms (Drug A): No synonyms listed •Synonyms (Drug B): Nicergolin Nicergolina Nicergoline Nicergolinum •Summary (Drug A): Bupropion is a norepinephrine and dopamine reuptake inhibitor used in the treatment of major depressive disorder (MDD), seasonal affective disorder (SAD), and as an aid to smoking cessation. •Summary (Drug B): Nicergoline is an ergot derivative use for the treatment of symptoms associated with cerebrovascular abnormalities. Output: The subject drug is a strong CYP2D6 inhibitor and the affected drug is metabolized by CYP2D6. Concomitant administration may decrease the metabolism of the affected drug, which could increase serum concentrations as well as the risk and severity of adverse effects. The severity of the interaction is major.

Does Bupropion and Niclosamide interact?

•Drug A: Bupropion •Drug B: Niclosamide •Severity: MINOR •Description: The metabolism of Niclosamide can be decreased when combined with Bupropion. •Extended Description: Both of these agents are reported to be metabolized by CYP2C9. Concomitant administration of multiple CYP2C9 substrates can result in competition for the CYP2C9 binding sites and consequently reduced metabolism and increased plasma levels of one or both of the affected drugs. Elevated plasma levels may result in a higher incidence and/or severity of adverse effects. •Indication (Drug A): Bupropion is indicated for the treatment of major depressive disorder (MDD), seasonal affective disorder (SAD), and as an aid to smoking cessation. When used in combination with naltrexone as the marketed product ContraveⓇ, bupropion is indicated as an adjunct to a reduced-calorie diet and increased physical activity for chronic weight management in adults with an initial body mass index (BMI) of: 30 kg/m^2 or greater (obese) or 27 kg/m^2 or greater (overweight) in the presence of at least one weight-related comorbid condition (e.g., hypertension, type 2 diabetes mellitus, or dyslipidemia). Bupropion is also used off-label as a first-line treatment in patients with ADHD and comorbid bipolar disorder when used as an adjunct to mood stabilizers. •Indication (Drug B): For the treatment of tapeworm and intestinal fluke infections: Taenia saginata (Beef Tapeworm), Taenia solium (Pork Tapeworm), Diphyllobothrium latum (Fish Tapeworm), Fasciolopsis buski (large intestinal fluke). Niclosamide is also used as a molluscicide in the control of schistosomiasis. •Pharmacodynamics (Drug A): Bupropion is chemically unrelated to tricyclic, tetracyclic, selective serotonin re-uptake inhibitors, or other known antidepressant agents. Compared to classical tricyclic antidepressants, Bupropion is a relatively weak inhibitor of the neuronal uptake of norepinephrine and dopamine. In addition, Bupropion does not inhibit monoamine oxidase. Bupropion has been found to be essentially inactive at the serotonin transporter (SERT)(IC50 >10 000 nM), however both bupropion and its primary metabolite hydroxybupropion have been found to block the function of cation-selective serotonin type 3A receptors (5-HT3ARs). Bupropion produces dose-related central nervous system (CNS) stimulant effects in animals, as evidenced by increased locomotor activity, increased rates of responding in various schedule-controlled operant behaviour tasks, and, at high doses, induction of mild stereotyped behaviour. Due to these stimulant effects and selective activity at dopamine and norepinephrine receptors, bupropion has been identified as having an abuse potential. Bupropion has a similar structure to the controlled substance Cathinone, and has been identified as having mild amphetamine-like activity, particularly when inhaled or injected. Bupropion is also known to lower the seizure threshold, making any pre-existing seizure conditions a contraindication to its use. This risk is exacerbated when bupropion is combined with other drugs or substances that lower the seizure threshold, such as cocaine, or in clinical situations that would increase the risk of a seizure such as abrupt alcohol or benzodiazepine withdrawal. As norepinephrine has been shown to have anticonvulsant properties, bupropion's inhibitory effects on NET are thought to contribute to its pro-convulsant activity. Bupropion has been shown to increase blood pressure and pose a risk for exacerbation of unmanaged or pre-existing hypertension, however, clinical trials of bupropion in smokers with CVD have not identified an increased incidence of CV events including stroke or heart attack. In clinical trials, the mean increase in systolic blood pressure associated with the use of bupropion was found to be 1.3 mmHg. •Pharmacodynamics (Drug B): Niclosamide is an antihelminth used against tapeworm infections. It may act by the uncoupling of the electron transport chain to ATP synthase. The disturbance of this crucial metabolic pathway prevents creation of adenosine tri-phosphate (ATP), an essential molecule that supplies energy for metabolism. •Mechanism of action (Drug A): Bupropion is a norepinephrine/dopamine-reuptake inhibitor (NDRI) that exerts its pharmacological effects by weakly inhibiting the enzymes involved in the uptake of the neurotransmitters norepinephrine and dopamine from the synaptic cleft, therefore prolonging their duration of action within the neuronal synapse and the downstream effects of these neurotransmitters. More specifically, bupropion binds to the norepinephrine transporter (NET) and the dopamine transporter (DAT). Bupropion was originally classified as an "atypical" antidepressant because it does not exert the same effects as the classical antidepressants such as Monoamine Oxidase Inhibitors (MAOIs), Tricyclic Antidepressants (TCAs), or Selective Serotonin Reuptake Inhibitors (SSRIs). While it has comparable effectiveness to typical first-line options for the treatment of depression such as SSRIs, bupropion is a unique option for the treatment of MDD as it lacks any clinically relevant serotonergic effects, typical of other mood medications, or any effects on histamine or adrenaline receptors. Lack of activity at these receptors results in a more tolerable side effect profile; bupropion is less likely to cause sexual side effects, sedation, or weight gain as compared to SSRIs or TCAs, for example. When used as an aid to smoking cessation, bupropion is thought to confer its anti-craving and anti-withdrawal effects by inhibiting dopamine reuptake, which is thought to be involved in the reward pathways associated with nicotine, and through the antagonism of the nicotinic acetylcholinergic receptor (AChR), thereby blunting the effects of nicotine. Furthermore, the stimulatory effects produced by bupropion in the central nervous system are similar to nicotine's effects, making low doses of bupropion a suitable option as a nicotine substitute. When used in combination with naltrexone in the marketed product ContraveⓇ for chronic weight management, the two components are thought to have effects on areas of the brain involved in the regulation of food intake. This includes the hypothalamus, which is involved in appetite regulation, and the mesolimbic dopamine circuit, which is involved in reward pathways. Studies have shown that the combined activity of bupropion and naltrexone increase the firing rate of hypothalamic pro-opiomelanocortin (POMC) neurons and blockade of opioid receptor-mediated POMC auto-inhibition, which are associated with a reduction in food intake and increased energy expenditure. This combination was also found to reduce food intake when injected directly into the ventral tegmental area of the mesolimbic circuit in mice, which is an area associated with the regulation of reward pathways. •Mechanism of action (Drug B): Niclosamide works by killing tapeworms on contact. Adult worms (but not ova) are rapidly killed, presumably due to uncoupling of oxidative phosphorylation or stimulation of ATPase activity. The killed worms are then passed in the stool or sometimes destroyed in the intestine. Niclosamide may work as a molluscicide by binding to and damaging DNA. •Absorption (Drug A): Bupropion is currently available in 3 distinct, but bioequivalent formulations: immediate release (IR), sustained-release (SR), and extended-release (XL). Immediate Release Formulation In humans, following oral administration of bupropion hydrochloride tablets, peak plasma bupropion concentrations are usually achieved within 2 hours. IR formulations provide a short duration of action and are therefore generally dosed three times per day. Sustained Release Formulation In humans, following oral administration of bupropion hydrochloride sustained-release tablets (SR), peak plasma concentration (Cmax) of bupropion is usually achieved within 3 hours. SR formulations provide a 12-hour extended release of medication and are therefore generally dosed twice per day. Extended Release Formulation Following single oral administration of bupropion hydrochloride extended-release tablets (XL) to healthy volunteers, the median time to peak plasma concentrations for bupropion was approximately 5 hours. The presence of food did not affect the peak concentration or area under the curve of bupropion. XL formulations provide a 24-hour extended release of medication and are therefore generally dosed once per day/ In a trial comparing chronic dosing with bupropion hydrochloride extended-release tablets (SR) 150 mg twice daily to bupropion immediate-release formulation 100 mg 3 times daily, the steady state Cmax for bupropion after bupropion hydrochloride sustained-release tablets (SR) administration was approximately 85% of those achieved after bupropion immediate-release formulation administration. Exposure (AUC) to bupropion was equivalent for both formulations. Bioequivalence was also demonstrated for all three major active metabolites (i.e., hydroxybupropion, threohydrobupropion and erythrohydrobupropion) for both Cmax and AUC. Thus, at steady state, bupropion hydrochloride sustained-release tablets (SR) given twice daily, and the immediate-release formulation of bupropion given 3 times daily, are essentially bioequivalent for both bupropion and the 3 quantitatively important metabolites. Furthermore, in a study comparing 14-day dosing with bupropion hydrochloride extended-release tablets (XL), 300 mg once-daily to the immediate-release formulation of bupropion at 100 mg 3 times daily, equivalence was demonstrated for peak plasma concentration and area under the curve for bupropion and the three metabolites (hydroxybupropion, threohydrobupropion, and erythrohydrobupropion). Additionally, in a study comparing 14-day dosing with bupropion hydrochloride extended-release tablets (XL) 300 mg once daily to the sustained-release formulation of bupropion at 150 mg 2 times daily, equivalence was demonstrated for peak plasma concentration and area under the curve for bupropion and the three metabolites. Bupropion hydrochloride extended-release tablets (SR) can be taken with or without food. Bupropion Cmax and AUC were increased by 11% to 35% and 16% to 19%, respectively, when bupropion hydrochloride extended-release tablets (SR) was administered with food to healthy volunteers in three trials. The food effect is not considered clinically significant. Following a single-dose administration of bupropion hydrochloride extended-release tablets (SR) in humans, Cmax of bupropion's metabolite hydroxybupropion occurs approximately 6 hours post-dose and is approximately 10 times the peak level of the parent drug at steady state. The elimination half-life of hydroxybupropion is approximately 20 (±5) hours and its AUC at steady state is about 17 times that of bupropion. The times to peak concentrations for the erythrohydrobupropion and threohydrobupropion metabolites are similar to that of the hydroxybupropion metabolite. However, their elimination half-lives are longer, 33(±10) and 37 (±13) hours, respectively, and steady-state AUCs are 1.5 and 7 times that of bupropion, respectively. •Absorption (Drug B): Niclosamide appears to be minimally absorbed from the gastrointestinal tract—neither the drug nor its metabolites have been recovered from the blood or urine. •Volume of distribution (Drug A): No volume of distribution available •Volume of distribution (Drug B): No volume of distribution available •Protein binding (Drug A): In vitro tests show that bupropion is 84% bound to human plasma proteins at concentrations up to 200 mcg per mL. The extent of protein binding of the hydroxybupropion metabolite is similar to that for bupropion, whereas the extent of protein binding of the threohydrobupropion metabolite is about half that seen with bupropion. •Protein binding (Drug B): No protein binding available •Metabolism (Drug A): Bupropion is extensively metabolized in humans. Three metabolites are active: hydroxybupropion, which is formed via hydroxylation of the tert-butyl group of bupropion, and the amino-alcohol isomers, threohydrobupropion and erythrohydrobupropion, which are formed via reduction of the carbonyl group. In vitro findings suggest that CYP2B6 is the principal isoenzyme involved in the formation of hydroxybupropion, while cytochrome P450 enzymes are not involved in the formation of threohydrobupropion. Hydroxybupropion has been shown to have the same affinity as bupropion for the norepinephrine transporter (NET) but approximately 50% of its antidepressant activity despite reaching concentrations of ~10-fold higher than that of the parent drug. Oxidation of the bupropion side chain results in the formation of a glycine conjugate of meta-chlorobenzoic acid, which is then excreted as the major urinary metabolite. The potency and toxicity of the metabolites relative to bupropion have not been fully characterized. However, it has been demonstrated in an antidepressant screening test in mice that hydroxybupropion is one-half as potent as bupropion, while threohydrobupropion and erythrohydrobupropion are 5-fold less potent than bupropion. This may be of clinical importance because the plasma concentrations of the metabolites are as high as or higher than those of bupropion. Bupropion and its metabolites exhibit linear kinetics following chronic administration of 300 to 450 mg per day. •Metabolism (Drug B): No metabolism available •Route of elimination (Drug A): Bupropion is extensively metabolized in humans. Oxidation of the bupropion side chain results in the formation of a glycine conjugate of metachlorobenzoic acid, which is then excreted as the major urinary metabolite. Following oral administration of 200 mg of 14C-bupropion in humans, 87% and 10% of the radioactive dose were recovered in the urine and feces, respectively. However, the fraction of the oral dose of bupropion excreted unchanged was only 0.5%, a finding consistent with the extensive metabolism of bupropion. •Route of elimination (Drug B): No route of elimination available •Half-life (Drug A): 24 hours •Half-life (Drug B): No half-life available •Clearance (Drug A): No clearance available •Clearance (Drug B): No clearance available •Toxicity (Drug A): Symptoms of overdose include seizures, hallucinations, loss of consciousness, tachycardia, and cardiac arrest. •Toxicity (Drug B): Infrequent, mild, and transitory adverse events include nausea, vomiting, diarrhea, and abdominal discomfort. •Brand Names (Drug A): Aplenzin, Auvelity, Budeprion, Contrave, Forfivo, Wellbutrin, Zyban •Brand Names (Drug B): No brand names available •Synonyms (Drug A): No synonyms listed •Synonyms (Drug B): No synonyms listed •Summary (Drug A): Bupropion is a norepinephrine and dopamine reuptake inhibitor used in the treatment of major depressive disorder (MDD), seasonal affective disorder (SAD), and as an aid to smoking cessation. •Summary (Drug B): Niclosamide is an anthelmintic indicated in the treatment of beef, pork, fish, and dwarf tapeworm infections in adults and children.

Both of these agents are reported to be metabolized by CYP2C9. Concomitant administration of multiple CYP2C9 substrates can result in competition for the CYP2C9 binding sites and consequently reduced metabolism and increased plasma levels of one or both of the affected drugs. Elevated plasma levels may result in a higher incidence and/or severity of adverse effects. The severity of the interaction is minor.

Question: Does Bupropion and Niclosamide interact? Information: •Drug A: Bupropion •Drug B: Niclosamide •Severity: MINOR •Description: The metabolism of Niclosamide can be decreased when combined with Bupropion. •Extended Description: Both of these agents are reported to be metabolized by CYP2C9. Concomitant administration of multiple CYP2C9 substrates can result in competition for the CYP2C9 binding sites and consequently reduced metabolism and increased plasma levels of one or both of the affected drugs. Elevated plasma levels may result in a higher incidence and/or severity of adverse effects. •Indication (Drug A): Bupropion is indicated for the treatment of major depressive disorder (MDD), seasonal affective disorder (SAD), and as an aid to smoking cessation. When used in combination with naltrexone as the marketed product ContraveⓇ, bupropion is indicated as an adjunct to a reduced-calorie diet and increased physical activity for chronic weight management in adults with an initial body mass index (BMI) of: 30 kg/m^2 or greater (obese) or 27 kg/m^2 or greater (overweight) in the presence of at least one weight-related comorbid condition (e.g., hypertension, type 2 diabetes mellitus, or dyslipidemia). Bupropion is also used off-label as a first-line treatment in patients with ADHD and comorbid bipolar disorder when used as an adjunct to mood stabilizers. •Indication (Drug B): For the treatment of tapeworm and intestinal fluke infections: Taenia saginata (Beef Tapeworm), Taenia solium (Pork Tapeworm), Diphyllobothrium latum (Fish Tapeworm), Fasciolopsis buski (large intestinal fluke). Niclosamide is also used as a molluscicide in the control of schistosomiasis. •Pharmacodynamics (Drug A): Bupropion is chemically unrelated to tricyclic, tetracyclic, selective serotonin re-uptake inhibitors, or other known antidepressant agents. Compared to classical tricyclic antidepressants, Bupropion is a relatively weak inhibitor of the neuronal uptake of norepinephrine and dopamine. In addition, Bupropion does not inhibit monoamine oxidase. Bupropion has been found to be essentially inactive at the serotonin transporter (SERT)(IC50 >10 000 nM), however both bupropion and its primary metabolite hydroxybupropion have been found to block the function of cation-selective serotonin type 3A receptors (5-HT3ARs). Bupropion produces dose-related central nervous system (CNS) stimulant effects in animals, as evidenced by increased locomotor activity, increased rates of responding in various schedule-controlled operant behaviour tasks, and, at high doses, induction of mild stereotyped behaviour. Due to these stimulant effects and selective activity at dopamine and norepinephrine receptors, bupropion has been identified as having an abuse potential. Bupropion has a similar structure to the controlled substance Cathinone, and has been identified as having mild amphetamine-like activity, particularly when inhaled or injected. Bupropion is also known to lower the seizure threshold, making any pre-existing seizure conditions a contraindication to its use. This risk is exacerbated when bupropion is combined with other drugs or substances that lower the seizure threshold, such as cocaine, or in clinical situations that would increase the risk of a seizure such as abrupt alcohol or benzodiazepine withdrawal. As norepinephrine has been shown to have anticonvulsant properties, bupropion's inhibitory effects on NET are thought to contribute to its pro-convulsant activity. Bupropion has been shown to increase blood pressure and pose a risk for exacerbation of unmanaged or pre-existing hypertension, however, clinical trials of bupropion in smokers with CVD have not identified an increased incidence of CV events including stroke or heart attack. In clinical trials, the mean increase in systolic blood pressure associated with the use of bupropion was found to be 1.3 mmHg. •Pharmacodynamics (Drug B): Niclosamide is an antihelminth used against tapeworm infections. It may act by the uncoupling of the electron transport chain to ATP synthase. The disturbance of this crucial metabolic pathway prevents creation of adenosine tri-phosphate (ATP), an essential molecule that supplies energy for metabolism. •Mechanism of action (Drug A): Bupropion is a norepinephrine/dopamine-reuptake inhibitor (NDRI) that exerts its pharmacological effects by weakly inhibiting the enzymes involved in the uptake of the neurotransmitters norepinephrine and dopamine from the synaptic cleft, therefore prolonging their duration of action within the neuronal synapse and the downstream effects of these neurotransmitters. More specifically, bupropion binds to the norepinephrine transporter (NET) and the dopamine transporter (DAT). Bupropion was originally classified as an "atypical" antidepressant because it does not exert the same effects as the classical antidepressants such as Monoamine Oxidase Inhibitors (MAOIs), Tricyclic Antidepressants (TCAs), or Selective Serotonin Reuptake Inhibitors (SSRIs). While it has comparable effectiveness to typical first-line options for the treatment of depression such as SSRIs, bupropion is a unique option for the treatment of MDD as it lacks any clinically relevant serotonergic effects, typical of other mood medications, or any effects on histamine or adrenaline receptors. Lack of activity at these receptors results in a more tolerable side effect profile; bupropion is less likely to cause sexual side effects, sedation, or weight gain as compared to SSRIs or TCAs, for example. When used as an aid to smoking cessation, bupropion is thought to confer its anti-craving and anti-withdrawal effects by inhibiting dopamine reuptake, which is thought to be involved in the reward pathways associated with nicotine, and through the antagonism of the nicotinic acetylcholinergic receptor (AChR), thereby blunting the effects of nicotine. Furthermore, the stimulatory effects produced by bupropion in the central nervous system are similar to nicotine's effects, making low doses of bupropion a suitable option as a nicotine substitute. When used in combination with naltrexone in the marketed product ContraveⓇ for chronic weight management, the two components are thought to have effects on areas of the brain involved in the regulation of food intake. This includes the hypothalamus, which is involved in appetite regulation, and the mesolimbic dopamine circuit, which is involved in reward pathways. Studies have shown that the combined activity of bupropion and naltrexone increase the firing rate of hypothalamic pro-opiomelanocortin (POMC) neurons and blockade of opioid receptor-mediated POMC auto-inhibition, which are associated with a reduction in food intake and increased energy expenditure. This combination was also found to reduce food intake when injected directly into the ventral tegmental area of the mesolimbic circuit in mice, which is an area associated with the regulation of reward pathways. •Mechanism of action (Drug B): Niclosamide works by killing tapeworms on contact. Adult worms (but not ova) are rapidly killed, presumably due to uncoupling of oxidative phosphorylation or stimulation of ATPase activity. The killed worms are then passed in the stool or sometimes destroyed in the intestine. Niclosamide may work as a molluscicide by binding to and damaging DNA. •Absorption (Drug A): Bupropion is currently available in 3 distinct, but bioequivalent formulations: immediate release (IR), sustained-release (SR), and extended-release (XL). Immediate Release Formulation In humans, following oral administration of bupropion hydrochloride tablets, peak plasma bupropion concentrations are usually achieved within 2 hours. IR formulations provide a short duration of action and are therefore generally dosed three times per day. Sustained Release Formulation In humans, following oral administration of bupropion hydrochloride sustained-release tablets (SR), peak plasma concentration (Cmax) of bupropion is usually achieved within 3 hours. SR formulations provide a 12-hour extended release of medication and are therefore generally dosed twice per day. Extended Release Formulation Following single oral administration of bupropion hydrochloride extended-release tablets (XL) to healthy volunteers, the median time to peak plasma concentrations for bupropion was approximately 5 hours. The presence of food did not affect the peak concentration or area under the curve of bupropion. XL formulations provide a 24-hour extended release of medication and are therefore generally dosed once per day/ In a trial comparing chronic dosing with bupropion hydrochloride extended-release tablets (SR) 150 mg twice daily to bupropion immediate-release formulation 100 mg 3 times daily, the steady state Cmax for bupropion after bupropion hydrochloride sustained-release tablets (SR) administration was approximately 85% of those achieved after bupropion immediate-release formulation administration. Exposure (AUC) to bupropion was equivalent for both formulations. Bioequivalence was also demonstrated for all three major active metabolites (i.e., hydroxybupropion, threohydrobupropion and erythrohydrobupropion) for both Cmax and AUC. Thus, at steady state, bupropion hydrochloride sustained-release tablets (SR) given twice daily, and the immediate-release formulation of bupropion given 3 times daily, are essentially bioequivalent for both bupropion and the 3 quantitatively important metabolites. Furthermore, in a study comparing 14-day dosing with bupropion hydrochloride extended-release tablets (XL), 300 mg once-daily to the immediate-release formulation of bupropion at 100 mg 3 times daily, equivalence was demonstrated for peak plasma concentration and area under the curve for bupropion and the three metabolites (hydroxybupropion, threohydrobupropion, and erythrohydrobupropion). Additionally, in a study comparing 14-day dosing with bupropion hydrochloride extended-release tablets (XL) 300 mg once daily to the sustained-release formulation of bupropion at 150 mg 2 times daily, equivalence was demonstrated for peak plasma concentration and area under the curve for bupropion and the three metabolites. Bupropion hydrochloride extended-release tablets (SR) can be taken with or without food. Bupropion Cmax and AUC were increased by 11% to 35% and 16% to 19%, respectively, when bupropion hydrochloride extended-release tablets (SR) was administered with food to healthy volunteers in three trials. The food effect is not considered clinically significant. Following a single-dose administration of bupropion hydrochloride extended-release tablets (SR) in humans, Cmax of bupropion's metabolite hydroxybupropion occurs approximately 6 hours post-dose and is approximately 10 times the peak level of the parent drug at steady state. The elimination half-life of hydroxybupropion is approximately 20 (±5) hours and its AUC at steady state is about 17 times that of bupropion. The times to peak concentrations for the erythrohydrobupropion and threohydrobupropion metabolites are similar to that of the hydroxybupropion metabolite. However, their elimination half-lives are longer, 33(±10) and 37 (±13) hours, respectively, and steady-state AUCs are 1.5 and 7 times that of bupropion, respectively. •Absorption (Drug B): Niclosamide appears to be minimally absorbed from the gastrointestinal tract—neither the drug nor its metabolites have been recovered from the blood or urine. •Volume of distribution (Drug A): No volume of distribution available •Volume of distribution (Drug B): No volume of distribution available •Protein binding (Drug A): In vitro tests show that bupropion is 84% bound to human plasma proteins at concentrations up to 200 mcg per mL. The extent of protein binding of the hydroxybupropion metabolite is similar to that for bupropion, whereas the extent of protein binding of the threohydrobupropion metabolite is about half that seen with bupropion. •Protein binding (Drug B): No protein binding available •Metabolism (Drug A): Bupropion is extensively metabolized in humans. Three metabolites are active: hydroxybupropion, which is formed via hydroxylation of the tert-butyl group of bupropion, and the amino-alcohol isomers, threohydrobupropion and erythrohydrobupropion, which are formed via reduction of the carbonyl group. In vitro findings suggest that CYP2B6 is the principal isoenzyme involved in the formation of hydroxybupropion, while cytochrome P450 enzymes are not involved in the formation of threohydrobupropion. Hydroxybupropion has been shown to have the same affinity as bupropion for the norepinephrine transporter (NET) but approximately 50% of its antidepressant activity despite reaching concentrations of ~10-fold higher than that of the parent drug. Oxidation of the bupropion side chain results in the formation of a glycine conjugate of meta-chlorobenzoic acid, which is then excreted as the major urinary metabolite. The potency and toxicity of the metabolites relative to bupropion have not been fully characterized. However, it has been demonstrated in an antidepressant screening test in mice that hydroxybupropion is one-half as potent as bupropion, while threohydrobupropion and erythrohydrobupropion are 5-fold less potent than bupropion. This may be of clinical importance because the plasma concentrations of the metabolites are as high as or higher than those of bupropion. Bupropion and its metabolites exhibit linear kinetics following chronic administration of 300 to 450 mg per day. •Metabolism (Drug B): No metabolism available •Route of elimination (Drug A): Bupropion is extensively metabolized in humans. Oxidation of the bupropion side chain results in the formation of a glycine conjugate of metachlorobenzoic acid, which is then excreted as the major urinary metabolite. Following oral administration of 200 mg of 14C-bupropion in humans, 87% and 10% of the radioactive dose were recovered in the urine and feces, respectively. However, the fraction of the oral dose of bupropion excreted unchanged was only 0.5%, a finding consistent with the extensive metabolism of bupropion. •Route of elimination (Drug B): No route of elimination available •Half-life (Drug A): 24 hours •Half-life (Drug B): No half-life available •Clearance (Drug A): No clearance available •Clearance (Drug B): No clearance available •Toxicity (Drug A): Symptoms of overdose include seizures, hallucinations, loss of consciousness, tachycardia, and cardiac arrest. •Toxicity (Drug B): Infrequent, mild, and transitory adverse events include nausea, vomiting, diarrhea, and abdominal discomfort. •Brand Names (Drug A): Aplenzin, Auvelity, Budeprion, Contrave, Forfivo, Wellbutrin, Zyban •Brand Names (Drug B): No brand names available •Synonyms (Drug A): No synonyms listed •Synonyms (Drug B): No synonyms listed •Summary (Drug A): Bupropion is a norepinephrine and dopamine reuptake inhibitor used in the treatment of major depressive disorder (MDD), seasonal affective disorder (SAD), and as an aid to smoking cessation. •Summary (Drug B): Niclosamide is an anthelmintic indicated in the treatment of beef, pork, fish, and dwarf tapeworm infections in adults and children. Output: Both of these agents are reported to be metabolized by CYP2C9. Concomitant administration of multiple CYP2C9 substrates can result in competition for the CYP2C9 binding sites and consequently reduced metabolism and increased plasma levels of one or both of the affected drugs. Elevated plasma levels may result in a higher incidence and/or severity of adverse effects. The severity of the interaction is minor.

Does Bupropion and Nicorandil interact?

•Drug A: Bupropion •Drug B: Nicorandil •Severity: MINOR •Description: Bupropion may decrease the excretion rate of Nicorandil which could result in a higher serum level. •Extended Description: The renal excretion of drugs is the overall result of a combination of kidney processes that include glomerular filtration, passive diffusion, tubular secretion, and tubular reabsorption. Since two of these mechanisms - tubular secretion and reabsorption - are saturable processes , they are consequently susceptible to competition between multiple substrates excreted by the kidneys. If two or more medications that are mainly renally excreted are co-administered, they may compete for renal elimination; there is a large likelihood that one agent may "out-compete" or saturate the renal excretion mechanisms before the other concomitantly administered agent(s) are excreted. As a result, the elimination of these other concurrently administered agents may be inhibited or otherwise delayed, which could lead to increases in their serum concentrations and the risk, incidence, and/or severity of adverse effects associated with the exposure to such drugs. •Indication (Drug A): Bupropion is indicated for the treatment of major depressive disorder (MDD), seasonal affective disorder (SAD), and as an aid to smoking cessation. When used in combination with naltrexone as the marketed product ContraveⓇ, bupropion is indicated as an adjunct to a reduced-calorie diet and increased physical activity for chronic weight management in adults with an initial body mass index (BMI) of: 30 kg/m^2 or greater (obese) or 27 kg/m^2 or greater (overweight) in the presence of at least one weight-related comorbid condition (e.g., hypertension, type 2 diabetes mellitus, or dyslipidemia). Bupropion is also used off-label as a first-line treatment in patients with ADHD and comorbid bipolar disorder when used as an adjunct to mood stabilizers. •Indication (Drug B): Indicated for the prevention and treatment of chronic stable angina pectoris and reduction in the risk of acute coronary syndromes. •Pharmacodynamics (Drug A): Bupropion is chemically unrelated to tricyclic, tetracyclic, selective serotonin re-uptake inhibitors, or other known antidepressant agents. Compared to classical tricyclic antidepressants, Bupropion is a relatively weak inhibitor of the neuronal uptake of norepinephrine and dopamine. In addition, Bupropion does not inhibit monoamine oxidase. Bupropion has been found to be essentially inactive at the serotonin transporter (SERT)(IC50 >10 000 nM), however both bupropion and its primary metabolite hydroxybupropion have been found to block the function of cation-selective serotonin type 3A receptors (5-HT3ARs). Bupropion produces dose-related central nervous system (CNS) stimulant effects in animals, as evidenced by increased locomotor activity, increased rates of responding in various schedule-controlled operant behaviour tasks, and, at high doses, induction of mild stereotyped behaviour. Due to these stimulant effects and selective activity at dopamine and norepinephrine receptors, bupropion has been identified as having an abuse potential. Bupropion has a similar structure to the controlled substance Cathinone, and has been identified as having mild amphetamine-like activity, particularly when inhaled or injected. Bupropion is also known to lower the seizure threshold, making any pre-existing seizure conditions a contraindication to its use. This risk is exacerbated when bupropion is combined with other drugs or substances that lower the seizure threshold, such as cocaine, or in clinical situations that would increase the risk of a seizure such as abrupt alcohol or benzodiazepine withdrawal. As norepinephrine has been shown to have anticonvulsant properties, bupropion's inhibitory effects on NET are thought to contribute to its pro-convulsant activity. Bupropion has been shown to increase blood pressure and pose a risk for exacerbation of unmanaged or pre-existing hypertension, however, clinical trials of bupropion in smokers with CVD have not identified an increased incidence of CV events including stroke or heart attack. In clinical trials, the mean increase in systolic blood pressure associated with the use of bupropion was found to be 1.3 mmHg. •Pharmacodynamics (Drug B): Nicorandil is a potassium channel opener with nitrovasodilator (NO donor) actions, making it both an arterial and a venous dilator. It causes sustained dilation of both the arterial resistance and conductive vessels that increases coronary blood flow, however the effect of the drug on coronary arteries does not involve the coronary steal phenomenon. Activation of potassium channels lead to hyperpolarization of the smooth muscle cells, followed by arterial dilation and afterload reduction. Nicorandil is shown to increase pooling in the capacitance vessels with a decrease in preload through relaxing the venous vascular system. Overall, improved blood flow and reduced infarct size are achieved through reduction of end-diastolix pressure and decreased extravascular component of vascular resistance. Open studies showed the effectiveness of nicorandil treatment on various types of angina pectoris. •Mechanism of action (Drug A): Bupropion is a norepinephrine/dopamine-reuptake inhibitor (NDRI) that exerts its pharmacological effects by weakly inhibiting the enzymes involved in the uptake of the neurotransmitters norepinephrine and dopamine from the synaptic cleft, therefore prolonging their duration of action within the neuronal synapse and the downstream effects of these neurotransmitters. More specifically, bupropion binds to the norepinephrine transporter (NET) and the dopamine transporter (DAT). Bupropion was originally classified as an "atypical" antidepressant because it does not exert the same effects as the classical antidepressants such as Monoamine Oxidase Inhibitors (MAOIs), Tricyclic Antidepressants (TCAs), or Selective Serotonin Reuptake Inhibitors (SSRIs). While it has comparable effectiveness to typical first-line options for the treatment of depression such as SSRIs, bupropion is a unique option for the treatment of MDD as it lacks any clinically relevant serotonergic effects, typical of other mood medications, or any effects on histamine or adrenaline receptors. Lack of activity at these receptors results in a more tolerable side effect profile; bupropion is less likely to cause sexual side effects, sedation, or weight gain as compared to SSRIs or TCAs, for example. When used as an aid to smoking cessation, bupropion is thought to confer its anti-craving and anti-withdrawal effects by inhibiting dopamine reuptake, which is thought to be involved in the reward pathways associated with nicotine, and through the antagonism of the nicotinic acetylcholinergic receptor (AChR), thereby blunting the effects of nicotine. Furthermore, the stimulatory effects produced by bupropion in the central nervous system are similar to nicotine's effects, making low doses of bupropion a suitable option as a nicotine substitute. When used in combination with naltrexone in the marketed product ContraveⓇ for chronic weight management, the two components are thought to have effects on areas of the brain involved in the regulation of food intake. This includes the hypothalamus, which is involved in appetite regulation, and the mesolimbic dopamine circuit, which is involved in reward pathways. Studies have shown that the combined activity of bupropion and naltrexone increase the firing rate of hypothalamic pro-opiomelanocortin (POMC) neurons and blockade of opioid receptor-mediated POMC auto-inhibition, which are associated with a reduction in food intake and increased energy expenditure. This combination was also found to reduce food intake when injected directly into the ventral tegmental area of the mesolimbic circuit in mice, which is an area associated with the regulation of reward pathways. •Mechanism of action (Drug B): Nicorandil mediates its therapeutic efficacy via two main mechanisms. Nicorandil is an activator and opener of ATP-sensitive (ATP-dependent) potassium channels (KATP channels) that are composed of Kir6.x-type subunits and sulfonylurea receptor (SUR) subunits. Nicorandil binding sites are located in the sulfonylurea receptor 2 (SUR2) in the ATP-sensitive potassium channel, which are regulatory subunits of the channel that exhibit an ATPase activitiy. There are 2 types of SUR2 subunits (2A/2B) that have identical nucleotide binding domains (NBD), where SUR2A is more predominantly expressed in skeletal and cardiac myocytes and SUR2B in smooth muscle cells. Nicorandil more potently activates SUR2B/Kir6.2 than SUR2A/Kir6.2 channels to cause hyperpolarization. ATP-NBD1 interaction influences the channel signalling by nicorandil, and the response of the channel to nicorandil is also facilitated and heightened by the interaction of ATP or ADP with NBD2. Potentiated activity of ATP-sensitive channels have cardioprotective role by limiting the duration of action potentials and preventing intraceullar calcium overload. This attenuates cellular injury by preserving cellular energetics and ultimately cell survival. KATP channel-dependent membrane hyperpolarization can also lead to vasodilation via reduction in Ca2+ influx through the voltage-gated Ca2+ channels and regulation of intracellular Ca2+ mobilization in smooth muscle cells. Nicorandil contain a nitrate moiety in its structure, making it a good dilator of vascular smooth muscle like other nitroglycerin esters. Direct relaxation of venous vascular system arises from NO-donor mediated stimulation of guanylyl cyclase and increased levels of intracellular cyclic GMP (cGMP). Elevated levels of cGMP contributes to the total relaxing effect of nicorandil at higher concentrations of the drug. •Absorption (Drug A): Bupropion is currently available in 3 distinct, but bioequivalent formulations: immediate release (IR), sustained-release (SR), and extended-release (XL). Immediate Release Formulation In humans, following oral administration of bupropion hydrochloride tablets, peak plasma bupropion concentrations are usually achieved within 2 hours. IR formulations provide a short duration of action and are therefore generally dosed three times per day. Sustained Release Formulation In humans, following oral administration of bupropion hydrochloride sustained-release tablets (SR), peak plasma concentration (Cmax) of bupropion is usually achieved within 3 hours. SR formulations provide a 12-hour extended release of medication and are therefore generally dosed twice per day. Extended Release Formulation Following single oral administration of bupropion hydrochloride extended-release tablets (XL) to healthy volunteers, the median time to peak plasma concentrations for bupropion was approximately 5 hours. The presence of food did not affect the peak concentration or area under the curve of bupropion. XL formulations provide a 24-hour extended release of medication and are therefore generally dosed once per day/ In a trial comparing chronic dosing with bupropion hydrochloride extended-release tablets (SR) 150 mg twice daily to bupropion immediate-release formulation 100 mg 3 times daily, the steady state Cmax for bupropion after bupropion hydrochloride sustained-release tablets (SR) administration was approximately 85% of those achieved after bupropion immediate-release formulation administration. Exposure (AUC) to bupropion was equivalent for both formulations. Bioequivalence was also demonstrated for all three major active metabolites (i.e., hydroxybupropion, threohydrobupropion and erythrohydrobupropion) for both Cmax and AUC. Thus, at steady state, bupropion hydrochloride sustained-release tablets (SR) given twice daily, and the immediate-release formulation of bupropion given 3 times daily, are essentially bioequivalent for both bupropion and the 3 quantitatively important metabolites. Furthermore, in a study comparing 14-day dosing with bupropion hydrochloride extended-release tablets (XL), 300 mg once-daily to the immediate-release formulation of bupropion at 100 mg 3 times daily, equivalence was demonstrated for peak plasma concentration and area under the curve for bupropion and the three metabolites (hydroxybupropion, threohydrobupropion, and erythrohydrobupropion). Additionally, in a study comparing 14-day dosing with bupropion hydrochloride extended-release tablets (XL) 300 mg once daily to the sustained-release formulation of bupropion at 150 mg 2 times daily, equivalence was demonstrated for peak plasma concentration and area under the curve for bupropion and the three metabolites. Bupropion hydrochloride extended-release tablets (SR) can be taken with or without food. Bupropion Cmax and AUC were increased by 11% to 35% and 16% to 19%, respectively, when bupropion hydrochloride extended-release tablets (SR) was administered with food to healthy volunteers in three trials. The food effect is not considered clinically significant. Following a single-dose administration of bupropion hydrochloride extended-release tablets (SR) in humans, Cmax of bupropion's metabolite hydroxybupropion occurs approximately 6 hours post-dose and is approximately 10 times the peak level of the parent drug at steady state. The elimination half-life of hydroxybupropion is approximately 20 (±5) hours and its AUC at steady state is about 17 times that of bupropion. The times to peak concentrations for the erythrohydrobupropion and threohydrobupropion metabolites are similar to that of the hydroxybupropion metabolite. However, their elimination half-lives are longer, 33(±10) and 37 (±13) hours, respectively, and steady-state AUCs are 1.5 and 7 times that of bupropion, respectively. •Absorption (Drug B): Following oral administration, nicorandil is well absorbed from the gastrointestinal tract with the oral bioavailability of 75% with the maximum peak plasma concentration (Cmax) reached within 30-60 minutes. The mean Cmax is Cmax then is approximately 300 ng/ml. Steady-state plasma concentrations of nicorandil usually are reached within approximately 96-120 h after twice daily dosing (10 or 20mg). •Volume of distribution (Drug A): No volume of distribution available •Volume of distribution (Drug B): After oral (and i.v.) administration of the drug, the apparent volume of distribution is approximately 1.0-1.4 L/kg body weight. •Protein binding (Drug A): In vitro tests show that bupropion is 84% bound to human plasma proteins at concentrations up to 200 mcg per mL. The extent of protein binding of the hydroxybupropion metabolite is similar to that for bupropion, whereas the extent of protein binding of the threohydrobupropion metabolite is about half that seen with bupropion. •Protein binding (Drug B): Nicorandil is about 25% bound to human albumin and other plasma proteins. •Metabolism (Drug A): Bupropion is extensively metabolized in humans. Three metabolites are active: hydroxybupropion, which is formed via hydroxylation of the tert-butyl group of bupropion, and the amino-alcohol isomers, threohydrobupropion and erythrohydrobupropion, which are formed via reduction of the carbonyl group. In vitro findings suggest that CYP2B6 is the principal isoenzyme involved in the formation of hydroxybupropion, while cytochrome P450 enzymes are not involved in the formation of threohydrobupropion. Hydroxybupropion has been shown to have the same affinity as bupropion for the norepinephrine transporter (NET) but approximately 50% of its antidepressant activity despite reaching concentrations of ~10-fold higher than that of the parent drug. Oxidation of the bupropion side chain results in the formation of a glycine conjugate of meta-chlorobenzoic acid, which is then excreted as the major urinary metabolite. The potency and toxicity of the metabolites relative to bupropion have not been fully characterized. However, it has been demonstrated in an antidepressant screening test in mice that hydroxybupropion is one-half as potent as bupropion, while threohydrobupropion and erythrohydrobupropion are 5-fold less potent than bupropion. This may be of clinical importance because the plasma concentrations of the metabolites are as high as or higher than those of bupropion. Bupropion and its metabolites exhibit linear kinetics following chronic administration of 300 to 450 mg per day. •Metabolism (Drug B): Nicorandil undergoes extensive hepatic metabolism. The main biotransformation pathways of nicorandil are denitration, followed by subsequent nicotinamide metabolism. The main pharmacologically inactive denitrated metabolite 2-nicotinamidoethanol can be detected in the urine. The derivatives formed from the nicotinamide metabolism of denitrated products are nicotinuric acid, nicotinamide, N-methylnicotinamide and nicotinic acid. •Route of elimination (Drug A): Bupropion is extensively metabolized in humans. Oxidation of the bupropion side chain results in the formation of a glycine conjugate of metachlorobenzoic acid, which is then excreted as the major urinary metabolite. Following oral administration of 200 mg of 14C-bupropion in humans, 87% and 10% of the radioactive dose were recovered in the urine and feces, respectively. However, the fraction of the oral dose of bupropion excreted unchanged was only 0.5%, a finding consistent with the extensive metabolism of bupropion. •Route of elimination (Drug B): The main route of elimination is the kidney with more than 60% of the administered dose was eliminated in the urine 24 hours after dosing. Only approximately 1% of nicorandil is excreted unchanged in the urine, and the remaining compounds are mainly the denitrated metabolite (9%) and its derivatives (e.g. nicotinuric acid 6%, nicotinamide 1%, N-methylnicotinamide < 1% and nicotinic acid < 1%). Less than 2% of administered dose is excreted through the biliary system. •Half-life (Drug A): 24 hours •Half-life (Drug B): The elimination half life is approximately 1 hour. •Clearance (Drug A): No clearance available •Clearance (Drug B): The total body clearance is approximately 1.15 L/min. •Toxicity (Drug A): Symptoms of overdose include seizures, hallucinations, loss of consciousness, tachycardia, and cardiac arrest. •Toxicity (Drug B): Common adverse effects include lethargy, back pain, chest pain, infection, feeling of weakness. In the cardiovascular system, hypotension, increased heart rate in higher doses, palpitations, worsened angina pectoris and vasodilation/flush may be observed. Dyspepsia, nausea, and vomiting may occur as gastrointestinal disorders. Headaches may arise from vasodilation. Other common side effects include myalgia, bronchitis, dyspnoea, and respiratory disorder. Nicorandil does not affect fertility of male or female rats, and shows no potential in carcinogenic, mutagenic or genotoxic studies. Oral LD50 values in mouse, rat and dog are 626 mg/kg, 1220 mg/kg and 62.5 mg/kg, respectively. •Brand Names (Drug A): Aplenzin, Auvelity, Budeprion, Contrave, Forfivo, Wellbutrin, Zyban •Brand Names (Drug B): No brand names available •Synonyms (Drug A): No synonyms listed •Synonyms (Drug B): Nicorandil Nicorandilum •Summary (Drug A): Bupropion is a norepinephrine and dopamine reuptake inhibitor used in the treatment of major depressive disorder (MDD), seasonal affective disorder (SAD), and as an aid to smoking cessation. •Summary (Drug B): Nicorandil is a vasodilatory drug that functions through potassium channels and intracellular cGMP concentrations commonly used to treat angina.

The renal excretion of drugs is the overall result of a combination of kidney processes that include glomerular filtration, passive diffusion, tubular secretion, and tubular reabsorption. Since two of these mechanisms - tubular secretion and reabsorption - are saturable processes , they are consequently susceptible to competition between multiple substrates excreted by the kidneys. If two or more medications that are mainly renally excreted are co-administered, they may compete for renal elimination; there is a large likelihood that one agent may "out-compete" or saturate the renal excretion mechanisms before the other concomitantly administered agent(s) are excreted. As a result, the elimination of these other concurrently administered agents may be inhibited or otherwise delayed, which could lead to increases in their serum concentrations and the risk, incidence, and/or severity of adverse effects associated with the exposure to such drugs. The severity of the interaction is minor.

Question: Does Bupropion and Nicorandil interact? Information: •Drug A: Bupropion •Drug B: Nicorandil •Severity: MINOR •Description: Bupropion may decrease the excretion rate of Nicorandil which could result in a higher serum level. •Extended Description: The renal excretion of drugs is the overall result of a combination of kidney processes that include glomerular filtration, passive diffusion, tubular secretion, and tubular reabsorption. Since two of these mechanisms - tubular secretion and reabsorption - are saturable processes , they are consequently susceptible to competition between multiple substrates excreted by the kidneys. If two or more medications that are mainly renally excreted are co-administered, they may compete for renal elimination; there is a large likelihood that one agent may "out-compete" or saturate the renal excretion mechanisms before the other concomitantly administered agent(s) are excreted. As a result, the elimination of these other concurrently administered agents may be inhibited or otherwise delayed, which could lead to increases in their serum concentrations and the risk, incidence, and/or severity of adverse effects associated with the exposure to such drugs. •Indication (Drug A): Bupropion is indicated for the treatment of major depressive disorder (MDD), seasonal affective disorder (SAD), and as an aid to smoking cessation. When used in combination with naltrexone as the marketed product ContraveⓇ, bupropion is indicated as an adjunct to a reduced-calorie diet and increased physical activity for chronic weight management in adults with an initial body mass index (BMI) of: 30 kg/m^2 or greater (obese) or 27 kg/m^2 or greater (overweight) in the presence of at least one weight-related comorbid condition (e.g., hypertension, type 2 diabetes mellitus, or dyslipidemia). Bupropion is also used off-label as a first-line treatment in patients with ADHD and comorbid bipolar disorder when used as an adjunct to mood stabilizers. •Indication (Drug B): Indicated for the prevention and treatment of chronic stable angina pectoris and reduction in the risk of acute coronary syndromes. •Pharmacodynamics (Drug A): Bupropion is chemically unrelated to tricyclic, tetracyclic, selective serotonin re-uptake inhibitors, or other known antidepressant agents. Compared to classical tricyclic antidepressants, Bupropion is a relatively weak inhibitor of the neuronal uptake of norepinephrine and dopamine. In addition, Bupropion does not inhibit monoamine oxidase. Bupropion has been found to be essentially inactive at the serotonin transporter (SERT)(IC50 >10 000 nM), however both bupropion and its primary metabolite hydroxybupropion have been found to block the function of cation-selective serotonin type 3A receptors (5-HT3ARs). Bupropion produces dose-related central nervous system (CNS) stimulant effects in animals, as evidenced by increased locomotor activity, increased rates of responding in various schedule-controlled operant behaviour tasks, and, at high doses, induction of mild stereotyped behaviour. Due to these stimulant effects and selective activity at dopamine and norepinephrine receptors, bupropion has been identified as having an abuse potential. Bupropion has a similar structure to the controlled substance Cathinone, and has been identified as having mild amphetamine-like activity, particularly when inhaled or injected. Bupropion is also known to lower the seizure threshold, making any pre-existing seizure conditions a contraindication to its use. This risk is exacerbated when bupropion is combined with other drugs or substances that lower the seizure threshold, such as cocaine, or in clinical situations that would increase the risk of a seizure such as abrupt alcohol or benzodiazepine withdrawal. As norepinephrine has been shown to have anticonvulsant properties, bupropion's inhibitory effects on NET are thought to contribute to its pro-convulsant activity. Bupropion has been shown to increase blood pressure and pose a risk for exacerbation of unmanaged or pre-existing hypertension, however, clinical trials of bupropion in smokers with CVD have not identified an increased incidence of CV events including stroke or heart attack. In clinical trials, the mean increase in systolic blood pressure associated with the use of bupropion was found to be 1.3 mmHg. •Pharmacodynamics (Drug B): Nicorandil is a potassium channel opener with nitrovasodilator (NO donor) actions, making it both an arterial and a venous dilator. It causes sustained dilation of both the arterial resistance and conductive vessels that increases coronary blood flow, however the effect of the drug on coronary arteries does not involve the coronary steal phenomenon. Activation of potassium channels lead to hyperpolarization of the smooth muscle cells, followed by arterial dilation and afterload reduction. Nicorandil is shown to increase pooling in the capacitance vessels with a decrease in preload through relaxing the venous vascular system. Overall, improved blood flow and reduced infarct size are achieved through reduction of end-diastolix pressure and decreased extravascular component of vascular resistance. Open studies showed the effectiveness of nicorandil treatment on various types of angina pectoris. •Mechanism of action (Drug A): Bupropion is a norepinephrine/dopamine-reuptake inhibitor (NDRI) that exerts its pharmacological effects by weakly inhibiting the enzymes involved in the uptake of the neurotransmitters norepinephrine and dopamine from the synaptic cleft, therefore prolonging their duration of action within the neuronal synapse and the downstream effects of these neurotransmitters. More specifically, bupropion binds to the norepinephrine transporter (NET) and the dopamine transporter (DAT). Bupropion was originally classified as an "atypical" antidepressant because it does not exert the same effects as the classical antidepressants such as Monoamine Oxidase Inhibitors (MAOIs), Tricyclic Antidepressants (TCAs), or Selective Serotonin Reuptake Inhibitors (SSRIs). While it has comparable effectiveness to typical first-line options for the treatment of depression such as SSRIs, bupropion is a unique option for the treatment of MDD as it lacks any clinically relevant serotonergic effects, typical of other mood medications, or any effects on histamine or adrenaline receptors. Lack of activity at these receptors results in a more tolerable side effect profile; bupropion is less likely to cause sexual side effects, sedation, or weight gain as compared to SSRIs or TCAs, for example. When used as an aid to smoking cessation, bupropion is thought to confer its anti-craving and anti-withdrawal effects by inhibiting dopamine reuptake, which is thought to be involved in the reward pathways associated with nicotine, and through the antagonism of the nicotinic acetylcholinergic receptor (AChR), thereby blunting the effects of nicotine. Furthermore, the stimulatory effects produced by bupropion in the central nervous system are similar to nicotine's effects, making low doses of bupropion a suitable option as a nicotine substitute. When used in combination with naltrexone in the marketed product ContraveⓇ for chronic weight management, the two components are thought to have effects on areas of the brain involved in the regulation of food intake. This includes the hypothalamus, which is involved in appetite regulation, and the mesolimbic dopamine circuit, which is involved in reward pathways. Studies have shown that the combined activity of bupropion and naltrexone increase the firing rate of hypothalamic pro-opiomelanocortin (POMC) neurons and blockade of opioid receptor-mediated POMC auto-inhibition, which are associated with a reduction in food intake and increased energy expenditure. This combination was also found to reduce food intake when injected directly into the ventral tegmental area of the mesolimbic circuit in mice, which is an area associated with the regulation of reward pathways. •Mechanism of action (Drug B): Nicorandil mediates its therapeutic efficacy via two main mechanisms. Nicorandil is an activator and opener of ATP-sensitive (ATP-dependent) potassium channels (KATP channels) that are composed of Kir6.x-type subunits and sulfonylurea receptor (SUR) subunits. Nicorandil binding sites are located in the sulfonylurea receptor 2 (SUR2) in the ATP-sensitive potassium channel, which are regulatory subunits of the channel that exhibit an ATPase activitiy. There are 2 types of SUR2 subunits (2A/2B) that have identical nucleotide binding domains (NBD), where SUR2A is more predominantly expressed in skeletal and cardiac myocytes and SUR2B in smooth muscle cells. Nicorandil more potently activates SUR2B/Kir6.2 than SUR2A/Kir6.2 channels to cause hyperpolarization. ATP-NBD1 interaction influences the channel signalling by nicorandil, and the response of the channel to nicorandil is also facilitated and heightened by the interaction of ATP or ADP with NBD2. Potentiated activity of ATP-sensitive channels have cardioprotective role by limiting the duration of action potentials and preventing intraceullar calcium overload. This attenuates cellular injury by preserving cellular energetics and ultimately cell survival. KATP channel-dependent membrane hyperpolarization can also lead to vasodilation via reduction in Ca2+ influx through the voltage-gated Ca2+ channels and regulation of intracellular Ca2+ mobilization in smooth muscle cells. Nicorandil contain a nitrate moiety in its structure, making it a good dilator of vascular smooth muscle like other nitroglycerin esters. Direct relaxation of venous vascular system arises from NO-donor mediated stimulation of guanylyl cyclase and increased levels of intracellular cyclic GMP (cGMP). Elevated levels of cGMP contributes to the total relaxing effect of nicorandil at higher concentrations of the drug. •Absorption (Drug A): Bupropion is currently available in 3 distinct, but bioequivalent formulations: immediate release (IR), sustained-release (SR), and extended-release (XL). Immediate Release Formulation In humans, following oral administration of bupropion hydrochloride tablets, peak plasma bupropion concentrations are usually achieved within 2 hours. IR formulations provide a short duration of action and are therefore generally dosed three times per day. Sustained Release Formulation In humans, following oral administration of bupropion hydrochloride sustained-release tablets (SR), peak plasma concentration (Cmax) of bupropion is usually achieved within 3 hours. SR formulations provide a 12-hour extended release of medication and are therefore generally dosed twice per day. Extended Release Formulation Following single oral administration of bupropion hydrochloride extended-release tablets (XL) to healthy volunteers, the median time to peak plasma concentrations for bupropion was approximately 5 hours. The presence of food did not affect the peak concentration or area under the curve of bupropion. XL formulations provide a 24-hour extended release of medication and are therefore generally dosed once per day/ In a trial comparing chronic dosing with bupropion hydrochloride extended-release tablets (SR) 150 mg twice daily to bupropion immediate-release formulation 100 mg 3 times daily, the steady state Cmax for bupropion after bupropion hydrochloride sustained-release tablets (SR) administration was approximately 85% of those achieved after bupropion immediate-release formulation administration. Exposure (AUC) to bupropion was equivalent for both formulations. Bioequivalence was also demonstrated for all three major active metabolites (i.e., hydroxybupropion, threohydrobupropion and erythrohydrobupropion) for both Cmax and AUC. Thus, at steady state, bupropion hydrochloride sustained-release tablets (SR) given twice daily, and the immediate-release formulation of bupropion given 3 times daily, are essentially bioequivalent for both bupropion and the 3 quantitatively important metabolites. Furthermore, in a study comparing 14-day dosing with bupropion hydrochloride extended-release tablets (XL), 300 mg once-daily to the immediate-release formulation of bupropion at 100 mg 3 times daily, equivalence was demonstrated for peak plasma concentration and area under the curve for bupropion and the three metabolites (hydroxybupropion, threohydrobupropion, and erythrohydrobupropion). Additionally, in a study comparing 14-day dosing with bupropion hydrochloride extended-release tablets (XL) 300 mg once daily to the sustained-release formulation of bupropion at 150 mg 2 times daily, equivalence was demonstrated for peak plasma concentration and area under the curve for bupropion and the three metabolites. Bupropion hydrochloride extended-release tablets (SR) can be taken with or without food. Bupropion Cmax and AUC were increased by 11% to 35% and 16% to 19%, respectively, when bupropion hydrochloride extended-release tablets (SR) was administered with food to healthy volunteers in three trials. The food effect is not considered clinically significant. Following a single-dose administration of bupropion hydrochloride extended-release tablets (SR) in humans, Cmax of bupropion's metabolite hydroxybupropion occurs approximately 6 hours post-dose and is approximately 10 times the peak level of the parent drug at steady state. The elimination half-life of hydroxybupropion is approximately 20 (±5) hours and its AUC at steady state is about 17 times that of bupropion. The times to peak concentrations for the erythrohydrobupropion and threohydrobupropion metabolites are similar to that of the hydroxybupropion metabolite. However, their elimination half-lives are longer, 33(±10) and 37 (±13) hours, respectively, and steady-state AUCs are 1.5 and 7 times that of bupropion, respectively. •Absorption (Drug B): Following oral administration, nicorandil is well absorbed from the gastrointestinal tract with the oral bioavailability of 75% with the maximum peak plasma concentration (Cmax) reached within 30-60 minutes. The mean Cmax is Cmax then is approximately 300 ng/ml. Steady-state plasma concentrations of nicorandil usually are reached within approximately 96-120 h after twice daily dosing (10 or 20mg). •Volume of distribution (Drug A): No volume of distribution available •Volume of distribution (Drug B): After oral (and i.v.) administration of the drug, the apparent volume of distribution is approximately 1.0-1.4 L/kg body weight. •Protein binding (Drug A): In vitro tests show that bupropion is 84% bound to human plasma proteins at concentrations up to 200 mcg per mL. The extent of protein binding of the hydroxybupropion metabolite is similar to that for bupropion, whereas the extent of protein binding of the threohydrobupropion metabolite is about half that seen with bupropion. •Protein binding (Drug B): Nicorandil is about 25% bound to human albumin and other plasma proteins. •Metabolism (Drug A): Bupropion is extensively metabolized in humans. Three metabolites are active: hydroxybupropion, which is formed via hydroxylation of the tert-butyl group of bupropion, and the amino-alcohol isomers, threohydrobupropion and erythrohydrobupropion, which are formed via reduction of the carbonyl group. In vitro findings suggest that CYP2B6 is the principal isoenzyme involved in the formation of hydroxybupropion, while cytochrome P450 enzymes are not involved in the formation of threohydrobupropion. Hydroxybupropion has been shown to have the same affinity as bupropion for the norepinephrine transporter (NET) but approximately 50% of its antidepressant activity despite reaching concentrations of ~10-fold higher than that of the parent drug. Oxidation of the bupropion side chain results in the formation of a glycine conjugate of meta-chlorobenzoic acid, which is then excreted as the major urinary metabolite. The potency and toxicity of the metabolites relative to bupropion have not been fully characterized. However, it has been demonstrated in an antidepressant screening test in mice that hydroxybupropion is one-half as potent as bupropion, while threohydrobupropion and erythrohydrobupropion are 5-fold less potent than bupropion. This may be of clinical importance because the plasma concentrations of the metabolites are as high as or higher than those of bupropion. Bupropion and its metabolites exhibit linear kinetics following chronic administration of 300 to 450 mg per day. •Metabolism (Drug B): Nicorandil undergoes extensive hepatic metabolism. The main biotransformation pathways of nicorandil are denitration, followed by subsequent nicotinamide metabolism. The main pharmacologically inactive denitrated metabolite 2-nicotinamidoethanol can be detected in the urine. The derivatives formed from the nicotinamide metabolism of denitrated products are nicotinuric acid, nicotinamide, N-methylnicotinamide and nicotinic acid. •Route of elimination (Drug A): Bupropion is extensively metabolized in humans. Oxidation of the bupropion side chain results in the formation of a glycine conjugate of metachlorobenzoic acid, which is then excreted as the major urinary metabolite. Following oral administration of 200 mg of 14C-bupropion in humans, 87% and 10% of the radioactive dose were recovered in the urine and feces, respectively. However, the fraction of the oral dose of bupropion excreted unchanged was only 0.5%, a finding consistent with the extensive metabolism of bupropion. •Route of elimination (Drug B): The main route of elimination is the kidney with more than 60% of the administered dose was eliminated in the urine 24 hours after dosing. Only approximately 1% of nicorandil is excreted unchanged in the urine, and the remaining compounds are mainly the denitrated metabolite (9%) and its derivatives (e.g. nicotinuric acid 6%, nicotinamide 1%, N-methylnicotinamide < 1% and nicotinic acid < 1%). Less than 2% of administered dose is excreted through the biliary system. •Half-life (Drug A): 24 hours •Half-life (Drug B): The elimination half life is approximately 1 hour. •Clearance (Drug A): No clearance available •Clearance (Drug B): The total body clearance is approximately 1.15 L/min. •Toxicity (Drug A): Symptoms of overdose include seizures, hallucinations, loss of consciousness, tachycardia, and cardiac arrest. •Toxicity (Drug B): Common adverse effects include lethargy, back pain, chest pain, infection, feeling of weakness. In the cardiovascular system, hypotension, increased heart rate in higher doses, palpitations, worsened angina pectoris and vasodilation/flush may be observed. Dyspepsia, nausea, and vomiting may occur as gastrointestinal disorders. Headaches may arise from vasodilation. Other common side effects include myalgia, bronchitis, dyspnoea, and respiratory disorder. Nicorandil does not affect fertility of male or female rats, and shows no potential in carcinogenic, mutagenic or genotoxic studies. Oral LD50 values in mouse, rat and dog are 626 mg/kg, 1220 mg/kg and 62.5 mg/kg, respectively. •Brand Names (Drug A): Aplenzin, Auvelity, Budeprion, Contrave, Forfivo, Wellbutrin, Zyban •Brand Names (Drug B): No brand names available •Synonyms (Drug A): No synonyms listed •Synonyms (Drug B): Nicorandil Nicorandilum •Summary (Drug A): Bupropion is a norepinephrine and dopamine reuptake inhibitor used in the treatment of major depressive disorder (MDD), seasonal affective disorder (SAD), and as an aid to smoking cessation. •Summary (Drug B): Nicorandil is a vasodilatory drug that functions through potassium channels and intracellular cGMP concentrations commonly used to treat angina. Output: The renal excretion of drugs is the overall result of a combination of kidney processes that include glomerular filtration, passive diffusion, tubular secretion, and tubular reabsorption. Since two of these mechanisms - tubular secretion and reabsorption - are saturable processes , they are consequently susceptible to competition between multiple substrates excreted by the kidneys. If two or more medications that are mainly renally excreted are co-administered, they may compete for renal elimination; there is a large likelihood that one agent may "out-compete" or saturate the renal excretion mechanisms before the other concomitantly administered agent(s) are excreted. As a result, the elimination of these other concurrently administered agents may be inhibited or otherwise delayed, which could lead to increases in their serum concentrations and the risk, incidence, and/or severity of adverse effects associated with the exposure to such drugs. The severity of the interaction is minor.

Does Bupropion and Nicotine interact?

•Drug A: Bupropion •Drug B: Nicotine •Severity: MODERATE •Description: The metabolism of Bupropion can be decreased when combined with Nicotine. •Extended Description: When a CYP2B6 substrate is coadministered with another CYP2B6 substrate, both substrates will invariably compete with each other to be metabolized by the limited quantities of CYP2B6 isoenzymes present in the body. When one substrate is subsequently capable of 'out-competing' the other, this other substrate will have its CYP2B6 facilitated metabolism stalled or otherwise decreased for a time, resulting in increased serum concentrations of this substrate and/or an increased risk, incidence, or severity of adverse effects associated with exposure to this substrate. •Indication (Drug A): Bupropion is indicated for the treatment of major depressive disorder (MDD), seasonal affective disorder (SAD), and as an aid to smoking cessation. When used in combination with naltrexone as the marketed product ContraveⓇ, bupropion is indicated as an adjunct to a reduced-calorie diet and increased physical activity for chronic weight management in adults with an initial body mass index (BMI) of: 30 kg/m^2 or greater (obese) or 27 kg/m^2 or greater (overweight) in the presence of at least one weight-related comorbid condition (e.g., hypertension, type 2 diabetes mellitus, or dyslipidemia). Bupropion is also used off-label as a first-line treatment in patients with ADHD and comorbid bipolar disorder when used as an adjunct to mood stabilizers. •Indication (Drug B): For the relief of nicotine withdrawal symptoms and as an aid to smoking cessation. •Pharmacodynamics (Drug A): Bupropion is chemically unrelated to tricyclic, tetracyclic, selective serotonin re-uptake inhibitors, or other known antidepressant agents. Compared to classical tricyclic antidepressants, Bupropion is a relatively weak inhibitor of the neuronal uptake of norepinephrine and dopamine. In addition, Bupropion does not inhibit monoamine oxidase. Bupropion has been found to be essentially inactive at the serotonin transporter (SERT)(IC50 >10 000 nM), however both bupropion and its primary metabolite hydroxybupropion have been found to block the function of cation-selective serotonin type 3A receptors (5-HT3ARs). Bupropion produces dose-related central nervous system (CNS) stimulant effects in animals, as evidenced by increased locomotor activity, increased rates of responding in various schedule-controlled operant behaviour tasks, and, at high doses, induction of mild stereotyped behaviour. Due to these stimulant effects and selective activity at dopamine and norepinephrine receptors, bupropion has been identified as having an abuse potential. Bupropion has a similar structure to the controlled substance Cathinone, and has been identified as having mild amphetamine-like activity, particularly when inhaled or injected. Bupropion is also known to lower the seizure threshold, making any pre-existing seizure conditions a contraindication to its use. This risk is exacerbated when bupropion is combined with other drugs or substances that lower the seizure threshold, such as cocaine, or in clinical situations that would increase the risk of a seizure such as abrupt alcohol or benzodiazepine withdrawal. As norepinephrine has been shown to have anticonvulsant properties, bupropion's inhibitory effects on NET are thought to contribute to its pro-convulsant activity. Bupropion has been shown to increase blood pressure and pose a risk for exacerbation of unmanaged or pre-existing hypertension, however, clinical trials of bupropion in smokers with CVD have not identified an increased incidence of CV events including stroke or heart attack. In clinical trials, the mean increase in systolic blood pressure associated with the use of bupropion was found to be 1.3 mmHg. •Pharmacodynamics (Drug B): Nicotine, the primary alkaloid in tobacco products binds stereo-selectively to nicotinic-cholinergic receptors on autonomic ganglia, the adrenal medulla, neuromuscular junctions and in the brain. Nicotine exerts two effects, a stimulant effect exerted at the locus ceruleus and a reward effect in the limbic system. Itranvenous administration of nicotine causes release of acetylcholine, norepinephrine, dopamine, serotonine, vasopressin, beta-endorphin and ACTH. Nicotine is a highly addictive substance. Nicotine also induces peripheral vasoconstriction, tachycardia and elevated blood pressure. Nicotine inhalers and patches are used to treat smoking withdrawl syndrome. Nicotine is classified as a stimulant of autonomic ganglia. •Mechanism of action (Drug A): Bupropion is a norepinephrine/dopamine-reuptake inhibitor (NDRI) that exerts its pharmacological effects by weakly inhibiting the enzymes involved in the uptake of the neurotransmitters norepinephrine and dopamine from the synaptic cleft, therefore prolonging their duration of action within the neuronal synapse and the downstream effects of these neurotransmitters. More specifically, bupropion binds to the norepinephrine transporter (NET) and the dopamine transporter (DAT). Bupropion was originally classified as an "atypical" antidepressant because it does not exert the same effects as the classical antidepressants such as Monoamine Oxidase Inhibitors (MAOIs), Tricyclic Antidepressants (TCAs), or Selective Serotonin Reuptake Inhibitors (SSRIs). While it has comparable effectiveness to typical first-line options for the treatment of depression such as SSRIs, bupropion is a unique option for the treatment of MDD as it lacks any clinically relevant serotonergic effects, typical of other mood medications, or any effects on histamine or adrenaline receptors. Lack of activity at these receptors results in a more tolerable side effect profile; bupropion is less likely to cause sexual side effects, sedation, or weight gain as compared to SSRIs or TCAs, for example. When used as an aid to smoking cessation, bupropion is thought to confer its anti-craving and anti-withdrawal effects by inhibiting dopamine reuptake, which is thought to be involved in the reward pathways associated with nicotine, and through the antagonism of the nicotinic acetylcholinergic receptor (AChR), thereby blunting the effects of nicotine. Furthermore, the stimulatory effects produced by bupropion in the central nervous system are similar to nicotine's effects, making low doses of bupropion a suitable option as a nicotine substitute. When used in combination with naltrexone in the marketed product ContraveⓇ for chronic weight management, the two components are thought to have effects on areas of the brain involved in the regulation of food intake. This includes the hypothalamus, which is involved in appetite regulation, and the mesolimbic dopamine circuit, which is involved in reward pathways. Studies have shown that the combined activity of bupropion and naltrexone increase the firing rate of hypothalamic pro-opiomelanocortin (POMC) neurons and blockade of opioid receptor-mediated POMC auto-inhibition, which are associated with a reduction in food intake and increased energy expenditure. This combination was also found to reduce food intake when injected directly into the ventral tegmental area of the mesolimbic circuit in mice, which is an area associated with the regulation of reward pathways. •Mechanism of action (Drug B): Nicotine is a stimulant drug that acts as an agonist at nicotinic acetylcholine receptors. These are ionotropic receptors composed up of five homomeric or heteromeric subunits. In the brain, nicotine binds to nicotinic acetylcholine receptors on dopaminergic neurons in the cortico-limbic pathways. This causes the channel to open and allow conductance of multiple cations including sodium, calcium, and potassium. This leads to depolarization, which activates voltage-gated calcium channels and allows more calcium to enter the axon terminal. Calcium stimulates vesicle trafficking towards the plasma membrane and the release of dopamine into the synapse. Dopamine binding to its receptors is responsible the euphoric and addictive properties of nicotine. Nicotine also binds to nicotinic acetylcholine receptors on the chromaffin cells in the adrenal medulla. Binding opens the ion channel allowing influx of sodium, causing depolarization of the cell, which activates voltage-gated calcium channels. Calcium triggers the release of epinephrine from intracellular vesicles into the bloodstream, which causes vasoconstriction, increased blood pressure, increased heart rate, and increased blood sugar. •Absorption (Drug A): Bupropion is currently available in 3 distinct, but bioequivalent formulations: immediate release (IR), sustained-release (SR), and extended-release (XL). Immediate Release Formulation In humans, following oral administration of bupropion hydrochloride tablets, peak plasma bupropion concentrations are usually achieved within 2 hours. IR formulations provide a short duration of action and are therefore generally dosed three times per day. Sustained Release Formulation In humans, following oral administration of bupropion hydrochloride sustained-release tablets (SR), peak plasma concentration (Cmax) of bupropion is usually achieved within 3 hours. SR formulations provide a 12-hour extended release of medication and are therefore generally dosed twice per day. Extended Release Formulation Following single oral administration of bupropion hydrochloride extended-release tablets (XL) to healthy volunteers, the median time to peak plasma concentrations for bupropion was approximately 5 hours. The presence of food did not affect the peak concentration or area under the curve of bupropion. XL formulations provide a 24-hour extended release of medication and are therefore generally dosed once per day/ In a trial comparing chronic dosing with bupropion hydrochloride extended-release tablets (SR) 150 mg twice daily to bupropion immediate-release formulation 100 mg 3 times daily, the steady state Cmax for bupropion after bupropion hydrochloride sustained-release tablets (SR) administration was approximately 85% of those achieved after bupropion immediate-release formulation administration. Exposure (AUC) to bupropion was equivalent for both formulations. Bioequivalence was also demonstrated for all three major active metabolites (i.e., hydroxybupropion, threohydrobupropion and erythrohydrobupropion) for both Cmax and AUC. Thus, at steady state, bupropion hydrochloride sustained-release tablets (SR) given twice daily, and the immediate-release formulation of bupropion given 3 times daily, are essentially bioequivalent for both bupropion and the 3 quantitatively important metabolites. Furthermore, in a study comparing 14-day dosing with bupropion hydrochloride extended-release tablets (XL), 300 mg once-daily to the immediate-release formulation of bupropion at 100 mg 3 times daily, equivalence was demonstrated for peak plasma concentration and area under the curve for bupropion and the three metabolites (hydroxybupropion, threohydrobupropion, and erythrohydrobupropion). Additionally, in a study comparing 14-day dosing with bupropion hydrochloride extended-release tablets (XL) 300 mg once daily to the sustained-release formulation of bupropion at 150 mg 2 times daily, equivalence was demonstrated for peak plasma concentration and area under the curve for bupropion and the three metabolites. Bupropion hydrochloride extended-release tablets (SR) can be taken with or without food. Bupropion Cmax and AUC were increased by 11% to 35% and 16% to 19%, respectively, when bupropion hydrochloride extended-release tablets (SR) was administered with food to healthy volunteers in three trials. The food effect is not considered clinically significant. Following a single-dose administration of bupropion hydrochloride extended-release tablets (SR) in humans, Cmax of bupropion's metabolite hydroxybupropion occurs approximately 6 hours post-dose and is approximately 10 times the peak level of the parent drug at steady state. The elimination half-life of hydroxybupropion is approximately 20 (±5) hours and its AUC at steady state is about 17 times that of bupropion. The times to peak concentrations for the erythrohydrobupropion and threohydrobupropion metabolites are similar to that of the hydroxybupropion metabolite. However, their elimination half-lives are longer, 33(±10) and 37 (±13) hours, respectively, and steady-state AUCs are 1.5 and 7 times that of bupropion, respectively. •Absorption (Drug B): Absorption of nicotine through the buccal mucosa is relatively slow and the high and rapid rise followed by the decline in nicotine arterial plasma concentrations seen with cigarette smoking are not achieved with the inhaler. About 10% of absorbed nicotine is excreted unchanged in urine. •Volume of distribution (Drug A): No volume of distribution available •Volume of distribution (Drug B): 2 to 3 L/kg •Protein binding (Drug A): In vitro tests show that bupropion is 84% bound to human plasma proteins at concentrations up to 200 mcg per mL. The extent of protein binding of the hydroxybupropion metabolite is similar to that for bupropion, whereas the extent of protein binding of the threohydrobupropion metabolite is about half that seen with bupropion. •Protein binding (Drug B): Less than 5% •Metabolism (Drug A): Bupropion is extensively metabolized in humans. Three metabolites are active: hydroxybupropion, which is formed via hydroxylation of the tert-butyl group of bupropion, and the amino-alcohol isomers, threohydrobupropion and erythrohydrobupropion, which are formed via reduction of the carbonyl group. In vitro findings suggest that CYP2B6 is the principal isoenzyme involved in the formation of hydroxybupropion, while cytochrome P450 enzymes are not involved in the formation of threohydrobupropion. Hydroxybupropion has been shown to have the same affinity as bupropion for the norepinephrine transporter (NET) but approximately 50% of its antidepressant activity despite reaching concentrations of ~10-fold higher than that of the parent drug. Oxidation of the bupropion side chain results in the formation of a glycine conjugate of meta-chlorobenzoic acid, which is then excreted as the major urinary metabolite. The potency and toxicity of the metabolites relative to bupropion have not been fully characterized. However, it has been demonstrated in an antidepressant screening test in mice that hydroxybupropion is one-half as potent as bupropion, while threohydrobupropion and erythrohydrobupropion are 5-fold less potent than bupropion. This may be of clinical importance because the plasma concentrations of the metabolites are as high as or higher than those of bupropion. Bupropion and its metabolites exhibit linear kinetics following chronic administration of 300 to 450 mg per day. •Metabolism (Drug B): Primarily hepatic, cotinine is the primary metabolite. •Route of elimination (Drug A): Bupropion is extensively metabolized in humans. Oxidation of the bupropion side chain results in the formation of a glycine conjugate of metachlorobenzoic acid, which is then excreted as the major urinary metabolite. Following oral administration of 200 mg of 14C-bupropion in humans, 87% and 10% of the radioactive dose were recovered in the urine and feces, respectively. However, the fraction of the oral dose of bupropion excreted unchanged was only 0.5%, a finding consistent with the extensive metabolism of bupropion. •Route of elimination (Drug B): About 10% of the nicotine absorbed is excreted unchanged in the urine. •Half-life (Drug A): 24 hours •Half-life (Drug B): Cotinine has a half life of 15-20 hours, while nicotine has a half life of 1-3 hours •Clearance (Drug A): No clearance available •Clearance (Drug B): 1.2 L/min [healthy adult smoker] •Toxicity (Drug A): Symptoms of overdose include seizures, hallucinations, loss of consciousness, tachycardia, and cardiac arrest. •Toxicity (Drug B): Symptoms of overdose include nausea, abdominal pain, vomiting, diarrhea, diaphoresis, flushing, dizziness, disturbed hearing and vision, confusion, weakness, palpitations, altered respiration and hypotension. LD 50 = 24 mg/kg (orally in mice). •Brand Names (Drug A): Aplenzin, Auvelity, Budeprion, Contrave, Forfivo, Wellbutrin, Zyban •Brand Names (Drug B): Habitrol, Nicoderm C-Q, Nicorelief, Nicorette, Nicotrol •Synonyms (Drug A): No synonyms listed •Synonyms (Drug B): (S)-Nicotine Nicotina Nicotine Nicotine betadex Nicotine polacrilex Nikotin Nikotyna •Summary (Drug A): Bupropion is a norepinephrine and dopamine reuptake inhibitor used in the treatment of major depressive disorder (MDD), seasonal affective disorder (SAD), and as an aid to smoking cessation. •Summary (Drug B): Nicotine is a stimulatory alkaloid found in tobacco products that is often used for the relief of nicotine withdrawal symptoms and as an aid to smoking cessation.

When a CYP2B6 substrate is coadministered with another CYP2B6 substrate, both substrates will invariably compete with each other to be metabolized by the limited quantities of CYP2B6 isoenzymes present in the body. When one substrate is subsequently capable of 'out-competing' the other, this other substrate will have its CYP2B6 facilitated metabolism stalled or otherwise decreased for a time, resulting in increased serum concentrations of this substrate and/or an increased risk, incidence, or severity of adverse effects associated with exposure to this substrate. The severity of the interaction is moderate.

Question: Does Bupropion and Nicotine interact? Information: •Drug A: Bupropion •Drug B: Nicotine •Severity: MODERATE •Description: The metabolism of Bupropion can be decreased when combined with Nicotine. •Extended Description: When a CYP2B6 substrate is coadministered with another CYP2B6 substrate, both substrates will invariably compete with each other to be metabolized by the limited quantities of CYP2B6 isoenzymes present in the body. When one substrate is subsequently capable of 'out-competing' the other, this other substrate will have its CYP2B6 facilitated metabolism stalled or otherwise decreased for a time, resulting in increased serum concentrations of this substrate and/or an increased risk, incidence, or severity of adverse effects associated with exposure to this substrate. •Indication (Drug A): Bupropion is indicated for the treatment of major depressive disorder (MDD), seasonal affective disorder (SAD), and as an aid to smoking cessation. When used in combination with naltrexone as the marketed product ContraveⓇ, bupropion is indicated as an adjunct to a reduced-calorie diet and increased physical activity for chronic weight management in adults with an initial body mass index (BMI) of: 30 kg/m^2 or greater (obese) or 27 kg/m^2 or greater (overweight) in the presence of at least one weight-related comorbid condition (e.g., hypertension, type 2 diabetes mellitus, or dyslipidemia). Bupropion is also used off-label as a first-line treatment in patients with ADHD and comorbid bipolar disorder when used as an adjunct to mood stabilizers. •Indication (Drug B): For the relief of nicotine withdrawal symptoms and as an aid to smoking cessation. •Pharmacodynamics (Drug A): Bupropion is chemically unrelated to tricyclic, tetracyclic, selective serotonin re-uptake inhibitors, or other known antidepressant agents. Compared to classical tricyclic antidepressants, Bupropion is a relatively weak inhibitor of the neuronal uptake of norepinephrine and dopamine. In addition, Bupropion does not inhibit monoamine oxidase. Bupropion has been found to be essentially inactive at the serotonin transporter (SERT)(IC50 >10 000 nM), however both bupropion and its primary metabolite hydroxybupropion have been found to block the function of cation-selective serotonin type 3A receptors (5-HT3ARs). Bupropion produces dose-related central nervous system (CNS) stimulant effects in animals, as evidenced by increased locomotor activity, increased rates of responding in various schedule-controlled operant behaviour tasks, and, at high doses, induction of mild stereotyped behaviour. Due to these stimulant effects and selective activity at dopamine and norepinephrine receptors, bupropion has been identified as having an abuse potential. Bupropion has a similar structure to the controlled substance Cathinone, and has been identified as having mild amphetamine-like activity, particularly when inhaled or injected. Bupropion is also known to lower the seizure threshold, making any pre-existing seizure conditions a contraindication to its use. This risk is exacerbated when bupropion is combined with other drugs or substances that lower the seizure threshold, such as cocaine, or in clinical situations that would increase the risk of a seizure such as abrupt alcohol or benzodiazepine withdrawal. As norepinephrine has been shown to have anticonvulsant properties, bupropion's inhibitory effects on NET are thought to contribute to its pro-convulsant activity. Bupropion has been shown to increase blood pressure and pose a risk for exacerbation of unmanaged or pre-existing hypertension, however, clinical trials of bupropion in smokers with CVD have not identified an increased incidence of CV events including stroke or heart attack. In clinical trials, the mean increase in systolic blood pressure associated with the use of bupropion was found to be 1.3 mmHg. •Pharmacodynamics (Drug B): Nicotine, the primary alkaloid in tobacco products binds stereo-selectively to nicotinic-cholinergic receptors on autonomic ganglia, the adrenal medulla, neuromuscular junctions and in the brain. Nicotine exerts two effects, a stimulant effect exerted at the locus ceruleus and a reward effect in the limbic system. Itranvenous administration of nicotine causes release of acetylcholine, norepinephrine, dopamine, serotonine, vasopressin, beta-endorphin and ACTH. Nicotine is a highly addictive substance. Nicotine also induces peripheral vasoconstriction, tachycardia and elevated blood pressure. Nicotine inhalers and patches are used to treat smoking withdrawl syndrome. Nicotine is classified as a stimulant of autonomic ganglia. •Mechanism of action (Drug A): Bupropion is a norepinephrine/dopamine-reuptake inhibitor (NDRI) that exerts its pharmacological effects by weakly inhibiting the enzymes involved in the uptake of the neurotransmitters norepinephrine and dopamine from the synaptic cleft, therefore prolonging their duration of action within the neuronal synapse and the downstream effects of these neurotransmitters. More specifically, bupropion binds to the norepinephrine transporter (NET) and the dopamine transporter (DAT). Bupropion was originally classified as an "atypical" antidepressant because it does not exert the same effects as the classical antidepressants such as Monoamine Oxidase Inhibitors (MAOIs), Tricyclic Antidepressants (TCAs), or Selective Serotonin Reuptake Inhibitors (SSRIs). While it has comparable effectiveness to typical first-line options for the treatment of depression such as SSRIs, bupropion is a unique option for the treatment of MDD as it lacks any clinically relevant serotonergic effects, typical of other mood medications, or any effects on histamine or adrenaline receptors. Lack of activity at these receptors results in a more tolerable side effect profile; bupropion is less likely to cause sexual side effects, sedation, or weight gain as compared to SSRIs or TCAs, for example. When used as an aid to smoking cessation, bupropion is thought to confer its anti-craving and anti-withdrawal effects by inhibiting dopamine reuptake, which is thought to be involved in the reward pathways associated with nicotine, and through the antagonism of the nicotinic acetylcholinergic receptor (AChR), thereby blunting the effects of nicotine. Furthermore, the stimulatory effects produced by bupropion in the central nervous system are similar to nicotine's effects, making low doses of bupropion a suitable option as a nicotine substitute. When used in combination with naltrexone in the marketed product ContraveⓇ for chronic weight management, the two components are thought to have effects on areas of the brain involved in the regulation of food intake. This includes the hypothalamus, which is involved in appetite regulation, and the mesolimbic dopamine circuit, which is involved in reward pathways. Studies have shown that the combined activity of bupropion and naltrexone increase the firing rate of hypothalamic pro-opiomelanocortin (POMC) neurons and blockade of opioid receptor-mediated POMC auto-inhibition, which are associated with a reduction in food intake and increased energy expenditure. This combination was also found to reduce food intake when injected directly into the ventral tegmental area of the mesolimbic circuit in mice, which is an area associated with the regulation of reward pathways. •Mechanism of action (Drug B): Nicotine is a stimulant drug that acts as an agonist at nicotinic acetylcholine receptors. These are ionotropic receptors composed up of five homomeric or heteromeric subunits. In the brain, nicotine binds to nicotinic acetylcholine receptors on dopaminergic neurons in the cortico-limbic pathways. This causes the channel to open and allow conductance of multiple cations including sodium, calcium, and potassium. This leads to depolarization, which activates voltage-gated calcium channels and allows more calcium to enter the axon terminal. Calcium stimulates vesicle trafficking towards the plasma membrane and the release of dopamine into the synapse. Dopamine binding to its receptors is responsible the euphoric and addictive properties of nicotine. Nicotine also binds to nicotinic acetylcholine receptors on the chromaffin cells in the adrenal medulla. Binding opens the ion channel allowing influx of sodium, causing depolarization of the cell, which activates voltage-gated calcium channels. Calcium triggers the release of epinephrine from intracellular vesicles into the bloodstream, which causes vasoconstriction, increased blood pressure, increased heart rate, and increased blood sugar. •Absorption (Drug A): Bupropion is currently available in 3 distinct, but bioequivalent formulations: immediate release (IR), sustained-release (SR), and extended-release (XL). Immediate Release Formulation In humans, following oral administration of bupropion hydrochloride tablets, peak plasma bupropion concentrations are usually achieved within 2 hours. IR formulations provide a short duration of action and are therefore generally dosed three times per day. Sustained Release Formulation In humans, following oral administration of bupropion hydrochloride sustained-release tablets (SR), peak plasma concentration (Cmax) of bupropion is usually achieved within 3 hours. SR formulations provide a 12-hour extended release of medication and are therefore generally dosed twice per day. Extended Release Formulation Following single oral administration of bupropion hydrochloride extended-release tablets (XL) to healthy volunteers, the median time to peak plasma concentrations for bupropion was approximately 5 hours. The presence of food did not affect the peak concentration or area under the curve of bupropion. XL formulations provide a 24-hour extended release of medication and are therefore generally dosed once per day/ In a trial comparing chronic dosing with bupropion hydrochloride extended-release tablets (SR) 150 mg twice daily to bupropion immediate-release formulation 100 mg 3 times daily, the steady state Cmax for bupropion after bupropion hydrochloride sustained-release tablets (SR) administration was approximately 85% of those achieved after bupropion immediate-release formulation administration. Exposure (AUC) to bupropion was equivalent for both formulations. Bioequivalence was also demonstrated for all three major active metabolites (i.e., hydroxybupropion, threohydrobupropion and erythrohydrobupropion) for both Cmax and AUC. Thus, at steady state, bupropion hydrochloride sustained-release tablets (SR) given twice daily, and the immediate-release formulation of bupropion given 3 times daily, are essentially bioequivalent for both bupropion and the 3 quantitatively important metabolites. Furthermore, in a study comparing 14-day dosing with bupropion hydrochloride extended-release tablets (XL), 300 mg once-daily to the immediate-release formulation of bupropion at 100 mg 3 times daily, equivalence was demonstrated for peak plasma concentration and area under the curve for bupropion and the three metabolites (hydroxybupropion, threohydrobupropion, and erythrohydrobupropion). Additionally, in a study comparing 14-day dosing with bupropion hydrochloride extended-release tablets (XL) 300 mg once daily to the sustained-release formulation of bupropion at 150 mg 2 times daily, equivalence was demonstrated for peak plasma concentration and area under the curve for bupropion and the three metabolites. Bupropion hydrochloride extended-release tablets (SR) can be taken with or without food. Bupropion Cmax and AUC were increased by 11% to 35% and 16% to 19%, respectively, when bupropion hydrochloride extended-release tablets (SR) was administered with food to healthy volunteers in three trials. The food effect is not considered clinically significant. Following a single-dose administration of bupropion hydrochloride extended-release tablets (SR) in humans, Cmax of bupropion's metabolite hydroxybupropion occurs approximately 6 hours post-dose and is approximately 10 times the peak level of the parent drug at steady state. The elimination half-life of hydroxybupropion is approximately 20 (±5) hours and its AUC at steady state is about 17 times that of bupropion. The times to peak concentrations for the erythrohydrobupropion and threohydrobupropion metabolites are similar to that of the hydroxybupropion metabolite. However, their elimination half-lives are longer, 33(±10) and 37 (±13) hours, respectively, and steady-state AUCs are 1.5 and 7 times that of bupropion, respectively. •Absorption (Drug B): Absorption of nicotine through the buccal mucosa is relatively slow and the high and rapid rise followed by the decline in nicotine arterial plasma concentrations seen with cigarette smoking are not achieved with the inhaler. About 10% of absorbed nicotine is excreted unchanged in urine. •Volume of distribution (Drug A): No volume of distribution available •Volume of distribution (Drug B): 2 to 3 L/kg •Protein binding (Drug A): In vitro tests show that bupropion is 84% bound to human plasma proteins at concentrations up to 200 mcg per mL. The extent of protein binding of the hydroxybupropion metabolite is similar to that for bupropion, whereas the extent of protein binding of the threohydrobupropion metabolite is about half that seen with bupropion. •Protein binding (Drug B): Less than 5% •Metabolism (Drug A): Bupropion is extensively metabolized in humans. Three metabolites are active: hydroxybupropion, which is formed via hydroxylation of the tert-butyl group of bupropion, and the amino-alcohol isomers, threohydrobupropion and erythrohydrobupropion, which are formed via reduction of the carbonyl group. In vitro findings suggest that CYP2B6 is the principal isoenzyme involved in the formation of hydroxybupropion, while cytochrome P450 enzymes are not involved in the formation of threohydrobupropion. Hydroxybupropion has been shown to have the same affinity as bupropion for the norepinephrine transporter (NET) but approximately 50% of its antidepressant activity despite reaching concentrations of ~10-fold higher than that of the parent drug. Oxidation of the bupropion side chain results in the formation of a glycine conjugate of meta-chlorobenzoic acid, which is then excreted as the major urinary metabolite. The potency and toxicity of the metabolites relative to bupropion have not been fully characterized. However, it has been demonstrated in an antidepressant screening test in mice that hydroxybupropion is one-half as potent as bupropion, while threohydrobupropion and erythrohydrobupropion are 5-fold less potent than bupropion. This may be of clinical importance because the plasma concentrations of the metabolites are as high as or higher than those of bupropion. Bupropion and its metabolites exhibit linear kinetics following chronic administration of 300 to 450 mg per day. •Metabolism (Drug B): Primarily hepatic, cotinine is the primary metabolite. •Route of elimination (Drug A): Bupropion is extensively metabolized in humans. Oxidation of the bupropion side chain results in the formation of a glycine conjugate of metachlorobenzoic acid, which is then excreted as the major urinary metabolite. Following oral administration of 200 mg of 14C-bupropion in humans, 87% and 10% of the radioactive dose were recovered in the urine and feces, respectively. However, the fraction of the oral dose of bupropion excreted unchanged was only 0.5%, a finding consistent with the extensive metabolism of bupropion. •Route of elimination (Drug B): About 10% of the nicotine absorbed is excreted unchanged in the urine. •Half-life (Drug A): 24 hours •Half-life (Drug B): Cotinine has a half life of 15-20 hours, while nicotine has a half life of 1-3 hours •Clearance (Drug A): No clearance available •Clearance (Drug B): 1.2 L/min [healthy adult smoker] •Toxicity (Drug A): Symptoms of overdose include seizures, hallucinations, loss of consciousness, tachycardia, and cardiac arrest. •Toxicity (Drug B): Symptoms of overdose include nausea, abdominal pain, vomiting, diarrhea, diaphoresis, flushing, dizziness, disturbed hearing and vision, confusion, weakness, palpitations, altered respiration and hypotension. LD 50 = 24 mg/kg (orally in mice). •Brand Names (Drug A): Aplenzin, Auvelity, Budeprion, Contrave, Forfivo, Wellbutrin, Zyban •Brand Names (Drug B): Habitrol, Nicoderm C-Q, Nicorelief, Nicorette, Nicotrol •Synonyms (Drug A): No synonyms listed •Synonyms (Drug B): (S)-Nicotine Nicotina Nicotine Nicotine betadex Nicotine polacrilex Nikotin Nikotyna •Summary (Drug A): Bupropion is a norepinephrine and dopamine reuptake inhibitor used in the treatment of major depressive disorder (MDD), seasonal affective disorder (SAD), and as an aid to smoking cessation. •Summary (Drug B): Nicotine is a stimulatory alkaloid found in tobacco products that is often used for the relief of nicotine withdrawal symptoms and as an aid to smoking cessation. Output: When a CYP2B6 substrate is coadministered with another CYP2B6 substrate, both substrates will invariably compete with each other to be metabolized by the limited quantities of CYP2B6 isoenzymes present in the body. When one substrate is subsequently capable of 'out-competing' the other, this other substrate will have its CYP2B6 facilitated metabolism stalled or otherwise decreased for a time, resulting in increased serum concentrations of this substrate and/or an increased risk, incidence, or severity of adverse effects associated with exposure to this substrate. The severity of the interaction is moderate.

Does Bupropion and Nifedipine interact?

•Drug A: Bupropion •Drug B: Nifedipine •Severity: MAJOR •Description: The metabolism of Nifedipine can be decreased when combined with Bupropion. •Extended Description: The subject drug is a strong CYP2D6 inhibitor and the affected drug is metabolized by CYP2D6. Concomitant administration may decrease the metabolism of the affected drug, which could increase serum concentrations as well as the risk and severity of adverse effects. •Indication (Drug A): Bupropion is indicated for the treatment of major depressive disorder (MDD), seasonal affective disorder (SAD), and as an aid to smoking cessation. When used in combination with naltrexone as the marketed product ContraveⓇ, bupropion is indicated as an adjunct to a reduced-calorie diet and increased physical activity for chronic weight management in adults with an initial body mass index (BMI) of: 30 kg/m^2 or greater (obese) or 27 kg/m^2 or greater (overweight) in the presence of at least one weight-related comorbid condition (e.g., hypertension, type 2 diabetes mellitus, or dyslipidemia). Bupropion is also used off-label as a first-line treatment in patients with ADHD and comorbid bipolar disorder when used as an adjunct to mood stabilizers. •Indication (Drug B): Nifedipine capsules are indicated to treat vasospastic angina and chronic stable angina. Extended release tablets are indicated to treat vasospastic angina, chronic stable angina, and hypertension. •Pharmacodynamics (Drug A): Bupropion is chemically unrelated to tricyclic, tetracyclic, selective serotonin re-uptake inhibitors, or other known antidepressant agents. Compared to classical tricyclic antidepressants, Bupropion is a relatively weak inhibitor of the neuronal uptake of norepinephrine and dopamine. In addition, Bupropion does not inhibit monoamine oxidase. Bupropion has been found to be essentially inactive at the serotonin transporter (SERT)(IC50 >10 000 nM), however both bupropion and its primary metabolite hydroxybupropion have been found to block the function of cation-selective serotonin type 3A receptors (5-HT3ARs). Bupropion produces dose-related central nervous system (CNS) stimulant effects in animals, as evidenced by increased locomotor activity, increased rates of responding in various schedule-controlled operant behaviour tasks, and, at high doses, induction of mild stereotyped behaviour. Due to these stimulant effects and selective activity at dopamine and norepinephrine receptors, bupropion has been identified as having an abuse potential. Bupropion has a similar structure to the controlled substance Cathinone, and has been identified as having mild amphetamine-like activity, particularly when inhaled or injected. Bupropion is also known to lower the seizure threshold, making any pre-existing seizure conditions a contraindication to its use. This risk is exacerbated when bupropion is combined with other drugs or substances that lower the seizure threshold, such as cocaine, or in clinical situations that would increase the risk of a seizure such as abrupt alcohol or benzodiazepine withdrawal. As norepinephrine has been shown to have anticonvulsant properties, bupropion's inhibitory effects on NET are thought to contribute to its pro-convulsant activity. Bupropion has been shown to increase blood pressure and pose a risk for exacerbation of unmanaged or pre-existing hypertension, however, clinical trials of bupropion in smokers with CVD have not identified an increased incidence of CV events including stroke or heart attack. In clinical trials, the mean increase in systolic blood pressure associated with the use of bupropion was found to be 1.3 mmHg. •Pharmacodynamics (Drug B): Nifedipine is an inhibitor of L-type voltage gated calcium channels that reduces blood pressure and increases oxygen supply to the heart. Immediate release nifedipine's duration of action requires dosing 3 times daily. Nifedipine dosing is generally 10-120mg daily. Patients should be counselled regarding the risk of excessive hypotension, angina, and myocardial infarction. •Mechanism of action (Drug A): Bupropion is a norepinephrine/dopamine-reuptake inhibitor (NDRI) that exerts its pharmacological effects by weakly inhibiting the enzymes involved in the uptake of the neurotransmitters norepinephrine and dopamine from the synaptic cleft, therefore prolonging their duration of action within the neuronal synapse and the downstream effects of these neurotransmitters. More specifically, bupropion binds to the norepinephrine transporter (NET) and the dopamine transporter (DAT). Bupropion was originally classified as an "atypical" antidepressant because it does not exert the same effects as the classical antidepressants such as Monoamine Oxidase Inhibitors (MAOIs), Tricyclic Antidepressants (TCAs), or Selective Serotonin Reuptake Inhibitors (SSRIs). While it has comparable effectiveness to typical first-line options for the treatment of depression such as SSRIs, bupropion is a unique option for the treatment of MDD as it lacks any clinically relevant serotonergic effects, typical of other mood medications, or any effects on histamine or adrenaline receptors. Lack of activity at these receptors results in a more tolerable side effect profile; bupropion is less likely to cause sexual side effects, sedation, or weight gain as compared to SSRIs or TCAs, for example. When used as an aid to smoking cessation, bupropion is thought to confer its anti-craving and anti-withdrawal effects by inhibiting dopamine reuptake, which is thought to be involved in the reward pathways associated with nicotine, and through the antagonism of the nicotinic acetylcholinergic receptor (AChR), thereby blunting the effects of nicotine. Furthermore, the stimulatory effects produced by bupropion in the central nervous system are similar to nicotine's effects, making low doses of bupropion a suitable option as a nicotine substitute. When used in combination with naltrexone in the marketed product ContraveⓇ for chronic weight management, the two components are thought to have effects on areas of the brain involved in the regulation of food intake. This includes the hypothalamus, which is involved in appetite regulation, and the mesolimbic dopamine circuit, which is involved in reward pathways. Studies have shown that the combined activity of bupropion and naltrexone increase the firing rate of hypothalamic pro-opiomelanocortin (POMC) neurons and blockade of opioid receptor-mediated POMC auto-inhibition, which are associated with a reduction in food intake and increased energy expenditure. This combination was also found to reduce food intake when injected directly into the ventral tegmental area of the mesolimbic circuit in mice, which is an area associated with the regulation of reward pathways. •Mechanism of action (Drug B): Nifedipine blocks voltage gated L-type calcium channels in vascular smooth muscle and myocardial cells. This blockage prevents the entry of calcium ions into cells during depolarization, reducing peripheral arterial vascular resistance and dilating coronary arteries. These actions reduce blood pressure and increase the supply of oxygen to the heart, alleviating angina. •Absorption (Drug A): Bupropion is currently available in 3 distinct, but bioequivalent formulations: immediate release (IR), sustained-release (SR), and extended-release (XL). Immediate Release Formulation In humans, following oral administration of bupropion hydrochloride tablets, peak plasma bupropion concentrations are usually achieved within 2 hours. IR formulations provide a short duration of action and are therefore generally dosed three times per day. Sustained Release Formulation In humans, following oral administration of bupropion hydrochloride sustained-release tablets (SR), peak plasma concentration (Cmax) of bupropion is usually achieved within 3 hours. SR formulations provide a 12-hour extended release of medication and are therefore generally dosed twice per day. Extended Release Formulation Following single oral administration of bupropion hydrochloride extended-release tablets (XL) to healthy volunteers, the median time to peak plasma concentrations for bupropion was approximately 5 hours. The presence of food did not affect the peak concentration or area under the curve of bupropion. XL formulations provide a 24-hour extended release of medication and are therefore generally dosed once per day/ In a trial comparing chronic dosing with bupropion hydrochloride extended-release tablets (SR) 150 mg twice daily to bupropion immediate-release formulation 100 mg 3 times daily, the steady state Cmax for bupropion after bupropion hydrochloride sustained-release tablets (SR) administration was approximately 85% of those achieved after bupropion immediate-release formulation administration. Exposure (AUC) to bupropion was equivalent for both formulations. Bioequivalence was also demonstrated for all three major active metabolites (i.e., hydroxybupropion, threohydrobupropion and erythrohydrobupropion) for both Cmax and AUC. Thus, at steady state, bupropion hydrochloride sustained-release tablets (SR) given twice daily, and the immediate-release formulation of bupropion given 3 times daily, are essentially bioequivalent for both bupropion and the 3 quantitatively important metabolites. Furthermore, in a study comparing 14-day dosing with bupropion hydrochloride extended-release tablets (XL), 300 mg once-daily to the immediate-release formulation of bupropion at 100 mg 3 times daily, equivalence was demonstrated for peak plasma concentration and area under the curve for bupropion and the three metabolites (hydroxybupropion, threohydrobupropion, and erythrohydrobupropion). Additionally, in a study comparing 14-day dosing with bupropion hydrochloride extended-release tablets (XL) 300 mg once daily to the sustained-release formulation of bupropion at 150 mg 2 times daily, equivalence was demonstrated for peak plasma concentration and area under the curve for bupropion and the three metabolites. Bupropion hydrochloride extended-release tablets (SR) can be taken with or without food. Bupropion Cmax and AUC were increased by 11% to 35% and 16% to 19%, respectively, when bupropion hydrochloride extended-release tablets (SR) was administered with food to healthy volunteers in three trials. The food effect is not considered clinically significant. Following a single-dose administration of bupropion hydrochloride extended-release tablets (SR) in humans, Cmax of bupropion's metabolite hydroxybupropion occurs approximately 6 hours post-dose and is approximately 10 times the peak level of the parent drug at steady state. The elimination half-life of hydroxybupropion is approximately 20 (±5) hours and its AUC at steady state is about 17 times that of bupropion. The times to peak concentrations for the erythrohydrobupropion and threohydrobupropion metabolites are similar to that of the hydroxybupropion metabolite. However, their elimination half-lives are longer, 33(±10) and 37 (±13) hours, respectively, and steady-state AUCs are 1.5 and 7 times that of bupropion, respectively. •Absorption (Drug B): Sublingual dosing leads to a C max of 10ng/mL, with a T max of 50min, and an AUC of 25ng*h/mL. Oral dosing leads to a C max of 82ng/mL, with a T max of 28min, and an AUC of 152ng*h/mL. Nifedipine is a Biopharmaceutics Classification System Class II drug, meaning it has low solubility and high intestinal permeability. It is almost completely absorbed in the gastrointestinal tract but has a bioavilability of 45-68%, partly due to first pass metabolism. •Volume of distribution (Drug A): No volume of distribution available •Volume of distribution (Drug B): The steady state volume of distribution of nifedipine is 0.62-0.77L/kg and the volume of distribution of the central compartment is 0.25-0.29L/kg. •Protein binding (Drug A): In vitro tests show that bupropion is 84% bound to human plasma proteins at concentrations up to 200 mcg per mL. The extent of protein binding of the hydroxybupropion metabolite is similar to that for bupropion, whereas the extent of protein binding of the threohydrobupropion metabolite is about half that seen with bupropion. •Protein binding (Drug B): Nifedipine is 92-98% protein bound in serum. Nifedipine is 97±12% bound in a 40g/L solution of pure albumin. Nifedipine is 51.4±5.9% protein bound in a 50mg/100mL solution of alpha-1-acid glycoprotein, and 75.5±3.5% protein bound in a 150mg/mL solution. •Metabolism (Drug A): Bupropion is extensively metabolized in humans. Three metabolites are active: hydroxybupropion, which is formed via hydroxylation of the tert-butyl group of bupropion, and the amino-alcohol isomers, threohydrobupropion and erythrohydrobupropion, which are formed via reduction of the carbonyl group. In vitro findings suggest that CYP2B6 is the principal isoenzyme involved in the formation of hydroxybupropion, while cytochrome P450 enzymes are not involved in the formation of threohydrobupropion. Hydroxybupropion has been shown to have the same affinity as bupropion for the norepinephrine transporter (NET) but approximately 50% of its antidepressant activity despite reaching concentrations of ~10-fold higher than that of the parent drug. Oxidation of the bupropion side chain results in the formation of a glycine conjugate of meta-chlorobenzoic acid, which is then excreted as the major urinary metabolite. The potency and toxicity of the metabolites relative to bupropion have not been fully characterized. However, it has been demonstrated in an antidepressant screening test in mice that hydroxybupropion is one-half as potent as bupropion, while threohydrobupropion and erythrohydrobupropion are 5-fold less potent than bupropion. This may be of clinical importance because the plasma concentrations of the metabolites are as high as or higher than those of bupropion. Bupropion and its metabolites exhibit linear kinetics following chronic administration of 300 to 450 mg per day. •Metabolism (Drug B): Nifedipine is predominantly metabolized by CYP3A4. Nifedipine is predominantly metabolized to 2,6-dimethyl-4-(2-nitrophenyl)-5-methoxycarbonyl-pyridine-3-carboxylic acid, and then further metabolized to 2-hydroxymethyl-pyridine carboxylic acid. Nifedipine is also minorly metabolized to dehydronifedipine. •Route of elimination (Drug A): Bupropion is extensively metabolized in humans. Oxidation of the bupropion side chain results in the formation of a glycine conjugate of metachlorobenzoic acid, which is then excreted as the major urinary metabolite. Following oral administration of 200 mg of 14C-bupropion in humans, 87% and 10% of the radioactive dose were recovered in the urine and feces, respectively. However, the fraction of the oral dose of bupropion excreted unchanged was only 0.5%, a finding consistent with the extensive metabolism of bupropion. •Route of elimination (Drug B): Nifedipine is 60-80% recovered in the urine as inactive water soluble metabolites, and the rest is eliminated in the feces as metabolites. •Half-life (Drug A): 24 hours •Half-life (Drug B): The terminal elimination half life of nifedipine is approximately 2 hours. •Clearance (Drug A): No clearance available •Clearance (Drug B): The total body clearance of nifedipine is 450-700mL/min. •Toxicity (Drug A): Symptoms of overdose include seizures, hallucinations, loss of consciousness, tachycardia, and cardiac arrest. •Toxicity (Drug B): The oral LD 50 in rats is 1022mg/kg and in mice is 202mg/kg. Patients experiencing an overdose may present with hypotension, sinus node dysfunction, atrioventricular node dysfunction, and reflex tachycardia. Overdose may be managed by monitoring cardiovascular and respiratory function; elevating extremities; and administering vasopressors, fluids, and calcium infusions. •Brand Names (Drug A): Aplenzin, Auvelity, Budeprion, Contrave, Forfivo, Wellbutrin, Zyban •Brand Names (Drug B): Adalat, Afeditab CR, Nifediac, Nifedical, Procardia •Synonyms (Drug A): No synonyms listed •Synonyms (Drug B): Nifedipine Nifedipino Nifedipinum •Summary (Drug A): Bupropion is a norepinephrine and dopamine reuptake inhibitor used in the treatment of major depressive disorder (MDD), seasonal affective disorder (SAD), and as an aid to smoking cessation. •Summary (Drug B): Nifedipine is a dihydropyridine calcium channel blocker indicated for the management of several subtypes of angina pectoris, and hypertension.

The subject drug is a strong CYP2D6 inhibitor and the affected drug is metabolized by CYP2D6. Concomitant administration may decrease the metabolism of the affected drug, which could increase serum concentrations as well as the risk and severity of adverse effects. The severity of the interaction is major.

Question: Does Bupropion and Nifedipine interact? Information: •Drug A: Bupropion •Drug B: Nifedipine •Severity: MAJOR •Description: The metabolism of Nifedipine can be decreased when combined with Bupropion. •Extended Description: The subject drug is a strong CYP2D6 inhibitor and the affected drug is metabolized by CYP2D6. Concomitant administration may decrease the metabolism of the affected drug, which could increase serum concentrations as well as the risk and severity of adverse effects. •Indication (Drug A): Bupropion is indicated for the treatment of major depressive disorder (MDD), seasonal affective disorder (SAD), and as an aid to smoking cessation. When used in combination with naltrexone as the marketed product ContraveⓇ, bupropion is indicated as an adjunct to a reduced-calorie diet and increased physical activity for chronic weight management in adults with an initial body mass index (BMI) of: 30 kg/m^2 or greater (obese) or 27 kg/m^2 or greater (overweight) in the presence of at least one weight-related comorbid condition (e.g., hypertension, type 2 diabetes mellitus, or dyslipidemia). Bupropion is also used off-label as a first-line treatment in patients with ADHD and comorbid bipolar disorder when used as an adjunct to mood stabilizers. •Indication (Drug B): Nifedipine capsules are indicated to treat vasospastic angina and chronic stable angina. Extended release tablets are indicated to treat vasospastic angina, chronic stable angina, and hypertension. •Pharmacodynamics (Drug A): Bupropion is chemically unrelated to tricyclic, tetracyclic, selective serotonin re-uptake inhibitors, or other known antidepressant agents. Compared to classical tricyclic antidepressants, Bupropion is a relatively weak inhibitor of the neuronal uptake of norepinephrine and dopamine. In addition, Bupropion does not inhibit monoamine oxidase. Bupropion has been found to be essentially inactive at the serotonin transporter (SERT)(IC50 >10 000 nM), however both bupropion and its primary metabolite hydroxybupropion have been found to block the function of cation-selective serotonin type 3A receptors (5-HT3ARs). Bupropion produces dose-related central nervous system (CNS) stimulant effects in animals, as evidenced by increased locomotor activity, increased rates of responding in various schedule-controlled operant behaviour tasks, and, at high doses, induction of mild stereotyped behaviour. Due to these stimulant effects and selective activity at dopamine and norepinephrine receptors, bupropion has been identified as having an abuse potential. Bupropion has a similar structure to the controlled substance Cathinone, and has been identified as having mild amphetamine-like activity, particularly when inhaled or injected. Bupropion is also known to lower the seizure threshold, making any pre-existing seizure conditions a contraindication to its use. This risk is exacerbated when bupropion is combined with other drugs or substances that lower the seizure threshold, such as cocaine, or in clinical situations that would increase the risk of a seizure such as abrupt alcohol or benzodiazepine withdrawal. As norepinephrine has been shown to have anticonvulsant properties, bupropion's inhibitory effects on NET are thought to contribute to its pro-convulsant activity. Bupropion has been shown to increase blood pressure and pose a risk for exacerbation of unmanaged or pre-existing hypertension, however, clinical trials of bupropion in smokers with CVD have not identified an increased incidence of CV events including stroke or heart attack. In clinical trials, the mean increase in systolic blood pressure associated with the use of bupropion was found to be 1.3 mmHg. •Pharmacodynamics (Drug B): Nifedipine is an inhibitor of L-type voltage gated calcium channels that reduces blood pressure and increases oxygen supply to the heart. Immediate release nifedipine's duration of action requires dosing 3 times daily. Nifedipine dosing is generally 10-120mg daily. Patients should be counselled regarding the risk of excessive hypotension, angina, and myocardial infarction. •Mechanism of action (Drug A): Bupropion is a norepinephrine/dopamine-reuptake inhibitor (NDRI) that exerts its pharmacological effects by weakly inhibiting the enzymes involved in the uptake of the neurotransmitters norepinephrine and dopamine from the synaptic cleft, therefore prolonging their duration of action within the neuronal synapse and the downstream effects of these neurotransmitters. More specifically, bupropion binds to the norepinephrine transporter (NET) and the dopamine transporter (DAT). Bupropion was originally classified as an "atypical" antidepressant because it does not exert the same effects as the classical antidepressants such as Monoamine Oxidase Inhibitors (MAOIs), Tricyclic Antidepressants (TCAs), or Selective Serotonin Reuptake Inhibitors (SSRIs). While it has comparable effectiveness to typical first-line options for the treatment of depression such as SSRIs, bupropion is a unique option for the treatment of MDD as it lacks any clinically relevant serotonergic effects, typical of other mood medications, or any effects on histamine or adrenaline receptors. Lack of activity at these receptors results in a more tolerable side effect profile; bupropion is less likely to cause sexual side effects, sedation, or weight gain as compared to SSRIs or TCAs, for example. When used as an aid to smoking cessation, bupropion is thought to confer its anti-craving and anti-withdrawal effects by inhibiting dopamine reuptake, which is thought to be involved in the reward pathways associated with nicotine, and through the antagonism of the nicotinic acetylcholinergic receptor (AChR), thereby blunting the effects of nicotine. Furthermore, the stimulatory effects produced by bupropion in the central nervous system are similar to nicotine's effects, making low doses of bupropion a suitable option as a nicotine substitute. When used in combination with naltrexone in the marketed product ContraveⓇ for chronic weight management, the two components are thought to have effects on areas of the brain involved in the regulation of food intake. This includes the hypothalamus, which is involved in appetite regulation, and the mesolimbic dopamine circuit, which is involved in reward pathways. Studies have shown that the combined activity of bupropion and naltrexone increase the firing rate of hypothalamic pro-opiomelanocortin (POMC) neurons and blockade of opioid receptor-mediated POMC auto-inhibition, which are associated with a reduction in food intake and increased energy expenditure. This combination was also found to reduce food intake when injected directly into the ventral tegmental area of the mesolimbic circuit in mice, which is an area associated with the regulation of reward pathways. •Mechanism of action (Drug B): Nifedipine blocks voltage gated L-type calcium channels in vascular smooth muscle and myocardial cells. This blockage prevents the entry of calcium ions into cells during depolarization, reducing peripheral arterial vascular resistance and dilating coronary arteries. These actions reduce blood pressure and increase the supply of oxygen to the heart, alleviating angina. •Absorption (Drug A): Bupropion is currently available in 3 distinct, but bioequivalent formulations: immediate release (IR), sustained-release (SR), and extended-release (XL). Immediate Release Formulation In humans, following oral administration of bupropion hydrochloride tablets, peak plasma bupropion concentrations are usually achieved within 2 hours. IR formulations provide a short duration of action and are therefore generally dosed three times per day. Sustained Release Formulation In humans, following oral administration of bupropion hydrochloride sustained-release tablets (SR), peak plasma concentration (Cmax) of bupropion is usually achieved within 3 hours. SR formulations provide a 12-hour extended release of medication and are therefore generally dosed twice per day. Extended Release Formulation Following single oral administration of bupropion hydrochloride extended-release tablets (XL) to healthy volunteers, the median time to peak plasma concentrations for bupropion was approximately 5 hours. The presence of food did not affect the peak concentration or area under the curve of bupropion. XL formulations provide a 24-hour extended release of medication and are therefore generally dosed once per day/ In a trial comparing chronic dosing with bupropion hydrochloride extended-release tablets (SR) 150 mg twice daily to bupropion immediate-release formulation 100 mg 3 times daily, the steady state Cmax for bupropion after bupropion hydrochloride sustained-release tablets (SR) administration was approximately 85% of those achieved after bupropion immediate-release formulation administration. Exposure (AUC) to bupropion was equivalent for both formulations. Bioequivalence was also demonstrated for all three major active metabolites (i.e., hydroxybupropion, threohydrobupropion and erythrohydrobupropion) for both Cmax and AUC. Thus, at steady state, bupropion hydrochloride sustained-release tablets (SR) given twice daily, and the immediate-release formulation of bupropion given 3 times daily, are essentially bioequivalent for both bupropion and the 3 quantitatively important metabolites. Furthermore, in a study comparing 14-day dosing with bupropion hydrochloride extended-release tablets (XL), 300 mg once-daily to the immediate-release formulation of bupropion at 100 mg 3 times daily, equivalence was demonstrated for peak plasma concentration and area under the curve for bupropion and the three metabolites (hydroxybupropion, threohydrobupropion, and erythrohydrobupropion). Additionally, in a study comparing 14-day dosing with bupropion hydrochloride extended-release tablets (XL) 300 mg once daily to the sustained-release formulation of bupropion at 150 mg 2 times daily, equivalence was demonstrated for peak plasma concentration and area under the curve for bupropion and the three metabolites. Bupropion hydrochloride extended-release tablets (SR) can be taken with or without food. Bupropion Cmax and AUC were increased by 11% to 35% and 16% to 19%, respectively, when bupropion hydrochloride extended-release tablets (SR) was administered with food to healthy volunteers in three trials. The food effect is not considered clinically significant. Following a single-dose administration of bupropion hydrochloride extended-release tablets (SR) in humans, Cmax of bupropion's metabolite hydroxybupropion occurs approximately 6 hours post-dose and is approximately 10 times the peak level of the parent drug at steady state. The elimination half-life of hydroxybupropion is approximately 20 (±5) hours and its AUC at steady state is about 17 times that of bupropion. The times to peak concentrations for the erythrohydrobupropion and threohydrobupropion metabolites are similar to that of the hydroxybupropion metabolite. However, their elimination half-lives are longer, 33(±10) and 37 (±13) hours, respectively, and steady-state AUCs are 1.5 and 7 times that of bupropion, respectively. •Absorption (Drug B): Sublingual dosing leads to a C max of 10ng/mL, with a T max of 50min, and an AUC of 25ng*h/mL. Oral dosing leads to a C max of 82ng/mL, with a T max of 28min, and an AUC of 152ng*h/mL. Nifedipine is a Biopharmaceutics Classification System Class II drug, meaning it has low solubility and high intestinal permeability. It is almost completely absorbed in the gastrointestinal tract but has a bioavilability of 45-68%, partly due to first pass metabolism. •Volume of distribution (Drug A): No volume of distribution available •Volume of distribution (Drug B): The steady state volume of distribution of nifedipine is 0.62-0.77L/kg and the volume of distribution of the central compartment is 0.25-0.29L/kg. •Protein binding (Drug A): In vitro tests show that bupropion is 84% bound to human plasma proteins at concentrations up to 200 mcg per mL. The extent of protein binding of the hydroxybupropion metabolite is similar to that for bupropion, whereas the extent of protein binding of the threohydrobupropion metabolite is about half that seen with bupropion. •Protein binding (Drug B): Nifedipine is 92-98% protein bound in serum. Nifedipine is 97±12% bound in a 40g/L solution of pure albumin. Nifedipine is 51.4±5.9% protein bound in a 50mg/100mL solution of alpha-1-acid glycoprotein, and 75.5±3.5% protein bound in a 150mg/mL solution. •Metabolism (Drug A): Bupropion is extensively metabolized in humans. Three metabolites are active: hydroxybupropion, which is formed via hydroxylation of the tert-butyl group of bupropion, and the amino-alcohol isomers, threohydrobupropion and erythrohydrobupropion, which are formed via reduction of the carbonyl group. In vitro findings suggest that CYP2B6 is the principal isoenzyme involved in the formation of hydroxybupropion, while cytochrome P450 enzymes are not involved in the formation of threohydrobupropion. Hydroxybupropion has been shown to have the same affinity as bupropion for the norepinephrine transporter (NET) but approximately 50% of its antidepressant activity despite reaching concentrations of ~10-fold higher than that of the parent drug. Oxidation of the bupropion side chain results in the formation of a glycine conjugate of meta-chlorobenzoic acid, which is then excreted as the major urinary metabolite. The potency and toxicity of the metabolites relative to bupropion have not been fully characterized. However, it has been demonstrated in an antidepressant screening test in mice that hydroxybupropion is one-half as potent as bupropion, while threohydrobupropion and erythrohydrobupropion are 5-fold less potent than bupropion. This may be of clinical importance because the plasma concentrations of the metabolites are as high as or higher than those of bupropion. Bupropion and its metabolites exhibit linear kinetics following chronic administration of 300 to 450 mg per day. •Metabolism (Drug B): Nifedipine is predominantly metabolized by CYP3A4. Nifedipine is predominantly metabolized to 2,6-dimethyl-4-(2-nitrophenyl)-5-methoxycarbonyl-pyridine-3-carboxylic acid, and then further metabolized to 2-hydroxymethyl-pyridine carboxylic acid. Nifedipine is also minorly metabolized to dehydronifedipine. •Route of elimination (Drug A): Bupropion is extensively metabolized in humans. Oxidation of the bupropion side chain results in the formation of a glycine conjugate of metachlorobenzoic acid, which is then excreted as the major urinary metabolite. Following oral administration of 200 mg of 14C-bupropion in humans, 87% and 10% of the radioactive dose were recovered in the urine and feces, respectively. However, the fraction of the oral dose of bupropion excreted unchanged was only 0.5%, a finding consistent with the extensive metabolism of bupropion. •Route of elimination (Drug B): Nifedipine is 60-80% recovered in the urine as inactive water soluble metabolites, and the rest is eliminated in the feces as metabolites. •Half-life (Drug A): 24 hours •Half-life (Drug B): The terminal elimination half life of nifedipine is approximately 2 hours. •Clearance (Drug A): No clearance available •Clearance (Drug B): The total body clearance of nifedipine is 450-700mL/min. •Toxicity (Drug A): Symptoms of overdose include seizures, hallucinations, loss of consciousness, tachycardia, and cardiac arrest. •Toxicity (Drug B): The oral LD 50 in rats is 1022mg/kg and in mice is 202mg/kg. Patients experiencing an overdose may present with hypotension, sinus node dysfunction, atrioventricular node dysfunction, and reflex tachycardia. Overdose may be managed by monitoring cardiovascular and respiratory function; elevating extremities; and administering vasopressors, fluids, and calcium infusions. •Brand Names (Drug A): Aplenzin, Auvelity, Budeprion, Contrave, Forfivo, Wellbutrin, Zyban •Brand Names (Drug B): Adalat, Afeditab CR, Nifediac, Nifedical, Procardia •Synonyms (Drug A): No synonyms listed •Synonyms (Drug B): Nifedipine Nifedipino Nifedipinum •Summary (Drug A): Bupropion is a norepinephrine and dopamine reuptake inhibitor used in the treatment of major depressive disorder (MDD), seasonal affective disorder (SAD), and as an aid to smoking cessation. •Summary (Drug B): Nifedipine is a dihydropyridine calcium channel blocker indicated for the management of several subtypes of angina pectoris, and hypertension. Output: The subject drug is a strong CYP2D6 inhibitor and the affected drug is metabolized by CYP2D6. Concomitant administration may decrease the metabolism of the affected drug, which could increase serum concentrations as well as the risk and severity of adverse effects. The severity of the interaction is major.

Does Bupropion and Nilutamide interact?

•Drug A: Bupropion •Drug B: Nilutamide •Severity: MODERATE •Description: The metabolism of Bupropion can be decreased when combined with Nilutamide. •Extended Description: The subject drug is known to be an inhibitor of CYP2C9 while the affected drug is reported to be metabolized by CYP2C9. Concomitant administration of these agents can cause an increase in the serum concentration of the affected drug due to decreased metabolism by CYP2C9, which may result in increased incidence and/or severity of adverse effects related to the affected drug. •Indication (Drug A): Bupropion is indicated for the treatment of major depressive disorder (MDD), seasonal affective disorder (SAD), and as an aid to smoking cessation. When used in combination with naltrexone as the marketed product ContraveⓇ, bupropion is indicated as an adjunct to a reduced-calorie diet and increased physical activity for chronic weight management in adults with an initial body mass index (BMI) of: 30 kg/m^2 or greater (obese) or 27 kg/m^2 or greater (overweight) in the presence of at least one weight-related comorbid condition (e.g., hypertension, type 2 diabetes mellitus, or dyslipidemia). Bupropion is also used off-label as a first-line treatment in patients with ADHD and comorbid bipolar disorder when used as an adjunct to mood stabilizers. •Indication (Drug B): For use in combination with surgical castration for the treatment of metastatic prostate cancer involving distant lymph nodes, bone, or visceral organs (Stage D2). •Pharmacodynamics (Drug A): Bupropion is chemically unrelated to tricyclic, tetracyclic, selective serotonin re-uptake inhibitors, or other known antidepressant agents. Compared to classical tricyclic antidepressants, Bupropion is a relatively weak inhibitor of the neuronal uptake of norepinephrine and dopamine. In addition, Bupropion does not inhibit monoamine oxidase. Bupropion has been found to be essentially inactive at the serotonin transporter (SERT)(IC50 >10 000 nM), however both bupropion and its primary metabolite hydroxybupropion have been found to block the function of cation-selective serotonin type 3A receptors (5-HT3ARs). Bupropion produces dose-related central nervous system (CNS) stimulant effects in animals, as evidenced by increased locomotor activity, increased rates of responding in various schedule-controlled operant behaviour tasks, and, at high doses, induction of mild stereotyped behaviour. Due to these stimulant effects and selective activity at dopamine and norepinephrine receptors, bupropion has been identified as having an abuse potential. Bupropion has a similar structure to the controlled substance Cathinone, and has been identified as having mild amphetamine-like activity, particularly when inhaled or injected. Bupropion is also known to lower the seizure threshold, making any pre-existing seizure conditions a contraindication to its use. This risk is exacerbated when bupropion is combined with other drugs or substances that lower the seizure threshold, such as cocaine, or in clinical situations that would increase the risk of a seizure such as abrupt alcohol or benzodiazepine withdrawal. As norepinephrine has been shown to have anticonvulsant properties, bupropion's inhibitory effects on NET are thought to contribute to its pro-convulsant activity. Bupropion has been shown to increase blood pressure and pose a risk for exacerbation of unmanaged or pre-existing hypertension, however, clinical trials of bupropion in smokers with CVD have not identified an increased incidence of CV events including stroke or heart attack. In clinical trials, the mean increase in systolic blood pressure associated with the use of bupropion was found to be 1.3 mmHg. •Pharmacodynamics (Drug B): Nilutamide is an antineoplastic hormonal agent primarily used in the treatment of prostate cancer. Nilutamide is a pure, nonsteroidal anti-androgen with affinity for androgen receptors (but not for progestogen, estrogen, or glucocorticoid receptors). Consequently, Nilutamide blocks the action of androgens of adrenal and testicular origin that stimulate the growth of normal and malignant prostatic tissue. Prostate cancer is mostly androgen-dependent and can be treated with surgical or chemical castration. To date, antiandrogen monotherapy has not consistently been shown to be equivalent to castration. The relative binding affinity of nilutamide at the androgen receptor is less than that of bicalutamide, but similar to that of hydroxuflutamide. •Mechanism of action (Drug A): Bupropion is a norepinephrine/dopamine-reuptake inhibitor (NDRI) that exerts its pharmacological effects by weakly inhibiting the enzymes involved in the uptake of the neurotransmitters norepinephrine and dopamine from the synaptic cleft, therefore prolonging their duration of action within the neuronal synapse and the downstream effects of these neurotransmitters. More specifically, bupropion binds to the norepinephrine transporter (NET) and the dopamine transporter (DAT). Bupropion was originally classified as an "atypical" antidepressant because it does not exert the same effects as the classical antidepressants such as Monoamine Oxidase Inhibitors (MAOIs), Tricyclic Antidepressants (TCAs), or Selective Serotonin Reuptake Inhibitors (SSRIs). While it has comparable effectiveness to typical first-line options for the treatment of depression such as SSRIs, bupropion is a unique option for the treatment of MDD as it lacks any clinically relevant serotonergic effects, typical of other mood medications, or any effects on histamine or adrenaline receptors. Lack of activity at these receptors results in a more tolerable side effect profile; bupropion is less likely to cause sexual side effects, sedation, or weight gain as compared to SSRIs or TCAs, for example. When used as an aid to smoking cessation, bupropion is thought to confer its anti-craving and anti-withdrawal effects by inhibiting dopamine reuptake, which is thought to be involved in the reward pathways associated with nicotine, and through the antagonism of the nicotinic acetylcholinergic receptor (AChR), thereby blunting the effects of nicotine. Furthermore, the stimulatory effects produced by bupropion in the central nervous system are similar to nicotine's effects, making low doses of bupropion a suitable option as a nicotine substitute. When used in combination with naltrexone in the marketed product ContraveⓇ for chronic weight management, the two components are thought to have effects on areas of the brain involved in the regulation of food intake. This includes the hypothalamus, which is involved in appetite regulation, and the mesolimbic dopamine circuit, which is involved in reward pathways. Studies have shown that the combined activity of bupropion and naltrexone increase the firing rate of hypothalamic pro-opiomelanocortin (POMC) neurons and blockade of opioid receptor-mediated POMC auto-inhibition, which are associated with a reduction in food intake and increased energy expenditure. This combination was also found to reduce food intake when injected directly into the ventral tegmental area of the mesolimbic circuit in mice, which is an area associated with the regulation of reward pathways. •Mechanism of action (Drug B): Nilutamide competes with androgen for the binding of androgen receptors, consequently blocking the action of androgens of adrenal and testicular origin that stimulate the growth of normal and malignant prostatic tissue. This blockade of androgen receptors may result in growth arrest or transient tumor regression through inhibition of androgen-dependent DNA and protein synthesis. •Absorption (Drug A): Bupropion is currently available in 3 distinct, but bioequivalent formulations: immediate release (IR), sustained-release (SR), and extended-release (XL). Immediate Release Formulation In humans, following oral administration of bupropion hydrochloride tablets, peak plasma bupropion concentrations are usually achieved within 2 hours. IR formulations provide a short duration of action and are therefore generally dosed three times per day. Sustained Release Formulation In humans, following oral administration of bupropion hydrochloride sustained-release tablets (SR), peak plasma concentration (Cmax) of bupropion is usually achieved within 3 hours. SR formulations provide a 12-hour extended release of medication and are therefore generally dosed twice per day. Extended Release Formulation Following single oral administration of bupropion hydrochloride extended-release tablets (XL) to healthy volunteers, the median time to peak plasma concentrations for bupropion was approximately 5 hours. The presence of food did not affect the peak concentration or area under the curve of bupropion. XL formulations provide a 24-hour extended release of medication and are therefore generally dosed once per day/ In a trial comparing chronic dosing with bupropion hydrochloride extended-release tablets (SR) 150 mg twice daily to bupropion immediate-release formulation 100 mg 3 times daily, the steady state Cmax for bupropion after bupropion hydrochloride sustained-release tablets (SR) administration was approximately 85% of those achieved after bupropion immediate-release formulation administration. Exposure (AUC) to bupropion was equivalent for both formulations. Bioequivalence was also demonstrated for all three major active metabolites (i.e., hydroxybupropion, threohydrobupropion and erythrohydrobupropion) for both Cmax and AUC. Thus, at steady state, bupropion hydrochloride sustained-release tablets (SR) given twice daily, and the immediate-release formulation of bupropion given 3 times daily, are essentially bioequivalent for both bupropion and the 3 quantitatively important metabolites. Furthermore, in a study comparing 14-day dosing with bupropion hydrochloride extended-release tablets (XL), 300 mg once-daily to the immediate-release formulation of bupropion at 100 mg 3 times daily, equivalence was demonstrated for peak plasma concentration and area under the curve for bupropion and the three metabolites (hydroxybupropion, threohydrobupropion, and erythrohydrobupropion). Additionally, in a study comparing 14-day dosing with bupropion hydrochloride extended-release tablets (XL) 300 mg once daily to the sustained-release formulation of bupropion at 150 mg 2 times daily, equivalence was demonstrated for peak plasma concentration and area under the curve for bupropion and the three metabolites. Bupropion hydrochloride extended-release tablets (SR) can be taken with or without food. Bupropion Cmax and AUC were increased by 11% to 35% and 16% to 19%, respectively, when bupropion hydrochloride extended-release tablets (SR) was administered with food to healthy volunteers in three trials. The food effect is not considered clinically significant. Following a single-dose administration of bupropion hydrochloride extended-release tablets (SR) in humans, Cmax of bupropion's metabolite hydroxybupropion occurs approximately 6 hours post-dose and is approximately 10 times the peak level of the parent drug at steady state. The elimination half-life of hydroxybupropion is approximately 20 (±5) hours and its AUC at steady state is about 17 times that of bupropion. The times to peak concentrations for the erythrohydrobupropion and threohydrobupropion metabolites are similar to that of the hydroxybupropion metabolite. However, their elimination half-lives are longer, 33(±10) and 37 (±13) hours, respectively, and steady-state AUCs are 1.5 and 7 times that of bupropion, respectively. •Absorption (Drug B): Rapidly and completely absorbed, yielding high and persistent plasma concentrations. •Volume of distribution (Drug A): No volume of distribution available •Volume of distribution (Drug B): No volume of distribution available •Protein binding (Drug A): In vitro tests show that bupropion is 84% bound to human plasma proteins at concentrations up to 200 mcg per mL. The extent of protein binding of the hydroxybupropion metabolite is similar to that for bupropion, whereas the extent of protein binding of the threohydrobupropion metabolite is about half that seen with bupropion. •Protein binding (Drug B): No protein binding available •Metabolism (Drug A): Bupropion is extensively metabolized in humans. Three metabolites are active: hydroxybupropion, which is formed via hydroxylation of the tert-butyl group of bupropion, and the amino-alcohol isomers, threohydrobupropion and erythrohydrobupropion, which are formed via reduction of the carbonyl group. In vitro findings suggest that CYP2B6 is the principal isoenzyme involved in the formation of hydroxybupropion, while cytochrome P450 enzymes are not involved in the formation of threohydrobupropion. Hydroxybupropion has been shown to have the same affinity as bupropion for the norepinephrine transporter (NET) but approximately 50% of its antidepressant activity despite reaching concentrations of ~10-fold higher than that of the parent drug. Oxidation of the bupropion side chain results in the formation of a glycine conjugate of meta-chlorobenzoic acid, which is then excreted as the major urinary metabolite. The potency and toxicity of the metabolites relative to bupropion have not been fully characterized. However, it has been demonstrated in an antidepressant screening test in mice that hydroxybupropion is one-half as potent as bupropion, while threohydrobupropion and erythrohydrobupropion are 5-fold less potent than bupropion. This may be of clinical importance because the plasma concentrations of the metabolites are as high as or higher than those of bupropion. Bupropion and its metabolites exhibit linear kinetics following chronic administration of 300 to 450 mg per day. •Metabolism (Drug B): The results of a human metabolism study using 14C-radiolabelled tablets show that nilutamide is extensively metabolized and less than 2% of the drug is excreted unchanged in urine after 5 days. •Route of elimination (Drug A): Bupropion is extensively metabolized in humans. Oxidation of the bupropion side chain results in the formation of a glycine conjugate of metachlorobenzoic acid, which is then excreted as the major urinary metabolite. Following oral administration of 200 mg of 14C-bupropion in humans, 87% and 10% of the radioactive dose were recovered in the urine and feces, respectively. However, the fraction of the oral dose of bupropion excreted unchanged was only 0.5%, a finding consistent with the extensive metabolism of bupropion. •Route of elimination (Drug B): Nilutamide is extensively metabolized andless than 2% of the drug is excreted unchanged in urine after 5 days. Fecal elimination is negligible, ranging from 1.4% to 7% of the dose after 4 to 5 days. •Half-life (Drug A): 24 hours •Half-life (Drug B): 38.0-59.1 hours •Clearance (Drug A): No clearance available •Clearance (Drug B): No clearance available •Toxicity (Drug A): Symptoms of overdose include seizures, hallucinations, loss of consciousness, tachycardia, and cardiac arrest. •Toxicity (Drug B): Symptoms of overdose include dizziness, general discomfort, headache, nausea, and vomiting. •Brand Names (Drug A): Aplenzin, Auvelity, Budeprion, Contrave, Forfivo, Wellbutrin, Zyban •Brand Names (Drug B): Anandron, Nilandron •Synonyms (Drug A): No synonyms listed •Synonyms (Drug B): Nilutamida Nilutamide Nilutamidum •Summary (Drug A): Bupropion is a norepinephrine and dopamine reuptake inhibitor used in the treatment of major depressive disorder (MDD), seasonal affective disorder (SAD), and as an aid to smoking cessation. •Summary (Drug B): Nilutamide is an antineoplastic hormone used to treat prostate cancer.

The subject drug is known to be an inhibitor of CYP2C9 while the affected drug is reported to be metabolized by CYP2C9. Concomitant administration of these agents can cause an increase in the serum concentration of the affected drug due to decreased metabolism by CYP2C9, which may result in increased incidence and/or severity of adverse effects related to the affected drug. The severity of the interaction is moderate.

Question: Does Bupropion and Nilutamide interact? Information: •Drug A: Bupropion •Drug B: Nilutamide •Severity: MODERATE •Description: The metabolism of Bupropion can be decreased when combined with Nilutamide. •Extended Description: The subject drug is known to be an inhibitor of CYP2C9 while the affected drug is reported to be metabolized by CYP2C9. Concomitant administration of these agents can cause an increase in the serum concentration of the affected drug due to decreased metabolism by CYP2C9, which may result in increased incidence and/or severity of adverse effects related to the affected drug. •Indication (Drug A): Bupropion is indicated for the treatment of major depressive disorder (MDD), seasonal affective disorder (SAD), and as an aid to smoking cessation. When used in combination with naltrexone as the marketed product ContraveⓇ, bupropion is indicated as an adjunct to a reduced-calorie diet and increased physical activity for chronic weight management in adults with an initial body mass index (BMI) of: 30 kg/m^2 or greater (obese) or 27 kg/m^2 or greater (overweight) in the presence of at least one weight-related comorbid condition (e.g., hypertension, type 2 diabetes mellitus, or dyslipidemia). Bupropion is also used off-label as a first-line treatment in patients with ADHD and comorbid bipolar disorder when used as an adjunct to mood stabilizers. •Indication (Drug B): For use in combination with surgical castration for the treatment of metastatic prostate cancer involving distant lymph nodes, bone, or visceral organs (Stage D2). •Pharmacodynamics (Drug A): Bupropion is chemically unrelated to tricyclic, tetracyclic, selective serotonin re-uptake inhibitors, or other known antidepressant agents. Compared to classical tricyclic antidepressants, Bupropion is a relatively weak inhibitor of the neuronal uptake of norepinephrine and dopamine. In addition, Bupropion does not inhibit monoamine oxidase. Bupropion has been found to be essentially inactive at the serotonin transporter (SERT)(IC50 >10 000 nM), however both bupropion and its primary metabolite hydroxybupropion have been found to block the function of cation-selective serotonin type 3A receptors (5-HT3ARs). Bupropion produces dose-related central nervous system (CNS) stimulant effects in animals, as evidenced by increased locomotor activity, increased rates of responding in various schedule-controlled operant behaviour tasks, and, at high doses, induction of mild stereotyped behaviour. Due to these stimulant effects and selective activity at dopamine and norepinephrine receptors, bupropion has been identified as having an abuse potential. Bupropion has a similar structure to the controlled substance Cathinone, and has been identified as having mild amphetamine-like activity, particularly when inhaled or injected. Bupropion is also known to lower the seizure threshold, making any pre-existing seizure conditions a contraindication to its use. This risk is exacerbated when bupropion is combined with other drugs or substances that lower the seizure threshold, such as cocaine, or in clinical situations that would increase the risk of a seizure such as abrupt alcohol or benzodiazepine withdrawal. As norepinephrine has been shown to have anticonvulsant properties, bupropion's inhibitory effects on NET are thought to contribute to its pro-convulsant activity. Bupropion has been shown to increase blood pressure and pose a risk for exacerbation of unmanaged or pre-existing hypertension, however, clinical trials of bupropion in smokers with CVD have not identified an increased incidence of CV events including stroke or heart attack. In clinical trials, the mean increase in systolic blood pressure associated with the use of bupropion was found to be 1.3 mmHg. •Pharmacodynamics (Drug B): Nilutamide is an antineoplastic hormonal agent primarily used in the treatment of prostate cancer. Nilutamide is a pure, nonsteroidal anti-androgen with affinity for androgen receptors (but not for progestogen, estrogen, or glucocorticoid receptors). Consequently, Nilutamide blocks the action of androgens of adrenal and testicular origin that stimulate the growth of normal and malignant prostatic tissue. Prostate cancer is mostly androgen-dependent and can be treated with surgical or chemical castration. To date, antiandrogen monotherapy has not consistently been shown to be equivalent to castration. The relative binding affinity of nilutamide at the androgen receptor is less than that of bicalutamide, but similar to that of hydroxuflutamide. •Mechanism of action (Drug A): Bupropion is a norepinephrine/dopamine-reuptake inhibitor (NDRI) that exerts its pharmacological effects by weakly inhibiting the enzymes involved in the uptake of the neurotransmitters norepinephrine and dopamine from the synaptic cleft, therefore prolonging their duration of action within the neuronal synapse and the downstream effects of these neurotransmitters. More specifically, bupropion binds to the norepinephrine transporter (NET) and the dopamine transporter (DAT). Bupropion was originally classified as an "atypical" antidepressant because it does not exert the same effects as the classical antidepressants such as Monoamine Oxidase Inhibitors (MAOIs), Tricyclic Antidepressants (TCAs), or Selective Serotonin Reuptake Inhibitors (SSRIs). While it has comparable effectiveness to typical first-line options for the treatment of depression such as SSRIs, bupropion is a unique option for the treatment of MDD as it lacks any clinically relevant serotonergic effects, typical of other mood medications, or any effects on histamine or adrenaline receptors. Lack of activity at these receptors results in a more tolerable side effect profile; bupropion is less likely to cause sexual side effects, sedation, or weight gain as compared to SSRIs or TCAs, for example. When used as an aid to smoking cessation, bupropion is thought to confer its anti-craving and anti-withdrawal effects by inhibiting dopamine reuptake, which is thought to be involved in the reward pathways associated with nicotine, and through the antagonism of the nicotinic acetylcholinergic receptor (AChR), thereby blunting the effects of nicotine. Furthermore, the stimulatory effects produced by bupropion in the central nervous system are similar to nicotine's effects, making low doses of bupropion a suitable option as a nicotine substitute. When used in combination with naltrexone in the marketed product ContraveⓇ for chronic weight management, the two components are thought to have effects on areas of the brain involved in the regulation of food intake. This includes the hypothalamus, which is involved in appetite regulation, and the mesolimbic dopamine circuit, which is involved in reward pathways. Studies have shown that the combined activity of bupropion and naltrexone increase the firing rate of hypothalamic pro-opiomelanocortin (POMC) neurons and blockade of opioid receptor-mediated POMC auto-inhibition, which are associated with a reduction in food intake and increased energy expenditure. This combination was also found to reduce food intake when injected directly into the ventral tegmental area of the mesolimbic circuit in mice, which is an area associated with the regulation of reward pathways. •Mechanism of action (Drug B): Nilutamide competes with androgen for the binding of androgen receptors, consequently blocking the action of androgens of adrenal and testicular origin that stimulate the growth of normal and malignant prostatic tissue. This blockade of androgen receptors may result in growth arrest or transient tumor regression through inhibition of androgen-dependent DNA and protein synthesis. •Absorption (Drug A): Bupropion is currently available in 3 distinct, but bioequivalent formulations: immediate release (IR), sustained-release (SR), and extended-release (XL). Immediate Release Formulation In humans, following oral administration of bupropion hydrochloride tablets, peak plasma bupropion concentrations are usually achieved within 2 hours. IR formulations provide a short duration of action and are therefore generally dosed three times per day. Sustained Release Formulation In humans, following oral administration of bupropion hydrochloride sustained-release tablets (SR), peak plasma concentration (Cmax) of bupropion is usually achieved within 3 hours. SR formulations provide a 12-hour extended release of medication and are therefore generally dosed twice per day. Extended Release Formulation Following single oral administration of bupropion hydrochloride extended-release tablets (XL) to healthy volunteers, the median time to peak plasma concentrations for bupropion was approximately 5 hours. The presence of food did not affect the peak concentration or area under the curve of bupropion. XL formulations provide a 24-hour extended release of medication and are therefore generally dosed once per day/ In a trial comparing chronic dosing with bupropion hydrochloride extended-release tablets (SR) 150 mg twice daily to bupropion immediate-release formulation 100 mg 3 times daily, the steady state Cmax for bupropion after bupropion hydrochloride sustained-release tablets (SR) administration was approximately 85% of those achieved after bupropion immediate-release formulation administration. Exposure (AUC) to bupropion was equivalent for both formulations. Bioequivalence was also demonstrated for all three major active metabolites (i.e., hydroxybupropion, threohydrobupropion and erythrohydrobupropion) for both Cmax and AUC. Thus, at steady state, bupropion hydrochloride sustained-release tablets (SR) given twice daily, and the immediate-release formulation of bupropion given 3 times daily, are essentially bioequivalent for both bupropion and the 3 quantitatively important metabolites. Furthermore, in a study comparing 14-day dosing with bupropion hydrochloride extended-release tablets (XL), 300 mg once-daily to the immediate-release formulation of bupropion at 100 mg 3 times daily, equivalence was demonstrated for peak plasma concentration and area under the curve for bupropion and the three metabolites (hydroxybupropion, threohydrobupropion, and erythrohydrobupropion). Additionally, in a study comparing 14-day dosing with bupropion hydrochloride extended-release tablets (XL) 300 mg once daily to the sustained-release formulation of bupropion at 150 mg 2 times daily, equivalence was demonstrated for peak plasma concentration and area under the curve for bupropion and the three metabolites. Bupropion hydrochloride extended-release tablets (SR) can be taken with or without food. Bupropion Cmax and AUC were increased by 11% to 35% and 16% to 19%, respectively, when bupropion hydrochloride extended-release tablets (SR) was administered with food to healthy volunteers in three trials. The food effect is not considered clinically significant. Following a single-dose administration of bupropion hydrochloride extended-release tablets (SR) in humans, Cmax of bupropion's metabolite hydroxybupropion occurs approximately 6 hours post-dose and is approximately 10 times the peak level of the parent drug at steady state. The elimination half-life of hydroxybupropion is approximately 20 (±5) hours and its AUC at steady state is about 17 times that of bupropion. The times to peak concentrations for the erythrohydrobupropion and threohydrobupropion metabolites are similar to that of the hydroxybupropion metabolite. However, their elimination half-lives are longer, 33(±10) and 37 (±13) hours, respectively, and steady-state AUCs are 1.5 and 7 times that of bupropion, respectively. •Absorption (Drug B): Rapidly and completely absorbed, yielding high and persistent plasma concentrations. •Volume of distribution (Drug A): No volume of distribution available •Volume of distribution (Drug B): No volume of distribution available •Protein binding (Drug A): In vitro tests show that bupropion is 84% bound to human plasma proteins at concentrations up to 200 mcg per mL. The extent of protein binding of the hydroxybupropion metabolite is similar to that for bupropion, whereas the extent of protein binding of the threohydrobupropion metabolite is about half that seen with bupropion. •Protein binding (Drug B): No protein binding available •Metabolism (Drug A): Bupropion is extensively metabolized in humans. Three metabolites are active: hydroxybupropion, which is formed via hydroxylation of the tert-butyl group of bupropion, and the amino-alcohol isomers, threohydrobupropion and erythrohydrobupropion, which are formed via reduction of the carbonyl group. In vitro findings suggest that CYP2B6 is the principal isoenzyme involved in the formation of hydroxybupropion, while cytochrome P450 enzymes are not involved in the formation of threohydrobupropion. Hydroxybupropion has been shown to have the same affinity as bupropion for the norepinephrine transporter (NET) but approximately 50% of its antidepressant activity despite reaching concentrations of ~10-fold higher than that of the parent drug. Oxidation of the bupropion side chain results in the formation of a glycine conjugate of meta-chlorobenzoic acid, which is then excreted as the major urinary metabolite. The potency and toxicity of the metabolites relative to bupropion have not been fully characterized. However, it has been demonstrated in an antidepressant screening test in mice that hydroxybupropion is one-half as potent as bupropion, while threohydrobupropion and erythrohydrobupropion are 5-fold less potent than bupropion. This may be of clinical importance because the plasma concentrations of the metabolites are as high as or higher than those of bupropion. Bupropion and its metabolites exhibit linear kinetics following chronic administration of 300 to 450 mg per day. •Metabolism (Drug B): The results of a human metabolism study using 14C-radiolabelled tablets show that nilutamide is extensively metabolized and less than 2% of the drug is excreted unchanged in urine after 5 days. •Route of elimination (Drug A): Bupropion is extensively metabolized in humans. Oxidation of the bupropion side chain results in the formation of a glycine conjugate of metachlorobenzoic acid, which is then excreted as the major urinary metabolite. Following oral administration of 200 mg of 14C-bupropion in humans, 87% and 10% of the radioactive dose were recovered in the urine and feces, respectively. However, the fraction of the oral dose of bupropion excreted unchanged was only 0.5%, a finding consistent with the extensive metabolism of bupropion. •Route of elimination (Drug B): Nilutamide is extensively metabolized andless than 2% of the drug is excreted unchanged in urine after 5 days. Fecal elimination is negligible, ranging from 1.4% to 7% of the dose after 4 to 5 days. •Half-life (Drug A): 24 hours •Half-life (Drug B): 38.0-59.1 hours •Clearance (Drug A): No clearance available •Clearance (Drug B): No clearance available •Toxicity (Drug A): Symptoms of overdose include seizures, hallucinations, loss of consciousness, tachycardia, and cardiac arrest. •Toxicity (Drug B): Symptoms of overdose include dizziness, general discomfort, headache, nausea, and vomiting. •Brand Names (Drug A): Aplenzin, Auvelity, Budeprion, Contrave, Forfivo, Wellbutrin, Zyban •Brand Names (Drug B): Anandron, Nilandron •Synonyms (Drug A): No synonyms listed •Synonyms (Drug B): Nilutamida Nilutamide Nilutamidum •Summary (Drug A): Bupropion is a norepinephrine and dopamine reuptake inhibitor used in the treatment of major depressive disorder (MDD), seasonal affective disorder (SAD), and as an aid to smoking cessation. •Summary (Drug B): Nilutamide is an antineoplastic hormone used to treat prostate cancer. Output: The subject drug is known to be an inhibitor of CYP2C9 while the affected drug is reported to be metabolized by CYP2C9. Concomitant administration of these agents can cause an increase in the serum concentration of the affected drug due to decreased metabolism by CYP2C9, which may result in increased incidence and/or severity of adverse effects related to the affected drug. The severity of the interaction is moderate.

Does Bupropion and Nimesulide interact?

•Drug A: Bupropion •Drug B: Nimesulide •Severity: MINOR •Description: Nimesulide may decrease the excretion rate of Bupropion which could result in a higher serum level. •Extended Description: The subject drug is a nephrotoxic agent that may potentially impair renal function and decrease the excretion of drugs that mainly undergo renal excretion as the principal mode of clearance, such as the affected drug. Attenuated renal excretion of the affected drug may increase drug concentrations, leading to an elevated risk for drug-related adverse effects. •Indication (Drug A): Bupropion is indicated for the treatment of major depressive disorder (MDD), seasonal affective disorder (SAD), and as an aid to smoking cessation. When used in combination with naltrexone as the marketed product ContraveⓇ, bupropion is indicated as an adjunct to a reduced-calorie diet and increased physical activity for chronic weight management in adults with an initial body mass index (BMI) of: 30 kg/m^2 or greater (obese) or 27 kg/m^2 or greater (overweight) in the presence of at least one weight-related comorbid condition (e.g., hypertension, type 2 diabetes mellitus, or dyslipidemia). Bupropion is also used off-label as a first-line treatment in patients with ADHD and comorbid bipolar disorder when used as an adjunct to mood stabilizers. •Indication (Drug B): For the treatment of acute pain, the symptomatic treatment of osteoarthritis and primary dysmenorrhoea in adolescents and adults above 12 years old. •Pharmacodynamics (Drug A): Bupropion is chemically unrelated to tricyclic, tetracyclic, selective serotonin re-uptake inhibitors, or other known antidepressant agents. Compared to classical tricyclic antidepressants, Bupropion is a relatively weak inhibitor of the neuronal uptake of norepinephrine and dopamine. In addition, Bupropion does not inhibit monoamine oxidase. Bupropion has been found to be essentially inactive at the serotonin transporter (SERT)(IC50 >10 000 nM), however both bupropion and its primary metabolite hydroxybupropion have been found to block the function of cation-selective serotonin type 3A receptors (5-HT3ARs). Bupropion produces dose-related central nervous system (CNS) stimulant effects in animals, as evidenced by increased locomotor activity, increased rates of responding in various schedule-controlled operant behaviour tasks, and, at high doses, induction of mild stereotyped behaviour. Due to these stimulant effects and selective activity at dopamine and norepinephrine receptors, bupropion has been identified as having an abuse potential. Bupropion has a similar structure to the controlled substance Cathinone, and has been identified as having mild amphetamine-like activity, particularly when inhaled or injected. Bupropion is also known to lower the seizure threshold, making any pre-existing seizure conditions a contraindication to its use. This risk is exacerbated when bupropion is combined with other drugs or substances that lower the seizure threshold, such as cocaine, or in clinical situations that would increase the risk of a seizure such as abrupt alcohol or benzodiazepine withdrawal. As norepinephrine has been shown to have anticonvulsant properties, bupropion's inhibitory effects on NET are thought to contribute to its pro-convulsant activity. Bupropion has been shown to increase blood pressure and pose a risk for exacerbation of unmanaged or pre-existing hypertension, however, clinical trials of bupropion in smokers with CVD have not identified an increased incidence of CV events including stroke or heart attack. In clinical trials, the mean increase in systolic blood pressure associated with the use of bupropion was found to be 1.3 mmHg. •Pharmacodynamics (Drug B): Food, gender and advanced age have negligible effects on nimesulide pharmacokinetics. •Mechanism of action (Drug A): Bupropion is a norepinephrine/dopamine-reuptake inhibitor (NDRI) that exerts its pharmacological effects by weakly inhibiting the enzymes involved in the uptake of the neurotransmitters norepinephrine and dopamine from the synaptic cleft, therefore prolonging their duration of action within the neuronal synapse and the downstream effects of these neurotransmitters. More specifically, bupropion binds to the norepinephrine transporter (NET) and the dopamine transporter (DAT). Bupropion was originally classified as an "atypical" antidepressant because it does not exert the same effects as the classical antidepressants such as Monoamine Oxidase Inhibitors (MAOIs), Tricyclic Antidepressants (TCAs), or Selective Serotonin Reuptake Inhibitors (SSRIs). While it has comparable effectiveness to typical first-line options for the treatment of depression such as SSRIs, bupropion is a unique option for the treatment of MDD as it lacks any clinically relevant serotonergic effects, typical of other mood medications, or any effects on histamine or adrenaline receptors. Lack of activity at these receptors results in a more tolerable side effect profile; bupropion is less likely to cause sexual side effects, sedation, or weight gain as compared to SSRIs or TCAs, for example. When used as an aid to smoking cessation, bupropion is thought to confer its anti-craving and anti-withdrawal effects by inhibiting dopamine reuptake, which is thought to be involved in the reward pathways associated with nicotine, and through the antagonism of the nicotinic acetylcholinergic receptor (AChR), thereby blunting the effects of nicotine. Furthermore, the stimulatory effects produced by bupropion in the central nervous system are similar to nicotine's effects, making low doses of bupropion a suitable option as a nicotine substitute. When used in combination with naltrexone in the marketed product ContraveⓇ for chronic weight management, the two components are thought to have effects on areas of the brain involved in the regulation of food intake. This includes the hypothalamus, which is involved in appetite regulation, and the mesolimbic dopamine circuit, which is involved in reward pathways. Studies have shown that the combined activity of bupropion and naltrexone increase the firing rate of hypothalamic pro-opiomelanocortin (POMC) neurons and blockade of opioid receptor-mediated POMC auto-inhibition, which are associated with a reduction in food intake and increased energy expenditure. This combination was also found to reduce food intake when injected directly into the ventral tegmental area of the mesolimbic circuit in mice, which is an area associated with the regulation of reward pathways. •Mechanism of action (Drug B): The therapeutic effects of Nimesulide are the result of its complete mode of action which targets a number of key mediators of the inflammatory process such as: COX-2 mediated prostaglandins, free radicals, proteolytic enzymes and histamine. •Absorption (Drug A): Bupropion is currently available in 3 distinct, but bioequivalent formulations: immediate release (IR), sustained-release (SR), and extended-release (XL). Immediate Release Formulation In humans, following oral administration of bupropion hydrochloride tablets, peak plasma bupropion concentrations are usually achieved within 2 hours. IR formulations provide a short duration of action and are therefore generally dosed three times per day. Sustained Release Formulation In humans, following oral administration of bupropion hydrochloride sustained-release tablets (SR), peak plasma concentration (Cmax) of bupropion is usually achieved within 3 hours. SR formulations provide a 12-hour extended release of medication and are therefore generally dosed twice per day. Extended Release Formulation Following single oral administration of bupropion hydrochloride extended-release tablets (XL) to healthy volunteers, the median time to peak plasma concentrations for bupropion was approximately 5 hours. The presence of food did not affect the peak concentration or area under the curve of bupropion. XL formulations provide a 24-hour extended release of medication and are therefore generally dosed once per day/ In a trial comparing chronic dosing with bupropion hydrochloride extended-release tablets (SR) 150 mg twice daily to bupropion immediate-release formulation 100 mg 3 times daily, the steady state Cmax for bupropion after bupropion hydrochloride sustained-release tablets (SR) administration was approximately 85% of those achieved after bupropion immediate-release formulation administration. Exposure (AUC) to bupropion was equivalent for both formulations. Bioequivalence was also demonstrated for all three major active metabolites (i.e., hydroxybupropion, threohydrobupropion and erythrohydrobupropion) for both Cmax and AUC. Thus, at steady state, bupropion hydrochloride sustained-release tablets (SR) given twice daily, and the immediate-release formulation of bupropion given 3 times daily, are essentially bioequivalent for both bupropion and the 3 quantitatively important metabolites. Furthermore, in a study comparing 14-day dosing with bupropion hydrochloride extended-release tablets (XL), 300 mg once-daily to the immediate-release formulation of bupropion at 100 mg 3 times daily, equivalence was demonstrated for peak plasma concentration and area under the curve for bupropion and the three metabolites (hydroxybupropion, threohydrobupropion, and erythrohydrobupropion). Additionally, in a study comparing 14-day dosing with bupropion hydrochloride extended-release tablets (XL) 300 mg once daily to the sustained-release formulation of bupropion at 150 mg 2 times daily, equivalence was demonstrated for peak plasma concentration and area under the curve for bupropion and the three metabolites. Bupropion hydrochloride extended-release tablets (SR) can be taken with or without food. Bupropion Cmax and AUC were increased by 11% to 35% and 16% to 19%, respectively, when bupropion hydrochloride extended-release tablets (SR) was administered with food to healthy volunteers in three trials. The food effect is not considered clinically significant. Following a single-dose administration of bupropion hydrochloride extended-release tablets (SR) in humans, Cmax of bupropion's metabolite hydroxybupropion occurs approximately 6 hours post-dose and is approximately 10 times the peak level of the parent drug at steady state. The elimination half-life of hydroxybupropion is approximately 20 (±5) hours and its AUC at steady state is about 17 times that of bupropion. The times to peak concentrations for the erythrohydrobupropion and threohydrobupropion metabolites are similar to that of the hydroxybupropion metabolite. However, their elimination half-lives are longer, 33(±10) and 37 (±13) hours, respectively, and steady-state AUCs are 1.5 and 7 times that of bupropion, respectively. •Absorption (Drug B): Rapidly absorbed following oral administration. •Volume of distribution (Drug A): No volume of distribution available •Volume of distribution (Drug B): No volume of distribution available •Protein binding (Drug A): In vitro tests show that bupropion is 84% bound to human plasma proteins at concentrations up to 200 mcg per mL. The extent of protein binding of the hydroxybupropion metabolite is similar to that for bupropion, whereas the extent of protein binding of the threohydrobupropion metabolite is about half that seen with bupropion. •Protein binding (Drug B): >97.5% •Metabolism (Drug A): Bupropion is extensively metabolized in humans. Three metabolites are active: hydroxybupropion, which is formed via hydroxylation of the tert-butyl group of bupropion, and the amino-alcohol isomers, threohydrobupropion and erythrohydrobupropion, which are formed via reduction of the carbonyl group. In vitro findings suggest that CYP2B6 is the principal isoenzyme involved in the formation of hydroxybupropion, while cytochrome P450 enzymes are not involved in the formation of threohydrobupropion. Hydroxybupropion has been shown to have the same affinity as bupropion for the norepinephrine transporter (NET) but approximately 50% of its antidepressant activity despite reaching concentrations of ~10-fold higher than that of the parent drug. Oxidation of the bupropion side chain results in the formation of a glycine conjugate of meta-chlorobenzoic acid, which is then excreted as the major urinary metabolite. The potency and toxicity of the metabolites relative to bupropion have not been fully characterized. However, it has been demonstrated in an antidepressant screening test in mice that hydroxybupropion is one-half as potent as bupropion, while threohydrobupropion and erythrohydrobupropion are 5-fold less potent than bupropion. This may be of clinical importance because the plasma concentrations of the metabolites are as high as or higher than those of bupropion. Bupropion and its metabolites exhibit linear kinetics following chronic administration of 300 to 450 mg per day. •Metabolism (Drug B): Hepatic. Extensive biotransformation, mainly to 4-hydroxynimesulide (which also appears to be biologically active). •Route of elimination (Drug A): Bupropion is extensively metabolized in humans. Oxidation of the bupropion side chain results in the formation of a glycine conjugate of metachlorobenzoic acid, which is then excreted as the major urinary metabolite. Following oral administration of 200 mg of 14C-bupropion in humans, 87% and 10% of the radioactive dose were recovered in the urine and feces, respectively. However, the fraction of the oral dose of bupropion excreted unchanged was only 0.5%, a finding consistent with the extensive metabolism of bupropion. •Route of elimination (Drug B): Renal (50%), fecal (29%) •Half-life (Drug A): 24 hours •Half-life (Drug B): 1.8–4.7 hours •Clearance (Drug A): No clearance available •Clearance (Drug B): No clearance available •Toxicity (Drug A): Symptoms of overdose include seizures, hallucinations, loss of consciousness, tachycardia, and cardiac arrest. •Toxicity (Drug B): Oral TDLO (human): 1.429 mg/kg; Oral TDLO (woman): 2 mg/kg; Oral LD50 (rat): 200 mg/kg; Oral LD50 (mouse): 392 mg/kg •Brand Names (Drug A): Aplenzin, Auvelity, Budeprion, Contrave, Forfivo, Wellbutrin, Zyban •Brand Names (Drug B): No brand names available •Synonyms (Drug A): No synonyms listed •Synonyms (Drug B): No synonyms listed •Summary (Drug A): Bupropion is a norepinephrine and dopamine reuptake inhibitor used in the treatment of major depressive disorder (MDD), seasonal affective disorder (SAD), and as an aid to smoking cessation. •Summary (Drug B): Nimesulide is a cyclooxygenase 2 inhibitor used to treat acute pain and primary dysmenorrhea.

The subject drug is a nephrotoxic agent that may potentially impair renal function and decrease the excretion of drugs that mainly undergo renal excretion as the principal mode of clearance, such as the affected drug. Attenuated renal excretion of the affected drug may increase drug concentrations, leading to an elevated risk for drug-related adverse effects. The severity of the interaction is minor.

Question: Does Bupropion and Nimesulide interact? Information: •Drug A: Bupropion •Drug B: Nimesulide •Severity: MINOR •Description: Nimesulide may decrease the excretion rate of Bupropion which could result in a higher serum level. •Extended Description: The subject drug is a nephrotoxic agent that may potentially impair renal function and decrease the excretion of drugs that mainly undergo renal excretion as the principal mode of clearance, such as the affected drug. Attenuated renal excretion of the affected drug may increase drug concentrations, leading to an elevated risk for drug-related adverse effects. •Indication (Drug A): Bupropion is indicated for the treatment of major depressive disorder (MDD), seasonal affective disorder (SAD), and as an aid to smoking cessation. When used in combination with naltrexone as the marketed product ContraveⓇ, bupropion is indicated as an adjunct to a reduced-calorie diet and increased physical activity for chronic weight management in adults with an initial body mass index (BMI) of: 30 kg/m^2 or greater (obese) or 27 kg/m^2 or greater (overweight) in the presence of at least one weight-related comorbid condition (e.g., hypertension, type 2 diabetes mellitus, or dyslipidemia). Bupropion is also used off-label as a first-line treatment in patients with ADHD and comorbid bipolar disorder when used as an adjunct to mood stabilizers. •Indication (Drug B): For the treatment of acute pain, the symptomatic treatment of osteoarthritis and primary dysmenorrhoea in adolescents and adults above 12 years old. •Pharmacodynamics (Drug A): Bupropion is chemically unrelated to tricyclic, tetracyclic, selective serotonin re-uptake inhibitors, or other known antidepressant agents. Compared to classical tricyclic antidepressants, Bupropion is a relatively weak inhibitor of the neuronal uptake of norepinephrine and dopamine. In addition, Bupropion does not inhibit monoamine oxidase. Bupropion has been found to be essentially inactive at the serotonin transporter (SERT)(IC50 >10 000 nM), however both bupropion and its primary metabolite hydroxybupropion have been found to block the function of cation-selective serotonin type 3A receptors (5-HT3ARs). Bupropion produces dose-related central nervous system (CNS) stimulant effects in animals, as evidenced by increased locomotor activity, increased rates of responding in various schedule-controlled operant behaviour tasks, and, at high doses, induction of mild stereotyped behaviour. Due to these stimulant effects and selective activity at dopamine and norepinephrine receptors, bupropion has been identified as having an abuse potential. Bupropion has a similar structure to the controlled substance Cathinone, and has been identified as having mild amphetamine-like activity, particularly when inhaled or injected. Bupropion is also known to lower the seizure threshold, making any pre-existing seizure conditions a contraindication to its use. This risk is exacerbated when bupropion is combined with other drugs or substances that lower the seizure threshold, such as cocaine, or in clinical situations that would increase the risk of a seizure such as abrupt alcohol or benzodiazepine withdrawal. As norepinephrine has been shown to have anticonvulsant properties, bupropion's inhibitory effects on NET are thought to contribute to its pro-convulsant activity. Bupropion has been shown to increase blood pressure and pose a risk for exacerbation of unmanaged or pre-existing hypertension, however, clinical trials of bupropion in smokers with CVD have not identified an increased incidence of CV events including stroke or heart attack. In clinical trials, the mean increase in systolic blood pressure associated with the use of bupropion was found to be 1.3 mmHg. •Pharmacodynamics (Drug B): Food, gender and advanced age have negligible effects on nimesulide pharmacokinetics. •Mechanism of action (Drug A): Bupropion is a norepinephrine/dopamine-reuptake inhibitor (NDRI) that exerts its pharmacological effects by weakly inhibiting the enzymes involved in the uptake of the neurotransmitters norepinephrine and dopamine from the synaptic cleft, therefore prolonging their duration of action within the neuronal synapse and the downstream effects of these neurotransmitters. More specifically, bupropion binds to the norepinephrine transporter (NET) and the dopamine transporter (DAT). Bupropion was originally classified as an "atypical" antidepressant because it does not exert the same effects as the classical antidepressants such as Monoamine Oxidase Inhibitors (MAOIs), Tricyclic Antidepressants (TCAs), or Selective Serotonin Reuptake Inhibitors (SSRIs). While it has comparable effectiveness to typical first-line options for the treatment of depression such as SSRIs, bupropion is a unique option for the treatment of MDD as it lacks any clinically relevant serotonergic effects, typical of other mood medications, or any effects on histamine or adrenaline receptors. Lack of activity at these receptors results in a more tolerable side effect profile; bupropion is less likely to cause sexual side effects, sedation, or weight gain as compared to SSRIs or TCAs, for example. When used as an aid to smoking cessation, bupropion is thought to confer its anti-craving and anti-withdrawal effects by inhibiting dopamine reuptake, which is thought to be involved in the reward pathways associated with nicotine, and through the antagonism of the nicotinic acetylcholinergic receptor (AChR), thereby blunting the effects of nicotine. Furthermore, the stimulatory effects produced by bupropion in the central nervous system are similar to nicotine's effects, making low doses of bupropion a suitable option as a nicotine substitute. When used in combination with naltrexone in the marketed product ContraveⓇ for chronic weight management, the two components are thought to have effects on areas of the brain involved in the regulation of food intake. This includes the hypothalamus, which is involved in appetite regulation, and the mesolimbic dopamine circuit, which is involved in reward pathways. Studies have shown that the combined activity of bupropion and naltrexone increase the firing rate of hypothalamic pro-opiomelanocortin (POMC) neurons and blockade of opioid receptor-mediated POMC auto-inhibition, which are associated with a reduction in food intake and increased energy expenditure. This combination was also found to reduce food intake when injected directly into the ventral tegmental area of the mesolimbic circuit in mice, which is an area associated with the regulation of reward pathways. •Mechanism of action (Drug B): The therapeutic effects of Nimesulide are the result of its complete mode of action which targets a number of key mediators of the inflammatory process such as: COX-2 mediated prostaglandins, free radicals, proteolytic enzymes and histamine. •Absorption (Drug A): Bupropion is currently available in 3 distinct, but bioequivalent formulations: immediate release (IR), sustained-release (SR), and extended-release (XL). Immediate Release Formulation In humans, following oral administration of bupropion hydrochloride tablets, peak plasma bupropion concentrations are usually achieved within 2 hours. IR formulations provide a short duration of action and are therefore generally dosed three times per day. Sustained Release Formulation In humans, following oral administration of bupropion hydrochloride sustained-release tablets (SR), peak plasma concentration (Cmax) of bupropion is usually achieved within 3 hours. SR formulations provide a 12-hour extended release of medication and are therefore generally dosed twice per day. Extended Release Formulation Following single oral administration of bupropion hydrochloride extended-release tablets (XL) to healthy volunteers, the median time to peak plasma concentrations for bupropion was approximately 5 hours. The presence of food did not affect the peak concentration or area under the curve of bupropion. XL formulations provide a 24-hour extended release of medication and are therefore generally dosed once per day/ In a trial comparing chronic dosing with bupropion hydrochloride extended-release tablets (SR) 150 mg twice daily to bupropion immediate-release formulation 100 mg 3 times daily, the steady state Cmax for bupropion after bupropion hydrochloride sustained-release tablets (SR) administration was approximately 85% of those achieved after bupropion immediate-release formulation administration. Exposure (AUC) to bupropion was equivalent for both formulations. Bioequivalence was also demonstrated for all three major active metabolites (i.e., hydroxybupropion, threohydrobupropion and erythrohydrobupropion) for both Cmax and AUC. Thus, at steady state, bupropion hydrochloride sustained-release tablets (SR) given twice daily, and the immediate-release formulation of bupropion given 3 times daily, are essentially bioequivalent for both bupropion and the 3 quantitatively important metabolites. Furthermore, in a study comparing 14-day dosing with bupropion hydrochloride extended-release tablets (XL), 300 mg once-daily to the immediate-release formulation of bupropion at 100 mg 3 times daily, equivalence was demonstrated for peak plasma concentration and area under the curve for bupropion and the three metabolites (hydroxybupropion, threohydrobupropion, and erythrohydrobupropion). Additionally, in a study comparing 14-day dosing with bupropion hydrochloride extended-release tablets (XL) 300 mg once daily to the sustained-release formulation of bupropion at 150 mg 2 times daily, equivalence was demonstrated for peak plasma concentration and area under the curve for bupropion and the three metabolites. Bupropion hydrochloride extended-release tablets (SR) can be taken with or without food. Bupropion Cmax and AUC were increased by 11% to 35% and 16% to 19%, respectively, when bupropion hydrochloride extended-release tablets (SR) was administered with food to healthy volunteers in three trials. The food effect is not considered clinically significant. Following a single-dose administration of bupropion hydrochloride extended-release tablets (SR) in humans, Cmax of bupropion's metabolite hydroxybupropion occurs approximately 6 hours post-dose and is approximately 10 times the peak level of the parent drug at steady state. The elimination half-life of hydroxybupropion is approximately 20 (±5) hours and its AUC at steady state is about 17 times that of bupropion. The times to peak concentrations for the erythrohydrobupropion and threohydrobupropion metabolites are similar to that of the hydroxybupropion metabolite. However, their elimination half-lives are longer, 33(±10) and 37 (±13) hours, respectively, and steady-state AUCs are 1.5 and 7 times that of bupropion, respectively. •Absorption (Drug B): Rapidly absorbed following oral administration. •Volume of distribution (Drug A): No volume of distribution available •Volume of distribution (Drug B): No volume of distribution available •Protein binding (Drug A): In vitro tests show that bupropion is 84% bound to human plasma proteins at concentrations up to 200 mcg per mL. The extent of protein binding of the hydroxybupropion metabolite is similar to that for bupropion, whereas the extent of protein binding of the threohydrobupropion metabolite is about half that seen with bupropion. •Protein binding (Drug B): >97.5% •Metabolism (Drug A): Bupropion is extensively metabolized in humans. Three metabolites are active: hydroxybupropion, which is formed via hydroxylation of the tert-butyl group of bupropion, and the amino-alcohol isomers, threohydrobupropion and erythrohydrobupropion, which are formed via reduction of the carbonyl group. In vitro findings suggest that CYP2B6 is the principal isoenzyme involved in the formation of hydroxybupropion, while cytochrome P450 enzymes are not involved in the formation of threohydrobupropion. Hydroxybupropion has been shown to have the same affinity as bupropion for the norepinephrine transporter (NET) but approximately 50% of its antidepressant activity despite reaching concentrations of ~10-fold higher than that of the parent drug. Oxidation of the bupropion side chain results in the formation of a glycine conjugate of meta-chlorobenzoic acid, which is then excreted as the major urinary metabolite. The potency and toxicity of the metabolites relative to bupropion have not been fully characterized. However, it has been demonstrated in an antidepressant screening test in mice that hydroxybupropion is one-half as potent as bupropion, while threohydrobupropion and erythrohydrobupropion are 5-fold less potent than bupropion. This may be of clinical importance because the plasma concentrations of the metabolites are as high as or higher than those of bupropion. Bupropion and its metabolites exhibit linear kinetics following chronic administration of 300 to 450 mg per day. •Metabolism (Drug B): Hepatic. Extensive biotransformation, mainly to 4-hydroxynimesulide (which also appears to be biologically active). •Route of elimination (Drug A): Bupropion is extensively metabolized in humans. Oxidation of the bupropion side chain results in the formation of a glycine conjugate of metachlorobenzoic acid, which is then excreted as the major urinary metabolite. Following oral administration of 200 mg of 14C-bupropion in humans, 87% and 10% of the radioactive dose were recovered in the urine and feces, respectively. However, the fraction of the oral dose of bupropion excreted unchanged was only 0.5%, a finding consistent with the extensive metabolism of bupropion. •Route of elimination (Drug B): Renal (50%), fecal (29%) •Half-life (Drug A): 24 hours •Half-life (Drug B): 1.8–4.7 hours •Clearance (Drug A): No clearance available •Clearance (Drug B): No clearance available •Toxicity (Drug A): Symptoms of overdose include seizures, hallucinations, loss of consciousness, tachycardia, and cardiac arrest. •Toxicity (Drug B): Oral TDLO (human): 1.429 mg/kg; Oral TDLO (woman): 2 mg/kg; Oral LD50 (rat): 200 mg/kg; Oral LD50 (mouse): 392 mg/kg •Brand Names (Drug A): Aplenzin, Auvelity, Budeprion, Contrave, Forfivo, Wellbutrin, Zyban •Brand Names (Drug B): No brand names available •Synonyms (Drug A): No synonyms listed •Synonyms (Drug B): No synonyms listed •Summary (Drug A): Bupropion is a norepinephrine and dopamine reuptake inhibitor used in the treatment of major depressive disorder (MDD), seasonal affective disorder (SAD), and as an aid to smoking cessation. •Summary (Drug B): Nimesulide is a cyclooxygenase 2 inhibitor used to treat acute pain and primary dysmenorrhea. Output: The subject drug is a nephrotoxic agent that may potentially impair renal function and decrease the excretion of drugs that mainly undergo renal excretion as the principal mode of clearance, such as the affected drug. Attenuated renal excretion of the affected drug may increase drug concentrations, leading to an elevated risk for drug-related adverse effects. The severity of the interaction is minor.

Does Bupropion and Nirogacestat interact?

•Drug A: Bupropion •Drug B: Nirogacestat •Severity: MAJOR •Description: The metabolism of Nirogacestat can be decreased when combined with Bupropion. •Extended Description: The subject drug is a strong CYP2D6 inhibitor and the affected drug is metabolized by CYP2D6. Concomitant administration may decrease the metabolism of the affected drug, which could increase serum concentrations as well as the risk and severity of adverse effects. •Indication (Drug A): Bupropion is indicated for the treatment of major depressive disorder (MDD), seasonal affective disorder (SAD), and as an aid to smoking cessation. When used in combination with naltrexone as the marketed product ContraveⓇ, bupropion is indicated as an adjunct to a reduced-calorie diet and increased physical activity for chronic weight management in adults with an initial body mass index (BMI) of: 30 kg/m^2 or greater (obese) or 27 kg/m^2 or greater (overweight) in the presence of at least one weight-related comorbid condition (e.g., hypertension, type 2 diabetes mellitus, or dyslipidemia). Bupropion is also used off-label as a first-line treatment in patients with ADHD and comorbid bipolar disorder when used as an adjunct to mood stabilizers. •Indication (Drug B): Nirogacestat is indicated for adult patients with progressing desmoid tumors who require systemic treatment. •Pharmacodynamics (Drug A): Bupropion is chemically unrelated to tricyclic, tetracyclic, selective serotonin re-uptake inhibitors, or other known antidepressant agents. Compared to classical tricyclic antidepressants, Bupropion is a relatively weak inhibitor of the neuronal uptake of norepinephrine and dopamine. In addition, Bupropion does not inhibit monoamine oxidase. Bupropion has been found to be essentially inactive at the serotonin transporter (SERT)(IC50 >10 000 nM), however both bupropion and its primary metabolite hydroxybupropion have been found to block the function of cation-selective serotonin type 3A receptors (5-HT3ARs). Bupropion produces dose-related central nervous system (CNS) stimulant effects in animals, as evidenced by increased locomotor activity, increased rates of responding in various schedule-controlled operant behaviour tasks, and, at high doses, induction of mild stereotyped behaviour. Due to these stimulant effects and selective activity at dopamine and norepinephrine receptors, bupropion has been identified as having an abuse potential. Bupropion has a similar structure to the controlled substance Cathinone, and has been identified as having mild amphetamine-like activity, particularly when inhaled or injected. Bupropion is also known to lower the seizure threshold, making any pre-existing seizure conditions a contraindication to its use. This risk is exacerbated when bupropion is combined with other drugs or substances that lower the seizure threshold, such as cocaine, or in clinical situations that would increase the risk of a seizure such as abrupt alcohol or benzodiazepine withdrawal. As norepinephrine has been shown to have anticonvulsant properties, bupropion's inhibitory effects on NET are thought to contribute to its pro-convulsant activity. Bupropion has been shown to increase blood pressure and pose a risk for exacerbation of unmanaged or pre-existing hypertension, however, clinical trials of bupropion in smokers with CVD have not identified an increased incidence of CV events including stroke or heart attack. In clinical trials, the mean increase in systolic blood pressure associated with the use of bupropion was found to be 1.3 mmHg. •Pharmacodynamics (Drug B): There is an exposure-response relationship between nirogacestat exposure and Grade 3 hypophosphatemia with a higher risk of Grade 3 hypophosphatemia at higher exposure. At the recommended dosage, a mean increase in the QTc interval > 20 ms was not observed. •Mechanism of action (Drug A): Bupropion is a norepinephrine/dopamine-reuptake inhibitor (NDRI) that exerts its pharmacological effects by weakly inhibiting the enzymes involved in the uptake of the neurotransmitters norepinephrine and dopamine from the synaptic cleft, therefore prolonging their duration of action within the neuronal synapse and the downstream effects of these neurotransmitters. More specifically, bupropion binds to the norepinephrine transporter (NET) and the dopamine transporter (DAT). Bupropion was originally classified as an "atypical" antidepressant because it does not exert the same effects as the classical antidepressants such as Monoamine Oxidase Inhibitors (MAOIs), Tricyclic Antidepressants (TCAs), or Selective Serotonin Reuptake Inhibitors (SSRIs). While it has comparable effectiveness to typical first-line options for the treatment of depression such as SSRIs, bupropion is a unique option for the treatment of MDD as it lacks any clinically relevant serotonergic effects, typical of other mood medications, or any effects on histamine or adrenaline receptors. Lack of activity at these receptors results in a more tolerable side effect profile; bupropion is less likely to cause sexual side effects, sedation, or weight gain as compared to SSRIs or TCAs, for example. When used as an aid to smoking cessation, bupropion is thought to confer its anti-craving and anti-withdrawal effects by inhibiting dopamine reuptake, which is thought to be involved in the reward pathways associated with nicotine, and through the antagonism of the nicotinic acetylcholinergic receptor (AChR), thereby blunting the effects of nicotine. Furthermore, the stimulatory effects produced by bupropion in the central nervous system are similar to nicotine's effects, making low doses of bupropion a suitable option as a nicotine substitute. When used in combination with naltrexone in the marketed product ContraveⓇ for chronic weight management, the two components are thought to have effects on areas of the brain involved in the regulation of food intake. This includes the hypothalamus, which is involved in appetite regulation, and the mesolimbic dopamine circuit, which is involved in reward pathways. Studies have shown that the combined activity of bupropion and naltrexone increase the firing rate of hypothalamic pro-opiomelanocortin (POMC) neurons and blockade of opioid receptor-mediated POMC auto-inhibition, which are associated with a reduction in food intake and increased energy expenditure. This combination was also found to reduce food intake when injected directly into the ventral tegmental area of the mesolimbic circuit in mice, which is an area associated with the regulation of reward pathways. •Mechanism of action (Drug B): Nirogacestat is a gamma secretase inhibitor that blocks proteolytic activation of the Notch receptor. When dysregulated, Notch can activate pathways that contribute to tumor growth. •Absorption (Drug A): Bupropion is currently available in 3 distinct, but bioequivalent formulations: immediate release (IR), sustained-release (SR), and extended-release (XL). Immediate Release Formulation In humans, following oral administration of bupropion hydrochloride tablets, peak plasma bupropion concentrations are usually achieved within 2 hours. IR formulations provide a short duration of action and are therefore generally dosed three times per day. Sustained Release Formulation In humans, following oral administration of bupropion hydrochloride sustained-release tablets (SR), peak plasma concentration (Cmax) of bupropion is usually achieved within 3 hours. SR formulations provide a 12-hour extended release of medication and are therefore generally dosed twice per day. Extended Release Formulation Following single oral administration of bupropion hydrochloride extended-release tablets (XL) to healthy volunteers, the median time to peak plasma concentrations for bupropion was approximately 5 hours. The presence of food did not affect the peak concentration or area under the curve of bupropion. XL formulations provide a 24-hour extended release of medication and are therefore generally dosed once per day/ In a trial comparing chronic dosing with bupropion hydrochloride extended-release tablets (SR) 150 mg twice daily to bupropion immediate-release formulation 100 mg 3 times daily, the steady state Cmax for bupropion after bupropion hydrochloride sustained-release tablets (SR) administration was approximately 85% of those achieved after bupropion immediate-release formulation administration. Exposure (AUC) to bupropion was equivalent for both formulations. Bioequivalence was also demonstrated for all three major active metabolites (i.e., hydroxybupropion, threohydrobupropion and erythrohydrobupropion) for both Cmax and AUC. Thus, at steady state, bupropion hydrochloride sustained-release tablets (SR) given twice daily, and the immediate-release formulation of bupropion given 3 times daily, are essentially bioequivalent for both bupropion and the 3 quantitatively important metabolites. Furthermore, in a study comparing 14-day dosing with bupropion hydrochloride extended-release tablets (XL), 300 mg once-daily to the immediate-release formulation of bupropion at 100 mg 3 times daily, equivalence was demonstrated for peak plasma concentration and area under the curve for bupropion and the three metabolites (hydroxybupropion, threohydrobupropion, and erythrohydrobupropion). Additionally, in a study comparing 14-day dosing with bupropion hydrochloride extended-release tablets (XL) 300 mg once daily to the sustained-release formulation of bupropion at 150 mg 2 times daily, equivalence was demonstrated for peak plasma concentration and area under the curve for bupropion and the three metabolites. Bupropion hydrochloride extended-release tablets (SR) can be taken with or without food. Bupropion Cmax and AUC were increased by 11% to 35% and 16% to 19%, respectively, when bupropion hydrochloride extended-release tablets (SR) was administered with food to healthy volunteers in three trials. The food effect is not considered clinically significant. Following a single-dose administration of bupropion hydrochloride extended-release tablets (SR) in humans, Cmax of bupropion's metabolite hydroxybupropion occurs approximately 6 hours post-dose and is approximately 10 times the peak level of the parent drug at steady state. The elimination half-life of hydroxybupropion is approximately 20 (±5) hours and its AUC at steady state is about 17 times that of bupropion. The times to peak concentrations for the erythrohydrobupropion and threohydrobupropion metabolites are similar to that of the hydroxybupropion metabolite. However, their elimination half-lives are longer, 33(±10) and 37 (±13) hours, respectively, and steady-state AUCs are 1.5 and 7 times that of bupropion, respectively. •Absorption (Drug B): The following pharmacokinetics parameters in patients with desmoid tumors were calculated as follows: C max (508 (62) ng/mL), AUC 0-tau (u 3370 (58) ng·h/mL), time to steady state (6 days), and T max (1.5 (0.5, 6.5) hours). •Volume of distribution (Drug A): No volume of distribution available •Volume of distribution (Drug B): The apparent volume of distribution [Mean (%CV)] of nirogacestat is 1430 (65) L. •Protein binding (Drug A): In vitro tests show that bupropion is 84% bound to human plasma proteins at concentrations up to 200 mcg per mL. The extent of protein binding of the hydroxybupropion metabolite is similar to that for bupropion, whereas the extent of protein binding of the threohydrobupropion metabolite is about half that seen with bupropion. •Protein binding (Drug B): Nirogacestat has a high level of serum protein binding of 99.6%, with 94.6% to serum albumin and 97.9% to alpha-1 acid glycoprotein. •Metabolism (Drug A): Bupropion is extensively metabolized in humans. Three metabolites are active: hydroxybupropion, which is formed via hydroxylation of the tert-butyl group of bupropion, and the amino-alcohol isomers, threohydrobupropion and erythrohydrobupropion, which are formed via reduction of the carbonyl group. In vitro findings suggest that CYP2B6 is the principal isoenzyme involved in the formation of hydroxybupropion, while cytochrome P450 enzymes are not involved in the formation of threohydrobupropion. Hydroxybupropion has been shown to have the same affinity as bupropion for the norepinephrine transporter (NET) but approximately 50% of its antidepressant activity despite reaching concentrations of ~10-fold higher than that of the parent drug. Oxidation of the bupropion side chain results in the formation of a glycine conjugate of meta-chlorobenzoic acid, which is then excreted as the major urinary metabolite. The potency and toxicity of the metabolites relative to bupropion have not been fully characterized. However, it has been demonstrated in an antidepressant screening test in mice that hydroxybupropion is one-half as potent as bupropion, while threohydrobupropion and erythrohydrobupropion are 5-fold less potent than bupropion. This may be of clinical importance because the plasma concentrations of the metabolites are as high as or higher than those of bupropion. Bupropion and its metabolites exhibit linear kinetics following chronic administration of 300 to 450 mg per day. •Metabolism (Drug B): Nirogacestat is expected to be metabolized primarily through the N-dealkylation via CYP3A4 (85%), with the involvement of CYP3A4, CYP2C19, CYP2C9, and CYP2D6 in a minor secondary pathway. •Route of elimination (Drug A): Bupropion is extensively metabolized in humans. Oxidation of the bupropion side chain results in the formation of a glycine conjugate of metachlorobenzoic acid, which is then excreted as the major urinary metabolite. Following oral administration of 200 mg of 14C-bupropion in humans, 87% and 10% of the radioactive dose were recovered in the urine and feces, respectively. However, the fraction of the oral dose of bupropion excreted unchanged was only 0.5%, a finding consistent with the extensive metabolism of bupropion. •Route of elimination (Drug B): Nirogacestat is excreted mostly in feces (38%) and urine 17%, with less than 1% of the unchanged drug remains in the urine. It can also be eliminated through expired air (9.7%). •Half-life (Drug A): 24 hours •Half-life (Drug B): The terminal elimination half-life [Mean (%CV)] of nirogacestat is 23 (37) hr. •Clearance (Drug A): No clearance available •Clearance (Drug B): The apparent systemic clearance [Mean (%CV)] of nirogacestat is 45 (58) L/hr. •Toxicity (Drug A): Symptoms of overdose include seizures, hallucinations, loss of consciousness, tachycardia, and cardiac arrest. •Toxicity (Drug B): Based on findings from animal studies and its mechanism of action, nirogacestat can cause fetal harm or loss of pregnancy when administered to a pregnant woman. Oral administration of nirogacestat to pregnant rats during the period of organogenesis resulted in embryo-fetal toxicity and embryo-fetal death at maternal exposures below the human exposure at the recommended dose of 150 mg twice daily. There are no available data on the use of nirogacestat in pregnant women. Advise pregnant women of the potential risk to a fetus. Due to the high level of protein binding, nirogacestat is not expected to be dialyzable. In a 6-month carcinogenicity study, transgenic rasH2 mice received up to 100 mg/kg/day of oral nirogacestat, resulting in mean exposure levels (AUC) less than those in humans at the recommended dose of 150 mg twice daily. No statistically significant neoplastic findings occurred. The carcinogenic potential of nirogacestat in rats has not been assessed. Nirogacestat was not mutagenic in a bacterial reverse mutation (Ames) assay and was not clastogenic in an in vitro chromosome aberration assay in human lymphocytes or in vivo rat bone marrow micronucleus study. Nirogacestat resulted in reduced fertility when administered to male and female rats at doses ≥ 5 mg/kg/day (approximately 0.16 times the recommended dose of 150 mg twice daily based on body surface area (BSA), and a lack of fertility when administered to male and female rats at doses ≥ 40 mg/kg/day (approximately 1.3 times the recommended dose of 150 mg twice daily based on BSA). Adverse findings in rats included ovarian atrophy, reduced testes weights, and decreased sperm concentration and motility. •Brand Names (Drug A): Aplenzin, Auvelity, Budeprion, Contrave, Forfivo, Wellbutrin, Zyban •Brand Names (Drug B): Ogsiveo •Synonyms (Drug A): No synonyms listed •Synonyms (Drug B): No synonyms listed •Summary (Drug A): Bupropion is a norepinephrine and dopamine reuptake inhibitor used in the treatment of major depressive disorder (MDD), seasonal affective disorder (SAD), and as an aid to smoking cessation. •Summary (Drug B): Nirogacestat is a gamma-secretase inhibitor used to treat desmoid tumors

The subject drug is a strong CYP2D6 inhibitor and the affected drug is metabolized by CYP2D6. Concomitant administration may decrease the metabolism of the affected drug, which could increase serum concentrations as well as the risk and severity of adverse effects. The severity of the interaction is major.

Question: Does Bupropion and Nirogacestat interact? Information: •Drug A: Bupropion •Drug B: Nirogacestat •Severity: MAJOR •Description: The metabolism of Nirogacestat can be decreased when combined with Bupropion. •Extended Description: The subject drug is a strong CYP2D6 inhibitor and the affected drug is metabolized by CYP2D6. Concomitant administration may decrease the metabolism of the affected drug, which could increase serum concentrations as well as the risk and severity of adverse effects. •Indication (Drug A): Bupropion is indicated for the treatment of major depressive disorder (MDD), seasonal affective disorder (SAD), and as an aid to smoking cessation. When used in combination with naltrexone as the marketed product ContraveⓇ, bupropion is indicated as an adjunct to a reduced-calorie diet and increased physical activity for chronic weight management in adults with an initial body mass index (BMI) of: 30 kg/m^2 or greater (obese) or 27 kg/m^2 or greater (overweight) in the presence of at least one weight-related comorbid condition (e.g., hypertension, type 2 diabetes mellitus, or dyslipidemia). Bupropion is also used off-label as a first-line treatment in patients with ADHD and comorbid bipolar disorder when used as an adjunct to mood stabilizers. •Indication (Drug B): Nirogacestat is indicated for adult patients with progressing desmoid tumors who require systemic treatment. •Pharmacodynamics (Drug A): Bupropion is chemically unrelated to tricyclic, tetracyclic, selective serotonin re-uptake inhibitors, or other known antidepressant agents. Compared to classical tricyclic antidepressants, Bupropion is a relatively weak inhibitor of the neuronal uptake of norepinephrine and dopamine. In addition, Bupropion does not inhibit monoamine oxidase. Bupropion has been found to be essentially inactive at the serotonin transporter (SERT)(IC50 >10 000 nM), however both bupropion and its primary metabolite hydroxybupropion have been found to block the function of cation-selective serotonin type 3A receptors (5-HT3ARs). Bupropion produces dose-related central nervous system (CNS) stimulant effects in animals, as evidenced by increased locomotor activity, increased rates of responding in various schedule-controlled operant behaviour tasks, and, at high doses, induction of mild stereotyped behaviour. Due to these stimulant effects and selective activity at dopamine and norepinephrine receptors, bupropion has been identified as having an abuse potential. Bupropion has a similar structure to the controlled substance Cathinone, and has been identified as having mild amphetamine-like activity, particularly when inhaled or injected. Bupropion is also known to lower the seizure threshold, making any pre-existing seizure conditions a contraindication to its use. This risk is exacerbated when bupropion is combined with other drugs or substances that lower the seizure threshold, such as cocaine, or in clinical situations that would increase the risk of a seizure such as abrupt alcohol or benzodiazepine withdrawal. As norepinephrine has been shown to have anticonvulsant properties, bupropion's inhibitory effects on NET are thought to contribute to its pro-convulsant activity. Bupropion has been shown to increase blood pressure and pose a risk for exacerbation of unmanaged or pre-existing hypertension, however, clinical trials of bupropion in smokers with CVD have not identified an increased incidence of CV events including stroke or heart attack. In clinical trials, the mean increase in systolic blood pressure associated with the use of bupropion was found to be 1.3 mmHg. •Pharmacodynamics (Drug B): There is an exposure-response relationship between nirogacestat exposure and Grade 3 hypophosphatemia with a higher risk of Grade 3 hypophosphatemia at higher exposure. At the recommended dosage, a mean increase in the QTc interval > 20 ms was not observed. •Mechanism of action (Drug A): Bupropion is a norepinephrine/dopamine-reuptake inhibitor (NDRI) that exerts its pharmacological effects by weakly inhibiting the enzymes involved in the uptake of the neurotransmitters norepinephrine and dopamine from the synaptic cleft, therefore prolonging their duration of action within the neuronal synapse and the downstream effects of these neurotransmitters. More specifically, bupropion binds to the norepinephrine transporter (NET) and the dopamine transporter (DAT). Bupropion was originally classified as an "atypical" antidepressant because it does not exert the same effects as the classical antidepressants such as Monoamine Oxidase Inhibitors (MAOIs), Tricyclic Antidepressants (TCAs), or Selective Serotonin Reuptake Inhibitors (SSRIs). While it has comparable effectiveness to typical first-line options for the treatment of depression such as SSRIs, bupropion is a unique option for the treatment of MDD as it lacks any clinically relevant serotonergic effects, typical of other mood medications, or any effects on histamine or adrenaline receptors. Lack of activity at these receptors results in a more tolerable side effect profile; bupropion is less likely to cause sexual side effects, sedation, or weight gain as compared to SSRIs or TCAs, for example. When used as an aid to smoking cessation, bupropion is thought to confer its anti-craving and anti-withdrawal effects by inhibiting dopamine reuptake, which is thought to be involved in the reward pathways associated with nicotine, and through the antagonism of the nicotinic acetylcholinergic receptor (AChR), thereby blunting the effects of nicotine. Furthermore, the stimulatory effects produced by bupropion in the central nervous system are similar to nicotine's effects, making low doses of bupropion a suitable option as a nicotine substitute. When used in combination with naltrexone in the marketed product ContraveⓇ for chronic weight management, the two components are thought to have effects on areas of the brain involved in the regulation of food intake. This includes the hypothalamus, which is involved in appetite regulation, and the mesolimbic dopamine circuit, which is involved in reward pathways. Studies have shown that the combined activity of bupropion and naltrexone increase the firing rate of hypothalamic pro-opiomelanocortin (POMC) neurons and blockade of opioid receptor-mediated POMC auto-inhibition, which are associated with a reduction in food intake and increased energy expenditure. This combination was also found to reduce food intake when injected directly into the ventral tegmental area of the mesolimbic circuit in mice, which is an area associated with the regulation of reward pathways. •Mechanism of action (Drug B): Nirogacestat is a gamma secretase inhibitor that blocks proteolytic activation of the Notch receptor. When dysregulated, Notch can activate pathways that contribute to tumor growth. •Absorption (Drug A): Bupropion is currently available in 3 distinct, but bioequivalent formulations: immediate release (IR), sustained-release (SR), and extended-release (XL). Immediate Release Formulation In humans, following oral administration of bupropion hydrochloride tablets, peak plasma bupropion concentrations are usually achieved within 2 hours. IR formulations provide a short duration of action and are therefore generally dosed three times per day. Sustained Release Formulation In humans, following oral administration of bupropion hydrochloride sustained-release tablets (SR), peak plasma concentration (Cmax) of bupropion is usually achieved within 3 hours. SR formulations provide a 12-hour extended release of medication and are therefore generally dosed twice per day. Extended Release Formulation Following single oral administration of bupropion hydrochloride extended-release tablets (XL) to healthy volunteers, the median time to peak plasma concentrations for bupropion was approximately 5 hours. The presence of food did not affect the peak concentration or area under the curve of bupropion. XL formulations provide a 24-hour extended release of medication and are therefore generally dosed once per day/ In a trial comparing chronic dosing with bupropion hydrochloride extended-release tablets (SR) 150 mg twice daily to bupropion immediate-release formulation 100 mg 3 times daily, the steady state Cmax for bupropion after bupropion hydrochloride sustained-release tablets (SR) administration was approximately 85% of those achieved after bupropion immediate-release formulation administration. Exposure (AUC) to bupropion was equivalent for both formulations. Bioequivalence was also demonstrated for all three major active metabolites (i.e., hydroxybupropion, threohydrobupropion and erythrohydrobupropion) for both Cmax and AUC. Thus, at steady state, bupropion hydrochloride sustained-release tablets (SR) given twice daily, and the immediate-release formulation of bupropion given 3 times daily, are essentially bioequivalent for both bupropion and the 3 quantitatively important metabolites. Furthermore, in a study comparing 14-day dosing with bupropion hydrochloride extended-release tablets (XL), 300 mg once-daily to the immediate-release formulation of bupropion at 100 mg 3 times daily, equivalence was demonstrated for peak plasma concentration and area under the curve for bupropion and the three metabolites (hydroxybupropion, threohydrobupropion, and erythrohydrobupropion). Additionally, in a study comparing 14-day dosing with bupropion hydrochloride extended-release tablets (XL) 300 mg once daily to the sustained-release formulation of bupropion at 150 mg 2 times daily, equivalence was demonstrated for peak plasma concentration and area under the curve for bupropion and the three metabolites. Bupropion hydrochloride extended-release tablets (SR) can be taken with or without food. Bupropion Cmax and AUC were increased by 11% to 35% and 16% to 19%, respectively, when bupropion hydrochloride extended-release tablets (SR) was administered with food to healthy volunteers in three trials. The food effect is not considered clinically significant. Following a single-dose administration of bupropion hydrochloride extended-release tablets (SR) in humans, Cmax of bupropion's metabolite hydroxybupropion occurs approximately 6 hours post-dose and is approximately 10 times the peak level of the parent drug at steady state. The elimination half-life of hydroxybupropion is approximately 20 (±5) hours and its AUC at steady state is about 17 times that of bupropion. The times to peak concentrations for the erythrohydrobupropion and threohydrobupropion metabolites are similar to that of the hydroxybupropion metabolite. However, their elimination half-lives are longer, 33(±10) and 37 (±13) hours, respectively, and steady-state AUCs are 1.5 and 7 times that of bupropion, respectively. •Absorption (Drug B): The following pharmacokinetics parameters in patients with desmoid tumors were calculated as follows: C max (508 (62) ng/mL), AUC 0-tau (u 3370 (58) ng·h/mL), time to steady state (6 days), and T max (1.5 (0.5, 6.5) hours). •Volume of distribution (Drug A): No volume of distribution available •Volume of distribution (Drug B): The apparent volume of distribution [Mean (%CV)] of nirogacestat is 1430 (65) L. •Protein binding (Drug A): In vitro tests show that bupropion is 84% bound to human plasma proteins at concentrations up to 200 mcg per mL. The extent of protein binding of the hydroxybupropion metabolite is similar to that for bupropion, whereas the extent of protein binding of the threohydrobupropion metabolite is about half that seen with bupropion. •Protein binding (Drug B): Nirogacestat has a high level of serum protein binding of 99.6%, with 94.6% to serum albumin and 97.9% to alpha-1 acid glycoprotein. •Metabolism (Drug A): Bupropion is extensively metabolized in humans. Three metabolites are active: hydroxybupropion, which is formed via hydroxylation of the tert-butyl group of bupropion, and the amino-alcohol isomers, threohydrobupropion and erythrohydrobupropion, which are formed via reduction of the carbonyl group. In vitro findings suggest that CYP2B6 is the principal isoenzyme involved in the formation of hydroxybupropion, while cytochrome P450 enzymes are not involved in the formation of threohydrobupropion. Hydroxybupropion has been shown to have the same affinity as bupropion for the norepinephrine transporter (NET) but approximately 50% of its antidepressant activity despite reaching concentrations of ~10-fold higher than that of the parent drug. Oxidation of the bupropion side chain results in the formation of a glycine conjugate of meta-chlorobenzoic acid, which is then excreted as the major urinary metabolite. The potency and toxicity of the metabolites relative to bupropion have not been fully characterized. However, it has been demonstrated in an antidepressant screening test in mice that hydroxybupropion is one-half as potent as bupropion, while threohydrobupropion and erythrohydrobupropion are 5-fold less potent than bupropion. This may be of clinical importance because the plasma concentrations of the metabolites are as high as or higher than those of bupropion. Bupropion and its metabolites exhibit linear kinetics following chronic administration of 300 to 450 mg per day. •Metabolism (Drug B): Nirogacestat is expected to be metabolized primarily through the N-dealkylation via CYP3A4 (85%), with the involvement of CYP3A4, CYP2C19, CYP2C9, and CYP2D6 in a minor secondary pathway. •Route of elimination (Drug A): Bupropion is extensively metabolized in humans. Oxidation of the bupropion side chain results in the formation of a glycine conjugate of metachlorobenzoic acid, which is then excreted as the major urinary metabolite. Following oral administration of 200 mg of 14C-bupropion in humans, 87% and 10% of the radioactive dose were recovered in the urine and feces, respectively. However, the fraction of the oral dose of bupropion excreted unchanged was only 0.5%, a finding consistent with the extensive metabolism of bupropion. •Route of elimination (Drug B): Nirogacestat is excreted mostly in feces (38%) and urine 17%, with less than 1% of the unchanged drug remains in the urine. It can also be eliminated through expired air (9.7%). •Half-life (Drug A): 24 hours •Half-life (Drug B): The terminal elimination half-life [Mean (%CV)] of nirogacestat is 23 (37) hr. •Clearance (Drug A): No clearance available •Clearance (Drug B): The apparent systemic clearance [Mean (%CV)] of nirogacestat is 45 (58) L/hr. •Toxicity (Drug A): Symptoms of overdose include seizures, hallucinations, loss of consciousness, tachycardia, and cardiac arrest. •Toxicity (Drug B): Based on findings from animal studies and its mechanism of action, nirogacestat can cause fetal harm or loss of pregnancy when administered to a pregnant woman. Oral administration of nirogacestat to pregnant rats during the period of organogenesis resulted in embryo-fetal toxicity and embryo-fetal death at maternal exposures below the human exposure at the recommended dose of 150 mg twice daily. There are no available data on the use of nirogacestat in pregnant women. Advise pregnant women of the potential risk to a fetus. Due to the high level of protein binding, nirogacestat is not expected to be dialyzable. In a 6-month carcinogenicity study, transgenic rasH2 mice received up to 100 mg/kg/day of oral nirogacestat, resulting in mean exposure levels (AUC) less than those in humans at the recommended dose of 150 mg twice daily. No statistically significant neoplastic findings occurred. The carcinogenic potential of nirogacestat in rats has not been assessed. Nirogacestat was not mutagenic in a bacterial reverse mutation (Ames) assay and was not clastogenic in an in vitro chromosome aberration assay in human lymphocytes or in vivo rat bone marrow micronucleus study. Nirogacestat resulted in reduced fertility when administered to male and female rats at doses ≥ 5 mg/kg/day (approximately 0.16 times the recommended dose of 150 mg twice daily based on body surface area (BSA), and a lack of fertility when administered to male and female rats at doses ≥ 40 mg/kg/day (approximately 1.3 times the recommended dose of 150 mg twice daily based on BSA). Adverse findings in rats included ovarian atrophy, reduced testes weights, and decreased sperm concentration and motility. •Brand Names (Drug A): Aplenzin, Auvelity, Budeprion, Contrave, Forfivo, Wellbutrin, Zyban •Brand Names (Drug B): Ogsiveo •Synonyms (Drug A): No synonyms listed •Synonyms (Drug B): No synonyms listed •Summary (Drug A): Bupropion is a norepinephrine and dopamine reuptake inhibitor used in the treatment of major depressive disorder (MDD), seasonal affective disorder (SAD), and as an aid to smoking cessation. •Summary (Drug B): Nirogacestat is a gamma-secretase inhibitor used to treat desmoid tumors Output: The subject drug is a strong CYP2D6 inhibitor and the affected drug is metabolized by CYP2D6. Concomitant administration may decrease the metabolism of the affected drug, which could increase serum concentrations as well as the risk and severity of adverse effects. The severity of the interaction is major.

Does Bupropion and Nisoldipine interact?

•Drug A: Bupropion •Drug B: Nisoldipine •Severity: MINOR •Description: Nisoldipine may decrease the excretion rate of Bupropion which could result in a higher serum level. •Extended Description: The renal excretion of drugs is the overall result of a combination of kidney processes that include glomerular filtration, passive diffusion, tubular secretion, and tubular reabsorption. Since two of these mechanisms - tubular secretion and reabsorption - are saturable processes , they are consequently susceptible to competition between multiple substrates excreted by the kidneys. If two or more medications that are mainly renally excreted are co-administered, they may compete for renal elimination; there is a large likelihood that one agent may "out-compete" or saturate the renal excretion mechanisms before the other concomitantly administered agent(s) are excreted. As a result, the elimination of these other concurrently administered agents may be inhibited or otherwise delayed, which could lead to increases in their serum concentrations and the risk, incidence, and/or severity of adverse effects associated with the exposure to such drugs. •Indication (Drug A): Bupropion is indicated for the treatment of major depressive disorder (MDD), seasonal affective disorder (SAD), and as an aid to smoking cessation. When used in combination with naltrexone as the marketed product ContraveⓇ, bupropion is indicated as an adjunct to a reduced-calorie diet and increased physical activity for chronic weight management in adults with an initial body mass index (BMI) of: 30 kg/m^2 or greater (obese) or 27 kg/m^2 or greater (overweight) in the presence of at least one weight-related comorbid condition (e.g., hypertension, type 2 diabetes mellitus, or dyslipidemia). Bupropion is also used off-label as a first-line treatment in patients with ADHD and comorbid bipolar disorder when used as an adjunct to mood stabilizers. •Indication (Drug B): For the treatment of hypertension. It may be used alone or in combination with other antihypertensive agents. •Pharmacodynamics (Drug A): Bupropion is chemically unrelated to tricyclic, tetracyclic, selective serotonin re-uptake inhibitors, or other known antidepressant agents. Compared to classical tricyclic antidepressants, Bupropion is a relatively weak inhibitor of the neuronal uptake of norepinephrine and dopamine. In addition, Bupropion does not inhibit monoamine oxidase. Bupropion has been found to be essentially inactive at the serotonin transporter (SERT)(IC50 >10 000 nM), however both bupropion and its primary metabolite hydroxybupropion have been found to block the function of cation-selective serotonin type 3A receptors (5-HT3ARs). Bupropion produces dose-related central nervous system (CNS) stimulant effects in animals, as evidenced by increased locomotor activity, increased rates of responding in various schedule-controlled operant behaviour tasks, and, at high doses, induction of mild stereotyped behaviour. Due to these stimulant effects and selective activity at dopamine and norepinephrine receptors, bupropion has been identified as having an abuse potential. Bupropion has a similar structure to the controlled substance Cathinone, and has been identified as having mild amphetamine-like activity, particularly when inhaled or injected. Bupropion is also known to lower the seizure threshold, making any pre-existing seizure conditions a contraindication to its use. This risk is exacerbated when bupropion is combined with other drugs or substances that lower the seizure threshold, such as cocaine, or in clinical situations that would increase the risk of a seizure such as abrupt alcohol or benzodiazepine withdrawal. As norepinephrine has been shown to have anticonvulsant properties, bupropion's inhibitory effects on NET are thought to contribute to its pro-convulsant activity. Bupropion has been shown to increase blood pressure and pose a risk for exacerbation of unmanaged or pre-existing hypertension, however, clinical trials of bupropion in smokers with CVD have not identified an increased incidence of CV events including stroke or heart attack. In clinical trials, the mean increase in systolic blood pressure associated with the use of bupropion was found to be 1.3 mmHg. •Pharmacodynamics (Drug B): Nisoldipine, a dihydropyridine calcium-channel blocker, is used alone or with an angiotensin-converting enzyme inhibitor, to treat hypertension, chronic stable angina pectoris, and Prinzmetal's variant angina. Nisoldipine is similar to other peripheral vasodilators. Nisoldipine inhibits the influx of extra cellular calcium across the myocardial and vascular smooth muscle cell membranes possibly by deforming the channel, inhibiting ion-control gating mechanisms, and/or interfering with the release of calcium from the sarcoplasmic reticulum. The decrease in intracellular calcium inhibits the contractile processes of the myocardial smooth muscle cells, causing dilation of the coronary and systemic arteries, increased oxygen delivery to the myocardial tissue, decreased total peripheral resistance, decreased systemic blood pressure, and decreased afterload. •Mechanism of action (Drug A): Bupropion is a norepinephrine/dopamine-reuptake inhibitor (NDRI) that exerts its pharmacological effects by weakly inhibiting the enzymes involved in the uptake of the neurotransmitters norepinephrine and dopamine from the synaptic cleft, therefore prolonging their duration of action within the neuronal synapse and the downstream effects of these neurotransmitters. More specifically, bupropion binds to the norepinephrine transporter (NET) and the dopamine transporter (DAT). Bupropion was originally classified as an "atypical" antidepressant because it does not exert the same effects as the classical antidepressants such as Monoamine Oxidase Inhibitors (MAOIs), Tricyclic Antidepressants (TCAs), or Selective Serotonin Reuptake Inhibitors (SSRIs). While it has comparable effectiveness to typical first-line options for the treatment of depression such as SSRIs, bupropion is a unique option for the treatment of MDD as it lacks any clinically relevant serotonergic effects, typical of other mood medications, or any effects on histamine or adrenaline receptors. Lack of activity at these receptors results in a more tolerable side effect profile; bupropion is less likely to cause sexual side effects, sedation, or weight gain as compared to SSRIs or TCAs, for example. When used as an aid to smoking cessation, bupropion is thought to confer its anti-craving and anti-withdrawal effects by inhibiting dopamine reuptake, which is thought to be involved in the reward pathways associated with nicotine, and through the antagonism of the nicotinic acetylcholinergic receptor (AChR), thereby blunting the effects of nicotine. Furthermore, the stimulatory effects produced by bupropion in the central nervous system are similar to nicotine's effects, making low doses of bupropion a suitable option as a nicotine substitute. When used in combination with naltrexone in the marketed product ContraveⓇ for chronic weight management, the two components are thought to have effects on areas of the brain involved in the regulation of food intake. This includes the hypothalamus, which is involved in appetite regulation, and the mesolimbic dopamine circuit, which is involved in reward pathways. Studies have shown that the combined activity of bupropion and naltrexone increase the firing rate of hypothalamic pro-opiomelanocortin (POMC) neurons and blockade of opioid receptor-mediated POMC auto-inhibition, which are associated with a reduction in food intake and increased energy expenditure. This combination was also found to reduce food intake when injected directly into the ventral tegmental area of the mesolimbic circuit in mice, which is an area associated with the regulation of reward pathways. •Mechanism of action (Drug B): By deforming the channel, inhibiting ion-control gating mechanisms, and/or interfering with the release of calcium from the sarcoplasmic reticulum, Nisoldipine inhibits the influx of extracellular calcium across the myocardial and vascular smooth muscle cell membranes The decrease in intracellular calcium inhibits the contractile processes of the myocardial smooth muscle cells, causing dilation of the coronary and systemic arteries, increased oxygen delivery to the myocardial tissue, decreased total peripheral resistance, decreased systemic blood pressure, and decreased afterload. •Absorption (Drug A): Bupropion is currently available in 3 distinct, but bioequivalent formulations: immediate release (IR), sustained-release (SR), and extended-release (XL). Immediate Release Formulation In humans, following oral administration of bupropion hydrochloride tablets, peak plasma bupropion concentrations are usually achieved within 2 hours. IR formulations provide a short duration of action and are therefore generally dosed three times per day. Sustained Release Formulation In humans, following oral administration of bupropion hydrochloride sustained-release tablets (SR), peak plasma concentration (Cmax) of bupropion is usually achieved within 3 hours. SR formulations provide a 12-hour extended release of medication and are therefore generally dosed twice per day. Extended Release Formulation Following single oral administration of bupropion hydrochloride extended-release tablets (XL) to healthy volunteers, the median time to peak plasma concentrations for bupropion was approximately 5 hours. The presence of food did not affect the peak concentration or area under the curve of bupropion. XL formulations provide a 24-hour extended release of medication and are therefore generally dosed once per day/ In a trial comparing chronic dosing with bupropion hydrochloride extended-release tablets (SR) 150 mg twice daily to bupropion immediate-release formulation 100 mg 3 times daily, the steady state Cmax for bupropion after bupropion hydrochloride sustained-release tablets (SR) administration was approximately 85% of those achieved after bupropion immediate-release formulation administration. Exposure (AUC) to bupropion was equivalent for both formulations. Bioequivalence was also demonstrated for all three major active metabolites (i.e., hydroxybupropion, threohydrobupropion and erythrohydrobupropion) for both Cmax and AUC. Thus, at steady state, bupropion hydrochloride sustained-release tablets (SR) given twice daily, and the immediate-release formulation of bupropion given 3 times daily, are essentially bioequivalent for both bupropion and the 3 quantitatively important metabolites. Furthermore, in a study comparing 14-day dosing with bupropion hydrochloride extended-release tablets (XL), 300 mg once-daily to the immediate-release formulation of bupropion at 100 mg 3 times daily, equivalence was demonstrated for peak plasma concentration and area under the curve for bupropion and the three metabolites (hydroxybupropion, threohydrobupropion, and erythrohydrobupropion). Additionally, in a study comparing 14-day dosing with bupropion hydrochloride extended-release tablets (XL) 300 mg once daily to the sustained-release formulation of bupropion at 150 mg 2 times daily, equivalence was demonstrated for peak plasma concentration and area under the curve for bupropion and the three metabolites. Bupropion hydrochloride extended-release tablets (SR) can be taken with or without food. Bupropion Cmax and AUC were increased by 11% to 35% and 16% to 19%, respectively, when bupropion hydrochloride extended-release tablets (SR) was administered with food to healthy volunteers in three trials. The food effect is not considered clinically significant. Following a single-dose administration of bupropion hydrochloride extended-release tablets (SR) in humans, Cmax of bupropion's metabolite hydroxybupropion occurs approximately 6 hours post-dose and is approximately 10 times the peak level of the parent drug at steady state. The elimination half-life of hydroxybupropion is approximately 20 (±5) hours and its AUC at steady state is about 17 times that of bupropion. The times to peak concentrations for the erythrohydrobupropion and threohydrobupropion metabolites are similar to that of the hydroxybupropion metabolite. However, their elimination half-lives are longer, 33(±10) and 37 (±13) hours, respectively, and steady-state AUCs are 1.5 and 7 times that of bupropion, respectively. •Absorption (Drug B): Relatively well absorbed into the systemic circulation with 87% of the radiolabeled drug recovered in urine and feces. The absolute bioavailability of nisoldipine is about 5%. •Volume of distribution (Drug A): No volume of distribution available •Volume of distribution (Drug B): No volume of distribution available •Protein binding (Drug A): In vitro tests show that bupropion is 84% bound to human plasma proteins at concentrations up to 200 mcg per mL. The extent of protein binding of the hydroxybupropion metabolite is similar to that for bupropion, whereas the extent of protein binding of the threohydrobupropion metabolite is about half that seen with bupropion. •Protein binding (Drug B): 99% •Metabolism (Drug A): Bupropion is extensively metabolized in humans. Three metabolites are active: hydroxybupropion, which is formed via hydroxylation of the tert-butyl group of bupropion, and the amino-alcohol isomers, threohydrobupropion and erythrohydrobupropion, which are formed via reduction of the carbonyl group. In vitro findings suggest that CYP2B6 is the principal isoenzyme involved in the formation of hydroxybupropion, while cytochrome P450 enzymes are not involved in the formation of threohydrobupropion. Hydroxybupropion has been shown to have the same affinity as bupropion for the norepinephrine transporter (NET) but approximately 50% of its antidepressant activity despite reaching concentrations of ~10-fold higher than that of the parent drug. Oxidation of the bupropion side chain results in the formation of a glycine conjugate of meta-chlorobenzoic acid, which is then excreted as the major urinary metabolite. The potency and toxicity of the metabolites relative to bupropion have not been fully characterized. However, it has been demonstrated in an antidepressant screening test in mice that hydroxybupropion is one-half as potent as bupropion, while threohydrobupropion and erythrohydrobupropion are 5-fold less potent than bupropion. This may be of clinical importance because the plasma concentrations of the metabolites are as high as or higher than those of bupropion. Bupropion and its metabolites exhibit linear kinetics following chronic administration of 300 to 450 mg per day. •Metabolism (Drug B): Pre-systemic metabolism in the gut wall, and this metabolism decreases from the proximal to the distal parts of the intestine. Nisoldipine is highly metabolized; 5 major urinary metabolites have been identified. The major biotransformation pathway appears to be the hydroxylation of the isobutyl ester. A hydroxylated derivative of the side chain, present in plasma at concentrations approximately equal to the parent compound, appears to be the only active metabolite and has about 10% of the activity of the parent compound. Cytochrome P450 enzymes are believed to play a major role in the metabolism of nisoldipine. The particular isoenzyme system responsible for its metabolism has not been identified, but other dihydropyridines are metabolized by cytochrome P450 IIIA4. •Route of elimination (Drug A): Bupropion is extensively metabolized in humans. Oxidation of the bupropion side chain results in the formation of a glycine conjugate of metachlorobenzoic acid, which is then excreted as the major urinary metabolite. Following oral administration of 200 mg of 14C-bupropion in humans, 87% and 10% of the radioactive dose were recovered in the urine and feces, respectively. However, the fraction of the oral dose of bupropion excreted unchanged was only 0.5%, a finding consistent with the extensive metabolism of bupropion. •Route of elimination (Drug B): Although 60-80% of an oral dose undergoes urinary excretion, only traces of unchanged nisoldipine are found in urine. •Half-life (Drug A): 24 hours •Half-life (Drug B): 7-12 hours •Clearance (Drug A): No clearance available •Clearance (Drug B): No clearance available •Toxicity (Drug A): Symptoms of overdose include seizures, hallucinations, loss of consciousness, tachycardia, and cardiac arrest. •Toxicity (Drug B): No toxicity available •Brand Names (Drug A): Aplenzin, Auvelity, Budeprion, Contrave, Forfivo, Wellbutrin, Zyban •Brand Names (Drug B): Sular •Synonyms (Drug A): No synonyms listed •Synonyms (Drug B): Nisoldipin Nisoldipina Nisoldipine Nisoldipino Nisoldipinum •Summary (Drug A): Bupropion is a norepinephrine and dopamine reuptake inhibitor used in the treatment of major depressive disorder (MDD), seasonal affective disorder (SAD), and as an aid to smoking cessation. •Summary (Drug B): Nisoldipine is a calcium channel blocker used as monotherapy or combined with other drugs for the treatment of hypertension.

The renal excretion of drugs is the overall result of a combination of kidney processes that include glomerular filtration, passive diffusion, tubular secretion, and tubular reabsorption. Since two of these mechanisms - tubular secretion and reabsorption - are saturable processes , they are consequently susceptible to competition between multiple substrates excreted by the kidneys. If two or more medications that are mainly renally excreted are co-administered, they may compete for renal elimination; there is a large likelihood that one agent may "out-compete" or saturate the renal excretion mechanisms before the other concomitantly administered agent(s) are excreted. As a result, the elimination of these other concurrently administered agents may be inhibited or otherwise delayed, which could lead to increases in their serum concentrations and the risk, incidence, and/or severity of adverse effects associated with the exposure to such drugs. The severity of the interaction is minor.

Question: Does Bupropion and Nisoldipine interact? Information: •Drug A: Bupropion •Drug B: Nisoldipine •Severity: MINOR •Description: Nisoldipine may decrease the excretion rate of Bupropion which could result in a higher serum level. •Extended Description: The renal excretion of drugs is the overall result of a combination of kidney processes that include glomerular filtration, passive diffusion, tubular secretion, and tubular reabsorption. Since two of these mechanisms - tubular secretion and reabsorption - are saturable processes , they are consequently susceptible to competition between multiple substrates excreted by the kidneys. If two or more medications that are mainly renally excreted are co-administered, they may compete for renal elimination; there is a large likelihood that one agent may "out-compete" or saturate the renal excretion mechanisms before the other concomitantly administered agent(s) are excreted. As a result, the elimination of these other concurrently administered agents may be inhibited or otherwise delayed, which could lead to increases in their serum concentrations and the risk, incidence, and/or severity of adverse effects associated with the exposure to such drugs. •Indication (Drug A): Bupropion is indicated for the treatment of major depressive disorder (MDD), seasonal affective disorder (SAD), and as an aid to smoking cessation. When used in combination with naltrexone as the marketed product ContraveⓇ, bupropion is indicated as an adjunct to a reduced-calorie diet and increased physical activity for chronic weight management in adults with an initial body mass index (BMI) of: 30 kg/m^2 or greater (obese) or 27 kg/m^2 or greater (overweight) in the presence of at least one weight-related comorbid condition (e.g., hypertension, type 2 diabetes mellitus, or dyslipidemia). Bupropion is also used off-label as a first-line treatment in patients with ADHD and comorbid bipolar disorder when used as an adjunct to mood stabilizers. •Indication (Drug B): For the treatment of hypertension. It may be used alone or in combination with other antihypertensive agents. •Pharmacodynamics (Drug A): Bupropion is chemically unrelated to tricyclic, tetracyclic, selective serotonin re-uptake inhibitors, or other known antidepressant agents. Compared to classical tricyclic antidepressants, Bupropion is a relatively weak inhibitor of the neuronal uptake of norepinephrine and dopamine. In addition, Bupropion does not inhibit monoamine oxidase. Bupropion has been found to be essentially inactive at the serotonin transporter (SERT)(IC50 >10 000 nM), however both bupropion and its primary metabolite hydroxybupropion have been found to block the function of cation-selective serotonin type 3A receptors (5-HT3ARs). Bupropion produces dose-related central nervous system (CNS) stimulant effects in animals, as evidenced by increased locomotor activity, increased rates of responding in various schedule-controlled operant behaviour tasks, and, at high doses, induction of mild stereotyped behaviour. Due to these stimulant effects and selective activity at dopamine and norepinephrine receptors, bupropion has been identified as having an abuse potential. Bupropion has a similar structure to the controlled substance Cathinone, and has been identified as having mild amphetamine-like activity, particularly when inhaled or injected. Bupropion is also known to lower the seizure threshold, making any pre-existing seizure conditions a contraindication to its use. This risk is exacerbated when bupropion is combined with other drugs or substances that lower the seizure threshold, such as cocaine, or in clinical situations that would increase the risk of a seizure such as abrupt alcohol or benzodiazepine withdrawal. As norepinephrine has been shown to have anticonvulsant properties, bupropion's inhibitory effects on NET are thought to contribute to its pro-convulsant activity. Bupropion has been shown to increase blood pressure and pose a risk for exacerbation of unmanaged or pre-existing hypertension, however, clinical trials of bupropion in smokers with CVD have not identified an increased incidence of CV events including stroke or heart attack. In clinical trials, the mean increase in systolic blood pressure associated with the use of bupropion was found to be 1.3 mmHg. •Pharmacodynamics (Drug B): Nisoldipine, a dihydropyridine calcium-channel blocker, is used alone or with an angiotensin-converting enzyme inhibitor, to treat hypertension, chronic stable angina pectoris, and Prinzmetal's variant angina. Nisoldipine is similar to other peripheral vasodilators. Nisoldipine inhibits the influx of extra cellular calcium across the myocardial and vascular smooth muscle cell membranes possibly by deforming the channel, inhibiting ion-control gating mechanisms, and/or interfering with the release of calcium from the sarcoplasmic reticulum. The decrease in intracellular calcium inhibits the contractile processes of the myocardial smooth muscle cells, causing dilation of the coronary and systemic arteries, increased oxygen delivery to the myocardial tissue, decreased total peripheral resistance, decreased systemic blood pressure, and decreased afterload. •Mechanism of action (Drug A): Bupropion is a norepinephrine/dopamine-reuptake inhibitor (NDRI) that exerts its pharmacological effects by weakly inhibiting the enzymes involved in the uptake of the neurotransmitters norepinephrine and dopamine from the synaptic cleft, therefore prolonging their duration of action within the neuronal synapse and the downstream effects of these neurotransmitters. More specifically, bupropion binds to the norepinephrine transporter (NET) and the dopamine transporter (DAT). Bupropion was originally classified as an "atypical" antidepressant because it does not exert the same effects as the classical antidepressants such as Monoamine Oxidase Inhibitors (MAOIs), Tricyclic Antidepressants (TCAs), or Selective Serotonin Reuptake Inhibitors (SSRIs). While it has comparable effectiveness to typical first-line options for the treatment of depression such as SSRIs, bupropion is a unique option for the treatment of MDD as it lacks any clinically relevant serotonergic effects, typical of other mood medications, or any effects on histamine or adrenaline receptors. Lack of activity at these receptors results in a more tolerable side effect profile; bupropion is less likely to cause sexual side effects, sedation, or weight gain as compared to SSRIs or TCAs, for example. When used as an aid to smoking cessation, bupropion is thought to confer its anti-craving and anti-withdrawal effects by inhibiting dopamine reuptake, which is thought to be involved in the reward pathways associated with nicotine, and through the antagonism of the nicotinic acetylcholinergic receptor (AChR), thereby blunting the effects of nicotine. Furthermore, the stimulatory effects produced by bupropion in the central nervous system are similar to nicotine's effects, making low doses of bupropion a suitable option as a nicotine substitute. When used in combination with naltrexone in the marketed product ContraveⓇ for chronic weight management, the two components are thought to have effects on areas of the brain involved in the regulation of food intake. This includes the hypothalamus, which is involved in appetite regulation, and the mesolimbic dopamine circuit, which is involved in reward pathways. Studies have shown that the combined activity of bupropion and naltrexone increase the firing rate of hypothalamic pro-opiomelanocortin (POMC) neurons and blockade of opioid receptor-mediated POMC auto-inhibition, which are associated with a reduction in food intake and increased energy expenditure. This combination was also found to reduce food intake when injected directly into the ventral tegmental area of the mesolimbic circuit in mice, which is an area associated with the regulation of reward pathways. •Mechanism of action (Drug B): By deforming the channel, inhibiting ion-control gating mechanisms, and/or interfering with the release of calcium from the sarcoplasmic reticulum, Nisoldipine inhibits the influx of extracellular calcium across the myocardial and vascular smooth muscle cell membranes The decrease in intracellular calcium inhibits the contractile processes of the myocardial smooth muscle cells, causing dilation of the coronary and systemic arteries, increased oxygen delivery to the myocardial tissue, decreased total peripheral resistance, decreased systemic blood pressure, and decreased afterload. •Absorption (Drug A): Bupropion is currently available in 3 distinct, but bioequivalent formulations: immediate release (IR), sustained-release (SR), and extended-release (XL). Immediate Release Formulation In humans, following oral administration of bupropion hydrochloride tablets, peak plasma bupropion concentrations are usually achieved within 2 hours. IR formulations provide a short duration of action and are therefore generally dosed three times per day. Sustained Release Formulation In humans, following oral administration of bupropion hydrochloride sustained-release tablets (SR), peak plasma concentration (Cmax) of bupropion is usually achieved within 3 hours. SR formulations provide a 12-hour extended release of medication and are therefore generally dosed twice per day. Extended Release Formulation Following single oral administration of bupropion hydrochloride extended-release tablets (XL) to healthy volunteers, the median time to peak plasma concentrations for bupropion was approximately 5 hours. The presence of food did not affect the peak concentration or area under the curve of bupropion. XL formulations provide a 24-hour extended release of medication and are therefore generally dosed once per day/ In a trial comparing chronic dosing with bupropion hydrochloride extended-release tablets (SR) 150 mg twice daily to bupropion immediate-release formulation 100 mg 3 times daily, the steady state Cmax for bupropion after bupropion hydrochloride sustained-release tablets (SR) administration was approximately 85% of those achieved after bupropion immediate-release formulation administration. Exposure (AUC) to bupropion was equivalent for both formulations. Bioequivalence was also demonstrated for all three major active metabolites (i.e., hydroxybupropion, threohydrobupropion and erythrohydrobupropion) for both Cmax and AUC. Thus, at steady state, bupropion hydrochloride sustained-release tablets (SR) given twice daily, and the immediate-release formulation of bupropion given 3 times daily, are essentially bioequivalent for both bupropion and the 3 quantitatively important metabolites. Furthermore, in a study comparing 14-day dosing with bupropion hydrochloride extended-release tablets (XL), 300 mg once-daily to the immediate-release formulation of bupropion at 100 mg 3 times daily, equivalence was demonstrated for peak plasma concentration and area under the curve for bupropion and the three metabolites (hydroxybupropion, threohydrobupropion, and erythrohydrobupropion). Additionally, in a study comparing 14-day dosing with bupropion hydrochloride extended-release tablets (XL) 300 mg once daily to the sustained-release formulation of bupropion at 150 mg 2 times daily, equivalence was demonstrated for peak plasma concentration and area under the curve for bupropion and the three metabolites. Bupropion hydrochloride extended-release tablets (SR) can be taken with or without food. Bupropion Cmax and AUC were increased by 11% to 35% and 16% to 19%, respectively, when bupropion hydrochloride extended-release tablets (SR) was administered with food to healthy volunteers in three trials. The food effect is not considered clinically significant. Following a single-dose administration of bupropion hydrochloride extended-release tablets (SR) in humans, Cmax of bupropion's metabolite hydroxybupropion occurs approximately 6 hours post-dose and is approximately 10 times the peak level of the parent drug at steady state. The elimination half-life of hydroxybupropion is approximately 20 (±5) hours and its AUC at steady state is about 17 times that of bupropion. The times to peak concentrations for the erythrohydrobupropion and threohydrobupropion metabolites are similar to that of the hydroxybupropion metabolite. However, their elimination half-lives are longer, 33(±10) and 37 (±13) hours, respectively, and steady-state AUCs are 1.5 and 7 times that of bupropion, respectively. •Absorption (Drug B): Relatively well absorbed into the systemic circulation with 87% of the radiolabeled drug recovered in urine and feces. The absolute bioavailability of nisoldipine is about 5%. •Volume of distribution (Drug A): No volume of distribution available •Volume of distribution (Drug B): No volume of distribution available •Protein binding (Drug A): In vitro tests show that bupropion is 84% bound to human plasma proteins at concentrations up to 200 mcg per mL. The extent of protein binding of the hydroxybupropion metabolite is similar to that for bupropion, whereas the extent of protein binding of the threohydrobupropion metabolite is about half that seen with bupropion. •Protein binding (Drug B): 99% •Metabolism (Drug A): Bupropion is extensively metabolized in humans. Three metabolites are active: hydroxybupropion, which is formed via hydroxylation of the tert-butyl group of bupropion, and the amino-alcohol isomers, threohydrobupropion and erythrohydrobupropion, which are formed via reduction of the carbonyl group. In vitro findings suggest that CYP2B6 is the principal isoenzyme involved in the formation of hydroxybupropion, while cytochrome P450 enzymes are not involved in the formation of threohydrobupropion. Hydroxybupropion has been shown to have the same affinity as bupropion for the norepinephrine transporter (NET) but approximately 50% of its antidepressant activity despite reaching concentrations of ~10-fold higher than that of the parent drug. Oxidation of the bupropion side chain results in the formation of a glycine conjugate of meta-chlorobenzoic acid, which is then excreted as the major urinary metabolite. The potency and toxicity of the metabolites relative to bupropion have not been fully characterized. However, it has been demonstrated in an antidepressant screening test in mice that hydroxybupropion is one-half as potent as bupropion, while threohydrobupropion and erythrohydrobupropion are 5-fold less potent than bupropion. This may be of clinical importance because the plasma concentrations of the metabolites are as high as or higher than those of bupropion. Bupropion and its metabolites exhibit linear kinetics following chronic administration of 300 to 450 mg per day. •Metabolism (Drug B): Pre-systemic metabolism in the gut wall, and this metabolism decreases from the proximal to the distal parts of the intestine. Nisoldipine is highly metabolized; 5 major urinary metabolites have been identified. The major biotransformation pathway appears to be the hydroxylation of the isobutyl ester. A hydroxylated derivative of the side chain, present in plasma at concentrations approximately equal to the parent compound, appears to be the only active metabolite and has about 10% of the activity of the parent compound. Cytochrome P450 enzymes are believed to play a major role in the metabolism of nisoldipine. The particular isoenzyme system responsible for its metabolism has not been identified, but other dihydropyridines are metabolized by cytochrome P450 IIIA4. •Route of elimination (Drug A): Bupropion is extensively metabolized in humans. Oxidation of the bupropion side chain results in the formation of a glycine conjugate of metachlorobenzoic acid, which is then excreted as the major urinary metabolite. Following oral administration of 200 mg of 14C-bupropion in humans, 87% and 10% of the radioactive dose were recovered in the urine and feces, respectively. However, the fraction of the oral dose of bupropion excreted unchanged was only 0.5%, a finding consistent with the extensive metabolism of bupropion. •Route of elimination (Drug B): Although 60-80% of an oral dose undergoes urinary excretion, only traces of unchanged nisoldipine are found in urine. •Half-life (Drug A): 24 hours •Half-life (Drug B): 7-12 hours •Clearance (Drug A): No clearance available •Clearance (Drug B): No clearance available •Toxicity (Drug A): Symptoms of overdose include seizures, hallucinations, loss of consciousness, tachycardia, and cardiac arrest. •Toxicity (Drug B): No toxicity available •Brand Names (Drug A): Aplenzin, Auvelity, Budeprion, Contrave, Forfivo, Wellbutrin, Zyban •Brand Names (Drug B): Sular •Synonyms (Drug A): No synonyms listed •Synonyms (Drug B): Nisoldipin Nisoldipina Nisoldipine Nisoldipino Nisoldipinum •Summary (Drug A): Bupropion is a norepinephrine and dopamine reuptake inhibitor used in the treatment of major depressive disorder (MDD), seasonal affective disorder (SAD), and as an aid to smoking cessation. •Summary (Drug B): Nisoldipine is a calcium channel blocker used as monotherapy or combined with other drugs for the treatment of hypertension. Output: The renal excretion of drugs is the overall result of a combination of kidney processes that include glomerular filtration, passive diffusion, tubular secretion, and tubular reabsorption. Since two of these mechanisms - tubular secretion and reabsorption - are saturable processes , they are consequently susceptible to competition between multiple substrates excreted by the kidneys. If two or more medications that are mainly renally excreted are co-administered, they may compete for renal elimination; there is a large likelihood that one agent may "out-compete" or saturate the renal excretion mechanisms before the other concomitantly administered agent(s) are excreted. As a result, the elimination of these other concurrently administered agents may be inhibited or otherwise delayed, which could lead to increases in their serum concentrations and the risk, incidence, and/or severity of adverse effects associated with the exposure to such drugs. The severity of the interaction is minor.

Does Bupropion and Nitrazepam interact?

•Drug A: Bupropion •Drug B: Nitrazepam •Severity: MODERATE •Description: The risk or severity of CNS depression can be increased when Bupropion is combined with Nitrazepam. •Extended Description: Central nervous system (CNS) depressants can cause sedation, falls, respiratory depression, coma, and death.2,3 The potential interaction between a CNS depressant and another CNS depressant drug due to synergistic effects is well documented in the literature, although the risk and severity of CNS depression vary from each drug. The subject and affected drugs are both CNS depressants that, when co-administered, may result in a more profound CNS depression. As the risk and severity of CNS depression resulting from the combined use of CNS depressants vary from each agent, each interaction between CNS depressants should be considered individually. •Indication (Drug A): Bupropion is indicated for the treatment of major depressive disorder (MDD), seasonal affective disorder (SAD), and as an aid to smoking cessation. When used in combination with naltrexone as the marketed product ContraveⓇ, bupropion is indicated as an adjunct to a reduced-calorie diet and increased physical activity for chronic weight management in adults with an initial body mass index (BMI) of: 30 kg/m^2 or greater (obese) or 27 kg/m^2 or greater (overweight) in the presence of at least one weight-related comorbid condition (e.g., hypertension, type 2 diabetes mellitus, or dyslipidemia). Bupropion is also used off-label as a first-line treatment in patients with ADHD and comorbid bipolar disorder when used as an adjunct to mood stabilizers. •Indication (Drug B): Used to treat short-term sleeping problems (insomnia), such as difficulty falling asleep, frequent awakenings during the night, and early-morning awakening. •Pharmacodynamics (Drug A): Bupropion is chemically unrelated to tricyclic, tetracyclic, selective serotonin re-uptake inhibitors, or other known antidepressant agents. Compared to classical tricyclic antidepressants, Bupropion is a relatively weak inhibitor of the neuronal uptake of norepinephrine and dopamine. In addition, Bupropion does not inhibit monoamine oxidase. Bupropion has been found to be essentially inactive at the serotonin transporter (SERT)(IC50 >10 000 nM), however both bupropion and its primary metabolite hydroxybupropion have been found to block the function of cation-selective serotonin type 3A receptors (5-HT3ARs). Bupropion produces dose-related central nervous system (CNS) stimulant effects in animals, as evidenced by increased locomotor activity, increased rates of responding in various schedule-controlled operant behaviour tasks, and, at high doses, induction of mild stereotyped behaviour. Due to these stimulant effects and selective activity at dopamine and norepinephrine receptors, bupropion has been identified as having an abuse potential. Bupropion has a similar structure to the controlled substance Cathinone, and has been identified as having mild amphetamine-like activity, particularly when inhaled or injected. Bupropion is also known to lower the seizure threshold, making any pre-existing seizure conditions a contraindication to its use. This risk is exacerbated when bupropion is combined with other drugs or substances that lower the seizure threshold, such as cocaine, or in clinical situations that would increase the risk of a seizure such as abrupt alcohol or benzodiazepine withdrawal. As norepinephrine has been shown to have anticonvulsant properties, bupropion's inhibitory effects on NET are thought to contribute to its pro-convulsant activity. Bupropion has been shown to increase blood pressure and pose a risk for exacerbation of unmanaged or pre-existing hypertension, however, clinical trials of bupropion in smokers with CVD have not identified an increased incidence of CV events including stroke or heart attack. In clinical trials, the mean increase in systolic blood pressure associated with the use of bupropion was found to be 1.3 mmHg. •Pharmacodynamics (Drug B): Nitrazepam is a type of benzodiazepine drug. It is a powerful hypnotic drug which possesses strong sedative, anxiolytic, amnestic, anticonvulsant, and skeletal muscle relaxant properties. Nitrazepam shortens the time required to fall asleep and lengthens the duration of sleep. It is also useful for the management of myoclonic seizures. •Mechanism of action (Drug A): Bupropion is a norepinephrine/dopamine-reuptake inhibitor (NDRI) that exerts its pharmacological effects by weakly inhibiting the enzymes involved in the uptake of the neurotransmitters norepinephrine and dopamine from the synaptic cleft, therefore prolonging their duration of action within the neuronal synapse and the downstream effects of these neurotransmitters. More specifically, bupropion binds to the norepinephrine transporter (NET) and the dopamine transporter (DAT). Bupropion was originally classified as an "atypical" antidepressant because it does not exert the same effects as the classical antidepressants such as Monoamine Oxidase Inhibitors (MAOIs), Tricyclic Antidepressants (TCAs), or Selective Serotonin Reuptake Inhibitors (SSRIs). While it has comparable effectiveness to typical first-line options for the treatment of depression such as SSRIs, bupropion is a unique option for the treatment of MDD as it lacks any clinically relevant serotonergic effects, typical of other mood medications, or any effects on histamine or adrenaline receptors. Lack of activity at these receptors results in a more tolerable side effect profile; bupropion is less likely to cause sexual side effects, sedation, or weight gain as compared to SSRIs or TCAs, for example. When used as an aid to smoking cessation, bupropion is thought to confer its anti-craving and anti-withdrawal effects by inhibiting dopamine reuptake, which is thought to be involved in the reward pathways associated with nicotine, and through the antagonism of the nicotinic acetylcholinergic receptor (AChR), thereby blunting the effects of nicotine. Furthermore, the stimulatory effects produced by bupropion in the central nervous system are similar to nicotine's effects, making low doses of bupropion a suitable option as a nicotine substitute. When used in combination with naltrexone in the marketed product ContraveⓇ for chronic weight management, the two components are thought to have effects on areas of the brain involved in the regulation of food intake. This includes the hypothalamus, which is involved in appetite regulation, and the mesolimbic dopamine circuit, which is involved in reward pathways. Studies have shown that the combined activity of bupropion and naltrexone increase the firing rate of hypothalamic pro-opiomelanocortin (POMC) neurons and blockade of opioid receptor-mediated POMC auto-inhibition, which are associated with a reduction in food intake and increased energy expenditure. This combination was also found to reduce food intake when injected directly into the ventral tegmental area of the mesolimbic circuit in mice, which is an area associated with the regulation of reward pathways. •Mechanism of action (Drug B): Nitrazepam belongs to a group of medicines called benzodiazepines. This drug affects central benzodiazepine receptors, which are associated with inhibitory GABA (gamma amino butyric acid)receptors, leading to enhanced GABA binding activity. GABA is a major neurotransmitter in the brain, which causes somnolence, relaxation of muscles, a decrease in anxiety and general central nervous system depression. Nitrazepam has anticonvulsant properties that may be attributed to its ability to bind to voltage-dependent sodium channels. Sustained repetitive firing seems to be limited by benzodiazepines effect of slowing recovery of sodium channels from inactivation. •Absorption (Drug A): Bupropion is currently available in 3 distinct, but bioequivalent formulations: immediate release (IR), sustained-release (SR), and extended-release (XL). Immediate Release Formulation In humans, following oral administration of bupropion hydrochloride tablets, peak plasma bupropion concentrations are usually achieved within 2 hours. IR formulations provide a short duration of action and are therefore generally dosed three times per day. Sustained Release Formulation In humans, following oral administration of bupropion hydrochloride sustained-release tablets (SR), peak plasma concentration (Cmax) of bupropion is usually achieved within 3 hours. SR formulations provide a 12-hour extended release of medication and are therefore generally dosed twice per day. Extended Release Formulation Following single oral administration of bupropion hydrochloride extended-release tablets (XL) to healthy volunteers, the median time to peak plasma concentrations for bupropion was approximately 5 hours. The presence of food did not affect the peak concentration or area under the curve of bupropion. XL formulations provide a 24-hour extended release of medication and are therefore generally dosed once per day/ In a trial comparing chronic dosing with bupropion hydrochloride extended-release tablets (SR) 150 mg twice daily to bupropion immediate-release formulation 100 mg 3 times daily, the steady state Cmax for bupropion after bupropion hydrochloride sustained-release tablets (SR) administration was approximately 85% of those achieved after bupropion immediate-release formulation administration. Exposure (AUC) to bupropion was equivalent for both formulations. Bioequivalence was also demonstrated for all three major active metabolites (i.e., hydroxybupropion, threohydrobupropion and erythrohydrobupropion) for both Cmax and AUC. Thus, at steady state, bupropion hydrochloride sustained-release tablets (SR) given twice daily, and the immediate-release formulation of bupropion given 3 times daily, are essentially bioequivalent for both bupropion and the 3 quantitatively important metabolites. Furthermore, in a study comparing 14-day dosing with bupropion hydrochloride extended-release tablets (XL), 300 mg once-daily to the immediate-release formulation of bupropion at 100 mg 3 times daily, equivalence was demonstrated for peak plasma concentration and area under the curve for bupropion and the three metabolites (hydroxybupropion, threohydrobupropion, and erythrohydrobupropion). Additionally, in a study comparing 14-day dosing with bupropion hydrochloride extended-release tablets (XL) 300 mg once daily to the sustained-release formulation of bupropion at 150 mg 2 times daily, equivalence was demonstrated for peak plasma concentration and area under the curve for bupropion and the three metabolites. Bupropion hydrochloride extended-release tablets (SR) can be taken with or without food. Bupropion Cmax and AUC were increased by 11% to 35% and 16% to 19%, respectively, when bupropion hydrochloride extended-release tablets (SR) was administered with food to healthy volunteers in three trials. The food effect is not considered clinically significant. Following a single-dose administration of bupropion hydrochloride extended-release tablets (SR) in humans, Cmax of bupropion's metabolite hydroxybupropion occurs approximately 6 hours post-dose and is approximately 10 times the peak level of the parent drug at steady state. The elimination half-life of hydroxybupropion is approximately 20 (±5) hours and its AUC at steady state is about 17 times that of bupropion. The times to peak concentrations for the erythrohydrobupropion and threohydrobupropion metabolites are similar to that of the hydroxybupropion metabolite. However, their elimination half-lives are longer, 33(±10) and 37 (±13) hours, respectively, and steady-state AUCs are 1.5 and 7 times that of bupropion, respectively. •Absorption (Drug B): Bioavailability is 53-94% following oral administration. •Volume of distribution (Drug A): No volume of distribution available •Volume of distribution (Drug B): No volume of distribution available •Protein binding (Drug A): In vitro tests show that bupropion is 84% bound to human plasma proteins at concentrations up to 200 mcg per mL. The extent of protein binding of the hydroxybupropion metabolite is similar to that for bupropion, whereas the extent of protein binding of the threohydrobupropion metabolite is about half that seen with bupropion. •Protein binding (Drug B): No protein binding available •Metabolism (Drug A): Bupropion is extensively metabolized in humans. Three metabolites are active: hydroxybupropion, which is formed via hydroxylation of the tert-butyl group of bupropion, and the amino-alcohol isomers, threohydrobupropion and erythrohydrobupropion, which are formed via reduction of the carbonyl group. In vitro findings suggest that CYP2B6 is the principal isoenzyme involved in the formation of hydroxybupropion, while cytochrome P450 enzymes are not involved in the formation of threohydrobupropion. Hydroxybupropion has been shown to have the same affinity as bupropion for the norepinephrine transporter (NET) but approximately 50% of its antidepressant activity despite reaching concentrations of ~10-fold higher than that of the parent drug. Oxidation of the bupropion side chain results in the formation of a glycine conjugate of meta-chlorobenzoic acid, which is then excreted as the major urinary metabolite. The potency and toxicity of the metabolites relative to bupropion have not been fully characterized. However, it has been demonstrated in an antidepressant screening test in mice that hydroxybupropion is one-half as potent as bupropion, while threohydrobupropion and erythrohydrobupropion are 5-fold less potent than bupropion. This may be of clinical importance because the plasma concentrations of the metabolites are as high as or higher than those of bupropion. Bupropion and its metabolites exhibit linear kinetics following chronic administration of 300 to 450 mg per day. •Metabolism (Drug B): No metabolism available •Route of elimination (Drug A): Bupropion is extensively metabolized in humans. Oxidation of the bupropion side chain results in the formation of a glycine conjugate of metachlorobenzoic acid, which is then excreted as the major urinary metabolite. Following oral administration of 200 mg of 14C-bupropion in humans, 87% and 10% of the radioactive dose were recovered in the urine and feces, respectively. However, the fraction of the oral dose of bupropion excreted unchanged was only 0.5%, a finding consistent with the extensive metabolism of bupropion. •Route of elimination (Drug B): No route of elimination available •Half-life (Drug A): 24 hours •Half-life (Drug B): 15-38 hours (mean elimination half life 26 hours). •Clearance (Drug A): No clearance available •Clearance (Drug B): No clearance available •Toxicity (Drug A): Symptoms of overdose include seizures, hallucinations, loss of consciousness, tachycardia, and cardiac arrest. •Toxicity (Drug B): An overdose of nitrazepam may lead to impaired breathing, dizziness, decreased cognition and balance, bluish nails and lips, slurred speech, and extreme somnolence, among others. In severe overdose, these symptoms may progress to a coma with a possibility of death. •Brand Names (Drug A): Aplenzin, Auvelity, Budeprion, Contrave, Forfivo, Wellbutrin, Zyban •Brand Names (Drug B): Mogadon •Synonyms (Drug A): No synonyms listed •Synonyms (Drug B): N-desmethylnimetazepam Nitrazepam Nitrazépam Nitrazepamum •Summary (Drug A): Bupropion is a norepinephrine and dopamine reuptake inhibitor used in the treatment of major depressive disorder (MDD), seasonal affective disorder (SAD), and as an aid to smoking cessation. •Summary (Drug B): Nitrazepam is a long-acting benzodiazepine with intermediate onset commonly used to treat panic disorders, severe anxiety, insomnia, and seizures.

Central nervous system (CNS) depressants can cause sedation, falls, respiratory depression, coma, and death.2,3 The potential interaction between a CNS depressant and another CNS depressant drug due to synergistic effects is well documented in the literature, although the risk and severity of CNS depression vary from each drug. The subject and affected drugs are both CNS depressants that, when co-administered, may result in a more profound CNS depression. As the risk and severity of CNS depression resulting from the combined use of CNS depressants vary from each agent, each interaction between CNS depressants should be considered individually. The severity of the interaction is moderate.

Question: Does Bupropion and Nitrazepam interact? Information: •Drug A: Bupropion •Drug B: Nitrazepam •Severity: MODERATE •Description: The risk or severity of CNS depression can be increased when Bupropion is combined with Nitrazepam. •Extended Description: Central nervous system (CNS) depressants can cause sedation, falls, respiratory depression, coma, and death.2,3 The potential interaction between a CNS depressant and another CNS depressant drug due to synergistic effects is well documented in the literature, although the risk and severity of CNS depression vary from each drug. The subject and affected drugs are both CNS depressants that, when co-administered, may result in a more profound CNS depression. As the risk and severity of CNS depression resulting from the combined use of CNS depressants vary from each agent, each interaction between CNS depressants should be considered individually. •Indication (Drug A): Bupropion is indicated for the treatment of major depressive disorder (MDD), seasonal affective disorder (SAD), and as an aid to smoking cessation. When used in combination with naltrexone as the marketed product ContraveⓇ, bupropion is indicated as an adjunct to a reduced-calorie diet and increased physical activity for chronic weight management in adults with an initial body mass index (BMI) of: 30 kg/m^2 or greater (obese) or 27 kg/m^2 or greater (overweight) in the presence of at least one weight-related comorbid condition (e.g., hypertension, type 2 diabetes mellitus, or dyslipidemia). Bupropion is also used off-label as a first-line treatment in patients with ADHD and comorbid bipolar disorder when used as an adjunct to mood stabilizers. •Indication (Drug B): Used to treat short-term sleeping problems (insomnia), such as difficulty falling asleep, frequent awakenings during the night, and early-morning awakening. •Pharmacodynamics (Drug A): Bupropion is chemically unrelated to tricyclic, tetracyclic, selective serotonin re-uptake inhibitors, or other known antidepressant agents. Compared to classical tricyclic antidepressants, Bupropion is a relatively weak inhibitor of the neuronal uptake of norepinephrine and dopamine. In addition, Bupropion does not inhibit monoamine oxidase. Bupropion has been found to be essentially inactive at the serotonin transporter (SERT)(IC50 >10 000 nM), however both bupropion and its primary metabolite hydroxybupropion have been found to block the function of cation-selective serotonin type 3A receptors (5-HT3ARs). Bupropion produces dose-related central nervous system (CNS) stimulant effects in animals, as evidenced by increased locomotor activity, increased rates of responding in various schedule-controlled operant behaviour tasks, and, at high doses, induction of mild stereotyped behaviour. Due to these stimulant effects and selective activity at dopamine and norepinephrine receptors, bupropion has been identified as having an abuse potential. Bupropion has a similar structure to the controlled substance Cathinone, and has been identified as having mild amphetamine-like activity, particularly when inhaled or injected. Bupropion is also known to lower the seizure threshold, making any pre-existing seizure conditions a contraindication to its use. This risk is exacerbated when bupropion is combined with other drugs or substances that lower the seizure threshold, such as cocaine, or in clinical situations that would increase the risk of a seizure such as abrupt alcohol or benzodiazepine withdrawal. As norepinephrine has been shown to have anticonvulsant properties, bupropion's inhibitory effects on NET are thought to contribute to its pro-convulsant activity. Bupropion has been shown to increase blood pressure and pose a risk for exacerbation of unmanaged or pre-existing hypertension, however, clinical trials of bupropion in smokers with CVD have not identified an increased incidence of CV events including stroke or heart attack. In clinical trials, the mean increase in systolic blood pressure associated with the use of bupropion was found to be 1.3 mmHg. •Pharmacodynamics (Drug B): Nitrazepam is a type of benzodiazepine drug. It is a powerful hypnotic drug which possesses strong sedative, anxiolytic, amnestic, anticonvulsant, and skeletal muscle relaxant properties. Nitrazepam shortens the time required to fall asleep and lengthens the duration of sleep. It is also useful for the management of myoclonic seizures. •Mechanism of action (Drug A): Bupropion is a norepinephrine/dopamine-reuptake inhibitor (NDRI) that exerts its pharmacological effects by weakly inhibiting the enzymes involved in the uptake of the neurotransmitters norepinephrine and dopamine from the synaptic cleft, therefore prolonging their duration of action within the neuronal synapse and the downstream effects of these neurotransmitters. More specifically, bupropion binds to the norepinephrine transporter (NET) and the dopamine transporter (DAT). Bupropion was originally classified as an "atypical" antidepressant because it does not exert the same effects as the classical antidepressants such as Monoamine Oxidase Inhibitors (MAOIs), Tricyclic Antidepressants (TCAs), or Selective Serotonin Reuptake Inhibitors (SSRIs). While it has comparable effectiveness to typical first-line options for the treatment of depression such as SSRIs, bupropion is a unique option for the treatment of MDD as it lacks any clinically relevant serotonergic effects, typical of other mood medications, or any effects on histamine or adrenaline receptors. Lack of activity at these receptors results in a more tolerable side effect profile; bupropion is less likely to cause sexual side effects, sedation, or weight gain as compared to SSRIs or TCAs, for example. When used as an aid to smoking cessation, bupropion is thought to confer its anti-craving and anti-withdrawal effects by inhibiting dopamine reuptake, which is thought to be involved in the reward pathways associated with nicotine, and through the antagonism of the nicotinic acetylcholinergic receptor (AChR), thereby blunting the effects of nicotine. Furthermore, the stimulatory effects produced by bupropion in the central nervous system are similar to nicotine's effects, making low doses of bupropion a suitable option as a nicotine substitute. When used in combination with naltrexone in the marketed product ContraveⓇ for chronic weight management, the two components are thought to have effects on areas of the brain involved in the regulation of food intake. This includes the hypothalamus, which is involved in appetite regulation, and the mesolimbic dopamine circuit, which is involved in reward pathways. Studies have shown that the combined activity of bupropion and naltrexone increase the firing rate of hypothalamic pro-opiomelanocortin (POMC) neurons and blockade of opioid receptor-mediated POMC auto-inhibition, which are associated with a reduction in food intake and increased energy expenditure. This combination was also found to reduce food intake when injected directly into the ventral tegmental area of the mesolimbic circuit in mice, which is an area associated with the regulation of reward pathways. •Mechanism of action (Drug B): Nitrazepam belongs to a group of medicines called benzodiazepines. This drug affects central benzodiazepine receptors, which are associated with inhibitory GABA (gamma amino butyric acid)receptors, leading to enhanced GABA binding activity. GABA is a major neurotransmitter in the brain, which causes somnolence, relaxation of muscles, a decrease in anxiety and general central nervous system depression. Nitrazepam has anticonvulsant properties that may be attributed to its ability to bind to voltage-dependent sodium channels. Sustained repetitive firing seems to be limited by benzodiazepines effect of slowing recovery of sodium channels from inactivation. •Absorption (Drug A): Bupropion is currently available in 3 distinct, but bioequivalent formulations: immediate release (IR), sustained-release (SR), and extended-release (XL). Immediate Release Formulation In humans, following oral administration of bupropion hydrochloride tablets, peak plasma bupropion concentrations are usually achieved within 2 hours. IR formulations provide a short duration of action and are therefore generally dosed three times per day. Sustained Release Formulation In humans, following oral administration of bupropion hydrochloride sustained-release tablets (SR), peak plasma concentration (Cmax) of bupropion is usually achieved within 3 hours. SR formulations provide a 12-hour extended release of medication and are therefore generally dosed twice per day. Extended Release Formulation Following single oral administration of bupropion hydrochloride extended-release tablets (XL) to healthy volunteers, the median time to peak plasma concentrations for bupropion was approximately 5 hours. The presence of food did not affect the peak concentration or area under the curve of bupropion. XL formulations provide a 24-hour extended release of medication and are therefore generally dosed once per day/ In a trial comparing chronic dosing with bupropion hydrochloride extended-release tablets (SR) 150 mg twice daily to bupropion immediate-release formulation 100 mg 3 times daily, the steady state Cmax for bupropion after bupropion hydrochloride sustained-release tablets (SR) administration was approximately 85% of those achieved after bupropion immediate-release formulation administration. Exposure (AUC) to bupropion was equivalent for both formulations. Bioequivalence was also demonstrated for all three major active metabolites (i.e., hydroxybupropion, threohydrobupropion and erythrohydrobupropion) for both Cmax and AUC. Thus, at steady state, bupropion hydrochloride sustained-release tablets (SR) given twice daily, and the immediate-release formulation of bupropion given 3 times daily, are essentially bioequivalent for both bupropion and the 3 quantitatively important metabolites. Furthermore, in a study comparing 14-day dosing with bupropion hydrochloride extended-release tablets (XL), 300 mg once-daily to the immediate-release formulation of bupropion at 100 mg 3 times daily, equivalence was demonstrated for peak plasma concentration and area under the curve for bupropion and the three metabolites (hydroxybupropion, threohydrobupropion, and erythrohydrobupropion). Additionally, in a study comparing 14-day dosing with bupropion hydrochloride extended-release tablets (XL) 300 mg once daily to the sustained-release formulation of bupropion at 150 mg 2 times daily, equivalence was demonstrated for peak plasma concentration and area under the curve for bupropion and the three metabolites. Bupropion hydrochloride extended-release tablets (SR) can be taken with or without food. Bupropion Cmax and AUC were increased by 11% to 35% and 16% to 19%, respectively, when bupropion hydrochloride extended-release tablets (SR) was administered with food to healthy volunteers in three trials. The food effect is not considered clinically significant. Following a single-dose administration of bupropion hydrochloride extended-release tablets (SR) in humans, Cmax of bupropion's metabolite hydroxybupropion occurs approximately 6 hours post-dose and is approximately 10 times the peak level of the parent drug at steady state. The elimination half-life of hydroxybupropion is approximately 20 (±5) hours and its AUC at steady state is about 17 times that of bupropion. The times to peak concentrations for the erythrohydrobupropion and threohydrobupropion metabolites are similar to that of the hydroxybupropion metabolite. However, their elimination half-lives are longer, 33(±10) and 37 (±13) hours, respectively, and steady-state AUCs are 1.5 and 7 times that of bupropion, respectively. •Absorption (Drug B): Bioavailability is 53-94% following oral administration. •Volume of distribution (Drug A): No volume of distribution available •Volume of distribution (Drug B): No volume of distribution available •Protein binding (Drug A): In vitro tests show that bupropion is 84% bound to human plasma proteins at concentrations up to 200 mcg per mL. The extent of protein binding of the hydroxybupropion metabolite is similar to that for bupropion, whereas the extent of protein binding of the threohydrobupropion metabolite is about half that seen with bupropion. •Protein binding (Drug B): No protein binding available •Metabolism (Drug A): Bupropion is extensively metabolized in humans. Three metabolites are active: hydroxybupropion, which is formed via hydroxylation of the tert-butyl group of bupropion, and the amino-alcohol isomers, threohydrobupropion and erythrohydrobupropion, which are formed via reduction of the carbonyl group. In vitro findings suggest that CYP2B6 is the principal isoenzyme involved in the formation of hydroxybupropion, while cytochrome P450 enzymes are not involved in the formation of threohydrobupropion. Hydroxybupropion has been shown to have the same affinity as bupropion for the norepinephrine transporter (NET) but approximately 50% of its antidepressant activity despite reaching concentrations of ~10-fold higher than that of the parent drug. Oxidation of the bupropion side chain results in the formation of a glycine conjugate of meta-chlorobenzoic acid, which is then excreted as the major urinary metabolite. The potency and toxicity of the metabolites relative to bupropion have not been fully characterized. However, it has been demonstrated in an antidepressant screening test in mice that hydroxybupropion is one-half as potent as bupropion, while threohydrobupropion and erythrohydrobupropion are 5-fold less potent than bupropion. This may be of clinical importance because the plasma concentrations of the metabolites are as high as or higher than those of bupropion. Bupropion and its metabolites exhibit linear kinetics following chronic administration of 300 to 450 mg per day. •Metabolism (Drug B): No metabolism available •Route of elimination (Drug A): Bupropion is extensively metabolized in humans. Oxidation of the bupropion side chain results in the formation of a glycine conjugate of metachlorobenzoic acid, which is then excreted as the major urinary metabolite. Following oral administration of 200 mg of 14C-bupropion in humans, 87% and 10% of the radioactive dose were recovered in the urine and feces, respectively. However, the fraction of the oral dose of bupropion excreted unchanged was only 0.5%, a finding consistent with the extensive metabolism of bupropion. •Route of elimination (Drug B): No route of elimination available •Half-life (Drug A): 24 hours •Half-life (Drug B): 15-38 hours (mean elimination half life 26 hours). •Clearance (Drug A): No clearance available •Clearance (Drug B): No clearance available •Toxicity (Drug A): Symptoms of overdose include seizures, hallucinations, loss of consciousness, tachycardia, and cardiac arrest. •Toxicity (Drug B): An overdose of nitrazepam may lead to impaired breathing, dizziness, decreased cognition and balance, bluish nails and lips, slurred speech, and extreme somnolence, among others. In severe overdose, these symptoms may progress to a coma with a possibility of death. •Brand Names (Drug A): Aplenzin, Auvelity, Budeprion, Contrave, Forfivo, Wellbutrin, Zyban •Brand Names (Drug B): Mogadon •Synonyms (Drug A): No synonyms listed •Synonyms (Drug B): N-desmethylnimetazepam Nitrazepam Nitrazépam Nitrazepamum •Summary (Drug A): Bupropion is a norepinephrine and dopamine reuptake inhibitor used in the treatment of major depressive disorder (MDD), seasonal affective disorder (SAD), and as an aid to smoking cessation. •Summary (Drug B): Nitrazepam is a long-acting benzodiazepine with intermediate onset commonly used to treat panic disorders, severe anxiety, insomnia, and seizures. Output: Central nervous system (CNS) depressants can cause sedation, falls, respiratory depression, coma, and death.2,3 The potential interaction between a CNS depressant and another CNS depressant drug due to synergistic effects is well documented in the literature, although the risk and severity of CNS depression vary from each drug. The subject and affected drugs are both CNS depressants that, when co-administered, may result in a more profound CNS depression. As the risk and severity of CNS depression resulting from the combined use of CNS depressants vary from each agent, each interaction between CNS depressants should be considered individually. The severity of the interaction is moderate.

Does Bupropion and Nitric Oxide interact?

•Drug A: Bupropion •Drug B: Nitric Oxide •Severity: MINOR •Description: The serum concentration of Bupropion can be increased when it is combined with Nitric Oxide. •Extended Description: Bupropion is extensively metabolized to hydroxybupropion by CYP2B6. •Indication (Drug A): Bupropion is indicated for the treatment of major depressive disorder (MDD), seasonal affective disorder (SAD), and as an aid to smoking cessation. When used in combination with naltrexone as the marketed product ContraveⓇ, bupropion is indicated as an adjunct to a reduced-calorie diet and increased physical activity for chronic weight management in adults with an initial body mass index (BMI) of: 30 kg/m^2 or greater (obese) or 27 kg/m^2 or greater (overweight) in the presence of at least one weight-related comorbid condition (e.g., hypertension, type 2 diabetes mellitus, or dyslipidemia). Bupropion is also used off-label as a first-line treatment in patients with ADHD and comorbid bipolar disorder when used as an adjunct to mood stabilizers. •Indication (Drug B): For the treatment of term and near-term (>34 weeks) neonates with hypoxic respiratory failure •Pharmacodynamics (Drug A): Bupropion is chemically unrelated to tricyclic, tetracyclic, selective serotonin re-uptake inhibitors, or other known antidepressant agents. Compared to classical tricyclic antidepressants, Bupropion is a relatively weak inhibitor of the neuronal uptake of norepinephrine and dopamine. In addition, Bupropion does not inhibit monoamine oxidase. Bupropion has been found to be essentially inactive at the serotonin transporter (SERT)(IC50 >10 000 nM), however both bupropion and its primary metabolite hydroxybupropion have been found to block the function of cation-selective serotonin type 3A receptors (5-HT3ARs). Bupropion produces dose-related central nervous system (CNS) stimulant effects in animals, as evidenced by increased locomotor activity, increased rates of responding in various schedule-controlled operant behaviour tasks, and, at high doses, induction of mild stereotyped behaviour. Due to these stimulant effects and selective activity at dopamine and norepinephrine receptors, bupropion has been identified as having an abuse potential. Bupropion has a similar structure to the controlled substance Cathinone, and has been identified as having mild amphetamine-like activity, particularly when inhaled or injected. Bupropion is also known to lower the seizure threshold, making any pre-existing seizure conditions a contraindication to its use. This risk is exacerbated when bupropion is combined with other drugs or substances that lower the seizure threshold, such as cocaine, or in clinical situations that would increase the risk of a seizure such as abrupt alcohol or benzodiazepine withdrawal. As norepinephrine has been shown to have anticonvulsant properties, bupropion's inhibitory effects on NET are thought to contribute to its pro-convulsant activity. Bupropion has been shown to increase blood pressure and pose a risk for exacerbation of unmanaged or pre-existing hypertension, however, clinical trials of bupropion in smokers with CVD have not identified an increased incidence of CV events including stroke or heart attack. In clinical trials, the mean increase in systolic blood pressure associated with the use of bupropion was found to be 1.3 mmHg. •Pharmacodynamics (Drug B): Persistent pulmonary hypertension of the newborn (PPHN) occurs as a primary developmental defect or as a condition secondary to other diseases such as meconium aspiration syndrome (MAS), pneumonia, sepsis, hyaline membrane disease, congenital diaphragmatic hernia (CDH), and pulmonary hypoplasia. In these states, pulmonary vascular resistance (PVR) is high, which results in hypoxemia secondary to right-to-left shunting of blood through the patent ductus arteriosus and foramen ovale. In neonates with PPHN, Nitric oxide improves oxygenation (as indicated by significant increases in PaO2). Nitric oxide appears to increase the partial pressure of arterial oxygen (PaO2) by dilating pulmonary vessels in better entilated areas of the lung, redistributing pulmonary blood flow away from lung regions with low ventilation/perfusion (V/Q) ratios toward regions with normal ratios. •Mechanism of action (Drug A): Bupropion is a norepinephrine/dopamine-reuptake inhibitor (NDRI) that exerts its pharmacological effects by weakly inhibiting the enzymes involved in the uptake of the neurotransmitters norepinephrine and dopamine from the synaptic cleft, therefore prolonging their duration of action within the neuronal synapse and the downstream effects of these neurotransmitters. More specifically, bupropion binds to the norepinephrine transporter (NET) and the dopamine transporter (DAT). Bupropion was originally classified as an "atypical" antidepressant because it does not exert the same effects as the classical antidepressants such as Monoamine Oxidase Inhibitors (MAOIs), Tricyclic Antidepressants (TCAs), or Selective Serotonin Reuptake Inhibitors (SSRIs). While it has comparable effectiveness to typical first-line options for the treatment of depression such as SSRIs, bupropion is a unique option for the treatment of MDD as it lacks any clinically relevant serotonergic effects, typical of other mood medications, or any effects on histamine or adrenaline receptors. Lack of activity at these receptors results in a more tolerable side effect profile; bupropion is less likely to cause sexual side effects, sedation, or weight gain as compared to SSRIs or TCAs, for example. When used as an aid to smoking cessation, bupropion is thought to confer its anti-craving and anti-withdrawal effects by inhibiting dopamine reuptake, which is thought to be involved in the reward pathways associated with nicotine, and through the antagonism of the nicotinic acetylcholinergic receptor (AChR), thereby blunting the effects of nicotine. Furthermore, the stimulatory effects produced by bupropion in the central nervous system are similar to nicotine's effects, making low doses of bupropion a suitable option as a nicotine substitute. When used in combination with naltrexone in the marketed product ContraveⓇ for chronic weight management, the two components are thought to have effects on areas of the brain involved in the regulation of food intake. This includes the hypothalamus, which is involved in appetite regulation, and the mesolimbic dopamine circuit, which is involved in reward pathways. Studies have shown that the combined activity of bupropion and naltrexone increase the firing rate of hypothalamic pro-opiomelanocortin (POMC) neurons and blockade of opioid receptor-mediated POMC auto-inhibition, which are associated with a reduction in food intake and increased energy expenditure. This combination was also found to reduce food intake when injected directly into the ventral tegmental area of the mesolimbic circuit in mice, which is an area associated with the regulation of reward pathways. •Mechanism of action (Drug B): Nitric oxide is a compound produced by many cells of the body. It relaxes vascular smooth muscle by binding to the heme moiety of cytosolic guanylate cyclase, activating guanylate cyclase and increasing intracellular levels of cyclic guanosine 3',5'-monophosphate, which then leads to vasodilation. When inhaled, nitric oxide produces pulmonary vasodilation. •Absorption (Drug A): Bupropion is currently available in 3 distinct, but bioequivalent formulations: immediate release (IR), sustained-release (SR), and extended-release (XL). Immediate Release Formulation In humans, following oral administration of bupropion hydrochloride tablets, peak plasma bupropion concentrations are usually achieved within 2 hours. IR formulations provide a short duration of action and are therefore generally dosed three times per day. Sustained Release Formulation In humans, following oral administration of bupropion hydrochloride sustained-release tablets (SR), peak plasma concentration (Cmax) of bupropion is usually achieved within 3 hours. SR formulations provide a 12-hour extended release of medication and are therefore generally dosed twice per day. Extended Release Formulation Following single oral administration of bupropion hydrochloride extended-release tablets (XL) to healthy volunteers, the median time to peak plasma concentrations for bupropion was approximately 5 hours. The presence of food did not affect the peak concentration or area under the curve of bupropion. XL formulations provide a 24-hour extended release of medication and are therefore generally dosed once per day/ In a trial comparing chronic dosing with bupropion hydrochloride extended-release tablets (SR) 150 mg twice daily to bupropion immediate-release formulation 100 mg 3 times daily, the steady state Cmax for bupropion after bupropion hydrochloride sustained-release tablets (SR) administration was approximately 85% of those achieved after bupropion immediate-release formulation administration. Exposure (AUC) to bupropion was equivalent for both formulations. Bioequivalence was also demonstrated for all three major active metabolites (i.e., hydroxybupropion, threohydrobupropion and erythrohydrobupropion) for both Cmax and AUC. Thus, at steady state, bupropion hydrochloride sustained-release tablets (SR) given twice daily, and the immediate-release formulation of bupropion given 3 times daily, are essentially bioequivalent for both bupropion and the 3 quantitatively important metabolites. Furthermore, in a study comparing 14-day dosing with bupropion hydrochloride extended-release tablets (XL), 300 mg once-daily to the immediate-release formulation of bupropion at 100 mg 3 times daily, equivalence was demonstrated for peak plasma concentration and area under the curve for bupropion and the three metabolites (hydroxybupropion, threohydrobupropion, and erythrohydrobupropion). Additionally, in a study comparing 14-day dosing with bupropion hydrochloride extended-release tablets (XL) 300 mg once daily to the sustained-release formulation of bupropion at 150 mg 2 times daily, equivalence was demonstrated for peak plasma concentration and area under the curve for bupropion and the three metabolites. Bupropion hydrochloride extended-release tablets (SR) can be taken with or without food. Bupropion Cmax and AUC were increased by 11% to 35% and 16% to 19%, respectively, when bupropion hydrochloride extended-release tablets (SR) was administered with food to healthy volunteers in three trials. The food effect is not considered clinically significant. Following a single-dose administration of bupropion hydrochloride extended-release tablets (SR) in humans, Cmax of bupropion's metabolite hydroxybupropion occurs approximately 6 hours post-dose and is approximately 10 times the peak level of the parent drug at steady state. The elimination half-life of hydroxybupropion is approximately 20 (±5) hours and its AUC at steady state is about 17 times that of bupropion. The times to peak concentrations for the erythrohydrobupropion and threohydrobupropion metabolites are similar to that of the hydroxybupropion metabolite. However, their elimination half-lives are longer, 33(±10) and 37 (±13) hours, respectively, and steady-state AUCs are 1.5 and 7 times that of bupropion, respectively. •Absorption (Drug B): Nitric oxide is absorbed systemically after inhalation. •Volume of distribution (Drug A): No volume of distribution available •Volume of distribution (Drug B): No volume of distribution available •Protein binding (Drug A): In vitro tests show that bupropion is 84% bound to human plasma proteins at concentrations up to 200 mcg per mL. The extent of protein binding of the hydroxybupropion metabolite is similar to that for bupropion, whereas the extent of protein binding of the threohydrobupropion metabolite is about half that seen with bupropion. •Protein binding (Drug B): No protein binding available •Metabolism (Drug A): Bupropion is extensively metabolized in humans. Three metabolites are active: hydroxybupropion, which is formed via hydroxylation of the tert-butyl group of bupropion, and the amino-alcohol isomers, threohydrobupropion and erythrohydrobupropion, which are formed via reduction of the carbonyl group. In vitro findings suggest that CYP2B6 is the principal isoenzyme involved in the formation of hydroxybupropion, while cytochrome P450 enzymes are not involved in the formation of threohydrobupropion. Hydroxybupropion has been shown to have the same affinity as bupropion for the norepinephrine transporter (NET) but approximately 50% of its antidepressant activity despite reaching concentrations of ~10-fold higher than that of the parent drug. Oxidation of the bupropion side chain results in the formation of a glycine conjugate of meta-chlorobenzoic acid, which is then excreted as the major urinary metabolite. The potency and toxicity of the metabolites relative to bupropion have not been fully characterized. However, it has been demonstrated in an antidepressant screening test in mice that hydroxybupropion is one-half as potent as bupropion, while threohydrobupropion and erythrohydrobupropion are 5-fold less potent than bupropion. This may be of clinical importance because the plasma concentrations of the metabolites are as high as or higher than those of bupropion. Bupropion and its metabolites exhibit linear kinetics following chronic administration of 300 to 450 mg per day. •Metabolism (Drug B): via pulmonary capillary bed •Route of elimination (Drug A): Bupropion is extensively metabolized in humans. Oxidation of the bupropion side chain results in the formation of a glycine conjugate of metachlorobenzoic acid, which is then excreted as the major urinary metabolite. Following oral administration of 200 mg of 14C-bupropion in humans, 87% and 10% of the radioactive dose were recovered in the urine and feces, respectively. However, the fraction of the oral dose of bupropion excreted unchanged was only 0.5%, a finding consistent with the extensive metabolism of bupropion. •Route of elimination (Drug B): Nitrate has been identified as the predominant nitric oxide metabolite excreted in the urine, accounting for >70% of the nitric oxide dose inhaled. •Half-life (Drug A): 24 hours •Half-life (Drug B): 2–6 seconds •Clearance (Drug A): No clearance available •Clearance (Drug B): No clearance available •Toxicity (Drug A): Symptoms of overdose include seizures, hallucinations, loss of consciousness, tachycardia, and cardiac arrest. •Toxicity (Drug B): No toxicity available •Brand Names (Drug A): Aplenzin, Auvelity, Budeprion, Contrave, Forfivo, Wellbutrin, Zyban •Brand Names (Drug B): Inomax, Kinox, Noxivent •Synonyms (Drug A): No synonyms listed •Synonyms (Drug B): No synonyms listed •Summary (Drug A): Bupropion is a norepinephrine and dopamine reuptake inhibitor used in the treatment of major depressive disorder (MDD), seasonal affective disorder (SAD), and as an aid to smoking cessation. •Summary (Drug B): Nitric Oxide is a vasodilating agent used in the treatment of hypoxic respiratory failure in premature neonates.

Bupropion is extensively metabolized to hydroxybupropion by CYP2B6. The severity of the interaction is minor.

Question: Does Bupropion and Nitric Oxide interact? Information: •Drug A: Bupropion •Drug B: Nitric Oxide •Severity: MINOR •Description: The serum concentration of Bupropion can be increased when it is combined with Nitric Oxide. •Extended Description: Bupropion is extensively metabolized to hydroxybupropion by CYP2B6. •Indication (Drug A): Bupropion is indicated for the treatment of major depressive disorder (MDD), seasonal affective disorder (SAD), and as an aid to smoking cessation. When used in combination with naltrexone as the marketed product ContraveⓇ, bupropion is indicated as an adjunct to a reduced-calorie diet and increased physical activity for chronic weight management in adults with an initial body mass index (BMI) of: 30 kg/m^2 or greater (obese) or 27 kg/m^2 or greater (overweight) in the presence of at least one weight-related comorbid condition (e.g., hypertension, type 2 diabetes mellitus, or dyslipidemia). Bupropion is also used off-label as a first-line treatment in patients with ADHD and comorbid bipolar disorder when used as an adjunct to mood stabilizers. •Indication (Drug B): For the treatment of term and near-term (>34 weeks) neonates with hypoxic respiratory failure •Pharmacodynamics (Drug A): Bupropion is chemically unrelated to tricyclic, tetracyclic, selective serotonin re-uptake inhibitors, or other known antidepressant agents. Compared to classical tricyclic antidepressants, Bupropion is a relatively weak inhibitor of the neuronal uptake of norepinephrine and dopamine. In addition, Bupropion does not inhibit monoamine oxidase. Bupropion has been found to be essentially inactive at the serotonin transporter (SERT)(IC50 >10 000 nM), however both bupropion and its primary metabolite hydroxybupropion have been found to block the function of cation-selective serotonin type 3A receptors (5-HT3ARs). Bupropion produces dose-related central nervous system (CNS) stimulant effects in animals, as evidenced by increased locomotor activity, increased rates of responding in various schedule-controlled operant behaviour tasks, and, at high doses, induction of mild stereotyped behaviour. Due to these stimulant effects and selective activity at dopamine and norepinephrine receptors, bupropion has been identified as having an abuse potential. Bupropion has a similar structure to the controlled substance Cathinone, and has been identified as having mild amphetamine-like activity, particularly when inhaled or injected. Bupropion is also known to lower the seizure threshold, making any pre-existing seizure conditions a contraindication to its use. This risk is exacerbated when bupropion is combined with other drugs or substances that lower the seizure threshold, such as cocaine, or in clinical situations that would increase the risk of a seizure such as abrupt alcohol or benzodiazepine withdrawal. As norepinephrine has been shown to have anticonvulsant properties, bupropion's inhibitory effects on NET are thought to contribute to its pro-convulsant activity. Bupropion has been shown to increase blood pressure and pose a risk for exacerbation of unmanaged or pre-existing hypertension, however, clinical trials of bupropion in smokers with CVD have not identified an increased incidence of CV events including stroke or heart attack. In clinical trials, the mean increase in systolic blood pressure associated with the use of bupropion was found to be 1.3 mmHg. •Pharmacodynamics (Drug B): Persistent pulmonary hypertension of the newborn (PPHN) occurs as a primary developmental defect or as a condition secondary to other diseases such as meconium aspiration syndrome (MAS), pneumonia, sepsis, hyaline membrane disease, congenital diaphragmatic hernia (CDH), and pulmonary hypoplasia. In these states, pulmonary vascular resistance (PVR) is high, which results in hypoxemia secondary to right-to-left shunting of blood through the patent ductus arteriosus and foramen ovale. In neonates with PPHN, Nitric oxide improves oxygenation (as indicated by significant increases in PaO2). Nitric oxide appears to increase the partial pressure of arterial oxygen (PaO2) by dilating pulmonary vessels in better entilated areas of the lung, redistributing pulmonary blood flow away from lung regions with low ventilation/perfusion (V/Q) ratios toward regions with normal ratios. •Mechanism of action (Drug A): Bupropion is a norepinephrine/dopamine-reuptake inhibitor (NDRI) that exerts its pharmacological effects by weakly inhibiting the enzymes involved in the uptake of the neurotransmitters norepinephrine and dopamine from the synaptic cleft, therefore prolonging their duration of action within the neuronal synapse and the downstream effects of these neurotransmitters. More specifically, bupropion binds to the norepinephrine transporter (NET) and the dopamine transporter (DAT). Bupropion was originally classified as an "atypical" antidepressant because it does not exert the same effects as the classical antidepressants such as Monoamine Oxidase Inhibitors (MAOIs), Tricyclic Antidepressants (TCAs), or Selective Serotonin Reuptake Inhibitors (SSRIs). While it has comparable effectiveness to typical first-line options for the treatment of depression such as SSRIs, bupropion is a unique option for the treatment of MDD as it lacks any clinically relevant serotonergic effects, typical of other mood medications, or any effects on histamine or adrenaline receptors. Lack of activity at these receptors results in a more tolerable side effect profile; bupropion is less likely to cause sexual side effects, sedation, or weight gain as compared to SSRIs or TCAs, for example. When used as an aid to smoking cessation, bupropion is thought to confer its anti-craving and anti-withdrawal effects by inhibiting dopamine reuptake, which is thought to be involved in the reward pathways associated with nicotine, and through the antagonism of the nicotinic acetylcholinergic receptor (AChR), thereby blunting the effects of nicotine. Furthermore, the stimulatory effects produced by bupropion in the central nervous system are similar to nicotine's effects, making low doses of bupropion a suitable option as a nicotine substitute. When used in combination with naltrexone in the marketed product ContraveⓇ for chronic weight management, the two components are thought to have effects on areas of the brain involved in the regulation of food intake. This includes the hypothalamus, which is involved in appetite regulation, and the mesolimbic dopamine circuit, which is involved in reward pathways. Studies have shown that the combined activity of bupropion and naltrexone increase the firing rate of hypothalamic pro-opiomelanocortin (POMC) neurons and blockade of opioid receptor-mediated POMC auto-inhibition, which are associated with a reduction in food intake and increased energy expenditure. This combination was also found to reduce food intake when injected directly into the ventral tegmental area of the mesolimbic circuit in mice, which is an area associated with the regulation of reward pathways. •Mechanism of action (Drug B): Nitric oxide is a compound produced by many cells of the body. It relaxes vascular smooth muscle by binding to the heme moiety of cytosolic guanylate cyclase, activating guanylate cyclase and increasing intracellular levels of cyclic guanosine 3',5'-monophosphate, which then leads to vasodilation. When inhaled, nitric oxide produces pulmonary vasodilation. •Absorption (Drug A): Bupropion is currently available in 3 distinct, but bioequivalent formulations: immediate release (IR), sustained-release (SR), and extended-release (XL). Immediate Release Formulation In humans, following oral administration of bupropion hydrochloride tablets, peak plasma bupropion concentrations are usually achieved within 2 hours. IR formulations provide a short duration of action and are therefore generally dosed three times per day. Sustained Release Formulation In humans, following oral administration of bupropion hydrochloride sustained-release tablets (SR), peak plasma concentration (Cmax) of bupropion is usually achieved within 3 hours. SR formulations provide a 12-hour extended release of medication and are therefore generally dosed twice per day. Extended Release Formulation Following single oral administration of bupropion hydrochloride extended-release tablets (XL) to healthy volunteers, the median time to peak plasma concentrations for bupropion was approximately 5 hours. The presence of food did not affect the peak concentration or area under the curve of bupropion. XL formulations provide a 24-hour extended release of medication and are therefore generally dosed once per day/ In a trial comparing chronic dosing with bupropion hydrochloride extended-release tablets (SR) 150 mg twice daily to bupropion immediate-release formulation 100 mg 3 times daily, the steady state Cmax for bupropion after bupropion hydrochloride sustained-release tablets (SR) administration was approximately 85% of those achieved after bupropion immediate-release formulation administration. Exposure (AUC) to bupropion was equivalent for both formulations. Bioequivalence was also demonstrated for all three major active metabolites (i.e., hydroxybupropion, threohydrobupropion and erythrohydrobupropion) for both Cmax and AUC. Thus, at steady state, bupropion hydrochloride sustained-release tablets (SR) given twice daily, and the immediate-release formulation of bupropion given 3 times daily, are essentially bioequivalent for both bupropion and the 3 quantitatively important metabolites. Furthermore, in a study comparing 14-day dosing with bupropion hydrochloride extended-release tablets (XL), 300 mg once-daily to the immediate-release formulation of bupropion at 100 mg 3 times daily, equivalence was demonstrated for peak plasma concentration and area under the curve for bupropion and the three metabolites (hydroxybupropion, threohydrobupropion, and erythrohydrobupropion). Additionally, in a study comparing 14-day dosing with bupropion hydrochloride extended-release tablets (XL) 300 mg once daily to the sustained-release formulation of bupropion at 150 mg 2 times daily, equivalence was demonstrated for peak plasma concentration and area under the curve for bupropion and the three metabolites. Bupropion hydrochloride extended-release tablets (SR) can be taken with or without food. Bupropion Cmax and AUC were increased by 11% to 35% and 16% to 19%, respectively, when bupropion hydrochloride extended-release tablets (SR) was administered with food to healthy volunteers in three trials. The food effect is not considered clinically significant. Following a single-dose administration of bupropion hydrochloride extended-release tablets (SR) in humans, Cmax of bupropion's metabolite hydroxybupropion occurs approximately 6 hours post-dose and is approximately 10 times the peak level of the parent drug at steady state. The elimination half-life of hydroxybupropion is approximately 20 (±5) hours and its AUC at steady state is about 17 times that of bupropion. The times to peak concentrations for the erythrohydrobupropion and threohydrobupropion metabolites are similar to that of the hydroxybupropion metabolite. However, their elimination half-lives are longer, 33(±10) and 37 (±13) hours, respectively, and steady-state AUCs are 1.5 and 7 times that of bupropion, respectively. •Absorption (Drug B): Nitric oxide is absorbed systemically after inhalation. •Volume of distribution (Drug A): No volume of distribution available •Volume of distribution (Drug B): No volume of distribution available •Protein binding (Drug A): In vitro tests show that bupropion is 84% bound to human plasma proteins at concentrations up to 200 mcg per mL. The extent of protein binding of the hydroxybupropion metabolite is similar to that for bupropion, whereas the extent of protein binding of the threohydrobupropion metabolite is about half that seen with bupropion. •Protein binding (Drug B): No protein binding available •Metabolism (Drug A): Bupropion is extensively metabolized in humans. Three metabolites are active: hydroxybupropion, which is formed via hydroxylation of the tert-butyl group of bupropion, and the amino-alcohol isomers, threohydrobupropion and erythrohydrobupropion, which are formed via reduction of the carbonyl group. In vitro findings suggest that CYP2B6 is the principal isoenzyme involved in the formation of hydroxybupropion, while cytochrome P450 enzymes are not involved in the formation of threohydrobupropion. Hydroxybupropion has been shown to have the same affinity as bupropion for the norepinephrine transporter (NET) but approximately 50% of its antidepressant activity despite reaching concentrations of ~10-fold higher than that of the parent drug. Oxidation of the bupropion side chain results in the formation of a glycine conjugate of meta-chlorobenzoic acid, which is then excreted as the major urinary metabolite. The potency and toxicity of the metabolites relative to bupropion have not been fully characterized. However, it has been demonstrated in an antidepressant screening test in mice that hydroxybupropion is one-half as potent as bupropion, while threohydrobupropion and erythrohydrobupropion are 5-fold less potent than bupropion. This may be of clinical importance because the plasma concentrations of the metabolites are as high as or higher than those of bupropion. Bupropion and its metabolites exhibit linear kinetics following chronic administration of 300 to 450 mg per day. •Metabolism (Drug B): via pulmonary capillary bed •Route of elimination (Drug A): Bupropion is extensively metabolized in humans. Oxidation of the bupropion side chain results in the formation of a glycine conjugate of metachlorobenzoic acid, which is then excreted as the major urinary metabolite. Following oral administration of 200 mg of 14C-bupropion in humans, 87% and 10% of the radioactive dose were recovered in the urine and feces, respectively. However, the fraction of the oral dose of bupropion excreted unchanged was only 0.5%, a finding consistent with the extensive metabolism of bupropion. •Route of elimination (Drug B): Nitrate has been identified as the predominant nitric oxide metabolite excreted in the urine, accounting for >70% of the nitric oxide dose inhaled. •Half-life (Drug A): 24 hours •Half-life (Drug B): 2–6 seconds •Clearance (Drug A): No clearance available •Clearance (Drug B): No clearance available •Toxicity (Drug A): Symptoms of overdose include seizures, hallucinations, loss of consciousness, tachycardia, and cardiac arrest. •Toxicity (Drug B): No toxicity available •Brand Names (Drug A): Aplenzin, Auvelity, Budeprion, Contrave, Forfivo, Wellbutrin, Zyban •Brand Names (Drug B): Inomax, Kinox, Noxivent •Synonyms (Drug A): No synonyms listed •Synonyms (Drug B): No synonyms listed •Summary (Drug A): Bupropion is a norepinephrine and dopamine reuptake inhibitor used in the treatment of major depressive disorder (MDD), seasonal affective disorder (SAD), and as an aid to smoking cessation. •Summary (Drug B): Nitric Oxide is a vasodilating agent used in the treatment of hypoxic respiratory failure in premature neonates. Output: Bupropion is extensively metabolized to hydroxybupropion by CYP2B6. The severity of the interaction is minor.

Does Bupropion and Nitrofurantoin interact?

•Drug A: Bupropion •Drug B: Nitrofurantoin •Severity: MINOR •Description: Nitrofurantoin may decrease the excretion rate of Bupropion which could result in a higher serum level. •Extended Description: The renal excretion of drugs is the overall result of a combination of kidney processes that include glomerular filtration, passive diffusion, tubular secretion, and tubular reabsorption. Since two of these mechanisms - tubular secretion and reabsorption - are saturable processes , they are consequently susceptible to competition between multiple substrates excreted by the kidneys. If two or more medications that are mainly renally excreted are co-administered, they may compete for renal elimination; there is a large likelihood that one agent may "out-compete" or saturate the renal excretion mechanisms before the other concomitantly administered agent(s) are excreted. As a result, the elimination of these other concurrently administered agents may be inhibited or otherwise delayed, which could lead to increases in their serum concentrations and the risk, incidence, and/or severity of adverse effects associated with the exposure to such drugs. •Indication (Drug A): Bupropion is indicated for the treatment of major depressive disorder (MDD), seasonal affective disorder (SAD), and as an aid to smoking cessation. When used in combination with naltrexone as the marketed product ContraveⓇ, bupropion is indicated as an adjunct to a reduced-calorie diet and increased physical activity for chronic weight management in adults with an initial body mass index (BMI) of: 30 kg/m^2 or greater (obese) or 27 kg/m^2 or greater (overweight) in the presence of at least one weight-related comorbid condition (e.g., hypertension, type 2 diabetes mellitus, or dyslipidemia). Bupropion is also used off-label as a first-line treatment in patients with ADHD and comorbid bipolar disorder when used as an adjunct to mood stabilizers. •Indication (Drug B): Nitrofurantoin is indicated to treat acute uncomplicated urinary tract infections. •Pharmacodynamics (Drug A): Bupropion is chemically unrelated to tricyclic, tetracyclic, selective serotonin re-uptake inhibitors, or other known antidepressant agents. Compared to classical tricyclic antidepressants, Bupropion is a relatively weak inhibitor of the neuronal uptake of norepinephrine and dopamine. In addition, Bupropion does not inhibit monoamine oxidase. Bupropion has been found to be essentially inactive at the serotonin transporter (SERT)(IC50 >10 000 nM), however both bupropion and its primary metabolite hydroxybupropion have been found to block the function of cation-selective serotonin type 3A receptors (5-HT3ARs). Bupropion produces dose-related central nervous system (CNS) stimulant effects in animals, as evidenced by increased locomotor activity, increased rates of responding in various schedule-controlled operant behaviour tasks, and, at high doses, induction of mild stereotyped behaviour. Due to these stimulant effects and selective activity at dopamine and norepinephrine receptors, bupropion has been identified as having an abuse potential. Bupropion has a similar structure to the controlled substance Cathinone, and has been identified as having mild amphetamine-like activity, particularly when inhaled or injected. Bupropion is also known to lower the seizure threshold, making any pre-existing seizure conditions a contraindication to its use. This risk is exacerbated when bupropion is combined with other drugs or substances that lower the seizure threshold, such as cocaine, or in clinical situations that would increase the risk of a seizure such as abrupt alcohol or benzodiazepine withdrawal. As norepinephrine has been shown to have anticonvulsant properties, bupropion's inhibitory effects on NET are thought to contribute to its pro-convulsant activity. Bupropion has been shown to increase blood pressure and pose a risk for exacerbation of unmanaged or pre-existing hypertension, however, clinical trials of bupropion in smokers with CVD have not identified an increased incidence of CV events including stroke or heart attack. In clinical trials, the mean increase in systolic blood pressure associated with the use of bupropion was found to be 1.3 mmHg. •Pharmacodynamics (Drug B): Nitrofurantoin interferes with vital processes in bacteria, which leads to their death. Nitrofurantoin rapidly reaches therapeutic concentrations in the urine and is also cleared rapidly. •Mechanism of action (Drug A): Bupropion is a norepinephrine/dopamine-reuptake inhibitor (NDRI) that exerts its pharmacological effects by weakly inhibiting the enzymes involved in the uptake of the neurotransmitters norepinephrine and dopamine from the synaptic cleft, therefore prolonging their duration of action within the neuronal synapse and the downstream effects of these neurotransmitters. More specifically, bupropion binds to the norepinephrine transporter (NET) and the dopamine transporter (DAT). Bupropion was originally classified as an "atypical" antidepressant because it does not exert the same effects as the classical antidepressants such as Monoamine Oxidase Inhibitors (MAOIs), Tricyclic Antidepressants (TCAs), or Selective Serotonin Reuptake Inhibitors (SSRIs). While it has comparable effectiveness to typical first-line options for the treatment of depression such as SSRIs, bupropion is a unique option for the treatment of MDD as it lacks any clinically relevant serotonergic effects, typical of other mood medications, or any effects on histamine or adrenaline receptors. Lack of activity at these receptors results in a more tolerable side effect profile; bupropion is less likely to cause sexual side effects, sedation, or weight gain as compared to SSRIs or TCAs, for example. When used as an aid to smoking cessation, bupropion is thought to confer its anti-craving and anti-withdrawal effects by inhibiting dopamine reuptake, which is thought to be involved in the reward pathways associated with nicotine, and through the antagonism of the nicotinic acetylcholinergic receptor (AChR), thereby blunting the effects of nicotine. Furthermore, the stimulatory effects produced by bupropion in the central nervous system are similar to nicotine's effects, making low doses of bupropion a suitable option as a nicotine substitute. When used in combination with naltrexone in the marketed product ContraveⓇ for chronic weight management, the two components are thought to have effects on areas of the brain involved in the regulation of food intake. This includes the hypothalamus, which is involved in appetite regulation, and the mesolimbic dopamine circuit, which is involved in reward pathways. Studies have shown that the combined activity of bupropion and naltrexone increase the firing rate of hypothalamic pro-opiomelanocortin (POMC) neurons and blockade of opioid receptor-mediated POMC auto-inhibition, which are associated with a reduction in food intake and increased energy expenditure. This combination was also found to reduce food intake when injected directly into the ventral tegmental area of the mesolimbic circuit in mice, which is an area associated with the regulation of reward pathways. •Mechanism of action (Drug B): Nitrofurantoin is converted by bacterial nitroreductases to electrophilic intermediates which inhibit the citric acid cycle as well as synthesis of DNA, RNA, and protein. •Absorption (Drug A): Bupropion is currently available in 3 distinct, but bioequivalent formulations: immediate release (IR), sustained-release (SR), and extended-release (XL). Immediate Release Formulation In humans, following oral administration of bupropion hydrochloride tablets, peak plasma bupropion concentrations are usually achieved within 2 hours. IR formulations provide a short duration of action and are therefore generally dosed three times per day. Sustained Release Formulation In humans, following oral administration of bupropion hydrochloride sustained-release tablets (SR), peak plasma concentration (Cmax) of bupropion is usually achieved within 3 hours. SR formulations provide a 12-hour extended release of medication and are therefore generally dosed twice per day. Extended Release Formulation Following single oral administration of bupropion hydrochloride extended-release tablets (XL) to healthy volunteers, the median time to peak plasma concentrations for bupropion was approximately 5 hours. The presence of food did not affect the peak concentration or area under the curve of bupropion. XL formulations provide a 24-hour extended release of medication and are therefore generally dosed once per day/ In a trial comparing chronic dosing with bupropion hydrochloride extended-release tablets (SR) 150 mg twice daily to bupropion immediate-release formulation 100 mg 3 times daily, the steady state Cmax for bupropion after bupropion hydrochloride sustained-release tablets (SR) administration was approximately 85% of those achieved after bupropion immediate-release formulation administration. Exposure (AUC) to bupropion was equivalent for both formulations. Bioequivalence was also demonstrated for all three major active metabolites (i.e., hydroxybupropion, threohydrobupropion and erythrohydrobupropion) for both Cmax and AUC. Thus, at steady state, bupropion hydrochloride sustained-release tablets (SR) given twice daily, and the immediate-release formulation of bupropion given 3 times daily, are essentially bioequivalent for both bupropion and the 3 quantitatively important metabolites. Furthermore, in a study comparing 14-day dosing with bupropion hydrochloride extended-release tablets (XL), 300 mg once-daily to the immediate-release formulation of bupropion at 100 mg 3 times daily, equivalence was demonstrated for peak plasma concentration and area under the curve for bupropion and the three metabolites (hydroxybupropion, threohydrobupropion, and erythrohydrobupropion). Additionally, in a study comparing 14-day dosing with bupropion hydrochloride extended-release tablets (XL) 300 mg once daily to the sustained-release formulation of bupropion at 150 mg 2 times daily, equivalence was demonstrated for peak plasma concentration and area under the curve for bupropion and the three metabolites. Bupropion hydrochloride extended-release tablets (SR) can be taken with or without food. Bupropion Cmax and AUC were increased by 11% to 35% and 16% to 19%, respectively, when bupropion hydrochloride extended-release tablets (SR) was administered with food to healthy volunteers in three trials. The food effect is not considered clinically significant. Following a single-dose administration of bupropion hydrochloride extended-release tablets (SR) in humans, Cmax of bupropion's metabolite hydroxybupropion occurs approximately 6 hours post-dose and is approximately 10 times the peak level of the parent drug at steady state. The elimination half-life of hydroxybupropion is approximately 20 (±5) hours and its AUC at steady state is about 17 times that of bupropion. The times to peak concentrations for the erythrohydrobupropion and threohydrobupropion metabolites are similar to that of the hydroxybupropion metabolite. However, their elimination half-lives are longer, 33(±10) and 37 (±13) hours, respectively, and steady-state AUCs are 1.5 and 7 times that of bupropion, respectively. •Absorption (Drug B): Nitrofurantoin reaches a C max of 0.875-0.963mg/L with an AUC of 2.21-2.42mg*h/L. It is 38.8-44.3% bioavailable. Taking nitrofurantoin with food increases the absorption and duration of therapeutic concentrations in the urine. •Volume of distribution (Drug A): No volume of distribution available •Volume of distribution (Drug B): Data regarding the volume of distribution in humans is scarce but it has been reported as 0.46L/kg in dogs. •Protein binding (Drug A): In vitro tests show that bupropion is 84% bound to human plasma proteins at concentrations up to 200 mcg per mL. The extent of protein binding of the hydroxybupropion metabolite is similar to that for bupropion, whereas the extent of protein binding of the threohydrobupropion metabolite is about half that seen with bupropion. •Protein binding (Drug B): Nitrofurantoin could be up to 90% protein bound in plasma. •Metabolism (Drug A): Bupropion is extensively metabolized in humans. Three metabolites are active: hydroxybupropion, which is formed via hydroxylation of the tert-butyl group of bupropion, and the amino-alcohol isomers, threohydrobupropion and erythrohydrobupropion, which are formed via reduction of the carbonyl group. In vitro findings suggest that CYP2B6 is the principal isoenzyme involved in the formation of hydroxybupropion, while cytochrome P450 enzymes are not involved in the formation of threohydrobupropion. Hydroxybupropion has been shown to have the same affinity as bupropion for the norepinephrine transporter (NET) but approximately 50% of its antidepressant activity despite reaching concentrations of ~10-fold higher than that of the parent drug. Oxidation of the bupropion side chain results in the formation of a glycine conjugate of meta-chlorobenzoic acid, which is then excreted as the major urinary metabolite. The potency and toxicity of the metabolites relative to bupropion have not been fully characterized. However, it has been demonstrated in an antidepressant screening test in mice that hydroxybupropion is one-half as potent as bupropion, while threohydrobupropion and erythrohydrobupropion are 5-fold less potent than bupropion. This may be of clinical importance because the plasma concentrations of the metabolites are as high as or higher than those of bupropion. Bupropion and its metabolites exhibit linear kinetics following chronic administration of 300 to 450 mg per day. •Metabolism (Drug B): 0.8-1.8% of a dose is metabolized to aminofurantoin, and ≤0.9% of a dose is metabolized to other metabolites. •Route of elimination (Drug A): Bupropion is extensively metabolized in humans. Oxidation of the bupropion side chain results in the formation of a glycine conjugate of metachlorobenzoic acid, which is then excreted as the major urinary metabolite. Following oral administration of 200 mg of 14C-bupropion in humans, 87% and 10% of the radioactive dose were recovered in the urine and feces, respectively. However, the fraction of the oral dose of bupropion excreted unchanged was only 0.5%, a finding consistent with the extensive metabolism of bupropion. •Route of elimination (Drug B): 27-50% of an oral dose is excreted in the urine as unchanged nitrofurantoin. 90% of the total dose is eliminated in the urine. •Half-life (Drug A): 24 hours •Half-life (Drug B): The half life of nitrofurantoin is 0.72-0.78h. •Clearance (Drug A): No clearance available •Clearance (Drug B): The clearance of nitrofurantoin is 16.7-19.4L/h. •Toxicity (Drug A): Symptoms of overdose include seizures, hallucinations, loss of consciousness, tachycardia, and cardiac arrest. •Toxicity (Drug B): Symptoms of overdose include vomiting. In case of overdose, induce vomiting if it has not already occurred and increase fluid intake to promote urination. In extreme cases, nitrofurantoin can be removed from circulation by dialysis. •Brand Names (Drug A): Aplenzin, Auvelity, Budeprion, Contrave, Forfivo, Wellbutrin, Zyban •Brand Names (Drug B): Furadantin, Macrobid, Macrodantin •Synonyms (Drug A): No synonyms listed •Synonyms (Drug B): 5-Nitrofurantoin Nitrofurantoin Nitrofurantoin macrocrystal Nitrofurantoin macrocrystalline nitrofurantoina nitrofurantoine nitrofurantoinum •Summary (Drug A): Bupropion is a norepinephrine and dopamine reuptake inhibitor used in the treatment of major depressive disorder (MDD), seasonal affective disorder (SAD), and as an aid to smoking cessation. •Summary (Drug B): Nitrofurantoin is an antibiotic used to treat urinary tract infections.

The renal excretion of drugs is the overall result of a combination of kidney processes that include glomerular filtration, passive diffusion, tubular secretion, and tubular reabsorption. Since two of these mechanisms - tubular secretion and reabsorption - are saturable processes , they are consequently susceptible to competition between multiple substrates excreted by the kidneys. If two or more medications that are mainly renally excreted are co-administered, they may compete for renal elimination; there is a large likelihood that one agent may "out-compete" or saturate the renal excretion mechanisms before the other concomitantly administered agent(s) are excreted. As a result, the elimination of these other concurrently administered agents may be inhibited or otherwise delayed, which could lead to increases in their serum concentrations and the risk, incidence, and/or severity of adverse effects associated with the exposure to such drugs. The severity of the interaction is minor.

Question: Does Bupropion and Nitrofurantoin interact? Information: •Drug A: Bupropion •Drug B: Nitrofurantoin •Severity: MINOR •Description: Nitrofurantoin may decrease the excretion rate of Bupropion which could result in a higher serum level. •Extended Description: The renal excretion of drugs is the overall result of a combination of kidney processes that include glomerular filtration, passive diffusion, tubular secretion, and tubular reabsorption. Since two of these mechanisms - tubular secretion and reabsorption - are saturable processes , they are consequently susceptible to competition between multiple substrates excreted by the kidneys. If two or more medications that are mainly renally excreted are co-administered, they may compete for renal elimination; there is a large likelihood that one agent may "out-compete" or saturate the renal excretion mechanisms before the other concomitantly administered agent(s) are excreted. As a result, the elimination of these other concurrently administered agents may be inhibited or otherwise delayed, which could lead to increases in their serum concentrations and the risk, incidence, and/or severity of adverse effects associated with the exposure to such drugs. •Indication (Drug A): Bupropion is indicated for the treatment of major depressive disorder (MDD), seasonal affective disorder (SAD), and as an aid to smoking cessation. When used in combination with naltrexone as the marketed product ContraveⓇ, bupropion is indicated as an adjunct to a reduced-calorie diet and increased physical activity for chronic weight management in adults with an initial body mass index (BMI) of: 30 kg/m^2 or greater (obese) or 27 kg/m^2 or greater (overweight) in the presence of at least one weight-related comorbid condition (e.g., hypertension, type 2 diabetes mellitus, or dyslipidemia). Bupropion is also used off-label as a first-line treatment in patients with ADHD and comorbid bipolar disorder when used as an adjunct to mood stabilizers. •Indication (Drug B): Nitrofurantoin is indicated to treat acute uncomplicated urinary tract infections. •Pharmacodynamics (Drug A): Bupropion is chemically unrelated to tricyclic, tetracyclic, selective serotonin re-uptake inhibitors, or other known antidepressant agents. Compared to classical tricyclic antidepressants, Bupropion is a relatively weak inhibitor of the neuronal uptake of norepinephrine and dopamine. In addition, Bupropion does not inhibit monoamine oxidase. Bupropion has been found to be essentially inactive at the serotonin transporter (SERT)(IC50 >10 000 nM), however both bupropion and its primary metabolite hydroxybupropion have been found to block the function of cation-selective serotonin type 3A receptors (5-HT3ARs). Bupropion produces dose-related central nervous system (CNS) stimulant effects in animals, as evidenced by increased locomotor activity, increased rates of responding in various schedule-controlled operant behaviour tasks, and, at high doses, induction of mild stereotyped behaviour. Due to these stimulant effects and selective activity at dopamine and norepinephrine receptors, bupropion has been identified as having an abuse potential. Bupropion has a similar structure to the controlled substance Cathinone, and has been identified as having mild amphetamine-like activity, particularly when inhaled or injected. Bupropion is also known to lower the seizure threshold, making any pre-existing seizure conditions a contraindication to its use. This risk is exacerbated when bupropion is combined with other drugs or substances that lower the seizure threshold, such as cocaine, or in clinical situations that would increase the risk of a seizure such as abrupt alcohol or benzodiazepine withdrawal. As norepinephrine has been shown to have anticonvulsant properties, bupropion's inhibitory effects on NET are thought to contribute to its pro-convulsant activity. Bupropion has been shown to increase blood pressure and pose a risk for exacerbation of unmanaged or pre-existing hypertension, however, clinical trials of bupropion in smokers with CVD have not identified an increased incidence of CV events including stroke or heart attack. In clinical trials, the mean increase in systolic blood pressure associated with the use of bupropion was found to be 1.3 mmHg. •Pharmacodynamics (Drug B): Nitrofurantoin interferes with vital processes in bacteria, which leads to their death. Nitrofurantoin rapidly reaches therapeutic concentrations in the urine and is also cleared rapidly. •Mechanism of action (Drug A): Bupropion is a norepinephrine/dopamine-reuptake inhibitor (NDRI) that exerts its pharmacological effects by weakly inhibiting the enzymes involved in the uptake of the neurotransmitters norepinephrine and dopamine from the synaptic cleft, therefore prolonging their duration of action within the neuronal synapse and the downstream effects of these neurotransmitters. More specifically, bupropion binds to the norepinephrine transporter (NET) and the dopamine transporter (DAT). Bupropion was originally classified as an "atypical" antidepressant because it does not exert the same effects as the classical antidepressants such as Monoamine Oxidase Inhibitors (MAOIs), Tricyclic Antidepressants (TCAs), or Selective Serotonin Reuptake Inhibitors (SSRIs). While it has comparable effectiveness to typical first-line options for the treatment of depression such as SSRIs, bupropion is a unique option for the treatment of MDD as it lacks any clinically relevant serotonergic effects, typical of other mood medications, or any effects on histamine or adrenaline receptors. Lack of activity at these receptors results in a more tolerable side effect profile; bupropion is less likely to cause sexual side effects, sedation, or weight gain as compared to SSRIs or TCAs, for example. When used as an aid to smoking cessation, bupropion is thought to confer its anti-craving and anti-withdrawal effects by inhibiting dopamine reuptake, which is thought to be involved in the reward pathways associated with nicotine, and through the antagonism of the nicotinic acetylcholinergic receptor (AChR), thereby blunting the effects of nicotine. Furthermore, the stimulatory effects produced by bupropion in the central nervous system are similar to nicotine's effects, making low doses of bupropion a suitable option as a nicotine substitute. When used in combination with naltrexone in the marketed product ContraveⓇ for chronic weight management, the two components are thought to have effects on areas of the brain involved in the regulation of food intake. This includes the hypothalamus, which is involved in appetite regulation, and the mesolimbic dopamine circuit, which is involved in reward pathways. Studies have shown that the combined activity of bupropion and naltrexone increase the firing rate of hypothalamic pro-opiomelanocortin (POMC) neurons and blockade of opioid receptor-mediated POMC auto-inhibition, which are associated with a reduction in food intake and increased energy expenditure. This combination was also found to reduce food intake when injected directly into the ventral tegmental area of the mesolimbic circuit in mice, which is an area associated with the regulation of reward pathways. •Mechanism of action (Drug B): Nitrofurantoin is converted by bacterial nitroreductases to electrophilic intermediates which inhibit the citric acid cycle as well as synthesis of DNA, RNA, and protein. •Absorption (Drug A): Bupropion is currently available in 3 distinct, but bioequivalent formulations: immediate release (IR), sustained-release (SR), and extended-release (XL). Immediate Release Formulation In humans, following oral administration of bupropion hydrochloride tablets, peak plasma bupropion concentrations are usually achieved within 2 hours. IR formulations provide a short duration of action and are therefore generally dosed three times per day. Sustained Release Formulation In humans, following oral administration of bupropion hydrochloride sustained-release tablets (SR), peak plasma concentration (Cmax) of bupropion is usually achieved within 3 hours. SR formulations provide a 12-hour extended release of medication and are therefore generally dosed twice per day. Extended Release Formulation Following single oral administration of bupropion hydrochloride extended-release tablets (XL) to healthy volunteers, the median time to peak plasma concentrations for bupropion was approximately 5 hours. The presence of food did not affect the peak concentration or area under the curve of bupropion. XL formulations provide a 24-hour extended release of medication and are therefore generally dosed once per day/ In a trial comparing chronic dosing with bupropion hydrochloride extended-release tablets (SR) 150 mg twice daily to bupropion immediate-release formulation 100 mg 3 times daily, the steady state Cmax for bupropion after bupropion hydrochloride sustained-release tablets (SR) administration was approximately 85% of those achieved after bupropion immediate-release formulation administration. Exposure (AUC) to bupropion was equivalent for both formulations. Bioequivalence was also demonstrated for all three major active metabolites (i.e., hydroxybupropion, threohydrobupropion and erythrohydrobupropion) for both Cmax and AUC. Thus, at steady state, bupropion hydrochloride sustained-release tablets (SR) given twice daily, and the immediate-release formulation of bupropion given 3 times daily, are essentially bioequivalent for both bupropion and the 3 quantitatively important metabolites. Furthermore, in a study comparing 14-day dosing with bupropion hydrochloride extended-release tablets (XL), 300 mg once-daily to the immediate-release formulation of bupropion at 100 mg 3 times daily, equivalence was demonstrated for peak plasma concentration and area under the curve for bupropion and the three metabolites (hydroxybupropion, threohydrobupropion, and erythrohydrobupropion). Additionally, in a study comparing 14-day dosing with bupropion hydrochloride extended-release tablets (XL) 300 mg once daily to the sustained-release formulation of bupropion at 150 mg 2 times daily, equivalence was demonstrated for peak plasma concentration and area under the curve for bupropion and the three metabolites. Bupropion hydrochloride extended-release tablets (SR) can be taken with or without food. Bupropion Cmax and AUC were increased by 11% to 35% and 16% to 19%, respectively, when bupropion hydrochloride extended-release tablets (SR) was administered with food to healthy volunteers in three trials. The food effect is not considered clinically significant. Following a single-dose administration of bupropion hydrochloride extended-release tablets (SR) in humans, Cmax of bupropion's metabolite hydroxybupropion occurs approximately 6 hours post-dose and is approximately 10 times the peak level of the parent drug at steady state. The elimination half-life of hydroxybupropion is approximately 20 (±5) hours and its AUC at steady state is about 17 times that of bupropion. The times to peak concentrations for the erythrohydrobupropion and threohydrobupropion metabolites are similar to that of the hydroxybupropion metabolite. However, their elimination half-lives are longer, 33(±10) and 37 (±13) hours, respectively, and steady-state AUCs are 1.5 and 7 times that of bupropion, respectively. •Absorption (Drug B): Nitrofurantoin reaches a C max of 0.875-0.963mg/L with an AUC of 2.21-2.42mg*h/L. It is 38.8-44.3% bioavailable. Taking nitrofurantoin with food increases the absorption and duration of therapeutic concentrations in the urine. •Volume of distribution (Drug A): No volume of distribution available •Volume of distribution (Drug B): Data regarding the volume of distribution in humans is scarce but it has been reported as 0.46L/kg in dogs. •Protein binding (Drug A): In vitro tests show that bupropion is 84% bound to human plasma proteins at concentrations up to 200 mcg per mL. The extent of protein binding of the hydroxybupropion metabolite is similar to that for bupropion, whereas the extent of protein binding of the threohydrobupropion metabolite is about half that seen with bupropion. •Protein binding (Drug B): Nitrofurantoin could be up to 90% protein bound in plasma. •Metabolism (Drug A): Bupropion is extensively metabolized in humans. Three metabolites are active: hydroxybupropion, which is formed via hydroxylation of the tert-butyl group of bupropion, and the amino-alcohol isomers, threohydrobupropion and erythrohydrobupropion, which are formed via reduction of the carbonyl group. In vitro findings suggest that CYP2B6 is the principal isoenzyme involved in the formation of hydroxybupropion, while cytochrome P450 enzymes are not involved in the formation of threohydrobupropion. Hydroxybupropion has been shown to have the same affinity as bupropion for the norepinephrine transporter (NET) but approximately 50% of its antidepressant activity despite reaching concentrations of ~10-fold higher than that of the parent drug. Oxidation of the bupropion side chain results in the formation of a glycine conjugate of meta-chlorobenzoic acid, which is then excreted as the major urinary metabolite. The potency and toxicity of the metabolites relative to bupropion have not been fully characterized. However, it has been demonstrated in an antidepressant screening test in mice that hydroxybupropion is one-half as potent as bupropion, while threohydrobupropion and erythrohydrobupropion are 5-fold less potent than bupropion. This may be of clinical importance because the plasma concentrations of the metabolites are as high as or higher than those of bupropion. Bupropion and its metabolites exhibit linear kinetics following chronic administration of 300 to 450 mg per day. •Metabolism (Drug B): 0.8-1.8% of a dose is metabolized to aminofurantoin, and ≤0.9% of a dose is metabolized to other metabolites. •Route of elimination (Drug A): Bupropion is extensively metabolized in humans. Oxidation of the bupropion side chain results in the formation of a glycine conjugate of metachlorobenzoic acid, which is then excreted as the major urinary metabolite. Following oral administration of 200 mg of 14C-bupropion in humans, 87% and 10% of the radioactive dose were recovered in the urine and feces, respectively. However, the fraction of the oral dose of bupropion excreted unchanged was only 0.5%, a finding consistent with the extensive metabolism of bupropion. •Route of elimination (Drug B): 27-50% of an oral dose is excreted in the urine as unchanged nitrofurantoin. 90% of the total dose is eliminated in the urine. •Half-life (Drug A): 24 hours •Half-life (Drug B): The half life of nitrofurantoin is 0.72-0.78h. •Clearance (Drug A): No clearance available •Clearance (Drug B): The clearance of nitrofurantoin is 16.7-19.4L/h. •Toxicity (Drug A): Symptoms of overdose include seizures, hallucinations, loss of consciousness, tachycardia, and cardiac arrest. •Toxicity (Drug B): Symptoms of overdose include vomiting. In case of overdose, induce vomiting if it has not already occurred and increase fluid intake to promote urination. In extreme cases, nitrofurantoin can be removed from circulation by dialysis. •Brand Names (Drug A): Aplenzin, Auvelity, Budeprion, Contrave, Forfivo, Wellbutrin, Zyban •Brand Names (Drug B): Furadantin, Macrobid, Macrodantin •Synonyms (Drug A): No synonyms listed •Synonyms (Drug B): 5-Nitrofurantoin Nitrofurantoin Nitrofurantoin macrocrystal Nitrofurantoin macrocrystalline nitrofurantoina nitrofurantoine nitrofurantoinum •Summary (Drug A): Bupropion is a norepinephrine and dopamine reuptake inhibitor used in the treatment of major depressive disorder (MDD), seasonal affective disorder (SAD), and as an aid to smoking cessation. •Summary (Drug B): Nitrofurantoin is an antibiotic used to treat urinary tract infections. Output: The renal excretion of drugs is the overall result of a combination of kidney processes that include glomerular filtration, passive diffusion, tubular secretion, and tubular reabsorption. Since two of these mechanisms - tubular secretion and reabsorption - are saturable processes , they are consequently susceptible to competition between multiple substrates excreted by the kidneys. If two or more medications that are mainly renally excreted are co-administered, they may compete for renal elimination; there is a large likelihood that one agent may "out-compete" or saturate the renal excretion mechanisms before the other concomitantly administered agent(s) are excreted. As a result, the elimination of these other concurrently administered agents may be inhibited or otherwise delayed, which could lead to increases in their serum concentrations and the risk, incidence, and/or severity of adverse effects associated with the exposure to such drugs. The severity of the interaction is minor.

Does Bupropion and Nitroprusside interact?

•Drug A: Bupropion •Drug B: Nitroprusside •Severity: MINOR •Description: Nitroprusside may decrease the excretion rate of Bupropion which could result in a higher serum level. •Extended Description: The renal excretion of drugs is the overall result of a combination of kidney processes that include glomerular filtration, passive diffusion, tubular secretion, and tubular reabsorption. Since two of these mechanisms - tubular secretion and reabsorption - are saturable processes , they are consequently susceptible to competition between multiple substrates excreted by the kidneys. If two or more medications that are mainly renally excreted are co-administered, they may compete for renal elimination; there is a large likelihood that one agent may "out-compete" or saturate the renal excretion mechanisms before the other concomitantly administered agent(s) are excreted. As a result, the elimination of these other concurrently administered agents may be inhibited or otherwise delayed, which could lead to increases in their serum concentrations and the risk, incidence, and/or severity of adverse effects associated with the exposure to such drugs. •Indication (Drug A): Bupropion is indicated for the treatment of major depressive disorder (MDD), seasonal affective disorder (SAD), and as an aid to smoking cessation. When used in combination with naltrexone as the marketed product ContraveⓇ, bupropion is indicated as an adjunct to a reduced-calorie diet and increased physical activity for chronic weight management in adults with an initial body mass index (BMI) of: 30 kg/m^2 or greater (obese) or 27 kg/m^2 or greater (overweight) in the presence of at least one weight-related comorbid condition (e.g., hypertension, type 2 diabetes mellitus, or dyslipidemia). Bupropion is also used off-label as a first-line treatment in patients with ADHD and comorbid bipolar disorder when used as an adjunct to mood stabilizers. •Indication (Drug B): For immediate reduction of blood pressure of patients in hypertensive crises, reduce bleeding during surgery, and for the treatment of acute congestive heart failure •Pharmacodynamics (Drug A): Bupropion is chemically unrelated to tricyclic, tetracyclic, selective serotonin re-uptake inhibitors, or other known antidepressant agents. Compared to classical tricyclic antidepressants, Bupropion is a relatively weak inhibitor of the neuronal uptake of norepinephrine and dopamine. In addition, Bupropion does not inhibit monoamine oxidase. Bupropion has been found to be essentially inactive at the serotonin transporter (SERT)(IC50 >10 000 nM), however both bupropion and its primary metabolite hydroxybupropion have been found to block the function of cation-selective serotonin type 3A receptors (5-HT3ARs). Bupropion produces dose-related central nervous system (CNS) stimulant effects in animals, as evidenced by increased locomotor activity, increased rates of responding in various schedule-controlled operant behaviour tasks, and, at high doses, induction of mild stereotyped behaviour. Due to these stimulant effects and selective activity at dopamine and norepinephrine receptors, bupropion has been identified as having an abuse potential. Bupropion has a similar structure to the controlled substance Cathinone, and has been identified as having mild amphetamine-like activity, particularly when inhaled or injected. Bupropion is also known to lower the seizure threshold, making any pre-existing seizure conditions a contraindication to its use. This risk is exacerbated when bupropion is combined with other drugs or substances that lower the seizure threshold, such as cocaine, or in clinical situations that would increase the risk of a seizure such as abrupt alcohol or benzodiazepine withdrawal. As norepinephrine has been shown to have anticonvulsant properties, bupropion's inhibitory effects on NET are thought to contribute to its pro-convulsant activity. Bupropion has been shown to increase blood pressure and pose a risk for exacerbation of unmanaged or pre-existing hypertension, however, clinical trials of bupropion in smokers with CVD have not identified an increased incidence of CV events including stroke or heart attack. In clinical trials, the mean increase in systolic blood pressure associated with the use of bupropion was found to be 1.3 mmHg. •Pharmacodynamics (Drug B): Nitroprusside a powerful vasodilator relaxes the vascular smooth muscle and produce consequent dilatation of peripheral arteries and veins. Other smooth muscle (e.g., uterus, duodenum) is not affected. Sodium nitroprusside is more active on veins than on arteries. •Mechanism of action (Drug A): Bupropion is a norepinephrine/dopamine-reuptake inhibitor (NDRI) that exerts its pharmacological effects by weakly inhibiting the enzymes involved in the uptake of the neurotransmitters norepinephrine and dopamine from the synaptic cleft, therefore prolonging their duration of action within the neuronal synapse and the downstream effects of these neurotransmitters. More specifically, bupropion binds to the norepinephrine transporter (NET) and the dopamine transporter (DAT). Bupropion was originally classified as an "atypical" antidepressant because it does not exert the same effects as the classical antidepressants such as Monoamine Oxidase Inhibitors (MAOIs), Tricyclic Antidepressants (TCAs), or Selective Serotonin Reuptake Inhibitors (SSRIs). While it has comparable effectiveness to typical first-line options for the treatment of depression such as SSRIs, bupropion is a unique option for the treatment of MDD as it lacks any clinically relevant serotonergic effects, typical of other mood medications, or any effects on histamine or adrenaline receptors. Lack of activity at these receptors results in a more tolerable side effect profile; bupropion is less likely to cause sexual side effects, sedation, or weight gain as compared to SSRIs or TCAs, for example. When used as an aid to smoking cessation, bupropion is thought to confer its anti-craving and anti-withdrawal effects by inhibiting dopamine reuptake, which is thought to be involved in the reward pathways associated with nicotine, and through the antagonism of the nicotinic acetylcholinergic receptor (AChR), thereby blunting the effects of nicotine. Furthermore, the stimulatory effects produced by bupropion in the central nervous system are similar to nicotine's effects, making low doses of bupropion a suitable option as a nicotine substitute. When used in combination with naltrexone in the marketed product ContraveⓇ for chronic weight management, the two components are thought to have effects on areas of the brain involved in the regulation of food intake. This includes the hypothalamus, which is involved in appetite regulation, and the mesolimbic dopamine circuit, which is involved in reward pathways. Studies have shown that the combined activity of bupropion and naltrexone increase the firing rate of hypothalamic pro-opiomelanocortin (POMC) neurons and blockade of opioid receptor-mediated POMC auto-inhibition, which are associated with a reduction in food intake and increased energy expenditure. This combination was also found to reduce food intake when injected directly into the ventral tegmental area of the mesolimbic circuit in mice, which is an area associated with the regulation of reward pathways. •Mechanism of action (Drug B): One molecule of sodium nitroprusside is metabolized by combination with hemoglobin to produce one molecule of cyanmethemoglobin and four CN- ions; methemoglobin, obtained from hemoglobin, can sequester cyanide as cyanmethemoglobin; thiosulfate reacts with cyanide to produce thiocyanate; thiocyanate is eliminated in the urine; cyanide not otherwise removed binds to cytochromes. Cyanide ion is normally found in serum; it is derived from dietary substrates and from tobacco smoke. Cyanide binds avidly (but reversibly) to ferric ion (Fe+++), most body stores of which are found in erythrocyte methemoglobin (metHgb) and in mitochondrial cytochromes. When CN is infused or generated within the bloodstream, essentially all of it is bound to methemoglobin until intraerythrocytic methemoglobin has been saturated. Sodium nitroprusside is further broken down in the circulation to release nitric oxide (NO), which activates guanylate cyclase in the vascular smooth muscle. This leads to increased production of intracellular cGMP, which stimulates calcium ion movement from the cytoplasm to the endoplasmic reticulum, reducing the level of available calcium ions that can bind to calmodulin. This ultimately results in vascular smooth muscle relaxation and vessel dilation. •Absorption (Drug A): Bupropion is currently available in 3 distinct, but bioequivalent formulations: immediate release (IR), sustained-release (SR), and extended-release (XL). Immediate Release Formulation In humans, following oral administration of bupropion hydrochloride tablets, peak plasma bupropion concentrations are usually achieved within 2 hours. IR formulations provide a short duration of action and are therefore generally dosed three times per day. Sustained Release Formulation In humans, following oral administration of bupropion hydrochloride sustained-release tablets (SR), peak plasma concentration (Cmax) of bupropion is usually achieved within 3 hours. SR formulations provide a 12-hour extended release of medication and are therefore generally dosed twice per day. Extended Release Formulation Following single oral administration of bupropion hydrochloride extended-release tablets (XL) to healthy volunteers, the median time to peak plasma concentrations for bupropion was approximately 5 hours. The presence of food did not affect the peak concentration or area under the curve of bupropion. XL formulations provide a 24-hour extended release of medication and are therefore generally dosed once per day/ In a trial comparing chronic dosing with bupropion hydrochloride extended-release tablets (SR) 150 mg twice daily to bupropion immediate-release formulation 100 mg 3 times daily, the steady state Cmax for bupropion after bupropion hydrochloride sustained-release tablets (SR) administration was approximately 85% of those achieved after bupropion immediate-release formulation administration. Exposure (AUC) to bupropion was equivalent for both formulations. Bioequivalence was also demonstrated for all three major active metabolites (i.e., hydroxybupropion, threohydrobupropion and erythrohydrobupropion) for both Cmax and AUC. Thus, at steady state, bupropion hydrochloride sustained-release tablets (SR) given twice daily, and the immediate-release formulation of bupropion given 3 times daily, are essentially bioequivalent for both bupropion and the 3 quantitatively important metabolites. Furthermore, in a study comparing 14-day dosing with bupropion hydrochloride extended-release tablets (XL), 300 mg once-daily to the immediate-release formulation of bupropion at 100 mg 3 times daily, equivalence was demonstrated for peak plasma concentration and area under the curve for bupropion and the three metabolites (hydroxybupropion, threohydrobupropion, and erythrohydrobupropion). Additionally, in a study comparing 14-day dosing with bupropion hydrochloride extended-release tablets (XL) 300 mg once daily to the sustained-release formulation of bupropion at 150 mg 2 times daily, equivalence was demonstrated for peak plasma concentration and area under the curve for bupropion and the three metabolites. Bupropion hydrochloride extended-release tablets (SR) can be taken with or without food. Bupropion Cmax and AUC were increased by 11% to 35% and 16% to 19%, respectively, when bupropion hydrochloride extended-release tablets (SR) was administered with food to healthy volunteers in three trials. The food effect is not considered clinically significant. Following a single-dose administration of bupropion hydrochloride extended-release tablets (SR) in humans, Cmax of bupropion's metabolite hydroxybupropion occurs approximately 6 hours post-dose and is approximately 10 times the peak level of the parent drug at steady state. The elimination half-life of hydroxybupropion is approximately 20 (±5) hours and its AUC at steady state is about 17 times that of bupropion. The times to peak concentrations for the erythrohydrobupropion and threohydrobupropion metabolites are similar to that of the hydroxybupropion metabolite. However, their elimination half-lives are longer, 33(±10) and 37 (±13) hours, respectively, and steady-state AUCs are 1.5 and 7 times that of bupropion, respectively. •Absorption (Drug B): No absorption available •Volume of distribution (Drug A): No volume of distribution available •Volume of distribution (Drug B): No volume of distribution available •Protein binding (Drug A): In vitro tests show that bupropion is 84% bound to human plasma proteins at concentrations up to 200 mcg per mL. The extent of protein binding of the hydroxybupropion metabolite is similar to that for bupropion, whereas the extent of protein binding of the threohydrobupropion metabolite is about half that seen with bupropion. •Protein binding (Drug B): No protein binding available •Metabolism (Drug A): Bupropion is extensively metabolized in humans. Three metabolites are active: hydroxybupropion, which is formed via hydroxylation of the tert-butyl group of bupropion, and the amino-alcohol isomers, threohydrobupropion and erythrohydrobupropion, which are formed via reduction of the carbonyl group. In vitro findings suggest that CYP2B6 is the principal isoenzyme involved in the formation of hydroxybupropion, while cytochrome P450 enzymes are not involved in the formation of threohydrobupropion. Hydroxybupropion has been shown to have the same affinity as bupropion for the norepinephrine transporter (NET) but approximately 50% of its antidepressant activity despite reaching concentrations of ~10-fold higher than that of the parent drug. Oxidation of the bupropion side chain results in the formation of a glycine conjugate of meta-chlorobenzoic acid, which is then excreted as the major urinary metabolite. The potency and toxicity of the metabolites relative to bupropion have not been fully characterized. However, it has been demonstrated in an antidepressant screening test in mice that hydroxybupropion is one-half as potent as bupropion, while threohydrobupropion and erythrohydrobupropion are 5-fold less potent than bupropion. This may be of clinical importance because the plasma concentrations of the metabolites are as high as or higher than those of bupropion. Bupropion and its metabolites exhibit linear kinetics following chronic administration of 300 to 450 mg per day. •Metabolism (Drug B): Metabolized by reaction with hemoglobin to produce cyanmethemoglobin and cynide ions •Route of elimination (Drug A): Bupropion is extensively metabolized in humans. Oxidation of the bupropion side chain results in the formation of a glycine conjugate of metachlorobenzoic acid, which is then excreted as the major urinary metabolite. Following oral administration of 200 mg of 14C-bupropion in humans, 87% and 10% of the radioactive dose were recovered in the urine and feces, respectively. However, the fraction of the oral dose of bupropion excreted unchanged was only 0.5%, a finding consistent with the extensive metabolism of bupropion. •Route of elimination (Drug B): One molecule of sodium nitroprusside is metabolized by combination with hemoglobin to produce one molecule of cyanmethemoglobin and four CN¯ ions, thiosulfate reacts with cyanide to produce thiocyanate, thiocyanate is eliminated in the urine. •Half-life (Drug A): 24 hours •Half-life (Drug B): Approximately 2 minutes •Clearance (Drug A): No clearance available •Clearance (Drug B): No clearance available •Toxicity (Drug A): Symptoms of overdose include seizures, hallucinations, loss of consciousness, tachycardia, and cardiac arrest. •Toxicity (Drug B): Overdosage of nitroprusside can be manifested as excessive hypotension or cyanide toxicity or as thiocyanate toxicity. The acute intravenous mean lethal doses (LD 50 ) of nitroprusside in rabbits, dogs, mice, and rats are 2.8, 5.0, 8.4, and 11.2 mg/kg, respectively. •Brand Names (Drug A): Aplenzin, Auvelity, Budeprion, Contrave, Forfivo, Wellbutrin, Zyban •Brand Names (Drug B): Nipride, Nipride RTU, Nitropress •Synonyms (Drug A): No synonyms listed •Synonyms (Drug B): No synonyms listed •Summary (Drug A): Bupropion is a norepinephrine and dopamine reuptake inhibitor used in the treatment of major depressive disorder (MDD), seasonal affective disorder (SAD), and as an aid to smoking cessation. •Summary (Drug B): Nitroprusside is a direct acting vasodilator used to treat hypertension, to induce controlled hypotension to reduce postoperative bleeding, and to manage acute heart failure.

The renal excretion of drugs is the overall result of a combination of kidney processes that include glomerular filtration, passive diffusion, tubular secretion, and tubular reabsorption. Since two of these mechanisms - tubular secretion and reabsorption - are saturable processes , they are consequently susceptible to competition between multiple substrates excreted by the kidneys. If two or more medications that are mainly renally excreted are co-administered, they may compete for renal elimination; there is a large likelihood that one agent may "out-compete" or saturate the renal excretion mechanisms before the other concomitantly administered agent(s) are excreted. As a result, the elimination of these other concurrently administered agents may be inhibited or otherwise delayed, which could lead to increases in their serum concentrations and the risk, incidence, and/or severity of adverse effects associated with the exposure to such drugs. The severity of the interaction is minor.

Question: Does Bupropion and Nitroprusside interact? Information: •Drug A: Bupropion •Drug B: Nitroprusside •Severity: MINOR •Description: Nitroprusside may decrease the excretion rate of Bupropion which could result in a higher serum level. •Extended Description: The renal excretion of drugs is the overall result of a combination of kidney processes that include glomerular filtration, passive diffusion, tubular secretion, and tubular reabsorption. Since two of these mechanisms - tubular secretion and reabsorption - are saturable processes , they are consequently susceptible to competition between multiple substrates excreted by the kidneys. If two or more medications that are mainly renally excreted are co-administered, they may compete for renal elimination; there is a large likelihood that one agent may "out-compete" or saturate the renal excretion mechanisms before the other concomitantly administered agent(s) are excreted. As a result, the elimination of these other concurrently administered agents may be inhibited or otherwise delayed, which could lead to increases in their serum concentrations and the risk, incidence, and/or severity of adverse effects associated with the exposure to such drugs. •Indication (Drug A): Bupropion is indicated for the treatment of major depressive disorder (MDD), seasonal affective disorder (SAD), and as an aid to smoking cessation. When used in combination with naltrexone as the marketed product ContraveⓇ, bupropion is indicated as an adjunct to a reduced-calorie diet and increased physical activity for chronic weight management in adults with an initial body mass index (BMI) of: 30 kg/m^2 or greater (obese) or 27 kg/m^2 or greater (overweight) in the presence of at least one weight-related comorbid condition (e.g., hypertension, type 2 diabetes mellitus, or dyslipidemia). Bupropion is also used off-label as a first-line treatment in patients with ADHD and comorbid bipolar disorder when used as an adjunct to mood stabilizers. •Indication (Drug B): For immediate reduction of blood pressure of patients in hypertensive crises, reduce bleeding during surgery, and for the treatment of acute congestive heart failure •Pharmacodynamics (Drug A): Bupropion is chemically unrelated to tricyclic, tetracyclic, selective serotonin re-uptake inhibitors, or other known antidepressant agents. Compared to classical tricyclic antidepressants, Bupropion is a relatively weak inhibitor of the neuronal uptake of norepinephrine and dopamine. In addition, Bupropion does not inhibit monoamine oxidase. Bupropion has been found to be essentially inactive at the serotonin transporter (SERT)(IC50 >10 000 nM), however both bupropion and its primary metabolite hydroxybupropion have been found to block the function of cation-selective serotonin type 3A receptors (5-HT3ARs). Bupropion produces dose-related central nervous system (CNS) stimulant effects in animals, as evidenced by increased locomotor activity, increased rates of responding in various schedule-controlled operant behaviour tasks, and, at high doses, induction of mild stereotyped behaviour. Due to these stimulant effects and selective activity at dopamine and norepinephrine receptors, bupropion has been identified as having an abuse potential. Bupropion has a similar structure to the controlled substance Cathinone, and has been identified as having mild amphetamine-like activity, particularly when inhaled or injected. Bupropion is also known to lower the seizure threshold, making any pre-existing seizure conditions a contraindication to its use. This risk is exacerbated when bupropion is combined with other drugs or substances that lower the seizure threshold, such as cocaine, or in clinical situations that would increase the risk of a seizure such as abrupt alcohol or benzodiazepine withdrawal. As norepinephrine has been shown to have anticonvulsant properties, bupropion's inhibitory effects on NET are thought to contribute to its pro-convulsant activity. Bupropion has been shown to increase blood pressure and pose a risk for exacerbation of unmanaged or pre-existing hypertension, however, clinical trials of bupropion in smokers with CVD have not identified an increased incidence of CV events including stroke or heart attack. In clinical trials, the mean increase in systolic blood pressure associated with the use of bupropion was found to be 1.3 mmHg. •Pharmacodynamics (Drug B): Nitroprusside a powerful vasodilator relaxes the vascular smooth muscle and produce consequent dilatation of peripheral arteries and veins. Other smooth muscle (e.g., uterus, duodenum) is not affected. Sodium nitroprusside is more active on veins than on arteries. •Mechanism of action (Drug A): Bupropion is a norepinephrine/dopamine-reuptake inhibitor (NDRI) that exerts its pharmacological effects by weakly inhibiting the enzymes involved in the uptake of the neurotransmitters norepinephrine and dopamine from the synaptic cleft, therefore prolonging their duration of action within the neuronal synapse and the downstream effects of these neurotransmitters. More specifically, bupropion binds to the norepinephrine transporter (NET) and the dopamine transporter (DAT). Bupropion was originally classified as an "atypical" antidepressant because it does not exert the same effects as the classical antidepressants such as Monoamine Oxidase Inhibitors (MAOIs), Tricyclic Antidepressants (TCAs), or Selective Serotonin Reuptake Inhibitors (SSRIs). While it has comparable effectiveness to typical first-line options for the treatment of depression such as SSRIs, bupropion is a unique option for the treatment of MDD as it lacks any clinically relevant serotonergic effects, typical of other mood medications, or any effects on histamine or adrenaline receptors. Lack of activity at these receptors results in a more tolerable side effect profile; bupropion is less likely to cause sexual side effects, sedation, or weight gain as compared to SSRIs or TCAs, for example. When used as an aid to smoking cessation, bupropion is thought to confer its anti-craving and anti-withdrawal effects by inhibiting dopamine reuptake, which is thought to be involved in the reward pathways associated with nicotine, and through the antagonism of the nicotinic acetylcholinergic receptor (AChR), thereby blunting the effects of nicotine. Furthermore, the stimulatory effects produced by bupropion in the central nervous system are similar to nicotine's effects, making low doses of bupropion a suitable option as a nicotine substitute. When used in combination with naltrexone in the marketed product ContraveⓇ for chronic weight management, the two components are thought to have effects on areas of the brain involved in the regulation of food intake. This includes the hypothalamus, which is involved in appetite regulation, and the mesolimbic dopamine circuit, which is involved in reward pathways. Studies have shown that the combined activity of bupropion and naltrexone increase the firing rate of hypothalamic pro-opiomelanocortin (POMC) neurons and blockade of opioid receptor-mediated POMC auto-inhibition, which are associated with a reduction in food intake and increased energy expenditure. This combination was also found to reduce food intake when injected directly into the ventral tegmental area of the mesolimbic circuit in mice, which is an area associated with the regulation of reward pathways. •Mechanism of action (Drug B): One molecule of sodium nitroprusside is metabolized by combination with hemoglobin to produce one molecule of cyanmethemoglobin and four CN- ions; methemoglobin, obtained from hemoglobin, can sequester cyanide as cyanmethemoglobin; thiosulfate reacts with cyanide to produce thiocyanate; thiocyanate is eliminated in the urine; cyanide not otherwise removed binds to cytochromes. Cyanide ion is normally found in serum; it is derived from dietary substrates and from tobacco smoke. Cyanide binds avidly (but reversibly) to ferric ion (Fe+++), most body stores of which are found in erythrocyte methemoglobin (metHgb) and in mitochondrial cytochromes. When CN is infused or generated within the bloodstream, essentially all of it is bound to methemoglobin until intraerythrocytic methemoglobin has been saturated. Sodium nitroprusside is further broken down in the circulation to release nitric oxide (NO), which activates guanylate cyclase in the vascular smooth muscle. This leads to increased production of intracellular cGMP, which stimulates calcium ion movement from the cytoplasm to the endoplasmic reticulum, reducing the level of available calcium ions that can bind to calmodulin. This ultimately results in vascular smooth muscle relaxation and vessel dilation. •Absorption (Drug A): Bupropion is currently available in 3 distinct, but bioequivalent formulations: immediate release (IR), sustained-release (SR), and extended-release (XL). Immediate Release Formulation In humans, following oral administration of bupropion hydrochloride tablets, peak plasma bupropion concentrations are usually achieved within 2 hours. IR formulations provide a short duration of action and are therefore generally dosed three times per day. Sustained Release Formulation In humans, following oral administration of bupropion hydrochloride sustained-release tablets (SR), peak plasma concentration (Cmax) of bupropion is usually achieved within 3 hours. SR formulations provide a 12-hour extended release of medication and are therefore generally dosed twice per day. Extended Release Formulation Following single oral administration of bupropion hydrochloride extended-release tablets (XL) to healthy volunteers, the median time to peak plasma concentrations for bupropion was approximately 5 hours. The presence of food did not affect the peak concentration or area under the curve of bupropion. XL formulations provide a 24-hour extended release of medication and are therefore generally dosed once per day/ In a trial comparing chronic dosing with bupropion hydrochloride extended-release tablets (SR) 150 mg twice daily to bupropion immediate-release formulation 100 mg 3 times daily, the steady state Cmax for bupropion after bupropion hydrochloride sustained-release tablets (SR) administration was approximately 85% of those achieved after bupropion immediate-release formulation administration. Exposure (AUC) to bupropion was equivalent for both formulations. Bioequivalence was also demonstrated for all three major active metabolites (i.e., hydroxybupropion, threohydrobupropion and erythrohydrobupropion) for both Cmax and AUC. Thus, at steady state, bupropion hydrochloride sustained-release tablets (SR) given twice daily, and the immediate-release formulation of bupropion given 3 times daily, are essentially bioequivalent for both bupropion and the 3 quantitatively important metabolites. Furthermore, in a study comparing 14-day dosing with bupropion hydrochloride extended-release tablets (XL), 300 mg once-daily to the immediate-release formulation of bupropion at 100 mg 3 times daily, equivalence was demonstrated for peak plasma concentration and area under the curve for bupropion and the three metabolites (hydroxybupropion, threohydrobupropion, and erythrohydrobupropion). Additionally, in a study comparing 14-day dosing with bupropion hydrochloride extended-release tablets (XL) 300 mg once daily to the sustained-release formulation of bupropion at 150 mg 2 times daily, equivalence was demonstrated for peak plasma concentration and area under the curve for bupropion and the three metabolites. Bupropion hydrochloride extended-release tablets (SR) can be taken with or without food. Bupropion Cmax and AUC were increased by 11% to 35% and 16% to 19%, respectively, when bupropion hydrochloride extended-release tablets (SR) was administered with food to healthy volunteers in three trials. The food effect is not considered clinically significant. Following a single-dose administration of bupropion hydrochloride extended-release tablets (SR) in humans, Cmax of bupropion's metabolite hydroxybupropion occurs approximately 6 hours post-dose and is approximately 10 times the peak level of the parent drug at steady state. The elimination half-life of hydroxybupropion is approximately 20 (±5) hours and its AUC at steady state is about 17 times that of bupropion. The times to peak concentrations for the erythrohydrobupropion and threohydrobupropion metabolites are similar to that of the hydroxybupropion metabolite. However, their elimination half-lives are longer, 33(±10) and 37 (±13) hours, respectively, and steady-state AUCs are 1.5 and 7 times that of bupropion, respectively. •Absorption (Drug B): No absorption available •Volume of distribution (Drug A): No volume of distribution available •Volume of distribution (Drug B): No volume of distribution available •Protein binding (Drug A): In vitro tests show that bupropion is 84% bound to human plasma proteins at concentrations up to 200 mcg per mL. The extent of protein binding of the hydroxybupropion metabolite is similar to that for bupropion, whereas the extent of protein binding of the threohydrobupropion metabolite is about half that seen with bupropion. •Protein binding (Drug B): No protein binding available •Metabolism (Drug A): Bupropion is extensively metabolized in humans. Three metabolites are active: hydroxybupropion, which is formed via hydroxylation of the tert-butyl group of bupropion, and the amino-alcohol isomers, threohydrobupropion and erythrohydrobupropion, which are formed via reduction of the carbonyl group. In vitro findings suggest that CYP2B6 is the principal isoenzyme involved in the formation of hydroxybupropion, while cytochrome P450 enzymes are not involved in the formation of threohydrobupropion. Hydroxybupropion has been shown to have the same affinity as bupropion for the norepinephrine transporter (NET) but approximately 50% of its antidepressant activity despite reaching concentrations of ~10-fold higher than that of the parent drug. Oxidation of the bupropion side chain results in the formation of a glycine conjugate of meta-chlorobenzoic acid, which is then excreted as the major urinary metabolite. The potency and toxicity of the metabolites relative to bupropion have not been fully characterized. However, it has been demonstrated in an antidepressant screening test in mice that hydroxybupropion is one-half as potent as bupropion, while threohydrobupropion and erythrohydrobupropion are 5-fold less potent than bupropion. This may be of clinical importance because the plasma concentrations of the metabolites are as high as or higher than those of bupropion. Bupropion and its metabolites exhibit linear kinetics following chronic administration of 300 to 450 mg per day. •Metabolism (Drug B): Metabolized by reaction with hemoglobin to produce cyanmethemoglobin and cynide ions •Route of elimination (Drug A): Bupropion is extensively metabolized in humans. Oxidation of the bupropion side chain results in the formation of a glycine conjugate of metachlorobenzoic acid, which is then excreted as the major urinary metabolite. Following oral administration of 200 mg of 14C-bupropion in humans, 87% and 10% of the radioactive dose were recovered in the urine and feces, respectively. However, the fraction of the oral dose of bupropion excreted unchanged was only 0.5%, a finding consistent with the extensive metabolism of bupropion. •Route of elimination (Drug B): One molecule of sodium nitroprusside is metabolized by combination with hemoglobin to produce one molecule of cyanmethemoglobin and four CN¯ ions, thiosulfate reacts with cyanide to produce thiocyanate, thiocyanate is eliminated in the urine. •Half-life (Drug A): 24 hours •Half-life (Drug B): Approximately 2 minutes •Clearance (Drug A): No clearance available •Clearance (Drug B): No clearance available •Toxicity (Drug A): Symptoms of overdose include seizures, hallucinations, loss of consciousness, tachycardia, and cardiac arrest. •Toxicity (Drug B): Overdosage of nitroprusside can be manifested as excessive hypotension or cyanide toxicity or as thiocyanate toxicity. The acute intravenous mean lethal doses (LD 50 ) of nitroprusside in rabbits, dogs, mice, and rats are 2.8, 5.0, 8.4, and 11.2 mg/kg, respectively. •Brand Names (Drug A): Aplenzin, Auvelity, Budeprion, Contrave, Forfivo, Wellbutrin, Zyban •Brand Names (Drug B): Nipride, Nipride RTU, Nitropress •Synonyms (Drug A): No synonyms listed •Synonyms (Drug B): No synonyms listed •Summary (Drug A): Bupropion is a norepinephrine and dopamine reuptake inhibitor used in the treatment of major depressive disorder (MDD), seasonal affective disorder (SAD), and as an aid to smoking cessation. •Summary (Drug B): Nitroprusside is a direct acting vasodilator used to treat hypertension, to induce controlled hypotension to reduce postoperative bleeding, and to manage acute heart failure. Output: The renal excretion of drugs is the overall result of a combination of kidney processes that include glomerular filtration, passive diffusion, tubular secretion, and tubular reabsorption. Since two of these mechanisms - tubular secretion and reabsorption - are saturable processes , they are consequently susceptible to competition between multiple substrates excreted by the kidneys. If two or more medications that are mainly renally excreted are co-administered, they may compete for renal elimination; there is a large likelihood that one agent may "out-compete" or saturate the renal excretion mechanisms before the other concomitantly administered agent(s) are excreted. As a result, the elimination of these other concurrently administered agents may be inhibited or otherwise delayed, which could lead to increases in their serum concentrations and the risk, incidence, and/or severity of adverse effects associated with the exposure to such drugs. The severity of the interaction is minor.

Does Bupropion and Nitrous oxide interact?

•Drug A: Bupropion •Drug B: Nitrous oxide •Severity: MODERATE •Description: The risk or severity of CNS depression can be increased when Bupropion is combined with Nitrous oxide. •Extended Description: Central nervous system (CNS) depressants can cause sedation, falls, respiratory depression, coma, and death.2,3 The potential interaction between a CNS depressant and another CNS depressant drug due to synergistic effects is well documented in the literature, although the risk and severity of CNS depression vary from each drug. The subject and affected drugs are both CNS depressants that, when co-administered, may result in a more profound CNS depression. As the risk and severity of CNS depression resulting from the combined use of CNS depressants vary from each agent, each interaction between CNS depressants should be considered individually. •Indication (Drug A): Bupropion is indicated for the treatment of major depressive disorder (MDD), seasonal affective disorder (SAD), and as an aid to smoking cessation. When used in combination with naltrexone as the marketed product ContraveⓇ, bupropion is indicated as an adjunct to a reduced-calorie diet and increased physical activity for chronic weight management in adults with an initial body mass index (BMI) of: 30 kg/m^2 or greater (obese) or 27 kg/m^2 or greater (overweight) in the presence of at least one weight-related comorbid condition (e.g., hypertension, type 2 diabetes mellitus, or dyslipidemia). Bupropion is also used off-label as a first-line treatment in patients with ADHD and comorbid bipolar disorder when used as an adjunct to mood stabilizers. •Indication (Drug B): No indication available •Pharmacodynamics (Drug A): Bupropion is chemically unrelated to tricyclic, tetracyclic, selective serotonin re-uptake inhibitors, or other known antidepressant agents. Compared to classical tricyclic antidepressants, Bupropion is a relatively weak inhibitor of the neuronal uptake of norepinephrine and dopamine. In addition, Bupropion does not inhibit monoamine oxidase. Bupropion has been found to be essentially inactive at the serotonin transporter (SERT)(IC50 >10 000 nM), however both bupropion and its primary metabolite hydroxybupropion have been found to block the function of cation-selective serotonin type 3A receptors (5-HT3ARs). Bupropion produces dose-related central nervous system (CNS) stimulant effects in animals, as evidenced by increased locomotor activity, increased rates of responding in various schedule-controlled operant behaviour tasks, and, at high doses, induction of mild stereotyped behaviour. Due to these stimulant effects and selective activity at dopamine and norepinephrine receptors, bupropion has been identified as having an abuse potential. Bupropion has a similar structure to the controlled substance Cathinone, and has been identified as having mild amphetamine-like activity, particularly when inhaled or injected. Bupropion is also known to lower the seizure threshold, making any pre-existing seizure conditions a contraindication to its use. This risk is exacerbated when bupropion is combined with other drugs or substances that lower the seizure threshold, such as cocaine, or in clinical situations that would increase the risk of a seizure such as abrupt alcohol or benzodiazepine withdrawal. As norepinephrine has been shown to have anticonvulsant properties, bupropion's inhibitory effects on NET are thought to contribute to its pro-convulsant activity. Bupropion has been shown to increase blood pressure and pose a risk for exacerbation of unmanaged or pre-existing hypertension, however, clinical trials of bupropion in smokers with CVD have not identified an increased incidence of CV events including stroke or heart attack. In clinical trials, the mean increase in systolic blood pressure associated with the use of bupropion was found to be 1.3 mmHg. •Pharmacodynamics (Drug B): No pharmacodynamics available •Mechanism of action (Drug A): Bupropion is a norepinephrine/dopamine-reuptake inhibitor (NDRI) that exerts its pharmacological effects by weakly inhibiting the enzymes involved in the uptake of the neurotransmitters norepinephrine and dopamine from the synaptic cleft, therefore prolonging their duration of action within the neuronal synapse and the downstream effects of these neurotransmitters. More specifically, bupropion binds to the norepinephrine transporter (NET) and the dopamine transporter (DAT). Bupropion was originally classified as an "atypical" antidepressant because it does not exert the same effects as the classical antidepressants such as Monoamine Oxidase Inhibitors (MAOIs), Tricyclic Antidepressants (TCAs), or Selective Serotonin Reuptake Inhibitors (SSRIs). While it has comparable effectiveness to typical first-line options for the treatment of depression such as SSRIs, bupropion is a unique option for the treatment of MDD as it lacks any clinically relevant serotonergic effects, typical of other mood medications, or any effects on histamine or adrenaline receptors. Lack of activity at these receptors results in a more tolerable side effect profile; bupropion is less likely to cause sexual side effects, sedation, or weight gain as compared to SSRIs or TCAs, for example. When used as an aid to smoking cessation, bupropion is thought to confer its anti-craving and anti-withdrawal effects by inhibiting dopamine reuptake, which is thought to be involved in the reward pathways associated with nicotine, and through the antagonism of the nicotinic acetylcholinergic receptor (AChR), thereby blunting the effects of nicotine. Furthermore, the stimulatory effects produced by bupropion in the central nervous system are similar to nicotine's effects, making low doses of bupropion a suitable option as a nicotine substitute. When used in combination with naltrexone in the marketed product ContraveⓇ for chronic weight management, the two components are thought to have effects on areas of the brain involved in the regulation of food intake. This includes the hypothalamus, which is involved in appetite regulation, and the mesolimbic dopamine circuit, which is involved in reward pathways. Studies have shown that the combined activity of bupropion and naltrexone increase the firing rate of hypothalamic pro-opiomelanocortin (POMC) neurons and blockade of opioid receptor-mediated POMC auto-inhibition, which are associated with a reduction in food intake and increased energy expenditure. This combination was also found to reduce food intake when injected directly into the ventral tegmental area of the mesolimbic circuit in mice, which is an area associated with the regulation of reward pathways. •Mechanism of action (Drug B): Findings to date indicate that nitrous oxide induces opioid peptide release in the brain stem leading to the activation of descending noradrenergic neurones, which results in modulation of the nociceptive process in the spinal cord. Several receptor–effector mechanisms including dopamine receptors, α2 adrenoceptors, benzodiazepine receptors and -methyl- -aspartate (NMDA) receptors have been implicated although the relationship of one with the other is not known. •Absorption (Drug A): Bupropion is currently available in 3 distinct, but bioequivalent formulations: immediate release (IR), sustained-release (SR), and extended-release (XL). Immediate Release Formulation In humans, following oral administration of bupropion hydrochloride tablets, peak plasma bupropion concentrations are usually achieved within 2 hours. IR formulations provide a short duration of action and are therefore generally dosed three times per day. Sustained Release Formulation In humans, following oral administration of bupropion hydrochloride sustained-release tablets (SR), peak plasma concentration (Cmax) of bupropion is usually achieved within 3 hours. SR formulations provide a 12-hour extended release of medication and are therefore generally dosed twice per day. Extended Release Formulation Following single oral administration of bupropion hydrochloride extended-release tablets (XL) to healthy volunteers, the median time to peak plasma concentrations for bupropion was approximately 5 hours. The presence of food did not affect the peak concentration or area under the curve of bupropion. XL formulations provide a 24-hour extended release of medication and are therefore generally dosed once per day/ In a trial comparing chronic dosing with bupropion hydrochloride extended-release tablets (SR) 150 mg twice daily to bupropion immediate-release formulation 100 mg 3 times daily, the steady state Cmax for bupropion after bupropion hydrochloride sustained-release tablets (SR) administration was approximately 85% of those achieved after bupropion immediate-release formulation administration. Exposure (AUC) to bupropion was equivalent for both formulations. Bioequivalence was also demonstrated for all three major active metabolites (i.e., hydroxybupropion, threohydrobupropion and erythrohydrobupropion) for both Cmax and AUC. Thus, at steady state, bupropion hydrochloride sustained-release tablets (SR) given twice daily, and the immediate-release formulation of bupropion given 3 times daily, are essentially bioequivalent for both bupropion and the 3 quantitatively important metabolites. Furthermore, in a study comparing 14-day dosing with bupropion hydrochloride extended-release tablets (XL), 300 mg once-daily to the immediate-release formulation of bupropion at 100 mg 3 times daily, equivalence was demonstrated for peak plasma concentration and area under the curve for bupropion and the three metabolites (hydroxybupropion, threohydrobupropion, and erythrohydrobupropion). Additionally, in a study comparing 14-day dosing with bupropion hydrochloride extended-release tablets (XL) 300 mg once daily to the sustained-release formulation of bupropion at 150 mg 2 times daily, equivalence was demonstrated for peak plasma concentration and area under the curve for bupropion and the three metabolites. Bupropion hydrochloride extended-release tablets (SR) can be taken with or without food. Bupropion Cmax and AUC were increased by 11% to 35% and 16% to 19%, respectively, when bupropion hydrochloride extended-release tablets (SR) was administered with food to healthy volunteers in three trials. The food effect is not considered clinically significant. Following a single-dose administration of bupropion hydrochloride extended-release tablets (SR) in humans, Cmax of bupropion's metabolite hydroxybupropion occurs approximately 6 hours post-dose and is approximately 10 times the peak level of the parent drug at steady state. The elimination half-life of hydroxybupropion is approximately 20 (±5) hours and its AUC at steady state is about 17 times that of bupropion. The times to peak concentrations for the erythrohydrobupropion and threohydrobupropion metabolites are similar to that of the hydroxybupropion metabolite. However, their elimination half-lives are longer, 33(±10) and 37 (±13) hours, respectively, and steady-state AUCs are 1.5 and 7 times that of bupropion, respectively. •Absorption (Drug B): No absorption available •Volume of distribution (Drug A): No volume of distribution available •Volume of distribution (Drug B): No volume of distribution available •Protein binding (Drug A): In vitro tests show that bupropion is 84% bound to human plasma proteins at concentrations up to 200 mcg per mL. The extent of protein binding of the hydroxybupropion metabolite is similar to that for bupropion, whereas the extent of protein binding of the threohydrobupropion metabolite is about half that seen with bupropion. •Protein binding (Drug B): No protein binding available •Metabolism (Drug A): Bupropion is extensively metabolized in humans. Three metabolites are active: hydroxybupropion, which is formed via hydroxylation of the tert-butyl group of bupropion, and the amino-alcohol isomers, threohydrobupropion and erythrohydrobupropion, which are formed via reduction of the carbonyl group. In vitro findings suggest that CYP2B6 is the principal isoenzyme involved in the formation of hydroxybupropion, while cytochrome P450 enzymes are not involved in the formation of threohydrobupropion. Hydroxybupropion has been shown to have the same affinity as bupropion for the norepinephrine transporter (NET) but approximately 50% of its antidepressant activity despite reaching concentrations of ~10-fold higher than that of the parent drug. Oxidation of the bupropion side chain results in the formation of a glycine conjugate of meta-chlorobenzoic acid, which is then excreted as the major urinary metabolite. The potency and toxicity of the metabolites relative to bupropion have not been fully characterized. However, it has been demonstrated in an antidepressant screening test in mice that hydroxybupropion is one-half as potent as bupropion, while threohydrobupropion and erythrohydrobupropion are 5-fold less potent than bupropion. This may be of clinical importance because the plasma concentrations of the metabolites are as high as or higher than those of bupropion. Bupropion and its metabolites exhibit linear kinetics following chronic administration of 300 to 450 mg per day. •Metabolism (Drug B): No metabolism available •Route of elimination (Drug A): Bupropion is extensively metabolized in humans. Oxidation of the bupropion side chain results in the formation of a glycine conjugate of metachlorobenzoic acid, which is then excreted as the major urinary metabolite. Following oral administration of 200 mg of 14C-bupropion in humans, 87% and 10% of the radioactive dose were recovered in the urine and feces, respectively. However, the fraction of the oral dose of bupropion excreted unchanged was only 0.5%, a finding consistent with the extensive metabolism of bupropion. •Route of elimination (Drug B): No route of elimination available •Half-life (Drug A): 24 hours •Half-life (Drug B): No half-life available •Clearance (Drug A): No clearance available •Clearance (Drug B): No clearance available •Toxicity (Drug A): Symptoms of overdose include seizures, hallucinations, loss of consciousness, tachycardia, and cardiac arrest. •Toxicity (Drug B): No toxicity available •Brand Names (Drug A): Aplenzin, Auvelity, Budeprion, Contrave, Forfivo, Wellbutrin, Zyban •Brand Names (Drug B): Alnox •Synonyms (Drug A): No synonyms listed •Synonyms (Drug B): Dinitrogen oxide Nitrious oxide Nitrous oxide óxido nitroso •Summary (Drug A): Bupropion is a norepinephrine and dopamine reuptake inhibitor used in the treatment of major depressive disorder (MDD), seasonal affective disorder (SAD), and as an aid to smoking cessation. •Summary (Drug B): Nitrous oxide is an inhalatory gas used as an adjunct to improve oxygenation and reduce the need for extracorporeal membrane oxygenation in certain neonates with hypoxic respiratory failure.

Central nervous system (CNS) depressants can cause sedation, falls, respiratory depression, coma, and death.2,3 The potential interaction between a CNS depressant and another CNS depressant drug due to synergistic effects is well documented in the literature, although the risk and severity of CNS depression vary from each drug. The subject and affected drugs are both CNS depressants that, when co-administered, may result in a more profound CNS depression. As the risk and severity of CNS depression resulting from the combined use of CNS depressants vary from each agent, each interaction between CNS depressants should be considered individually. The severity of the interaction is moderate.

Question: Does Bupropion and Nitrous oxide interact? Information: •Drug A: Bupropion •Drug B: Nitrous oxide •Severity: MODERATE •Description: The risk or severity of CNS depression can be increased when Bupropion is combined with Nitrous oxide. •Extended Description: Central nervous system (CNS) depressants can cause sedation, falls, respiratory depression, coma, and death.2,3 The potential interaction between a CNS depressant and another CNS depressant drug due to synergistic effects is well documented in the literature, although the risk and severity of CNS depression vary from each drug. The subject and affected drugs are both CNS depressants that, when co-administered, may result in a more profound CNS depression. As the risk and severity of CNS depression resulting from the combined use of CNS depressants vary from each agent, each interaction between CNS depressants should be considered individually. •Indication (Drug A): Bupropion is indicated for the treatment of major depressive disorder (MDD), seasonal affective disorder (SAD), and as an aid to smoking cessation. When used in combination with naltrexone as the marketed product ContraveⓇ, bupropion is indicated as an adjunct to a reduced-calorie diet and increased physical activity for chronic weight management in adults with an initial body mass index (BMI) of: 30 kg/m^2 or greater (obese) or 27 kg/m^2 or greater (overweight) in the presence of at least one weight-related comorbid condition (e.g., hypertension, type 2 diabetes mellitus, or dyslipidemia). Bupropion is also used off-label as a first-line treatment in patients with ADHD and comorbid bipolar disorder when used as an adjunct to mood stabilizers. •Indication (Drug B): No indication available •Pharmacodynamics (Drug A): Bupropion is chemically unrelated to tricyclic, tetracyclic, selective serotonin re-uptake inhibitors, or other known antidepressant agents. Compared to classical tricyclic antidepressants, Bupropion is a relatively weak inhibitor of the neuronal uptake of norepinephrine and dopamine. In addition, Bupropion does not inhibit monoamine oxidase. Bupropion has been found to be essentially inactive at the serotonin transporter (SERT)(IC50 >10 000 nM), however both bupropion and its primary metabolite hydroxybupropion have been found to block the function of cation-selective serotonin type 3A receptors (5-HT3ARs). Bupropion produces dose-related central nervous system (CNS) stimulant effects in animals, as evidenced by increased locomotor activity, increased rates of responding in various schedule-controlled operant behaviour tasks, and, at high doses, induction of mild stereotyped behaviour. Due to these stimulant effects and selective activity at dopamine and norepinephrine receptors, bupropion has been identified as having an abuse potential. Bupropion has a similar structure to the controlled substance Cathinone, and has been identified as having mild amphetamine-like activity, particularly when inhaled or injected. Bupropion is also known to lower the seizure threshold, making any pre-existing seizure conditions a contraindication to its use. This risk is exacerbated when bupropion is combined with other drugs or substances that lower the seizure threshold, such as cocaine, or in clinical situations that would increase the risk of a seizure such as abrupt alcohol or benzodiazepine withdrawal. As norepinephrine has been shown to have anticonvulsant properties, bupropion's inhibitory effects on NET are thought to contribute to its pro-convulsant activity. Bupropion has been shown to increase blood pressure and pose a risk for exacerbation of unmanaged or pre-existing hypertension, however, clinical trials of bupropion in smokers with CVD have not identified an increased incidence of CV events including stroke or heart attack. In clinical trials, the mean increase in systolic blood pressure associated with the use of bupropion was found to be 1.3 mmHg. •Pharmacodynamics (Drug B): No pharmacodynamics available •Mechanism of action (Drug A): Bupropion is a norepinephrine/dopamine-reuptake inhibitor (NDRI) that exerts its pharmacological effects by weakly inhibiting the enzymes involved in the uptake of the neurotransmitters norepinephrine and dopamine from the synaptic cleft, therefore prolonging their duration of action within the neuronal synapse and the downstream effects of these neurotransmitters. More specifically, bupropion binds to the norepinephrine transporter (NET) and the dopamine transporter (DAT). Bupropion was originally classified as an "atypical" antidepressant because it does not exert the same effects as the classical antidepressants such as Monoamine Oxidase Inhibitors (MAOIs), Tricyclic Antidepressants (TCAs), or Selective Serotonin Reuptake Inhibitors (SSRIs). While it has comparable effectiveness to typical first-line options for the treatment of depression such as SSRIs, bupropion is a unique option for the treatment of MDD as it lacks any clinically relevant serotonergic effects, typical of other mood medications, or any effects on histamine or adrenaline receptors. Lack of activity at these receptors results in a more tolerable side effect profile; bupropion is less likely to cause sexual side effects, sedation, or weight gain as compared to SSRIs or TCAs, for example. When used as an aid to smoking cessation, bupropion is thought to confer its anti-craving and anti-withdrawal effects by inhibiting dopamine reuptake, which is thought to be involved in the reward pathways associated with nicotine, and through the antagonism of the nicotinic acetylcholinergic receptor (AChR), thereby blunting the effects of nicotine. Furthermore, the stimulatory effects produced by bupropion in the central nervous system are similar to nicotine's effects, making low doses of bupropion a suitable option as a nicotine substitute. When used in combination with naltrexone in the marketed product ContraveⓇ for chronic weight management, the two components are thought to have effects on areas of the brain involved in the regulation of food intake. This includes the hypothalamus, which is involved in appetite regulation, and the mesolimbic dopamine circuit, which is involved in reward pathways. Studies have shown that the combined activity of bupropion and naltrexone increase the firing rate of hypothalamic pro-opiomelanocortin (POMC) neurons and blockade of opioid receptor-mediated POMC auto-inhibition, which are associated with a reduction in food intake and increased energy expenditure. This combination was also found to reduce food intake when injected directly into the ventral tegmental area of the mesolimbic circuit in mice, which is an area associated with the regulation of reward pathways. •Mechanism of action (Drug B): Findings to date indicate that nitrous oxide induces opioid peptide release in the brain stem leading to the activation of descending noradrenergic neurones, which results in modulation of the nociceptive process in the spinal cord. Several receptor–effector mechanisms including dopamine receptors, α2 adrenoceptors, benzodiazepine receptors and -methyl- -aspartate (NMDA) receptors have been implicated although the relationship of one with the other is not known. •Absorption (Drug A): Bupropion is currently available in 3 distinct, but bioequivalent formulations: immediate release (IR), sustained-release (SR), and extended-release (XL). Immediate Release Formulation In humans, following oral administration of bupropion hydrochloride tablets, peak plasma bupropion concentrations are usually achieved within 2 hours. IR formulations provide a short duration of action and are therefore generally dosed three times per day. Sustained Release Formulation In humans, following oral administration of bupropion hydrochloride sustained-release tablets (SR), peak plasma concentration (Cmax) of bupropion is usually achieved within 3 hours. SR formulations provide a 12-hour extended release of medication and are therefore generally dosed twice per day. Extended Release Formulation Following single oral administration of bupropion hydrochloride extended-release tablets (XL) to healthy volunteers, the median time to peak plasma concentrations for bupropion was approximately 5 hours. The presence of food did not affect the peak concentration or area under the curve of bupropion. XL formulations provide a 24-hour extended release of medication and are therefore generally dosed once per day/ In a trial comparing chronic dosing with bupropion hydrochloride extended-release tablets (SR) 150 mg twice daily to bupropion immediate-release formulation 100 mg 3 times daily, the steady state Cmax for bupropion after bupropion hydrochloride sustained-release tablets (SR) administration was approximately 85% of those achieved after bupropion immediate-release formulation administration. Exposure (AUC) to bupropion was equivalent for both formulations. Bioequivalence was also demonstrated for all three major active metabolites (i.e., hydroxybupropion, threohydrobupropion and erythrohydrobupropion) for both Cmax and AUC. Thus, at steady state, bupropion hydrochloride sustained-release tablets (SR) given twice daily, and the immediate-release formulation of bupropion given 3 times daily, are essentially bioequivalent for both bupropion and the 3 quantitatively important metabolites. Furthermore, in a study comparing 14-day dosing with bupropion hydrochloride extended-release tablets (XL), 300 mg once-daily to the immediate-release formulation of bupropion at 100 mg 3 times daily, equivalence was demonstrated for peak plasma concentration and area under the curve for bupropion and the three metabolites (hydroxybupropion, threohydrobupropion, and erythrohydrobupropion). Additionally, in a study comparing 14-day dosing with bupropion hydrochloride extended-release tablets (XL) 300 mg once daily to the sustained-release formulation of bupropion at 150 mg 2 times daily, equivalence was demonstrated for peak plasma concentration and area under the curve for bupropion and the three metabolites. Bupropion hydrochloride extended-release tablets (SR) can be taken with or without food. Bupropion Cmax and AUC were increased by 11% to 35% and 16% to 19%, respectively, when bupropion hydrochloride extended-release tablets (SR) was administered with food to healthy volunteers in three trials. The food effect is not considered clinically significant. Following a single-dose administration of bupropion hydrochloride extended-release tablets (SR) in humans, Cmax of bupropion's metabolite hydroxybupropion occurs approximately 6 hours post-dose and is approximately 10 times the peak level of the parent drug at steady state. The elimination half-life of hydroxybupropion is approximately 20 (±5) hours and its AUC at steady state is about 17 times that of bupropion. The times to peak concentrations for the erythrohydrobupropion and threohydrobupropion metabolites are similar to that of the hydroxybupropion metabolite. However, their elimination half-lives are longer, 33(±10) and 37 (±13) hours, respectively, and steady-state AUCs are 1.5 and 7 times that of bupropion, respectively. •Absorption (Drug B): No absorption available •Volume of distribution (Drug A): No volume of distribution available •Volume of distribution (Drug B): No volume of distribution available •Protein binding (Drug A): In vitro tests show that bupropion is 84% bound to human plasma proteins at concentrations up to 200 mcg per mL. The extent of protein binding of the hydroxybupropion metabolite is similar to that for bupropion, whereas the extent of protein binding of the threohydrobupropion metabolite is about half that seen with bupropion. •Protein binding (Drug B): No protein binding available •Metabolism (Drug A): Bupropion is extensively metabolized in humans. Three metabolites are active: hydroxybupropion, which is formed via hydroxylation of the tert-butyl group of bupropion, and the amino-alcohol isomers, threohydrobupropion and erythrohydrobupropion, which are formed via reduction of the carbonyl group. In vitro findings suggest that CYP2B6 is the principal isoenzyme involved in the formation of hydroxybupropion, while cytochrome P450 enzymes are not involved in the formation of threohydrobupropion. Hydroxybupropion has been shown to have the same affinity as bupropion for the norepinephrine transporter (NET) but approximately 50% of its antidepressant activity despite reaching concentrations of ~10-fold higher than that of the parent drug. Oxidation of the bupropion side chain results in the formation of a glycine conjugate of meta-chlorobenzoic acid, which is then excreted as the major urinary metabolite. The potency and toxicity of the metabolites relative to bupropion have not been fully characterized. However, it has been demonstrated in an antidepressant screening test in mice that hydroxybupropion is one-half as potent as bupropion, while threohydrobupropion and erythrohydrobupropion are 5-fold less potent than bupropion. This may be of clinical importance because the plasma concentrations of the metabolites are as high as or higher than those of bupropion. Bupropion and its metabolites exhibit linear kinetics following chronic administration of 300 to 450 mg per day. •Metabolism (Drug B): No metabolism available •Route of elimination (Drug A): Bupropion is extensively metabolized in humans. Oxidation of the bupropion side chain results in the formation of a glycine conjugate of metachlorobenzoic acid, which is then excreted as the major urinary metabolite. Following oral administration of 200 mg of 14C-bupropion in humans, 87% and 10% of the radioactive dose were recovered in the urine and feces, respectively. However, the fraction of the oral dose of bupropion excreted unchanged was only 0.5%, a finding consistent with the extensive metabolism of bupropion. •Route of elimination (Drug B): No route of elimination available •Half-life (Drug A): 24 hours •Half-life (Drug B): No half-life available •Clearance (Drug A): No clearance available •Clearance (Drug B): No clearance available •Toxicity (Drug A): Symptoms of overdose include seizures, hallucinations, loss of consciousness, tachycardia, and cardiac arrest. •Toxicity (Drug B): No toxicity available •Brand Names (Drug A): Aplenzin, Auvelity, Budeprion, Contrave, Forfivo, Wellbutrin, Zyban •Brand Names (Drug B): Alnox •Synonyms (Drug A): No synonyms listed •Synonyms (Drug B): Dinitrogen oxide Nitrious oxide Nitrous oxide óxido nitroso •Summary (Drug A): Bupropion is a norepinephrine and dopamine reuptake inhibitor used in the treatment of major depressive disorder (MDD), seasonal affective disorder (SAD), and as an aid to smoking cessation. •Summary (Drug B): Nitrous oxide is an inhalatory gas used as an adjunct to improve oxygenation and reduce the need for extracorporeal membrane oxygenation in certain neonates with hypoxic respiratory failure. Output: Central nervous system (CNS) depressants can cause sedation, falls, respiratory depression, coma, and death.2,3 The potential interaction between a CNS depressant and another CNS depressant drug due to synergistic effects is well documented in the literature, although the risk and severity of CNS depression vary from each drug. The subject and affected drugs are both CNS depressants that, when co-administered, may result in a more profound CNS depression. As the risk and severity of CNS depression resulting from the combined use of CNS depressants vary from each agent, each interaction between CNS depressants should be considered individually. The severity of the interaction is moderate.

Does Bupropion and Norepinephrine interact?

•Drug A: Bupropion •Drug B: Norepinephrine •Severity: MODERATE •Description: The excretion of Norepinephrine can be decreased when combined with Bupropion. •Extended Description: Findings from in vitro studies showed that bupropion and its metabolites inhibit OCT2, suggesting that clinically relevant interaction through inhibition of OCT2 could occur at therapeutic bupropion doses. Co-administration of bupropion with OCT2 substrates may result in attenuated OCT2-mediated efflux of those drugs, thereby increasing drug serum concentrations. •Indication (Drug A): Bupropion is indicated for the treatment of major depressive disorder (MDD), seasonal affective disorder (SAD), and as an aid to smoking cessation. When used in combination with naltrexone as the marketed product ContraveⓇ, bupropion is indicated as an adjunct to a reduced-calorie diet and increased physical activity for chronic weight management in adults with an initial body mass index (BMI) of: 30 kg/m^2 or greater (obese) or 27 kg/m^2 or greater (overweight) in the presence of at least one weight-related comorbid condition (e.g., hypertension, type 2 diabetes mellitus, or dyslipidemia). Bupropion is also used off-label as a first-line treatment in patients with ADHD and comorbid bipolar disorder when used as an adjunct to mood stabilizers. •Indication (Drug B): Mainly used to treat patients in vasodilatory shock states such as septic shock and neurogenic shock and has shown a survival benefit over dopamine. Also used as a vasopressor medication for patients with critical hypotension. •Pharmacodynamics (Drug A): Bupropion is chemically unrelated to tricyclic, tetracyclic, selective serotonin re-uptake inhibitors, or other known antidepressant agents. Compared to classical tricyclic antidepressants, Bupropion is a relatively weak inhibitor of the neuronal uptake of norepinephrine and dopamine. In addition, Bupropion does not inhibit monoamine oxidase. Bupropion has been found to be essentially inactive at the serotonin transporter (SERT)(IC50 >10 000 nM), however both bupropion and its primary metabolite hydroxybupropion have been found to block the function of cation-selective serotonin type 3A receptors (5-HT3ARs). Bupropion produces dose-related central nervous system (CNS) stimulant effects in animals, as evidenced by increased locomotor activity, increased rates of responding in various schedule-controlled operant behaviour tasks, and, at high doses, induction of mild stereotyped behaviour. Due to these stimulant effects and selective activity at dopamine and norepinephrine receptors, bupropion has been identified as having an abuse potential. Bupropion has a similar structure to the controlled substance Cathinone, and has been identified as having mild amphetamine-like activity, particularly when inhaled or injected. Bupropion is also known to lower the seizure threshold, making any pre-existing seizure conditions a contraindication to its use. This risk is exacerbated when bupropion is combined with other drugs or substances that lower the seizure threshold, such as cocaine, or in clinical situations that would increase the risk of a seizure such as abrupt alcohol or benzodiazepine withdrawal. As norepinephrine has been shown to have anticonvulsant properties, bupropion's inhibitory effects on NET are thought to contribute to its pro-convulsant activity. Bupropion has been shown to increase blood pressure and pose a risk for exacerbation of unmanaged or pre-existing hypertension, however, clinical trials of bupropion in smokers with CVD have not identified an increased incidence of CV events including stroke or heart attack. In clinical trials, the mean increase in systolic blood pressure associated with the use of bupropion was found to be 1.3 mmHg. •Pharmacodynamics (Drug B): Noradrenaline acts on both alpha-1 and alpha-2 adrenergic receptors to cause vasoconstriction. Its effect in-vitro is often limited to the increasing of blood pressure through antagonising alpha-1 and alpha-2 receptors and causing a resultant increase in systemic vascular resistance. •Mechanism of action (Drug A): Bupropion is a norepinephrine/dopamine-reuptake inhibitor (NDRI) that exerts its pharmacological effects by weakly inhibiting the enzymes involved in the uptake of the neurotransmitters norepinephrine and dopamine from the synaptic cleft, therefore prolonging their duration of action within the neuronal synapse and the downstream effects of these neurotransmitters. More specifically, bupropion binds to the norepinephrine transporter (NET) and the dopamine transporter (DAT). Bupropion was originally classified as an "atypical" antidepressant because it does not exert the same effects as the classical antidepressants such as Monoamine Oxidase Inhibitors (MAOIs), Tricyclic Antidepressants (TCAs), or Selective Serotonin Reuptake Inhibitors (SSRIs). While it has comparable effectiveness to typical first-line options for the treatment of depression such as SSRIs, bupropion is a unique option for the treatment of MDD as it lacks any clinically relevant serotonergic effects, typical of other mood medications, or any effects on histamine or adrenaline receptors. Lack of activity at these receptors results in a more tolerable side effect profile; bupropion is less likely to cause sexual side effects, sedation, or weight gain as compared to SSRIs or TCAs, for example. When used as an aid to smoking cessation, bupropion is thought to confer its anti-craving and anti-withdrawal effects by inhibiting dopamine reuptake, which is thought to be involved in the reward pathways associated with nicotine, and through the antagonism of the nicotinic acetylcholinergic receptor (AChR), thereby blunting the effects of nicotine. Furthermore, the stimulatory effects produced by bupropion in the central nervous system are similar to nicotine's effects, making low doses of bupropion a suitable option as a nicotine substitute. When used in combination with naltrexone in the marketed product ContraveⓇ for chronic weight management, the two components are thought to have effects on areas of the brain involved in the regulation of food intake. This includes the hypothalamus, which is involved in appetite regulation, and the mesolimbic dopamine circuit, which is involved in reward pathways. Studies have shown that the combined activity of bupropion and naltrexone increase the firing rate of hypothalamic pro-opiomelanocortin (POMC) neurons and blockade of opioid receptor-mediated POMC auto-inhibition, which are associated with a reduction in food intake and increased energy expenditure. This combination was also found to reduce food intake when injected directly into the ventral tegmental area of the mesolimbic circuit in mice, which is an area associated with the regulation of reward pathways. •Mechanism of action (Drug B): Norepinephrine functions as a peripheral vasoconstrictor by acting on alpha-adrenergic receptors. It is also an inotropic stimulator of the heart and dilator of coronary arteries as a result of it's activity at the beta-adrenergic receptors. •Absorption (Drug A): Bupropion is currently available in 3 distinct, but bioequivalent formulations: immediate release (IR), sustained-release (SR), and extended-release (XL). Immediate Release Formulation In humans, following oral administration of bupropion hydrochloride tablets, peak plasma bupropion concentrations are usually achieved within 2 hours. IR formulations provide a short duration of action and are therefore generally dosed three times per day. Sustained Release Formulation In humans, following oral administration of bupropion hydrochloride sustained-release tablets (SR), peak plasma concentration (Cmax) of bupropion is usually achieved within 3 hours. SR formulations provide a 12-hour extended release of medication and are therefore generally dosed twice per day. Extended Release Formulation Following single oral administration of bupropion hydrochloride extended-release tablets (XL) to healthy volunteers, the median time to peak plasma concentrations for bupropion was approximately 5 hours. The presence of food did not affect the peak concentration or area under the curve of bupropion. XL formulations provide a 24-hour extended release of medication and are therefore generally dosed once per day/ In a trial comparing chronic dosing with bupropion hydrochloride extended-release tablets (SR) 150 mg twice daily to bupropion immediate-release formulation 100 mg 3 times daily, the steady state Cmax for bupropion after bupropion hydrochloride sustained-release tablets (SR) administration was approximately 85% of those achieved after bupropion immediate-release formulation administration. Exposure (AUC) to bupropion was equivalent for both formulations. Bioequivalence was also demonstrated for all three major active metabolites (i.e., hydroxybupropion, threohydrobupropion and erythrohydrobupropion) for both Cmax and AUC. Thus, at steady state, bupropion hydrochloride sustained-release tablets (SR) given twice daily, and the immediate-release formulation of bupropion given 3 times daily, are essentially bioequivalent for both bupropion and the 3 quantitatively important metabolites. Furthermore, in a study comparing 14-day dosing with bupropion hydrochloride extended-release tablets (XL), 300 mg once-daily to the immediate-release formulation of bupropion at 100 mg 3 times daily, equivalence was demonstrated for peak plasma concentration and area under the curve for bupropion and the three metabolites (hydroxybupropion, threohydrobupropion, and erythrohydrobupropion). Additionally, in a study comparing 14-day dosing with bupropion hydrochloride extended-release tablets (XL) 300 mg once daily to the sustained-release formulation of bupropion at 150 mg 2 times daily, equivalence was demonstrated for peak plasma concentration and area under the curve for bupropion and the three metabolites. Bupropion hydrochloride extended-release tablets (SR) can be taken with or without food. Bupropion Cmax and AUC were increased by 11% to 35% and 16% to 19%, respectively, when bupropion hydrochloride extended-release tablets (SR) was administered with food to healthy volunteers in three trials. The food effect is not considered clinically significant. Following a single-dose administration of bupropion hydrochloride extended-release tablets (SR) in humans, Cmax of bupropion's metabolite hydroxybupropion occurs approximately 6 hours post-dose and is approximately 10 times the peak level of the parent drug at steady state. The elimination half-life of hydroxybupropion is approximately 20 (±5) hours and its AUC at steady state is about 17 times that of bupropion. The times to peak concentrations for the erythrohydrobupropion and threohydrobupropion metabolites are similar to that of the hydroxybupropion metabolite. However, their elimination half-lives are longer, 33(±10) and 37 (±13) hours, respectively, and steady-state AUCs are 1.5 and 7 times that of bupropion, respectively. •Absorption (Drug B): No absorption available •Volume of distribution (Drug A): No volume of distribution available •Volume of distribution (Drug B): No volume of distribution available •Protein binding (Drug A): In vitro tests show that bupropion is 84% bound to human plasma proteins at concentrations up to 200 mcg per mL. The extent of protein binding of the hydroxybupropion metabolite is similar to that for bupropion, whereas the extent of protein binding of the threohydrobupropion metabolite is about half that seen with bupropion. •Protein binding (Drug B): No protein binding available •Metabolism (Drug A): Bupropion is extensively metabolized in humans. Three metabolites are active: hydroxybupropion, which is formed via hydroxylation of the tert-butyl group of bupropion, and the amino-alcohol isomers, threohydrobupropion and erythrohydrobupropion, which are formed via reduction of the carbonyl group. In vitro findings suggest that CYP2B6 is the principal isoenzyme involved in the formation of hydroxybupropion, while cytochrome P450 enzymes are not involved in the formation of threohydrobupropion. Hydroxybupropion has been shown to have the same affinity as bupropion for the norepinephrine transporter (NET) but approximately 50% of its antidepressant activity despite reaching concentrations of ~10-fold higher than that of the parent drug. Oxidation of the bupropion side chain results in the formation of a glycine conjugate of meta-chlorobenzoic acid, which is then excreted as the major urinary metabolite. The potency and toxicity of the metabolites relative to bupropion have not been fully characterized. However, it has been demonstrated in an antidepressant screening test in mice that hydroxybupropion is one-half as potent as bupropion, while threohydrobupropion and erythrohydrobupropion are 5-fold less potent than bupropion. This may be of clinical importance because the plasma concentrations of the metabolites are as high as or higher than those of bupropion. Bupropion and its metabolites exhibit linear kinetics following chronic administration of 300 to 450 mg per day. •Metabolism (Drug B): No metabolism available •Route of elimination (Drug A): Bupropion is extensively metabolized in humans. Oxidation of the bupropion side chain results in the formation of a glycine conjugate of metachlorobenzoic acid, which is then excreted as the major urinary metabolite. Following oral administration of 200 mg of 14C-bupropion in humans, 87% and 10% of the radioactive dose were recovered in the urine and feces, respectively. However, the fraction of the oral dose of bupropion excreted unchanged was only 0.5%, a finding consistent with the extensive metabolism of bupropion. •Route of elimination (Drug B): No route of elimination available •Half-life (Drug A): 24 hours •Half-life (Drug B): No half-life available •Clearance (Drug A): No clearance available •Clearance (Drug B): No clearance available •Toxicity (Drug A): Symptoms of overdose include seizures, hallucinations, loss of consciousness, tachycardia, and cardiac arrest. •Toxicity (Drug B): In high dose and especially when it is combined with other vasopressors, it can lead to limb ischemia and limb death. •Brand Names (Drug A): Aplenzin, Auvelity, Budeprion, Contrave, Forfivo, Wellbutrin, Zyban •Brand Names (Drug B): Levophed •Synonyms (Drug A): No synonyms listed •Synonyms (Drug B): (R)-noradrenaline (R)-norepinephrine Arterenol L-noradrenaline L-Norepinephrine Nor-adrenaline Noradrenaline Norepinefrina Norepinephrine Norépinéphrine Norepinephrinum •Summary (Drug A): Bupropion is a norepinephrine and dopamine reuptake inhibitor used in the treatment of major depressive disorder (MDD), seasonal affective disorder (SAD), and as an aid to smoking cessation. •Summary (Drug B): Norepinephrine is a sympathomimetic used in the control of blood pressure during various hypotensive states and as an adjunct treatment during cardiac arrest.

Findings from in vitro studies showed that bupropion and its metabolites inhibit OCT2, suggesting that clinically relevant interaction through inhibition of OCT2 could occur at therapeutic bupropion doses. Co-administration of bupropion with OCT2 substrates may result in attenuated OCT2-mediated efflux of those drugs, thereby increasing drug serum concentrations. The severity of the interaction is moderate.

Question: Does Bupropion and Norepinephrine interact? Information: •Drug A: Bupropion •Drug B: Norepinephrine •Severity: MODERATE •Description: The excretion of Norepinephrine can be decreased when combined with Bupropion. •Extended Description: Findings from in vitro studies showed that bupropion and its metabolites inhibit OCT2, suggesting that clinically relevant interaction through inhibition of OCT2 could occur at therapeutic bupropion doses. Co-administration of bupropion with OCT2 substrates may result in attenuated OCT2-mediated efflux of those drugs, thereby increasing drug serum concentrations. •Indication (Drug A): Bupropion is indicated for the treatment of major depressive disorder (MDD), seasonal affective disorder (SAD), and as an aid to smoking cessation. When used in combination with naltrexone as the marketed product ContraveⓇ, bupropion is indicated as an adjunct to a reduced-calorie diet and increased physical activity for chronic weight management in adults with an initial body mass index (BMI) of: 30 kg/m^2 or greater (obese) or 27 kg/m^2 or greater (overweight) in the presence of at least one weight-related comorbid condition (e.g., hypertension, type 2 diabetes mellitus, or dyslipidemia). Bupropion is also used off-label as a first-line treatment in patients with ADHD and comorbid bipolar disorder when used as an adjunct to mood stabilizers. •Indication (Drug B): Mainly used to treat patients in vasodilatory shock states such as septic shock and neurogenic shock and has shown a survival benefit over dopamine. Also used as a vasopressor medication for patients with critical hypotension. •Pharmacodynamics (Drug A): Bupropion is chemically unrelated to tricyclic, tetracyclic, selective serotonin re-uptake inhibitors, or other known antidepressant agents. Compared to classical tricyclic antidepressants, Bupropion is a relatively weak inhibitor of the neuronal uptake of norepinephrine and dopamine. In addition, Bupropion does not inhibit monoamine oxidase. Bupropion has been found to be essentially inactive at the serotonin transporter (SERT)(IC50 >10 000 nM), however both bupropion and its primary metabolite hydroxybupropion have been found to block the function of cation-selective serotonin type 3A receptors (5-HT3ARs). Bupropion produces dose-related central nervous system (CNS) stimulant effects in animals, as evidenced by increased locomotor activity, increased rates of responding in various schedule-controlled operant behaviour tasks, and, at high doses, induction of mild stereotyped behaviour. Due to these stimulant effects and selective activity at dopamine and norepinephrine receptors, bupropion has been identified as having an abuse potential. Bupropion has a similar structure to the controlled substance Cathinone, and has been identified as having mild amphetamine-like activity, particularly when inhaled or injected. Bupropion is also known to lower the seizure threshold, making any pre-existing seizure conditions a contraindication to its use. This risk is exacerbated when bupropion is combined with other drugs or substances that lower the seizure threshold, such as cocaine, or in clinical situations that would increase the risk of a seizure such as abrupt alcohol or benzodiazepine withdrawal. As norepinephrine has been shown to have anticonvulsant properties, bupropion's inhibitory effects on NET are thought to contribute to its pro-convulsant activity. Bupropion has been shown to increase blood pressure and pose a risk for exacerbation of unmanaged or pre-existing hypertension, however, clinical trials of bupropion in smokers with CVD have not identified an increased incidence of CV events including stroke or heart attack. In clinical trials, the mean increase in systolic blood pressure associated with the use of bupropion was found to be 1.3 mmHg. •Pharmacodynamics (Drug B): Noradrenaline acts on both alpha-1 and alpha-2 adrenergic receptors to cause vasoconstriction. Its effect in-vitro is often limited to the increasing of blood pressure through antagonising alpha-1 and alpha-2 receptors and causing a resultant increase in systemic vascular resistance. •Mechanism of action (Drug A): Bupropion is a norepinephrine/dopamine-reuptake inhibitor (NDRI) that exerts its pharmacological effects by weakly inhibiting the enzymes involved in the uptake of the neurotransmitters norepinephrine and dopamine from the synaptic cleft, therefore prolonging their duration of action within the neuronal synapse and the downstream effects of these neurotransmitters. More specifically, bupropion binds to the norepinephrine transporter (NET) and the dopamine transporter (DAT). Bupropion was originally classified as an "atypical" antidepressant because it does not exert the same effects as the classical antidepressants such as Monoamine Oxidase Inhibitors (MAOIs), Tricyclic Antidepressants (TCAs), or Selective Serotonin Reuptake Inhibitors (SSRIs). While it has comparable effectiveness to typical first-line options for the treatment of depression such as SSRIs, bupropion is a unique option for the treatment of MDD as it lacks any clinically relevant serotonergic effects, typical of other mood medications, or any effects on histamine or adrenaline receptors. Lack of activity at these receptors results in a more tolerable side effect profile; bupropion is less likely to cause sexual side effects, sedation, or weight gain as compared to SSRIs or TCAs, for example. When used as an aid to smoking cessation, bupropion is thought to confer its anti-craving and anti-withdrawal effects by inhibiting dopamine reuptake, which is thought to be involved in the reward pathways associated with nicotine, and through the antagonism of the nicotinic acetylcholinergic receptor (AChR), thereby blunting the effects of nicotine. Furthermore, the stimulatory effects produced by bupropion in the central nervous system are similar to nicotine's effects, making low doses of bupropion a suitable option as a nicotine substitute. When used in combination with naltrexone in the marketed product ContraveⓇ for chronic weight management, the two components are thought to have effects on areas of the brain involved in the regulation of food intake. This includes the hypothalamus, which is involved in appetite regulation, and the mesolimbic dopamine circuit, which is involved in reward pathways. Studies have shown that the combined activity of bupropion and naltrexone increase the firing rate of hypothalamic pro-opiomelanocortin (POMC) neurons and blockade of opioid receptor-mediated POMC auto-inhibition, which are associated with a reduction in food intake and increased energy expenditure. This combination was also found to reduce food intake when injected directly into the ventral tegmental area of the mesolimbic circuit in mice, which is an area associated with the regulation of reward pathways. •Mechanism of action (Drug B): Norepinephrine functions as a peripheral vasoconstrictor by acting on alpha-adrenergic receptors. It is also an inotropic stimulator of the heart and dilator of coronary arteries as a result of it's activity at the beta-adrenergic receptors. •Absorption (Drug A): Bupropion is currently available in 3 distinct, but bioequivalent formulations: immediate release (IR), sustained-release (SR), and extended-release (XL). Immediate Release Formulation In humans, following oral administration of bupropion hydrochloride tablets, peak plasma bupropion concentrations are usually achieved within 2 hours. IR formulations provide a short duration of action and are therefore generally dosed three times per day. Sustained Release Formulation In humans, following oral administration of bupropion hydrochloride sustained-release tablets (SR), peak plasma concentration (Cmax) of bupropion is usually achieved within 3 hours. SR formulations provide a 12-hour extended release of medication and are therefore generally dosed twice per day. Extended Release Formulation Following single oral administration of bupropion hydrochloride extended-release tablets (XL) to healthy volunteers, the median time to peak plasma concentrations for bupropion was approximately 5 hours. The presence of food did not affect the peak concentration or area under the curve of bupropion. XL formulations provide a 24-hour extended release of medication and are therefore generally dosed once per day/ In a trial comparing chronic dosing with bupropion hydrochloride extended-release tablets (SR) 150 mg twice daily to bupropion immediate-release formulation 100 mg 3 times daily, the steady state Cmax for bupropion after bupropion hydrochloride sustained-release tablets (SR) administration was approximately 85% of those achieved after bupropion immediate-release formulation administration. Exposure (AUC) to bupropion was equivalent for both formulations. Bioequivalence was also demonstrated for all three major active metabolites (i.e., hydroxybupropion, threohydrobupropion and erythrohydrobupropion) for both Cmax and AUC. Thus, at steady state, bupropion hydrochloride sustained-release tablets (SR) given twice daily, and the immediate-release formulation of bupropion given 3 times daily, are essentially bioequivalent for both bupropion and the 3 quantitatively important metabolites. Furthermore, in a study comparing 14-day dosing with bupropion hydrochloride extended-release tablets (XL), 300 mg once-daily to the immediate-release formulation of bupropion at 100 mg 3 times daily, equivalence was demonstrated for peak plasma concentration and area under the curve for bupropion and the three metabolites (hydroxybupropion, threohydrobupropion, and erythrohydrobupropion). Additionally, in a study comparing 14-day dosing with bupropion hydrochloride extended-release tablets (XL) 300 mg once daily to the sustained-release formulation of bupropion at 150 mg 2 times daily, equivalence was demonstrated for peak plasma concentration and area under the curve for bupropion and the three metabolites. Bupropion hydrochloride extended-release tablets (SR) can be taken with or without food. Bupropion Cmax and AUC were increased by 11% to 35% and 16% to 19%, respectively, when bupropion hydrochloride extended-release tablets (SR) was administered with food to healthy volunteers in three trials. The food effect is not considered clinically significant. Following a single-dose administration of bupropion hydrochloride extended-release tablets (SR) in humans, Cmax of bupropion's metabolite hydroxybupropion occurs approximately 6 hours post-dose and is approximately 10 times the peak level of the parent drug at steady state. The elimination half-life of hydroxybupropion is approximately 20 (±5) hours and its AUC at steady state is about 17 times that of bupropion. The times to peak concentrations for the erythrohydrobupropion and threohydrobupropion metabolites are similar to that of the hydroxybupropion metabolite. However, their elimination half-lives are longer, 33(±10) and 37 (±13) hours, respectively, and steady-state AUCs are 1.5 and 7 times that of bupropion, respectively. •Absorption (Drug B): No absorption available •Volume of distribution (Drug A): No volume of distribution available •Volume of distribution (Drug B): No volume of distribution available •Protein binding (Drug A): In vitro tests show that bupropion is 84% bound to human plasma proteins at concentrations up to 200 mcg per mL. The extent of protein binding of the hydroxybupropion metabolite is similar to that for bupropion, whereas the extent of protein binding of the threohydrobupropion metabolite is about half that seen with bupropion. •Protein binding (Drug B): No protein binding available •Metabolism (Drug A): Bupropion is extensively metabolized in humans. Three metabolites are active: hydroxybupropion, which is formed via hydroxylation of the tert-butyl group of bupropion, and the amino-alcohol isomers, threohydrobupropion and erythrohydrobupropion, which are formed via reduction of the carbonyl group. In vitro findings suggest that CYP2B6 is the principal isoenzyme involved in the formation of hydroxybupropion, while cytochrome P450 enzymes are not involved in the formation of threohydrobupropion. Hydroxybupropion has been shown to have the same affinity as bupropion for the norepinephrine transporter (NET) but approximately 50% of its antidepressant activity despite reaching concentrations of ~10-fold higher than that of the parent drug. Oxidation of the bupropion side chain results in the formation of a glycine conjugate of meta-chlorobenzoic acid, which is then excreted as the major urinary metabolite. The potency and toxicity of the metabolites relative to bupropion have not been fully characterized. However, it has been demonstrated in an antidepressant screening test in mice that hydroxybupropion is one-half as potent as bupropion, while threohydrobupropion and erythrohydrobupropion are 5-fold less potent than bupropion. This may be of clinical importance because the plasma concentrations of the metabolites are as high as or higher than those of bupropion. Bupropion and its metabolites exhibit linear kinetics following chronic administration of 300 to 450 mg per day. •Metabolism (Drug B): No metabolism available •Route of elimination (Drug A): Bupropion is extensively metabolized in humans. Oxidation of the bupropion side chain results in the formation of a glycine conjugate of metachlorobenzoic acid, which is then excreted as the major urinary metabolite. Following oral administration of 200 mg of 14C-bupropion in humans, 87% and 10% of the radioactive dose were recovered in the urine and feces, respectively. However, the fraction of the oral dose of bupropion excreted unchanged was only 0.5%, a finding consistent with the extensive metabolism of bupropion. •Route of elimination (Drug B): No route of elimination available •Half-life (Drug A): 24 hours •Half-life (Drug B): No half-life available •Clearance (Drug A): No clearance available •Clearance (Drug B): No clearance available •Toxicity (Drug A): Symptoms of overdose include seizures, hallucinations, loss of consciousness, tachycardia, and cardiac arrest. •Toxicity (Drug B): In high dose and especially when it is combined with other vasopressors, it can lead to limb ischemia and limb death. •Brand Names (Drug A): Aplenzin, Auvelity, Budeprion, Contrave, Forfivo, Wellbutrin, Zyban •Brand Names (Drug B): Levophed •Synonyms (Drug A): No synonyms listed •Synonyms (Drug B): (R)-noradrenaline (R)-norepinephrine Arterenol L-noradrenaline L-Norepinephrine Nor-adrenaline Noradrenaline Norepinefrina Norepinephrine Norépinéphrine Norepinephrinum •Summary (Drug A): Bupropion is a norepinephrine and dopamine reuptake inhibitor used in the treatment of major depressive disorder (MDD), seasonal affective disorder (SAD), and as an aid to smoking cessation. •Summary (Drug B): Norepinephrine is a sympathomimetic used in the control of blood pressure during various hypotensive states and as an adjunct treatment during cardiac arrest. Output: Findings from in vitro studies showed that bupropion and its metabolites inhibit OCT2, suggesting that clinically relevant interaction through inhibition of OCT2 could occur at therapeutic bupropion doses. Co-administration of bupropion with OCT2 substrates may result in attenuated OCT2-mediated efflux of those drugs, thereby increasing drug serum concentrations. The severity of the interaction is moderate.

Does Bupropion and Nortriptyline interact?

•Drug A: Bupropion •Drug B: Nortriptyline •Severity: MODERATE •Description: The risk or severity of seizure can be increased when Bupropion is combined with Nortriptyline. •Extended Description: Bupropion carries a dose-dependent risk of seizure1 that may be further exacerbated when combined with other medications that can reduce the seizure threshold (i.e. increase the risk of seizure), such as the affected drug. This risk may be also compounded by patient-specific factors that may increase the risk of seizure such as metabolic disorders and illicit drug use. •Indication (Drug A): Bupropion is indicated for the treatment of major depressive disorder (MDD), seasonal affective disorder (SAD), and as an aid to smoking cessation. When used in combination with naltrexone as the marketed product ContraveⓇ, bupropion is indicated as an adjunct to a reduced-calorie diet and increased physical activity for chronic weight management in adults with an initial body mass index (BMI) of: 30 kg/m^2 or greater (obese) or 27 kg/m^2 or greater (overweight) in the presence of at least one weight-related comorbid condition (e.g., hypertension, type 2 diabetes mellitus, or dyslipidemia). Bupropion is also used off-label as a first-line treatment in patients with ADHD and comorbid bipolar disorder when used as an adjunct to mood stabilizers. •Indication (Drug B): Nortriptyline is indicated for the relief of the symptoms of major depressive disorder (MDD). Some off-label uses for this drug include treatment of chronic pain, myofascial pain, neuralgia, and irritable bowel syndrome. •Pharmacodynamics (Drug A): Bupropion is chemically unrelated to tricyclic, tetracyclic, selective serotonin re-uptake inhibitors, or other known antidepressant agents. Compared to classical tricyclic antidepressants, Bupropion is a relatively weak inhibitor of the neuronal uptake of norepinephrine and dopamine. In addition, Bupropion does not inhibit monoamine oxidase. Bupropion has been found to be essentially inactive at the serotonin transporter (SERT)(IC50 >10 000 nM), however both bupropion and its primary metabolite hydroxybupropion have been found to block the function of cation-selective serotonin type 3A receptors (5-HT3ARs). Bupropion produces dose-related central nervous system (CNS) stimulant effects in animals, as evidenced by increased locomotor activity, increased rates of responding in various schedule-controlled operant behaviour tasks, and, at high doses, induction of mild stereotyped behaviour. Due to these stimulant effects and selective activity at dopamine and norepinephrine receptors, bupropion has been identified as having an abuse potential. Bupropion has a similar structure to the controlled substance Cathinone, and has been identified as having mild amphetamine-like activity, particularly when inhaled or injected. Bupropion is also known to lower the seizure threshold, making any pre-existing seizure conditions a contraindication to its use. This risk is exacerbated when bupropion is combined with other drugs or substances that lower the seizure threshold, such as cocaine, or in clinical situations that would increase the risk of a seizure such as abrupt alcohol or benzodiazepine withdrawal. As norepinephrine has been shown to have anticonvulsant properties, bupropion's inhibitory effects on NET are thought to contribute to its pro-convulsant activity. Bupropion has been shown to increase blood pressure and pose a risk for exacerbation of unmanaged or pre-existing hypertension, however, clinical trials of bupropion in smokers with CVD have not identified an increased incidence of CV events including stroke or heart attack. In clinical trials, the mean increase in systolic blood pressure associated with the use of bupropion was found to be 1.3 mmHg. •Pharmacodynamics (Drug B): Nortriptyline exerts antidepressant effects likely by inhibiting the reuptake of serotonin and norepinephrine at neuronal cell membranes. It also exerts antimuscarinic effects through its actions on the acetylcholine receptor. •Mechanism of action (Drug A): Bupropion is a norepinephrine/dopamine-reuptake inhibitor (NDRI) that exerts its pharmacological effects by weakly inhibiting the enzymes involved in the uptake of the neurotransmitters norepinephrine and dopamine from the synaptic cleft, therefore prolonging their duration of action within the neuronal synapse and the downstream effects of these neurotransmitters. More specifically, bupropion binds to the norepinephrine transporter (NET) and the dopamine transporter (DAT). Bupropion was originally classified as an "atypical" antidepressant because it does not exert the same effects as the classical antidepressants such as Monoamine Oxidase Inhibitors (MAOIs), Tricyclic Antidepressants (TCAs), or Selective Serotonin Reuptake Inhibitors (SSRIs). While it has comparable effectiveness to typical first-line options for the treatment of depression such as SSRIs, bupropion is a unique option for the treatment of MDD as it lacks any clinically relevant serotonergic effects, typical of other mood medications, or any effects on histamine or adrenaline receptors. Lack of activity at these receptors results in a more tolerable side effect profile; bupropion is less likely to cause sexual side effects, sedation, or weight gain as compared to SSRIs or TCAs, for example. When used as an aid to smoking cessation, bupropion is thought to confer its anti-craving and anti-withdrawal effects by inhibiting dopamine reuptake, which is thought to be involved in the reward pathways associated with nicotine, and through the antagonism of the nicotinic acetylcholinergic receptor (AChR), thereby blunting the effects of nicotine. Furthermore, the stimulatory effects produced by bupropion in the central nervous system are similar to nicotine's effects, making low doses of bupropion a suitable option as a nicotine substitute. When used in combination with naltrexone in the marketed product ContraveⓇ for chronic weight management, the two components are thought to have effects on areas of the brain involved in the regulation of food intake. This includes the hypothalamus, which is involved in appetite regulation, and the mesolimbic dopamine circuit, which is involved in reward pathways. Studies have shown that the combined activity of bupropion and naltrexone increase the firing rate of hypothalamic pro-opiomelanocortin (POMC) neurons and blockade of opioid receptor-mediated POMC auto-inhibition, which are associated with a reduction in food intake and increased energy expenditure. This combination was also found to reduce food intake when injected directly into the ventral tegmental area of the mesolimbic circuit in mice, which is an area associated with the regulation of reward pathways. •Mechanism of action (Drug B): Though prescribing information does not identify a specific mechanism of action for nortriptyline, is believed that nortriptyline either inhibits the reuptake of the neurotransmitter serotonin at the neuronal membrane or acts at the level of the beta-adrenergic receptors. It displays a more selective reuptake inhibition for noradrenaline, which may explain increased symptom improvement after nortriptyline therapy. Tricyclic antidepressants do not inhibit monoamine oxidase nor do they affect dopamine reuptake. As with other tricyclics, nortriptyline displays affinity for other receptors including mACh receptors, histamine receptors, 5-HT receptors, in addition to other receptors. •Absorption (Drug A): Bupropion is currently available in 3 distinct, but bioequivalent formulations: immediate release (IR), sustained-release (SR), and extended-release (XL). Immediate Release Formulation In humans, following oral administration of bupropion hydrochloride tablets, peak plasma bupropion concentrations are usually achieved within 2 hours. IR formulations provide a short duration of action and are therefore generally dosed three times per day. Sustained Release Formulation In humans, following oral administration of bupropion hydrochloride sustained-release tablets (SR), peak plasma concentration (Cmax) of bupropion is usually achieved within 3 hours. SR formulations provide a 12-hour extended release of medication and are therefore generally dosed twice per day. Extended Release Formulation Following single oral administration of bupropion hydrochloride extended-release tablets (XL) to healthy volunteers, the median time to peak plasma concentrations for bupropion was approximately 5 hours. The presence of food did not affect the peak concentration or area under the curve of bupropion. XL formulations provide a 24-hour extended release of medication and are therefore generally dosed once per day/ In a trial comparing chronic dosing with bupropion hydrochloride extended-release tablets (SR) 150 mg twice daily to bupropion immediate-release formulation 100 mg 3 times daily, the steady state Cmax for bupropion after bupropion hydrochloride sustained-release tablets (SR) administration was approximately 85% of those achieved after bupropion immediate-release formulation administration. Exposure (AUC) to bupropion was equivalent for both formulations. Bioequivalence was also demonstrated for all three major active metabolites (i.e., hydroxybupropion, threohydrobupropion and erythrohydrobupropion) for both Cmax and AUC. Thus, at steady state, bupropion hydrochloride sustained-release tablets (SR) given twice daily, and the immediate-release formulation of bupropion given 3 times daily, are essentially bioequivalent for both bupropion and the 3 quantitatively important metabolites. Furthermore, in a study comparing 14-day dosing with bupropion hydrochloride extended-release tablets (XL), 300 mg once-daily to the immediate-release formulation of bupropion at 100 mg 3 times daily, equivalence was demonstrated for peak plasma concentration and area under the curve for bupropion and the three metabolites (hydroxybupropion, threohydrobupropion, and erythrohydrobupropion). Additionally, in a study comparing 14-day dosing with bupropion hydrochloride extended-release tablets (XL) 300 mg once daily to the sustained-release formulation of bupropion at 150 mg 2 times daily, equivalence was demonstrated for peak plasma concentration and area under the curve for bupropion and the three metabolites. Bupropion hydrochloride extended-release tablets (SR) can be taken with or without food. Bupropion Cmax and AUC were increased by 11% to 35% and 16% to 19%, respectively, when bupropion hydrochloride extended-release tablets (SR) was administered with food to healthy volunteers in three trials. The food effect is not considered clinically significant. Following a single-dose administration of bupropion hydrochloride extended-release tablets (SR) in humans, Cmax of bupropion's metabolite hydroxybupropion occurs approximately 6 hours post-dose and is approximately 10 times the peak level of the parent drug at steady state. The elimination half-life of hydroxybupropion is approximately 20 (±5) hours and its AUC at steady state is about 17 times that of bupropion. The times to peak concentrations for the erythrohydrobupropion and threohydrobupropion metabolites are similar to that of the hydroxybupropion metabolite. However, their elimination half-lives are longer, 33(±10) and 37 (±13) hours, respectively, and steady-state AUCs are 1.5 and 7 times that of bupropion, respectively. •Absorption (Drug B): Nortriptyline is readily absorbed in the gastrointestinal tract with extensive variation in plasma levels, depending on the patient. This drug undergoes first-pass metabolism and its plasma concentrations are attained within 7 to 8.5 hours after oral administration. The bioavailability of nortriptyline varies considerably and ranges from 45 to 85%. •Volume of distribution (Drug A): No volume of distribution available •Volume of distribution (Drug B): The apparent volume of distribution (Vd)β, estimated after intravenous administration is 1633 ± 268 L within the range of 1460 to 2030 (21 ± 4 L/kg). Nortriptyline crosses the placenta and is found in the breast milk. It distributes to the heart, lungs, brain, and the liver. •Protein binding (Drug A): In vitro tests show that bupropion is 84% bound to human plasma proteins at concentrations up to 200 mcg per mL. The extent of protein binding of the hydroxybupropion metabolite is similar to that for bupropion, whereas the extent of protein binding of the threohydrobupropion metabolite is about half that seen with bupropion. •Protein binding (Drug B): The plasma protein binding of nortriptyline is approximately 93%. •Metabolism (Drug A): Bupropion is extensively metabolized in humans. Three metabolites are active: hydroxybupropion, which is formed via hydroxylation of the tert-butyl group of bupropion, and the amino-alcohol isomers, threohydrobupropion and erythrohydrobupropion, which are formed via reduction of the carbonyl group. In vitro findings suggest that CYP2B6 is the principal isoenzyme involved in the formation of hydroxybupropion, while cytochrome P450 enzymes are not involved in the formation of threohydrobupropion. Hydroxybupropion has been shown to have the same affinity as bupropion for the norepinephrine transporter (NET) but approximately 50% of its antidepressant activity despite reaching concentrations of ~10-fold higher than that of the parent drug. Oxidation of the bupropion side chain results in the formation of a glycine conjugate of meta-chlorobenzoic acid, which is then excreted as the major urinary metabolite. The potency and toxicity of the metabolites relative to bupropion have not been fully characterized. However, it has been demonstrated in an antidepressant screening test in mice that hydroxybupropion is one-half as potent as bupropion, while threohydrobupropion and erythrohydrobupropion are 5-fold less potent than bupropion. This may be of clinical importance because the plasma concentrations of the metabolites are as high as or higher than those of bupropion. Bupropion and its metabolites exhibit linear kinetics following chronic administration of 300 to 450 mg per day. •Metabolism (Drug B): Nortriptyline is metabolized via demethylation and hydroxylation in the liver followed by glucuronic acid conjugation. CYP2D6 plays a large role in nortriptyline metabolism, with contributions from CYP1A2, CYP2C19 and CYP3A4. The main active metabolite is 10-hydroxynortriptyline exists in both cis and a trans form, with the trans form is higher in potency. 10-hydroxynortriptyline is the most frequently found in the plasma. Most of the other metabolites are conjugated, and are less potent. •Route of elimination (Drug A): Bupropion is extensively metabolized in humans. Oxidation of the bupropion side chain results in the formation of a glycine conjugate of metachlorobenzoic acid, which is then excreted as the major urinary metabolite. Following oral administration of 200 mg of 14C-bupropion in humans, 87% and 10% of the radioactive dose were recovered in the urine and feces, respectively. However, the fraction of the oral dose of bupropion excreted unchanged was only 0.5%, a finding consistent with the extensive metabolism of bupropion. •Route of elimination (Drug B): Nortriptyline and its metabolites are mainly excreted in the urine, where only small amounts (2%) of the total drug is recovered as unchanged parent compound. Approximately one-third of a single orally administered dose is excreted in urine within 24 hours. Small amounts are excreted in feces via biliary elimination. •Half-life (Drug A): 24 hours •Half-life (Drug B): The average plasma half-life of nortriptyline in healthy volunteers is about 26 hours, but is said to range from 16 to 38 hours. One study mentions a mean half-life of about 39 hours. •Clearance (Drug A): No clearance available •Clearance (Drug B): The average plasma clearance of nortriptyline in a study of healthy volunteers was 54 L/h. The average systemic clearance of nortriptyline is 30.6 ± 6.9 L / h, within the range of 18.6 to 39.6 L/hour. •Toxicity (Drug A): Symptoms of overdose include seizures, hallucinations, loss of consciousness, tachycardia, and cardiac arrest. •Toxicity (Drug B): The oral LD50 of nortriptyline in the rat is 405 mg/kg. Symptoms of overdose with nortriptyline include cardiac arrhythmias, severe hypotension, shock, congestive heart failure, pulmonary edema, convulsions, coma, and CNS depression. Changes in the electrocardiogram, particularly in QRS segment, may be indicative of tricyclic antidepressant toxicity. •Brand Names (Drug A): Aplenzin, Auvelity, Budeprion, Contrave, Forfivo, Wellbutrin, Zyban •Brand Names (Drug B): Aventyl, Pamelor •Synonyms (Drug A): No synonyms listed •Synonyms (Drug B): Demethylamitriptyline Desmethylamitriptyline Nortriptylina Nortriptyline Nortriptylinum •Summary (Drug A): Bupropion is a norepinephrine and dopamine reuptake inhibitor used in the treatment of major depressive disorder (MDD), seasonal affective disorder (SAD), and as an aid to smoking cessation. •Summary (Drug B): Nortriptyline is a tricyclic antidepressant used in the treatment of depression.

Bupropion carries a dose-dependent risk of seizure1 that may be further exacerbated when combined with other medications that can reduce the seizure threshold (i.e. increase the risk of seizure), such as the affected drug. This risk may be also compounded by patient-specific factors that may increase the risk of seizure such as metabolic disorders and illicit drug use. The severity of the interaction is moderate.

Question: Does Bupropion and Nortriptyline interact? Information: •Drug A: Bupropion •Drug B: Nortriptyline •Severity: MODERATE •Description: The risk or severity of seizure can be increased when Bupropion is combined with Nortriptyline. •Extended Description: Bupropion carries a dose-dependent risk of seizure1 that may be further exacerbated when combined with other medications that can reduce the seizure threshold (i.e. increase the risk of seizure), such as the affected drug. This risk may be also compounded by patient-specific factors that may increase the risk of seizure such as metabolic disorders and illicit drug use. •Indication (Drug A): Bupropion is indicated for the treatment of major depressive disorder (MDD), seasonal affective disorder (SAD), and as an aid to smoking cessation. When used in combination with naltrexone as the marketed product ContraveⓇ, bupropion is indicated as an adjunct to a reduced-calorie diet and increased physical activity for chronic weight management in adults with an initial body mass index (BMI) of: 30 kg/m^2 or greater (obese) or 27 kg/m^2 or greater (overweight) in the presence of at least one weight-related comorbid condition (e.g., hypertension, type 2 diabetes mellitus, or dyslipidemia). Bupropion is also used off-label as a first-line treatment in patients with ADHD and comorbid bipolar disorder when used as an adjunct to mood stabilizers. •Indication (Drug B): Nortriptyline is indicated for the relief of the symptoms of major depressive disorder (MDD). Some off-label uses for this drug include treatment of chronic pain, myofascial pain, neuralgia, and irritable bowel syndrome. •Pharmacodynamics (Drug A): Bupropion is chemically unrelated to tricyclic, tetracyclic, selective serotonin re-uptake inhibitors, or other known antidepressant agents. Compared to classical tricyclic antidepressants, Bupropion is a relatively weak inhibitor of the neuronal uptake of norepinephrine and dopamine. In addition, Bupropion does not inhibit monoamine oxidase. Bupropion has been found to be essentially inactive at the serotonin transporter (SERT)(IC50 >10 000 nM), however both bupropion and its primary metabolite hydroxybupropion have been found to block the function of cation-selective serotonin type 3A receptors (5-HT3ARs). Bupropion produces dose-related central nervous system (CNS) stimulant effects in animals, as evidenced by increased locomotor activity, increased rates of responding in various schedule-controlled operant behaviour tasks, and, at high doses, induction of mild stereotyped behaviour. Due to these stimulant effects and selective activity at dopamine and norepinephrine receptors, bupropion has been identified as having an abuse potential. Bupropion has a similar structure to the controlled substance Cathinone, and has been identified as having mild amphetamine-like activity, particularly when inhaled or injected. Bupropion is also known to lower the seizure threshold, making any pre-existing seizure conditions a contraindication to its use. This risk is exacerbated when bupropion is combined with other drugs or substances that lower the seizure threshold, such as cocaine, or in clinical situations that would increase the risk of a seizure such as abrupt alcohol or benzodiazepine withdrawal. As norepinephrine has been shown to have anticonvulsant properties, bupropion's inhibitory effects on NET are thought to contribute to its pro-convulsant activity. Bupropion has been shown to increase blood pressure and pose a risk for exacerbation of unmanaged or pre-existing hypertension, however, clinical trials of bupropion in smokers with CVD have not identified an increased incidence of CV events including stroke or heart attack. In clinical trials, the mean increase in systolic blood pressure associated with the use of bupropion was found to be 1.3 mmHg. •Pharmacodynamics (Drug B): Nortriptyline exerts antidepressant effects likely by inhibiting the reuptake of serotonin and norepinephrine at neuronal cell membranes. It also exerts antimuscarinic effects through its actions on the acetylcholine receptor. •Mechanism of action (Drug A): Bupropion is a norepinephrine/dopamine-reuptake inhibitor (NDRI) that exerts its pharmacological effects by weakly inhibiting the enzymes involved in the uptake of the neurotransmitters norepinephrine and dopamine from the synaptic cleft, therefore prolonging their duration of action within the neuronal synapse and the downstream effects of these neurotransmitters. More specifically, bupropion binds to the norepinephrine transporter (NET) and the dopamine transporter (DAT). Bupropion was originally classified as an "atypical" antidepressant because it does not exert the same effects as the classical antidepressants such as Monoamine Oxidase Inhibitors (MAOIs), Tricyclic Antidepressants (TCAs), or Selective Serotonin Reuptake Inhibitors (SSRIs). While it has comparable effectiveness to typical first-line options for the treatment of depression such as SSRIs, bupropion is a unique option for the treatment of MDD as it lacks any clinically relevant serotonergic effects, typical of other mood medications, or any effects on histamine or adrenaline receptors. Lack of activity at these receptors results in a more tolerable side effect profile; bupropion is less likely to cause sexual side effects, sedation, or weight gain as compared to SSRIs or TCAs, for example. When used as an aid to smoking cessation, bupropion is thought to confer its anti-craving and anti-withdrawal effects by inhibiting dopamine reuptake, which is thought to be involved in the reward pathways associated with nicotine, and through the antagonism of the nicotinic acetylcholinergic receptor (AChR), thereby blunting the effects of nicotine. Furthermore, the stimulatory effects produced by bupropion in the central nervous system are similar to nicotine's effects, making low doses of bupropion a suitable option as a nicotine substitute. When used in combination with naltrexone in the marketed product ContraveⓇ for chronic weight management, the two components are thought to have effects on areas of the brain involved in the regulation of food intake. This includes the hypothalamus, which is involved in appetite regulation, and the mesolimbic dopamine circuit, which is involved in reward pathways. Studies have shown that the combined activity of bupropion and naltrexone increase the firing rate of hypothalamic pro-opiomelanocortin (POMC) neurons and blockade of opioid receptor-mediated POMC auto-inhibition, which are associated with a reduction in food intake and increased energy expenditure. This combination was also found to reduce food intake when injected directly into the ventral tegmental area of the mesolimbic circuit in mice, which is an area associated with the regulation of reward pathways. •Mechanism of action (Drug B): Though prescribing information does not identify a specific mechanism of action for nortriptyline, is believed that nortriptyline either inhibits the reuptake of the neurotransmitter serotonin at the neuronal membrane or acts at the level of the beta-adrenergic receptors. It displays a more selective reuptake inhibition for noradrenaline, which may explain increased symptom improvement after nortriptyline therapy. Tricyclic antidepressants do not inhibit monoamine oxidase nor do they affect dopamine reuptake. As with other tricyclics, nortriptyline displays affinity for other receptors including mACh receptors, histamine receptors, 5-HT receptors, in addition to other receptors. •Absorption (Drug A): Bupropion is currently available in 3 distinct, but bioequivalent formulations: immediate release (IR), sustained-release (SR), and extended-release (XL). Immediate Release Formulation In humans, following oral administration of bupropion hydrochloride tablets, peak plasma bupropion concentrations are usually achieved within 2 hours. IR formulations provide a short duration of action and are therefore generally dosed three times per day. Sustained Release Formulation In humans, following oral administration of bupropion hydrochloride sustained-release tablets (SR), peak plasma concentration (Cmax) of bupropion is usually achieved within 3 hours. SR formulations provide a 12-hour extended release of medication and are therefore generally dosed twice per day. Extended Release Formulation Following single oral administration of bupropion hydrochloride extended-release tablets (XL) to healthy volunteers, the median time to peak plasma concentrations for bupropion was approximately 5 hours. The presence of food did not affect the peak concentration or area under the curve of bupropion. XL formulations provide a 24-hour extended release of medication and are therefore generally dosed once per day/ In a trial comparing chronic dosing with bupropion hydrochloride extended-release tablets (SR) 150 mg twice daily to bupropion immediate-release formulation 100 mg 3 times daily, the steady state Cmax for bupropion after bupropion hydrochloride sustained-release tablets (SR) administration was approximately 85% of those achieved after bupropion immediate-release formulation administration. Exposure (AUC) to bupropion was equivalent for both formulations. Bioequivalence was also demonstrated for all three major active metabolites (i.e., hydroxybupropion, threohydrobupropion and erythrohydrobupropion) for both Cmax and AUC. Thus, at steady state, bupropion hydrochloride sustained-release tablets (SR) given twice daily, and the immediate-release formulation of bupropion given 3 times daily, are essentially bioequivalent for both bupropion and the 3 quantitatively important metabolites. Furthermore, in a study comparing 14-day dosing with bupropion hydrochloride extended-release tablets (XL), 300 mg once-daily to the immediate-release formulation of bupropion at 100 mg 3 times daily, equivalence was demonstrated for peak plasma concentration and area under the curve for bupropion and the three metabolites (hydroxybupropion, threohydrobupropion, and erythrohydrobupropion). Additionally, in a study comparing 14-day dosing with bupropion hydrochloride extended-release tablets (XL) 300 mg once daily to the sustained-release formulation of bupropion at 150 mg 2 times daily, equivalence was demonstrated for peak plasma concentration and area under the curve for bupropion and the three metabolites. Bupropion hydrochloride extended-release tablets (SR) can be taken with or without food. Bupropion Cmax and AUC were increased by 11% to 35% and 16% to 19%, respectively, when bupropion hydrochloride extended-release tablets (SR) was administered with food to healthy volunteers in three trials. The food effect is not considered clinically significant. Following a single-dose administration of bupropion hydrochloride extended-release tablets (SR) in humans, Cmax of bupropion's metabolite hydroxybupropion occurs approximately 6 hours post-dose and is approximately 10 times the peak level of the parent drug at steady state. The elimination half-life of hydroxybupropion is approximately 20 (±5) hours and its AUC at steady state is about 17 times that of bupropion. The times to peak concentrations for the erythrohydrobupropion and threohydrobupropion metabolites are similar to that of the hydroxybupropion metabolite. However, their elimination half-lives are longer, 33(±10) and 37 (±13) hours, respectively, and steady-state AUCs are 1.5 and 7 times that of bupropion, respectively. •Absorption (Drug B): Nortriptyline is readily absorbed in the gastrointestinal tract with extensive variation in plasma levels, depending on the patient. This drug undergoes first-pass metabolism and its plasma concentrations are attained within 7 to 8.5 hours after oral administration. The bioavailability of nortriptyline varies considerably and ranges from 45 to 85%. •Volume of distribution (Drug A): No volume of distribution available •Volume of distribution (Drug B): The apparent volume of distribution (Vd)β, estimated after intravenous administration is 1633 ± 268 L within the range of 1460 to 2030 (21 ± 4 L/kg). Nortriptyline crosses the placenta and is found in the breast milk. It distributes to the heart, lungs, brain, and the liver. •Protein binding (Drug A): In vitro tests show that bupropion is 84% bound to human plasma proteins at concentrations up to 200 mcg per mL. The extent of protein binding of the hydroxybupropion metabolite is similar to that for bupropion, whereas the extent of protein binding of the threohydrobupropion metabolite is about half that seen with bupropion. •Protein binding (Drug B): The plasma protein binding of nortriptyline is approximately 93%. •Metabolism (Drug A): Bupropion is extensively metabolized in humans. Three metabolites are active: hydroxybupropion, which is formed via hydroxylation of the tert-butyl group of bupropion, and the amino-alcohol isomers, threohydrobupropion and erythrohydrobupropion, which are formed via reduction of the carbonyl group. In vitro findings suggest that CYP2B6 is the principal isoenzyme involved in the formation of hydroxybupropion, while cytochrome P450 enzymes are not involved in the formation of threohydrobupropion. Hydroxybupropion has been shown to have the same affinity as bupropion for the norepinephrine transporter (NET) but approximately 50% of its antidepressant activity despite reaching concentrations of ~10-fold higher than that of the parent drug. Oxidation of the bupropion side chain results in the formation of a glycine conjugate of meta-chlorobenzoic acid, which is then excreted as the major urinary metabolite. The potency and toxicity of the metabolites relative to bupropion have not been fully characterized. However, it has been demonstrated in an antidepressant screening test in mice that hydroxybupropion is one-half as potent as bupropion, while threohydrobupropion and erythrohydrobupropion are 5-fold less potent than bupropion. This may be of clinical importance because the plasma concentrations of the metabolites are as high as or higher than those of bupropion. Bupropion and its metabolites exhibit linear kinetics following chronic administration of 300 to 450 mg per day. •Metabolism (Drug B): Nortriptyline is metabolized via demethylation and hydroxylation in the liver followed by glucuronic acid conjugation. CYP2D6 plays a large role in nortriptyline metabolism, with contributions from CYP1A2, CYP2C19 and CYP3A4. The main active metabolite is 10-hydroxynortriptyline exists in both cis and a trans form, with the trans form is higher in potency. 10-hydroxynortriptyline is the most frequently found in the plasma. Most of the other metabolites are conjugated, and are less potent. •Route of elimination (Drug A): Bupropion is extensively metabolized in humans. Oxidation of the bupropion side chain results in the formation of a glycine conjugate of metachlorobenzoic acid, which is then excreted as the major urinary metabolite. Following oral administration of 200 mg of 14C-bupropion in humans, 87% and 10% of the radioactive dose were recovered in the urine and feces, respectively. However, the fraction of the oral dose of bupropion excreted unchanged was only 0.5%, a finding consistent with the extensive metabolism of bupropion. •Route of elimination (Drug B): Nortriptyline and its metabolites are mainly excreted in the urine, where only small amounts (2%) of the total drug is recovered as unchanged parent compound. Approximately one-third of a single orally administered dose is excreted in urine within 24 hours. Small amounts are excreted in feces via biliary elimination. •Half-life (Drug A): 24 hours •Half-life (Drug B): The average plasma half-life of nortriptyline in healthy volunteers is about 26 hours, but is said to range from 16 to 38 hours. One study mentions a mean half-life of about 39 hours. •Clearance (Drug A): No clearance available •Clearance (Drug B): The average plasma clearance of nortriptyline in a study of healthy volunteers was 54 L/h. The average systemic clearance of nortriptyline is 30.6 ± 6.9 L / h, within the range of 18.6 to 39.6 L/hour. •Toxicity (Drug A): Symptoms of overdose include seizures, hallucinations, loss of consciousness, tachycardia, and cardiac arrest. •Toxicity (Drug B): The oral LD50 of nortriptyline in the rat is 405 mg/kg. Symptoms of overdose with nortriptyline include cardiac arrhythmias, severe hypotension, shock, congestive heart failure, pulmonary edema, convulsions, coma, and CNS depression. Changes in the electrocardiogram, particularly in QRS segment, may be indicative of tricyclic antidepressant toxicity. •Brand Names (Drug A): Aplenzin, Auvelity, Budeprion, Contrave, Forfivo, Wellbutrin, Zyban •Brand Names (Drug B): Aventyl, Pamelor •Synonyms (Drug A): No synonyms listed •Synonyms (Drug B): Demethylamitriptyline Desmethylamitriptyline Nortriptylina Nortriptyline Nortriptylinum •Summary (Drug A): Bupropion is a norepinephrine and dopamine reuptake inhibitor used in the treatment of major depressive disorder (MDD), seasonal affective disorder (SAD), and as an aid to smoking cessation. •Summary (Drug B): Nortriptyline is a tricyclic antidepressant used in the treatment of depression. Output: Bupropion carries a dose-dependent risk of seizure1 that may be further exacerbated when combined with other medications that can reduce the seizure threshold (i.e. increase the risk of seizure), such as the affected drug. This risk may be also compounded by patient-specific factors that may increase the risk of seizure such as metabolic disorders and illicit drug use. The severity of the interaction is moderate.

Does Bupropion and Noscapine interact?

•Drug A: Bupropion •Drug B: Noscapine •Severity: MODERATE •Description: The metabolism of Bupropion can be decreased when combined with Noscapine. •Extended Description: The subject drug is known to be an inhibitor of CYP2C9 while the affected drug is reported to be metabolized by CYP2C9. Concomitant administration of these agents can cause an increase in the serum concentration of the affected drug due to decreased metabolism by CYP2C9, which may result in increased incidence and/or severity of adverse effects related to the affected drug. •Indication (Drug A): Bupropion is indicated for the treatment of major depressive disorder (MDD), seasonal affective disorder (SAD), and as an aid to smoking cessation. When used in combination with naltrexone as the marketed product ContraveⓇ, bupropion is indicated as an adjunct to a reduced-calorie diet and increased physical activity for chronic weight management in adults with an initial body mass index (BMI) of: 30 kg/m^2 or greater (obese) or 27 kg/m^2 or greater (overweight) in the presence of at least one weight-related comorbid condition (e.g., hypertension, type 2 diabetes mellitus, or dyslipidemia). Bupropion is also used off-label as a first-line treatment in patients with ADHD and comorbid bipolar disorder when used as an adjunct to mood stabilizers. •Indication (Drug B): Investigated for use/treatment in lymphoma (non-hodgkin's), leukemia (lymphoid), cancer/tumors (unspecified), and multiple myeloma. •Pharmacodynamics (Drug A): Bupropion is chemically unrelated to tricyclic, tetracyclic, selective serotonin re-uptake inhibitors, or other known antidepressant agents. Compared to classical tricyclic antidepressants, Bupropion is a relatively weak inhibitor of the neuronal uptake of norepinephrine and dopamine. In addition, Bupropion does not inhibit monoamine oxidase. Bupropion has been found to be essentially inactive at the serotonin transporter (SERT)(IC50 >10 000 nM), however both bupropion and its primary metabolite hydroxybupropion have been found to block the function of cation-selective serotonin type 3A receptors (5-HT3ARs). Bupropion produces dose-related central nervous system (CNS) stimulant effects in animals, as evidenced by increased locomotor activity, increased rates of responding in various schedule-controlled operant behaviour tasks, and, at high doses, induction of mild stereotyped behaviour. Due to these stimulant effects and selective activity at dopamine and norepinephrine receptors, bupropion has been identified as having an abuse potential. Bupropion has a similar structure to the controlled substance Cathinone, and has been identified as having mild amphetamine-like activity, particularly when inhaled or injected. Bupropion is also known to lower the seizure threshold, making any pre-existing seizure conditions a contraindication to its use. This risk is exacerbated when bupropion is combined with other drugs or substances that lower the seizure threshold, such as cocaine, or in clinical situations that would increase the risk of a seizure such as abrupt alcohol or benzodiazepine withdrawal. As norepinephrine has been shown to have anticonvulsant properties, bupropion's inhibitory effects on NET are thought to contribute to its pro-convulsant activity. Bupropion has been shown to increase blood pressure and pose a risk for exacerbation of unmanaged or pre-existing hypertension, however, clinical trials of bupropion in smokers with CVD have not identified an increased incidence of CV events including stroke or heart attack. In clinical trials, the mean increase in systolic blood pressure associated with the use of bupropion was found to be 1.3 mmHg. •Pharmacodynamics (Drug B): No pharmacodynamics available •Mechanism of action (Drug A): Bupropion is a norepinephrine/dopamine-reuptake inhibitor (NDRI) that exerts its pharmacological effects by weakly inhibiting the enzymes involved in the uptake of the neurotransmitters norepinephrine and dopamine from the synaptic cleft, therefore prolonging their duration of action within the neuronal synapse and the downstream effects of these neurotransmitters. More specifically, bupropion binds to the norepinephrine transporter (NET) and the dopamine transporter (DAT). Bupropion was originally classified as an "atypical" antidepressant because it does not exert the same effects as the classical antidepressants such as Monoamine Oxidase Inhibitors (MAOIs), Tricyclic Antidepressants (TCAs), or Selective Serotonin Reuptake Inhibitors (SSRIs). While it has comparable effectiveness to typical first-line options for the treatment of depression such as SSRIs, bupropion is a unique option for the treatment of MDD as it lacks any clinically relevant serotonergic effects, typical of other mood medications, or any effects on histamine or adrenaline receptors. Lack of activity at these receptors results in a more tolerable side effect profile; bupropion is less likely to cause sexual side effects, sedation, or weight gain as compared to SSRIs or TCAs, for example. When used as an aid to smoking cessation, bupropion is thought to confer its anti-craving and anti-withdrawal effects by inhibiting dopamine reuptake, which is thought to be involved in the reward pathways associated with nicotine, and through the antagonism of the nicotinic acetylcholinergic receptor (AChR), thereby blunting the effects of nicotine. Furthermore, the stimulatory effects produced by bupropion in the central nervous system are similar to nicotine's effects, making low doses of bupropion a suitable option as a nicotine substitute. When used in combination with naltrexone in the marketed product ContraveⓇ for chronic weight management, the two components are thought to have effects on areas of the brain involved in the regulation of food intake. This includes the hypothalamus, which is involved in appetite regulation, and the mesolimbic dopamine circuit, which is involved in reward pathways. Studies have shown that the combined activity of bupropion and naltrexone increase the firing rate of hypothalamic pro-opiomelanocortin (POMC) neurons and blockade of opioid receptor-mediated POMC auto-inhibition, which are associated with a reduction in food intake and increased energy expenditure. This combination was also found to reduce food intake when injected directly into the ventral tegmental area of the mesolimbic circuit in mice, which is an area associated with the regulation of reward pathways. •Mechanism of action (Drug B): Noscapine's antitussive effects appear to be primarily mediated by its sigma receptor agonist activity. Evidence for this mechanism is suggested by experimental evidence in rats. Pretreatment with rimcazole, a sigma specific antagonist, causes a dose-dependent reduction in antitussive activity of noscapine. •Absorption (Drug A): Bupropion is currently available in 3 distinct, but bioequivalent formulations: immediate release (IR), sustained-release (SR), and extended-release (XL). Immediate Release Formulation In humans, following oral administration of bupropion hydrochloride tablets, peak plasma bupropion concentrations are usually achieved within 2 hours. IR formulations provide a short duration of action and are therefore generally dosed three times per day. Sustained Release Formulation In humans, following oral administration of bupropion hydrochloride sustained-release tablets (SR), peak plasma concentration (Cmax) of bupropion is usually achieved within 3 hours. SR formulations provide a 12-hour extended release of medication and are therefore generally dosed twice per day. Extended Release Formulation Following single oral administration of bupropion hydrochloride extended-release tablets (XL) to healthy volunteers, the median time to peak plasma concentrations for bupropion was approximately 5 hours. The presence of food did not affect the peak concentration or area under the curve of bupropion. XL formulations provide a 24-hour extended release of medication and are therefore generally dosed once per day/ In a trial comparing chronic dosing with bupropion hydrochloride extended-release tablets (SR) 150 mg twice daily to bupropion immediate-release formulation 100 mg 3 times daily, the steady state Cmax for bupropion after bupropion hydrochloride sustained-release tablets (SR) administration was approximately 85% of those achieved after bupropion immediate-release formulation administration. Exposure (AUC) to bupropion was equivalent for both formulations. Bioequivalence was also demonstrated for all three major active metabolites (i.e., hydroxybupropion, threohydrobupropion and erythrohydrobupropion) for both Cmax and AUC. Thus, at steady state, bupropion hydrochloride sustained-release tablets (SR) given twice daily, and the immediate-release formulation of bupropion given 3 times daily, are essentially bioequivalent for both bupropion and the 3 quantitatively important metabolites. Furthermore, in a study comparing 14-day dosing with bupropion hydrochloride extended-release tablets (XL), 300 mg once-daily to the immediate-release formulation of bupropion at 100 mg 3 times daily, equivalence was demonstrated for peak plasma concentration and area under the curve for bupropion and the three metabolites (hydroxybupropion, threohydrobupropion, and erythrohydrobupropion). Additionally, in a study comparing 14-day dosing with bupropion hydrochloride extended-release tablets (XL) 300 mg once daily to the sustained-release formulation of bupropion at 150 mg 2 times daily, equivalence was demonstrated for peak plasma concentration and area under the curve for bupropion and the three metabolites. Bupropion hydrochloride extended-release tablets (SR) can be taken with or without food. Bupropion Cmax and AUC were increased by 11% to 35% and 16% to 19%, respectively, when bupropion hydrochloride extended-release tablets (SR) was administered with food to healthy volunteers in three trials. The food effect is not considered clinically significant. Following a single-dose administration of bupropion hydrochloride extended-release tablets (SR) in humans, Cmax of bupropion's metabolite hydroxybupropion occurs approximately 6 hours post-dose and is approximately 10 times the peak level of the parent drug at steady state. The elimination half-life of hydroxybupropion is approximately 20 (±5) hours and its AUC at steady state is about 17 times that of bupropion. The times to peak concentrations for the erythrohydrobupropion and threohydrobupropion metabolites are similar to that of the hydroxybupropion metabolite. However, their elimination half-lives are longer, 33(±10) and 37 (±13) hours, respectively, and steady-state AUCs are 1.5 and 7 times that of bupropion, respectively. •Absorption (Drug B): No absorption available •Volume of distribution (Drug A): No volume of distribution available •Volume of distribution (Drug B): No volume of distribution available •Protein binding (Drug A): In vitro tests show that bupropion is 84% bound to human plasma proteins at concentrations up to 200 mcg per mL. The extent of protein binding of the hydroxybupropion metabolite is similar to that for bupropion, whereas the extent of protein binding of the threohydrobupropion metabolite is about half that seen with bupropion. •Protein binding (Drug B): No protein binding available •Metabolism (Drug A): Bupropion is extensively metabolized in humans. Three metabolites are active: hydroxybupropion, which is formed via hydroxylation of the tert-butyl group of bupropion, and the amino-alcohol isomers, threohydrobupropion and erythrohydrobupropion, which are formed via reduction of the carbonyl group. In vitro findings suggest that CYP2B6 is the principal isoenzyme involved in the formation of hydroxybupropion, while cytochrome P450 enzymes are not involved in the formation of threohydrobupropion. Hydroxybupropion has been shown to have the same affinity as bupropion for the norepinephrine transporter (NET) but approximately 50% of its antidepressant activity despite reaching concentrations of ~10-fold higher than that of the parent drug. Oxidation of the bupropion side chain results in the formation of a glycine conjugate of meta-chlorobenzoic acid, which is then excreted as the major urinary metabolite. The potency and toxicity of the metabolites relative to bupropion have not been fully characterized. However, it has been demonstrated in an antidepressant screening test in mice that hydroxybupropion is one-half as potent as bupropion, while threohydrobupropion and erythrohydrobupropion are 5-fold less potent than bupropion. This may be of clinical importance because the plasma concentrations of the metabolites are as high as or higher than those of bupropion. Bupropion and its metabolites exhibit linear kinetics following chronic administration of 300 to 450 mg per day. •Metabolism (Drug B): No metabolism available •Route of elimination (Drug A): Bupropion is extensively metabolized in humans. Oxidation of the bupropion side chain results in the formation of a glycine conjugate of metachlorobenzoic acid, which is then excreted as the major urinary metabolite. Following oral administration of 200 mg of 14C-bupropion in humans, 87% and 10% of the radioactive dose were recovered in the urine and feces, respectively. However, the fraction of the oral dose of bupropion excreted unchanged was only 0.5%, a finding consistent with the extensive metabolism of bupropion. •Route of elimination (Drug B): No route of elimination available •Half-life (Drug A): 24 hours •Half-life (Drug B): No half-life available •Clearance (Drug A): No clearance available •Clearance (Drug B): No clearance available •Toxicity (Drug A): Symptoms of overdose include seizures, hallucinations, loss of consciousness, tachycardia, and cardiac arrest. •Toxicity (Drug B): No toxicity available •Brand Names (Drug A): Aplenzin, Auvelity, Budeprion, Contrave, Forfivo, Wellbutrin, Zyban •Brand Names (Drug B): No brand names available •Synonyms (Drug A): No synonyms listed •Synonyms (Drug B): alpha-Narcotine Noscapina Noscapine Noscapinum •Summary (Drug A): Bupropion is a norepinephrine and dopamine reuptake inhibitor used in the treatment of major depressive disorder (MDD), seasonal affective disorder (SAD), and as an aid to smoking cessation. •Summary (Drug B): Noscapine is a non-sedating isoquinoline alkaloid used primarily for its antitussive properties.

The subject drug is known to be an inhibitor of CYP2C9 while the affected drug is reported to be metabolized by CYP2C9. Concomitant administration of these agents can cause an increase in the serum concentration of the affected drug due to decreased metabolism by CYP2C9, which may result in increased incidence and/or severity of adverse effects related to the affected drug. The severity of the interaction is moderate.

Question: Does Bupropion and Noscapine interact? Information: •Drug A: Bupropion •Drug B: Noscapine •Severity: MODERATE •Description: The metabolism of Bupropion can be decreased when combined with Noscapine. •Extended Description: The subject drug is known to be an inhibitor of CYP2C9 while the affected drug is reported to be metabolized by CYP2C9. Concomitant administration of these agents can cause an increase in the serum concentration of the affected drug due to decreased metabolism by CYP2C9, which may result in increased incidence and/or severity of adverse effects related to the affected drug. •Indication (Drug A): Bupropion is indicated for the treatment of major depressive disorder (MDD), seasonal affective disorder (SAD), and as an aid to smoking cessation. When used in combination with naltrexone as the marketed product ContraveⓇ, bupropion is indicated as an adjunct to a reduced-calorie diet and increased physical activity for chronic weight management in adults with an initial body mass index (BMI) of: 30 kg/m^2 or greater (obese) or 27 kg/m^2 or greater (overweight) in the presence of at least one weight-related comorbid condition (e.g., hypertension, type 2 diabetes mellitus, or dyslipidemia). Bupropion is also used off-label as a first-line treatment in patients with ADHD and comorbid bipolar disorder when used as an adjunct to mood stabilizers. •Indication (Drug B): Investigated for use/treatment in lymphoma (non-hodgkin's), leukemia (lymphoid), cancer/tumors (unspecified), and multiple myeloma. •Pharmacodynamics (Drug A): Bupropion is chemically unrelated to tricyclic, tetracyclic, selective serotonin re-uptake inhibitors, or other known antidepressant agents. Compared to classical tricyclic antidepressants, Bupropion is a relatively weak inhibitor of the neuronal uptake of norepinephrine and dopamine. In addition, Bupropion does not inhibit monoamine oxidase. Bupropion has been found to be essentially inactive at the serotonin transporter (SERT)(IC50 >10 000 nM), however both bupropion and its primary metabolite hydroxybupropion have been found to block the function of cation-selective serotonin type 3A receptors (5-HT3ARs). Bupropion produces dose-related central nervous system (CNS) stimulant effects in animals, as evidenced by increased locomotor activity, increased rates of responding in various schedule-controlled operant behaviour tasks, and, at high doses, induction of mild stereotyped behaviour. Due to these stimulant effects and selective activity at dopamine and norepinephrine receptors, bupropion has been identified as having an abuse potential. Bupropion has a similar structure to the controlled substance Cathinone, and has been identified as having mild amphetamine-like activity, particularly when inhaled or injected. Bupropion is also known to lower the seizure threshold, making any pre-existing seizure conditions a contraindication to its use. This risk is exacerbated when bupropion is combined with other drugs or substances that lower the seizure threshold, such as cocaine, or in clinical situations that would increase the risk of a seizure such as abrupt alcohol or benzodiazepine withdrawal. As norepinephrine has been shown to have anticonvulsant properties, bupropion's inhibitory effects on NET are thought to contribute to its pro-convulsant activity. Bupropion has been shown to increase blood pressure and pose a risk for exacerbation of unmanaged or pre-existing hypertension, however, clinical trials of bupropion in smokers with CVD have not identified an increased incidence of CV events including stroke or heart attack. In clinical trials, the mean increase in systolic blood pressure associated with the use of bupropion was found to be 1.3 mmHg. •Pharmacodynamics (Drug B): No pharmacodynamics available •Mechanism of action (Drug A): Bupropion is a norepinephrine/dopamine-reuptake inhibitor (NDRI) that exerts its pharmacological effects by weakly inhibiting the enzymes involved in the uptake of the neurotransmitters norepinephrine and dopamine from the synaptic cleft, therefore prolonging their duration of action within the neuronal synapse and the downstream effects of these neurotransmitters. More specifically, bupropion binds to the norepinephrine transporter (NET) and the dopamine transporter (DAT). Bupropion was originally classified as an "atypical" antidepressant because it does not exert the same effects as the classical antidepressants such as Monoamine Oxidase Inhibitors (MAOIs), Tricyclic Antidepressants (TCAs), or Selective Serotonin Reuptake Inhibitors (SSRIs). While it has comparable effectiveness to typical first-line options for the treatment of depression such as SSRIs, bupropion is a unique option for the treatment of MDD as it lacks any clinically relevant serotonergic effects, typical of other mood medications, or any effects on histamine or adrenaline receptors. Lack of activity at these receptors results in a more tolerable side effect profile; bupropion is less likely to cause sexual side effects, sedation, or weight gain as compared to SSRIs or TCAs, for example. When used as an aid to smoking cessation, bupropion is thought to confer its anti-craving and anti-withdrawal effects by inhibiting dopamine reuptake, which is thought to be involved in the reward pathways associated with nicotine, and through the antagonism of the nicotinic acetylcholinergic receptor (AChR), thereby blunting the effects of nicotine. Furthermore, the stimulatory effects produced by bupropion in the central nervous system are similar to nicotine's effects, making low doses of bupropion a suitable option as a nicotine substitute. When used in combination with naltrexone in the marketed product ContraveⓇ for chronic weight management, the two components are thought to have effects on areas of the brain involved in the regulation of food intake. This includes the hypothalamus, which is involved in appetite regulation, and the mesolimbic dopamine circuit, which is involved in reward pathways. Studies have shown that the combined activity of bupropion and naltrexone increase the firing rate of hypothalamic pro-opiomelanocortin (POMC) neurons and blockade of opioid receptor-mediated POMC auto-inhibition, which are associated with a reduction in food intake and increased energy expenditure. This combination was also found to reduce food intake when injected directly into the ventral tegmental area of the mesolimbic circuit in mice, which is an area associated with the regulation of reward pathways. •Mechanism of action (Drug B): Noscapine's antitussive effects appear to be primarily mediated by its sigma receptor agonist activity. Evidence for this mechanism is suggested by experimental evidence in rats. Pretreatment with rimcazole, a sigma specific antagonist, causes a dose-dependent reduction in antitussive activity of noscapine. •Absorption (Drug A): Bupropion is currently available in 3 distinct, but bioequivalent formulations: immediate release (IR), sustained-release (SR), and extended-release (XL). Immediate Release Formulation In humans, following oral administration of bupropion hydrochloride tablets, peak plasma bupropion concentrations are usually achieved within 2 hours. IR formulations provide a short duration of action and are therefore generally dosed three times per day. Sustained Release Formulation In humans, following oral administration of bupropion hydrochloride sustained-release tablets (SR), peak plasma concentration (Cmax) of bupropion is usually achieved within 3 hours. SR formulations provide a 12-hour extended release of medication and are therefore generally dosed twice per day. Extended Release Formulation Following single oral administration of bupropion hydrochloride extended-release tablets (XL) to healthy volunteers, the median time to peak plasma concentrations for bupropion was approximately 5 hours. The presence of food did not affect the peak concentration or area under the curve of bupropion. XL formulations provide a 24-hour extended release of medication and are therefore generally dosed once per day/ In a trial comparing chronic dosing with bupropion hydrochloride extended-release tablets (SR) 150 mg twice daily to bupropion immediate-release formulation 100 mg 3 times daily, the steady state Cmax for bupropion after bupropion hydrochloride sustained-release tablets (SR) administration was approximately 85% of those achieved after bupropion immediate-release formulation administration. Exposure (AUC) to bupropion was equivalent for both formulations. Bioequivalence was also demonstrated for all three major active metabolites (i.e., hydroxybupropion, threohydrobupropion and erythrohydrobupropion) for both Cmax and AUC. Thus, at steady state, bupropion hydrochloride sustained-release tablets (SR) given twice daily, and the immediate-release formulation of bupropion given 3 times daily, are essentially bioequivalent for both bupropion and the 3 quantitatively important metabolites. Furthermore, in a study comparing 14-day dosing with bupropion hydrochloride extended-release tablets (XL), 300 mg once-daily to the immediate-release formulation of bupropion at 100 mg 3 times daily, equivalence was demonstrated for peak plasma concentration and area under the curve for bupropion and the three metabolites (hydroxybupropion, threohydrobupropion, and erythrohydrobupropion). Additionally, in a study comparing 14-day dosing with bupropion hydrochloride extended-release tablets (XL) 300 mg once daily to the sustained-release formulation of bupropion at 150 mg 2 times daily, equivalence was demonstrated for peak plasma concentration and area under the curve for bupropion and the three metabolites. Bupropion hydrochloride extended-release tablets (SR) can be taken with or without food. Bupropion Cmax and AUC were increased by 11% to 35% and 16% to 19%, respectively, when bupropion hydrochloride extended-release tablets (SR) was administered with food to healthy volunteers in three trials. The food effect is not considered clinically significant. Following a single-dose administration of bupropion hydrochloride extended-release tablets (SR) in humans, Cmax of bupropion's metabolite hydroxybupropion occurs approximately 6 hours post-dose and is approximately 10 times the peak level of the parent drug at steady state. The elimination half-life of hydroxybupropion is approximately 20 (±5) hours and its AUC at steady state is about 17 times that of bupropion. The times to peak concentrations for the erythrohydrobupropion and threohydrobupropion metabolites are similar to that of the hydroxybupropion metabolite. However, their elimination half-lives are longer, 33(±10) and 37 (±13) hours, respectively, and steady-state AUCs are 1.5 and 7 times that of bupropion, respectively. •Absorption (Drug B): No absorption available •Volume of distribution (Drug A): No volume of distribution available •Volume of distribution (Drug B): No volume of distribution available •Protein binding (Drug A): In vitro tests show that bupropion is 84% bound to human plasma proteins at concentrations up to 200 mcg per mL. The extent of protein binding of the hydroxybupropion metabolite is similar to that for bupropion, whereas the extent of protein binding of the threohydrobupropion metabolite is about half that seen with bupropion. •Protein binding (Drug B): No protein binding available •Metabolism (Drug A): Bupropion is extensively metabolized in humans. Three metabolites are active: hydroxybupropion, which is formed via hydroxylation of the tert-butyl group of bupropion, and the amino-alcohol isomers, threohydrobupropion and erythrohydrobupropion, which are formed via reduction of the carbonyl group. In vitro findings suggest that CYP2B6 is the principal isoenzyme involved in the formation of hydroxybupropion, while cytochrome P450 enzymes are not involved in the formation of threohydrobupropion. Hydroxybupropion has been shown to have the same affinity as bupropion for the norepinephrine transporter (NET) but approximately 50% of its antidepressant activity despite reaching concentrations of ~10-fold higher than that of the parent drug. Oxidation of the bupropion side chain results in the formation of a glycine conjugate of meta-chlorobenzoic acid, which is then excreted as the major urinary metabolite. The potency and toxicity of the metabolites relative to bupropion have not been fully characterized. However, it has been demonstrated in an antidepressant screening test in mice that hydroxybupropion is one-half as potent as bupropion, while threohydrobupropion and erythrohydrobupropion are 5-fold less potent than bupropion. This may be of clinical importance because the plasma concentrations of the metabolites are as high as or higher than those of bupropion. Bupropion and its metabolites exhibit linear kinetics following chronic administration of 300 to 450 mg per day. •Metabolism (Drug B): No metabolism available •Route of elimination (Drug A): Bupropion is extensively metabolized in humans. Oxidation of the bupropion side chain results in the formation of a glycine conjugate of metachlorobenzoic acid, which is then excreted as the major urinary metabolite. Following oral administration of 200 mg of 14C-bupropion in humans, 87% and 10% of the radioactive dose were recovered in the urine and feces, respectively. However, the fraction of the oral dose of bupropion excreted unchanged was only 0.5%, a finding consistent with the extensive metabolism of bupropion. •Route of elimination (Drug B): No route of elimination available •Half-life (Drug A): 24 hours •Half-life (Drug B): No half-life available •Clearance (Drug A): No clearance available •Clearance (Drug B): No clearance available •Toxicity (Drug A): Symptoms of overdose include seizures, hallucinations, loss of consciousness, tachycardia, and cardiac arrest. •Toxicity (Drug B): No toxicity available •Brand Names (Drug A): Aplenzin, Auvelity, Budeprion, Contrave, Forfivo, Wellbutrin, Zyban •Brand Names (Drug B): No brand names available •Synonyms (Drug A): No synonyms listed •Synonyms (Drug B): alpha-Narcotine Noscapina Noscapine Noscapinum •Summary (Drug A): Bupropion is a norepinephrine and dopamine reuptake inhibitor used in the treatment of major depressive disorder (MDD), seasonal affective disorder (SAD), and as an aid to smoking cessation. •Summary (Drug B): Noscapine is a non-sedating isoquinoline alkaloid used primarily for its antitussive properties. Output: The subject drug is known to be an inhibitor of CYP2C9 while the affected drug is reported to be metabolized by CYP2C9. Concomitant administration of these agents can cause an increase in the serum concentration of the affected drug due to decreased metabolism by CYP2C9, which may result in increased incidence and/or severity of adverse effects related to the affected drug. The severity of the interaction is moderate.

Does Bupropion and Octinoxate interact?

•Drug A: Bupropion •Drug B: Octinoxate •Severity: MINOR •Description: Bupropion may decrease the excretion rate of Octinoxate which could result in a higher serum level. •Extended Description: The renal excretion of drugs is the overall result of a combination of kidney processes that include glomerular filtration, passive diffusion, tubular secretion, and tubular reabsorption. Since two of these mechanisms - tubular secretion and reabsorption - are saturable processes , they are consequently susceptible to competition between multiple substrates excreted by the kidneys. If two or more medications that are mainly renally excreted are co-administered, they may compete for renal elimination; there is a large likelihood that one agent may "out-compete" or saturate the renal excretion mechanisms before the other concomitantly administered agent(s) are excreted. As a result, the elimination of these other concurrently administered agents may be inhibited or otherwise delayed, which could lead to increases in their serum concentrations and the risk, incidence, and/or severity of adverse effects associated with the exposure to such drugs. •Indication (Drug A): Bupropion is indicated for the treatment of major depressive disorder (MDD), seasonal affective disorder (SAD), and as an aid to smoking cessation. When used in combination with naltrexone as the marketed product ContraveⓇ, bupropion is indicated as an adjunct to a reduced-calorie diet and increased physical activity for chronic weight management in adults with an initial body mass index (BMI) of: 30 kg/m^2 or greater (obese) or 27 kg/m^2 or greater (overweight) in the presence of at least one weight-related comorbid condition (e.g., hypertension, type 2 diabetes mellitus, or dyslipidemia). Bupropion is also used off-label as a first-line treatment in patients with ADHD and comorbid bipolar disorder when used as an adjunct to mood stabilizers. •Indication (Drug B): As an active ingredient in sunscreens and lip balms. Used for protection against damaging effects of sun rays. •Pharmacodynamics (Drug A): Bupropion is chemically unrelated to tricyclic, tetracyclic, selective serotonin re-uptake inhibitors, or other known antidepressant agents. Compared to classical tricyclic antidepressants, Bupropion is a relatively weak inhibitor of the neuronal uptake of norepinephrine and dopamine. In addition, Bupropion does not inhibit monoamine oxidase. Bupropion has been found to be essentially inactive at the serotonin transporter (SERT)(IC50 >10 000 nM), however both bupropion and its primary metabolite hydroxybupropion have been found to block the function of cation-selective serotonin type 3A receptors (5-HT3ARs). Bupropion produces dose-related central nervous system (CNS) stimulant effects in animals, as evidenced by increased locomotor activity, increased rates of responding in various schedule-controlled operant behaviour tasks, and, at high doses, induction of mild stereotyped behaviour. Due to these stimulant effects and selective activity at dopamine and norepinephrine receptors, bupropion has been identified as having an abuse potential. Bupropion has a similar structure to the controlled substance Cathinone, and has been identified as having mild amphetamine-like activity, particularly when inhaled or injected. Bupropion is also known to lower the seizure threshold, making any pre-existing seizure conditions a contraindication to its use. This risk is exacerbated when bupropion is combined with other drugs or substances that lower the seizure threshold, such as cocaine, or in clinical situations that would increase the risk of a seizure such as abrupt alcohol or benzodiazepine withdrawal. As norepinephrine has been shown to have anticonvulsant properties, bupropion's inhibitory effects on NET are thought to contribute to its pro-convulsant activity. Bupropion has been shown to increase blood pressure and pose a risk for exacerbation of unmanaged or pre-existing hypertension, however, clinical trials of bupropion in smokers with CVD have not identified an increased incidence of CV events including stroke or heart attack. In clinical trials, the mean increase in systolic blood pressure associated with the use of bupropion was found to be 1.3 mmHg. •Pharmacodynamics (Drug B): Acts as a photoprotective agent that protects the skin by preventing and minimizing the damaging effects of ultraviolet (UV) rays of natural light. The cellular effects of UV irradiation include DNA damage, cell cycle arrest, immunological depression, apoptosis, and transcriptional changes. •Mechanism of action (Drug A): Bupropion is a norepinephrine/dopamine-reuptake inhibitor (NDRI) that exerts its pharmacological effects by weakly inhibiting the enzymes involved in the uptake of the neurotransmitters norepinephrine and dopamine from the synaptic cleft, therefore prolonging their duration of action within the neuronal synapse and the downstream effects of these neurotransmitters. More specifically, bupropion binds to the norepinephrine transporter (NET) and the dopamine transporter (DAT). Bupropion was originally classified as an "atypical" antidepressant because it does not exert the same effects as the classical antidepressants such as Monoamine Oxidase Inhibitors (MAOIs), Tricyclic Antidepressants (TCAs), or Selective Serotonin Reuptake Inhibitors (SSRIs). While it has comparable effectiveness to typical first-line options for the treatment of depression such as SSRIs, bupropion is a unique option for the treatment of MDD as it lacks any clinically relevant serotonergic effects, typical of other mood medications, or any effects on histamine or adrenaline receptors. Lack of activity at these receptors results in a more tolerable side effect profile; bupropion is less likely to cause sexual side effects, sedation, or weight gain as compared to SSRIs or TCAs, for example. When used as an aid to smoking cessation, bupropion is thought to confer its anti-craving and anti-withdrawal effects by inhibiting dopamine reuptake, which is thought to be involved in the reward pathways associated with nicotine, and through the antagonism of the nicotinic acetylcholinergic receptor (AChR), thereby blunting the effects of nicotine. Furthermore, the stimulatory effects produced by bupropion in the central nervous system are similar to nicotine's effects, making low doses of bupropion a suitable option as a nicotine substitute. When used in combination with naltrexone in the marketed product ContraveⓇ for chronic weight management, the two components are thought to have effects on areas of the brain involved in the regulation of food intake. This includes the hypothalamus, which is involved in appetite regulation, and the mesolimbic dopamine circuit, which is involved in reward pathways. Studies have shown that the combined activity of bupropion and naltrexone increase the firing rate of hypothalamic pro-opiomelanocortin (POMC) neurons and blockade of opioid receptor-mediated POMC auto-inhibition, which are associated with a reduction in food intake and increased energy expenditure. This combination was also found to reduce food intake when injected directly into the ventral tegmental area of the mesolimbic circuit in mice, which is an area associated with the regulation of reward pathways. •Mechanism of action (Drug B): Absorbs UV-B (predominantly) and UV-A rays while accumulating in the outermost layer of the epidermis. Like any other photoprotective agents, octinoxate prevents the damage to cells and deoxyribonucleic acid (DNA) by reducing the p53 protein expression following UV exposure and also increases the skin's tolerability to UV rays. •Absorption (Drug A): Bupropion is currently available in 3 distinct, but bioequivalent formulations: immediate release (IR), sustained-release (SR), and extended-release (XL). Immediate Release Formulation In humans, following oral administration of bupropion hydrochloride tablets, peak plasma bupropion concentrations are usually achieved within 2 hours. IR formulations provide a short duration of action and are therefore generally dosed three times per day. Sustained Release Formulation In humans, following oral administration of bupropion hydrochloride sustained-release tablets (SR), peak plasma concentration (Cmax) of bupropion is usually achieved within 3 hours. SR formulations provide a 12-hour extended release of medication and are therefore generally dosed twice per day. Extended Release Formulation Following single oral administration of bupropion hydrochloride extended-release tablets (XL) to healthy volunteers, the median time to peak plasma concentrations for bupropion was approximately 5 hours. The presence of food did not affect the peak concentration or area under the curve of bupropion. XL formulations provide a 24-hour extended release of medication and are therefore generally dosed once per day/ In a trial comparing chronic dosing with bupropion hydrochloride extended-release tablets (SR) 150 mg twice daily to bupropion immediate-release formulation 100 mg 3 times daily, the steady state Cmax for bupropion after bupropion hydrochloride sustained-release tablets (SR) administration was approximately 85% of those achieved after bupropion immediate-release formulation administration. Exposure (AUC) to bupropion was equivalent for both formulations. Bioequivalence was also demonstrated for all three major active metabolites (i.e., hydroxybupropion, threohydrobupropion and erythrohydrobupropion) for both Cmax and AUC. Thus, at steady state, bupropion hydrochloride sustained-release tablets (SR) given twice daily, and the immediate-release formulation of bupropion given 3 times daily, are essentially bioequivalent for both bupropion and the 3 quantitatively important metabolites. Furthermore, in a study comparing 14-day dosing with bupropion hydrochloride extended-release tablets (XL), 300 mg once-daily to the immediate-release formulation of bupropion at 100 mg 3 times daily, equivalence was demonstrated for peak plasma concentration and area under the curve for bupropion and the three metabolites (hydroxybupropion, threohydrobupropion, and erythrohydrobupropion). Additionally, in a study comparing 14-day dosing with bupropion hydrochloride extended-release tablets (XL) 300 mg once daily to the sustained-release formulation of bupropion at 150 mg 2 times daily, equivalence was demonstrated for peak plasma concentration and area under the curve for bupropion and the three metabolites. Bupropion hydrochloride extended-release tablets (SR) can be taken with or without food. Bupropion Cmax and AUC were increased by 11% to 35% and 16% to 19%, respectively, when bupropion hydrochloride extended-release tablets (SR) was administered with food to healthy volunteers in three trials. The food effect is not considered clinically significant. Following a single-dose administration of bupropion hydrochloride extended-release tablets (SR) in humans, Cmax of bupropion's metabolite hydroxybupropion occurs approximately 6 hours post-dose and is approximately 10 times the peak level of the parent drug at steady state. The elimination half-life of hydroxybupropion is approximately 20 (±5) hours and its AUC at steady state is about 17 times that of bupropion. The times to peak concentrations for the erythrohydrobupropion and threohydrobupropion metabolites are similar to that of the hydroxybupropion metabolite. However, their elimination half-lives are longer, 33(±10) and 37 (±13) hours, respectively, and steady-state AUCs are 1.5 and 7 times that of bupropion, respectively. •Absorption (Drug B): Can be systemically absorbed after skin application, being found in the deeper layers of the stratum corneum as well as urine, plasma, and breast milk. The mean maximum plasma concentration detected after application of 2mg/cm2 sunscreen was 7ng/mL in women and 16ng/mL in men. •Volume of distribution (Drug A): No volume of distribution available •Volume of distribution (Drug B): No volume of distribution available •Protein binding (Drug A): In vitro tests show that bupropion is 84% bound to human plasma proteins at concentrations up to 200 mcg per mL. The extent of protein binding of the hydroxybupropion metabolite is similar to that for bupropion, whereas the extent of protein binding of the threohydrobupropion metabolite is about half that seen with bupropion. •Metabolism (Drug A): Bupropion is extensively metabolized in humans. Three metabolites are active: hydroxybupropion, which is formed via hydroxylation of the tert-butyl group of bupropion, and the amino-alcohol isomers, threohydrobupropion and erythrohydrobupropion, which are formed via reduction of the carbonyl group. In vitro findings suggest that CYP2B6 is the principal isoenzyme involved in the formation of hydroxybupropion, while cytochrome P450 enzymes are not involved in the formation of threohydrobupropion. Hydroxybupropion has been shown to have the same affinity as bupropion for the norepinephrine transporter (NET) but approximately 50% of its antidepressant activity despite reaching concentrations of ~10-fold higher than that of the parent drug. Oxidation of the bupropion side chain results in the formation of a glycine conjugate of meta-chlorobenzoic acid, which is then excreted as the major urinary metabolite. The potency and toxicity of the metabolites relative to bupropion have not been fully characterized. However, it has been demonstrated in an antidepressant screening test in mice that hydroxybupropion is one-half as potent as bupropion, while threohydrobupropion and erythrohydrobupropion are 5-fold less potent than bupropion. This may be of clinical importance because the plasma concentrations of the metabolites are as high as or higher than those of bupropion. Bupropion and its metabolites exhibit linear kinetics following chronic administration of 300 to 450 mg per day. •Metabolism (Drug B): Can undergo hepatic metabolism when systematically absorbed. Can be enzymatically degraded by lipases in the stratum corneum where esters undergo hydrolysis. Degrade into photoproducts when exposed to sunlight, which leads to a decrease in UV absorption efficiency. •Route of elimination (Drug A): Bupropion is extensively metabolized in humans. Oxidation of the bupropion side chain results in the formation of a glycine conjugate of metachlorobenzoic acid, which is then excreted as the major urinary metabolite. Following oral administration of 200 mg of 14C-bupropion in humans, 87% and 10% of the radioactive dose were recovered in the urine and feces, respectively. However, the fraction of the oral dose of bupropion excreted unchanged was only 0.5%, a finding consistent with the extensive metabolism of bupropion. •Route of elimination (Drug B): Can be detected in urine in unchanged form. •Half-life (Drug A): 24 hours •Half-life (Drug B): No half-life available •Clearance (Drug A): No clearance available •Clearance (Drug B): No clearance available •Toxicity (Drug A): Symptoms of overdose include seizures, hallucinations, loss of consciousness, tachycardia, and cardiac arrest. •Toxicity (Drug B): Slightly hazardous in case of skin contact, eye contact, ingestion and inhalation. Octinoxate may form reactive singlet oxygen species and induce anti-estrogenic effects. UV-induced molecular breakdown of octinoxate may interfere with cellular processes or induce oxidative damage in human skin. The NOAEL (no observed adverse effect level) is 450 mg/kg bw/day for fertility and reproductive performance, for systemic parental and developmental toxicity in Wistar rats. •Brand Names (Drug A): Aplenzin, Auvelity, Budeprion, Contrave, Forfivo, Wellbutrin, Zyban •Brand Names (Drug B): Eucerin, Meijer, Sumadan Wash •Synonyms (Drug A): No synonyms listed •Synonyms (Drug B): No synonyms listed •Summary (Drug A): Bupropion is a norepinephrine and dopamine reuptake inhibitor used in the treatment of major depressive disorder (MDD), seasonal affective disorder (SAD), and as an aid to smoking cessation. •Summary (Drug B): Octinoxate is a sunscreen agent found in sunscreens that absorbs UV rays.

The renal excretion of drugs is the overall result of a combination of kidney processes that include glomerular filtration, passive diffusion, tubular secretion, and tubular reabsorption. Since two of these mechanisms - tubular secretion and reabsorption - are saturable processes , they are consequently susceptible to competition between multiple substrates excreted by the kidneys. If two or more medications that are mainly renally excreted are co-administered, they may compete for renal elimination; there is a large likelihood that one agent may "out-compete" or saturate the renal excretion mechanisms before the other concomitantly administered agent(s) are excreted. As a result, the elimination of these other concurrently administered agents may be inhibited or otherwise delayed, which could lead to increases in their serum concentrations and the risk, incidence, and/or severity of adverse effects associated with the exposure to such drugs. The severity of the interaction is minor.

Question: Does Bupropion and Octinoxate interact? Information: •Drug A: Bupropion •Drug B: Octinoxate •Severity: MINOR •Description: Bupropion may decrease the excretion rate of Octinoxate which could result in a higher serum level. •Extended Description: The renal excretion of drugs is the overall result of a combination of kidney processes that include glomerular filtration, passive diffusion, tubular secretion, and tubular reabsorption. Since two of these mechanisms - tubular secretion and reabsorption - are saturable processes , they are consequently susceptible to competition between multiple substrates excreted by the kidneys. If two or more medications that are mainly renally excreted are co-administered, they may compete for renal elimination; there is a large likelihood that one agent may "out-compete" or saturate the renal excretion mechanisms before the other concomitantly administered agent(s) are excreted. As a result, the elimination of these other concurrently administered agents may be inhibited or otherwise delayed, which could lead to increases in their serum concentrations and the risk, incidence, and/or severity of adverse effects associated with the exposure to such drugs. •Indication (Drug A): Bupropion is indicated for the treatment of major depressive disorder (MDD), seasonal affective disorder (SAD), and as an aid to smoking cessation. When used in combination with naltrexone as the marketed product ContraveⓇ, bupropion is indicated as an adjunct to a reduced-calorie diet and increased physical activity for chronic weight management in adults with an initial body mass index (BMI) of: 30 kg/m^2 or greater (obese) or 27 kg/m^2 or greater (overweight) in the presence of at least one weight-related comorbid condition (e.g., hypertension, type 2 diabetes mellitus, or dyslipidemia). Bupropion is also used off-label as a first-line treatment in patients with ADHD and comorbid bipolar disorder when used as an adjunct to mood stabilizers. •Indication (Drug B): As an active ingredient in sunscreens and lip balms. Used for protection against damaging effects of sun rays. •Pharmacodynamics (Drug A): Bupropion is chemically unrelated to tricyclic, tetracyclic, selective serotonin re-uptake inhibitors, or other known antidepressant agents. Compared to classical tricyclic antidepressants, Bupropion is a relatively weak inhibitor of the neuronal uptake of norepinephrine and dopamine. In addition, Bupropion does not inhibit monoamine oxidase. Bupropion has been found to be essentially inactive at the serotonin transporter (SERT)(IC50 >10 000 nM), however both bupropion and its primary metabolite hydroxybupropion have been found to block the function of cation-selective serotonin type 3A receptors (5-HT3ARs). Bupropion produces dose-related central nervous system (CNS) stimulant effects in animals, as evidenced by increased locomotor activity, increased rates of responding in various schedule-controlled operant behaviour tasks, and, at high doses, induction of mild stereotyped behaviour. Due to these stimulant effects and selective activity at dopamine and norepinephrine receptors, bupropion has been identified as having an abuse potential. Bupropion has a similar structure to the controlled substance Cathinone, and has been identified as having mild amphetamine-like activity, particularly when inhaled or injected. Bupropion is also known to lower the seizure threshold, making any pre-existing seizure conditions a contraindication to its use. This risk is exacerbated when bupropion is combined with other drugs or substances that lower the seizure threshold, such as cocaine, or in clinical situations that would increase the risk of a seizure such as abrupt alcohol or benzodiazepine withdrawal. As norepinephrine has been shown to have anticonvulsant properties, bupropion's inhibitory effects on NET are thought to contribute to its pro-convulsant activity. Bupropion has been shown to increase blood pressure and pose a risk for exacerbation of unmanaged or pre-existing hypertension, however, clinical trials of bupropion in smokers with CVD have not identified an increased incidence of CV events including stroke or heart attack. In clinical trials, the mean increase in systolic blood pressure associated with the use of bupropion was found to be 1.3 mmHg. •Pharmacodynamics (Drug B): Acts as a photoprotective agent that protects the skin by preventing and minimizing the damaging effects of ultraviolet (UV) rays of natural light. The cellular effects of UV irradiation include DNA damage, cell cycle arrest, immunological depression, apoptosis, and transcriptional changes. •Mechanism of action (Drug A): Bupropion is a norepinephrine/dopamine-reuptake inhibitor (NDRI) that exerts its pharmacological effects by weakly inhibiting the enzymes involved in the uptake of the neurotransmitters norepinephrine and dopamine from the synaptic cleft, therefore prolonging their duration of action within the neuronal synapse and the downstream effects of these neurotransmitters. More specifically, bupropion binds to the norepinephrine transporter (NET) and the dopamine transporter (DAT). Bupropion was originally classified as an "atypical" antidepressant because it does not exert the same effects as the classical antidepressants such as Monoamine Oxidase Inhibitors (MAOIs), Tricyclic Antidepressants (TCAs), or Selective Serotonin Reuptake Inhibitors (SSRIs). While it has comparable effectiveness to typical first-line options for the treatment of depression such as SSRIs, bupropion is a unique option for the treatment of MDD as it lacks any clinically relevant serotonergic effects, typical of other mood medications, or any effects on histamine or adrenaline receptors. Lack of activity at these receptors results in a more tolerable side effect profile; bupropion is less likely to cause sexual side effects, sedation, or weight gain as compared to SSRIs or TCAs, for example. When used as an aid to smoking cessation, bupropion is thought to confer its anti-craving and anti-withdrawal effects by inhibiting dopamine reuptake, which is thought to be involved in the reward pathways associated with nicotine, and through the antagonism of the nicotinic acetylcholinergic receptor (AChR), thereby blunting the effects of nicotine. Furthermore, the stimulatory effects produced by bupropion in the central nervous system are similar to nicotine's effects, making low doses of bupropion a suitable option as a nicotine substitute. When used in combination with naltrexone in the marketed product ContraveⓇ for chronic weight management, the two components are thought to have effects on areas of the brain involved in the regulation of food intake. This includes the hypothalamus, which is involved in appetite regulation, and the mesolimbic dopamine circuit, which is involved in reward pathways. Studies have shown that the combined activity of bupropion and naltrexone increase the firing rate of hypothalamic pro-opiomelanocortin (POMC) neurons and blockade of opioid receptor-mediated POMC auto-inhibition, which are associated with a reduction in food intake and increased energy expenditure. This combination was also found to reduce food intake when injected directly into the ventral tegmental area of the mesolimbic circuit in mice, which is an area associated with the regulation of reward pathways. •Mechanism of action (Drug B): Absorbs UV-B (predominantly) and UV-A rays while accumulating in the outermost layer of the epidermis. Like any other photoprotective agents, octinoxate prevents the damage to cells and deoxyribonucleic acid (DNA) by reducing the p53 protein expression following UV exposure and also increases the skin's tolerability to UV rays. •Absorption (Drug A): Bupropion is currently available in 3 distinct, but bioequivalent formulations: immediate release (IR), sustained-release (SR), and extended-release (XL). Immediate Release Formulation In humans, following oral administration of bupropion hydrochloride tablets, peak plasma bupropion concentrations are usually achieved within 2 hours. IR formulations provide a short duration of action and are therefore generally dosed three times per day. Sustained Release Formulation In humans, following oral administration of bupropion hydrochloride sustained-release tablets (SR), peak plasma concentration (Cmax) of bupropion is usually achieved within 3 hours. SR formulations provide a 12-hour extended release of medication and are therefore generally dosed twice per day. Extended Release Formulation Following single oral administration of bupropion hydrochloride extended-release tablets (XL) to healthy volunteers, the median time to peak plasma concentrations for bupropion was approximately 5 hours. The presence of food did not affect the peak concentration or area under the curve of bupropion. XL formulations provide a 24-hour extended release of medication and are therefore generally dosed once per day/ In a trial comparing chronic dosing with bupropion hydrochloride extended-release tablets (SR) 150 mg twice daily to bupropion immediate-release formulation 100 mg 3 times daily, the steady state Cmax for bupropion after bupropion hydrochloride sustained-release tablets (SR) administration was approximately 85% of those achieved after bupropion immediate-release formulation administration. Exposure (AUC) to bupropion was equivalent for both formulations. Bioequivalence was also demonstrated for all three major active metabolites (i.e., hydroxybupropion, threohydrobupropion and erythrohydrobupropion) for both Cmax and AUC. Thus, at steady state, bupropion hydrochloride sustained-release tablets (SR) given twice daily, and the immediate-release formulation of bupropion given 3 times daily, are essentially bioequivalent for both bupropion and the 3 quantitatively important metabolites. Furthermore, in a study comparing 14-day dosing with bupropion hydrochloride extended-release tablets (XL), 300 mg once-daily to the immediate-release formulation of bupropion at 100 mg 3 times daily, equivalence was demonstrated for peak plasma concentration and area under the curve for bupropion and the three metabolites (hydroxybupropion, threohydrobupropion, and erythrohydrobupropion). Additionally, in a study comparing 14-day dosing with bupropion hydrochloride extended-release tablets (XL) 300 mg once daily to the sustained-release formulation of bupropion at 150 mg 2 times daily, equivalence was demonstrated for peak plasma concentration and area under the curve for bupropion and the three metabolites. Bupropion hydrochloride extended-release tablets (SR) can be taken with or without food. Bupropion Cmax and AUC were increased by 11% to 35% and 16% to 19%, respectively, when bupropion hydrochloride extended-release tablets (SR) was administered with food to healthy volunteers in three trials. The food effect is not considered clinically significant. Following a single-dose administration of bupropion hydrochloride extended-release tablets (SR) in humans, Cmax of bupropion's metabolite hydroxybupropion occurs approximately 6 hours post-dose and is approximately 10 times the peak level of the parent drug at steady state. The elimination half-life of hydroxybupropion is approximately 20 (±5) hours and its AUC at steady state is about 17 times that of bupropion. The times to peak concentrations for the erythrohydrobupropion and threohydrobupropion metabolites are similar to that of the hydroxybupropion metabolite. However, their elimination half-lives are longer, 33(±10) and 37 (±13) hours, respectively, and steady-state AUCs are 1.5 and 7 times that of bupropion, respectively. •Absorption (Drug B): Can be systemically absorbed after skin application, being found in the deeper layers of the stratum corneum as well as urine, plasma, and breast milk. The mean maximum plasma concentration detected after application of 2mg/cm2 sunscreen was 7ng/mL in women and 16ng/mL in men. •Volume of distribution (Drug A): No volume of distribution available •Volume of distribution (Drug B): No volume of distribution available •Protein binding (Drug A): In vitro tests show that bupropion is 84% bound to human plasma proteins at concentrations up to 200 mcg per mL. The extent of protein binding of the hydroxybupropion metabolite is similar to that for bupropion, whereas the extent of protein binding of the threohydrobupropion metabolite is about half that seen with bupropion. •Metabolism (Drug A): Bupropion is extensively metabolized in humans. Three metabolites are active: hydroxybupropion, which is formed via hydroxylation of the tert-butyl group of bupropion, and the amino-alcohol isomers, threohydrobupropion and erythrohydrobupropion, which are formed via reduction of the carbonyl group. In vitro findings suggest that CYP2B6 is the principal isoenzyme involved in the formation of hydroxybupropion, while cytochrome P450 enzymes are not involved in the formation of threohydrobupropion. Hydroxybupropion has been shown to have the same affinity as bupropion for the norepinephrine transporter (NET) but approximately 50% of its antidepressant activity despite reaching concentrations of ~10-fold higher than that of the parent drug. Oxidation of the bupropion side chain results in the formation of a glycine conjugate of meta-chlorobenzoic acid, which is then excreted as the major urinary metabolite. The potency and toxicity of the metabolites relative to bupropion have not been fully characterized. However, it has been demonstrated in an antidepressant screening test in mice that hydroxybupropion is one-half as potent as bupropion, while threohydrobupropion and erythrohydrobupropion are 5-fold less potent than bupropion. This may be of clinical importance because the plasma concentrations of the metabolites are as high as or higher than those of bupropion. Bupropion and its metabolites exhibit linear kinetics following chronic administration of 300 to 450 mg per day. •Metabolism (Drug B): Can undergo hepatic metabolism when systematically absorbed. Can be enzymatically degraded by lipases in the stratum corneum where esters undergo hydrolysis. Degrade into photoproducts when exposed to sunlight, which leads to a decrease in UV absorption efficiency. •Route of elimination (Drug A): Bupropion is extensively metabolized in humans. Oxidation of the bupropion side chain results in the formation of a glycine conjugate of metachlorobenzoic acid, which is then excreted as the major urinary metabolite. Following oral administration of 200 mg of 14C-bupropion in humans, 87% and 10% of the radioactive dose were recovered in the urine and feces, respectively. However, the fraction of the oral dose of bupropion excreted unchanged was only 0.5%, a finding consistent with the extensive metabolism of bupropion. •Route of elimination (Drug B): Can be detected in urine in unchanged form. •Half-life (Drug A): 24 hours •Half-life (Drug B): No half-life available •Clearance (Drug A): No clearance available •Clearance (Drug B): No clearance available •Toxicity (Drug A): Symptoms of overdose include seizures, hallucinations, loss of consciousness, tachycardia, and cardiac arrest. •Toxicity (Drug B): Slightly hazardous in case of skin contact, eye contact, ingestion and inhalation. Octinoxate may form reactive singlet oxygen species and induce anti-estrogenic effects. UV-induced molecular breakdown of octinoxate may interfere with cellular processes or induce oxidative damage in human skin. The NOAEL (no observed adverse effect level) is 450 mg/kg bw/day for fertility and reproductive performance, for systemic parental and developmental toxicity in Wistar rats. •Brand Names (Drug A): Aplenzin, Auvelity, Budeprion, Contrave, Forfivo, Wellbutrin, Zyban •Brand Names (Drug B): Eucerin, Meijer, Sumadan Wash •Synonyms (Drug A): No synonyms listed •Synonyms (Drug B): No synonyms listed •Summary (Drug A): Bupropion is a norepinephrine and dopamine reuptake inhibitor used in the treatment of major depressive disorder (MDD), seasonal affective disorder (SAD), and as an aid to smoking cessation. •Summary (Drug B): Octinoxate is a sunscreen agent found in sunscreens that absorbs UV rays. Output: The renal excretion of drugs is the overall result of a combination of kidney processes that include glomerular filtration, passive diffusion, tubular secretion, and tubular reabsorption. Since two of these mechanisms - tubular secretion and reabsorption - are saturable processes , they are consequently susceptible to competition between multiple substrates excreted by the kidneys. If two or more medications that are mainly renally excreted are co-administered, they may compete for renal elimination; there is a large likelihood that one agent may "out-compete" or saturate the renal excretion mechanisms before the other concomitantly administered agent(s) are excreted. As a result, the elimination of these other concurrently administered agents may be inhibited or otherwise delayed, which could lead to increases in their serum concentrations and the risk, incidence, and/or severity of adverse effects associated with the exposure to such drugs. The severity of the interaction is minor.

Does Bupropion and Olanzapine interact?

•Drug A: Bupropion •Drug B: Olanzapine •Severity: MAJOR •Description: The metabolism of Olanzapine can be decreased when combined with Bupropion. •Extended Description: The subject drug is a strong CYP2D6 inhibitor and the affected drug is metabolized by CYP2D6. Concomitant administration may decrease the metabolism of the affected drug, which could increase serum concentrations as well as the risk and severity of adverse effects. •Indication (Drug A): Bupropion is indicated for the treatment of major depressive disorder (MDD), seasonal affective disorder (SAD), and as an aid to smoking cessation. When used in combination with naltrexone as the marketed product ContraveⓇ, bupropion is indicated as an adjunct to a reduced-calorie diet and increased physical activity for chronic weight management in adults with an initial body mass index (BMI) of: 30 kg/m^2 or greater (obese) or 27 kg/m^2 or greater (overweight) in the presence of at least one weight-related comorbid condition (e.g., hypertension, type 2 diabetes mellitus, or dyslipidemia). Bupropion is also used off-label as a first-line treatment in patients with ADHD and comorbid bipolar disorder when used as an adjunct to mood stabilizers. •Indication (Drug B): Olanzapine was initially used orally and intramuscularly for the chronic treatment of schizophrenia in patients over 13 years old and other psychiatric disorders such as bipolar I disorder including mixed or manic episodes. Olanzapine is also indicated, in combination with lithium or valproate for the short-term treatment of acute manic or mixed episodes associated with bipolar I disorder in adults. As well, olanzapine is indicated, in combination with fluoxetine for the treatment of episodes of depression associated with bipolar disorder type 1 and treatment-resistant depression in patients over 10 years old. Olanzapine is also approved for the management of psychomotor agitation associated with schizophrenia and bipolar I mania. Schizophrenia is a complex biochemical brain disorder that affects the person's ability to differentiate reality. It is usually observed as the presence of delusions, hallucinations, social withdrawal and disturbed thinking. Bipolar disorder is a mental health condition defined by periods of extreme mood disturbances. It is categorized in different types from which type 1 is known to involve episodes of severe mania and often depression while type 2 presents less severe forms of mania. Olanzapine is also indicated in combination with samidorphan for the treatment of bipolar I disorder, either as an adjunct to lithium or valproate or as monotherapy for the acute treatment of manic or mixed episodes or as maintenance therapy, and for the treatment of schizophrenia in adults. •Pharmacodynamics (Drug A): Bupropion is chemically unrelated to tricyclic, tetracyclic, selective serotonin re-uptake inhibitors, or other known antidepressant agents. Compared to classical tricyclic antidepressants, Bupropion is a relatively weak inhibitor of the neuronal uptake of norepinephrine and dopamine. In addition, Bupropion does not inhibit monoamine oxidase. Bupropion has been found to be essentially inactive at the serotonin transporter (SERT)(IC50 >10 000 nM), however both bupropion and its primary metabolite hydroxybupropion have been found to block the function of cation-selective serotonin type 3A receptors (5-HT3ARs). Bupropion produces dose-related central nervous system (CNS) stimulant effects in animals, as evidenced by increased locomotor activity, increased rates of responding in various schedule-controlled operant behaviour tasks, and, at high doses, induction of mild stereotyped behaviour. Due to these stimulant effects and selective activity at dopamine and norepinephrine receptors, bupropion has been identified as having an abuse potential. Bupropion has a similar structure to the controlled substance Cathinone, and has been identified as having mild amphetamine-like activity, particularly when inhaled or injected. Bupropion is also known to lower the seizure threshold, making any pre-existing seizure conditions a contraindication to its use. This risk is exacerbated when bupropion is combined with other drugs or substances that lower the seizure threshold, such as cocaine, or in clinical situations that would increase the risk of a seizure such as abrupt alcohol or benzodiazepine withdrawal. As norepinephrine has been shown to have anticonvulsant properties, bupropion's inhibitory effects on NET are thought to contribute to its pro-convulsant activity. Bupropion has been shown to increase blood pressure and pose a risk for exacerbation of unmanaged or pre-existing hypertension, however, clinical trials of bupropion in smokers with CVD have not identified an increased incidence of CV events including stroke or heart attack. In clinical trials, the mean increase in systolic blood pressure associated with the use of bupropion was found to be 1.3 mmHg. •Pharmacodynamics (Drug B): The effect of olanzapine in the D2 receptor is reported to produce the positive effects of this drug such as a decrease in hallucinations, delusions, disorganized speech, disorganized thought, and disorganized behavior. On the other hand, its effect on the serotonin 5HT2A receptor prevents the onset of anhedonia, flat affect, alogia, avolition and poor attention. Based on the specific mechanism of action, olanzapine presents a higher affinity for the dopamine D2 receptor when compared to the rest of the dopamine receptor isotypes. This characteristic significantly reduces the presence of side effects. Clinical trials for the original use of olanzapine demonstrated significant effectiveness in the treatment of schizophrenia and bipolar disorder in adults and acute manic or mixed episodes associated with bipolar disorder in adolescents. The effect of olanzapine on dopamine and serotonin receptors has been suggested to reduce chemotherapy-induced nausea and vomiting as those receptors are suggested to be involved in this process. For this effect, several clinical trials have been conducted and it has been shown that olanzapine can produce a significant increase in total control of nausea and vomiting. In a high-level study of the effect of olanzapine for this condition, a complete response on the delay phase was observed in 84% of the individual and control of emesis of over 80% despite the phase. •Mechanism of action (Drug A): Bupropion is a norepinephrine/dopamine-reuptake inhibitor (NDRI) that exerts its pharmacological effects by weakly inhibiting the enzymes involved in the uptake of the neurotransmitters norepinephrine and dopamine from the synaptic cleft, therefore prolonging their duration of action within the neuronal synapse and the downstream effects of these neurotransmitters. More specifically, bupropion binds to the norepinephrine transporter (NET) and the dopamine transporter (DAT). Bupropion was originally classified as an "atypical" antidepressant because it does not exert the same effects as the classical antidepressants such as Monoamine Oxidase Inhibitors (MAOIs), Tricyclic Antidepressants (TCAs), or Selective Serotonin Reuptake Inhibitors (SSRIs). While it has comparable effectiveness to typical first-line options for the treatment of depression such as SSRIs, bupropion is a unique option for the treatment of MDD as it lacks any clinically relevant serotonergic effects, typical of other mood medications, or any effects on histamine or adrenaline receptors. Lack of activity at these receptors results in a more tolerable side effect profile; bupropion is less likely to cause sexual side effects, sedation, or weight gain as compared to SSRIs or TCAs, for example. When used as an aid to smoking cessation, bupropion is thought to confer its anti-craving and anti-withdrawal effects by inhibiting dopamine reuptake, which is thought to be involved in the reward pathways associated with nicotine, and through the antagonism of the nicotinic acetylcholinergic receptor (AChR), thereby blunting the effects of nicotine. Furthermore, the stimulatory effects produced by bupropion in the central nervous system are similar to nicotine's effects, making low doses of bupropion a suitable option as a nicotine substitute. When used in combination with naltrexone in the marketed product ContraveⓇ for chronic weight management, the two components are thought to have effects on areas of the brain involved in the regulation of food intake. This includes the hypothalamus, which is involved in appetite regulation, and the mesolimbic dopamine circuit, which is involved in reward pathways. Studies have shown that the combined activity of bupropion and naltrexone increase the firing rate of hypothalamic pro-opiomelanocortin (POMC) neurons and blockade of opioid receptor-mediated POMC auto-inhibition, which are associated with a reduction in food intake and increased energy expenditure. This combination was also found to reduce food intake when injected directly into the ventral tegmental area of the mesolimbic circuit in mice, which is an area associated with the regulation of reward pathways. •Mechanism of action (Drug B): The activity of olanzapine is achieved by the antagonism of multiple neuronal receptors including the dopamine receptor D1, D2, D3 and D4 in the brain, the serotonin receptors 5HT2A, 5HT2C, 5HT3 and 5HT6, the alpha-1 adrenergic receptor, the histamine receptor H1 and multiple muscarinic receptors. As abovementioned, olanzapine presents a wide profile of targets, however, its antagonistic effect towards the dopamine D2 receptor in the mesolimbic pathway is key as it blocks dopamine from having a potential action at the post-synaptic receptor. The binding of olanzapine to the dopamine D2 receptors is easily dissociable and hence, it allows for a certain degree of dopamine neurotransmission. On the other hand, olanzapine acts in the serotonin 5HT2A receptors in the frontal cortex in a similar manner than the reported on dopamine D2 receptors. This determined effect allows for a decrease in adverse effects. •Absorption (Drug A): Bupropion is currently available in 3 distinct, but bioequivalent formulations: immediate release (IR), sustained-release (SR), and extended-release (XL). Immediate Release Formulation In humans, following oral administration of bupropion hydrochloride tablets, peak plasma bupropion concentrations are usually achieved within 2 hours. IR formulations provide a short duration of action and are therefore generally dosed three times per day. Sustained Release Formulation In humans, following oral administration of bupropion hydrochloride sustained-release tablets (SR), peak plasma concentration (Cmax) of bupropion is usually achieved within 3 hours. SR formulations provide a 12-hour extended release of medication and are therefore generally dosed twice per day. Extended Release Formulation Following single oral administration of bupropion hydrochloride extended-release tablets (XL) to healthy volunteers, the median time to peak plasma concentrations for bupropion was approximately 5 hours. The presence of food did not affect the peak concentration or area under the curve of bupropion. XL formulations provide a 24-hour extended release of medication and are therefore generally dosed once per day/ In a trial comparing chronic dosing with bupropion hydrochloride extended-release tablets (SR) 150 mg twice daily to bupropion immediate-release formulation 100 mg 3 times daily, the steady state Cmax for bupropion after bupropion hydrochloride sustained-release tablets (SR) administration was approximately 85% of those achieved after bupropion immediate-release formulation administration. Exposure (AUC) to bupropion was equivalent for both formulations. Bioequivalence was also demonstrated for all three major active metabolites (i.e., hydroxybupropion, threohydrobupropion and erythrohydrobupropion) for both Cmax and AUC. Thus, at steady state, bupropion hydrochloride sustained-release tablets (SR) given twice daily, and the immediate-release formulation of bupropion given 3 times daily, are essentially bioequivalent for both bupropion and the 3 quantitatively important metabolites. Furthermore, in a study comparing 14-day dosing with bupropion hydrochloride extended-release tablets (XL), 300 mg once-daily to the immediate-release formulation of bupropion at 100 mg 3 times daily, equivalence was demonstrated for peak plasma concentration and area under the curve for bupropion and the three metabolites (hydroxybupropion, threohydrobupropion, and erythrohydrobupropion). Additionally, in a study comparing 14-day dosing with bupropion hydrochloride extended-release tablets (XL) 300 mg once daily to the sustained-release formulation of bupropion at 150 mg 2 times daily, equivalence was demonstrated for peak plasma concentration and area under the curve for bupropion and the three metabolites. Bupropion hydrochloride extended-release tablets (SR) can be taken with or without food. Bupropion Cmax and AUC were increased by 11% to 35% and 16% to 19%, respectively, when bupropion hydrochloride extended-release tablets (SR) was administered with food to healthy volunteers in three trials. The food effect is not considered clinically significant. Following a single-dose administration of bupropion hydrochloride extended-release tablets (SR) in humans, Cmax of bupropion's metabolite hydroxybupropion occurs approximately 6 hours post-dose and is approximately 10 times the peak level of the parent drug at steady state. The elimination half-life of hydroxybupropion is approximately 20 (±5) hours and its AUC at steady state is about 17 times that of bupropion. The times to peak concentrations for the erythrohydrobupropion and threohydrobupropion metabolites are similar to that of the hydroxybupropion metabolite. However, their elimination half-lives are longer, 33(±10) and 37 (±13) hours, respectively, and steady-state AUCs are 1.5 and 7 times that of bupropion, respectively. •Absorption (Drug B): Olanzapine presents a linear pharmacokinetic profile and, after daily administration, it reaches steady-state in about a week. Under the administration of a normal dosage of olanzapine, the steady-state plasma concentration does not seem to exceed 150 ng/ml with an AUC of 333 ng/h/ml. The absorption of olanzapine is not affected by the concomitant administration of food. The pharmacokinetic profile of olanzapine is characterized by reaching peak plasma concentration of 156.9 ng/ml approximately 6 hours after oral administration. •Volume of distribution (Drug A): No volume of distribution available •Volume of distribution (Drug B): The volume of distribution of olanzapine is reported to be of 1000 liters which indicate a large distribution throughout the body. •Protein binding (Drug A): In vitro tests show that bupropion is 84% bound to human plasma proteins at concentrations up to 200 mcg per mL. The extent of protein binding of the hydroxybupropion metabolite is similar to that for bupropion, whereas the extent of protein binding of the threohydrobupropion metabolite is about half that seen with bupropion. •Protein binding (Drug B): Olanzapine is largely bound to plasma proteins and hence, about 93% of the administered dose is bound. The main proteins for binding are albumin and alpha-1 acid glycoprotein. •Metabolism (Drug A): Bupropion is extensively metabolized in humans. Three metabolites are active: hydroxybupropion, which is formed via hydroxylation of the tert-butyl group of bupropion, and the amino-alcohol isomers, threohydrobupropion and erythrohydrobupropion, which are formed via reduction of the carbonyl group. In vitro findings suggest that CYP2B6 is the principal isoenzyme involved in the formation of hydroxybupropion, while cytochrome P450 enzymes are not involved in the formation of threohydrobupropion. Hydroxybupropion has been shown to have the same affinity as bupropion for the norepinephrine transporter (NET) but approximately 50% of its antidepressant activity despite reaching concentrations of ~10-fold higher than that of the parent drug. Oxidation of the bupropion side chain results in the formation of a glycine conjugate of meta-chlorobenzoic acid, which is then excreted as the major urinary metabolite. The potency and toxicity of the metabolites relative to bupropion have not been fully characterized. However, it has been demonstrated in an antidepressant screening test in mice that hydroxybupropion is one-half as potent as bupropion, while threohydrobupropion and erythrohydrobupropion are 5-fold less potent than bupropion. This may be of clinical importance because the plasma concentrations of the metabolites are as high as or higher than those of bupropion. Bupropion and its metabolites exhibit linear kinetics following chronic administration of 300 to 450 mg per day. •Metabolism (Drug B): Olanzapine is greatly metabolized in the liver, which represents around 40% of the administered dose, mainly by the activity of glucuronide enzymes and by the cytochrome P450 system. From the CYP system, the main metabolic enzymes are CYP1A2 and CYP2D6. As part of the phase I metabolism, the major circulating metabolites of olanzapine, accounting for approximate 50-60% of this phase, are the 10-N-glucuronide and the 4'-N-desmethyl olanzapine which are clinically inactive and formed by the activity of CYP1A2. On the other hand, CYP2D6 catalyzes the formation of 2-OH olanzapine and the flavin-containing monooxygenase (FMO3) is responsible for N-oxide olanzapine. On the phase II metabolism of olanzapine, UGT1A4 is the key player by generating direct conjugation forms of olanzapine. •Route of elimination (Drug A): Bupropion is extensively metabolized in humans. Oxidation of the bupropion side chain results in the formation of a glycine conjugate of metachlorobenzoic acid, which is then excreted as the major urinary metabolite. Following oral administration of 200 mg of 14C-bupropion in humans, 87% and 10% of the radioactive dose were recovered in the urine and feces, respectively. However, the fraction of the oral dose of bupropion excreted unchanged was only 0.5%, a finding consistent with the extensive metabolism of bupropion. •Route of elimination (Drug B): Olanzapine is mainly eliminated through metabolism and hence, only 7% of the eliminated drug can be found as the unchanged form. It is mainly excreted in the urine which represents around 53% of the excreted dose followed by the feces that represent about 30%. •Half-life (Drug A): 24 hours •Half-life (Drug B): Olanzapine presents a half-life ranging between 21 to 54 hours with an average half-life of 30 hours. •Clearance (Drug A): No clearance available •Clearance (Drug B): The mean clearance rate of olanzapine is of 29.4 L/hour however, some studies have reported an apparent clearance of 25 L/h. •Toxicity (Drug A): Symptoms of overdose include seizures, hallucinations, loss of consciousness, tachycardia, and cardiac arrest. •Toxicity (Drug B): The toxicity symptoms of olanzapine are known to include somnolence, mydriasis, blurred vision, respiratory depression, hypotension, extrapyramidal symptoms and anticholinergic effects. The overdosage effects in children are generally associated with more significant side effects. The maximum registered dosage of olanzapine in clinical trials was of 300 mg and it was reported to present drowsiness and slurred speech. However, on post-marketing surveillance, a wide range of symptoms have been presented including agitation, dysarthria, tachycardia, extrapyramidal symptoms, and reduced consciousness. One case of overdosage-driven death was reported after ingestion of 450 mg of olanzapine. In the cases of acute overdosage, the establishment of adequate oxygenation and ventilation, gastric lavage and administration of activated charcoal with a laxative is recommended. In carcinogenesis studies, olanzapine was showed to present an increase in the incidence of liver hemangiomas and hemangiosarcomas as well as mammary gland adenomas, and adenocarcinomas. On fertility studies, there was solely found impairment in male mating performance and delays in ovulation. There is no evidence of mutagenic, genotoxic potential not adverse events on fertility. •Brand Names (Drug A): Aplenzin, Auvelity, Budeprion, Contrave, Forfivo, Wellbutrin, Zyban •Brand Names (Drug B): Lybalvi, Olazax, Symbyax, Zalasta, Zypadhera, Zyprexa •Synonyms (Drug A): No synonyms listed •Synonyms (Drug B): Olanzapin Olanzapina Olanzapine Olanzapinum •Summary (Drug A): Bupropion is a norepinephrine and dopamine reuptake inhibitor used in the treatment of major depressive disorder (MDD), seasonal affective disorder (SAD), and as an aid to smoking cessation. •Summary (Drug B): Olanzapine is an antipsychotic drug used in the management of schizophrenia, bipolar 1 disorder, and agitation associated with these disorders.

The subject drug is a strong CYP2D6 inhibitor and the affected drug is metabolized by CYP2D6. Concomitant administration may decrease the metabolism of the affected drug, which could increase serum concentrations as well as the risk and severity of adverse effects. The severity of the interaction is major.

Question: Does Bupropion and Olanzapine interact? Information: •Drug A: Bupropion •Drug B: Olanzapine •Severity: MAJOR •Description: The metabolism of Olanzapine can be decreased when combined with Bupropion. •Extended Description: The subject drug is a strong CYP2D6 inhibitor and the affected drug is metabolized by CYP2D6. Concomitant administration may decrease the metabolism of the affected drug, which could increase serum concentrations as well as the risk and severity of adverse effects. •Indication (Drug A): Bupropion is indicated for the treatment of major depressive disorder (MDD), seasonal affective disorder (SAD), and as an aid to smoking cessation. When used in combination with naltrexone as the marketed product ContraveⓇ, bupropion is indicated as an adjunct to a reduced-calorie diet and increased physical activity for chronic weight management in adults with an initial body mass index (BMI) of: 30 kg/m^2 or greater (obese) or 27 kg/m^2 or greater (overweight) in the presence of at least one weight-related comorbid condition (e.g., hypertension, type 2 diabetes mellitus, or dyslipidemia). Bupropion is also used off-label as a first-line treatment in patients with ADHD and comorbid bipolar disorder when used as an adjunct to mood stabilizers. •Indication (Drug B): Olanzapine was initially used orally and intramuscularly for the chronic treatment of schizophrenia in patients over 13 years old and other psychiatric disorders such as bipolar I disorder including mixed or manic episodes. Olanzapine is also indicated, in combination with lithium or valproate for the short-term treatment of acute manic or mixed episodes associated with bipolar I disorder in adults. As well, olanzapine is indicated, in combination with fluoxetine for the treatment of episodes of depression associated with bipolar disorder type 1 and treatment-resistant depression in patients over 10 years old. Olanzapine is also approved for the management of psychomotor agitation associated with schizophrenia and bipolar I mania. Schizophrenia is a complex biochemical brain disorder that affects the person's ability to differentiate reality. It is usually observed as the presence of delusions, hallucinations, social withdrawal and disturbed thinking. Bipolar disorder is a mental health condition defined by periods of extreme mood disturbances. It is categorized in different types from which type 1 is known to involve episodes of severe mania and often depression while type 2 presents less severe forms of mania. Olanzapine is also indicated in combination with samidorphan for the treatment of bipolar I disorder, either as an adjunct to lithium or valproate or as monotherapy for the acute treatment of manic or mixed episodes or as maintenance therapy, and for the treatment of schizophrenia in adults. •Pharmacodynamics (Drug A): Bupropion is chemically unrelated to tricyclic, tetracyclic, selective serotonin re-uptake inhibitors, or other known antidepressant agents. Compared to classical tricyclic antidepressants, Bupropion is a relatively weak inhibitor of the neuronal uptake of norepinephrine and dopamine. In addition, Bupropion does not inhibit monoamine oxidase. Bupropion has been found to be essentially inactive at the serotonin transporter (SERT)(IC50 >10 000 nM), however both bupropion and its primary metabolite hydroxybupropion have been found to block the function of cation-selective serotonin type 3A receptors (5-HT3ARs). Bupropion produces dose-related central nervous system (CNS) stimulant effects in animals, as evidenced by increased locomotor activity, increased rates of responding in various schedule-controlled operant behaviour tasks, and, at high doses, induction of mild stereotyped behaviour. Due to these stimulant effects and selective activity at dopamine and norepinephrine receptors, bupropion has been identified as having an abuse potential. Bupropion has a similar structure to the controlled substance Cathinone, and has been identified as having mild amphetamine-like activity, particularly when inhaled or injected. Bupropion is also known to lower the seizure threshold, making any pre-existing seizure conditions a contraindication to its use. This risk is exacerbated when bupropion is combined with other drugs or substances that lower the seizure threshold, such as cocaine, or in clinical situations that would increase the risk of a seizure such as abrupt alcohol or benzodiazepine withdrawal. As norepinephrine has been shown to have anticonvulsant properties, bupropion's inhibitory effects on NET are thought to contribute to its pro-convulsant activity. Bupropion has been shown to increase blood pressure and pose a risk for exacerbation of unmanaged or pre-existing hypertension, however, clinical trials of bupropion in smokers with CVD have not identified an increased incidence of CV events including stroke or heart attack. In clinical trials, the mean increase in systolic blood pressure associated with the use of bupropion was found to be 1.3 mmHg. •Pharmacodynamics (Drug B): The effect of olanzapine in the D2 receptor is reported to produce the positive effects of this drug such as a decrease in hallucinations, delusions, disorganized speech, disorganized thought, and disorganized behavior. On the other hand, its effect on the serotonin 5HT2A receptor prevents the onset of anhedonia, flat affect, alogia, avolition and poor attention. Based on the specific mechanism of action, olanzapine presents a higher affinity for the dopamine D2 receptor when compared to the rest of the dopamine receptor isotypes. This characteristic significantly reduces the presence of side effects. Clinical trials for the original use of olanzapine demonstrated significant effectiveness in the treatment of schizophrenia and bipolar disorder in adults and acute manic or mixed episodes associated with bipolar disorder in adolescents. The effect of olanzapine on dopamine and serotonin receptors has been suggested to reduce chemotherapy-induced nausea and vomiting as those receptors are suggested to be involved in this process. For this effect, several clinical trials have been conducted and it has been shown that olanzapine can produce a significant increase in total control of nausea and vomiting. In a high-level study of the effect of olanzapine for this condition, a complete response on the delay phase was observed in 84% of the individual and control of emesis of over 80% despite the phase. •Mechanism of action (Drug A): Bupropion is a norepinephrine/dopamine-reuptake inhibitor (NDRI) that exerts its pharmacological effects by weakly inhibiting the enzymes involved in the uptake of the neurotransmitters norepinephrine and dopamine from the synaptic cleft, therefore prolonging their duration of action within the neuronal synapse and the downstream effects of these neurotransmitters. More specifically, bupropion binds to the norepinephrine transporter (NET) and the dopamine transporter (DAT). Bupropion was originally classified as an "atypical" antidepressant because it does not exert the same effects as the classical antidepressants such as Monoamine Oxidase Inhibitors (MAOIs), Tricyclic Antidepressants (TCAs), or Selective Serotonin Reuptake Inhibitors (SSRIs). While it has comparable effectiveness to typical first-line options for the treatment of depression such as SSRIs, bupropion is a unique option for the treatment of MDD as it lacks any clinically relevant serotonergic effects, typical of other mood medications, or any effects on histamine or adrenaline receptors. Lack of activity at these receptors results in a more tolerable side effect profile; bupropion is less likely to cause sexual side effects, sedation, or weight gain as compared to SSRIs or TCAs, for example. When used as an aid to smoking cessation, bupropion is thought to confer its anti-craving and anti-withdrawal effects by inhibiting dopamine reuptake, which is thought to be involved in the reward pathways associated with nicotine, and through the antagonism of the nicotinic acetylcholinergic receptor (AChR), thereby blunting the effects of nicotine. Furthermore, the stimulatory effects produced by bupropion in the central nervous system are similar to nicotine's effects, making low doses of bupropion a suitable option as a nicotine substitute. When used in combination with naltrexone in the marketed product ContraveⓇ for chronic weight management, the two components are thought to have effects on areas of the brain involved in the regulation of food intake. This includes the hypothalamus, which is involved in appetite regulation, and the mesolimbic dopamine circuit, which is involved in reward pathways. Studies have shown that the combined activity of bupropion and naltrexone increase the firing rate of hypothalamic pro-opiomelanocortin (POMC) neurons and blockade of opioid receptor-mediated POMC auto-inhibition, which are associated with a reduction in food intake and increased energy expenditure. This combination was also found to reduce food intake when injected directly into the ventral tegmental area of the mesolimbic circuit in mice, which is an area associated with the regulation of reward pathways. •Mechanism of action (Drug B): The activity of olanzapine is achieved by the antagonism of multiple neuronal receptors including the dopamine receptor D1, D2, D3 and D4 in the brain, the serotonin receptors 5HT2A, 5HT2C, 5HT3 and 5HT6, the alpha-1 adrenergic receptor, the histamine receptor H1 and multiple muscarinic receptors. As abovementioned, olanzapine presents a wide profile of targets, however, its antagonistic effect towards the dopamine D2 receptor in the mesolimbic pathway is key as it blocks dopamine from having a potential action at the post-synaptic receptor. The binding of olanzapine to the dopamine D2 receptors is easily dissociable and hence, it allows for a certain degree of dopamine neurotransmission. On the other hand, olanzapine acts in the serotonin 5HT2A receptors in the frontal cortex in a similar manner than the reported on dopamine D2 receptors. This determined effect allows for a decrease in adverse effects. •Absorption (Drug A): Bupropion is currently available in 3 distinct, but bioequivalent formulations: immediate release (IR), sustained-release (SR), and extended-release (XL). Immediate Release Formulation In humans, following oral administration of bupropion hydrochloride tablets, peak plasma bupropion concentrations are usually achieved within 2 hours. IR formulations provide a short duration of action and are therefore generally dosed three times per day. Sustained Release Formulation In humans, following oral administration of bupropion hydrochloride sustained-release tablets (SR), peak plasma concentration (Cmax) of bupropion is usually achieved within 3 hours. SR formulations provide a 12-hour extended release of medication and are therefore generally dosed twice per day. Extended Release Formulation Following single oral administration of bupropion hydrochloride extended-release tablets (XL) to healthy volunteers, the median time to peak plasma concentrations for bupropion was approximately 5 hours. The presence of food did not affect the peak concentration or area under the curve of bupropion. XL formulations provide a 24-hour extended release of medication and are therefore generally dosed once per day/ In a trial comparing chronic dosing with bupropion hydrochloride extended-release tablets (SR) 150 mg twice daily to bupropion immediate-release formulation 100 mg 3 times daily, the steady state Cmax for bupropion after bupropion hydrochloride sustained-release tablets (SR) administration was approximately 85% of those achieved after bupropion immediate-release formulation administration. Exposure (AUC) to bupropion was equivalent for both formulations. Bioequivalence was also demonstrated for all three major active metabolites (i.e., hydroxybupropion, threohydrobupropion and erythrohydrobupropion) for both Cmax and AUC. Thus, at steady state, bupropion hydrochloride sustained-release tablets (SR) given twice daily, and the immediate-release formulation of bupropion given 3 times daily, are essentially bioequivalent for both bupropion and the 3 quantitatively important metabolites. Furthermore, in a study comparing 14-day dosing with bupropion hydrochloride extended-release tablets (XL), 300 mg once-daily to the immediate-release formulation of bupropion at 100 mg 3 times daily, equivalence was demonstrated for peak plasma concentration and area under the curve for bupropion and the three metabolites (hydroxybupropion, threohydrobupropion, and erythrohydrobupropion). Additionally, in a study comparing 14-day dosing with bupropion hydrochloride extended-release tablets (XL) 300 mg once daily to the sustained-release formulation of bupropion at 150 mg 2 times daily, equivalence was demonstrated for peak plasma concentration and area under the curve for bupropion and the three metabolites. Bupropion hydrochloride extended-release tablets (SR) can be taken with or without food. Bupropion Cmax and AUC were increased by 11% to 35% and 16% to 19%, respectively, when bupropion hydrochloride extended-release tablets (SR) was administered with food to healthy volunteers in three trials. The food effect is not considered clinically significant. Following a single-dose administration of bupropion hydrochloride extended-release tablets (SR) in humans, Cmax of bupropion's metabolite hydroxybupropion occurs approximately 6 hours post-dose and is approximately 10 times the peak level of the parent drug at steady state. The elimination half-life of hydroxybupropion is approximately 20 (±5) hours and its AUC at steady state is about 17 times that of bupropion. The times to peak concentrations for the erythrohydrobupropion and threohydrobupropion metabolites are similar to that of the hydroxybupropion metabolite. However, their elimination half-lives are longer, 33(±10) and 37 (±13) hours, respectively, and steady-state AUCs are 1.5 and 7 times that of bupropion, respectively. •Absorption (Drug B): Olanzapine presents a linear pharmacokinetic profile and, after daily administration, it reaches steady-state in about a week. Under the administration of a normal dosage of olanzapine, the steady-state plasma concentration does not seem to exceed 150 ng/ml with an AUC of 333 ng/h/ml. The absorption of olanzapine is not affected by the concomitant administration of food. The pharmacokinetic profile of olanzapine is characterized by reaching peak plasma concentration of 156.9 ng/ml approximately 6 hours after oral administration. •Volume of distribution (Drug A): No volume of distribution available •Volume of distribution (Drug B): The volume of distribution of olanzapine is reported to be of 1000 liters which indicate a large distribution throughout the body. •Protein binding (Drug A): In vitro tests show that bupropion is 84% bound to human plasma proteins at concentrations up to 200 mcg per mL. The extent of protein binding of the hydroxybupropion metabolite is similar to that for bupropion, whereas the extent of protein binding of the threohydrobupropion metabolite is about half that seen with bupropion. •Protein binding (Drug B): Olanzapine is largely bound to plasma proteins and hence, about 93% of the administered dose is bound. The main proteins for binding are albumin and alpha-1 acid glycoprotein. •Metabolism (Drug A): Bupropion is extensively metabolized in humans. Three metabolites are active: hydroxybupropion, which is formed via hydroxylation of the tert-butyl group of bupropion, and the amino-alcohol isomers, threohydrobupropion and erythrohydrobupropion, which are formed via reduction of the carbonyl group. In vitro findings suggest that CYP2B6 is the principal isoenzyme involved in the formation of hydroxybupropion, while cytochrome P450 enzymes are not involved in the formation of threohydrobupropion. Hydroxybupropion has been shown to have the same affinity as bupropion for the norepinephrine transporter (NET) but approximately 50% of its antidepressant activity despite reaching concentrations of ~10-fold higher than that of the parent drug. Oxidation of the bupropion side chain results in the formation of a glycine conjugate of meta-chlorobenzoic acid, which is then excreted as the major urinary metabolite. The potency and toxicity of the metabolites relative to bupropion have not been fully characterized. However, it has been demonstrated in an antidepressant screening test in mice that hydroxybupropion is one-half as potent as bupropion, while threohydrobupropion and erythrohydrobupropion are 5-fold less potent than bupropion. This may be of clinical importance because the plasma concentrations of the metabolites are as high as or higher than those of bupropion. Bupropion and its metabolites exhibit linear kinetics following chronic administration of 300 to 450 mg per day. •Metabolism (Drug B): Olanzapine is greatly metabolized in the liver, which represents around 40% of the administered dose, mainly by the activity of glucuronide enzymes and by the cytochrome P450 system. From the CYP system, the main metabolic enzymes are CYP1A2 and CYP2D6. As part of the phase I metabolism, the major circulating metabolites of olanzapine, accounting for approximate 50-60% of this phase, are the 10-N-glucuronide and the 4'-N-desmethyl olanzapine which are clinically inactive and formed by the activity of CYP1A2. On the other hand, CYP2D6 catalyzes the formation of 2-OH olanzapine and the flavin-containing monooxygenase (FMO3) is responsible for N-oxide olanzapine. On the phase II metabolism of olanzapine, UGT1A4 is the key player by generating direct conjugation forms of olanzapine. •Route of elimination (Drug A): Bupropion is extensively metabolized in humans. Oxidation of the bupropion side chain results in the formation of a glycine conjugate of metachlorobenzoic acid, which is then excreted as the major urinary metabolite. Following oral administration of 200 mg of 14C-bupropion in humans, 87% and 10% of the radioactive dose were recovered in the urine and feces, respectively. However, the fraction of the oral dose of bupropion excreted unchanged was only 0.5%, a finding consistent with the extensive metabolism of bupropion. •Route of elimination (Drug B): Olanzapine is mainly eliminated through metabolism and hence, only 7% of the eliminated drug can be found as the unchanged form. It is mainly excreted in the urine which represents around 53% of the excreted dose followed by the feces that represent about 30%. •Half-life (Drug A): 24 hours •Half-life (Drug B): Olanzapine presents a half-life ranging between 21 to 54 hours with an average half-life of 30 hours. •Clearance (Drug A): No clearance available •Clearance (Drug B): The mean clearance rate of olanzapine is of 29.4 L/hour however, some studies have reported an apparent clearance of 25 L/h. •Toxicity (Drug A): Symptoms of overdose include seizures, hallucinations, loss of consciousness, tachycardia, and cardiac arrest. •Toxicity (Drug B): The toxicity symptoms of olanzapine are known to include somnolence, mydriasis, blurred vision, respiratory depression, hypotension, extrapyramidal symptoms and anticholinergic effects. The overdosage effects in children are generally associated with more significant side effects. The maximum registered dosage of olanzapine in clinical trials was of 300 mg and it was reported to present drowsiness and slurred speech. However, on post-marketing surveillance, a wide range of symptoms have been presented including agitation, dysarthria, tachycardia, extrapyramidal symptoms, and reduced consciousness. One case of overdosage-driven death was reported after ingestion of 450 mg of olanzapine. In the cases of acute overdosage, the establishment of adequate oxygenation and ventilation, gastric lavage and administration of activated charcoal with a laxative is recommended. In carcinogenesis studies, olanzapine was showed to present an increase in the incidence of liver hemangiomas and hemangiosarcomas as well as mammary gland adenomas, and adenocarcinomas. On fertility studies, there was solely found impairment in male mating performance and delays in ovulation. There is no evidence of mutagenic, genotoxic potential not adverse events on fertility. •Brand Names (Drug A): Aplenzin, Auvelity, Budeprion, Contrave, Forfivo, Wellbutrin, Zyban •Brand Names (Drug B): Lybalvi, Olazax, Symbyax, Zalasta, Zypadhera, Zyprexa •Synonyms (Drug A): No synonyms listed •Synonyms (Drug B): Olanzapin Olanzapina Olanzapine Olanzapinum •Summary (Drug A): Bupropion is a norepinephrine and dopamine reuptake inhibitor used in the treatment of major depressive disorder (MDD), seasonal affective disorder (SAD), and as an aid to smoking cessation. •Summary (Drug B): Olanzapine is an antipsychotic drug used in the management of schizophrenia, bipolar 1 disorder, and agitation associated with these disorders. Output: The subject drug is a strong CYP2D6 inhibitor and the affected drug is metabolized by CYP2D6. Concomitant administration may decrease the metabolism of the affected drug, which could increase serum concentrations as well as the risk and severity of adverse effects. The severity of the interaction is major.

Does Bupropion and Oliceridine interact?

•Drug A: Bupropion •Drug B: Oliceridine •Severity: MAJOR •Description: The risk or severity of hypotension, sedation, death, somnolence, and respiratory depression can be increased when Bupropion is combined with Oliceridine. •Extended Description: Oliceridine displays an additive pharmacologic effect with CNS depressants such as benzodiazepines and alcohol, which increases the risk of hypotension, respiratory depression, sedation, coma, and death. •Indication (Drug A): Bupropion is indicated for the treatment of major depressive disorder (MDD), seasonal affective disorder (SAD), and as an aid to smoking cessation. When used in combination with naltrexone as the marketed product ContraveⓇ, bupropion is indicated as an adjunct to a reduced-calorie diet and increased physical activity for chronic weight management in adults with an initial body mass index (BMI) of: 30 kg/m^2 or greater (obese) or 27 kg/m^2 or greater (overweight) in the presence of at least one weight-related comorbid condition (e.g., hypertension, type 2 diabetes mellitus, or dyslipidemia). Bupropion is also used off-label as a first-line treatment in patients with ADHD and comorbid bipolar disorder when used as an adjunct to mood stabilizers. •Indication (Drug B): Oliceridine is indicated for the management of acute pain in adults severe enough to require intravenous opioid analgesics and for whom no acceptable alternative treatments exist. •Pharmacodynamics (Drug A): Bupropion is chemically unrelated to tricyclic, tetracyclic, selective serotonin re-uptake inhibitors, or other known antidepressant agents. Compared to classical tricyclic antidepressants, Bupropion is a relatively weak inhibitor of the neuronal uptake of norepinephrine and dopamine. In addition, Bupropion does not inhibit monoamine oxidase. Bupropion has been found to be essentially inactive at the serotonin transporter (SERT)(IC50 >10 000 nM), however both bupropion and its primary metabolite hydroxybupropion have been found to block the function of cation-selective serotonin type 3A receptors (5-HT3ARs). Bupropion produces dose-related central nervous system (CNS) stimulant effects in animals, as evidenced by increased locomotor activity, increased rates of responding in various schedule-controlled operant behaviour tasks, and, at high doses, induction of mild stereotyped behaviour. Due to these stimulant effects and selective activity at dopamine and norepinephrine receptors, bupropion has been identified as having an abuse potential. Bupropion has a similar structure to the controlled substance Cathinone, and has been identified as having mild amphetamine-like activity, particularly when inhaled or injected. Bupropion is also known to lower the seizure threshold, making any pre-existing seizure conditions a contraindication to its use. This risk is exacerbated when bupropion is combined with other drugs or substances that lower the seizure threshold, such as cocaine, or in clinical situations that would increase the risk of a seizure such as abrupt alcohol or benzodiazepine withdrawal. As norepinephrine has been shown to have anticonvulsant properties, bupropion's inhibitory effects on NET are thought to contribute to its pro-convulsant activity. Bupropion has been shown to increase blood pressure and pose a risk for exacerbation of unmanaged or pre-existing hypertension, however, clinical trials of bupropion in smokers with CVD have not identified an increased incidence of CV events including stroke or heart attack. In clinical trials, the mean increase in systolic blood pressure associated with the use of bupropion was found to be 1.3 mmHg. •Pharmacodynamics (Drug B): Oliceridine is a biased μ-opioid receptor agonist that acts through downstream signalling pathways to exert antinociceptive analgesia in patients experience severe acute pain. Results from multiple clinical studies and simulation data demonstrate that oliceridine exerts significant analgesic benefits within 5-20 minutes following administration but dissipates quickly with a half-life between one and three hours. Despite an improved adverse effect profile over conventional opioids, oliceridine carries important clinical warnings. Oliceridine has the potential to cause severe respiratory depression, especially in patients who are elderly, cachectic, debilitated, or who otherwise have chronically impaired pulmonary function. In addition, severe respiratory depression or sedation may occur in patients with increased intracranial pressure, head injury, brain tumour, or impaired consciousness. Patients with adrenal insufficiency or severe hypotension may require treatment alterations or discontinuation. Finally, oliceridine has been demonstrated to prolong the QTc interval and has not been properly evaluated beyond a maximum daily dose of 27 mg; it is recommended not to exceed 27 mg per day. •Mechanism of action (Drug A): Bupropion is a norepinephrine/dopamine-reuptake inhibitor (NDRI) that exerts its pharmacological effects by weakly inhibiting the enzymes involved in the uptake of the neurotransmitters norepinephrine and dopamine from the synaptic cleft, therefore prolonging their duration of action within the neuronal synapse and the downstream effects of these neurotransmitters. More specifically, bupropion binds to the norepinephrine transporter (NET) and the dopamine transporter (DAT). Bupropion was originally classified as an "atypical" antidepressant because it does not exert the same effects as the classical antidepressants such as Monoamine Oxidase Inhibitors (MAOIs), Tricyclic Antidepressants (TCAs), or Selective Serotonin Reuptake Inhibitors (SSRIs). While it has comparable effectiveness to typical first-line options for the treatment of depression such as SSRIs, bupropion is a unique option for the treatment of MDD as it lacks any clinically relevant serotonergic effects, typical of other mood medications, or any effects on histamine or adrenaline receptors. Lack of activity at these receptors results in a more tolerable side effect profile; bupropion is less likely to cause sexual side effects, sedation, or weight gain as compared to SSRIs or TCAs, for example. When used as an aid to smoking cessation, bupropion is thought to confer its anti-craving and anti-withdrawal effects by inhibiting dopamine reuptake, which is thought to be involved in the reward pathways associated with nicotine, and through the antagonism of the nicotinic acetylcholinergic receptor (AChR), thereby blunting the effects of nicotine. Furthermore, the stimulatory effects produced by bupropion in the central nervous system are similar to nicotine's effects, making low doses of bupropion a suitable option as a nicotine substitute. When used in combination with naltrexone in the marketed product ContraveⓇ for chronic weight management, the two components are thought to have effects on areas of the brain involved in the regulation of food intake. This includes the hypothalamus, which is involved in appetite regulation, and the mesolimbic dopamine circuit, which is involved in reward pathways. Studies have shown that the combined activity of bupropion and naltrexone increase the firing rate of hypothalamic pro-opiomelanocortin (POMC) neurons and blockade of opioid receptor-mediated POMC auto-inhibition, which are associated with a reduction in food intake and increased energy expenditure. This combination was also found to reduce food intake when injected directly into the ventral tegmental area of the mesolimbic circuit in mice, which is an area associated with the regulation of reward pathways. •Mechanism of action (Drug B): Pain perception follows a complex pathway initiated in primary sensory neurons, subsequently transmitted to the spinal cord dorsal horn and through ascending axons to multiple regions within the thalamus, brainstem, and midbrain, and finally relayed through descending signals that either inhibit or facilitate the nociceptive signalling. Opioid receptors are seven-transmembrane G-protein-coupled receptors (GPCRs) that can be divided into μ, κ, δ, and opioid-like-1 (ORL1) subtypes,. However, the μ-opioid receptor is predominantly targeted by and is responsible for the effects of traditional opioids. GPCRs in the inactive state are bound intracellularly by a complex consisting of a G α, β, and γ subunit together with guanosine diphosphate (GDP). Activation of the GPCR through extracellular agonist binding catalyzes the replacement of GDP with guanosine triphosphate (GTP), dissociation of both G α -GTP and a βγ heterodimer, and subsequent downstream effects. In the case of the μ-opioid receptor, the G α -GTP directly interacts with the potassium channel K ir 3 while the dissociated Gβγ subunit directly binds to and occludes the pore of P/Q-, N-, and L-type Ca channels. Furthermore, opioid receptor activation inhibits adenylyl cyclase, which in turn reduces cAMP-dependent Ca influx. By altering membrane ion conductivity, these effects modulate nociceptive signalling and produce an analgesic effect. In addition to the G-protein pathway, μ-opioid receptor activation can also result in downstream signalling through β-arrestin, which results in receptor internalization and is associated with negative effects of opioid use including respiratory depression, gastrointestinal effects, and desensitization/tolerance. Oliceridine acts as a "biased agonist" at the μ-opioid receptor by preferentially activating the G-protein pathway with minimal receptor phosphorylation and recruitment of β-arrestin. Competetive binding assays and structural modelling suggest that the binding site for oliceridine on the μ-opioid receptor is the same as for classical opioids. However, molecular modelling supports a model whereby oliceridine binding induces a different intracellular conformation of the μ-opioid receptor, specifically due to a lack of coupling with transmembrane helix six, which confers the specificity for G-protein over β-arrestin interaction. Numerous in vitro, in vivo, and clinical studies support the view that this biased agonism results in comparable analgesia compared with traditional opioids at a comparable or decreased risk of opioid-related adverse effects such as constipation and respiratory depression. •Absorption (Drug A): Bupropion is currently available in 3 distinct, but bioequivalent formulations: immediate release (IR), sustained-release (SR), and extended-release (XL). Immediate Release Formulation In humans, following oral administration of bupropion hydrochloride tablets, peak plasma bupropion concentrations are usually achieved within 2 hours. IR formulations provide a short duration of action and are therefore generally dosed three times per day. Sustained Release Formulation In humans, following oral administration of bupropion hydrochloride sustained-release tablets (SR), peak plasma concentration (Cmax) of bupropion is usually achieved within 3 hours. SR formulations provide a 12-hour extended release of medication and are therefore generally dosed twice per day. Extended Release Formulation Following single oral administration of bupropion hydrochloride extended-release tablets (XL) to healthy volunteers, the median time to peak plasma concentrations for bupropion was approximately 5 hours. The presence of food did not affect the peak concentration or area under the curve of bupropion. XL formulations provide a 24-hour extended release of medication and are therefore generally dosed once per day/ In a trial comparing chronic dosing with bupropion hydrochloride extended-release tablets (SR) 150 mg twice daily to bupropion immediate-release formulation 100 mg 3 times daily, the steady state Cmax for bupropion after bupropion hydrochloride sustained-release tablets (SR) administration was approximately 85% of those achieved after bupropion immediate-release formulation administration. Exposure (AUC) to bupropion was equivalent for both formulations. Bioequivalence was also demonstrated for all three major active metabolites (i.e., hydroxybupropion, threohydrobupropion and erythrohydrobupropion) for both Cmax and AUC. Thus, at steady state, bupropion hydrochloride sustained-release tablets (SR) given twice daily, and the immediate-release formulation of bupropion given 3 times daily, are essentially bioequivalent for both bupropion and the 3 quantitatively important metabolites. Furthermore, in a study comparing 14-day dosing with bupropion hydrochloride extended-release tablets (XL), 300 mg once-daily to the immediate-release formulation of bupropion at 100 mg 3 times daily, equivalence was demonstrated for peak plasma concentration and area under the curve for bupropion and the three metabolites (hydroxybupropion, threohydrobupropion, and erythrohydrobupropion). Additionally, in a study comparing 14-day dosing with bupropion hydrochloride extended-release tablets (XL) 300 mg once daily to the sustained-release formulation of bupropion at 150 mg 2 times daily, equivalence was demonstrated for peak plasma concentration and area under the curve for bupropion and the three metabolites. Bupropion hydrochloride extended-release tablets (SR) can be taken with or without food. Bupropion Cmax and AUC were increased by 11% to 35% and 16% to 19%, respectively, when bupropion hydrochloride extended-release tablets (SR) was administered with food to healthy volunteers in three trials. The food effect is not considered clinically significant. Following a single-dose administration of bupropion hydrochloride extended-release tablets (SR) in humans, Cmax of bupropion's metabolite hydroxybupropion occurs approximately 6 hours post-dose and is approximately 10 times the peak level of the parent drug at steady state. The elimination half-life of hydroxybupropion is approximately 20 (±5) hours and its AUC at steady state is about 17 times that of bupropion. The times to peak concentrations for the erythrohydrobupropion and threohydrobupropion metabolites are similar to that of the hydroxybupropion metabolite. However, their elimination half-lives are longer, 33(±10) and 37 (±13) hours, respectively, and steady-state AUCs are 1.5 and 7 times that of bupropion, respectively. •Absorption (Drug B): Oliceridine administered as a single intravenous injection of 1.5, 3, or 4.5 mg in healthy male volunteers had a corresponding C max of 47, 76, and 119 ng/mL and a corresponding AUC 0-24 of 43, 82, and 122 ng*h/mL. Simulations of single doses of oliceridine between 1-3 mg suggest that the expected median C max is between 43 and 130 ng/mL while the expected median AUC is between 22 and 70 ng*h/mL. •Volume of distribution (Drug A): No volume of distribution available •Volume of distribution (Drug B): Oliceridine has a mean steady-state volume of distribution of 90-120 L. •Protein binding (Drug A): In vitro tests show that bupropion is 84% bound to human plasma proteins at concentrations up to 200 mcg per mL. The extent of protein binding of the hydroxybupropion metabolite is similar to that for bupropion, whereas the extent of protein binding of the threohydrobupropion metabolite is about half that seen with bupropion. •Protein binding (Drug B): Oliceridine is approximately 77% bound to plasma proteins. •Metabolism (Drug A): Bupropion is extensively metabolized in humans. Three metabolites are active: hydroxybupropion, which is formed via hydroxylation of the tert-butyl group of bupropion, and the amino-alcohol isomers, threohydrobupropion and erythrohydrobupropion, which are formed via reduction of the carbonyl group. In vitro findings suggest that CYP2B6 is the principal isoenzyme involved in the formation of hydroxybupropion, while cytochrome P450 enzymes are not involved in the formation of threohydrobupropion. Hydroxybupropion has been shown to have the same affinity as bupropion for the norepinephrine transporter (NET) but approximately 50% of its antidepressant activity despite reaching concentrations of ~10-fold higher than that of the parent drug. Oxidation of the bupropion side chain results in the formation of a glycine conjugate of meta-chlorobenzoic acid, which is then excreted as the major urinary metabolite. The potency and toxicity of the metabolites relative to bupropion have not been fully characterized. However, it has been demonstrated in an antidepressant screening test in mice that hydroxybupropion is one-half as potent as bupropion, while threohydrobupropion and erythrohydrobupropion are 5-fold less potent than bupropion. This may be of clinical importance because the plasma concentrations of the metabolites are as high as or higher than those of bupropion. Bupropion and its metabolites exhibit linear kinetics following chronic administration of 300 to 450 mg per day. •Metabolism (Drug B): Oliceridine is primarily metabolized hepatically by CYP3A4 and CYP2D6 in vitro, with minor contributions from CYP2C9 and CYP2C19. None of oliceridine's metabolites are known to be active. Metabolic pathways include N-dealkylation, glucuronidation, and dehydrogenation. •Route of elimination (Drug A): Bupropion is extensively metabolized in humans. Oxidation of the bupropion side chain results in the formation of a glycine conjugate of metachlorobenzoic acid, which is then excreted as the major urinary metabolite. Following oral administration of 200 mg of 14C-bupropion in humans, 87% and 10% of the radioactive dose were recovered in the urine and feces, respectively. However, the fraction of the oral dose of bupropion excreted unchanged was only 0.5%, a finding consistent with the extensive metabolism of bupropion. •Route of elimination (Drug B): Approximately 70% of oliceridine is eliminated via the renal route, of which only 0.97-6.75% of an initial dose is recovered unchanged. The remaining 30% is eliminated in feces. •Half-life (Drug A): 24 hours •Half-life (Drug B): Oliceridine has a half-life of 1.3-3 hours while its metabolites, none of which are known to be active, have a substantially longer half-life of 44 hours. •Clearance (Drug A): No clearance available •Clearance (Drug B): Healthy volunteers given doses of oliceridine between 0.15 and 7 mg had mean clearance rates between 34 and 59.6 L/h. •Toxicity (Drug A): Symptoms of overdose include seizures, hallucinations, loss of consciousness, tachycardia, and cardiac arrest. •Toxicity (Drug B): Symptoms of oliceridine overdose are variable but can include respiratory depression, airway obstruction, pulmonary edema, bradycardia, hypotension, muscle flaccidity, cold skin, and somnolence progressing to either stupor or coma. Miosis is commonly observed but in cases of severe hypoxia, mydriasis may be observed instead. Oliceridine overdose may be fatal. In case of overdose, the establishment of a protected airway followed by the institution of assisted or controlled ventilation is a high priority; in case of cardiac arrhythmias or arrest, additional supportive measures may be immediately required. Supportive treatment, including oxygen, vasopressors, and the administration of an opioid antagonist such as naloxone may be applied but should be tailored to the individual patient's condition. •Brand Names (Drug A): Aplenzin, Auvelity, Budeprion, Contrave, Forfivo, Wellbutrin, Zyban •Brand Names (Drug B): Olinvyk •Synonyms (Drug A): No synonyms listed •Synonyms (Drug B): No synonyms listed •Summary (Drug A): Bupropion is a norepinephrine and dopamine reuptake inhibitor used in the treatment of major depressive disorder (MDD), seasonal affective disorder (SAD), and as an aid to smoking cessation. •Summary (Drug B): Oliceridine is a biased opioid agonist indicated for the management of severe acute pain in adult patients. Through preferential activation of G-protein-coupled signalling pathways, oliceridine provides analgesic effect with a comparable or improved safety profile over conventional opioid agonists.

Oliceridine displays an additive pharmacologic effect with CNS depressants such as benzodiazepines and alcohol, which increases the risk of hypotension, respiratory depression, sedation, coma, and death. The severity of the interaction is major.

Question: Does Bupropion and Oliceridine interact? Information: •Drug A: Bupropion •Drug B: Oliceridine •Severity: MAJOR •Description: The risk or severity of hypotension, sedation, death, somnolence, and respiratory depression can be increased when Bupropion is combined with Oliceridine. •Extended Description: Oliceridine displays an additive pharmacologic effect with CNS depressants such as benzodiazepines and alcohol, which increases the risk of hypotension, respiratory depression, sedation, coma, and death. •Indication (Drug A): Bupropion is indicated for the treatment of major depressive disorder (MDD), seasonal affective disorder (SAD), and as an aid to smoking cessation. When used in combination with naltrexone as the marketed product ContraveⓇ, bupropion is indicated as an adjunct to a reduced-calorie diet and increased physical activity for chronic weight management in adults with an initial body mass index (BMI) of: 30 kg/m^2 or greater (obese) or 27 kg/m^2 or greater (overweight) in the presence of at least one weight-related comorbid condition (e.g., hypertension, type 2 diabetes mellitus, or dyslipidemia). Bupropion is also used off-label as a first-line treatment in patients with ADHD and comorbid bipolar disorder when used as an adjunct to mood stabilizers. •Indication (Drug B): Oliceridine is indicated for the management of acute pain in adults severe enough to require intravenous opioid analgesics and for whom no acceptable alternative treatments exist. •Pharmacodynamics (Drug A): Bupropion is chemically unrelated to tricyclic, tetracyclic, selective serotonin re-uptake inhibitors, or other known antidepressant agents. Compared to classical tricyclic antidepressants, Bupropion is a relatively weak inhibitor of the neuronal uptake of norepinephrine and dopamine. In addition, Bupropion does not inhibit monoamine oxidase. Bupropion has been found to be essentially inactive at the serotonin transporter (SERT)(IC50 >10 000 nM), however both bupropion and its primary metabolite hydroxybupropion have been found to block the function of cation-selective serotonin type 3A receptors (5-HT3ARs). Bupropion produces dose-related central nervous system (CNS) stimulant effects in animals, as evidenced by increased locomotor activity, increased rates of responding in various schedule-controlled operant behaviour tasks, and, at high doses, induction of mild stereotyped behaviour. Due to these stimulant effects and selective activity at dopamine and norepinephrine receptors, bupropion has been identified as having an abuse potential. Bupropion has a similar structure to the controlled substance Cathinone, and has been identified as having mild amphetamine-like activity, particularly when inhaled or injected. Bupropion is also known to lower the seizure threshold, making any pre-existing seizure conditions a contraindication to its use. This risk is exacerbated when bupropion is combined with other drugs or substances that lower the seizure threshold, such as cocaine, or in clinical situations that would increase the risk of a seizure such as abrupt alcohol or benzodiazepine withdrawal. As norepinephrine has been shown to have anticonvulsant properties, bupropion's inhibitory effects on NET are thought to contribute to its pro-convulsant activity. Bupropion has been shown to increase blood pressure and pose a risk for exacerbation of unmanaged or pre-existing hypertension, however, clinical trials of bupropion in smokers with CVD have not identified an increased incidence of CV events including stroke or heart attack. In clinical trials, the mean increase in systolic blood pressure associated with the use of bupropion was found to be 1.3 mmHg. •Pharmacodynamics (Drug B): Oliceridine is a biased μ-opioid receptor agonist that acts through downstream signalling pathways to exert antinociceptive analgesia in patients experience severe acute pain. Results from multiple clinical studies and simulation data demonstrate that oliceridine exerts significant analgesic benefits within 5-20 minutes following administration but dissipates quickly with a half-life between one and three hours. Despite an improved adverse effect profile over conventional opioids, oliceridine carries important clinical warnings. Oliceridine has the potential to cause severe respiratory depression, especially in patients who are elderly, cachectic, debilitated, or who otherwise have chronically impaired pulmonary function. In addition, severe respiratory depression or sedation may occur in patients with increased intracranial pressure, head injury, brain tumour, or impaired consciousness. Patients with adrenal insufficiency or severe hypotension may require treatment alterations or discontinuation. Finally, oliceridine has been demonstrated to prolong the QTc interval and has not been properly evaluated beyond a maximum daily dose of 27 mg; it is recommended not to exceed 27 mg per day. •Mechanism of action (Drug A): Bupropion is a norepinephrine/dopamine-reuptake inhibitor (NDRI) that exerts its pharmacological effects by weakly inhibiting the enzymes involved in the uptake of the neurotransmitters norepinephrine and dopamine from the synaptic cleft, therefore prolonging their duration of action within the neuronal synapse and the downstream effects of these neurotransmitters. More specifically, bupropion binds to the norepinephrine transporter (NET) and the dopamine transporter (DAT). Bupropion was originally classified as an "atypical" antidepressant because it does not exert the same effects as the classical antidepressants such as Monoamine Oxidase Inhibitors (MAOIs), Tricyclic Antidepressants (TCAs), or Selective Serotonin Reuptake Inhibitors (SSRIs). While it has comparable effectiveness to typical first-line options for the treatment of depression such as SSRIs, bupropion is a unique option for the treatment of MDD as it lacks any clinically relevant serotonergic effects, typical of other mood medications, or any effects on histamine or adrenaline receptors. Lack of activity at these receptors results in a more tolerable side effect profile; bupropion is less likely to cause sexual side effects, sedation, or weight gain as compared to SSRIs or TCAs, for example. When used as an aid to smoking cessation, bupropion is thought to confer its anti-craving and anti-withdrawal effects by inhibiting dopamine reuptake, which is thought to be involved in the reward pathways associated with nicotine, and through the antagonism of the nicotinic acetylcholinergic receptor (AChR), thereby blunting the effects of nicotine. Furthermore, the stimulatory effects produced by bupropion in the central nervous system are similar to nicotine's effects, making low doses of bupropion a suitable option as a nicotine substitute. When used in combination with naltrexone in the marketed product ContraveⓇ for chronic weight management, the two components are thought to have effects on areas of the brain involved in the regulation of food intake. This includes the hypothalamus, which is involved in appetite regulation, and the mesolimbic dopamine circuit, which is involved in reward pathways. Studies have shown that the combined activity of bupropion and naltrexone increase the firing rate of hypothalamic pro-opiomelanocortin (POMC) neurons and blockade of opioid receptor-mediated POMC auto-inhibition, which are associated with a reduction in food intake and increased energy expenditure. This combination was also found to reduce food intake when injected directly into the ventral tegmental area of the mesolimbic circuit in mice, which is an area associated with the regulation of reward pathways. •Mechanism of action (Drug B): Pain perception follows a complex pathway initiated in primary sensory neurons, subsequently transmitted to the spinal cord dorsal horn and through ascending axons to multiple regions within the thalamus, brainstem, and midbrain, and finally relayed through descending signals that either inhibit or facilitate the nociceptive signalling. Opioid receptors are seven-transmembrane G-protein-coupled receptors (GPCRs) that can be divided into μ, κ, δ, and opioid-like-1 (ORL1) subtypes,. However, the μ-opioid receptor is predominantly targeted by and is responsible for the effects of traditional opioids. GPCRs in the inactive state are bound intracellularly by a complex consisting of a G α, β, and γ subunit together with guanosine diphosphate (GDP). Activation of the GPCR through extracellular agonist binding catalyzes the replacement of GDP with guanosine triphosphate (GTP), dissociation of both G α -GTP and a βγ heterodimer, and subsequent downstream effects. In the case of the μ-opioid receptor, the G α -GTP directly interacts with the potassium channel K ir 3 while the dissociated Gβγ subunit directly binds to and occludes the pore of P/Q-, N-, and L-type Ca channels. Furthermore, opioid receptor activation inhibits adenylyl cyclase, which in turn reduces cAMP-dependent Ca influx. By altering membrane ion conductivity, these effects modulate nociceptive signalling and produce an analgesic effect. In addition to the G-protein pathway, μ-opioid receptor activation can also result in downstream signalling through β-arrestin, which results in receptor internalization and is associated with negative effects of opioid use including respiratory depression, gastrointestinal effects, and desensitization/tolerance. Oliceridine acts as a "biased agonist" at the μ-opioid receptor by preferentially activating the G-protein pathway with minimal receptor phosphorylation and recruitment of β-arrestin. Competetive binding assays and structural modelling suggest that the binding site for oliceridine on the μ-opioid receptor is the same as for classical opioids. However, molecular modelling supports a model whereby oliceridine binding induces a different intracellular conformation of the μ-opioid receptor, specifically due to a lack of coupling with transmembrane helix six, which confers the specificity for G-protein over β-arrestin interaction. Numerous in vitro, in vivo, and clinical studies support the view that this biased agonism results in comparable analgesia compared with traditional opioids at a comparable or decreased risk of opioid-related adverse effects such as constipation and respiratory depression. •Absorption (Drug A): Bupropion is currently available in 3 distinct, but bioequivalent formulations: immediate release (IR), sustained-release (SR), and extended-release (XL). Immediate Release Formulation In humans, following oral administration of bupropion hydrochloride tablets, peak plasma bupropion concentrations are usually achieved within 2 hours. IR formulations provide a short duration of action and are therefore generally dosed three times per day. Sustained Release Formulation In humans, following oral administration of bupropion hydrochloride sustained-release tablets (SR), peak plasma concentration (Cmax) of bupropion is usually achieved within 3 hours. SR formulations provide a 12-hour extended release of medication and are therefore generally dosed twice per day. Extended Release Formulation Following single oral administration of bupropion hydrochloride extended-release tablets (XL) to healthy volunteers, the median time to peak plasma concentrations for bupropion was approximately 5 hours. The presence of food did not affect the peak concentration or area under the curve of bupropion. XL formulations provide a 24-hour extended release of medication and are therefore generally dosed once per day/ In a trial comparing chronic dosing with bupropion hydrochloride extended-release tablets (SR) 150 mg twice daily to bupropion immediate-release formulation 100 mg 3 times daily, the steady state Cmax for bupropion after bupropion hydrochloride sustained-release tablets (SR) administration was approximately 85% of those achieved after bupropion immediate-release formulation administration. Exposure (AUC) to bupropion was equivalent for both formulations. Bioequivalence was also demonstrated for all three major active metabolites (i.e., hydroxybupropion, threohydrobupropion and erythrohydrobupropion) for both Cmax and AUC. Thus, at steady state, bupropion hydrochloride sustained-release tablets (SR) given twice daily, and the immediate-release formulation of bupropion given 3 times daily, are essentially bioequivalent for both bupropion and the 3 quantitatively important metabolites. Furthermore, in a study comparing 14-day dosing with bupropion hydrochloride extended-release tablets (XL), 300 mg once-daily to the immediate-release formulation of bupropion at 100 mg 3 times daily, equivalence was demonstrated for peak plasma concentration and area under the curve for bupropion and the three metabolites (hydroxybupropion, threohydrobupropion, and erythrohydrobupropion). Additionally, in a study comparing 14-day dosing with bupropion hydrochloride extended-release tablets (XL) 300 mg once daily to the sustained-release formulation of bupropion at 150 mg 2 times daily, equivalence was demonstrated for peak plasma concentration and area under the curve for bupropion and the three metabolites. Bupropion hydrochloride extended-release tablets (SR) can be taken with or without food. Bupropion Cmax and AUC were increased by 11% to 35% and 16% to 19%, respectively, when bupropion hydrochloride extended-release tablets (SR) was administered with food to healthy volunteers in three trials. The food effect is not considered clinically significant. Following a single-dose administration of bupropion hydrochloride extended-release tablets (SR) in humans, Cmax of bupropion's metabolite hydroxybupropion occurs approximately 6 hours post-dose and is approximately 10 times the peak level of the parent drug at steady state. The elimination half-life of hydroxybupropion is approximately 20 (±5) hours and its AUC at steady state is about 17 times that of bupropion. The times to peak concentrations for the erythrohydrobupropion and threohydrobupropion metabolites are similar to that of the hydroxybupropion metabolite. However, their elimination half-lives are longer, 33(±10) and 37 (±13) hours, respectively, and steady-state AUCs are 1.5 and 7 times that of bupropion, respectively. •Absorption (Drug B): Oliceridine administered as a single intravenous injection of 1.5, 3, or 4.5 mg in healthy male volunteers had a corresponding C max of 47, 76, and 119 ng/mL and a corresponding AUC 0-24 of 43, 82, and 122 ng*h/mL. Simulations of single doses of oliceridine between 1-3 mg suggest that the expected median C max is between 43 and 130 ng/mL while the expected median AUC is between 22 and 70 ng*h/mL. •Volume of distribution (Drug A): No volume of distribution available •Volume of distribution (Drug B): Oliceridine has a mean steady-state volume of distribution of 90-120 L. •Protein binding (Drug A): In vitro tests show that bupropion is 84% bound to human plasma proteins at concentrations up to 200 mcg per mL. The extent of protein binding of the hydroxybupropion metabolite is similar to that for bupropion, whereas the extent of protein binding of the threohydrobupropion metabolite is about half that seen with bupropion. •Protein binding (Drug B): Oliceridine is approximately 77% bound to plasma proteins. •Metabolism (Drug A): Bupropion is extensively metabolized in humans. Three metabolites are active: hydroxybupropion, which is formed via hydroxylation of the tert-butyl group of bupropion, and the amino-alcohol isomers, threohydrobupropion and erythrohydrobupropion, which are formed via reduction of the carbonyl group. In vitro findings suggest that CYP2B6 is the principal isoenzyme involved in the formation of hydroxybupropion, while cytochrome P450 enzymes are not involved in the formation of threohydrobupropion. Hydroxybupropion has been shown to have the same affinity as bupropion for the norepinephrine transporter (NET) but approximately 50% of its antidepressant activity despite reaching concentrations of ~10-fold higher than that of the parent drug. Oxidation of the bupropion side chain results in the formation of a glycine conjugate of meta-chlorobenzoic acid, which is then excreted as the major urinary metabolite. The potency and toxicity of the metabolites relative to bupropion have not been fully characterized. However, it has been demonstrated in an antidepressant screening test in mice that hydroxybupropion is one-half as potent as bupropion, while threohydrobupropion and erythrohydrobupropion are 5-fold less potent than bupropion. This may be of clinical importance because the plasma concentrations of the metabolites are as high as or higher than those of bupropion. Bupropion and its metabolites exhibit linear kinetics following chronic administration of 300 to 450 mg per day. •Metabolism (Drug B): Oliceridine is primarily metabolized hepatically by CYP3A4 and CYP2D6 in vitro, with minor contributions from CYP2C9 and CYP2C19. None of oliceridine's metabolites are known to be active. Metabolic pathways include N-dealkylation, glucuronidation, and dehydrogenation. •Route of elimination (Drug A): Bupropion is extensively metabolized in humans. Oxidation of the bupropion side chain results in the formation of a glycine conjugate of metachlorobenzoic acid, which is then excreted as the major urinary metabolite. Following oral administration of 200 mg of 14C-bupropion in humans, 87% and 10% of the radioactive dose were recovered in the urine and feces, respectively. However, the fraction of the oral dose of bupropion excreted unchanged was only 0.5%, a finding consistent with the extensive metabolism of bupropion. •Route of elimination (Drug B): Approximately 70% of oliceridine is eliminated via the renal route, of which only 0.97-6.75% of an initial dose is recovered unchanged. The remaining 30% is eliminated in feces. •Half-life (Drug A): 24 hours •Half-life (Drug B): Oliceridine has a half-life of 1.3-3 hours while its metabolites, none of which are known to be active, have a substantially longer half-life of 44 hours. •Clearance (Drug A): No clearance available •Clearance (Drug B): Healthy volunteers given doses of oliceridine between 0.15 and 7 mg had mean clearance rates between 34 and 59.6 L/h. •Toxicity (Drug A): Symptoms of overdose include seizures, hallucinations, loss of consciousness, tachycardia, and cardiac arrest. •Toxicity (Drug B): Symptoms of oliceridine overdose are variable but can include respiratory depression, airway obstruction, pulmonary edema, bradycardia, hypotension, muscle flaccidity, cold skin, and somnolence progressing to either stupor or coma. Miosis is commonly observed but in cases of severe hypoxia, mydriasis may be observed instead. Oliceridine overdose may be fatal. In case of overdose, the establishment of a protected airway followed by the institution of assisted or controlled ventilation is a high priority; in case of cardiac arrhythmias or arrest, additional supportive measures may be immediately required. Supportive treatment, including oxygen, vasopressors, and the administration of an opioid antagonist such as naloxone may be applied but should be tailored to the individual patient's condition. •Brand Names (Drug A): Aplenzin, Auvelity, Budeprion, Contrave, Forfivo, Wellbutrin, Zyban •Brand Names (Drug B): Olinvyk •Synonyms (Drug A): No synonyms listed •Synonyms (Drug B): No synonyms listed •Summary (Drug A): Bupropion is a norepinephrine and dopamine reuptake inhibitor used in the treatment of major depressive disorder (MDD), seasonal affective disorder (SAD), and as an aid to smoking cessation. •Summary (Drug B): Oliceridine is a biased opioid agonist indicated for the management of severe acute pain in adult patients. Through preferential activation of G-protein-coupled signalling pathways, oliceridine provides analgesic effect with a comparable or improved safety profile over conventional opioid agonists. Output: Oliceridine displays an additive pharmacologic effect with CNS depressants such as benzodiazepines and alcohol, which increases the risk of hypotension, respiratory depression, sedation, coma, and death. The severity of the interaction is major.

Does Bupropion and Olodaterol interact?

•Drug A: Bupropion •Drug B: Olodaterol •Severity: MINOR •Description: The metabolism of Olodaterol can be decreased when combined with Bupropion. •Extended Description: Both of these agents are reported to be metabolized by CYP2C9. Concomitant administration of multiple CYP2C9 substrates can result in competition for the CYP2C9 binding sites and consequently reduced metabolism and increased plasma levels of one or both of the affected drugs. Elevated plasma levels may result in a higher incidence and/or severity of adverse effects. •Indication (Drug A): Bupropion is indicated for the treatment of major depressive disorder (MDD), seasonal affective disorder (SAD), and as an aid to smoking cessation. When used in combination with naltrexone as the marketed product ContraveⓇ, bupropion is indicated as an adjunct to a reduced-calorie diet and increased physical activity for chronic weight management in adults with an initial body mass index (BMI) of: 30 kg/m^2 or greater (obese) or 27 kg/m^2 or greater (overweight) in the presence of at least one weight-related comorbid condition (e.g., hypertension, type 2 diabetes mellitus, or dyslipidemia). Bupropion is also used off-label as a first-line treatment in patients with ADHD and comorbid bipolar disorder when used as an adjunct to mood stabilizers. •Indication (Drug B): Olodaterol is indicated for use in chronic obstructive pulmonary disease (COPD), including chronic bronchitis and/or emphysema. It is not indicated for the treatment of acute exacerbations of COPD or for the treatment of asthma. •Pharmacodynamics (Drug A): Bupropion is chemically unrelated to tricyclic, tetracyclic, selective serotonin re-uptake inhibitors, or other known antidepressant agents. Compared to classical tricyclic antidepressants, Bupropion is a relatively weak inhibitor of the neuronal uptake of norepinephrine and dopamine. In addition, Bupropion does not inhibit monoamine oxidase. Bupropion has been found to be essentially inactive at the serotonin transporter (SERT)(IC50 >10 000 nM), however both bupropion and its primary metabolite hydroxybupropion have been found to block the function of cation-selective serotonin type 3A receptors (5-HT3ARs). Bupropion produces dose-related central nervous system (CNS) stimulant effects in animals, as evidenced by increased locomotor activity, increased rates of responding in various schedule-controlled operant behaviour tasks, and, at high doses, induction of mild stereotyped behaviour. Due to these stimulant effects and selective activity at dopamine and norepinephrine receptors, bupropion has been identified as having an abuse potential. Bupropion has a similar structure to the controlled substance Cathinone, and has been identified as having mild amphetamine-like activity, particularly when inhaled or injected. Bupropion is also known to lower the seizure threshold, making any pre-existing seizure conditions a contraindication to its use. This risk is exacerbated when bupropion is combined with other drugs or substances that lower the seizure threshold, such as cocaine, or in clinical situations that would increase the risk of a seizure such as abrupt alcohol or benzodiazepine withdrawal. As norepinephrine has been shown to have anticonvulsant properties, bupropion's inhibitory effects on NET are thought to contribute to its pro-convulsant activity. Bupropion has been shown to increase blood pressure and pose a risk for exacerbation of unmanaged or pre-existing hypertension, however, clinical trials of bupropion in smokers with CVD have not identified an increased incidence of CV events including stroke or heart attack. In clinical trials, the mean increase in systolic blood pressure associated with the use of bupropion was found to be 1.3 mmHg. •Pharmacodynamics (Drug B): Olodaterol is a potent agonist of the human beta2-adrenergic receptor in vitro, and is highly selective for this receptor, with much lower levels of activity at the b1- and b3-adrenergic receptors that are commonly expressed on cardiac smooth muscle and adipose tissue, respectively. Binding to the receptor causes smooth muscle relaxation in the lungs and bronchodilation. It has also been shown to potently reverse active bronchoconstriction. •Mechanism of action (Drug A): Bupropion is a norepinephrine/dopamine-reuptake inhibitor (NDRI) that exerts its pharmacological effects by weakly inhibiting the enzymes involved in the uptake of the neurotransmitters norepinephrine and dopamine from the synaptic cleft, therefore prolonging their duration of action within the neuronal synapse and the downstream effects of these neurotransmitters. More specifically, bupropion binds to the norepinephrine transporter (NET) and the dopamine transporter (DAT). Bupropion was originally classified as an "atypical" antidepressant because it does not exert the same effects as the classical antidepressants such as Monoamine Oxidase Inhibitors (MAOIs), Tricyclic Antidepressants (TCAs), or Selective Serotonin Reuptake Inhibitors (SSRIs). While it has comparable effectiveness to typical first-line options for the treatment of depression such as SSRIs, bupropion is a unique option for the treatment of MDD as it lacks any clinically relevant serotonergic effects, typical of other mood medications, or any effects on histamine or adrenaline receptors. Lack of activity at these receptors results in a more tolerable side effect profile; bupropion is less likely to cause sexual side effects, sedation, or weight gain as compared to SSRIs or TCAs, for example. When used as an aid to smoking cessation, bupropion is thought to confer its anti-craving and anti-withdrawal effects by inhibiting dopamine reuptake, which is thought to be involved in the reward pathways associated with nicotine, and through the antagonism of the nicotinic acetylcholinergic receptor (AChR), thereby blunting the effects of nicotine. Furthermore, the stimulatory effects produced by bupropion in the central nervous system are similar to nicotine's effects, making low doses of bupropion a suitable option as a nicotine substitute. When used in combination with naltrexone in the marketed product ContraveⓇ for chronic weight management, the two components are thought to have effects on areas of the brain involved in the regulation of food intake. This includes the hypothalamus, which is involved in appetite regulation, and the mesolimbic dopamine circuit, which is involved in reward pathways. Studies have shown that the combined activity of bupropion and naltrexone increase the firing rate of hypothalamic pro-opiomelanocortin (POMC) neurons and blockade of opioid receptor-mediated POMC auto-inhibition, which are associated with a reduction in food intake and increased energy expenditure. This combination was also found to reduce food intake when injected directly into the ventral tegmental area of the mesolimbic circuit in mice, which is an area associated with the regulation of reward pathways. •Mechanism of action (Drug B): Olodaterol is a long-acting beta2-adrenergic agonist (LABA) that exerts its pharmacological effect by binding and activating beta2-adrenergic receptors located primarily in the lungs. Beta2-adrenergic receptors are membrane-bound receptors that are normally activated by endogenous epinephrine whose signalling, via a downstream L-type calcium channel interaction, mediates smooth muscle relaxation and bronchodilation. Activation of the receptor stimulates an associated G protein which then activates adenylate cyclase, catalyzing the formation of cyclic adenosine monophosphate (cAMP) and protein kinase A (PKA). Elevation of these two molecules induces bronchodilation by relaxation of airway smooth muscles. •Absorption (Drug A): Bupropion is currently available in 3 distinct, but bioequivalent formulations: immediate release (IR), sustained-release (SR), and extended-release (XL). Immediate Release Formulation In humans, following oral administration of bupropion hydrochloride tablets, peak plasma bupropion concentrations are usually achieved within 2 hours. IR formulations provide a short duration of action and are therefore generally dosed three times per day. Sustained Release Formulation In humans, following oral administration of bupropion hydrochloride sustained-release tablets (SR), peak plasma concentration (Cmax) of bupropion is usually achieved within 3 hours. SR formulations provide a 12-hour extended release of medication and are therefore generally dosed twice per day. Extended Release Formulation Following single oral administration of bupropion hydrochloride extended-release tablets (XL) to healthy volunteers, the median time to peak plasma concentrations for bupropion was approximately 5 hours. The presence of food did not affect the peak concentration or area under the curve of bupropion. XL formulations provide a 24-hour extended release of medication and are therefore generally dosed once per day/ In a trial comparing chronic dosing with bupropion hydrochloride extended-release tablets (SR) 150 mg twice daily to bupropion immediate-release formulation 100 mg 3 times daily, the steady state Cmax for bupropion after bupropion hydrochloride sustained-release tablets (SR) administration was approximately 85% of those achieved after bupropion immediate-release formulation administration. Exposure (AUC) to bupropion was equivalent for both formulations. Bioequivalence was also demonstrated for all three major active metabolites (i.e., hydroxybupropion, threohydrobupropion and erythrohydrobupropion) for both Cmax and AUC. Thus, at steady state, bupropion hydrochloride sustained-release tablets (SR) given twice daily, and the immediate-release formulation of bupropion given 3 times daily, are essentially bioequivalent for both bupropion and the 3 quantitatively important metabolites. Furthermore, in a study comparing 14-day dosing with bupropion hydrochloride extended-release tablets (XL), 300 mg once-daily to the immediate-release formulation of bupropion at 100 mg 3 times daily, equivalence was demonstrated for peak plasma concentration and area under the curve for bupropion and the three metabolites (hydroxybupropion, threohydrobupropion, and erythrohydrobupropion). Additionally, in a study comparing 14-day dosing with bupropion hydrochloride extended-release tablets (XL) 300 mg once daily to the sustained-release formulation of bupropion at 150 mg 2 times daily, equivalence was demonstrated for peak plasma concentration and area under the curve for bupropion and the three metabolites. Bupropion hydrochloride extended-release tablets (SR) can be taken with or without food. Bupropion Cmax and AUC were increased by 11% to 35% and 16% to 19%, respectively, when bupropion hydrochloride extended-release tablets (SR) was administered with food to healthy volunteers in three trials. The food effect is not considered clinically significant. Following a single-dose administration of bupropion hydrochloride extended-release tablets (SR) in humans, Cmax of bupropion's metabolite hydroxybupropion occurs approximately 6 hours post-dose and is approximately 10 times the peak level of the parent drug at steady state. The elimination half-life of hydroxybupropion is approximately 20 (±5) hours and its AUC at steady state is about 17 times that of bupropion. The times to peak concentrations for the erythrohydrobupropion and threohydrobupropion metabolites are similar to that of the hydroxybupropion metabolite. However, their elimination half-lives are longer, 33(±10) and 37 (±13) hours, respectively, and steady-state AUCs are 1.5 and 7 times that of bupropion, respectively. •Absorption (Drug B): Olodaterol reaches maximum plasma concentrations generally within 10 to 20 minutes following drug inhalation. In healthy volunteers, the absolute bioavailability of olodaterol following inhalation was estimated to be approximately 30%, whereas the absolute bioavailability was below 1% when given as an oral solution. Thus, the systemic availability of olodaterol after inhalation is mainly determined by lung absorption, while any swallowed portion of the dose only negligibly contributes to systemic exposure. •Volume of distribution (Drug A): No volume of distribution available •Volume of distribution (Drug B): The volume of distribution is high (1110 L), suggesting extensive distribution into tissue. •Protein binding (Drug A): In vitro tests show that bupropion is 84% bound to human plasma proteins at concentrations up to 200 mcg per mL. The extent of protein binding of the hydroxybupropion metabolite is similar to that for bupropion, whereas the extent of protein binding of the threohydrobupropion metabolite is about half that seen with bupropion. •Protein binding (Drug B): In vitro binding of olodaterol to human plasma proteins is independent of concentration and is approximately 60%. •Metabolism (Drug A): Bupropion is extensively metabolized in humans. Three metabolites are active: hydroxybupropion, which is formed via hydroxylation of the tert-butyl group of bupropion, and the amino-alcohol isomers, threohydrobupropion and erythrohydrobupropion, which are formed via reduction of the carbonyl group. In vitro findings suggest that CYP2B6 is the principal isoenzyme involved in the formation of hydroxybupropion, while cytochrome P450 enzymes are not involved in the formation of threohydrobupropion. Hydroxybupropion has been shown to have the same affinity as bupropion for the norepinephrine transporter (NET) but approximately 50% of its antidepressant activity despite reaching concentrations of ~10-fold higher than that of the parent drug. Oxidation of the bupropion side chain results in the formation of a glycine conjugate of meta-chlorobenzoic acid, which is then excreted as the major urinary metabolite. The potency and toxicity of the metabolites relative to bupropion have not been fully characterized. However, it has been demonstrated in an antidepressant screening test in mice that hydroxybupropion is one-half as potent as bupropion, while threohydrobupropion and erythrohydrobupropion are 5-fold less potent than bupropion. This may be of clinical importance because the plasma concentrations of the metabolites are as high as or higher than those of bupropion. Bupropion and its metabolites exhibit linear kinetics following chronic administration of 300 to 450 mg per day. •Metabolism (Drug B): Olodaterol is substantially metabolized by direct glucuronidation and by O-demethylation at the methoxy moiety followed by conjugation. Of the six metabolites identified, only the unconjugated demethylation product binds to beta2-receptors. This metabolite, however, is not detectable in plasma after chronic inhalation of the recommended therapeutic dose. Cytochrome P450 isozymes CYP2C9 and CYP2C8, with negligible contribution of CYP3A4, are involved in the O-demethylation of olodaterol, while uridine diphosphate glycosyl transferase isoforms UGT2B7, UGT1A1, 1A7, and 1A9 were shown to be involved in the formation of olodaterol glucuronides. •Route of elimination (Drug A): Bupropion is extensively metabolized in humans. Oxidation of the bupropion side chain results in the formation of a glycine conjugate of metachlorobenzoic acid, which is then excreted as the major urinary metabolite. Following oral administration of 200 mg of 14C-bupropion in humans, 87% and 10% of the radioactive dose were recovered in the urine and feces, respectively. However, the fraction of the oral dose of bupropion excreted unchanged was only 0.5%, a finding consistent with the extensive metabolism of bupropion. •Route of elimination (Drug B): Following intravenous administration of [14C]-labeled olodaterol, 38% of the radioactive dose was recovered in the urine and 53% was recovered in feces. The amount of unchanged olodaterol recovered in the urine after intravenous administration was 19%. Following oral administration, only 9% of olodaterol and/or its metabolites was recovered in urine, while the major portion was recovered in feces (84%). •Half-life (Drug A): 24 hours •Half-life (Drug B): The terminal half-life following intravenous administration is 22 hours. The terminal half-life following inhalation in contrast is about 45 hours, indicating that the latter is determined by absorption rather than by elimination processes. •Clearance (Drug A): No clearance available •Clearance (Drug B): Total clearance of olodaterol in healthy volunteers is 872 mL/min, and renal clearance is 173 mL/min. •Toxicity (Drug A): Symptoms of overdose include seizures, hallucinations, loss of consciousness, tachycardia, and cardiac arrest. •Toxicity (Drug B): Adverse drug reactions that occurred at a frequency greater than 2% include nasopharyngitis (11.3%), upper respiratory tract infection (8.2%), bronchitis (4.7%), urinary tract infection (2.5%), cough (4.2%), dizziness (2.3%), rash (2.2%), diarrhea (2.9%), back pain (3.5%), and arthralgia (2.1%). •Brand Names (Drug A): Aplenzin, Auvelity, Budeprion, Contrave, Forfivo, Wellbutrin, Zyban •Brand Names (Drug B): Inspiolto Respimat, Stiolto, Striverdi Respimat •Synonyms (Drug A): No synonyms listed •Synonyms (Drug B): No synonyms listed •Summary (Drug A): Bupropion is a norepinephrine and dopamine reuptake inhibitor used in the treatment of major depressive disorder (MDD), seasonal affective disorder (SAD), and as an aid to smoking cessation. •Summary (Drug B): Olodaterol is a long-acting beta2-adrenergic agonist used in the management of chronic obstructive pulmonary disease (COPD), including chronic bronchitis and/or emphysema.

Both of these agents are reported to be metabolized by CYP2C9. Concomitant administration of multiple CYP2C9 substrates can result in competition for the CYP2C9 binding sites and consequently reduced metabolism and increased plasma levels of one or both of the affected drugs. Elevated plasma levels may result in a higher incidence and/or severity of adverse effects. The severity of the interaction is minor.

Question: Does Bupropion and Olodaterol interact? Information: •Drug A: Bupropion •Drug B: Olodaterol •Severity: MINOR •Description: The metabolism of Olodaterol can be decreased when combined with Bupropion. •Extended Description: Both of these agents are reported to be metabolized by CYP2C9. Concomitant administration of multiple CYP2C9 substrates can result in competition for the CYP2C9 binding sites and consequently reduced metabolism and increased plasma levels of one or both of the affected drugs. Elevated plasma levels may result in a higher incidence and/or severity of adverse effects. •Indication (Drug A): Bupropion is indicated for the treatment of major depressive disorder (MDD), seasonal affective disorder (SAD), and as an aid to smoking cessation. When used in combination with naltrexone as the marketed product ContraveⓇ, bupropion is indicated as an adjunct to a reduced-calorie diet and increased physical activity for chronic weight management in adults with an initial body mass index (BMI) of: 30 kg/m^2 or greater (obese) or 27 kg/m^2 or greater (overweight) in the presence of at least one weight-related comorbid condition (e.g., hypertension, type 2 diabetes mellitus, or dyslipidemia). Bupropion is also used off-label as a first-line treatment in patients with ADHD and comorbid bipolar disorder when used as an adjunct to mood stabilizers. •Indication (Drug B): Olodaterol is indicated for use in chronic obstructive pulmonary disease (COPD), including chronic bronchitis and/or emphysema. It is not indicated for the treatment of acute exacerbations of COPD or for the treatment of asthma. •Pharmacodynamics (Drug A): Bupropion is chemically unrelated to tricyclic, tetracyclic, selective serotonin re-uptake inhibitors, or other known antidepressant agents. Compared to classical tricyclic antidepressants, Bupropion is a relatively weak inhibitor of the neuronal uptake of norepinephrine and dopamine. In addition, Bupropion does not inhibit monoamine oxidase. Bupropion has been found to be essentially inactive at the serotonin transporter (SERT)(IC50 >10 000 nM), however both bupropion and its primary metabolite hydroxybupropion have been found to block the function of cation-selective serotonin type 3A receptors (5-HT3ARs). Bupropion produces dose-related central nervous system (CNS) stimulant effects in animals, as evidenced by increased locomotor activity, increased rates of responding in various schedule-controlled operant behaviour tasks, and, at high doses, induction of mild stereotyped behaviour. Due to these stimulant effects and selective activity at dopamine and norepinephrine receptors, bupropion has been identified as having an abuse potential. Bupropion has a similar structure to the controlled substance Cathinone, and has been identified as having mild amphetamine-like activity, particularly when inhaled or injected. Bupropion is also known to lower the seizure threshold, making any pre-existing seizure conditions a contraindication to its use. This risk is exacerbated when bupropion is combined with other drugs or substances that lower the seizure threshold, such as cocaine, or in clinical situations that would increase the risk of a seizure such as abrupt alcohol or benzodiazepine withdrawal. As norepinephrine has been shown to have anticonvulsant properties, bupropion's inhibitory effects on NET are thought to contribute to its pro-convulsant activity. Bupropion has been shown to increase blood pressure and pose a risk for exacerbation of unmanaged or pre-existing hypertension, however, clinical trials of bupropion in smokers with CVD have not identified an increased incidence of CV events including stroke or heart attack. In clinical trials, the mean increase in systolic blood pressure associated with the use of bupropion was found to be 1.3 mmHg. •Pharmacodynamics (Drug B): Olodaterol is a potent agonist of the human beta2-adrenergic receptor in vitro, and is highly selective for this receptor, with much lower levels of activity at the b1- and b3-adrenergic receptors that are commonly expressed on cardiac smooth muscle and adipose tissue, respectively. Binding to the receptor causes smooth muscle relaxation in the lungs and bronchodilation. It has also been shown to potently reverse active bronchoconstriction. •Mechanism of action (Drug A): Bupropion is a norepinephrine/dopamine-reuptake inhibitor (NDRI) that exerts its pharmacological effects by weakly inhibiting the enzymes involved in the uptake of the neurotransmitters norepinephrine and dopamine from the synaptic cleft, therefore prolonging their duration of action within the neuronal synapse and the downstream effects of these neurotransmitters. More specifically, bupropion binds to the norepinephrine transporter (NET) and the dopamine transporter (DAT). Bupropion was originally classified as an "atypical" antidepressant because it does not exert the same effects as the classical antidepressants such as Monoamine Oxidase Inhibitors (MAOIs), Tricyclic Antidepressants (TCAs), or Selective Serotonin Reuptake Inhibitors (SSRIs). While it has comparable effectiveness to typical first-line options for the treatment of depression such as SSRIs, bupropion is a unique option for the treatment of MDD as it lacks any clinically relevant serotonergic effects, typical of other mood medications, or any effects on histamine or adrenaline receptors. Lack of activity at these receptors results in a more tolerable side effect profile; bupropion is less likely to cause sexual side effects, sedation, or weight gain as compared to SSRIs or TCAs, for example. When used as an aid to smoking cessation, bupropion is thought to confer its anti-craving and anti-withdrawal effects by inhibiting dopamine reuptake, which is thought to be involved in the reward pathways associated with nicotine, and through the antagonism of the nicotinic acetylcholinergic receptor (AChR), thereby blunting the effects of nicotine. Furthermore, the stimulatory effects produced by bupropion in the central nervous system are similar to nicotine's effects, making low doses of bupropion a suitable option as a nicotine substitute. When used in combination with naltrexone in the marketed product ContraveⓇ for chronic weight management, the two components are thought to have effects on areas of the brain involved in the regulation of food intake. This includes the hypothalamus, which is involved in appetite regulation, and the mesolimbic dopamine circuit, which is involved in reward pathways. Studies have shown that the combined activity of bupropion and naltrexone increase the firing rate of hypothalamic pro-opiomelanocortin (POMC) neurons and blockade of opioid receptor-mediated POMC auto-inhibition, which are associated with a reduction in food intake and increased energy expenditure. This combination was also found to reduce food intake when injected directly into the ventral tegmental area of the mesolimbic circuit in mice, which is an area associated with the regulation of reward pathways. •Mechanism of action (Drug B): Olodaterol is a long-acting beta2-adrenergic agonist (LABA) that exerts its pharmacological effect by binding and activating beta2-adrenergic receptors located primarily in the lungs. Beta2-adrenergic receptors are membrane-bound receptors that are normally activated by endogenous epinephrine whose signalling, via a downstream L-type calcium channel interaction, mediates smooth muscle relaxation and bronchodilation. Activation of the receptor stimulates an associated G protein which then activates adenylate cyclase, catalyzing the formation of cyclic adenosine monophosphate (cAMP) and protein kinase A (PKA). Elevation of these two molecules induces bronchodilation by relaxation of airway smooth muscles. •Absorption (Drug A): Bupropion is currently available in 3 distinct, but bioequivalent formulations: immediate release (IR), sustained-release (SR), and extended-release (XL). Immediate Release Formulation In humans, following oral administration of bupropion hydrochloride tablets, peak plasma bupropion concentrations are usually achieved within 2 hours. IR formulations provide a short duration of action and are therefore generally dosed three times per day. Sustained Release Formulation In humans, following oral administration of bupropion hydrochloride sustained-release tablets (SR), peak plasma concentration (Cmax) of bupropion is usually achieved within 3 hours. SR formulations provide a 12-hour extended release of medication and are therefore generally dosed twice per day. Extended Release Formulation Following single oral administration of bupropion hydrochloride extended-release tablets (XL) to healthy volunteers, the median time to peak plasma concentrations for bupropion was approximately 5 hours. The presence of food did not affect the peak concentration or area under the curve of bupropion. XL formulations provide a 24-hour extended release of medication and are therefore generally dosed once per day/ In a trial comparing chronic dosing with bupropion hydrochloride extended-release tablets (SR) 150 mg twice daily to bupropion immediate-release formulation 100 mg 3 times daily, the steady state Cmax for bupropion after bupropion hydrochloride sustained-release tablets (SR) administration was approximately 85% of those achieved after bupropion immediate-release formulation administration. Exposure (AUC) to bupropion was equivalent for both formulations. Bioequivalence was also demonstrated for all three major active metabolites (i.e., hydroxybupropion, threohydrobupropion and erythrohydrobupropion) for both Cmax and AUC. Thus, at steady state, bupropion hydrochloride sustained-release tablets (SR) given twice daily, and the immediate-release formulation of bupropion given 3 times daily, are essentially bioequivalent for both bupropion and the 3 quantitatively important metabolites. Furthermore, in a study comparing 14-day dosing with bupropion hydrochloride extended-release tablets (XL), 300 mg once-daily to the immediate-release formulation of bupropion at 100 mg 3 times daily, equivalence was demonstrated for peak plasma concentration and area under the curve for bupropion and the three metabolites (hydroxybupropion, threohydrobupropion, and erythrohydrobupropion). Additionally, in a study comparing 14-day dosing with bupropion hydrochloride extended-release tablets (XL) 300 mg once daily to the sustained-release formulation of bupropion at 150 mg 2 times daily, equivalence was demonstrated for peak plasma concentration and area under the curve for bupropion and the three metabolites. Bupropion hydrochloride extended-release tablets (SR) can be taken with or without food. Bupropion Cmax and AUC were increased by 11% to 35% and 16% to 19%, respectively, when bupropion hydrochloride extended-release tablets (SR) was administered with food to healthy volunteers in three trials. The food effect is not considered clinically significant. Following a single-dose administration of bupropion hydrochloride extended-release tablets (SR) in humans, Cmax of bupropion's metabolite hydroxybupropion occurs approximately 6 hours post-dose and is approximately 10 times the peak level of the parent drug at steady state. The elimination half-life of hydroxybupropion is approximately 20 (±5) hours and its AUC at steady state is about 17 times that of bupropion. The times to peak concentrations for the erythrohydrobupropion and threohydrobupropion metabolites are similar to that of the hydroxybupropion metabolite. However, their elimination half-lives are longer, 33(±10) and 37 (±13) hours, respectively, and steady-state AUCs are 1.5 and 7 times that of bupropion, respectively. •Absorption (Drug B): Olodaterol reaches maximum plasma concentrations generally within 10 to 20 minutes following drug inhalation. In healthy volunteers, the absolute bioavailability of olodaterol following inhalation was estimated to be approximately 30%, whereas the absolute bioavailability was below 1% when given as an oral solution. Thus, the systemic availability of olodaterol after inhalation is mainly determined by lung absorption, while any swallowed portion of the dose only negligibly contributes to systemic exposure. •Volume of distribution (Drug A): No volume of distribution available •Volume of distribution (Drug B): The volume of distribution is high (1110 L), suggesting extensive distribution into tissue. •Protein binding (Drug A): In vitro tests show that bupropion is 84% bound to human plasma proteins at concentrations up to 200 mcg per mL. The extent of protein binding of the hydroxybupropion metabolite is similar to that for bupropion, whereas the extent of protein binding of the threohydrobupropion metabolite is about half that seen with bupropion. •Protein binding (Drug B): In vitro binding of olodaterol to human plasma proteins is independent of concentration and is approximately 60%. •Metabolism (Drug A): Bupropion is extensively metabolized in humans. Three metabolites are active: hydroxybupropion, which is formed via hydroxylation of the tert-butyl group of bupropion, and the amino-alcohol isomers, threohydrobupropion and erythrohydrobupropion, which are formed via reduction of the carbonyl group. In vitro findings suggest that CYP2B6 is the principal isoenzyme involved in the formation of hydroxybupropion, while cytochrome P450 enzymes are not involved in the formation of threohydrobupropion. Hydroxybupropion has been shown to have the same affinity as bupropion for the norepinephrine transporter (NET) but approximately 50% of its antidepressant activity despite reaching concentrations of ~10-fold higher than that of the parent drug. Oxidation of the bupropion side chain results in the formation of a glycine conjugate of meta-chlorobenzoic acid, which is then excreted as the major urinary metabolite. The potency and toxicity of the metabolites relative to bupropion have not been fully characterized. However, it has been demonstrated in an antidepressant screening test in mice that hydroxybupropion is one-half as potent as bupropion, while threohydrobupropion and erythrohydrobupropion are 5-fold less potent than bupropion. This may be of clinical importance because the plasma concentrations of the metabolites are as high as or higher than those of bupropion. Bupropion and its metabolites exhibit linear kinetics following chronic administration of 300 to 450 mg per day. •Metabolism (Drug B): Olodaterol is substantially metabolized by direct glucuronidation and by O-demethylation at the methoxy moiety followed by conjugation. Of the six metabolites identified, only the unconjugated demethylation product binds to beta2-receptors. This metabolite, however, is not detectable in plasma after chronic inhalation of the recommended therapeutic dose. Cytochrome P450 isozymes CYP2C9 and CYP2C8, with negligible contribution of CYP3A4, are involved in the O-demethylation of olodaterol, while uridine diphosphate glycosyl transferase isoforms UGT2B7, UGT1A1, 1A7, and 1A9 were shown to be involved in the formation of olodaterol glucuronides. •Route of elimination (Drug A): Bupropion is extensively metabolized in humans. Oxidation of the bupropion side chain results in the formation of a glycine conjugate of metachlorobenzoic acid, which is then excreted as the major urinary metabolite. Following oral administration of 200 mg of 14C-bupropion in humans, 87% and 10% of the radioactive dose were recovered in the urine and feces, respectively. However, the fraction of the oral dose of bupropion excreted unchanged was only 0.5%, a finding consistent with the extensive metabolism of bupropion. •Route of elimination (Drug B): Following intravenous administration of [14C]-labeled olodaterol, 38% of the radioactive dose was recovered in the urine and 53% was recovered in feces. The amount of unchanged olodaterol recovered in the urine after intravenous administration was 19%. Following oral administration, only 9% of olodaterol and/or its metabolites was recovered in urine, while the major portion was recovered in feces (84%). •Half-life (Drug A): 24 hours •Half-life (Drug B): The terminal half-life following intravenous administration is 22 hours. The terminal half-life following inhalation in contrast is about 45 hours, indicating that the latter is determined by absorption rather than by elimination processes. •Clearance (Drug A): No clearance available •Clearance (Drug B): Total clearance of olodaterol in healthy volunteers is 872 mL/min, and renal clearance is 173 mL/min. •Toxicity (Drug A): Symptoms of overdose include seizures, hallucinations, loss of consciousness, tachycardia, and cardiac arrest. •Toxicity (Drug B): Adverse drug reactions that occurred at a frequency greater than 2% include nasopharyngitis (11.3%), upper respiratory tract infection (8.2%), bronchitis (4.7%), urinary tract infection (2.5%), cough (4.2%), dizziness (2.3%), rash (2.2%), diarrhea (2.9%), back pain (3.5%), and arthralgia (2.1%). •Brand Names (Drug A): Aplenzin, Auvelity, Budeprion, Contrave, Forfivo, Wellbutrin, Zyban •Brand Names (Drug B): Inspiolto Respimat, Stiolto, Striverdi Respimat •Synonyms (Drug A): No synonyms listed •Synonyms (Drug B): No synonyms listed •Summary (Drug A): Bupropion is a norepinephrine and dopamine reuptake inhibitor used in the treatment of major depressive disorder (MDD), seasonal affective disorder (SAD), and as an aid to smoking cessation. •Summary (Drug B): Olodaterol is a long-acting beta2-adrenergic agonist used in the management of chronic obstructive pulmonary disease (COPD), including chronic bronchitis and/or emphysema. Output: Both of these agents are reported to be metabolized by CYP2C9. Concomitant administration of multiple CYP2C9 substrates can result in competition for the CYP2C9 binding sites and consequently reduced metabolism and increased plasma levels of one or both of the affected drugs. Elevated plasma levels may result in a higher incidence and/or severity of adverse effects. The severity of the interaction is minor.

Does Bupropion and Olsalazine interact?

•Drug A: Bupropion •Drug B: Olsalazine •Severity: MINOR •Description: Olsalazine may decrease the excretion rate of Bupropion which could result in a higher serum level. •Extended Description: The subject drug is a nephrotoxic agent that may potentially impair renal function and decrease the excretion of drugs that mainly undergo renal excretion as the principal mode of clearance, such as the affected drug. Attenuated renal excretion of the affected drug may increase drug concentrations, leading to an elevated risk for drug-related adverse effects. •Indication (Drug A): Bupropion is indicated for the treatment of major depressive disorder (MDD), seasonal affective disorder (SAD), and as an aid to smoking cessation. When used in combination with naltrexone as the marketed product ContraveⓇ, bupropion is indicated as an adjunct to a reduced-calorie diet and increased physical activity for chronic weight management in adults with an initial body mass index (BMI) of: 30 kg/m^2 or greater (obese) or 27 kg/m^2 or greater (overweight) in the presence of at least one weight-related comorbid condition (e.g., hypertension, type 2 diabetes mellitus, or dyslipidemia). Bupropion is also used off-label as a first-line treatment in patients with ADHD and comorbid bipolar disorder when used as an adjunct to mood stabilizers. •Indication (Drug B): In the US, olsalazine is indicated for the maintenance of remission of ulcerative colitis in adult patients who are intolerant to sulfasalazine. In Canada, it is used in the treatment of acute ulcerative colitis of mild to moderate severity, with or without the concomitant use of steroids. It is also indicated for the long-term maintenance of patients with ulcerative colitis in remission. •Pharmacodynamics (Drug A): Bupropion is chemically unrelated to tricyclic, tetracyclic, selective serotonin re-uptake inhibitors, or other known antidepressant agents. Compared to classical tricyclic antidepressants, Bupropion is a relatively weak inhibitor of the neuronal uptake of norepinephrine and dopamine. In addition, Bupropion does not inhibit monoamine oxidase. Bupropion has been found to be essentially inactive at the serotonin transporter (SERT)(IC50 >10 000 nM), however both bupropion and its primary metabolite hydroxybupropion have been found to block the function of cation-selective serotonin type 3A receptors (5-HT3ARs). Bupropion produces dose-related central nervous system (CNS) stimulant effects in animals, as evidenced by increased locomotor activity, increased rates of responding in various schedule-controlled operant behaviour tasks, and, at high doses, induction of mild stereotyped behaviour. Due to these stimulant effects and selective activity at dopamine and norepinephrine receptors, bupropion has been identified as having an abuse potential. Bupropion has a similar structure to the controlled substance Cathinone, and has been identified as having mild amphetamine-like activity, particularly when inhaled or injected. Bupropion is also known to lower the seizure threshold, making any pre-existing seizure conditions a contraindication to its use. This risk is exacerbated when bupropion is combined with other drugs or substances that lower the seizure threshold, such as cocaine, or in clinical situations that would increase the risk of a seizure such as abrupt alcohol or benzodiazepine withdrawal. As norepinephrine has been shown to have anticonvulsant properties, bupropion's inhibitory effects on NET are thought to contribute to its pro-convulsant activity. Bupropion has been shown to increase blood pressure and pose a risk for exacerbation of unmanaged or pre-existing hypertension, however, clinical trials of bupropion in smokers with CVD have not identified an increased incidence of CV events including stroke or heart attack. In clinical trials, the mean increase in systolic blood pressure associated with the use of bupropion was found to be 1.3 mmHg. •Pharmacodynamics (Drug B): Olsalazine is an anti-inflammatory agent that blocks the production of cyclooxygenase (COX)-derived products of arachidonic acid metabolism. It works to alleviate inflammation in ulcerative colitis. Olsalazine was shown to decrease water and sodium absorption. While olsalazine is not expected to affect the motility and transit time of small intestines, it decreased small bowel transit time at high doses ranging from 60 to 120 mg/kg. In about 40% of the patients with ulcerative colitis, administration of olsalazine 1g daily was associated with a decrease in whole gut transit time. •Mechanism of action (Drug A): Bupropion is a norepinephrine/dopamine-reuptake inhibitor (NDRI) that exerts its pharmacological effects by weakly inhibiting the enzymes involved in the uptake of the neurotransmitters norepinephrine and dopamine from the synaptic cleft, therefore prolonging their duration of action within the neuronal synapse and the downstream effects of these neurotransmitters. More specifically, bupropion binds to the norepinephrine transporter (NET) and the dopamine transporter (DAT). Bupropion was originally classified as an "atypical" antidepressant because it does not exert the same effects as the classical antidepressants such as Monoamine Oxidase Inhibitors (MAOIs), Tricyclic Antidepressants (TCAs), or Selective Serotonin Reuptake Inhibitors (SSRIs). While it has comparable effectiveness to typical first-line options for the treatment of depression such as SSRIs, bupropion is a unique option for the treatment of MDD as it lacks any clinically relevant serotonergic effects, typical of other mood medications, or any effects on histamine or adrenaline receptors. Lack of activity at these receptors results in a more tolerable side effect profile; bupropion is less likely to cause sexual side effects, sedation, or weight gain as compared to SSRIs or TCAs, for example. When used as an aid to smoking cessation, bupropion is thought to confer its anti-craving and anti-withdrawal effects by inhibiting dopamine reuptake, which is thought to be involved in the reward pathways associated with nicotine, and through the antagonism of the nicotinic acetylcholinergic receptor (AChR), thereby blunting the effects of nicotine. Furthermore, the stimulatory effects produced by bupropion in the central nervous system are similar to nicotine's effects, making low doses of bupropion a suitable option as a nicotine substitute. When used in combination with naltrexone in the marketed product ContraveⓇ for chronic weight management, the two components are thought to have effects on areas of the brain involved in the regulation of food intake. This includes the hypothalamus, which is involved in appetite regulation, and the mesolimbic dopamine circuit, which is involved in reward pathways. Studies have shown that the combined activity of bupropion and naltrexone increase the firing rate of hypothalamic pro-opiomelanocortin (POMC) neurons and blockade of opioid receptor-mediated POMC auto-inhibition, which are associated with a reduction in food intake and increased energy expenditure. This combination was also found to reduce food intake when injected directly into the ventral tegmental area of the mesolimbic circuit in mice, which is an area associated with the regulation of reward pathways. •Mechanism of action (Drug B): Upon administration, the azo bond connecting two molecules of mesalamine (also known as 5-aminosalicylic acid or 5-ASA) is cleaved by azoreductase-containing bacteria in the colon. The two molecules of mesalamine are released to mediate therapeutic effects. The exact mechanism of action of olsalazine and its active moiety mesalamine in ulcerative colitis has not been elucidated; however, it is understood that mesalamine mediates an anti-inflammatory action on epithelial cells of the colon. The COX-derived (i.e., prostanoids such as prostaglandin E2) and lipoxygenase-derived products (i.e., leukotrienes [LTs] and hydroxyeicosatetraenoic acids [HETEs]) of arachidonic acid metabolism have been implicated in the pathogenesis and maintenance of inflammatory disorders, including ulcerative colitis and inflammatory bowel disease. Mesalamine may attenuate inflammation by blocking the COX enzyme and inhibiting prostaglandin production in the colon. Olsalazine was also shown to inhibit xanthine oxidase, an enzyme that generates oxygen-derived free radicals. Olsalazine may attenuate intestinal inflammation by limiting macrophage migration to inflamed intestinal mucosa: it was shown to inhibit in vitro migration of intestinal macrophages in response to leukotriene B 4. Olsalazine may also act as a free radical scavenger, and mesalazine may suppress fatty acid peroxidation. •Absorption (Drug A): Bupropion is currently available in 3 distinct, but bioequivalent formulations: immediate release (IR), sustained-release (SR), and extended-release (XL). Immediate Release Formulation In humans, following oral administration of bupropion hydrochloride tablets, peak plasma bupropion concentrations are usually achieved within 2 hours. IR formulations provide a short duration of action and are therefore generally dosed three times per day. Sustained Release Formulation In humans, following oral administration of bupropion hydrochloride sustained-release tablets (SR), peak plasma concentration (Cmax) of bupropion is usually achieved within 3 hours. SR formulations provide a 12-hour extended release of medication and are therefore generally dosed twice per day. Extended Release Formulation Following single oral administration of bupropion hydrochloride extended-release tablets (XL) to healthy volunteers, the median time to peak plasma concentrations for bupropion was approximately 5 hours. The presence of food did not affect the peak concentration or area under the curve of bupropion. XL formulations provide a 24-hour extended release of medication and are therefore generally dosed once per day/ In a trial comparing chronic dosing with bupropion hydrochloride extended-release tablets (SR) 150 mg twice daily to bupropion immediate-release formulation 100 mg 3 times daily, the steady state Cmax for bupropion after bupropion hydrochloride sustained-release tablets (SR) administration was approximately 85% of those achieved after bupropion immediate-release formulation administration. Exposure (AUC) to bupropion was equivalent for both formulations. Bioequivalence was also demonstrated for all three major active metabolites (i.e., hydroxybupropion, threohydrobupropion and erythrohydrobupropion) for both Cmax and AUC. Thus, at steady state, bupropion hydrochloride sustained-release tablets (SR) given twice daily, and the immediate-release formulation of bupropion given 3 times daily, are essentially bioequivalent for both bupropion and the 3 quantitatively important metabolites. Furthermore, in a study comparing 14-day dosing with bupropion hydrochloride extended-release tablets (XL), 300 mg once-daily to the immediate-release formulation of bupropion at 100 mg 3 times daily, equivalence was demonstrated for peak plasma concentration and area under the curve for bupropion and the three metabolites (hydroxybupropion, threohydrobupropion, and erythrohydrobupropion). Additionally, in a study comparing 14-day dosing with bupropion hydrochloride extended-release tablets (XL) 300 mg once daily to the sustained-release formulation of bupropion at 150 mg 2 times daily, equivalence was demonstrated for peak plasma concentration and area under the curve for bupropion and the three metabolites. Bupropion hydrochloride extended-release tablets (SR) can be taken with or without food. Bupropion Cmax and AUC were increased by 11% to 35% and 16% to 19%, respectively, when bupropion hydrochloride extended-release tablets (SR) was administered with food to healthy volunteers in three trials. The food effect is not considered clinically significant. Following a single-dose administration of bupropion hydrochloride extended-release tablets (SR) in humans, Cmax of bupropion's metabolite hydroxybupropion occurs approximately 6 hours post-dose and is approximately 10 times the peak level of the parent drug at steady state. The elimination half-life of hydroxybupropion is approximately 20 (±5) hours and its AUC at steady state is about 17 times that of bupropion. The times to peak concentrations for the erythrohydrobupropion and threohydrobupropion metabolites are similar to that of the hydroxybupropion metabolite. However, their elimination half-lives are longer, 33(±10) and 37 (±13) hours, respectively, and steady-state AUCs are 1.5 and 7 times that of bupropion, respectively. •Absorption (Drug B): After oral administration, olsalazine has limited systemic bioavailability, with less than 5% of the oral dose being absorbed. Based on oral and intravenous dosing studies, approximately 2.4% of a single 1 g oral dose is absorbed. Maximum serum concentrations of olsalazine appear after approximately one hour and, even after a 1 g single dose, are low (e.g., 1.6 to 6.2 µmol/L). Patients on daily doses of 1 g olsalazine for two to four years show a stable plasma concentration of olsalazine-S (3.3 to 12.4 µmol/L). Olsalazine-S accumulates to a steady state within two to three weeks. Serum concentrations of mesalamine are detected after four to eight hours. The peak levels of mesalamine after an oral dose of 1 g olsalazine are low (i.e., 0 to 4.3 µmol/L). •Volume of distribution (Drug A): No volume of distribution available •Volume of distribution (Drug B): The steady-state volume of distribution determined in healthy volunteers is approximately 5L. •Protein binding (Drug A): In vitro tests show that bupropion is 84% bound to human plasma proteins at concentrations up to 200 mcg per mL. The extent of protein binding of the hydroxybupropion metabolite is similar to that for bupropion, whereas the extent of protein binding of the threohydrobupropion metabolite is about half that seen with bupropion. •Protein binding (Drug B): Olsalazine and its metabolite olsalazine-S, are more than 99% bound to plasma proteins. Less than 1% of both olsalazine and olsalazine-S appears undissociated in plasma. It does not interfere with the protein binding of warfarin. Mesalamine (5-aminosalicylic acid, 5-ASA) and its metabolite, N-acetyl-5-ASA, are 74 and 81%, respectively, bound to plasma proteins. •Metabolism (Drug A): Bupropion is extensively metabolized in humans. Three metabolites are active: hydroxybupropion, which is formed via hydroxylation of the tert-butyl group of bupropion, and the amino-alcohol isomers, threohydrobupropion and erythrohydrobupropion, which are formed via reduction of the carbonyl group. In vitro findings suggest that CYP2B6 is the principal isoenzyme involved in the formation of hydroxybupropion, while cytochrome P450 enzymes are not involved in the formation of threohydrobupropion. Hydroxybupropion has been shown to have the same affinity as bupropion for the norepinephrine transporter (NET) but approximately 50% of its antidepressant activity despite reaching concentrations of ~10-fold higher than that of the parent drug. Oxidation of the bupropion side chain results in the formation of a glycine conjugate of meta-chlorobenzoic acid, which is then excreted as the major urinary metabolite. The potency and toxicity of the metabolites relative to bupropion have not been fully characterized. However, it has been demonstrated in an antidepressant screening test in mice that hydroxybupropion is one-half as potent as bupropion, while threohydrobupropion and erythrohydrobupropion are 5-fold less potent than bupropion. This may be of clinical importance because the plasma concentrations of the metabolites are as high as or higher than those of bupropion. Bupropion and its metabolites exhibit linear kinetics following chronic administration of 300 to 450 mg per day. •Metabolism (Drug B): Olsalazine is cleaved by colonic bacteria to release its active ingredient, mesalamine. Mesalamine can undergo acetylation to form N-acetyl-5-aminosalicylic acid (N-acetyl-5-ASA, Ac-5-ASA) by the colonic epithelium; however, the extent of acetylation depends on transit time. Approximately 0.1% of an oral dose of olsalazine is metabolized in the liver to olsalazine-O-sulfate (olsalazine-S). •Route of elimination (Drug A): Bupropion is extensively metabolized in humans. Oxidation of the bupropion side chain results in the formation of a glycine conjugate of metachlorobenzoic acid, which is then excreted as the major urinary metabolite. Following oral administration of 200 mg of 14C-bupropion in humans, 87% and 10% of the radioactive dose were recovered in the urine and feces, respectively. However, the fraction of the oral dose of bupropion excreted unchanged was only 0.5%, a finding consistent with the extensive metabolism of bupropion. •Route of elimination (Drug B): Olsalazine and its metabolites are excreted in the urine. Total recovery of oral 14C-labeled olsalazine in animals and humans ranges from 90 to 97%. Approximately 20% of the total mesalamine is recovered in the urine. Of the total mesalamine found in the urine, more than 90% is N-acetyl-5-ASA. Only small amounts of mesalamine are detected in the urine. The remaining mesalamine is partially acetylated and excreted in the feces. From fecal dialysis, the concentration of mesalamine in the colon following olsalazine has been calculated to be 18 to 49 mmol/L. The urinary recovery of olsalazine is below 1%. Less than 5% of an oral dose (0.25 to 2g) was recovered unchanged in the feces; however, more than 50% of the oral dose was excreted in feces as unchanged olsalazine when the whole gut transit time was decreased by approximately 50%. •Half-life (Drug A): 24 hours •Half-life (Drug B): Olsalazine has a very short serum half-life, approximately 0.9 hours. Olsalazine-S has a half-life of seven days due to slow dissociation from the protein binding site. •Clearance (Drug A): No clearance available •Clearance (Drug B): No clearance available •Toxicity (Drug A): Symptoms of overdose include seizures, hallucinations, loss of consciousness, tachycardia, and cardiac arrest. •Toxicity (Drug B): There is no information available regarding acute toxicity (LD 50 ) of olsalazine. Symptoms of salicylate toxicity include nausea, vomiting and abdominal pain, tachypnea, hyperpnea, tinnitus, and neurologic symptoms (headache, dizziness, confusion, seizures). Severe intoxication may lead to electrolyte and blood pH imbalance and potentially to organ damage. There is no antidote for olsalazine overdose; however, conventional therapy for salicylate toxicity, such as gastrointestinal tract decontamination, may be beneficial in acute overdosage. Overdose should be managed with proper medical care and appropriate supportive care, including the possible use of emesis, cathartics, and activated charcoal to prevent further absorption. Fluid and electrolyte imbalance may be managed with appropriate intravenous therapy and maintenance of adequate renal function. •Brand Names (Drug A): Aplenzin, Auvelity, Budeprion, Contrave, Forfivo, Wellbutrin, Zyban •Brand Names (Drug B): Dipentum •Synonyms (Drug A): No synonyms listed •Synonyms (Drug B): No synonyms listed •Summary (Drug A): Bupropion is a norepinephrine and dopamine reuptake inhibitor used in the treatment of major depressive disorder (MDD), seasonal affective disorder (SAD), and as an aid to smoking cessation. •Summary (Drug B): Olsalazine is an anti-inflammatory aminosalicylate used in the treatment of inflammatory bowel disease and ulcerative colitis.

The subject drug is a nephrotoxic agent that may potentially impair renal function and decrease the excretion of drugs that mainly undergo renal excretion as the principal mode of clearance, such as the affected drug. Attenuated renal excretion of the affected drug may increase drug concentrations, leading to an elevated risk for drug-related adverse effects. The severity of the interaction is minor.

Question: Does Bupropion and Olsalazine interact? Information: •Drug A: Bupropion •Drug B: Olsalazine •Severity: MINOR •Description: Olsalazine may decrease the excretion rate of Bupropion which could result in a higher serum level. •Extended Description: The subject drug is a nephrotoxic agent that may potentially impair renal function and decrease the excretion of drugs that mainly undergo renal excretion as the principal mode of clearance, such as the affected drug. Attenuated renal excretion of the affected drug may increase drug concentrations, leading to an elevated risk for drug-related adverse effects. •Indication (Drug A): Bupropion is indicated for the treatment of major depressive disorder (MDD), seasonal affective disorder (SAD), and as an aid to smoking cessation. When used in combination with naltrexone as the marketed product ContraveⓇ, bupropion is indicated as an adjunct to a reduced-calorie diet and increased physical activity for chronic weight management in adults with an initial body mass index (BMI) of: 30 kg/m^2 or greater (obese) or 27 kg/m^2 or greater (overweight) in the presence of at least one weight-related comorbid condition (e.g., hypertension, type 2 diabetes mellitus, or dyslipidemia). Bupropion is also used off-label as a first-line treatment in patients with ADHD and comorbid bipolar disorder when used as an adjunct to mood stabilizers. •Indication (Drug B): In the US, olsalazine is indicated for the maintenance of remission of ulcerative colitis in adult patients who are intolerant to sulfasalazine. In Canada, it is used in the treatment of acute ulcerative colitis of mild to moderate severity, with or without the concomitant use of steroids. It is also indicated for the long-term maintenance of patients with ulcerative colitis in remission. •Pharmacodynamics (Drug A): Bupropion is chemically unrelated to tricyclic, tetracyclic, selective serotonin re-uptake inhibitors, or other known antidepressant agents. Compared to classical tricyclic antidepressants, Bupropion is a relatively weak inhibitor of the neuronal uptake of norepinephrine and dopamine. In addition, Bupropion does not inhibit monoamine oxidase. Bupropion has been found to be essentially inactive at the serotonin transporter (SERT)(IC50 >10 000 nM), however both bupropion and its primary metabolite hydroxybupropion have been found to block the function of cation-selective serotonin type 3A receptors (5-HT3ARs). Bupropion produces dose-related central nervous system (CNS) stimulant effects in animals, as evidenced by increased locomotor activity, increased rates of responding in various schedule-controlled operant behaviour tasks, and, at high doses, induction of mild stereotyped behaviour. Due to these stimulant effects and selective activity at dopamine and norepinephrine receptors, bupropion has been identified as having an abuse potential. Bupropion has a similar structure to the controlled substance Cathinone, and has been identified as having mild amphetamine-like activity, particularly when inhaled or injected. Bupropion is also known to lower the seizure threshold, making any pre-existing seizure conditions a contraindication to its use. This risk is exacerbated when bupropion is combined with other drugs or substances that lower the seizure threshold, such as cocaine, or in clinical situations that would increase the risk of a seizure such as abrupt alcohol or benzodiazepine withdrawal. As norepinephrine has been shown to have anticonvulsant properties, bupropion's inhibitory effects on NET are thought to contribute to its pro-convulsant activity. Bupropion has been shown to increase blood pressure and pose a risk for exacerbation of unmanaged or pre-existing hypertension, however, clinical trials of bupropion in smokers with CVD have not identified an increased incidence of CV events including stroke or heart attack. In clinical trials, the mean increase in systolic blood pressure associated with the use of bupropion was found to be 1.3 mmHg. •Pharmacodynamics (Drug B): Olsalazine is an anti-inflammatory agent that blocks the production of cyclooxygenase (COX)-derived products of arachidonic acid metabolism. It works to alleviate inflammation in ulcerative colitis. Olsalazine was shown to decrease water and sodium absorption. While olsalazine is not expected to affect the motility and transit time of small intestines, it decreased small bowel transit time at high doses ranging from 60 to 120 mg/kg. In about 40% of the patients with ulcerative colitis, administration of olsalazine 1g daily was associated with a decrease in whole gut transit time. •Mechanism of action (Drug A): Bupropion is a norepinephrine/dopamine-reuptake inhibitor (NDRI) that exerts its pharmacological effects by weakly inhibiting the enzymes involved in the uptake of the neurotransmitters norepinephrine and dopamine from the synaptic cleft, therefore prolonging their duration of action within the neuronal synapse and the downstream effects of these neurotransmitters. More specifically, bupropion binds to the norepinephrine transporter (NET) and the dopamine transporter (DAT). Bupropion was originally classified as an "atypical" antidepressant because it does not exert the same effects as the classical antidepressants such as Monoamine Oxidase Inhibitors (MAOIs), Tricyclic Antidepressants (TCAs), or Selective Serotonin Reuptake Inhibitors (SSRIs). While it has comparable effectiveness to typical first-line options for the treatment of depression such as SSRIs, bupropion is a unique option for the treatment of MDD as it lacks any clinically relevant serotonergic effects, typical of other mood medications, or any effects on histamine or adrenaline receptors. Lack of activity at these receptors results in a more tolerable side effect profile; bupropion is less likely to cause sexual side effects, sedation, or weight gain as compared to SSRIs or TCAs, for example. When used as an aid to smoking cessation, bupropion is thought to confer its anti-craving and anti-withdrawal effects by inhibiting dopamine reuptake, which is thought to be involved in the reward pathways associated with nicotine, and through the antagonism of the nicotinic acetylcholinergic receptor (AChR), thereby blunting the effects of nicotine. Furthermore, the stimulatory effects produced by bupropion in the central nervous system are similar to nicotine's effects, making low doses of bupropion a suitable option as a nicotine substitute. When used in combination with naltrexone in the marketed product ContraveⓇ for chronic weight management, the two components are thought to have effects on areas of the brain involved in the regulation of food intake. This includes the hypothalamus, which is involved in appetite regulation, and the mesolimbic dopamine circuit, which is involved in reward pathways. Studies have shown that the combined activity of bupropion and naltrexone increase the firing rate of hypothalamic pro-opiomelanocortin (POMC) neurons and blockade of opioid receptor-mediated POMC auto-inhibition, which are associated with a reduction in food intake and increased energy expenditure. This combination was also found to reduce food intake when injected directly into the ventral tegmental area of the mesolimbic circuit in mice, which is an area associated with the regulation of reward pathways. •Mechanism of action (Drug B): Upon administration, the azo bond connecting two molecules of mesalamine (also known as 5-aminosalicylic acid or 5-ASA) is cleaved by azoreductase-containing bacteria in the colon. The two molecules of mesalamine are released to mediate therapeutic effects. The exact mechanism of action of olsalazine and its active moiety mesalamine in ulcerative colitis has not been elucidated; however, it is understood that mesalamine mediates an anti-inflammatory action on epithelial cells of the colon. The COX-derived (i.e., prostanoids such as prostaglandin E2) and lipoxygenase-derived products (i.e., leukotrienes [LTs] and hydroxyeicosatetraenoic acids [HETEs]) of arachidonic acid metabolism have been implicated in the pathogenesis and maintenance of inflammatory disorders, including ulcerative colitis and inflammatory bowel disease. Mesalamine may attenuate inflammation by blocking the COX enzyme and inhibiting prostaglandin production in the colon. Olsalazine was also shown to inhibit xanthine oxidase, an enzyme that generates oxygen-derived free radicals. Olsalazine may attenuate intestinal inflammation by limiting macrophage migration to inflamed intestinal mucosa: it was shown to inhibit in vitro migration of intestinal macrophages in response to leukotriene B 4. Olsalazine may also act as a free radical scavenger, and mesalazine may suppress fatty acid peroxidation. •Absorption (Drug A): Bupropion is currently available in 3 distinct, but bioequivalent formulations: immediate release (IR), sustained-release (SR), and extended-release (XL). Immediate Release Formulation In humans, following oral administration of bupropion hydrochloride tablets, peak plasma bupropion concentrations are usually achieved within 2 hours. IR formulations provide a short duration of action and are therefore generally dosed three times per day. Sustained Release Formulation In humans, following oral administration of bupropion hydrochloride sustained-release tablets (SR), peak plasma concentration (Cmax) of bupropion is usually achieved within 3 hours. SR formulations provide a 12-hour extended release of medication and are therefore generally dosed twice per day. Extended Release Formulation Following single oral administration of bupropion hydrochloride extended-release tablets (XL) to healthy volunteers, the median time to peak plasma concentrations for bupropion was approximately 5 hours. The presence of food did not affect the peak concentration or area under the curve of bupropion. XL formulations provide a 24-hour extended release of medication and are therefore generally dosed once per day/ In a trial comparing chronic dosing with bupropion hydrochloride extended-release tablets (SR) 150 mg twice daily to bupropion immediate-release formulation 100 mg 3 times daily, the steady state Cmax for bupropion after bupropion hydrochloride sustained-release tablets (SR) administration was approximately 85% of those achieved after bupropion immediate-release formulation administration. Exposure (AUC) to bupropion was equivalent for both formulations. Bioequivalence was also demonstrated for all three major active metabolites (i.e., hydroxybupropion, threohydrobupropion and erythrohydrobupropion) for both Cmax and AUC. Thus, at steady state, bupropion hydrochloride sustained-release tablets (SR) given twice daily, and the immediate-release formulation of bupropion given 3 times daily, are essentially bioequivalent for both bupropion and the 3 quantitatively important metabolites. Furthermore, in a study comparing 14-day dosing with bupropion hydrochloride extended-release tablets (XL), 300 mg once-daily to the immediate-release formulation of bupropion at 100 mg 3 times daily, equivalence was demonstrated for peak plasma concentration and area under the curve for bupropion and the three metabolites (hydroxybupropion, threohydrobupropion, and erythrohydrobupropion). Additionally, in a study comparing 14-day dosing with bupropion hydrochloride extended-release tablets (XL) 300 mg once daily to the sustained-release formulation of bupropion at 150 mg 2 times daily, equivalence was demonstrated for peak plasma concentration and area under the curve for bupropion and the three metabolites. Bupropion hydrochloride extended-release tablets (SR) can be taken with or without food. Bupropion Cmax and AUC were increased by 11% to 35% and 16% to 19%, respectively, when bupropion hydrochloride extended-release tablets (SR) was administered with food to healthy volunteers in three trials. The food effect is not considered clinically significant. Following a single-dose administration of bupropion hydrochloride extended-release tablets (SR) in humans, Cmax of bupropion's metabolite hydroxybupropion occurs approximately 6 hours post-dose and is approximately 10 times the peak level of the parent drug at steady state. The elimination half-life of hydroxybupropion is approximately 20 (±5) hours and its AUC at steady state is about 17 times that of bupropion. The times to peak concentrations for the erythrohydrobupropion and threohydrobupropion metabolites are similar to that of the hydroxybupropion metabolite. However, their elimination half-lives are longer, 33(±10) and 37 (±13) hours, respectively, and steady-state AUCs are 1.5 and 7 times that of bupropion, respectively. •Absorption (Drug B): After oral administration, olsalazine has limited systemic bioavailability, with less than 5% of the oral dose being absorbed. Based on oral and intravenous dosing studies, approximately 2.4% of a single 1 g oral dose is absorbed. Maximum serum concentrations of olsalazine appear after approximately one hour and, even after a 1 g single dose, are low (e.g., 1.6 to 6.2 µmol/L). Patients on daily doses of 1 g olsalazine for two to four years show a stable plasma concentration of olsalazine-S (3.3 to 12.4 µmol/L). Olsalazine-S accumulates to a steady state within two to three weeks. Serum concentrations of mesalamine are detected after four to eight hours. The peak levels of mesalamine after an oral dose of 1 g olsalazine are low (i.e., 0 to 4.3 µmol/L). •Volume of distribution (Drug A): No volume of distribution available •Volume of distribution (Drug B): The steady-state volume of distribution determined in healthy volunteers is approximately 5L. •Protein binding (Drug A): In vitro tests show that bupropion is 84% bound to human plasma proteins at concentrations up to 200 mcg per mL. The extent of protein binding of the hydroxybupropion metabolite is similar to that for bupropion, whereas the extent of protein binding of the threohydrobupropion metabolite is about half that seen with bupropion. •Protein binding (Drug B): Olsalazine and its metabolite olsalazine-S, are more than 99% bound to plasma proteins. Less than 1% of both olsalazine and olsalazine-S appears undissociated in plasma. It does not interfere with the protein binding of warfarin. Mesalamine (5-aminosalicylic acid, 5-ASA) and its metabolite, N-acetyl-5-ASA, are 74 and 81%, respectively, bound to plasma proteins. •Metabolism (Drug A): Bupropion is extensively metabolized in humans. Three metabolites are active: hydroxybupropion, which is formed via hydroxylation of the tert-butyl group of bupropion, and the amino-alcohol isomers, threohydrobupropion and erythrohydrobupropion, which are formed via reduction of the carbonyl group. In vitro findings suggest that CYP2B6 is the principal isoenzyme involved in the formation of hydroxybupropion, while cytochrome P450 enzymes are not involved in the formation of threohydrobupropion. Hydroxybupropion has been shown to have the same affinity as bupropion for the norepinephrine transporter (NET) but approximately 50% of its antidepressant activity despite reaching concentrations of ~10-fold higher than that of the parent drug. Oxidation of the bupropion side chain results in the formation of a glycine conjugate of meta-chlorobenzoic acid, which is then excreted as the major urinary metabolite. The potency and toxicity of the metabolites relative to bupropion have not been fully characterized. However, it has been demonstrated in an antidepressant screening test in mice that hydroxybupropion is one-half as potent as bupropion, while threohydrobupropion and erythrohydrobupropion are 5-fold less potent than bupropion. This may be of clinical importance because the plasma concentrations of the metabolites are as high as or higher than those of bupropion. Bupropion and its metabolites exhibit linear kinetics following chronic administration of 300 to 450 mg per day. •Metabolism (Drug B): Olsalazine is cleaved by colonic bacteria to release its active ingredient, mesalamine. Mesalamine can undergo acetylation to form N-acetyl-5-aminosalicylic acid (N-acetyl-5-ASA, Ac-5-ASA) by the colonic epithelium; however, the extent of acetylation depends on transit time. Approximately 0.1% of an oral dose of olsalazine is metabolized in the liver to olsalazine-O-sulfate (olsalazine-S). •Route of elimination (Drug A): Bupropion is extensively metabolized in humans. Oxidation of the bupropion side chain results in the formation of a glycine conjugate of metachlorobenzoic acid, which is then excreted as the major urinary metabolite. Following oral administration of 200 mg of 14C-bupropion in humans, 87% and 10% of the radioactive dose were recovered in the urine and feces, respectively. However, the fraction of the oral dose of bupropion excreted unchanged was only 0.5%, a finding consistent with the extensive metabolism of bupropion. •Route of elimination (Drug B): Olsalazine and its metabolites are excreted in the urine. Total recovery of oral 14C-labeled olsalazine in animals and humans ranges from 90 to 97%. Approximately 20% of the total mesalamine is recovered in the urine. Of the total mesalamine found in the urine, more than 90% is N-acetyl-5-ASA. Only small amounts of mesalamine are detected in the urine. The remaining mesalamine is partially acetylated and excreted in the feces. From fecal dialysis, the concentration of mesalamine in the colon following olsalazine has been calculated to be 18 to 49 mmol/L. The urinary recovery of olsalazine is below 1%. Less than 5% of an oral dose (0.25 to 2g) was recovered unchanged in the feces; however, more than 50% of the oral dose was excreted in feces as unchanged olsalazine when the whole gut transit time was decreased by approximately 50%. •Half-life (Drug A): 24 hours •Half-life (Drug B): Olsalazine has a very short serum half-life, approximately 0.9 hours. Olsalazine-S has a half-life of seven days due to slow dissociation from the protein binding site. •Clearance (Drug A): No clearance available •Clearance (Drug B): No clearance available •Toxicity (Drug A): Symptoms of overdose include seizures, hallucinations, loss of consciousness, tachycardia, and cardiac arrest. •Toxicity (Drug B): There is no information available regarding acute toxicity (LD 50 ) of olsalazine. Symptoms of salicylate toxicity include nausea, vomiting and abdominal pain, tachypnea, hyperpnea, tinnitus, and neurologic symptoms (headache, dizziness, confusion, seizures). Severe intoxication may lead to electrolyte and blood pH imbalance and potentially to organ damage. There is no antidote for olsalazine overdose; however, conventional therapy for salicylate toxicity, such as gastrointestinal tract decontamination, may be beneficial in acute overdosage. Overdose should be managed with proper medical care and appropriate supportive care, including the possible use of emesis, cathartics, and activated charcoal to prevent further absorption. Fluid and electrolyte imbalance may be managed with appropriate intravenous therapy and maintenance of adequate renal function. •Brand Names (Drug A): Aplenzin, Auvelity, Budeprion, Contrave, Forfivo, Wellbutrin, Zyban •Brand Names (Drug B): Dipentum •Synonyms (Drug A): No synonyms listed •Synonyms (Drug B): No synonyms listed •Summary (Drug A): Bupropion is a norepinephrine and dopamine reuptake inhibitor used in the treatment of major depressive disorder (MDD), seasonal affective disorder (SAD), and as an aid to smoking cessation. •Summary (Drug B): Olsalazine is an anti-inflammatory aminosalicylate used in the treatment of inflammatory bowel disease and ulcerative colitis. Output: The subject drug is a nephrotoxic agent that may potentially impair renal function and decrease the excretion of drugs that mainly undergo renal excretion as the principal mode of clearance, such as the affected drug. Attenuated renal excretion of the affected drug may increase drug concentrations, leading to an elevated risk for drug-related adverse effects. The severity of the interaction is minor.

Does Bupropion and Ondansetron interact?

•Drug A: Bupropion •Drug B: Ondansetron •Severity: MAJOR •Description: The metabolism of Ondansetron can be decreased when combined with Bupropion. •Extended Description: The subject drug is a strong CYP2D6 inhibitor and the affected drug is metabolized by CYP2D6. Concomitant administration may decrease the metabolism of the affected drug, which could increase serum concentrations as well as the risk and severity of adverse effects. •Indication (Drug A): Bupropion is indicated for the treatment of major depressive disorder (MDD), seasonal affective disorder (SAD), and as an aid to smoking cessation. When used in combination with naltrexone as the marketed product ContraveⓇ, bupropion is indicated as an adjunct to a reduced-calorie diet and increased physical activity for chronic weight management in adults with an initial body mass index (BMI) of: 30 kg/m^2 or greater (obese) or 27 kg/m^2 or greater (overweight) in the presence of at least one weight-related comorbid condition (e.g., hypertension, type 2 diabetes mellitus, or dyslipidemia). Bupropion is also used off-label as a first-line treatment in patients with ADHD and comorbid bipolar disorder when used as an adjunct to mood stabilizers. •Indication (Drug B): In the adult patient population: i) orally administered ondansetron tablets and orally disintegrating tablets (ODT) are indicated for: - the prevention of nausea and vomiting associated with emetogenic cancer chemotherapy, including high dose (ie. greater than or equal to 50 mg/m2) cisplatin therapy, and radiotherapy, and - the prevention and treatment of postoperative nausea and vomiting ii) intravenously administered ondansetron injection formulations are indicated for: - the prevention of nausea and vomiting associated with emetogenic cancer chemotherapy, including high dose (ie. greater than or equal to 50 mg/m2) cisplatin therapy, and - the prevention and treatment of postoperative nausea and vomiting In the pediatric (4-18 years of age) patient population: i) ondansetron was effective and well tolerated when given to children 4-12 years of age for the treatment of post-chemotherapy induced nausea and vomiting, ii) ondansetron tablets, ondansetron ODT, ondansetron injection are not indicated for the treatment of children 3 years of age or younger, iii) ondansetron tablets, ondansetron ODT, ondansetron injection are not indicated for use in any age group of the pediatric population for the treatment of post-radiotherapy induced nausea and vomiting, and iV) ondansetron tablets, ondansetron ODT, ondansetron injection are not indicated for use in any age group of the pediatric population for the treatment of postoperative nausea and vomiting In the geriatric (>65 years of age) patient population: i) efficacy and tolerance of ondansetron were similar to that observed in younger adults for the treatment of post-chemotherapy and radiotherapy-induced nausea and vomiting, and ii) clinical experience in the use of ondansetron in the prevention and treatment of postoperative nausea and vomiting is limited and is not indicated for use in the geriatric patient population •Pharmacodynamics (Drug A): Bupropion is chemically unrelated to tricyclic, tetracyclic, selective serotonin re-uptake inhibitors, or other known antidepressant agents. Compared to classical tricyclic antidepressants, Bupropion is a relatively weak inhibitor of the neuronal uptake of norepinephrine and dopamine. In addition, Bupropion does not inhibit monoamine oxidase. Bupropion has been found to be essentially inactive at the serotonin transporter (SERT)(IC50 >10 000 nM), however both bupropion and its primary metabolite hydroxybupropion have been found to block the function of cation-selective serotonin type 3A receptors (5-HT3ARs). Bupropion produces dose-related central nervous system (CNS) stimulant effects in animals, as evidenced by increased locomotor activity, increased rates of responding in various schedule-controlled operant behaviour tasks, and, at high doses, induction of mild stereotyped behaviour. Due to these stimulant effects and selective activity at dopamine and norepinephrine receptors, bupropion has been identified as having an abuse potential. Bupropion has a similar structure to the controlled substance Cathinone, and has been identified as having mild amphetamine-like activity, particularly when inhaled or injected. Bupropion is also known to lower the seizure threshold, making any pre-existing seizure conditions a contraindication to its use. This risk is exacerbated when bupropion is combined with other drugs or substances that lower the seizure threshold, such as cocaine, or in clinical situations that would increase the risk of a seizure such as abrupt alcohol or benzodiazepine withdrawal. As norepinephrine has been shown to have anticonvulsant properties, bupropion's inhibitory effects on NET are thought to contribute to its pro-convulsant activity. Bupropion has been shown to increase blood pressure and pose a risk for exacerbation of unmanaged or pre-existing hypertension, however, clinical trials of bupropion in smokers with CVD have not identified an increased incidence of CV events including stroke or heart attack. In clinical trials, the mean increase in systolic blood pressure associated with the use of bupropion was found to be 1.3 mmHg. •Pharmacodynamics (Drug B): Ondansetron is a highly specific and selective serotonin 5-HT 3 receptor antagonist, not shown to have activity at other known serotonin receptors and with low affinity for dopamine receptors,. The serotonin 5-HT 3 receptors are located on the nerve terminals of the vagus in the periphery, and centrally in the chemoreceptor trigger zone of the area postrema,. The temporal relationship between the emetogenic action of emetogenic drugs and the release of serotonin, as well as the efficacy of antiemetic agents, suggest that chemotherapeutic agents release serotonin from the enterochromaffin cells of the small intestine by causing degenerative changes in the GI tract,. The serotonin then stimulates the vagal and splanchnic nerve receptors that project to the medullary vomiting center, as well as the 5-HT 3 receptors in the area postrema, thus initiating the vomiting reflex, causing nausea and vomiting,. Moreover, the effect of ondansetron on the QTc interval was evaluated in a double-blind, randomized, placebo and positive (moxifloxacin) controlled, crossover study in 58 healthy adult men and women. Ondansetron was tested at single doses of 8 mg and 32 mg infused intravenously over 15 minutes. At the highest tested dose of 32 mg, prolongation of the Fridericia-corrected QTc interval (QT/RR0.33=QTcF) was observed from 15 min to 4 h after the start of the 15 min infusion, with a maximum mean (upper limit of 90% CI) difference in QTcF from placebo after baseline-correction of 19.6 (21.5) msec at 20 min. At the lower tested dose of 8 mg, QTc prolongation was observed from 15 min to 1 h after the start of the 15-minute infusion, with a maximum mean (upper limit of 90% CI) difference in QTcF from placebo after baseline-correction of 5.8 (7.8) msec at 15 min. The magnitude of QTc prolongation with ondansetron is expected to be greater if the infusion rate is faster than 15 minutes. The 32 mg intravenous dose of ondansetron must not be administered. No treatment-related effects on the QRS duration or the PR interval were observed at either the 8 or 32 mg dose. An ECG assessment study has not been performed for orally administered ondansetron. On the basis of pharmacokinetic-pharmacodynamic modelling, an 8 mg oral dose of ondansetron is predicted to cause a mean QTcF increase of 0.7 ms (90% CI -2.1, 3.3) at steady-state, assuming a mean maximal plasma concentration of 24.7 ng/mL (95% CI 21.1, 29.0). The magnitude of QTc prolongation at the recommended 5 mg/m2 dose in pediatrics has not been studied, but pharmacokinetic-pharmacodynamic modeling predicts a mean increase of 6.6 ms (90% CI 2.8, 10.7) at maximal plasma concentrations. In healthy subjects, single intravenous doses of 0.15 mg/kg of ondansetron had no effect on esophageal motility, gastric motility, lower esophageal sphincter pressure, or small intestinal transit time. Multiday administration of ondansetron has been shown to slow colonic transit in healthy subjects. Ondansetron has no effect on plasma prolactin concentrations. •Mechanism of action (Drug A): Bupropion is a norepinephrine/dopamine-reuptake inhibitor (NDRI) that exerts its pharmacological effects by weakly inhibiting the enzymes involved in the uptake of the neurotransmitters norepinephrine and dopamine from the synaptic cleft, therefore prolonging their duration of action within the neuronal synapse and the downstream effects of these neurotransmitters. More specifically, bupropion binds to the norepinephrine transporter (NET) and the dopamine transporter (DAT). Bupropion was originally classified as an "atypical" antidepressant because it does not exert the same effects as the classical antidepressants such as Monoamine Oxidase Inhibitors (MAOIs), Tricyclic Antidepressants (TCAs), or Selective Serotonin Reuptake Inhibitors (SSRIs). While it has comparable effectiveness to typical first-line options for the treatment of depression such as SSRIs, bupropion is a unique option for the treatment of MDD as it lacks any clinically relevant serotonergic effects, typical of other mood medications, or any effects on histamine or adrenaline receptors. Lack of activity at these receptors results in a more tolerable side effect profile; bupropion is less likely to cause sexual side effects, sedation, or weight gain as compared to SSRIs or TCAs, for example. When used as an aid to smoking cessation, bupropion is thought to confer its anti-craving and anti-withdrawal effects by inhibiting dopamine reuptake, which is thought to be involved in the reward pathways associated with nicotine, and through the antagonism of the nicotinic acetylcholinergic receptor (AChR), thereby blunting the effects of nicotine. Furthermore, the stimulatory effects produced by bupropion in the central nervous system are similar to nicotine's effects, making low doses of bupropion a suitable option as a nicotine substitute. When used in combination with naltrexone in the marketed product ContraveⓇ for chronic weight management, the two components are thought to have effects on areas of the brain involved in the regulation of food intake. This includes the hypothalamus, which is involved in appetite regulation, and the mesolimbic dopamine circuit, which is involved in reward pathways. Studies have shown that the combined activity of bupropion and naltrexone increase the firing rate of hypothalamic pro-opiomelanocortin (POMC) neurons and blockade of opioid receptor-mediated POMC auto-inhibition, which are associated with a reduction in food intake and increased energy expenditure. This combination was also found to reduce food intake when injected directly into the ventral tegmental area of the mesolimbic circuit in mice, which is an area associated with the regulation of reward pathways. •Mechanism of action (Drug B): Ondansetron is a selective antagonist of the serotonin receptor subtype, 5-HT3. Cytotoxic chemotherapy and radiotherapy are associated with the release of serotonin (5-HT) from enterochromaffin cells of the small intestine, presumably initiating a vomiting reflex through stimulation of 5-HT3 receptors located on vagal afferents. Ondansetron may block the initiation of this reflex. Activation of vagal afferents may also cause a central release of serotonin from the chemoreceptor trigger zone of the area postrema, located on the floor of the fourth ventricle. Thus, the antiemetic effect of ondansetron is probably due to the selective antagonism of 5-HT3 receptors on neurons located in either the peripheral or central nervous systems, or both. Although the mechanisms of action of ondansetron in treating postoperative nausea and vomiting and cytotoxic induced nausea and vomiting may share similar pathways, the role of ondansetron in opiate-induced emesis has not yet been formally established. •Absorption (Drug A): Bupropion is currently available in 3 distinct, but bioequivalent formulations: immediate release (IR), sustained-release (SR), and extended-release (XL). Immediate Release Formulation In humans, following oral administration of bupropion hydrochloride tablets, peak plasma bupropion concentrations are usually achieved within 2 hours. IR formulations provide a short duration of action and are therefore generally dosed three times per day. Sustained Release Formulation In humans, following oral administration of bupropion hydrochloride sustained-release tablets (SR), peak plasma concentration (Cmax) of bupropion is usually achieved within 3 hours. SR formulations provide a 12-hour extended release of medication and are therefore generally dosed twice per day. Extended Release Formulation Following single oral administration of bupropion hydrochloride extended-release tablets (XL) to healthy volunteers, the median time to peak plasma concentrations for bupropion was approximately 5 hours. The presence of food did not affect the peak concentration or area under the curve of bupropion. XL formulations provide a 24-hour extended release of medication and are therefore generally dosed once per day/ In a trial comparing chronic dosing with bupropion hydrochloride extended-release tablets (SR) 150 mg twice daily to bupropion immediate-release formulation 100 mg 3 times daily, the steady state Cmax for bupropion after bupropion hydrochloride sustained-release tablets (SR) administration was approximately 85% of those achieved after bupropion immediate-release formulation administration. Exposure (AUC) to bupropion was equivalent for both formulations. Bioequivalence was also demonstrated for all three major active metabolites (i.e., hydroxybupropion, threohydrobupropion and erythrohydrobupropion) for both Cmax and AUC. Thus, at steady state, bupropion hydrochloride sustained-release tablets (SR) given twice daily, and the immediate-release formulation of bupropion given 3 times daily, are essentially bioequivalent for both bupropion and the 3 quantitatively important metabolites. Furthermore, in a study comparing 14-day dosing with bupropion hydrochloride extended-release tablets (XL), 300 mg once-daily to the immediate-release formulation of bupropion at 100 mg 3 times daily, equivalence was demonstrated for peak plasma concentration and area under the curve for bupropion and the three metabolites (hydroxybupropion, threohydrobupropion, and erythrohydrobupropion). Additionally, in a study comparing 14-day dosing with bupropion hydrochloride extended-release tablets (XL) 300 mg once daily to the sustained-release formulation of bupropion at 150 mg 2 times daily, equivalence was demonstrated for peak plasma concentration and area under the curve for bupropion and the three metabolites. Bupropion hydrochloride extended-release tablets (SR) can be taken with or without food. Bupropion Cmax and AUC were increased by 11% to 35% and 16% to 19%, respectively, when bupropion hydrochloride extended-release tablets (SR) was administered with food to healthy volunteers in three trials. The food effect is not considered clinically significant. Following a single-dose administration of bupropion hydrochloride extended-release tablets (SR) in humans, Cmax of bupropion's metabolite hydroxybupropion occurs approximately 6 hours post-dose and is approximately 10 times the peak level of the parent drug at steady state. The elimination half-life of hydroxybupropion is approximately 20 (±5) hours and its AUC at steady state is about 17 times that of bupropion. The times to peak concentrations for the erythrohydrobupropion and threohydrobupropion metabolites are similar to that of the hydroxybupropion metabolite. However, their elimination half-lives are longer, 33(±10) and 37 (±13) hours, respectively, and steady-state AUCs are 1.5 and 7 times that of bupropion, respectively. •Absorption (Drug B): Ondansetron is absorbed from the gastrointestinal tract and undergoes some limited first-pass metabolism. Mean bioavailability in healthy subjects, following administration of a single 8-mg tablet, was recorded as being approximately 56% to 60%. Bioavailability is also slightly enhanced by the presence of food. Ondansetron systemic exposure does not increase proportionately to dose. The AUC from a 16-mg tablet was 24% greater than predicted from an 8-mg tablet dose. This may reflect some reduction of first-pass metabolism at higher oral doses. •Volume of distribution (Drug A): No volume of distribution available •Volume of distribution (Drug B): The volume of distribution of ondansetron has been recorded as being approximately 160L. •Protein binding (Drug A): In vitro tests show that bupropion is 84% bound to human plasma proteins at concentrations up to 200 mcg per mL. The extent of protein binding of the hydroxybupropion metabolite is similar to that for bupropion, whereas the extent of protein binding of the threohydrobupropion metabolite is about half that seen with bupropion. •Protein binding (Drug B): The plasma protein binding associated with ondansetron was documented as approximately 73%. •Metabolism (Drug A): Bupropion is extensively metabolized in humans. Three metabolites are active: hydroxybupropion, which is formed via hydroxylation of the tert-butyl group of bupropion, and the amino-alcohol isomers, threohydrobupropion and erythrohydrobupropion, which are formed via reduction of the carbonyl group. In vitro findings suggest that CYP2B6 is the principal isoenzyme involved in the formation of hydroxybupropion, while cytochrome P450 enzymes are not involved in the formation of threohydrobupropion. Hydroxybupropion has been shown to have the same affinity as bupropion for the norepinephrine transporter (NET) but approximately 50% of its antidepressant activity despite reaching concentrations of ~10-fold higher than that of the parent drug. Oxidation of the bupropion side chain results in the formation of a glycine conjugate of meta-chlorobenzoic acid, which is then excreted as the major urinary metabolite. The potency and toxicity of the metabolites relative to bupropion have not been fully characterized. However, it has been demonstrated in an antidepressant screening test in mice that hydroxybupropion is one-half as potent as bupropion, while threohydrobupropion and erythrohydrobupropion are 5-fold less potent than bupropion. This may be of clinical importance because the plasma concentrations of the metabolites are as high as or higher than those of bupropion. Bupropion and its metabolites exhibit linear kinetics following chronic administration of 300 to 450 mg per day. •Metabolism (Drug B): In vitro metabolism studies have shown that ondansetron is a substrate for human hepatic cytochrome P450 enzymes, including CYP1A2, CYP2D6 and CYP3A4. In terms of overall ondansetron turnover, CYP3A4 played the predominant role. Because of the multiplicity of metabolic enzymes capable of metabolizing ondansetron, it is likely that inhibition or loss of one enzyme (e.g. CYP2D6 enzyme deficiency) will be compensated by others and may result in little change in overall rates of ondansetron clearance. Following oral or IV administration, ondansetron is extensively metabolised and excreted in the urine and faeces. In humans, less than 10% of the dose is excreted unchanged in the urine. The major urinary metabolites are glucuronide conjugates (45%), sulphate conjugates (20%) and hydroxylation products (10%). The primary metabolic pathway is subsequently hydroxylation on the indole ring followed by subsequent glucuronide or sulfate conjugation. Although some nonconjugated metabolites have pharmacologic activity, these are not found in plasma at concentrations likely to significantly contribute to the biological activity of ondansetron. •Route of elimination (Drug A): Bupropion is extensively metabolized in humans. Oxidation of the bupropion side chain results in the formation of a glycine conjugate of metachlorobenzoic acid, which is then excreted as the major urinary metabolite. Following oral administration of 200 mg of 14C-bupropion in humans, 87% and 10% of the radioactive dose were recovered in the urine and feces, respectively. However, the fraction of the oral dose of bupropion excreted unchanged was only 0.5%, a finding consistent with the extensive metabolism of bupropion. •Route of elimination (Drug B): Following oral or IV administration, ondansetron is extensively metabolised and excreted in the urine and faeces. •Half-life (Drug A): 24 hours •Half-life (Drug B): The half-life of ondansetron after either an 8 mg oral dose or intravenous dose was approximately 3-4 hours and could be extended to 6-8 hours in the elderly. •Clearance (Drug A): No clearance available •Clearance (Drug B): The clearance values determined for ondansetron in various patient age groups were recorded as approximately 0.38 L/h/kg in normal adult volunteers aged 19-40 yrs, 0.32 L/h/kg in normal adult volunteers aged 61-74 yrs, 0.26 L/h/kg in normal adult volunteers aged >=75 yrs. •Toxicity (Drug A): Symptoms of overdose include seizures, hallucinations, loss of consciousness, tachycardia, and cardiac arrest. •Toxicity (Drug B): At present, there is little information concerning overdosage with ondansetron. Nevertheless, there have been certain cases of somewhat idiosyncratic adverse effects associated with particular dosages of ondansetron used. “Sudden blindness” (amaurosis) of 2 to 3 minutes duration plus severe constipation occurred in one patient that was administered 72 mg of ondansetron intravenously as a single dose. Hypotension (and faintness) occurred in another patient that took 48 mg of oral ondansetron. Following infusion of 32 mg over only a 4-minute period, a vasovagal episode with transient second-degree heart block was observed. Neuromuscular abnormalities, autonomic instability, somnolence, and a brief generalized tonic-clonic seizure (which resolved after a dose of benzodiazepine) were observed in a 12-month-old infant who ingested seven or eight 8-mg ondansetron tablets (approximately forty times the recommended 0.1-0.15 mg/kg dose for a pediatric patient). In all instances, however, the events resolved completely. The safety of ondansetron for use in human pregnancy has not been established. Ondansetron is not teratogenic in animals. However, as animal studies are not always predictive of human response, the use of ondansetron in pregnancy is not recommended. Ondansetron is excreted in the milk of lactating rats. It is not known if it is excreted in human milk, however, nursing is not recommended during treatment with ondansetron. Insufficient information is available to provide dosage recommendations for children 3 years of age or younger. •Brand Names (Drug A): Aplenzin, Auvelity, Budeprion, Contrave, Forfivo, Wellbutrin, Zyban •Brand Names (Drug B): Zofran, Zuplenz •Synonyms (Drug A): No synonyms listed •Synonyms (Drug B): No synonyms listed •Summary (Drug A): Bupropion is a norepinephrine and dopamine reuptake inhibitor used in the treatment of major depressive disorder (MDD), seasonal affective disorder (SAD), and as an aid to smoking cessation. •Summary (Drug B): Ondansetron is a serotonin 5-HT3 receptor antagonist used to prevent nausea and vomiting in cancer chemotherapy and postoperatively.

The subject drug is a strong CYP2D6 inhibitor and the affected drug is metabolized by CYP2D6. Concomitant administration may decrease the metabolism of the affected drug, which could increase serum concentrations as well as the risk and severity of adverse effects. The severity of the interaction is major.

Question: Does Bupropion and Ondansetron interact? Information: •Drug A: Bupropion •Drug B: Ondansetron •Severity: MAJOR •Description: The metabolism of Ondansetron can be decreased when combined with Bupropion. •Extended Description: The subject drug is a strong CYP2D6 inhibitor and the affected drug is metabolized by CYP2D6. Concomitant administration may decrease the metabolism of the affected drug, which could increase serum concentrations as well as the risk and severity of adverse effects. •Indication (Drug A): Bupropion is indicated for the treatment of major depressive disorder (MDD), seasonal affective disorder (SAD), and as an aid to smoking cessation. When used in combination with naltrexone as the marketed product ContraveⓇ, bupropion is indicated as an adjunct to a reduced-calorie diet and increased physical activity for chronic weight management in adults with an initial body mass index (BMI) of: 30 kg/m^2 or greater (obese) or 27 kg/m^2 or greater (overweight) in the presence of at least one weight-related comorbid condition (e.g., hypertension, type 2 diabetes mellitus, or dyslipidemia). Bupropion is also used off-label as a first-line treatment in patients with ADHD and comorbid bipolar disorder when used as an adjunct to mood stabilizers. •Indication (Drug B): In the adult patient population: i) orally administered ondansetron tablets and orally disintegrating tablets (ODT) are indicated for: - the prevention of nausea and vomiting associated with emetogenic cancer chemotherapy, including high dose (ie. greater than or equal to 50 mg/m2) cisplatin therapy, and radiotherapy, and - the prevention and treatment of postoperative nausea and vomiting ii) intravenously administered ondansetron injection formulations are indicated for: - the prevention of nausea and vomiting associated with emetogenic cancer chemotherapy, including high dose (ie. greater than or equal to 50 mg/m2) cisplatin therapy, and - the prevention and treatment of postoperative nausea and vomiting In the pediatric (4-18 years of age) patient population: i) ondansetron was effective and well tolerated when given to children 4-12 years of age for the treatment of post-chemotherapy induced nausea and vomiting, ii) ondansetron tablets, ondansetron ODT, ondansetron injection are not indicated for the treatment of children 3 years of age or younger, iii) ondansetron tablets, ondansetron ODT, ondansetron injection are not indicated for use in any age group of the pediatric population for the treatment of post-radiotherapy induced nausea and vomiting, and iV) ondansetron tablets, ondansetron ODT, ondansetron injection are not indicated for use in any age group of the pediatric population for the treatment of postoperative nausea and vomiting In the geriatric (>65 years of age) patient population: i) efficacy and tolerance of ondansetron were similar to that observed in younger adults for the treatment of post-chemotherapy and radiotherapy-induced nausea and vomiting, and ii) clinical experience in the use of ondansetron in the prevention and treatment of postoperative nausea and vomiting is limited and is not indicated for use in the geriatric patient population •Pharmacodynamics (Drug A): Bupropion is chemically unrelated to tricyclic, tetracyclic, selective serotonin re-uptake inhibitors, or other known antidepressant agents. Compared to classical tricyclic antidepressants, Bupropion is a relatively weak inhibitor of the neuronal uptake of norepinephrine and dopamine. In addition, Bupropion does not inhibit monoamine oxidase. Bupropion has been found to be essentially inactive at the serotonin transporter (SERT)(IC50 >10 000 nM), however both bupropion and its primary metabolite hydroxybupropion have been found to block the function of cation-selective serotonin type 3A receptors (5-HT3ARs). Bupropion produces dose-related central nervous system (CNS) stimulant effects in animals, as evidenced by increased locomotor activity, increased rates of responding in various schedule-controlled operant behaviour tasks, and, at high doses, induction of mild stereotyped behaviour. Due to these stimulant effects and selective activity at dopamine and norepinephrine receptors, bupropion has been identified as having an abuse potential. Bupropion has a similar structure to the controlled substance Cathinone, and has been identified as having mild amphetamine-like activity, particularly when inhaled or injected. Bupropion is also known to lower the seizure threshold, making any pre-existing seizure conditions a contraindication to its use. This risk is exacerbated when bupropion is combined with other drugs or substances that lower the seizure threshold, such as cocaine, or in clinical situations that would increase the risk of a seizure such as abrupt alcohol or benzodiazepine withdrawal. As norepinephrine has been shown to have anticonvulsant properties, bupropion's inhibitory effects on NET are thought to contribute to its pro-convulsant activity. Bupropion has been shown to increase blood pressure and pose a risk for exacerbation of unmanaged or pre-existing hypertension, however, clinical trials of bupropion in smokers with CVD have not identified an increased incidence of CV events including stroke or heart attack. In clinical trials, the mean increase in systolic blood pressure associated with the use of bupropion was found to be 1.3 mmHg. •Pharmacodynamics (Drug B): Ondansetron is a highly specific and selective serotonin 5-HT 3 receptor antagonist, not shown to have activity at other known serotonin receptors and with low affinity for dopamine receptors,. The serotonin 5-HT 3 receptors are located on the nerve terminals of the vagus in the periphery, and centrally in the chemoreceptor trigger zone of the area postrema,. The temporal relationship between the emetogenic action of emetogenic drugs and the release of serotonin, as well as the efficacy of antiemetic agents, suggest that chemotherapeutic agents release serotonin from the enterochromaffin cells of the small intestine by causing degenerative changes in the GI tract,. The serotonin then stimulates the vagal and splanchnic nerve receptors that project to the medullary vomiting center, as well as the 5-HT 3 receptors in the area postrema, thus initiating the vomiting reflex, causing nausea and vomiting,. Moreover, the effect of ondansetron on the QTc interval was evaluated in a double-blind, randomized, placebo and positive (moxifloxacin) controlled, crossover study in 58 healthy adult men and women. Ondansetron was tested at single doses of 8 mg and 32 mg infused intravenously over 15 minutes. At the highest tested dose of 32 mg, prolongation of the Fridericia-corrected QTc interval (QT/RR0.33=QTcF) was observed from 15 min to 4 h after the start of the 15 min infusion, with a maximum mean (upper limit of 90% CI) difference in QTcF from placebo after baseline-correction of 19.6 (21.5) msec at 20 min. At the lower tested dose of 8 mg, QTc prolongation was observed from 15 min to 1 h after the start of the 15-minute infusion, with a maximum mean (upper limit of 90% CI) difference in QTcF from placebo after baseline-correction of 5.8 (7.8) msec at 15 min. The magnitude of QTc prolongation with ondansetron is expected to be greater if the infusion rate is faster than 15 minutes. The 32 mg intravenous dose of ondansetron must not be administered. No treatment-related effects on the QRS duration or the PR interval were observed at either the 8 or 32 mg dose. An ECG assessment study has not been performed for orally administered ondansetron. On the basis of pharmacokinetic-pharmacodynamic modelling, an 8 mg oral dose of ondansetron is predicted to cause a mean QTcF increase of 0.7 ms (90% CI -2.1, 3.3) at steady-state, assuming a mean maximal plasma concentration of 24.7 ng/mL (95% CI 21.1, 29.0). The magnitude of QTc prolongation at the recommended 5 mg/m2 dose in pediatrics has not been studied, but pharmacokinetic-pharmacodynamic modeling predicts a mean increase of 6.6 ms (90% CI 2.8, 10.7) at maximal plasma concentrations. In healthy subjects, single intravenous doses of 0.15 mg/kg of ondansetron had no effect on esophageal motility, gastric motility, lower esophageal sphincter pressure, or small intestinal transit time. Multiday administration of ondansetron has been shown to slow colonic transit in healthy subjects. Ondansetron has no effect on plasma prolactin concentrations. •Mechanism of action (Drug A): Bupropion is a norepinephrine/dopamine-reuptake inhibitor (NDRI) that exerts its pharmacological effects by weakly inhibiting the enzymes involved in the uptake of the neurotransmitters norepinephrine and dopamine from the synaptic cleft, therefore prolonging their duration of action within the neuronal synapse and the downstream effects of these neurotransmitters. More specifically, bupropion binds to the norepinephrine transporter (NET) and the dopamine transporter (DAT). Bupropion was originally classified as an "atypical" antidepressant because it does not exert the same effects as the classical antidepressants such as Monoamine Oxidase Inhibitors (MAOIs), Tricyclic Antidepressants (TCAs), or Selective Serotonin Reuptake Inhibitors (SSRIs). While it has comparable effectiveness to typical first-line options for the treatment of depression such as SSRIs, bupropion is a unique option for the treatment of MDD as it lacks any clinically relevant serotonergic effects, typical of other mood medications, or any effects on histamine or adrenaline receptors. Lack of activity at these receptors results in a more tolerable side effect profile; bupropion is less likely to cause sexual side effects, sedation, or weight gain as compared to SSRIs or TCAs, for example. When used as an aid to smoking cessation, bupropion is thought to confer its anti-craving and anti-withdrawal effects by inhibiting dopamine reuptake, which is thought to be involved in the reward pathways associated with nicotine, and through the antagonism of the nicotinic acetylcholinergic receptor (AChR), thereby blunting the effects of nicotine. Furthermore, the stimulatory effects produced by bupropion in the central nervous system are similar to nicotine's effects, making low doses of bupropion a suitable option as a nicotine substitute. When used in combination with naltrexone in the marketed product ContraveⓇ for chronic weight management, the two components are thought to have effects on areas of the brain involved in the regulation of food intake. This includes the hypothalamus, which is involved in appetite regulation, and the mesolimbic dopamine circuit, which is involved in reward pathways. Studies have shown that the combined activity of bupropion and naltrexone increase the firing rate of hypothalamic pro-opiomelanocortin (POMC) neurons and blockade of opioid receptor-mediated POMC auto-inhibition, which are associated with a reduction in food intake and increased energy expenditure. This combination was also found to reduce food intake when injected directly into the ventral tegmental area of the mesolimbic circuit in mice, which is an area associated with the regulation of reward pathways. •Mechanism of action (Drug B): Ondansetron is a selective antagonist of the serotonin receptor subtype, 5-HT3. Cytotoxic chemotherapy and radiotherapy are associated with the release of serotonin (5-HT) from enterochromaffin cells of the small intestine, presumably initiating a vomiting reflex through stimulation of 5-HT3 receptors located on vagal afferents. Ondansetron may block the initiation of this reflex. Activation of vagal afferents may also cause a central release of serotonin from the chemoreceptor trigger zone of the area postrema, located on the floor of the fourth ventricle. Thus, the antiemetic effect of ondansetron is probably due to the selective antagonism of 5-HT3 receptors on neurons located in either the peripheral or central nervous systems, or both. Although the mechanisms of action of ondansetron in treating postoperative nausea and vomiting and cytotoxic induced nausea and vomiting may share similar pathways, the role of ondansetron in opiate-induced emesis has not yet been formally established. •Absorption (Drug A): Bupropion is currently available in 3 distinct, but bioequivalent formulations: immediate release (IR), sustained-release (SR), and extended-release (XL). Immediate Release Formulation In humans, following oral administration of bupropion hydrochloride tablets, peak plasma bupropion concentrations are usually achieved within 2 hours. IR formulations provide a short duration of action and are therefore generally dosed three times per day. Sustained Release Formulation In humans, following oral administration of bupropion hydrochloride sustained-release tablets (SR), peak plasma concentration (Cmax) of bupropion is usually achieved within 3 hours. SR formulations provide a 12-hour extended release of medication and are therefore generally dosed twice per day. Extended Release Formulation Following single oral administration of bupropion hydrochloride extended-release tablets (XL) to healthy volunteers, the median time to peak plasma concentrations for bupropion was approximately 5 hours. The presence of food did not affect the peak concentration or area under the curve of bupropion. XL formulations provide a 24-hour extended release of medication and are therefore generally dosed once per day/ In a trial comparing chronic dosing with bupropion hydrochloride extended-release tablets (SR) 150 mg twice daily to bupropion immediate-release formulation 100 mg 3 times daily, the steady state Cmax for bupropion after bupropion hydrochloride sustained-release tablets (SR) administration was approximately 85% of those achieved after bupropion immediate-release formulation administration. Exposure (AUC) to bupropion was equivalent for both formulations. Bioequivalence was also demonstrated for all three major active metabolites (i.e., hydroxybupropion, threohydrobupropion and erythrohydrobupropion) for both Cmax and AUC. Thus, at steady state, bupropion hydrochloride sustained-release tablets (SR) given twice daily, and the immediate-release formulation of bupropion given 3 times daily, are essentially bioequivalent for both bupropion and the 3 quantitatively important metabolites. Furthermore, in a study comparing 14-day dosing with bupropion hydrochloride extended-release tablets (XL), 300 mg once-daily to the immediate-release formulation of bupropion at 100 mg 3 times daily, equivalence was demonstrated for peak plasma concentration and area under the curve for bupropion and the three metabolites (hydroxybupropion, threohydrobupropion, and erythrohydrobupropion). Additionally, in a study comparing 14-day dosing with bupropion hydrochloride extended-release tablets (XL) 300 mg once daily to the sustained-release formulation of bupropion at 150 mg 2 times daily, equivalence was demonstrated for peak plasma concentration and area under the curve for bupropion and the three metabolites. Bupropion hydrochloride extended-release tablets (SR) can be taken with or without food. Bupropion Cmax and AUC were increased by 11% to 35% and 16% to 19%, respectively, when bupropion hydrochloride extended-release tablets (SR) was administered with food to healthy volunteers in three trials. The food effect is not considered clinically significant. Following a single-dose administration of bupropion hydrochloride extended-release tablets (SR) in humans, Cmax of bupropion's metabolite hydroxybupropion occurs approximately 6 hours post-dose and is approximately 10 times the peak level of the parent drug at steady state. The elimination half-life of hydroxybupropion is approximately 20 (±5) hours and its AUC at steady state is about 17 times that of bupropion. The times to peak concentrations for the erythrohydrobupropion and threohydrobupropion metabolites are similar to that of the hydroxybupropion metabolite. However, their elimination half-lives are longer, 33(±10) and 37 (±13) hours, respectively, and steady-state AUCs are 1.5 and 7 times that of bupropion, respectively. •Absorption (Drug B): Ondansetron is absorbed from the gastrointestinal tract and undergoes some limited first-pass metabolism. Mean bioavailability in healthy subjects, following administration of a single 8-mg tablet, was recorded as being approximately 56% to 60%. Bioavailability is also slightly enhanced by the presence of food. Ondansetron systemic exposure does not increase proportionately to dose. The AUC from a 16-mg tablet was 24% greater than predicted from an 8-mg tablet dose. This may reflect some reduction of first-pass metabolism at higher oral doses. •Volume of distribution (Drug A): No volume of distribution available •Volume of distribution (Drug B): The volume of distribution of ondansetron has been recorded as being approximately 160L. •Protein binding (Drug A): In vitro tests show that bupropion is 84% bound to human plasma proteins at concentrations up to 200 mcg per mL. The extent of protein binding of the hydroxybupropion metabolite is similar to that for bupropion, whereas the extent of protein binding of the threohydrobupropion metabolite is about half that seen with bupropion. •Protein binding (Drug B): The plasma protein binding associated with ondansetron was documented as approximately 73%. •Metabolism (Drug A): Bupropion is extensively metabolized in humans. Three metabolites are active: hydroxybupropion, which is formed via hydroxylation of the tert-butyl group of bupropion, and the amino-alcohol isomers, threohydrobupropion and erythrohydrobupropion, which are formed via reduction of the carbonyl group. In vitro findings suggest that CYP2B6 is the principal isoenzyme involved in the formation of hydroxybupropion, while cytochrome P450 enzymes are not involved in the formation of threohydrobupropion. Hydroxybupropion has been shown to have the same affinity as bupropion for the norepinephrine transporter (NET) but approximately 50% of its antidepressant activity despite reaching concentrations of ~10-fold higher than that of the parent drug. Oxidation of the bupropion side chain results in the formation of a glycine conjugate of meta-chlorobenzoic acid, which is then excreted as the major urinary metabolite. The potency and toxicity of the metabolites relative to bupropion have not been fully characterized. However, it has been demonstrated in an antidepressant screening test in mice that hydroxybupropion is one-half as potent as bupropion, while threohydrobupropion and erythrohydrobupropion are 5-fold less potent than bupropion. This may be of clinical importance because the plasma concentrations of the metabolites are as high as or higher than those of bupropion. Bupropion and its metabolites exhibit linear kinetics following chronic administration of 300 to 450 mg per day. •Metabolism (Drug B): In vitro metabolism studies have shown that ondansetron is a substrate for human hepatic cytochrome P450 enzymes, including CYP1A2, CYP2D6 and CYP3A4. In terms of overall ondansetron turnover, CYP3A4 played the predominant role. Because of the multiplicity of metabolic enzymes capable of metabolizing ondansetron, it is likely that inhibition or loss of one enzyme (e.g. CYP2D6 enzyme deficiency) will be compensated by others and may result in little change in overall rates of ondansetron clearance. Following oral or IV administration, ondansetron is extensively metabolised and excreted in the urine and faeces. In humans, less than 10% of the dose is excreted unchanged in the urine. The major urinary metabolites are glucuronide conjugates (45%), sulphate conjugates (20%) and hydroxylation products (10%). The primary metabolic pathway is subsequently hydroxylation on the indole ring followed by subsequent glucuronide or sulfate conjugation. Although some nonconjugated metabolites have pharmacologic activity, these are not found in plasma at concentrations likely to significantly contribute to the biological activity of ondansetron. •Route of elimination (Drug A): Bupropion is extensively metabolized in humans. Oxidation of the bupropion side chain results in the formation of a glycine conjugate of metachlorobenzoic acid, which is then excreted as the major urinary metabolite. Following oral administration of 200 mg of 14C-bupropion in humans, 87% and 10% of the radioactive dose were recovered in the urine and feces, respectively. However, the fraction of the oral dose of bupropion excreted unchanged was only 0.5%, a finding consistent with the extensive metabolism of bupropion. •Route of elimination (Drug B): Following oral or IV administration, ondansetron is extensively metabolised and excreted in the urine and faeces. •Half-life (Drug A): 24 hours •Half-life (Drug B): The half-life of ondansetron after either an 8 mg oral dose or intravenous dose was approximately 3-4 hours and could be extended to 6-8 hours in the elderly. •Clearance (Drug A): No clearance available •Clearance (Drug B): The clearance values determined for ondansetron in various patient age groups were recorded as approximately 0.38 L/h/kg in normal adult volunteers aged 19-40 yrs, 0.32 L/h/kg in normal adult volunteers aged 61-74 yrs, 0.26 L/h/kg in normal adult volunteers aged >=75 yrs. •Toxicity (Drug A): Symptoms of overdose include seizures, hallucinations, loss of consciousness, tachycardia, and cardiac arrest. •Toxicity (Drug B): At present, there is little information concerning overdosage with ondansetron. Nevertheless, there have been certain cases of somewhat idiosyncratic adverse effects associated with particular dosages of ondansetron used. “Sudden blindness” (amaurosis) of 2 to 3 minutes duration plus severe constipation occurred in one patient that was administered 72 mg of ondansetron intravenously as a single dose. Hypotension (and faintness) occurred in another patient that took 48 mg of oral ondansetron. Following infusion of 32 mg over only a 4-minute period, a vasovagal episode with transient second-degree heart block was observed. Neuromuscular abnormalities, autonomic instability, somnolence, and a brief generalized tonic-clonic seizure (which resolved after a dose of benzodiazepine) were observed in a 12-month-old infant who ingested seven or eight 8-mg ondansetron tablets (approximately forty times the recommended 0.1-0.15 mg/kg dose for a pediatric patient). In all instances, however, the events resolved completely. The safety of ondansetron for use in human pregnancy has not been established. Ondansetron is not teratogenic in animals. However, as animal studies are not always predictive of human response, the use of ondansetron in pregnancy is not recommended. Ondansetron is excreted in the milk of lactating rats. It is not known if it is excreted in human milk, however, nursing is not recommended during treatment with ondansetron. Insufficient information is available to provide dosage recommendations for children 3 years of age or younger. •Brand Names (Drug A): Aplenzin, Auvelity, Budeprion, Contrave, Forfivo, Wellbutrin, Zyban •Brand Names (Drug B): Zofran, Zuplenz •Synonyms (Drug A): No synonyms listed •Synonyms (Drug B): No synonyms listed •Summary (Drug A): Bupropion is a norepinephrine and dopamine reuptake inhibitor used in the treatment of major depressive disorder (MDD), seasonal affective disorder (SAD), and as an aid to smoking cessation. •Summary (Drug B): Ondansetron is a serotonin 5-HT3 receptor antagonist used to prevent nausea and vomiting in cancer chemotherapy and postoperatively. Output: The subject drug is a strong CYP2D6 inhibitor and the affected drug is metabolized by CYP2D6. Concomitant administration may decrease the metabolism of the affected drug, which could increase serum concentrations as well as the risk and severity of adverse effects. The severity of the interaction is major.

Does Bupropion and Opicapone interact?

•Drug A: Bupropion •Drug B: Opicapone •Severity: MODERATE •Description: The risk or severity of adverse effects can be increased when Bupropion is combined with Opicapone. •Extended Description: Despite the fact that these drugs are sometimes used in combination to treat depression in Parkinson's disease3, the administration of bupropion with anti-Parkinson drugs may lead to central nervous system toxicity. Bupropion is considered a norepinephrine-dopamine reuptake inhibitor, is found to occupy the DAT dopamine transporter, and acts as a dopamine agonist. Additive effects of these dopaminergic drugs may produce excess dopaminergic activity. Agitation, restlessness, tremor, ataxia, gait disturbance, and dizziness are some examples of effects that may occur from concurrent administration. •Indication (Drug A): Bupropion is indicated for the treatment of major depressive disorder (MDD), seasonal affective disorder (SAD), and as an aid to smoking cessation. When used in combination with naltrexone as the marketed product ContraveⓇ, bupropion is indicated as an adjunct to a reduced-calorie diet and increased physical activity for chronic weight management in adults with an initial body mass index (BMI) of: 30 kg/m^2 or greater (obese) or 27 kg/m^2 or greater (overweight) in the presence of at least one weight-related comorbid condition (e.g., hypertension, type 2 diabetes mellitus, or dyslipidemia). Bupropion is also used off-label as a first-line treatment in patients with ADHD and comorbid bipolar disorder when used as an adjunct to mood stabilizers. •Indication (Drug B): Opicapone is indicated as adjunctive therapy in adults with Parkinson’s disease and end-of-dose motor fluctuations or “off” episodes whose symptoms cannot be stabilized on the combination therapy of levodopa and DOPA decarboxylase inhibitor (e.g., carbidopa). •Pharmacodynamics (Drug A): Bupropion is chemically unrelated to tricyclic, tetracyclic, selective serotonin re-uptake inhibitors, or other known antidepressant agents. Compared to classical tricyclic antidepressants, Bupropion is a relatively weak inhibitor of the neuronal uptake of norepinephrine and dopamine. In addition, Bupropion does not inhibit monoamine oxidase. Bupropion has been found to be essentially inactive at the serotonin transporter (SERT)(IC50 >10 000 nM), however both bupropion and its primary metabolite hydroxybupropion have been found to block the function of cation-selective serotonin type 3A receptors (5-HT3ARs). Bupropion produces dose-related central nervous system (CNS) stimulant effects in animals, as evidenced by increased locomotor activity, increased rates of responding in various schedule-controlled operant behaviour tasks, and, at high doses, induction of mild stereotyped behaviour. Due to these stimulant effects and selective activity at dopamine and norepinephrine receptors, bupropion has been identified as having an abuse potential. Bupropion has a similar structure to the controlled substance Cathinone, and has been identified as having mild amphetamine-like activity, particularly when inhaled or injected. Bupropion is also known to lower the seizure threshold, making any pre-existing seizure conditions a contraindication to its use. This risk is exacerbated when bupropion is combined with other drugs or substances that lower the seizure threshold, such as cocaine, or in clinical situations that would increase the risk of a seizure such as abrupt alcohol or benzodiazepine withdrawal. As norepinephrine has been shown to have anticonvulsant properties, bupropion's inhibitory effects on NET are thought to contribute to its pro-convulsant activity. Bupropion has been shown to increase blood pressure and pose a risk for exacerbation of unmanaged or pre-existing hypertension, however, clinical trials of bupropion in smokers with CVD have not identified an increased incidence of CV events including stroke or heart attack. In clinical trials, the mean increase in systolic blood pressure associated with the use of bupropion was found to be 1.3 mmHg. •Pharmacodynamics (Drug B): Opicapone is a COMT inhibitor that serves to improve the availability and duration of action of levodopa (L-Dopa), a standard pharmacological treatment for Parkinson's Disease. Opicapone works by blocking the peripheral degradation of L-Dopa mediated by COMT. Opicapone has a long duration of action: following administration of a 50 mg dose, COMT inhibition lasted for more than 24 hours. In clinical trials, opicapone as adjunct therapy to L-Dopa plus a dopa decarboxylase inhibitor significantly improved motor fluctuations than placebo, and the effects were comparable to entacapone. •Mechanism of action (Drug A): Bupropion is a norepinephrine/dopamine-reuptake inhibitor (NDRI) that exerts its pharmacological effects by weakly inhibiting the enzymes involved in the uptake of the neurotransmitters norepinephrine and dopamine from the synaptic cleft, therefore prolonging their duration of action within the neuronal synapse and the downstream effects of these neurotransmitters. More specifically, bupropion binds to the norepinephrine transporter (NET) and the dopamine transporter (DAT). Bupropion was originally classified as an "atypical" antidepressant because it does not exert the same effects as the classical antidepressants such as Monoamine Oxidase Inhibitors (MAOIs), Tricyclic Antidepressants (TCAs), or Selective Serotonin Reuptake Inhibitors (SSRIs). While it has comparable effectiveness to typical first-line options for the treatment of depression such as SSRIs, bupropion is a unique option for the treatment of MDD as it lacks any clinically relevant serotonergic effects, typical of other mood medications, or any effects on histamine or adrenaline receptors. Lack of activity at these receptors results in a more tolerable side effect profile; bupropion is less likely to cause sexual side effects, sedation, or weight gain as compared to SSRIs or TCAs, for example. When used as an aid to smoking cessation, bupropion is thought to confer its anti-craving and anti-withdrawal effects by inhibiting dopamine reuptake, which is thought to be involved in the reward pathways associated with nicotine, and through the antagonism of the nicotinic acetylcholinergic receptor (AChR), thereby blunting the effects of nicotine. Furthermore, the stimulatory effects produced by bupropion in the central nervous system are similar to nicotine's effects, making low doses of bupropion a suitable option as a nicotine substitute. When used in combination with naltrexone in the marketed product ContraveⓇ for chronic weight management, the two components are thought to have effects on areas of the brain involved in the regulation of food intake. This includes the hypothalamus, which is involved in appetite regulation, and the mesolimbic dopamine circuit, which is involved in reward pathways. Studies have shown that the combined activity of bupropion and naltrexone increase the firing rate of hypothalamic pro-opiomelanocortin (POMC) neurons and blockade of opioid receptor-mediated POMC auto-inhibition, which are associated with a reduction in food intake and increased energy expenditure. This combination was also found to reduce food intake when injected directly into the ventral tegmental area of the mesolimbic circuit in mice, which is an area associated with the regulation of reward pathways. •Mechanism of action (Drug B): Levodopa (L-Dopa) is the gold standard for managing motor and some non-motor symptoms associated with Parkinson's Disease; however, only a small fraction of administered L-Dopa actually crosses the blood-brain barrier to exert its therapeutic action and patients face the risk of developing end-of-dose motor fluctuations, which reflects the rapid peripheral metabolism of L-dopa by aromatic L-amino acid decarboxylase and catechol-O-methyltransferase (COMT). Opicapone is a peripheral, selective, and reversible catechol-O-methyltransferase (COMT) inhibitor. It displays a high binding affinity that is in sub-picomolar ranges, resulting in a slow complex dissociation rate constant and long duration of action in vivo. When opicapone is added to the treatment regimen that contains L-Dopa and DOPA decarboxylase inhibitor, opicapone helps to increase the plasma levels and enhance the therapeutic efficacy of L-Dopa. •Absorption (Drug A): Bupropion is currently available in 3 distinct, but bioequivalent formulations: immediate release (IR), sustained-release (SR), and extended-release (XL). Immediate Release Formulation In humans, following oral administration of bupropion hydrochloride tablets, peak plasma bupropion concentrations are usually achieved within 2 hours. IR formulations provide a short duration of action and are therefore generally dosed three times per day. Sustained Release Formulation In humans, following oral administration of bupropion hydrochloride sustained-release tablets (SR), peak plasma concentration (Cmax) of bupropion is usually achieved within 3 hours. SR formulations provide a 12-hour extended release of medication and are therefore generally dosed twice per day. Extended Release Formulation Following single oral administration of bupropion hydrochloride extended-release tablets (XL) to healthy volunteers, the median time to peak plasma concentrations for bupropion was approximately 5 hours. The presence of food did not affect the peak concentration or area under the curve of bupropion. XL formulations provide a 24-hour extended release of medication and are therefore generally dosed once per day/ In a trial comparing chronic dosing with bupropion hydrochloride extended-release tablets (SR) 150 mg twice daily to bupropion immediate-release formulation 100 mg 3 times daily, the steady state Cmax for bupropion after bupropion hydrochloride sustained-release tablets (SR) administration was approximately 85% of those achieved after bupropion immediate-release formulation administration. Exposure (AUC) to bupropion was equivalent for both formulations. Bioequivalence was also demonstrated for all three major active metabolites (i.e., hydroxybupropion, threohydrobupropion and erythrohydrobupropion) for both Cmax and AUC. Thus, at steady state, bupropion hydrochloride sustained-release tablets (SR) given twice daily, and the immediate-release formulation of bupropion given 3 times daily, are essentially bioequivalent for both bupropion and the 3 quantitatively important metabolites. Furthermore, in a study comparing 14-day dosing with bupropion hydrochloride extended-release tablets (XL), 300 mg once-daily to the immediate-release formulation of bupropion at 100 mg 3 times daily, equivalence was demonstrated for peak plasma concentration and area under the curve for bupropion and the three metabolites (hydroxybupropion, threohydrobupropion, and erythrohydrobupropion). Additionally, in a study comparing 14-day dosing with bupropion hydrochloride extended-release tablets (XL) 300 mg once daily to the sustained-release formulation of bupropion at 150 mg 2 times daily, equivalence was demonstrated for peak plasma concentration and area under the curve for bupropion and the three metabolites. Bupropion hydrochloride extended-release tablets (SR) can be taken with or without food. Bupropion Cmax and AUC were increased by 11% to 35% and 16% to 19%, respectively, when bupropion hydrochloride extended-release tablets (SR) was administered with food to healthy volunteers in three trials. The food effect is not considered clinically significant. Following a single-dose administration of bupropion hydrochloride extended-release tablets (SR) in humans, Cmax of bupropion's metabolite hydroxybupropion occurs approximately 6 hours post-dose and is approximately 10 times the peak level of the parent drug at steady state. The elimination half-life of hydroxybupropion is approximately 20 (±5) hours and its AUC at steady state is about 17 times that of bupropion. The times to peak concentrations for the erythrohydrobupropion and threohydrobupropion metabolites are similar to that of the hydroxybupropion metabolite. However, their elimination half-lives are longer, 33(±10) and 37 (±13) hours, respectively, and steady-state AUCs are 1.5 and 7 times that of bupropion, respectively. •Absorption (Drug B): Orally administered opicapone demonstrates a linear, dose-dependent absorption profile. Opicapone is rapidly absorbed, with an oral bioavailability of about 20%. Following administration of a single 50 mg dose of opicapone, the median T max was two hours, ranging from one to four hours. A moderate fat or moderate calorie meal was shown to decrease the C max by 62%, the mean overall plasma exposure (AUC) by 31%, and the Tmax by 4 hours. •Volume of distribution (Drug A): No volume of distribution available •Volume of distribution (Drug B): Following oral administration, the apparent V d of opicapone at a dose of 50 mg was 29 L with an inter-subject variability of 36%. One study showed small systemic accumulation after multiple-dosing. •Protein binding (Drug A): In vitro tests show that bupropion is 84% bound to human plasma proteins at concentrations up to 200 mcg per mL. The extent of protein binding of the hydroxybupropion metabolite is similar to that for bupropion, whereas the extent of protein binding of the threohydrobupropion metabolite is about half that seen with bupropion. •Protein binding (Drug B): Opicapone is >99% bound to plasma proteins, which is independent of the drug concentration. •Metabolism (Drug A): Bupropion is extensively metabolized in humans. Three metabolites are active: hydroxybupropion, which is formed via hydroxylation of the tert-butyl group of bupropion, and the amino-alcohol isomers, threohydrobupropion and erythrohydrobupropion, which are formed via reduction of the carbonyl group. In vitro findings suggest that CYP2B6 is the principal isoenzyme involved in the formation of hydroxybupropion, while cytochrome P450 enzymes are not involved in the formation of threohydrobupropion. Hydroxybupropion has been shown to have the same affinity as bupropion for the norepinephrine transporter (NET) but approximately 50% of its antidepressant activity despite reaching concentrations of ~10-fold higher than that of the parent drug. Oxidation of the bupropion side chain results in the formation of a glycine conjugate of meta-chlorobenzoic acid, which is then excreted as the major urinary metabolite. The potency and toxicity of the metabolites relative to bupropion have not been fully characterized. However, it has been demonstrated in an antidepressant screening test in mice that hydroxybupropion is one-half as potent as bupropion, while threohydrobupropion and erythrohydrobupropion are 5-fold less potent than bupropion. This may be of clinical importance because the plasma concentrations of the metabolites are as high as or higher than those of bupropion. Bupropion and its metabolites exhibit linear kinetics following chronic administration of 300 to 450 mg per day. •Metabolism (Drug B): According to clinical and in vitro studies, sulphation is the primary metabolic pathway of opicapone, forming the inactive metabolite. Opicapone can also undergo glucuronidation, COMT-mediated methylation, reduction, and glutathione conjugation. As two major circulating metabolites, BIA 9-1103 (3-O-sulphated opicapone) accounts for 67.1% of the total radioactivity and BIA 9-1104 (4-O-methylated opicapone) accounts for 20.5% of the total radioactivity. Other metabolites are generally unquantifiable in plasma samples. Opicapone can undergo N-oxide reduction to form BIA 9-1079, which was shown to be an active metabolite in non-clinical studies; however, it is generally undetectable in humans. Other inactive metabolites include BIA 9-1100, BIA 9-1101, and BIA 9-1106. •Route of elimination (Drug A): Bupropion is extensively metabolized in humans. Oxidation of the bupropion side chain results in the formation of a glycine conjugate of metachlorobenzoic acid, which is then excreted as the major urinary metabolite. Following oral administration of 200 mg of 14C-bupropion in humans, 87% and 10% of the radioactive dose were recovered in the urine and feces, respectively. However, the fraction of the oral dose of bupropion excreted unchanged was only 0.5%, a finding consistent with the extensive metabolism of bupropion. •Route of elimination (Drug B): Following administration of a single 100 mg dose of radiolabeled opicapone in healthy subjects, about 70% of the total dose was recovered in feces, where 22% of the recovered dose was excreted as an unchanged parent drug. About 20% of the total dose was recovered in exhaled air and about 5% was recovered in the urine, where less than 1% of the recovered dose was in an unchanged form. The primary detectable metabolite in the urine was the glucuronide metabolite. •Half-life (Drug A): 24 hours •Half-life (Drug B): The mean elimination half-life of opicapone is one to two hours. Despite the short half-life, the observed half-life of opicapone-induced COMT inhibition in human red blood cells was 61.6 hours with a standard deviation of 37.6 hours. •Clearance (Drug A): No clearance available •Clearance (Drug B): Following oral administration of 50 mg opicapone, the apparent total body clearance was 22 L/h, with an inter-subject variability of 45%. •Toxicity (Drug A): Symptoms of overdose include seizures, hallucinations, loss of consciousness, tachycardia, and cardiac arrest. •Toxicity (Drug B): There is no reported LD 50 data of opicapone. As there is no known antidote for opicapone overdose, overdosage should be managed with symptomatic and supportive treatment. Removal of the drug through gastric lavage and/or inactivation by administering activated charcoal should be considered. •Brand Names (Drug A): Aplenzin, Auvelity, Budeprion, Contrave, Forfivo, Wellbutrin, Zyban •Brand Names (Drug B): Ongentys •Synonyms (Drug A): No synonyms listed •Synonyms (Drug B): No synonyms listed •Summary (Drug A): Bupropion is a norepinephrine and dopamine reuptake inhibitor used in the treatment of major depressive disorder (MDD), seasonal affective disorder (SAD), and as an aid to smoking cessation. •Summary (Drug B): Opicapone is a catechol-O-methyltransferase inhibitor used as an adjunct treatment for Parkinson's Disease in adults currently receiving levodopa and a dopa decarboxylase inhibitor.

Despite the fact that these drugs are sometimes used in combination to treat depression in Parkinson's disease3, the administration of bupropion with anti-Parkinson drugs may lead to central nervous system toxicity. Bupropion is considered a norepinephrine-dopamine reuptake inhibitor, is found to occupy the DAT dopamine transporter, and acts as a dopamine agonist. Additive effects of these dopaminergic drugs may produce excess dopaminergic activity. Agitation, restlessness, tremor, ataxia, gait disturbance, and dizziness are some examples of effects that may occur from concurrent administration. The severity of the interaction is moderate.

Question: Does Bupropion and Opicapone interact? Information: •Drug A: Bupropion •Drug B: Opicapone •Severity: MODERATE •Description: The risk or severity of adverse effects can be increased when Bupropion is combined with Opicapone. •Extended Description: Despite the fact that these drugs are sometimes used in combination to treat depression in Parkinson's disease3, the administration of bupropion with anti-Parkinson drugs may lead to central nervous system toxicity. Bupropion is considered a norepinephrine-dopamine reuptake inhibitor, is found to occupy the DAT dopamine transporter, and acts as a dopamine agonist. Additive effects of these dopaminergic drugs may produce excess dopaminergic activity. Agitation, restlessness, tremor, ataxia, gait disturbance, and dizziness are some examples of effects that may occur from concurrent administration. •Indication (Drug A): Bupropion is indicated for the treatment of major depressive disorder (MDD), seasonal affective disorder (SAD), and as an aid to smoking cessation. When used in combination with naltrexone as the marketed product ContraveⓇ, bupropion is indicated as an adjunct to a reduced-calorie diet and increased physical activity for chronic weight management in adults with an initial body mass index (BMI) of: 30 kg/m^2 or greater (obese) or 27 kg/m^2 or greater (overweight) in the presence of at least one weight-related comorbid condition (e.g., hypertension, type 2 diabetes mellitus, or dyslipidemia). Bupropion is also used off-label as a first-line treatment in patients with ADHD and comorbid bipolar disorder when used as an adjunct to mood stabilizers. •Indication (Drug B): Opicapone is indicated as adjunctive therapy in adults with Parkinson’s disease and end-of-dose motor fluctuations or “off” episodes whose symptoms cannot be stabilized on the combination therapy of levodopa and DOPA decarboxylase inhibitor (e.g., carbidopa). •Pharmacodynamics (Drug A): Bupropion is chemically unrelated to tricyclic, tetracyclic, selective serotonin re-uptake inhibitors, or other known antidepressant agents. Compared to classical tricyclic antidepressants, Bupropion is a relatively weak inhibitor of the neuronal uptake of norepinephrine and dopamine. In addition, Bupropion does not inhibit monoamine oxidase. Bupropion has been found to be essentially inactive at the serotonin transporter (SERT)(IC50 >10 000 nM), however both bupropion and its primary metabolite hydroxybupropion have been found to block the function of cation-selective serotonin type 3A receptors (5-HT3ARs). Bupropion produces dose-related central nervous system (CNS) stimulant effects in animals, as evidenced by increased locomotor activity, increased rates of responding in various schedule-controlled operant behaviour tasks, and, at high doses, induction of mild stereotyped behaviour. Due to these stimulant effects and selective activity at dopamine and norepinephrine receptors, bupropion has been identified as having an abuse potential. Bupropion has a similar structure to the controlled substance Cathinone, and has been identified as having mild amphetamine-like activity, particularly when inhaled or injected. Bupropion is also known to lower the seizure threshold, making any pre-existing seizure conditions a contraindication to its use. This risk is exacerbated when bupropion is combined with other drugs or substances that lower the seizure threshold, such as cocaine, or in clinical situations that would increase the risk of a seizure such as abrupt alcohol or benzodiazepine withdrawal. As norepinephrine has been shown to have anticonvulsant properties, bupropion's inhibitory effects on NET are thought to contribute to its pro-convulsant activity. Bupropion has been shown to increase blood pressure and pose a risk for exacerbation of unmanaged or pre-existing hypertension, however, clinical trials of bupropion in smokers with CVD have not identified an increased incidence of CV events including stroke or heart attack. In clinical trials, the mean increase in systolic blood pressure associated with the use of bupropion was found to be 1.3 mmHg. •Pharmacodynamics (Drug B): Opicapone is a COMT inhibitor that serves to improve the availability and duration of action of levodopa (L-Dopa), a standard pharmacological treatment for Parkinson's Disease. Opicapone works by blocking the peripheral degradation of L-Dopa mediated by COMT. Opicapone has a long duration of action: following administration of a 50 mg dose, COMT inhibition lasted for more than 24 hours. In clinical trials, opicapone as adjunct therapy to L-Dopa plus a dopa decarboxylase inhibitor significantly improved motor fluctuations than placebo, and the effects were comparable to entacapone. •Mechanism of action (Drug A): Bupropion is a norepinephrine/dopamine-reuptake inhibitor (NDRI) that exerts its pharmacological effects by weakly inhibiting the enzymes involved in the uptake of the neurotransmitters norepinephrine and dopamine from the synaptic cleft, therefore prolonging their duration of action within the neuronal synapse and the downstream effects of these neurotransmitters. More specifically, bupropion binds to the norepinephrine transporter (NET) and the dopamine transporter (DAT). Bupropion was originally classified as an "atypical" antidepressant because it does not exert the same effects as the classical antidepressants such as Monoamine Oxidase Inhibitors (MAOIs), Tricyclic Antidepressants (TCAs), or Selective Serotonin Reuptake Inhibitors (SSRIs). While it has comparable effectiveness to typical first-line options for the treatment of depression such as SSRIs, bupropion is a unique option for the treatment of MDD as it lacks any clinically relevant serotonergic effects, typical of other mood medications, or any effects on histamine or adrenaline receptors. Lack of activity at these receptors results in a more tolerable side effect profile; bupropion is less likely to cause sexual side effects, sedation, or weight gain as compared to SSRIs or TCAs, for example. When used as an aid to smoking cessation, bupropion is thought to confer its anti-craving and anti-withdrawal effects by inhibiting dopamine reuptake, which is thought to be involved in the reward pathways associated with nicotine, and through the antagonism of the nicotinic acetylcholinergic receptor (AChR), thereby blunting the effects of nicotine. Furthermore, the stimulatory effects produced by bupropion in the central nervous system are similar to nicotine's effects, making low doses of bupropion a suitable option as a nicotine substitute. When used in combination with naltrexone in the marketed product ContraveⓇ for chronic weight management, the two components are thought to have effects on areas of the brain involved in the regulation of food intake. This includes the hypothalamus, which is involved in appetite regulation, and the mesolimbic dopamine circuit, which is involved in reward pathways. Studies have shown that the combined activity of bupropion and naltrexone increase the firing rate of hypothalamic pro-opiomelanocortin (POMC) neurons and blockade of opioid receptor-mediated POMC auto-inhibition, which are associated with a reduction in food intake and increased energy expenditure. This combination was also found to reduce food intake when injected directly into the ventral tegmental area of the mesolimbic circuit in mice, which is an area associated with the regulation of reward pathways. •Mechanism of action (Drug B): Levodopa (L-Dopa) is the gold standard for managing motor and some non-motor symptoms associated with Parkinson's Disease; however, only a small fraction of administered L-Dopa actually crosses the blood-brain barrier to exert its therapeutic action and patients face the risk of developing end-of-dose motor fluctuations, which reflects the rapid peripheral metabolism of L-dopa by aromatic L-amino acid decarboxylase and catechol-O-methyltransferase (COMT). Opicapone is a peripheral, selective, and reversible catechol-O-methyltransferase (COMT) inhibitor. It displays a high binding affinity that is in sub-picomolar ranges, resulting in a slow complex dissociation rate constant and long duration of action in vivo. When opicapone is added to the treatment regimen that contains L-Dopa and DOPA decarboxylase inhibitor, opicapone helps to increase the plasma levels and enhance the therapeutic efficacy of L-Dopa. •Absorption (Drug A): Bupropion is currently available in 3 distinct, but bioequivalent formulations: immediate release (IR), sustained-release (SR), and extended-release (XL). Immediate Release Formulation In humans, following oral administration of bupropion hydrochloride tablets, peak plasma bupropion concentrations are usually achieved within 2 hours. IR formulations provide a short duration of action and are therefore generally dosed three times per day. Sustained Release Formulation In humans, following oral administration of bupropion hydrochloride sustained-release tablets (SR), peak plasma concentration (Cmax) of bupropion is usually achieved within 3 hours. SR formulations provide a 12-hour extended release of medication and are therefore generally dosed twice per day. Extended Release Formulation Following single oral administration of bupropion hydrochloride extended-release tablets (XL) to healthy volunteers, the median time to peak plasma concentrations for bupropion was approximately 5 hours. The presence of food did not affect the peak concentration or area under the curve of bupropion. XL formulations provide a 24-hour extended release of medication and are therefore generally dosed once per day/ In a trial comparing chronic dosing with bupropion hydrochloride extended-release tablets (SR) 150 mg twice daily to bupropion immediate-release formulation 100 mg 3 times daily, the steady state Cmax for bupropion after bupropion hydrochloride sustained-release tablets (SR) administration was approximately 85% of those achieved after bupropion immediate-release formulation administration. Exposure (AUC) to bupropion was equivalent for both formulations. Bioequivalence was also demonstrated for all three major active metabolites (i.e., hydroxybupropion, threohydrobupropion and erythrohydrobupropion) for both Cmax and AUC. Thus, at steady state, bupropion hydrochloride sustained-release tablets (SR) given twice daily, and the immediate-release formulation of bupropion given 3 times daily, are essentially bioequivalent for both bupropion and the 3 quantitatively important metabolites. Furthermore, in a study comparing 14-day dosing with bupropion hydrochloride extended-release tablets (XL), 300 mg once-daily to the immediate-release formulation of bupropion at 100 mg 3 times daily, equivalence was demonstrated for peak plasma concentration and area under the curve for bupropion and the three metabolites (hydroxybupropion, threohydrobupropion, and erythrohydrobupropion). Additionally, in a study comparing 14-day dosing with bupropion hydrochloride extended-release tablets (XL) 300 mg once daily to the sustained-release formulation of bupropion at 150 mg 2 times daily, equivalence was demonstrated for peak plasma concentration and area under the curve for bupropion and the three metabolites. Bupropion hydrochloride extended-release tablets (SR) can be taken with or without food. Bupropion Cmax and AUC were increased by 11% to 35% and 16% to 19%, respectively, when bupropion hydrochloride extended-release tablets (SR) was administered with food to healthy volunteers in three trials. The food effect is not considered clinically significant. Following a single-dose administration of bupropion hydrochloride extended-release tablets (SR) in humans, Cmax of bupropion's metabolite hydroxybupropion occurs approximately 6 hours post-dose and is approximately 10 times the peak level of the parent drug at steady state. The elimination half-life of hydroxybupropion is approximately 20 (±5) hours and its AUC at steady state is about 17 times that of bupropion. The times to peak concentrations for the erythrohydrobupropion and threohydrobupropion metabolites are similar to that of the hydroxybupropion metabolite. However, their elimination half-lives are longer, 33(±10) and 37 (±13) hours, respectively, and steady-state AUCs are 1.5 and 7 times that of bupropion, respectively. •Absorption (Drug B): Orally administered opicapone demonstrates a linear, dose-dependent absorption profile. Opicapone is rapidly absorbed, with an oral bioavailability of about 20%. Following administration of a single 50 mg dose of opicapone, the median T max was two hours, ranging from one to four hours. A moderate fat or moderate calorie meal was shown to decrease the C max by 62%, the mean overall plasma exposure (AUC) by 31%, and the Tmax by 4 hours. •Volume of distribution (Drug A): No volume of distribution available •Volume of distribution (Drug B): Following oral administration, the apparent V d of opicapone at a dose of 50 mg was 29 L with an inter-subject variability of 36%. One study showed small systemic accumulation after multiple-dosing. •Protein binding (Drug A): In vitro tests show that bupropion is 84% bound to human plasma proteins at concentrations up to 200 mcg per mL. The extent of protein binding of the hydroxybupropion metabolite is similar to that for bupropion, whereas the extent of protein binding of the threohydrobupropion metabolite is about half that seen with bupropion. •Protein binding (Drug B): Opicapone is >99% bound to plasma proteins, which is independent of the drug concentration. •Metabolism (Drug A): Bupropion is extensively metabolized in humans. Three metabolites are active: hydroxybupropion, which is formed via hydroxylation of the tert-butyl group of bupropion, and the amino-alcohol isomers, threohydrobupropion and erythrohydrobupropion, which are formed via reduction of the carbonyl group. In vitro findings suggest that CYP2B6 is the principal isoenzyme involved in the formation of hydroxybupropion, while cytochrome P450 enzymes are not involved in the formation of threohydrobupropion. Hydroxybupropion has been shown to have the same affinity as bupropion for the norepinephrine transporter (NET) but approximately 50% of its antidepressant activity despite reaching concentrations of ~10-fold higher than that of the parent drug. Oxidation of the bupropion side chain results in the formation of a glycine conjugate of meta-chlorobenzoic acid, which is then excreted as the major urinary metabolite. The potency and toxicity of the metabolites relative to bupropion have not been fully characterized. However, it has been demonstrated in an antidepressant screening test in mice that hydroxybupropion is one-half as potent as bupropion, while threohydrobupropion and erythrohydrobupropion are 5-fold less potent than bupropion. This may be of clinical importance because the plasma concentrations of the metabolites are as high as or higher than those of bupropion. Bupropion and its metabolites exhibit linear kinetics following chronic administration of 300 to 450 mg per day. •Metabolism (Drug B): According to clinical and in vitro studies, sulphation is the primary metabolic pathway of opicapone, forming the inactive metabolite. Opicapone can also undergo glucuronidation, COMT-mediated methylation, reduction, and glutathione conjugation. As two major circulating metabolites, BIA 9-1103 (3-O-sulphated opicapone) accounts for 67.1% of the total radioactivity and BIA 9-1104 (4-O-methylated opicapone) accounts for 20.5% of the total radioactivity. Other metabolites are generally unquantifiable in plasma samples. Opicapone can undergo N-oxide reduction to form BIA 9-1079, which was shown to be an active metabolite in non-clinical studies; however, it is generally undetectable in humans. Other inactive metabolites include BIA 9-1100, BIA 9-1101, and BIA 9-1106. •Route of elimination (Drug A): Bupropion is extensively metabolized in humans. Oxidation of the bupropion side chain results in the formation of a glycine conjugate of metachlorobenzoic acid, which is then excreted as the major urinary metabolite. Following oral administration of 200 mg of 14C-bupropion in humans, 87% and 10% of the radioactive dose were recovered in the urine and feces, respectively. However, the fraction of the oral dose of bupropion excreted unchanged was only 0.5%, a finding consistent with the extensive metabolism of bupropion. •Route of elimination (Drug B): Following administration of a single 100 mg dose of radiolabeled opicapone in healthy subjects, about 70% of the total dose was recovered in feces, where 22% of the recovered dose was excreted as an unchanged parent drug. About 20% of the total dose was recovered in exhaled air and about 5% was recovered in the urine, where less than 1% of the recovered dose was in an unchanged form. The primary detectable metabolite in the urine was the glucuronide metabolite. •Half-life (Drug A): 24 hours •Half-life (Drug B): The mean elimination half-life of opicapone is one to two hours. Despite the short half-life, the observed half-life of opicapone-induced COMT inhibition in human red blood cells was 61.6 hours with a standard deviation of 37.6 hours. •Clearance (Drug A): No clearance available •Clearance (Drug B): Following oral administration of 50 mg opicapone, the apparent total body clearance was 22 L/h, with an inter-subject variability of 45%. •Toxicity (Drug A): Symptoms of overdose include seizures, hallucinations, loss of consciousness, tachycardia, and cardiac arrest. •Toxicity (Drug B): There is no reported LD 50 data of opicapone. As there is no known antidote for opicapone overdose, overdosage should be managed with symptomatic and supportive treatment. Removal of the drug through gastric lavage and/or inactivation by administering activated charcoal should be considered. •Brand Names (Drug A): Aplenzin, Auvelity, Budeprion, Contrave, Forfivo, Wellbutrin, Zyban •Brand Names (Drug B): Ongentys •Synonyms (Drug A): No synonyms listed •Synonyms (Drug B): No synonyms listed •Summary (Drug A): Bupropion is a norepinephrine and dopamine reuptake inhibitor used in the treatment of major depressive disorder (MDD), seasonal affective disorder (SAD), and as an aid to smoking cessation. •Summary (Drug B): Opicapone is a catechol-O-methyltransferase inhibitor used as an adjunct treatment for Parkinson's Disease in adults currently receiving levodopa and a dopa decarboxylase inhibitor. Output: Despite the fact that these drugs are sometimes used in combination to treat depression in Parkinson's disease3, the administration of bupropion with anti-Parkinson drugs may lead to central nervous system toxicity. Bupropion is considered a norepinephrine-dopamine reuptake inhibitor, is found to occupy the DAT dopamine transporter, and acts as a dopamine agonist. Additive effects of these dopaminergic drugs may produce excess dopaminergic activity. Agitation, restlessness, tremor, ataxia, gait disturbance, and dizziness are some examples of effects that may occur from concurrent administration. The severity of the interaction is moderate.

Does Bupropion and Opium interact?

•Drug A: Bupropion •Drug B: Opium •Severity: MAJOR •Description: The metabolism of Opium can be decreased when combined with Bupropion. •Extended Description: The subject drug is a strong CYP2D6 inhibitor and the affected drug is metabolized by CYP2D6. Concomitant administration may decrease the metabolism of the affected drug, which could increase serum concentrations as well as the risk and severity of adverse effects. •Indication (Drug A): Bupropion is indicated for the treatment of major depressive disorder (MDD), seasonal affective disorder (SAD), and as an aid to smoking cessation. When used in combination with naltrexone as the marketed product ContraveⓇ, bupropion is indicated as an adjunct to a reduced-calorie diet and increased physical activity for chronic weight management in adults with an initial body mass index (BMI) of: 30 kg/m^2 or greater (obese) or 27 kg/m^2 or greater (overweight) in the presence of at least one weight-related comorbid condition (e.g., hypertension, type 2 diabetes mellitus, or dyslipidemia). Bupropion is also used off-label as a first-line treatment in patients with ADHD and comorbid bipolar disorder when used as an adjunct to mood stabilizers. •Indication (Drug B): Opium and its derivatives are the most commonly used medications for the treatment of acute and chronic pain. Opium and its alkaloid-derivatives can also be used as tranquilizers, antitussives and in the treatment of diarrhea. The direct use of opium is not common nowadays but the use of some of its derivatives such as morphine and codeine, as well as the use of a tincture of opium for severe diarrhea can be seen in medical practice. Illegal use of opium has been registered to be for both recreational and medicinal purposes. •Pharmacodynamics (Drug A): Bupropion is chemically unrelated to tricyclic, tetracyclic, selective serotonin re-uptake inhibitors, or other known antidepressant agents. Compared to classical tricyclic antidepressants, Bupropion is a relatively weak inhibitor of the neuronal uptake of norepinephrine and dopamine. In addition, Bupropion does not inhibit monoamine oxidase. Bupropion has been found to be essentially inactive at the serotonin transporter (SERT)(IC50 >10 000 nM), however both bupropion and its primary metabolite hydroxybupropion have been found to block the function of cation-selective serotonin type 3A receptors (5-HT3ARs). Bupropion produces dose-related central nervous system (CNS) stimulant effects in animals, as evidenced by increased locomotor activity, increased rates of responding in various schedule-controlled operant behaviour tasks, and, at high doses, induction of mild stereotyped behaviour. Due to these stimulant effects and selective activity at dopamine and norepinephrine receptors, bupropion has been identified as having an abuse potential. Bupropion has a similar structure to the controlled substance Cathinone, and has been identified as having mild amphetamine-like activity, particularly when inhaled or injected. Bupropion is also known to lower the seizure threshold, making any pre-existing seizure conditions a contraindication to its use. This risk is exacerbated when bupropion is combined with other drugs or substances that lower the seizure threshold, such as cocaine, or in clinical situations that would increase the risk of a seizure such as abrupt alcohol or benzodiazepine withdrawal. As norepinephrine has been shown to have anticonvulsant properties, bupropion's inhibitory effects on NET are thought to contribute to its pro-convulsant activity. Bupropion has been shown to increase blood pressure and pose a risk for exacerbation of unmanaged or pre-existing hypertension, however, clinical trials of bupropion in smokers with CVD have not identified an increased incidence of CV events including stroke or heart attack. In clinical trials, the mean increase in systolic blood pressure associated with the use of bupropion was found to be 1.3 mmHg. •Pharmacodynamics (Drug B): Opioids can reduce the intensity and unpleasant feeling of pain. The unspecific effect of opium to the different opioid receptors produce the generation of various effects such as sedation, euphoria, dysphoria, respiratory depression, constipation, pruritus, nausea, and vomiting. It is reported that the secondary effects tend to be diminished as long-term use tolerance is developed. Some reports have also shown an opioid-driven impairment of the hypothalamic function that can result in a loss of libido, impotence, and infertility. Patients have reported a sensation of stress relief even in presence of pain as well as the presence of sedation, hypoventilation, cough inhibition, prolonged apnea, myosis and respiratory obstruction. In the cardiovascular system, there are reports of peripheral vasodilatation, including cutaneous causing flushing of the face, neck, and thorax, impaired sympathetic reflexes and postural hypotension. In the gastrointestinal and urogenital system, the increase in smooth muscle tone has been shown to produce reduced peristalsis, delayed gastric emptying and urinary retention. •Mechanism of action (Drug A): Bupropion is a norepinephrine/dopamine-reuptake inhibitor (NDRI) that exerts its pharmacological effects by weakly inhibiting the enzymes involved in the uptake of the neurotransmitters norepinephrine and dopamine from the synaptic cleft, therefore prolonging their duration of action within the neuronal synapse and the downstream effects of these neurotransmitters. More specifically, bupropion binds to the norepinephrine transporter (NET) and the dopamine transporter (DAT). Bupropion was originally classified as an "atypical" antidepressant because it does not exert the same effects as the classical antidepressants such as Monoamine Oxidase Inhibitors (MAOIs), Tricyclic Antidepressants (TCAs), or Selective Serotonin Reuptake Inhibitors (SSRIs). While it has comparable effectiveness to typical first-line options for the treatment of depression such as SSRIs, bupropion is a unique option for the treatment of MDD as it lacks any clinically relevant serotonergic effects, typical of other mood medications, or any effects on histamine or adrenaline receptors. Lack of activity at these receptors results in a more tolerable side effect profile; bupropion is less likely to cause sexual side effects, sedation, or weight gain as compared to SSRIs or TCAs, for example. When used as an aid to smoking cessation, bupropion is thought to confer its anti-craving and anti-withdrawal effects by inhibiting dopamine reuptake, which is thought to be involved in the reward pathways associated with nicotine, and through the antagonism of the nicotinic acetylcholinergic receptor (AChR), thereby blunting the effects of nicotine. Furthermore, the stimulatory effects produced by bupropion in the central nervous system are similar to nicotine's effects, making low doses of bupropion a suitable option as a nicotine substitute. When used in combination with naltrexone in the marketed product ContraveⓇ for chronic weight management, the two components are thought to have effects on areas of the brain involved in the regulation of food intake. This includes the hypothalamus, which is involved in appetite regulation, and the mesolimbic dopamine circuit, which is involved in reward pathways. Studies have shown that the combined activity of bupropion and naltrexone increase the firing rate of hypothalamic pro-opiomelanocortin (POMC) neurons and blockade of opioid receptor-mediated POMC auto-inhibition, which are associated with a reduction in food intake and increased energy expenditure. This combination was also found to reduce food intake when injected directly into the ventral tegmental area of the mesolimbic circuit in mice, which is an area associated with the regulation of reward pathways. •Mechanism of action (Drug B): Opium produces its effects by activating specific G protein-coupled receptors in the brain, spinal cord, and peripheral nervous system. There are three major classes of opioid receptors being δ-opioid, κ-opioid and μ-opioid. Opium will generate an agonist activity which will later open the potassium channels and prevent the opening of voltage-gated calcium channels. This activity causes a reduction in neuronal excitability and inhibits the release of pain neurotransmitters. The addictive character of opium is related to the binding to the μ-opioid receptors, which will activate dopaminergic neurons in the ventral tegmental area of the midbrain and thus, enhance the dopamine release in the nucleus accumbens. This mechanism involves the reward activity of the mesolimbic dopaminergic pathway. •Absorption (Drug A): Bupropion is currently available in 3 distinct, but bioequivalent formulations: immediate release (IR), sustained-release (SR), and extended-release (XL). Immediate Release Formulation In humans, following oral administration of bupropion hydrochloride tablets, peak plasma bupropion concentrations are usually achieved within 2 hours. IR formulations provide a short duration of action and are therefore generally dosed three times per day. Sustained Release Formulation In humans, following oral administration of bupropion hydrochloride sustained-release tablets (SR), peak plasma concentration (Cmax) of bupropion is usually achieved within 3 hours. SR formulations provide a 12-hour extended release of medication and are therefore generally dosed twice per day. Extended Release Formulation Following single oral administration of bupropion hydrochloride extended-release tablets (XL) to healthy volunteers, the median time to peak plasma concentrations for bupropion was approximately 5 hours. The presence of food did not affect the peak concentration or area under the curve of bupropion. XL formulations provide a 24-hour extended release of medication and are therefore generally dosed once per day/ In a trial comparing chronic dosing with bupropion hydrochloride extended-release tablets (SR) 150 mg twice daily to bupropion immediate-release formulation 100 mg 3 times daily, the steady state Cmax for bupropion after bupropion hydrochloride sustained-release tablets (SR) administration was approximately 85% of those achieved after bupropion immediate-release formulation administration. Exposure (AUC) to bupropion was equivalent for both formulations. Bioequivalence was also demonstrated for all three major active metabolites (i.e., hydroxybupropion, threohydrobupropion and erythrohydrobupropion) for both Cmax and AUC. Thus, at steady state, bupropion hydrochloride sustained-release tablets (SR) given twice daily, and the immediate-release formulation of bupropion given 3 times daily, are essentially bioequivalent for both bupropion and the 3 quantitatively important metabolites. Furthermore, in a study comparing 14-day dosing with bupropion hydrochloride extended-release tablets (XL), 300 mg once-daily to the immediate-release formulation of bupropion at 100 mg 3 times daily, equivalence was demonstrated for peak plasma concentration and area under the curve for bupropion and the three metabolites (hydroxybupropion, threohydrobupropion, and erythrohydrobupropion). Additionally, in a study comparing 14-day dosing with bupropion hydrochloride extended-release tablets (XL) 300 mg once daily to the sustained-release formulation of bupropion at 150 mg 2 times daily, equivalence was demonstrated for peak plasma concentration and area under the curve for bupropion and the three metabolites. Bupropion hydrochloride extended-release tablets (SR) can be taken with or without food. Bupropion Cmax and AUC were increased by 11% to 35% and 16% to 19%, respectively, when bupropion hydrochloride extended-release tablets (SR) was administered with food to healthy volunteers in three trials. The food effect is not considered clinically significant. Following a single-dose administration of bupropion hydrochloride extended-release tablets (SR) in humans, Cmax of bupropion's metabolite hydroxybupropion occurs approximately 6 hours post-dose and is approximately 10 times the peak level of the parent drug at steady state. The elimination half-life of hydroxybupropion is approximately 20 (±5) hours and its AUC at steady state is about 17 times that of bupropion. The times to peak concentrations for the erythrohydrobupropion and threohydrobupropion metabolites are similar to that of the hydroxybupropion metabolite. However, their elimination half-lives are longer, 33(±10) and 37 (±13) hours, respectively, and steady-state AUCs are 1.5 and 7 times that of bupropion, respectively. •Absorption (Drug B): After oral administration, opium bioavailability is poor. In the form of opioid tincture, the Cmax and AUC of opium are between 16-24 mg/ml and 3237-6727 ng/ml.h, respectively. •Volume of distribution (Drug A): No volume of distribution available •Volume of distribution (Drug B): Opium presents a large volume of distribution that exceeds the total body water. •Protein binding (Drug A): In vitro tests show that bupropion is 84% bound to human plasma proteins at concentrations up to 200 mcg per mL. The extent of protein binding of the hydroxybupropion metabolite is similar to that for bupropion, whereas the extent of protein binding of the threohydrobupropion metabolite is about half that seen with bupropion. •Protein binding (Drug B): The protein binding of the alkaloids that form opium, such as morphine and codeine, can range from 20-60% depending on the specific alkaloid. The highest binding proteins for opium alkaloids are albumin and beta-globulin II. •Metabolism (Drug A): Bupropion is extensively metabolized in humans. Three metabolites are active: hydroxybupropion, which is formed via hydroxylation of the tert-butyl group of bupropion, and the amino-alcohol isomers, threohydrobupropion and erythrohydrobupropion, which are formed via reduction of the carbonyl group. In vitro findings suggest that CYP2B6 is the principal isoenzyme involved in the formation of hydroxybupropion, while cytochrome P450 enzymes are not involved in the formation of threohydrobupropion. Hydroxybupropion has been shown to have the same affinity as bupropion for the norepinephrine transporter (NET) but approximately 50% of its antidepressant activity despite reaching concentrations of ~10-fold higher than that of the parent drug. Oxidation of the bupropion side chain results in the formation of a glycine conjugate of meta-chlorobenzoic acid, which is then excreted as the major urinary metabolite. The potency and toxicity of the metabolites relative to bupropion have not been fully characterized. However, it has been demonstrated in an antidepressant screening test in mice that hydroxybupropion is one-half as potent as bupropion, while threohydrobupropion and erythrohydrobupropion are 5-fold less potent than bupropion. This may be of clinical importance because the plasma concentrations of the metabolites are as high as or higher than those of bupropion. Bupropion and its metabolites exhibit linear kinetics following chronic administration of 300 to 450 mg per day. •Metabolism (Drug B): Opium contains 50 different alkaloid opiates. The most common metabolism of opiates is to be ultimately converted to morphine which is further converted to morphine-3,6-diglucuronide. Opioids are metabolized vastly by the enzyme CYP 2D6 and any mutation in this kind of enzyme or coadministration with drugs that interfere with this enzyme may generate a change in the metabolism speed. For years, because of this metabolism pathway, it was very hard to differentiate between illicit heroin users and involuntary exposure to poppy seeds. The original tests for this differentiations were based in the presence of morphine in urine without evidence of 6-monoacetylmorphine. Now it is known the presence of a glucuronide metabolite only in the consumption of heroin called ATM4G and this allows a clear differentiation of the consumption of illegal heroin and poppy seed ingestion. •Route of elimination (Drug A): Bupropion is extensively metabolized in humans. Oxidation of the bupropion side chain results in the formation of a glycine conjugate of metachlorobenzoic acid, which is then excreted as the major urinary metabolite. Following oral administration of 200 mg of 14C-bupropion in humans, 87% and 10% of the radioactive dose were recovered in the urine and feces, respectively. However, the fraction of the oral dose of bupropion excreted unchanged was only 0.5%, a finding consistent with the extensive metabolism of bupropion. •Route of elimination (Drug B): Opium is a mixture of different alkaloids including morphine and codeine. After a single ingestion of opium preparations, codeine and morphine can be found excreted in urine. The presence of codeine and morphine in urine seems to be detectable 2-12 hours and 2-36 hours post administration, respectively. The urinary excretion of morphine and codeine seems to be longer as the dose of opium is increased. After multiple dosages of opium, the presence of codeine and morphine in urine could be detected even after 48 and 84 hours post administration, respectively. After ingestion of poppy seeds, it is possible to collect morphine and codeine in urine 3-25 hours and 3-22 hours after administration, respectively. •Half-life (Drug A): 24 hours •Half-life (Drug B): The half-life of opium ranges between 3-10 hours. •Clearance (Drug A): No clearance available •Clearance (Drug B): No clearance available •Toxicity (Drug A): Symptoms of overdose include seizures, hallucinations, loss of consciousness, tachycardia, and cardiac arrest. •Toxicity (Drug B): Some toxicity concerns from the consumption of opium are the generation of addiction, physical dependence and tolerance to the effect. Studies regarding the opioid tolerance in the treatment of chronic pain have not been systematically investigated. There are also concerns about the opioid-driven modification of endocrine function, currently reported as lower testosterone levels, loss of libido, amenorrhea and infertility. •Brand Names (Drug A): Aplenzin, Auvelity, Budeprion, Contrave, Forfivo, Wellbutrin, Zyban •Brand Names (Drug B): No brand names available •Synonyms (Drug A): No synonyms listed •Synonyms (Drug B): No synonyms listed •Summary (Drug A): Bupropion is a norepinephrine and dopamine reuptake inhibitor used in the treatment of major depressive disorder (MDD), seasonal affective disorder (SAD), and as an aid to smoking cessation. •Summary (Drug B): Opium is a medication used to treat moderate to severe pain.

The subject drug is a strong CYP2D6 inhibitor and the affected drug is metabolized by CYP2D6. Concomitant administration may decrease the metabolism of the affected drug, which could increase serum concentrations as well as the risk and severity of adverse effects. The severity of the interaction is major.

Question: Does Bupropion and Opium interact? Information: •Drug A: Bupropion •Drug B: Opium •Severity: MAJOR •Description: The metabolism of Opium can be decreased when combined with Bupropion. •Extended Description: The subject drug is a strong CYP2D6 inhibitor and the affected drug is metabolized by CYP2D6. Concomitant administration may decrease the metabolism of the affected drug, which could increase serum concentrations as well as the risk and severity of adverse effects. •Indication (Drug A): Bupropion is indicated for the treatment of major depressive disorder (MDD), seasonal affective disorder (SAD), and as an aid to smoking cessation. When used in combination with naltrexone as the marketed product ContraveⓇ, bupropion is indicated as an adjunct to a reduced-calorie diet and increased physical activity for chronic weight management in adults with an initial body mass index (BMI) of: 30 kg/m^2 or greater (obese) or 27 kg/m^2 or greater (overweight) in the presence of at least one weight-related comorbid condition (e.g., hypertension, type 2 diabetes mellitus, or dyslipidemia). Bupropion is also used off-label as a first-line treatment in patients with ADHD and comorbid bipolar disorder when used as an adjunct to mood stabilizers. •Indication (Drug B): Opium and its derivatives are the most commonly used medications for the treatment of acute and chronic pain. Opium and its alkaloid-derivatives can also be used as tranquilizers, antitussives and in the treatment of diarrhea. The direct use of opium is not common nowadays but the use of some of its derivatives such as morphine and codeine, as well as the use of a tincture of opium for severe diarrhea can be seen in medical practice. Illegal use of opium has been registered to be for both recreational and medicinal purposes. •Pharmacodynamics (Drug A): Bupropion is chemically unrelated to tricyclic, tetracyclic, selective serotonin re-uptake inhibitors, or other known antidepressant agents. Compared to classical tricyclic antidepressants, Bupropion is a relatively weak inhibitor of the neuronal uptake of norepinephrine and dopamine. In addition, Bupropion does not inhibit monoamine oxidase. Bupropion has been found to be essentially inactive at the serotonin transporter (SERT)(IC50 >10 000 nM), however both bupropion and its primary metabolite hydroxybupropion have been found to block the function of cation-selective serotonin type 3A receptors (5-HT3ARs). Bupropion produces dose-related central nervous system (CNS) stimulant effects in animals, as evidenced by increased locomotor activity, increased rates of responding in various schedule-controlled operant behaviour tasks, and, at high doses, induction of mild stereotyped behaviour. Due to these stimulant effects and selective activity at dopamine and norepinephrine receptors, bupropion has been identified as having an abuse potential. Bupropion has a similar structure to the controlled substance Cathinone, and has been identified as having mild amphetamine-like activity, particularly when inhaled or injected. Bupropion is also known to lower the seizure threshold, making any pre-existing seizure conditions a contraindication to its use. This risk is exacerbated when bupropion is combined with other drugs or substances that lower the seizure threshold, such as cocaine, or in clinical situations that would increase the risk of a seizure such as abrupt alcohol or benzodiazepine withdrawal. As norepinephrine has been shown to have anticonvulsant properties, bupropion's inhibitory effects on NET are thought to contribute to its pro-convulsant activity. Bupropion has been shown to increase blood pressure and pose a risk for exacerbation of unmanaged or pre-existing hypertension, however, clinical trials of bupropion in smokers with CVD have not identified an increased incidence of CV events including stroke or heart attack. In clinical trials, the mean increase in systolic blood pressure associated with the use of bupropion was found to be 1.3 mmHg. •Pharmacodynamics (Drug B): Opioids can reduce the intensity and unpleasant feeling of pain. The unspecific effect of opium to the different opioid receptors produce the generation of various effects such as sedation, euphoria, dysphoria, respiratory depression, constipation, pruritus, nausea, and vomiting. It is reported that the secondary effects tend to be diminished as long-term use tolerance is developed. Some reports have also shown an opioid-driven impairment of the hypothalamic function that can result in a loss of libido, impotence, and infertility. Patients have reported a sensation of stress relief even in presence of pain as well as the presence of sedation, hypoventilation, cough inhibition, prolonged apnea, myosis and respiratory obstruction. In the cardiovascular system, there are reports of peripheral vasodilatation, including cutaneous causing flushing of the face, neck, and thorax, impaired sympathetic reflexes and postural hypotension. In the gastrointestinal and urogenital system, the increase in smooth muscle tone has been shown to produce reduced peristalsis, delayed gastric emptying and urinary retention. •Mechanism of action (Drug A): Bupropion is a norepinephrine/dopamine-reuptake inhibitor (NDRI) that exerts its pharmacological effects by weakly inhibiting the enzymes involved in the uptake of the neurotransmitters norepinephrine and dopamine from the synaptic cleft, therefore prolonging their duration of action within the neuronal synapse and the downstream effects of these neurotransmitters. More specifically, bupropion binds to the norepinephrine transporter (NET) and the dopamine transporter (DAT). Bupropion was originally classified as an "atypical" antidepressant because it does not exert the same effects as the classical antidepressants such as Monoamine Oxidase Inhibitors (MAOIs), Tricyclic Antidepressants (TCAs), or Selective Serotonin Reuptake Inhibitors (SSRIs). While it has comparable effectiveness to typical first-line options for the treatment of depression such as SSRIs, bupropion is a unique option for the treatment of MDD as it lacks any clinically relevant serotonergic effects, typical of other mood medications, or any effects on histamine or adrenaline receptors. Lack of activity at these receptors results in a more tolerable side effect profile; bupropion is less likely to cause sexual side effects, sedation, or weight gain as compared to SSRIs or TCAs, for example. When used as an aid to smoking cessation, bupropion is thought to confer its anti-craving and anti-withdrawal effects by inhibiting dopamine reuptake, which is thought to be involved in the reward pathways associated with nicotine, and through the antagonism of the nicotinic acetylcholinergic receptor (AChR), thereby blunting the effects of nicotine. Furthermore, the stimulatory effects produced by bupropion in the central nervous system are similar to nicotine's effects, making low doses of bupropion a suitable option as a nicotine substitute. When used in combination with naltrexone in the marketed product ContraveⓇ for chronic weight management, the two components are thought to have effects on areas of the brain involved in the regulation of food intake. This includes the hypothalamus, which is involved in appetite regulation, and the mesolimbic dopamine circuit, which is involved in reward pathways. Studies have shown that the combined activity of bupropion and naltrexone increase the firing rate of hypothalamic pro-opiomelanocortin (POMC) neurons and blockade of opioid receptor-mediated POMC auto-inhibition, which are associated with a reduction in food intake and increased energy expenditure. This combination was also found to reduce food intake when injected directly into the ventral tegmental area of the mesolimbic circuit in mice, which is an area associated with the regulation of reward pathways. •Mechanism of action (Drug B): Opium produces its effects by activating specific G protein-coupled receptors in the brain, spinal cord, and peripheral nervous system. There are three major classes of opioid receptors being δ-opioid, κ-opioid and μ-opioid. Opium will generate an agonist activity which will later open the potassium channels and prevent the opening of voltage-gated calcium channels. This activity causes a reduction in neuronal excitability and inhibits the release of pain neurotransmitters. The addictive character of opium is related to the binding to the μ-opioid receptors, which will activate dopaminergic neurons in the ventral tegmental area of the midbrain and thus, enhance the dopamine release in the nucleus accumbens. This mechanism involves the reward activity of the mesolimbic dopaminergic pathway. •Absorption (Drug A): Bupropion is currently available in 3 distinct, but bioequivalent formulations: immediate release (IR), sustained-release (SR), and extended-release (XL). Immediate Release Formulation In humans, following oral administration of bupropion hydrochloride tablets, peak plasma bupropion concentrations are usually achieved within 2 hours. IR formulations provide a short duration of action and are therefore generally dosed three times per day. Sustained Release Formulation In humans, following oral administration of bupropion hydrochloride sustained-release tablets (SR), peak plasma concentration (Cmax) of bupropion is usually achieved within 3 hours. SR formulations provide a 12-hour extended release of medication and are therefore generally dosed twice per day. Extended Release Formulation Following single oral administration of bupropion hydrochloride extended-release tablets (XL) to healthy volunteers, the median time to peak plasma concentrations for bupropion was approximately 5 hours. The presence of food did not affect the peak concentration or area under the curve of bupropion. XL formulations provide a 24-hour extended release of medication and are therefore generally dosed once per day/ In a trial comparing chronic dosing with bupropion hydrochloride extended-release tablets (SR) 150 mg twice daily to bupropion immediate-release formulation 100 mg 3 times daily, the steady state Cmax for bupropion after bupropion hydrochloride sustained-release tablets (SR) administration was approximately 85% of those achieved after bupropion immediate-release formulation administration. Exposure (AUC) to bupropion was equivalent for both formulations. Bioequivalence was also demonstrated for all three major active metabolites (i.e., hydroxybupropion, threohydrobupropion and erythrohydrobupropion) for both Cmax and AUC. Thus, at steady state, bupropion hydrochloride sustained-release tablets (SR) given twice daily, and the immediate-release formulation of bupropion given 3 times daily, are essentially bioequivalent for both bupropion and the 3 quantitatively important metabolites. Furthermore, in a study comparing 14-day dosing with bupropion hydrochloride extended-release tablets (XL), 300 mg once-daily to the immediate-release formulation of bupropion at 100 mg 3 times daily, equivalence was demonstrated for peak plasma concentration and area under the curve for bupropion and the three metabolites (hydroxybupropion, threohydrobupropion, and erythrohydrobupropion). Additionally, in a study comparing 14-day dosing with bupropion hydrochloride extended-release tablets (XL) 300 mg once daily to the sustained-release formulation of bupropion at 150 mg 2 times daily, equivalence was demonstrated for peak plasma concentration and area under the curve for bupropion and the three metabolites. Bupropion hydrochloride extended-release tablets (SR) can be taken with or without food. Bupropion Cmax and AUC were increased by 11% to 35% and 16% to 19%, respectively, when bupropion hydrochloride extended-release tablets (SR) was administered with food to healthy volunteers in three trials. The food effect is not considered clinically significant. Following a single-dose administration of bupropion hydrochloride extended-release tablets (SR) in humans, Cmax of bupropion's metabolite hydroxybupropion occurs approximately 6 hours post-dose and is approximately 10 times the peak level of the parent drug at steady state. The elimination half-life of hydroxybupropion is approximately 20 (±5) hours and its AUC at steady state is about 17 times that of bupropion. The times to peak concentrations for the erythrohydrobupropion and threohydrobupropion metabolites are similar to that of the hydroxybupropion metabolite. However, their elimination half-lives are longer, 33(±10) and 37 (±13) hours, respectively, and steady-state AUCs are 1.5 and 7 times that of bupropion, respectively. •Absorption (Drug B): After oral administration, opium bioavailability is poor. In the form of opioid tincture, the Cmax and AUC of opium are between 16-24 mg/ml and 3237-6727 ng/ml.h, respectively. •Volume of distribution (Drug A): No volume of distribution available •Volume of distribution (Drug B): Opium presents a large volume of distribution that exceeds the total body water. •Protein binding (Drug A): In vitro tests show that bupropion is 84% bound to human plasma proteins at concentrations up to 200 mcg per mL. The extent of protein binding of the hydroxybupropion metabolite is similar to that for bupropion, whereas the extent of protein binding of the threohydrobupropion metabolite is about half that seen with bupropion. •Protein binding (Drug B): The protein binding of the alkaloids that form opium, such as morphine and codeine, can range from 20-60% depending on the specific alkaloid. The highest binding proteins for opium alkaloids are albumin and beta-globulin II. •Metabolism (Drug A): Bupropion is extensively metabolized in humans. Three metabolites are active: hydroxybupropion, which is formed via hydroxylation of the tert-butyl group of bupropion, and the amino-alcohol isomers, threohydrobupropion and erythrohydrobupropion, which are formed via reduction of the carbonyl group. In vitro findings suggest that CYP2B6 is the principal isoenzyme involved in the formation of hydroxybupropion, while cytochrome P450 enzymes are not involved in the formation of threohydrobupropion. Hydroxybupropion has been shown to have the same affinity as bupropion for the norepinephrine transporter (NET) but approximately 50% of its antidepressant activity despite reaching concentrations of ~10-fold higher than that of the parent drug. Oxidation of the bupropion side chain results in the formation of a glycine conjugate of meta-chlorobenzoic acid, which is then excreted as the major urinary metabolite. The potency and toxicity of the metabolites relative to bupropion have not been fully characterized. However, it has been demonstrated in an antidepressant screening test in mice that hydroxybupropion is one-half as potent as bupropion, while threohydrobupropion and erythrohydrobupropion are 5-fold less potent than bupropion. This may be of clinical importance because the plasma concentrations of the metabolites are as high as or higher than those of bupropion. Bupropion and its metabolites exhibit linear kinetics following chronic administration of 300 to 450 mg per day. •Metabolism (Drug B): Opium contains 50 different alkaloid opiates. The most common metabolism of opiates is to be ultimately converted to morphine which is further converted to morphine-3,6-diglucuronide. Opioids are metabolized vastly by the enzyme CYP 2D6 and any mutation in this kind of enzyme or coadministration with drugs that interfere with this enzyme may generate a change in the metabolism speed. For years, because of this metabolism pathway, it was very hard to differentiate between illicit heroin users and involuntary exposure to poppy seeds. The original tests for this differentiations were based in the presence of morphine in urine without evidence of 6-monoacetylmorphine. Now it is known the presence of a glucuronide metabolite only in the consumption of heroin called ATM4G and this allows a clear differentiation of the consumption of illegal heroin and poppy seed ingestion. •Route of elimination (Drug A): Bupropion is extensively metabolized in humans. Oxidation of the bupropion side chain results in the formation of a glycine conjugate of metachlorobenzoic acid, which is then excreted as the major urinary metabolite. Following oral administration of 200 mg of 14C-bupropion in humans, 87% and 10% of the radioactive dose were recovered in the urine and feces, respectively. However, the fraction of the oral dose of bupropion excreted unchanged was only 0.5%, a finding consistent with the extensive metabolism of bupropion. •Route of elimination (Drug B): Opium is a mixture of different alkaloids including morphine and codeine. After a single ingestion of opium preparations, codeine and morphine can be found excreted in urine. The presence of codeine and morphine in urine seems to be detectable 2-12 hours and 2-36 hours post administration, respectively. The urinary excretion of morphine and codeine seems to be longer as the dose of opium is increased. After multiple dosages of opium, the presence of codeine and morphine in urine could be detected even after 48 and 84 hours post administration, respectively. After ingestion of poppy seeds, it is possible to collect morphine and codeine in urine 3-25 hours and 3-22 hours after administration, respectively. •Half-life (Drug A): 24 hours •Half-life (Drug B): The half-life of opium ranges between 3-10 hours. •Clearance (Drug A): No clearance available •Clearance (Drug B): No clearance available •Toxicity (Drug A): Symptoms of overdose include seizures, hallucinations, loss of consciousness, tachycardia, and cardiac arrest. •Toxicity (Drug B): Some toxicity concerns from the consumption of opium are the generation of addiction, physical dependence and tolerance to the effect. Studies regarding the opioid tolerance in the treatment of chronic pain have not been systematically investigated. There are also concerns about the opioid-driven modification of endocrine function, currently reported as lower testosterone levels, loss of libido, amenorrhea and infertility. •Brand Names (Drug A): Aplenzin, Auvelity, Budeprion, Contrave, Forfivo, Wellbutrin, Zyban •Brand Names (Drug B): No brand names available •Synonyms (Drug A): No synonyms listed •Synonyms (Drug B): No synonyms listed •Summary (Drug A): Bupropion is a norepinephrine and dopamine reuptake inhibitor used in the treatment of major depressive disorder (MDD), seasonal affective disorder (SAD), and as an aid to smoking cessation. •Summary (Drug B): Opium is a medication used to treat moderate to severe pain. Output: The subject drug is a strong CYP2D6 inhibitor and the affected drug is metabolized by CYP2D6. Concomitant administration may decrease the metabolism of the affected drug, which could increase serum concentrations as well as the risk and severity of adverse effects. The severity of the interaction is major.

Does Bupropion and Oritavancin interact?

•Drug A: Bupropion •Drug B: Oritavancin •Severity: MINOR •Description: The metabolism of Bupropion can be decreased when combined with Oritavancin. •Extended Description: The subject drug is known to be a weak inhibitor of CYP2C9 while the affected drug is reported to be metabolized by CYP2C9. Concomitant administration of these agents can cause an increase in the serum concentration of the affected drug due to decreased metabolism by CYP2C9, which may result in increased incidence and/or severity of adverse effects related to the affected drug. •Indication (Drug A): Bupropion is indicated for the treatment of major depressive disorder (MDD), seasonal affective disorder (SAD), and as an aid to smoking cessation. When used in combination with naltrexone as the marketed product ContraveⓇ, bupropion is indicated as an adjunct to a reduced-calorie diet and increased physical activity for chronic weight management in adults with an initial body mass index (BMI) of: 30 kg/m^2 or greater (obese) or 27 kg/m^2 or greater (overweight) in the presence of at least one weight-related comorbid condition (e.g., hypertension, type 2 diabetes mellitus, or dyslipidemia). Bupropion is also used off-label as a first-line treatment in patients with ADHD and comorbid bipolar disorder when used as an adjunct to mood stabilizers. •Indication (Drug B): Oritavancin is indicated for the treatment of adult patients with acute bacterial skin and skin structure (including subcutaneous) infection. It is used for confirmed/suspected infections with designated and susceptible gram-positive organisms. There are two preparations of oritavancin; the 400 mg dose that is administered over 3 hours, and the 1200 mg dose administered over 1 hour. Both are indicated for susceptible gram-positive skin and skin structure infections in adults. As antimicrobial susceptibility patterns are geographically distinct, local antibiograms should be consulted to ensure adequate coverage of relevant pathogens prior to use. •Pharmacodynamics (Drug A): Bupropion is chemically unrelated to tricyclic, tetracyclic, selective serotonin re-uptake inhibitors, or other known antidepressant agents. Compared to classical tricyclic antidepressants, Bupropion is a relatively weak inhibitor of the neuronal uptake of norepinephrine and dopamine. In addition, Bupropion does not inhibit monoamine oxidase. Bupropion has been found to be essentially inactive at the serotonin transporter (SERT)(IC50 >10 000 nM), however both bupropion and its primary metabolite hydroxybupropion have been found to block the function of cation-selective serotonin type 3A receptors (5-HT3ARs). Bupropion produces dose-related central nervous system (CNS) stimulant effects in animals, as evidenced by increased locomotor activity, increased rates of responding in various schedule-controlled operant behaviour tasks, and, at high doses, induction of mild stereotyped behaviour. Due to these stimulant effects and selective activity at dopamine and norepinephrine receptors, bupropion has been identified as having an abuse potential. Bupropion has a similar structure to the controlled substance Cathinone, and has been identified as having mild amphetamine-like activity, particularly when inhaled or injected. Bupropion is also known to lower the seizure threshold, making any pre-existing seizure conditions a contraindication to its use. This risk is exacerbated when bupropion is combined with other drugs or substances that lower the seizure threshold, such as cocaine, or in clinical situations that would increase the risk of a seizure such as abrupt alcohol or benzodiazepine withdrawal. As norepinephrine has been shown to have anticonvulsant properties, bupropion's inhibitory effects on NET are thought to contribute to its pro-convulsant activity. Bupropion has been shown to increase blood pressure and pose a risk for exacerbation of unmanaged or pre-existing hypertension, however, clinical trials of bupropion in smokers with CVD have not identified an increased incidence of CV events including stroke or heart attack. In clinical trials, the mean increase in systolic blood pressure associated with the use of bupropion was found to be 1.3 mmHg. •Pharmacodynamics (Drug B): Oritavancin interferes with bacterial cell wall synthesis and integrity, treating susceptible skin and subcutaneous tissue infections with gram-positive bacteria. This drug is known to artifically increase INR and aPTT, interfering with coagulation testing. Cases of infusion reactions have also been reported. •Mechanism of action (Drug A): Bupropion is a norepinephrine/dopamine-reuptake inhibitor (NDRI) that exerts its pharmacological effects by weakly inhibiting the enzymes involved in the uptake of the neurotransmitters norepinephrine and dopamine from the synaptic cleft, therefore prolonging their duration of action within the neuronal synapse and the downstream effects of these neurotransmitters. More specifically, bupropion binds to the norepinephrine transporter (NET) and the dopamine transporter (DAT). Bupropion was originally classified as an "atypical" antidepressant because it does not exert the same effects as the classical antidepressants such as Monoamine Oxidase Inhibitors (MAOIs), Tricyclic Antidepressants (TCAs), or Selective Serotonin Reuptake Inhibitors (SSRIs). While it has comparable effectiveness to typical first-line options for the treatment of depression such as SSRIs, bupropion is a unique option for the treatment of MDD as it lacks any clinically relevant serotonergic effects, typical of other mood medications, or any effects on histamine or adrenaline receptors. Lack of activity at these receptors results in a more tolerable side effect profile; bupropion is less likely to cause sexual side effects, sedation, or weight gain as compared to SSRIs or TCAs, for example. When used as an aid to smoking cessation, bupropion is thought to confer its anti-craving and anti-withdrawal effects by inhibiting dopamine reuptake, which is thought to be involved in the reward pathways associated with nicotine, and through the antagonism of the nicotinic acetylcholinergic receptor (AChR), thereby blunting the effects of nicotine. Furthermore, the stimulatory effects produced by bupropion in the central nervous system are similar to nicotine's effects, making low doses of bupropion a suitable option as a nicotine substitute. When used in combination with naltrexone in the marketed product ContraveⓇ for chronic weight management, the two components are thought to have effects on areas of the brain involved in the regulation of food intake. This includes the hypothalamus, which is involved in appetite regulation, and the mesolimbic dopamine circuit, which is involved in reward pathways. Studies have shown that the combined activity of bupropion and naltrexone increase the firing rate of hypothalamic pro-opiomelanocortin (POMC) neurons and blockade of opioid receptor-mediated POMC auto-inhibition, which are associated with a reduction in food intake and increased energy expenditure. This combination was also found to reduce food intake when injected directly into the ventral tegmental area of the mesolimbic circuit in mice, which is an area associated with the regulation of reward pathways. •Mechanism of action (Drug B): The cell wall is vital for the survival and replication of bacteria, making it a primary target for antibiotic therapy. Oritavancin works against susceptible gram-positive organisms via three separate mechanisms. Firstly, it binds to the stem peptide of peptidoglycan precursors, inhibiting transglycosylation (polymerization). This process normally occurs during cell wall synthesis. Secondly, oritavancin inhibits crosslinking during bacterial cell wall biosynthesis via binding to cell wall pentaglycyl peptide bridging segments. Finally, this drug also acts by disrupting the bacterial cell membrane, interfering with its integrity, which eventually leads to cell death by various mechanisms. •Absorption (Drug A): Bupropion is currently available in 3 distinct, but bioequivalent formulations: immediate release (IR), sustained-release (SR), and extended-release (XL). Immediate Release Formulation In humans, following oral administration of bupropion hydrochloride tablets, peak plasma bupropion concentrations are usually achieved within 2 hours. IR formulations provide a short duration of action and are therefore generally dosed three times per day. Sustained Release Formulation In humans, following oral administration of bupropion hydrochloride sustained-release tablets (SR), peak plasma concentration (Cmax) of bupropion is usually achieved within 3 hours. SR formulations provide a 12-hour extended release of medication and are therefore generally dosed twice per day. Extended Release Formulation Following single oral administration of bupropion hydrochloride extended-release tablets (XL) to healthy volunteers, the median time to peak plasma concentrations for bupropion was approximately 5 hours. The presence of food did not affect the peak concentration or area under the curve of bupropion. XL formulations provide a 24-hour extended release of medication and are therefore generally dosed once per day/ In a trial comparing chronic dosing with bupropion hydrochloride extended-release tablets (SR) 150 mg twice daily to bupropion immediate-release formulation 100 mg 3 times daily, the steady state Cmax for bupropion after bupropion hydrochloride sustained-release tablets (SR) administration was approximately 85% of those achieved after bupropion immediate-release formulation administration. Exposure (AUC) to bupropion was equivalent for both formulations. Bioequivalence was also demonstrated for all three major active metabolites (i.e., hydroxybupropion, threohydrobupropion and erythrohydrobupropion) for both Cmax and AUC. Thus, at steady state, bupropion hydrochloride sustained-release tablets (SR) given twice daily, and the immediate-release formulation of bupropion given 3 times daily, are essentially bioequivalent for both bupropion and the 3 quantitatively important metabolites. Furthermore, in a study comparing 14-day dosing with bupropion hydrochloride extended-release tablets (XL), 300 mg once-daily to the immediate-release formulation of bupropion at 100 mg 3 times daily, equivalence was demonstrated for peak plasma concentration and area under the curve for bupropion and the three metabolites (hydroxybupropion, threohydrobupropion, and erythrohydrobupropion). Additionally, in a study comparing 14-day dosing with bupropion hydrochloride extended-release tablets (XL) 300 mg once daily to the sustained-release formulation of bupropion at 150 mg 2 times daily, equivalence was demonstrated for peak plasma concentration and area under the curve for bupropion and the three metabolites. Bupropion hydrochloride extended-release tablets (SR) can be taken with or without food. Bupropion Cmax and AUC were increased by 11% to 35% and 16% to 19%, respectively, when bupropion hydrochloride extended-release tablets (SR) was administered with food to healthy volunteers in three trials. The food effect is not considered clinically significant. Following a single-dose administration of bupropion hydrochloride extended-release tablets (SR) in humans, Cmax of bupropion's metabolite hydroxybupropion occurs approximately 6 hours post-dose and is approximately 10 times the peak level of the parent drug at steady state. The elimination half-life of hydroxybupropion is approximately 20 (±5) hours and its AUC at steady state is about 17 times that of bupropion. The times to peak concentrations for the erythrohydrobupropion and threohydrobupropion metabolites are similar to that of the hydroxybupropion metabolite. However, their elimination half-lives are longer, 33(±10) and 37 (±13) hours, respectively, and steady-state AUCs are 1.5 and 7 times that of bupropion, respectively. •Absorption (Drug B): Pharmacokinetic analysis of oritavancin revealed a Cmax of 138 and μg/mL and an AUC0-∞ of 2800 μg•h/mL. The AUC0-t in a study of healthy volunteers after an 800 mg dose 1,1111 μg•h/mL. was also be Another pharmacokinetic study reported a Cmax of 4.7-7.6 micrograms/mL, generally achieved within 24 hours of administration. •Volume of distribution (Drug A): No volume of distribution available •Volume of distribution (Drug B): The volume of distribution of oritavancin is estimated at 87.6 L, suggesting extensive tissue distribution. •Protein binding (Drug A): In vitro tests show that bupropion is 84% bound to human plasma proteins at concentrations up to 200 mcg per mL. The extent of protein binding of the hydroxybupropion metabolite is similar to that for bupropion, whereas the extent of protein binding of the threohydrobupropion metabolite is about half that seen with bupropion. •Protein binding (Drug B): Oritavancin is about 85% bound to plasma proteins. •Metabolism (Drug A): Bupropion is extensively metabolized in humans. Three metabolites are active: hydroxybupropion, which is formed via hydroxylation of the tert-butyl group of bupropion, and the amino-alcohol isomers, threohydrobupropion and erythrohydrobupropion, which are formed via reduction of the carbonyl group. In vitro findings suggest that CYP2B6 is the principal isoenzyme involved in the formation of hydroxybupropion, while cytochrome P450 enzymes are not involved in the formation of threohydrobupropion. Hydroxybupropion has been shown to have the same affinity as bupropion for the norepinephrine transporter (NET) but approximately 50% of its antidepressant activity despite reaching concentrations of ~10-fold higher than that of the parent drug. Oxidation of the bupropion side chain results in the formation of a glycine conjugate of meta-chlorobenzoic acid, which is then excreted as the major urinary metabolite. The potency and toxicity of the metabolites relative to bupropion have not been fully characterized. However, it has been demonstrated in an antidepressant screening test in mice that hydroxybupropion is one-half as potent as bupropion, while threohydrobupropion and erythrohydrobupropion are 5-fold less potent than bupropion. This may be of clinical importance because the plasma concentrations of the metabolites are as high as or higher than those of bupropion. Bupropion and its metabolites exhibit linear kinetics following chronic administration of 300 to 450 mg per day. •Metabolism (Drug B): In vitro studies on human hepatocytes suggest that oritavancin is not metabolized, and is excreted unchanged. •Route of elimination (Drug A): Bupropion is extensively metabolized in humans. Oxidation of the bupropion side chain results in the formation of a glycine conjugate of metachlorobenzoic acid, which is then excreted as the major urinary metabolite. Following oral administration of 200 mg of 14C-bupropion in humans, 87% and 10% of the radioactive dose were recovered in the urine and feces, respectively. However, the fraction of the oral dose of bupropion excreted unchanged was only 0.5%, a finding consistent with the extensive metabolism of bupropion. •Route of elimination (Drug B): Oritavancin is excreted as unchanged drug in both the urine and feces. Less than 5% has been recovered in the urine, and 1% has been recovered in the feces. •Half-life (Drug A): 24 hours •Half-life (Drug B): The average terminal half-life of oritavancin is about 245 hours. A pharmacokinetic study revealed a terminal half-life ranging from 135.8-273.8 hours. •Clearance (Drug A): No clearance available •Clearance (Drug B): The clearance of oritavancin is approximately 0.445 L/h. One study revealed a renal clearance of 0.457 mL/min. •Toxicity (Drug A): Symptoms of overdose include seizures, hallucinations, loss of consciousness, tachycardia, and cardiac arrest. •Toxicity (Drug B): The LD50 of oritavancin in rats is >500m mg/kg. Prescribing information indicates no experience with overdose during the clinical program for oritavancin, however, an overdose is likely to result in an increased risk of adverse effects, such as headache, nausea vomiting, and diarrhea. This drug is not dialyzable, and in the case of an overdose, supportive measures should be undertaken. •Brand Names (Drug A): Aplenzin, Auvelity, Budeprion, Contrave, Forfivo, Wellbutrin, Zyban •Brand Names (Drug B): Kimyrsa, Orbactiv •Synonyms (Drug A): No synonyms listed •Synonyms (Drug B): Oritavancin •Summary (Drug A): Bupropion is a norepinephrine and dopamine reuptake inhibitor used in the treatment of major depressive disorder (MDD), seasonal affective disorder (SAD), and as an aid to smoking cessation. •Summary (Drug B): Oritavancin is an antibacterial agent used to treat acute bacterial skin and skin structure infections caused by susceptible Gram-positive bacteria.

The subject drug is known to be a weak inhibitor of CYP2C9 while the affected drug is reported to be metabolized by CYP2C9. Concomitant administration of these agents can cause an increase in the serum concentration of the affected drug due to decreased metabolism by CYP2C9, which may result in increased incidence and/or severity of adverse effects related to the affected drug. The severity of the interaction is minor.

Question: Does Bupropion and Oritavancin interact? Information: •Drug A: Bupropion •Drug B: Oritavancin •Severity: MINOR •Description: The metabolism of Bupropion can be decreased when combined with Oritavancin. •Extended Description: The subject drug is known to be a weak inhibitor of CYP2C9 while the affected drug is reported to be metabolized by CYP2C9. Concomitant administration of these agents can cause an increase in the serum concentration of the affected drug due to decreased metabolism by CYP2C9, which may result in increased incidence and/or severity of adverse effects related to the affected drug. •Indication (Drug A): Bupropion is indicated for the treatment of major depressive disorder (MDD), seasonal affective disorder (SAD), and as an aid to smoking cessation. When used in combination with naltrexone as the marketed product ContraveⓇ, bupropion is indicated as an adjunct to a reduced-calorie diet and increased physical activity for chronic weight management in adults with an initial body mass index (BMI) of: 30 kg/m^2 or greater (obese) or 27 kg/m^2 or greater (overweight) in the presence of at least one weight-related comorbid condition (e.g., hypertension, type 2 diabetes mellitus, or dyslipidemia). Bupropion is also used off-label as a first-line treatment in patients with ADHD and comorbid bipolar disorder when used as an adjunct to mood stabilizers. •Indication (Drug B): Oritavancin is indicated for the treatment of adult patients with acute bacterial skin and skin structure (including subcutaneous) infection. It is used for confirmed/suspected infections with designated and susceptible gram-positive organisms. There are two preparations of oritavancin; the 400 mg dose that is administered over 3 hours, and the 1200 mg dose administered over 1 hour. Both are indicated for susceptible gram-positive skin and skin structure infections in adults. As antimicrobial susceptibility patterns are geographically distinct, local antibiograms should be consulted to ensure adequate coverage of relevant pathogens prior to use. •Pharmacodynamics (Drug A): Bupropion is chemically unrelated to tricyclic, tetracyclic, selective serotonin re-uptake inhibitors, or other known antidepressant agents. Compared to classical tricyclic antidepressants, Bupropion is a relatively weak inhibitor of the neuronal uptake of norepinephrine and dopamine. In addition, Bupropion does not inhibit monoamine oxidase. Bupropion has been found to be essentially inactive at the serotonin transporter (SERT)(IC50 >10 000 nM), however both bupropion and its primary metabolite hydroxybupropion have been found to block the function of cation-selective serotonin type 3A receptors (5-HT3ARs). Bupropion produces dose-related central nervous system (CNS) stimulant effects in animals, as evidenced by increased locomotor activity, increased rates of responding in various schedule-controlled operant behaviour tasks, and, at high doses, induction of mild stereotyped behaviour. Due to these stimulant effects and selective activity at dopamine and norepinephrine receptors, bupropion has been identified as having an abuse potential. Bupropion has a similar structure to the controlled substance Cathinone, and has been identified as having mild amphetamine-like activity, particularly when inhaled or injected. Bupropion is also known to lower the seizure threshold, making any pre-existing seizure conditions a contraindication to its use. This risk is exacerbated when bupropion is combined with other drugs or substances that lower the seizure threshold, such as cocaine, or in clinical situations that would increase the risk of a seizure such as abrupt alcohol or benzodiazepine withdrawal. As norepinephrine has been shown to have anticonvulsant properties, bupropion's inhibitory effects on NET are thought to contribute to its pro-convulsant activity. Bupropion has been shown to increase blood pressure and pose a risk for exacerbation of unmanaged or pre-existing hypertension, however, clinical trials of bupropion in smokers with CVD have not identified an increased incidence of CV events including stroke or heart attack. In clinical trials, the mean increase in systolic blood pressure associated with the use of bupropion was found to be 1.3 mmHg. •Pharmacodynamics (Drug B): Oritavancin interferes with bacterial cell wall synthesis and integrity, treating susceptible skin and subcutaneous tissue infections with gram-positive bacteria. This drug is known to artifically increase INR and aPTT, interfering with coagulation testing. Cases of infusion reactions have also been reported. •Mechanism of action (Drug A): Bupropion is a norepinephrine/dopamine-reuptake inhibitor (NDRI) that exerts its pharmacological effects by weakly inhibiting the enzymes involved in the uptake of the neurotransmitters norepinephrine and dopamine from the synaptic cleft, therefore prolonging their duration of action within the neuronal synapse and the downstream effects of these neurotransmitters. More specifically, bupropion binds to the norepinephrine transporter (NET) and the dopamine transporter (DAT). Bupropion was originally classified as an "atypical" antidepressant because it does not exert the same effects as the classical antidepressants such as Monoamine Oxidase Inhibitors (MAOIs), Tricyclic Antidepressants (TCAs), or Selective Serotonin Reuptake Inhibitors (SSRIs). While it has comparable effectiveness to typical first-line options for the treatment of depression such as SSRIs, bupropion is a unique option for the treatment of MDD as it lacks any clinically relevant serotonergic effects, typical of other mood medications, or any effects on histamine or adrenaline receptors. Lack of activity at these receptors results in a more tolerable side effect profile; bupropion is less likely to cause sexual side effects, sedation, or weight gain as compared to SSRIs or TCAs, for example. When used as an aid to smoking cessation, bupropion is thought to confer its anti-craving and anti-withdrawal effects by inhibiting dopamine reuptake, which is thought to be involved in the reward pathways associated with nicotine, and through the antagonism of the nicotinic acetylcholinergic receptor (AChR), thereby blunting the effects of nicotine. Furthermore, the stimulatory effects produced by bupropion in the central nervous system are similar to nicotine's effects, making low doses of bupropion a suitable option as a nicotine substitute. When used in combination with naltrexone in the marketed product ContraveⓇ for chronic weight management, the two components are thought to have effects on areas of the brain involved in the regulation of food intake. This includes the hypothalamus, which is involved in appetite regulation, and the mesolimbic dopamine circuit, which is involved in reward pathways. Studies have shown that the combined activity of bupropion and naltrexone increase the firing rate of hypothalamic pro-opiomelanocortin (POMC) neurons and blockade of opioid receptor-mediated POMC auto-inhibition, which are associated with a reduction in food intake and increased energy expenditure. This combination was also found to reduce food intake when injected directly into the ventral tegmental area of the mesolimbic circuit in mice, which is an area associated with the regulation of reward pathways. •Mechanism of action (Drug B): The cell wall is vital for the survival and replication of bacteria, making it a primary target for antibiotic therapy. Oritavancin works against susceptible gram-positive organisms via three separate mechanisms. Firstly, it binds to the stem peptide of peptidoglycan precursors, inhibiting transglycosylation (polymerization). This process normally occurs during cell wall synthesis. Secondly, oritavancin inhibits crosslinking during bacterial cell wall biosynthesis via binding to cell wall pentaglycyl peptide bridging segments. Finally, this drug also acts by disrupting the bacterial cell membrane, interfering with its integrity, which eventually leads to cell death by various mechanisms. •Absorption (Drug A): Bupropion is currently available in 3 distinct, but bioequivalent formulations: immediate release (IR), sustained-release (SR), and extended-release (XL). Immediate Release Formulation In humans, following oral administration of bupropion hydrochloride tablets, peak plasma bupropion concentrations are usually achieved within 2 hours. IR formulations provide a short duration of action and are therefore generally dosed three times per day. Sustained Release Formulation In humans, following oral administration of bupropion hydrochloride sustained-release tablets (SR), peak plasma concentration (Cmax) of bupropion is usually achieved within 3 hours. SR formulations provide a 12-hour extended release of medication and are therefore generally dosed twice per day. Extended Release Formulation Following single oral administration of bupropion hydrochloride extended-release tablets (XL) to healthy volunteers, the median time to peak plasma concentrations for bupropion was approximately 5 hours. The presence of food did not affect the peak concentration or area under the curve of bupropion. XL formulations provide a 24-hour extended release of medication and are therefore generally dosed once per day/ In a trial comparing chronic dosing with bupropion hydrochloride extended-release tablets (SR) 150 mg twice daily to bupropion immediate-release formulation 100 mg 3 times daily, the steady state Cmax for bupropion after bupropion hydrochloride sustained-release tablets (SR) administration was approximately 85% of those achieved after bupropion immediate-release formulation administration. Exposure (AUC) to bupropion was equivalent for both formulations. Bioequivalence was also demonstrated for all three major active metabolites (i.e., hydroxybupropion, threohydrobupropion and erythrohydrobupropion) for both Cmax and AUC. Thus, at steady state, bupropion hydrochloride sustained-release tablets (SR) given twice daily, and the immediate-release formulation of bupropion given 3 times daily, are essentially bioequivalent for both bupropion and the 3 quantitatively important metabolites. Furthermore, in a study comparing 14-day dosing with bupropion hydrochloride extended-release tablets (XL), 300 mg once-daily to the immediate-release formulation of bupropion at 100 mg 3 times daily, equivalence was demonstrated for peak plasma concentration and area under the curve for bupropion and the three metabolites (hydroxybupropion, threohydrobupropion, and erythrohydrobupropion). Additionally, in a study comparing 14-day dosing with bupropion hydrochloride extended-release tablets (XL) 300 mg once daily to the sustained-release formulation of bupropion at 150 mg 2 times daily, equivalence was demonstrated for peak plasma concentration and area under the curve for bupropion and the three metabolites. Bupropion hydrochloride extended-release tablets (SR) can be taken with or without food. Bupropion Cmax and AUC were increased by 11% to 35% and 16% to 19%, respectively, when bupropion hydrochloride extended-release tablets (SR) was administered with food to healthy volunteers in three trials. The food effect is not considered clinically significant. Following a single-dose administration of bupropion hydrochloride extended-release tablets (SR) in humans, Cmax of bupropion's metabolite hydroxybupropion occurs approximately 6 hours post-dose and is approximately 10 times the peak level of the parent drug at steady state. The elimination half-life of hydroxybupropion is approximately 20 (±5) hours and its AUC at steady state is about 17 times that of bupropion. The times to peak concentrations for the erythrohydrobupropion and threohydrobupropion metabolites are similar to that of the hydroxybupropion metabolite. However, their elimination half-lives are longer, 33(±10) and 37 (±13) hours, respectively, and steady-state AUCs are 1.5 and 7 times that of bupropion, respectively. •Absorption (Drug B): Pharmacokinetic analysis of oritavancin revealed a Cmax of 138 and μg/mL and an AUC0-∞ of 2800 μg•h/mL. The AUC0-t in a study of healthy volunteers after an 800 mg dose 1,1111 μg•h/mL. was also be Another pharmacokinetic study reported a Cmax of 4.7-7.6 micrograms/mL, generally achieved within 24 hours of administration. •Volume of distribution (Drug A): No volume of distribution available •Volume of distribution (Drug B): The volume of distribution of oritavancin is estimated at 87.6 L, suggesting extensive tissue distribution. •Protein binding (Drug A): In vitro tests show that bupropion is 84% bound to human plasma proteins at concentrations up to 200 mcg per mL. The extent of protein binding of the hydroxybupropion metabolite is similar to that for bupropion, whereas the extent of protein binding of the threohydrobupropion metabolite is about half that seen with bupropion. •Protein binding (Drug B): Oritavancin is about 85% bound to plasma proteins. •Metabolism (Drug A): Bupropion is extensively metabolized in humans. Three metabolites are active: hydroxybupropion, which is formed via hydroxylation of the tert-butyl group of bupropion, and the amino-alcohol isomers, threohydrobupropion and erythrohydrobupropion, which are formed via reduction of the carbonyl group. In vitro findings suggest that CYP2B6 is the principal isoenzyme involved in the formation of hydroxybupropion, while cytochrome P450 enzymes are not involved in the formation of threohydrobupropion. Hydroxybupropion has been shown to have the same affinity as bupropion for the norepinephrine transporter (NET) but approximately 50% of its antidepressant activity despite reaching concentrations of ~10-fold higher than that of the parent drug. Oxidation of the bupropion side chain results in the formation of a glycine conjugate of meta-chlorobenzoic acid, which is then excreted as the major urinary metabolite. The potency and toxicity of the metabolites relative to bupropion have not been fully characterized. However, it has been demonstrated in an antidepressant screening test in mice that hydroxybupropion is one-half as potent as bupropion, while threohydrobupropion and erythrohydrobupropion are 5-fold less potent than bupropion. This may be of clinical importance because the plasma concentrations of the metabolites are as high as or higher than those of bupropion. Bupropion and its metabolites exhibit linear kinetics following chronic administration of 300 to 450 mg per day. •Metabolism (Drug B): In vitro studies on human hepatocytes suggest that oritavancin is not metabolized, and is excreted unchanged. •Route of elimination (Drug A): Bupropion is extensively metabolized in humans. Oxidation of the bupropion side chain results in the formation of a glycine conjugate of metachlorobenzoic acid, which is then excreted as the major urinary metabolite. Following oral administration of 200 mg of 14C-bupropion in humans, 87% and 10% of the radioactive dose were recovered in the urine and feces, respectively. However, the fraction of the oral dose of bupropion excreted unchanged was only 0.5%, a finding consistent with the extensive metabolism of bupropion. •Route of elimination (Drug B): Oritavancin is excreted as unchanged drug in both the urine and feces. Less than 5% has been recovered in the urine, and 1% has been recovered in the feces. •Half-life (Drug A): 24 hours •Half-life (Drug B): The average terminal half-life of oritavancin is about 245 hours. A pharmacokinetic study revealed a terminal half-life ranging from 135.8-273.8 hours. •Clearance (Drug A): No clearance available •Clearance (Drug B): The clearance of oritavancin is approximately 0.445 L/h. One study revealed a renal clearance of 0.457 mL/min. •Toxicity (Drug A): Symptoms of overdose include seizures, hallucinations, loss of consciousness, tachycardia, and cardiac arrest. •Toxicity (Drug B): The LD50 of oritavancin in rats is >500m mg/kg. Prescribing information indicates no experience with overdose during the clinical program for oritavancin, however, an overdose is likely to result in an increased risk of adverse effects, such as headache, nausea vomiting, and diarrhea. This drug is not dialyzable, and in the case of an overdose, supportive measures should be undertaken. •Brand Names (Drug A): Aplenzin, Auvelity, Budeprion, Contrave, Forfivo, Wellbutrin, Zyban •Brand Names (Drug B): Kimyrsa, Orbactiv •Synonyms (Drug A): No synonyms listed •Synonyms (Drug B): Oritavancin •Summary (Drug A): Bupropion is a norepinephrine and dopamine reuptake inhibitor used in the treatment of major depressive disorder (MDD), seasonal affective disorder (SAD), and as an aid to smoking cessation. •Summary (Drug B): Oritavancin is an antibacterial agent used to treat acute bacterial skin and skin structure infections caused by susceptible Gram-positive bacteria. Output: The subject drug is known to be a weak inhibitor of CYP2C9 while the affected drug is reported to be metabolized by CYP2C9. Concomitant administration of these agents can cause an increase in the serum concentration of the affected drug due to decreased metabolism by CYP2C9, which may result in increased incidence and/or severity of adverse effects related to the affected drug. The severity of the interaction is minor.

Does Bupropion and Orphenadrine interact?

•Drug A: Bupropion •Drug B: Orphenadrine •Severity: MODERATE •Description: The risk or severity of adverse effects can be increased when Bupropion is combined with Orphenadrine. •Extended Description: Despite the fact that these drugs are sometimes used in combination to treat depression in Parkinson's disease3, the administration of bupropion with anti-Parkinson drugs may lead to central nervous system toxicity. Bupropion is considered a norepinephrine-dopamine reuptake inhibitor, is found to occupy the DAT dopamine transporter, and acts as a dopamine agonist. Additive effects of these dopaminergic drugs may produce excess dopaminergic activity. Agitation, restlessness, tremor, ataxia, gait disturbance, and dizziness are some examples of effects that may occur from concurrent administration. •Indication (Drug A): Bupropion is indicated for the treatment of major depressive disorder (MDD), seasonal affective disorder (SAD), and as an aid to smoking cessation. When used in combination with naltrexone as the marketed product ContraveⓇ, bupropion is indicated as an adjunct to a reduced-calorie diet and increased physical activity for chronic weight management in adults with an initial body mass index (BMI) of: 30 kg/m^2 or greater (obese) or 27 kg/m^2 or greater (overweight) in the presence of at least one weight-related comorbid condition (e.g., hypertension, type 2 diabetes mellitus, or dyslipidemia). Bupropion is also used off-label as a first-line treatment in patients with ADHD and comorbid bipolar disorder when used as an adjunct to mood stabilizers. •Indication (Drug B): Indicated as an adjunct to rest, physical therapy, and other measures for the relief of discomfort associated with acute painful musculo skeletal conditions. •Pharmacodynamics (Drug A): Bupropion is chemically unrelated to tricyclic, tetracyclic, selective serotonin re-uptake inhibitors, or other known antidepressant agents. Compared to classical tricyclic antidepressants, Bupropion is a relatively weak inhibitor of the neuronal uptake of norepinephrine and dopamine. In addition, Bupropion does not inhibit monoamine oxidase. Bupropion has been found to be essentially inactive at the serotonin transporter (SERT)(IC50 >10 000 nM), however both bupropion and its primary metabolite hydroxybupropion have been found to block the function of cation-selective serotonin type 3A receptors (5-HT3ARs). Bupropion produces dose-related central nervous system (CNS) stimulant effects in animals, as evidenced by increased locomotor activity, increased rates of responding in various schedule-controlled operant behaviour tasks, and, at high doses, induction of mild stereotyped behaviour. Due to these stimulant effects and selective activity at dopamine and norepinephrine receptors, bupropion has been identified as having an abuse potential. Bupropion has a similar structure to the controlled substance Cathinone, and has been identified as having mild amphetamine-like activity, particularly when inhaled or injected. Bupropion is also known to lower the seizure threshold, making any pre-existing seizure conditions a contraindication to its use. This risk is exacerbated when bupropion is combined with other drugs or substances that lower the seizure threshold, such as cocaine, or in clinical situations that would increase the risk of a seizure such as abrupt alcohol or benzodiazepine withdrawal. As norepinephrine has been shown to have anticonvulsant properties, bupropion's inhibitory effects on NET are thought to contribute to its pro-convulsant activity. Bupropion has been shown to increase blood pressure and pose a risk for exacerbation of unmanaged or pre-existing hypertension, however, clinical trials of bupropion in smokers with CVD have not identified an increased incidence of CV events including stroke or heart attack. In clinical trials, the mean increase in systolic blood pressure associated with the use of bupropion was found to be 1.3 mmHg. •Pharmacodynamics (Drug B): Orphenadrine is indicated as an adjunct to rest, physical therapy, and other measures for the relief of discomfort associated with acute painful musculoskeletal conditions. Orphenadrine is an anticholinergic with a predominantly central effect and only a weak peripheral effect. In addition, it has mild antihistaminic and local anaesthetic properties. Parkinson's syndrome is the consequence of a disturbed balance between cholinergic and dopaminergic neurotransmission in the basal ganglia caused by a decrease in dopamine. Orphenadrine restores the physiological equilibrium and has a favourable effect on the rigidity and tremor of Parkinson's disease and Parkinsonian syndromes. The effect is somewhat less on bradykinesia. •Mechanism of action (Drug A): Bupropion is a norepinephrine/dopamine-reuptake inhibitor (NDRI) that exerts its pharmacological effects by weakly inhibiting the enzymes involved in the uptake of the neurotransmitters norepinephrine and dopamine from the synaptic cleft, therefore prolonging their duration of action within the neuronal synapse and the downstream effects of these neurotransmitters. More specifically, bupropion binds to the norepinephrine transporter (NET) and the dopamine transporter (DAT). Bupropion was originally classified as an "atypical" antidepressant because it does not exert the same effects as the classical antidepressants such as Monoamine Oxidase Inhibitors (MAOIs), Tricyclic Antidepressants (TCAs), or Selective Serotonin Reuptake Inhibitors (SSRIs). While it has comparable effectiveness to typical first-line options for the treatment of depression such as SSRIs, bupropion is a unique option for the treatment of MDD as it lacks any clinically relevant serotonergic effects, typical of other mood medications, or any effects on histamine or adrenaline receptors. Lack of activity at these receptors results in a more tolerable side effect profile; bupropion is less likely to cause sexual side effects, sedation, or weight gain as compared to SSRIs or TCAs, for example. When used as an aid to smoking cessation, bupropion is thought to confer its anti-craving and anti-withdrawal effects by inhibiting dopamine reuptake, which is thought to be involved in the reward pathways associated with nicotine, and through the antagonism of the nicotinic acetylcholinergic receptor (AChR), thereby blunting the effects of nicotine. Furthermore, the stimulatory effects produced by bupropion in the central nervous system are similar to nicotine's effects, making low doses of bupropion a suitable option as a nicotine substitute. When used in combination with naltrexone in the marketed product ContraveⓇ for chronic weight management, the two components are thought to have effects on areas of the brain involved in the regulation of food intake. This includes the hypothalamus, which is involved in appetite regulation, and the mesolimbic dopamine circuit, which is involved in reward pathways. Studies have shown that the combined activity of bupropion and naltrexone increase the firing rate of hypothalamic pro-opiomelanocortin (POMC) neurons and blockade of opioid receptor-mediated POMC auto-inhibition, which are associated with a reduction in food intake and increased energy expenditure. This combination was also found to reduce food intake when injected directly into the ventral tegmental area of the mesolimbic circuit in mice, which is an area associated with the regulation of reward pathways. •Mechanism of action (Drug B): Orphenadrine binds and inhibits both histamine H1 receptors and NMDA receptors. It restores the motor disturbances induced by neuroleptics, in particular the hyperkinesia. The dopamine deficiency in the striatum increases the stimulating effects of the cholinergic system. This stimulation is counteracted by the anticholinergic effect of orphenadrine. It may have a relaxing effect on skeletal muscle spasms and it has a mood elevating effect. •Absorption (Drug A): Bupropion is currently available in 3 distinct, but bioequivalent formulations: immediate release (IR), sustained-release (SR), and extended-release (XL). Immediate Release Formulation In humans, following oral administration of bupropion hydrochloride tablets, peak plasma bupropion concentrations are usually achieved within 2 hours. IR formulations provide a short duration of action and are therefore generally dosed three times per day. Sustained Release Formulation In humans, following oral administration of bupropion hydrochloride sustained-release tablets (SR), peak plasma concentration (Cmax) of bupropion is usually achieved within 3 hours. SR formulations provide a 12-hour extended release of medication and are therefore generally dosed twice per day. Extended Release Formulation Following single oral administration of bupropion hydrochloride extended-release tablets (XL) to healthy volunteers, the median time to peak plasma concentrations for bupropion was approximately 5 hours. The presence of food did not affect the peak concentration or area under the curve of bupropion. XL formulations provide a 24-hour extended release of medication and are therefore generally dosed once per day/ In a trial comparing chronic dosing with bupropion hydrochloride extended-release tablets (SR) 150 mg twice daily to bupropion immediate-release formulation 100 mg 3 times daily, the steady state Cmax for bupropion after bupropion hydrochloride sustained-release tablets (SR) administration was approximately 85% of those achieved after bupropion immediate-release formulation administration. Exposure (AUC) to bupropion was equivalent for both formulations. Bioequivalence was also demonstrated for all three major active metabolites (i.e., hydroxybupropion, threohydrobupropion and erythrohydrobupropion) for both Cmax and AUC. Thus, at steady state, bupropion hydrochloride sustained-release tablets (SR) given twice daily, and the immediate-release formulation of bupropion given 3 times daily, are essentially bioequivalent for both bupropion and the 3 quantitatively important metabolites. Furthermore, in a study comparing 14-day dosing with bupropion hydrochloride extended-release tablets (XL), 300 mg once-daily to the immediate-release formulation of bupropion at 100 mg 3 times daily, equivalence was demonstrated for peak plasma concentration and area under the curve for bupropion and the three metabolites (hydroxybupropion, threohydrobupropion, and erythrohydrobupropion). Additionally, in a study comparing 14-day dosing with bupropion hydrochloride extended-release tablets (XL) 300 mg once daily to the sustained-release formulation of bupropion at 150 mg 2 times daily, equivalence was demonstrated for peak plasma concentration and area under the curve for bupropion and the three metabolites. Bupropion hydrochloride extended-release tablets (SR) can be taken with or without food. Bupropion Cmax and AUC were increased by 11% to 35% and 16% to 19%, respectively, when bupropion hydrochloride extended-release tablets (SR) was administered with food to healthy volunteers in three trials. The food effect is not considered clinically significant. Following a single-dose administration of bupropion hydrochloride extended-release tablets (SR) in humans, Cmax of bupropion's metabolite hydroxybupropion occurs approximately 6 hours post-dose and is approximately 10 times the peak level of the parent drug at steady state. The elimination half-life of hydroxybupropion is approximately 20 (±5) hours and its AUC at steady state is about 17 times that of bupropion. The times to peak concentrations for the erythrohydrobupropion and threohydrobupropion metabolites are similar to that of the hydroxybupropion metabolite. However, their elimination half-lives are longer, 33(±10) and 37 (±13) hours, respectively, and steady-state AUCs are 1.5 and 7 times that of bupropion, respectively. •Absorption (Drug B): Orphenadrine is almost completely absorbed in the gastrointestinal tract. •Volume of distribution (Drug A): No volume of distribution available •Volume of distribution (Drug B): No volume of distribution available •Protein binding (Drug A): In vitro tests show that bupropion is 84% bound to human plasma proteins at concentrations up to 200 mcg per mL. The extent of protein binding of the hydroxybupropion metabolite is similar to that for bupropion, whereas the extent of protein binding of the threohydrobupropion metabolite is about half that seen with bupropion. •Protein binding (Drug B): 95% •Metabolism (Drug A): Bupropion is extensively metabolized in humans. Three metabolites are active: hydroxybupropion, which is formed via hydroxylation of the tert-butyl group of bupropion, and the amino-alcohol isomers, threohydrobupropion and erythrohydrobupropion, which are formed via reduction of the carbonyl group. In vitro findings suggest that CYP2B6 is the principal isoenzyme involved in the formation of hydroxybupropion, while cytochrome P450 enzymes are not involved in the formation of threohydrobupropion. Hydroxybupropion has been shown to have the same affinity as bupropion for the norepinephrine transporter (NET) but approximately 50% of its antidepressant activity despite reaching concentrations of ~10-fold higher than that of the parent drug. Oxidation of the bupropion side chain results in the formation of a glycine conjugate of meta-chlorobenzoic acid, which is then excreted as the major urinary metabolite. The potency and toxicity of the metabolites relative to bupropion have not been fully characterized. However, it has been demonstrated in an antidepressant screening test in mice that hydroxybupropion is one-half as potent as bupropion, while threohydrobupropion and erythrohydrobupropion are 5-fold less potent than bupropion. This may be of clinical importance because the plasma concentrations of the metabolites are as high as or higher than those of bupropion. Bupropion and its metabolites exhibit linear kinetics following chronic administration of 300 to 450 mg per day. •Metabolism (Drug B): Biotransformation occurs mainly in the liver. Pharmacologically active metabolites are N-demethyl orphenadrine and N,N-didemethyl orphenadrine. •Route of elimination (Drug A): Bupropion is extensively metabolized in humans. Oxidation of the bupropion side chain results in the formation of a glycine conjugate of metachlorobenzoic acid, which is then excreted as the major urinary metabolite. Following oral administration of 200 mg of 14C-bupropion in humans, 87% and 10% of the radioactive dose were recovered in the urine and feces, respectively. However, the fraction of the oral dose of bupropion excreted unchanged was only 0.5%, a finding consistent with the extensive metabolism of bupropion. •Route of elimination (Drug B): No route of elimination available •Half-life (Drug A): 24 hours •Half-life (Drug B): 13-20 hours •Clearance (Drug A): No clearance available •Clearance (Drug B): No clearance available •Toxicity (Drug A): Symptoms of overdose include seizures, hallucinations, loss of consciousness, tachycardia, and cardiac arrest. •Toxicity (Drug B): Oral, mouse LD 50 = 100 mg/kg; oral, rat LD 50 = 255 mg/kg •Brand Names (Drug A): Aplenzin, Auvelity, Budeprion, Contrave, Forfivo, Wellbutrin, Zyban •Brand Names (Drug B): Norgesic, Norgesic Forte, Orfenace, Orphengesic •Synonyms (Drug A): No synonyms listed •Synonyms (Drug B): Orfenadrina Orphenadrine Orphenadrinum •Summary (Drug A): Bupropion is a norepinephrine and dopamine reuptake inhibitor used in the treatment of major depressive disorder (MDD), seasonal affective disorder (SAD), and as an aid to smoking cessation. •Summary (Drug B): Orphenadrine is a muscarinic antagonist used as an adjunct for the symptomatic relief of musculoskeletal pain and discomfort.

Despite the fact that these drugs are sometimes used in combination to treat depression in Parkinson's disease3, the administration of bupropion with anti-Parkinson drugs may lead to central nervous system toxicity. Bupropion is considered a norepinephrine-dopamine reuptake inhibitor, is found to occupy the DAT dopamine transporter, and acts as a dopamine agonist. Additive effects of these dopaminergic drugs may produce excess dopaminergic activity. Agitation, restlessness, tremor, ataxia, gait disturbance, and dizziness are some examples of effects that may occur from concurrent administration. The severity of the interaction is moderate.

Question: Does Bupropion and Orphenadrine interact? Information: •Drug A: Bupropion •Drug B: Orphenadrine •Severity: MODERATE •Description: The risk or severity of adverse effects can be increased when Bupropion is combined with Orphenadrine. •Extended Description: Despite the fact that these drugs are sometimes used in combination to treat depression in Parkinson's disease3, the administration of bupropion with anti-Parkinson drugs may lead to central nervous system toxicity. Bupropion is considered a norepinephrine-dopamine reuptake inhibitor, is found to occupy the DAT dopamine transporter, and acts as a dopamine agonist. Additive effects of these dopaminergic drugs may produce excess dopaminergic activity. Agitation, restlessness, tremor, ataxia, gait disturbance, and dizziness are some examples of effects that may occur from concurrent administration. •Indication (Drug A): Bupropion is indicated for the treatment of major depressive disorder (MDD), seasonal affective disorder (SAD), and as an aid to smoking cessation. When used in combination with naltrexone as the marketed product ContraveⓇ, bupropion is indicated as an adjunct to a reduced-calorie diet and increased physical activity for chronic weight management in adults with an initial body mass index (BMI) of: 30 kg/m^2 or greater (obese) or 27 kg/m^2 or greater (overweight) in the presence of at least one weight-related comorbid condition (e.g., hypertension, type 2 diabetes mellitus, or dyslipidemia). Bupropion is also used off-label as a first-line treatment in patients with ADHD and comorbid bipolar disorder when used as an adjunct to mood stabilizers. •Indication (Drug B): Indicated as an adjunct to rest, physical therapy, and other measures for the relief of discomfort associated with acute painful musculo skeletal conditions. •Pharmacodynamics (Drug A): Bupropion is chemically unrelated to tricyclic, tetracyclic, selective serotonin re-uptake inhibitors, or other known antidepressant agents. Compared to classical tricyclic antidepressants, Bupropion is a relatively weak inhibitor of the neuronal uptake of norepinephrine and dopamine. In addition, Bupropion does not inhibit monoamine oxidase. Bupropion has been found to be essentially inactive at the serotonin transporter (SERT)(IC50 >10 000 nM), however both bupropion and its primary metabolite hydroxybupropion have been found to block the function of cation-selective serotonin type 3A receptors (5-HT3ARs). Bupropion produces dose-related central nervous system (CNS) stimulant effects in animals, as evidenced by increased locomotor activity, increased rates of responding in various schedule-controlled operant behaviour tasks, and, at high doses, induction of mild stereotyped behaviour. Due to these stimulant effects and selective activity at dopamine and norepinephrine receptors, bupropion has been identified as having an abuse potential. Bupropion has a similar structure to the controlled substance Cathinone, and has been identified as having mild amphetamine-like activity, particularly when inhaled or injected. Bupropion is also known to lower the seizure threshold, making any pre-existing seizure conditions a contraindication to its use. This risk is exacerbated when bupropion is combined with other drugs or substances that lower the seizure threshold, such as cocaine, or in clinical situations that would increase the risk of a seizure such as abrupt alcohol or benzodiazepine withdrawal. As norepinephrine has been shown to have anticonvulsant properties, bupropion's inhibitory effects on NET are thought to contribute to its pro-convulsant activity. Bupropion has been shown to increase blood pressure and pose a risk for exacerbation of unmanaged or pre-existing hypertension, however, clinical trials of bupropion in smokers with CVD have not identified an increased incidence of CV events including stroke or heart attack. In clinical trials, the mean increase in systolic blood pressure associated with the use of bupropion was found to be 1.3 mmHg. •Pharmacodynamics (Drug B): Orphenadrine is indicated as an adjunct to rest, physical therapy, and other measures for the relief of discomfort associated with acute painful musculoskeletal conditions. Orphenadrine is an anticholinergic with a predominantly central effect and only a weak peripheral effect. In addition, it has mild antihistaminic and local anaesthetic properties. Parkinson's syndrome is the consequence of a disturbed balance between cholinergic and dopaminergic neurotransmission in the basal ganglia caused by a decrease in dopamine. Orphenadrine restores the physiological equilibrium and has a favourable effect on the rigidity and tremor of Parkinson's disease and Parkinsonian syndromes. The effect is somewhat less on bradykinesia. •Mechanism of action (Drug A): Bupropion is a norepinephrine/dopamine-reuptake inhibitor (NDRI) that exerts its pharmacological effects by weakly inhibiting the enzymes involved in the uptake of the neurotransmitters norepinephrine and dopamine from the synaptic cleft, therefore prolonging their duration of action within the neuronal synapse and the downstream effects of these neurotransmitters. More specifically, bupropion binds to the norepinephrine transporter (NET) and the dopamine transporter (DAT). Bupropion was originally classified as an "atypical" antidepressant because it does not exert the same effects as the classical antidepressants such as Monoamine Oxidase Inhibitors (MAOIs), Tricyclic Antidepressants (TCAs), or Selective Serotonin Reuptake Inhibitors (SSRIs). While it has comparable effectiveness to typical first-line options for the treatment of depression such as SSRIs, bupropion is a unique option for the treatment of MDD as it lacks any clinically relevant serotonergic effects, typical of other mood medications, or any effects on histamine or adrenaline receptors. Lack of activity at these receptors results in a more tolerable side effect profile; bupropion is less likely to cause sexual side effects, sedation, or weight gain as compared to SSRIs or TCAs, for example. When used as an aid to smoking cessation, bupropion is thought to confer its anti-craving and anti-withdrawal effects by inhibiting dopamine reuptake, which is thought to be involved in the reward pathways associated with nicotine, and through the antagonism of the nicotinic acetylcholinergic receptor (AChR), thereby blunting the effects of nicotine. Furthermore, the stimulatory effects produced by bupropion in the central nervous system are similar to nicotine's effects, making low doses of bupropion a suitable option as a nicotine substitute. When used in combination with naltrexone in the marketed product ContraveⓇ for chronic weight management, the two components are thought to have effects on areas of the brain involved in the regulation of food intake. This includes the hypothalamus, which is involved in appetite regulation, and the mesolimbic dopamine circuit, which is involved in reward pathways. Studies have shown that the combined activity of bupropion and naltrexone increase the firing rate of hypothalamic pro-opiomelanocortin (POMC) neurons and blockade of opioid receptor-mediated POMC auto-inhibition, which are associated with a reduction in food intake and increased energy expenditure. This combination was also found to reduce food intake when injected directly into the ventral tegmental area of the mesolimbic circuit in mice, which is an area associated with the regulation of reward pathways. •Mechanism of action (Drug B): Orphenadrine binds and inhibits both histamine H1 receptors and NMDA receptors. It restores the motor disturbances induced by neuroleptics, in particular the hyperkinesia. The dopamine deficiency in the striatum increases the stimulating effects of the cholinergic system. This stimulation is counteracted by the anticholinergic effect of orphenadrine. It may have a relaxing effect on skeletal muscle spasms and it has a mood elevating effect. •Absorption (Drug A): Bupropion is currently available in 3 distinct, but bioequivalent formulations: immediate release (IR), sustained-release (SR), and extended-release (XL). Immediate Release Formulation In humans, following oral administration of bupropion hydrochloride tablets, peak plasma bupropion concentrations are usually achieved within 2 hours. IR formulations provide a short duration of action and are therefore generally dosed three times per day. Sustained Release Formulation In humans, following oral administration of bupropion hydrochloride sustained-release tablets (SR), peak plasma concentration (Cmax) of bupropion is usually achieved within 3 hours. SR formulations provide a 12-hour extended release of medication and are therefore generally dosed twice per day. Extended Release Formulation Following single oral administration of bupropion hydrochloride extended-release tablets (XL) to healthy volunteers, the median time to peak plasma concentrations for bupropion was approximately 5 hours. The presence of food did not affect the peak concentration or area under the curve of bupropion. XL formulations provide a 24-hour extended release of medication and are therefore generally dosed once per day/ In a trial comparing chronic dosing with bupropion hydrochloride extended-release tablets (SR) 150 mg twice daily to bupropion immediate-release formulation 100 mg 3 times daily, the steady state Cmax for bupropion after bupropion hydrochloride sustained-release tablets (SR) administration was approximately 85% of those achieved after bupropion immediate-release formulation administration. Exposure (AUC) to bupropion was equivalent for both formulations. Bioequivalence was also demonstrated for all three major active metabolites (i.e., hydroxybupropion, threohydrobupropion and erythrohydrobupropion) for both Cmax and AUC. Thus, at steady state, bupropion hydrochloride sustained-release tablets (SR) given twice daily, and the immediate-release formulation of bupropion given 3 times daily, are essentially bioequivalent for both bupropion and the 3 quantitatively important metabolites. Furthermore, in a study comparing 14-day dosing with bupropion hydrochloride extended-release tablets (XL), 300 mg once-daily to the immediate-release formulation of bupropion at 100 mg 3 times daily, equivalence was demonstrated for peak plasma concentration and area under the curve for bupropion and the three metabolites (hydroxybupropion, threohydrobupropion, and erythrohydrobupropion). Additionally, in a study comparing 14-day dosing with bupropion hydrochloride extended-release tablets (XL) 300 mg once daily to the sustained-release formulation of bupropion at 150 mg 2 times daily, equivalence was demonstrated for peak plasma concentration and area under the curve for bupropion and the three metabolites. Bupropion hydrochloride extended-release tablets (SR) can be taken with or without food. Bupropion Cmax and AUC were increased by 11% to 35% and 16% to 19%, respectively, when bupropion hydrochloride extended-release tablets (SR) was administered with food to healthy volunteers in three trials. The food effect is not considered clinically significant. Following a single-dose administration of bupropion hydrochloride extended-release tablets (SR) in humans, Cmax of bupropion's metabolite hydroxybupropion occurs approximately 6 hours post-dose and is approximately 10 times the peak level of the parent drug at steady state. The elimination half-life of hydroxybupropion is approximately 20 (±5) hours and its AUC at steady state is about 17 times that of bupropion. The times to peak concentrations for the erythrohydrobupropion and threohydrobupropion metabolites are similar to that of the hydroxybupropion metabolite. However, their elimination half-lives are longer, 33(±10) and 37 (±13) hours, respectively, and steady-state AUCs are 1.5 and 7 times that of bupropion, respectively. •Absorption (Drug B): Orphenadrine is almost completely absorbed in the gastrointestinal tract. •Volume of distribution (Drug A): No volume of distribution available •Volume of distribution (Drug B): No volume of distribution available •Protein binding (Drug A): In vitro tests show that bupropion is 84% bound to human plasma proteins at concentrations up to 200 mcg per mL. The extent of protein binding of the hydroxybupropion metabolite is similar to that for bupropion, whereas the extent of protein binding of the threohydrobupropion metabolite is about half that seen with bupropion. •Protein binding (Drug B): 95% •Metabolism (Drug A): Bupropion is extensively metabolized in humans. Three metabolites are active: hydroxybupropion, which is formed via hydroxylation of the tert-butyl group of bupropion, and the amino-alcohol isomers, threohydrobupropion and erythrohydrobupropion, which are formed via reduction of the carbonyl group. In vitro findings suggest that CYP2B6 is the principal isoenzyme involved in the formation of hydroxybupropion, while cytochrome P450 enzymes are not involved in the formation of threohydrobupropion. Hydroxybupropion has been shown to have the same affinity as bupropion for the norepinephrine transporter (NET) but approximately 50% of its antidepressant activity despite reaching concentrations of ~10-fold higher than that of the parent drug. Oxidation of the bupropion side chain results in the formation of a glycine conjugate of meta-chlorobenzoic acid, which is then excreted as the major urinary metabolite. The potency and toxicity of the metabolites relative to bupropion have not been fully characterized. However, it has been demonstrated in an antidepressant screening test in mice that hydroxybupropion is one-half as potent as bupropion, while threohydrobupropion and erythrohydrobupropion are 5-fold less potent than bupropion. This may be of clinical importance because the plasma concentrations of the metabolites are as high as or higher than those of bupropion. Bupropion and its metabolites exhibit linear kinetics following chronic administration of 300 to 450 mg per day. •Metabolism (Drug B): Biotransformation occurs mainly in the liver. Pharmacologically active metabolites are N-demethyl orphenadrine and N,N-didemethyl orphenadrine. •Route of elimination (Drug A): Bupropion is extensively metabolized in humans. Oxidation of the bupropion side chain results in the formation of a glycine conjugate of metachlorobenzoic acid, which is then excreted as the major urinary metabolite. Following oral administration of 200 mg of 14C-bupropion in humans, 87% and 10% of the radioactive dose were recovered in the urine and feces, respectively. However, the fraction of the oral dose of bupropion excreted unchanged was only 0.5%, a finding consistent with the extensive metabolism of bupropion. •Route of elimination (Drug B): No route of elimination available •Half-life (Drug A): 24 hours •Half-life (Drug B): 13-20 hours •Clearance (Drug A): No clearance available •Clearance (Drug B): No clearance available •Toxicity (Drug A): Symptoms of overdose include seizures, hallucinations, loss of consciousness, tachycardia, and cardiac arrest. •Toxicity (Drug B): Oral, mouse LD 50 = 100 mg/kg; oral, rat LD 50 = 255 mg/kg •Brand Names (Drug A): Aplenzin, Auvelity, Budeprion, Contrave, Forfivo, Wellbutrin, Zyban •Brand Names (Drug B): Norgesic, Norgesic Forte, Orfenace, Orphengesic •Synonyms (Drug A): No synonyms listed •Synonyms (Drug B): Orfenadrina Orphenadrine Orphenadrinum •Summary (Drug A): Bupropion is a norepinephrine and dopamine reuptake inhibitor used in the treatment of major depressive disorder (MDD), seasonal affective disorder (SAD), and as an aid to smoking cessation. •Summary (Drug B): Orphenadrine is a muscarinic antagonist used as an adjunct for the symptomatic relief of musculoskeletal pain and discomfort. Output: Despite the fact that these drugs are sometimes used in combination to treat depression in Parkinson's disease3, the administration of bupropion with anti-Parkinson drugs may lead to central nervous system toxicity. Bupropion is considered a norepinephrine-dopamine reuptake inhibitor, is found to occupy the DAT dopamine transporter, and acts as a dopamine agonist. Additive effects of these dopaminergic drugs may produce excess dopaminergic activity. Agitation, restlessness, tremor, ataxia, gait disturbance, and dizziness are some examples of effects that may occur from concurrent administration. The severity of the interaction is moderate.

Does Bupropion and Oseltamivir interact?

•Drug A: Bupropion •Drug B: Oseltamivir •Severity: MINOR •Description: Oseltamivir may decrease the excretion rate of Bupropion which could result in a higher serum level. •Extended Description: The renal excretion of drugs is the overall result of a combination of kidney processes that include glomerular filtration, passive diffusion, tubular secretion, and tubular reabsorption. Since two of these mechanisms - tubular secretion and reabsorption - are saturable processes , they are consequently susceptible to competition between multiple substrates excreted by the kidneys. If two or more medications that are mainly renally excreted are co-administered, they may compete for renal elimination; there is a large likelihood that one agent may "out-compete" or saturate the renal excretion mechanisms before the other concomitantly administered agent(s) are excreted. As a result, the elimination of these other concurrently administered agents may be inhibited or otherwise delayed, which could lead to increases in their serum concentrations and the risk, incidence, and/or severity of adverse effects associated with the exposure to such drugs. •Indication (Drug A): Bupropion is indicated for the treatment of major depressive disorder (MDD), seasonal affective disorder (SAD), and as an aid to smoking cessation. When used in combination with naltrexone as the marketed product ContraveⓇ, bupropion is indicated as an adjunct to a reduced-calorie diet and increased physical activity for chronic weight management in adults with an initial body mass index (BMI) of: 30 kg/m^2 or greater (obese) or 27 kg/m^2 or greater (overweight) in the presence of at least one weight-related comorbid condition (e.g., hypertension, type 2 diabetes mellitus, or dyslipidemia). Bupropion is also used off-label as a first-line treatment in patients with ADHD and comorbid bipolar disorder when used as an adjunct to mood stabilizers. •Indication (Drug B): According to FDA prescribing information, oseltamivir is indicated for the treatment of acute, uncomplicated illness due to influenza A and B infection in patients 2 weeks of age and older who have been symptomatic for no more than 48 hours. In particular, this agent is indicated in adults and children including full-term neonates who present with symptoms typical of influenza when influenza virus is circulating in the community. Efficacy has been demonstrated when treatment is initiated within two days of the first onset of symptoms. Oseltamivir is also indicated for the prophylaxis of influenza in patients one year and older. Specifically, post-exposure prevention in individuals one year of age or older following contact with a clinically diagnosed influenza case when influenza virus is circulating in the community qualifies for such prophylactic therapy. Oseltamivir would only be indicated for post-exposure prevention of influenza in infants less than 1 year of age during a pandemic influenza outbreak. •Pharmacodynamics (Drug A): Bupropion is chemically unrelated to tricyclic, tetracyclic, selective serotonin re-uptake inhibitors, or other known antidepressant agents. Compared to classical tricyclic antidepressants, Bupropion is a relatively weak inhibitor of the neuronal uptake of norepinephrine and dopamine. In addition, Bupropion does not inhibit monoamine oxidase. Bupropion has been found to be essentially inactive at the serotonin transporter (SERT)(IC50 >10 000 nM), however both bupropion and its primary metabolite hydroxybupropion have been found to block the function of cation-selective serotonin type 3A receptors (5-HT3ARs). Bupropion produces dose-related central nervous system (CNS) stimulant effects in animals, as evidenced by increased locomotor activity, increased rates of responding in various schedule-controlled operant behaviour tasks, and, at high doses, induction of mild stereotyped behaviour. Due to these stimulant effects and selective activity at dopamine and norepinephrine receptors, bupropion has been identified as having an abuse potential. Bupropion has a similar structure to the controlled substance Cathinone, and has been identified as having mild amphetamine-like activity, particularly when inhaled or injected. Bupropion is also known to lower the seizure threshold, making any pre-existing seizure conditions a contraindication to its use. This risk is exacerbated when bupropion is combined with other drugs or substances that lower the seizure threshold, such as cocaine, or in clinical situations that would increase the risk of a seizure such as abrupt alcohol or benzodiazepine withdrawal. As norepinephrine has been shown to have anticonvulsant properties, bupropion's inhibitory effects on NET are thought to contribute to its pro-convulsant activity. Bupropion has been shown to increase blood pressure and pose a risk for exacerbation of unmanaged or pre-existing hypertension, however, clinical trials of bupropion in smokers with CVD have not identified an increased incidence of CV events including stroke or heart attack. In clinical trials, the mean increase in systolic blood pressure associated with the use of bupropion was found to be 1.3 mmHg. •Pharmacodynamics (Drug B): There have been postmarketing reports of delirium and abnormal behavior leading to injury, and in some cases resulting in fatal outcomes, in patients with influenza who were receiving oseltamivir. Because these events were reported voluntarily during clinical practice, estimates of frequency cannot be made but they appear to be uncommon based on oseltamivir. These events were reported primarily among pediatric patients and often had an abrupt onset and rapid resolution. The contribution of oseltamivir to these events has not been established. Influenza can be associated with a variety of neurologic and behavioral symptoms that can include events such as hallucinations, delirium, and abnormal behavior, in some cases resulting in fatal outcomes. These events may occur in the setting of encephalitis or encephalopathy but can occur without obvious severe disease. •Mechanism of action (Drug A): Bupropion is a norepinephrine/dopamine-reuptake inhibitor (NDRI) that exerts its pharmacological effects by weakly inhibiting the enzymes involved in the uptake of the neurotransmitters norepinephrine and dopamine from the synaptic cleft, therefore prolonging their duration of action within the neuronal synapse and the downstream effects of these neurotransmitters. More specifically, bupropion binds to the norepinephrine transporter (NET) and the dopamine transporter (DAT). Bupropion was originally classified as an "atypical" antidepressant because it does not exert the same effects as the classical antidepressants such as Monoamine Oxidase Inhibitors (MAOIs), Tricyclic Antidepressants (TCAs), or Selective Serotonin Reuptake Inhibitors (SSRIs). While it has comparable effectiveness to typical first-line options for the treatment of depression such as SSRIs, bupropion is a unique option for the treatment of MDD as it lacks any clinically relevant serotonergic effects, typical of other mood medications, or any effects on histamine or adrenaline receptors. Lack of activity at these receptors results in a more tolerable side effect profile; bupropion is less likely to cause sexual side effects, sedation, or weight gain as compared to SSRIs or TCAs, for example. When used as an aid to smoking cessation, bupropion is thought to confer its anti-craving and anti-withdrawal effects by inhibiting dopamine reuptake, which is thought to be involved in the reward pathways associated with nicotine, and through the antagonism of the nicotinic acetylcholinergic receptor (AChR), thereby blunting the effects of nicotine. Furthermore, the stimulatory effects produced by bupropion in the central nervous system are similar to nicotine's effects, making low doses of bupropion a suitable option as a nicotine substitute. When used in combination with naltrexone in the marketed product ContraveⓇ for chronic weight management, the two components are thought to have effects on areas of the brain involved in the regulation of food intake. This includes the hypothalamus, which is involved in appetite regulation, and the mesolimbic dopamine circuit, which is involved in reward pathways. Studies have shown that the combined activity of bupropion and naltrexone increase the firing rate of hypothalamic pro-opiomelanocortin (POMC) neurons and blockade of opioid receptor-mediated POMC auto-inhibition, which are associated with a reduction in food intake and increased energy expenditure. This combination was also found to reduce food intake when injected directly into the ventral tegmental area of the mesolimbic circuit in mice, which is an area associated with the regulation of reward pathways. •Mechanism of action (Drug B): Oseltamivir phosphate is a pro-drug of the active metabolite (oseltamivir carboxylate) which is a potent and selective inhibitor of influenza virus neuraminidase enzymes, which are glycoproteins found on the virion surface. Viral neuraminidase enzyme activity is important for viral entry into uninfected cells, for the release of recently formed virus particles from infected cells, and for the further spread of the infectious virus in the body. Oseltamivir activity reduces viral shedding and infectivity. Oseltamivir is effective agaisnt viral neuraminidases of influenza A (including pandemic H1N1) and influenza B. •Absorption (Drug A): Bupropion is currently available in 3 distinct, but bioequivalent formulations: immediate release (IR), sustained-release (SR), and extended-release (XL). Immediate Release Formulation In humans, following oral administration of bupropion hydrochloride tablets, peak plasma bupropion concentrations are usually achieved within 2 hours. IR formulations provide a short duration of action and are therefore generally dosed three times per day. Sustained Release Formulation In humans, following oral administration of bupropion hydrochloride sustained-release tablets (SR), peak plasma concentration (Cmax) of bupropion is usually achieved within 3 hours. SR formulations provide a 12-hour extended release of medication and are therefore generally dosed twice per day. Extended Release Formulation Following single oral administration of bupropion hydrochloride extended-release tablets (XL) to healthy volunteers, the median time to peak plasma concentrations for bupropion was approximately 5 hours. The presence of food did not affect the peak concentration or area under the curve of bupropion. XL formulations provide a 24-hour extended release of medication and are therefore generally dosed once per day/ In a trial comparing chronic dosing with bupropion hydrochloride extended-release tablets (SR) 150 mg twice daily to bupropion immediate-release formulation 100 mg 3 times daily, the steady state Cmax for bupropion after bupropion hydrochloride sustained-release tablets (SR) administration was approximately 85% of those achieved after bupropion immediate-release formulation administration. Exposure (AUC) to bupropion was equivalent for both formulations. Bioequivalence was also demonstrated for all three major active metabolites (i.e., hydroxybupropion, threohydrobupropion and erythrohydrobupropion) for both Cmax and AUC. Thus, at steady state, bupropion hydrochloride sustained-release tablets (SR) given twice daily, and the immediate-release formulation of bupropion given 3 times daily, are essentially bioequivalent for both bupropion and the 3 quantitatively important metabolites. Furthermore, in a study comparing 14-day dosing with bupropion hydrochloride extended-release tablets (XL), 300 mg once-daily to the immediate-release formulation of bupropion at 100 mg 3 times daily, equivalence was demonstrated for peak plasma concentration and area under the curve for bupropion and the three metabolites (hydroxybupropion, threohydrobupropion, and erythrohydrobupropion). Additionally, in a study comparing 14-day dosing with bupropion hydrochloride extended-release tablets (XL) 300 mg once daily to the sustained-release formulation of bupropion at 150 mg 2 times daily, equivalence was demonstrated for peak plasma concentration and area under the curve for bupropion and the three metabolites. Bupropion hydrochloride extended-release tablets (SR) can be taken with or without food. Bupropion Cmax and AUC were increased by 11% to 35% and 16% to 19%, respectively, when bupropion hydrochloride extended-release tablets (SR) was administered with food to healthy volunteers in three trials. The food effect is not considered clinically significant. Following a single-dose administration of bupropion hydrochloride extended-release tablets (SR) in humans, Cmax of bupropion's metabolite hydroxybupropion occurs approximately 6 hours post-dose and is approximately 10 times the peak level of the parent drug at steady state. The elimination half-life of hydroxybupropion is approximately 20 (±5) hours and its AUC at steady state is about 17 times that of bupropion. The times to peak concentrations for the erythrohydrobupropion and threohydrobupropion metabolites are similar to that of the hydroxybupropion metabolite. However, their elimination half-lives are longer, 33(±10) and 37 (±13) hours, respectively, and steady-state AUCs are 1.5 and 7 times that of bupropion, respectively. •Absorption (Drug B): Oseltamivir is readily absorbed from the gastrointestinal tract after oral administration of oseltamivir phosphate and is extensively converted by predominantly hepatic esterases to the active metabolite oseltamivir carboxylate. At least 75 % of an oral dose reaches the systemic circulation as the active metabolite. Exposure to the pro-drug is less than 5 % relative to the active metabolite. Plasma concentrations of both pro-drug and active metabolite are proportional to dose and are unaffected by co-administration with food. Pharmacokinetic parameters following twice daily dosing of oseltamivir 75mg capsules are as follows: Cmax of oseltamivir and oseltamivir carboxylate were found to be 65ng/mL and 348ng/mL, respectively, while AUC (0-12h) of oseltamivir and oseltamivir carboxylate were found to be 112ng·h/mL and 2719ng·h/mL, respectively. •Volume of distribution (Drug A): No volume of distribution available •Volume of distribution (Drug B): The mean volume of distribution at steady state of the oseltamivir carboxylate ranges approximately between 23 and 26 liters in humans, a volume that is roughly equivalent to extracellular body fluid. Since neuraminidase activity is extracellular, oseltamivir carboxylate distributes to all sites of influenza virus spread. •Protein binding (Drug A): In vitro tests show that bupropion is 84% bound to human plasma proteins at concentrations up to 200 mcg per mL. The extent of protein binding of the hydroxybupropion metabolite is similar to that for bupropion, whereas the extent of protein binding of the threohydrobupropion metabolite is about half that seen with bupropion. •Protein binding (Drug B): The binding of the active oseltamivir carboxylate metabolite to human plasma protein is negligible at approximately 3 % while the binding of oseltamivir to human plasma protein is 42%, which is insufficient to cause significant displacement-based drug interactions. •Metabolism (Drug A): Bupropion is extensively metabolized in humans. Three metabolites are active: hydroxybupropion, which is formed via hydroxylation of the tert-butyl group of bupropion, and the amino-alcohol isomers, threohydrobupropion and erythrohydrobupropion, which are formed via reduction of the carbonyl group. In vitro findings suggest that CYP2B6 is the principal isoenzyme involved in the formation of hydroxybupropion, while cytochrome P450 enzymes are not involved in the formation of threohydrobupropion. Hydroxybupropion has been shown to have the same affinity as bupropion for the norepinephrine transporter (NET) but approximately 50% of its antidepressant activity despite reaching concentrations of ~10-fold higher than that of the parent drug. Oxidation of the bupropion side chain results in the formation of a glycine conjugate of meta-chlorobenzoic acid, which is then excreted as the major urinary metabolite. The potency and toxicity of the metabolites relative to bupropion have not been fully characterized. However, it has been demonstrated in an antidepressant screening test in mice that hydroxybupropion is one-half as potent as bupropion, while threohydrobupropion and erythrohydrobupropion are 5-fold less potent than bupropion. This may be of clinical importance because the plasma concentrations of the metabolites are as high as or higher than those of bupropion. Bupropion and its metabolites exhibit linear kinetics following chronic administration of 300 to 450 mg per day. •Metabolism (Drug B): Oseltamivir is extensively converted to the active metabolite, oseltamivir carboxylate, by esterases located predominantly in the liver. Oseltamivir carboxylate is not further metabolized. Neither oseltamivir nor oseltamivir carboxylate is a substrate for, or inhibitor of, cytochrome P450 isoforms. No phase 2 conjugates of either compound have been identified in vivo. •Route of elimination (Drug A): Bupropion is extensively metabolized in humans. Oxidation of the bupropion side chain results in the formation of a glycine conjugate of metachlorobenzoic acid, which is then excreted as the major urinary metabolite. Following oral administration of 200 mg of 14C-bupropion in humans, 87% and 10% of the radioactive dose were recovered in the urine and feces, respectively. However, the fraction of the oral dose of bupropion excreted unchanged was only 0.5%, a finding consistent with the extensive metabolism of bupropion. •Route of elimination (Drug B): Following absorption, oseltamivir is more than 90 % eliminated through conversion to oseltamivir carboxylate and subsequent elimination entirely through renal excretion. During clinical studies, less than 20 % of oral radiolabelled dose was found to be eliminated in faeces. •Half-life (Drug A): 24 hours •Half-life (Drug B): Plasma concentrations of oseltamivir declined with a half-life of 1 to 3 hours in most subjects after oral administration, although plasma concentrations of oseltamivir carboxylate declined with a half-life of 6 to 10 hours in most subjects after oral administration. •Clearance (Drug A): No clearance available •Clearance (Drug B): Renal clearance (18.8 l/h) of the drug exceeds glomerular filtration rate (7.5 l/h) indicating that tubular secretion occurs in addition to glomerular filtration. •Toxicity (Drug A): Symptoms of overdose include seizures, hallucinations, loss of consciousness, tachycardia, and cardiac arrest. •Toxicity (Drug B): Reports of overdoses with oseltamivir have been received from clinical trials and during postmarketing experience. In the majority of cases reporting overdose, no adverse reactions were reported. Adverse reactions reported following overdose were similar in nature to those observed with therapeutic doses of oseltamivir. •Brand Names (Drug A): Aplenzin, Auvelity, Budeprion, Contrave, Forfivo, Wellbutrin, Zyban •Brand Names (Drug B): Ebilfumin, Tamiflu •Synonyms (Drug A): No synonyms listed •Synonyms (Drug B): Oseltamivir Oséltamivir Oseltamivirum •Summary (Drug A): Bupropion is a norepinephrine and dopamine reuptake inhibitor used in the treatment of major depressive disorder (MDD), seasonal affective disorder (SAD), and as an aid to smoking cessation. •Summary (Drug B): Oseltamivir is a neuraminidase inhibitor used in the prophylaxis and treatment of influenza.

The renal excretion of drugs is the overall result of a combination of kidney processes that include glomerular filtration, passive diffusion, tubular secretion, and tubular reabsorption. Since two of these mechanisms - tubular secretion and reabsorption - are saturable processes , they are consequently susceptible to competition between multiple substrates excreted by the kidneys. If two or more medications that are mainly renally excreted are co-administered, they may compete for renal elimination; there is a large likelihood that one agent may "out-compete" or saturate the renal excretion mechanisms before the other concomitantly administered agent(s) are excreted. As a result, the elimination of these other concurrently administered agents may be inhibited or otherwise delayed, which could lead to increases in their serum concentrations and the risk, incidence, and/or severity of adverse effects associated with the exposure to such drugs. The severity of the interaction is minor.

Question: Does Bupropion and Oseltamivir interact? Information: •Drug A: Bupropion •Drug B: Oseltamivir •Severity: MINOR •Description: Oseltamivir may decrease the excretion rate of Bupropion which could result in a higher serum level. •Extended Description: The renal excretion of drugs is the overall result of a combination of kidney processes that include glomerular filtration, passive diffusion, tubular secretion, and tubular reabsorption. Since two of these mechanisms - tubular secretion and reabsorption - are saturable processes , they are consequently susceptible to competition between multiple substrates excreted by the kidneys. If two or more medications that are mainly renally excreted are co-administered, they may compete for renal elimination; there is a large likelihood that one agent may "out-compete" or saturate the renal excretion mechanisms before the other concomitantly administered agent(s) are excreted. As a result, the elimination of these other concurrently administered agents may be inhibited or otherwise delayed, which could lead to increases in their serum concentrations and the risk, incidence, and/or severity of adverse effects associated with the exposure to such drugs. •Indication (Drug A): Bupropion is indicated for the treatment of major depressive disorder (MDD), seasonal affective disorder (SAD), and as an aid to smoking cessation. When used in combination with naltrexone as the marketed product ContraveⓇ, bupropion is indicated as an adjunct to a reduced-calorie diet and increased physical activity for chronic weight management in adults with an initial body mass index (BMI) of: 30 kg/m^2 or greater (obese) or 27 kg/m^2 or greater (overweight) in the presence of at least one weight-related comorbid condition (e.g., hypertension, type 2 diabetes mellitus, or dyslipidemia). Bupropion is also used off-label as a first-line treatment in patients with ADHD and comorbid bipolar disorder when used as an adjunct to mood stabilizers. •Indication (Drug B): According to FDA prescribing information, oseltamivir is indicated for the treatment of acute, uncomplicated illness due to influenza A and B infection in patients 2 weeks of age and older who have been symptomatic for no more than 48 hours. In particular, this agent is indicated in adults and children including full-term neonates who present with symptoms typical of influenza when influenza virus is circulating in the community. Efficacy has been demonstrated when treatment is initiated within two days of the first onset of symptoms. Oseltamivir is also indicated for the prophylaxis of influenza in patients one year and older. Specifically, post-exposure prevention in individuals one year of age or older following contact with a clinically diagnosed influenza case when influenza virus is circulating in the community qualifies for such prophylactic therapy. Oseltamivir would only be indicated for post-exposure prevention of influenza in infants less than 1 year of age during a pandemic influenza outbreak. •Pharmacodynamics (Drug A): Bupropion is chemically unrelated to tricyclic, tetracyclic, selective serotonin re-uptake inhibitors, or other known antidepressant agents. Compared to classical tricyclic antidepressants, Bupropion is a relatively weak inhibitor of the neuronal uptake of norepinephrine and dopamine. In addition, Bupropion does not inhibit monoamine oxidase. Bupropion has been found to be essentially inactive at the serotonin transporter (SERT)(IC50 >10 000 nM), however both bupropion and its primary metabolite hydroxybupropion have been found to block the function of cation-selective serotonin type 3A receptors (5-HT3ARs). Bupropion produces dose-related central nervous system (CNS) stimulant effects in animals, as evidenced by increased locomotor activity, increased rates of responding in various schedule-controlled operant behaviour tasks, and, at high doses, induction of mild stereotyped behaviour. Due to these stimulant effects and selective activity at dopamine and norepinephrine receptors, bupropion has been identified as having an abuse potential. Bupropion has a similar structure to the controlled substance Cathinone, and has been identified as having mild amphetamine-like activity, particularly when inhaled or injected. Bupropion is also known to lower the seizure threshold, making any pre-existing seizure conditions a contraindication to its use. This risk is exacerbated when bupropion is combined with other drugs or substances that lower the seizure threshold, such as cocaine, or in clinical situations that would increase the risk of a seizure such as abrupt alcohol or benzodiazepine withdrawal. As norepinephrine has been shown to have anticonvulsant properties, bupropion's inhibitory effects on NET are thought to contribute to its pro-convulsant activity. Bupropion has been shown to increase blood pressure and pose a risk for exacerbation of unmanaged or pre-existing hypertension, however, clinical trials of bupropion in smokers with CVD have not identified an increased incidence of CV events including stroke or heart attack. In clinical trials, the mean increase in systolic blood pressure associated with the use of bupropion was found to be 1.3 mmHg. •Pharmacodynamics (Drug B): There have been postmarketing reports of delirium and abnormal behavior leading to injury, and in some cases resulting in fatal outcomes, in patients with influenza who were receiving oseltamivir. Because these events were reported voluntarily during clinical practice, estimates of frequency cannot be made but they appear to be uncommon based on oseltamivir. These events were reported primarily among pediatric patients and often had an abrupt onset and rapid resolution. The contribution of oseltamivir to these events has not been established. Influenza can be associated with a variety of neurologic and behavioral symptoms that can include events such as hallucinations, delirium, and abnormal behavior, in some cases resulting in fatal outcomes. These events may occur in the setting of encephalitis or encephalopathy but can occur without obvious severe disease. •Mechanism of action (Drug A): Bupropion is a norepinephrine/dopamine-reuptake inhibitor (NDRI) that exerts its pharmacological effects by weakly inhibiting the enzymes involved in the uptake of the neurotransmitters norepinephrine and dopamine from the synaptic cleft, therefore prolonging their duration of action within the neuronal synapse and the downstream effects of these neurotransmitters. More specifically, bupropion binds to the norepinephrine transporter (NET) and the dopamine transporter (DAT). Bupropion was originally classified as an "atypical" antidepressant because it does not exert the same effects as the classical antidepressants such as Monoamine Oxidase Inhibitors (MAOIs), Tricyclic Antidepressants (TCAs), or Selective Serotonin Reuptake Inhibitors (SSRIs). While it has comparable effectiveness to typical first-line options for the treatment of depression such as SSRIs, bupropion is a unique option for the treatment of MDD as it lacks any clinically relevant serotonergic effects, typical of other mood medications, or any effects on histamine or adrenaline receptors. Lack of activity at these receptors results in a more tolerable side effect profile; bupropion is less likely to cause sexual side effects, sedation, or weight gain as compared to SSRIs or TCAs, for example. When used as an aid to smoking cessation, bupropion is thought to confer its anti-craving and anti-withdrawal effects by inhibiting dopamine reuptake, which is thought to be involved in the reward pathways associated with nicotine, and through the antagonism of the nicotinic acetylcholinergic receptor (AChR), thereby blunting the effects of nicotine. Furthermore, the stimulatory effects produced by bupropion in the central nervous system are similar to nicotine's effects, making low doses of bupropion a suitable option as a nicotine substitute. When used in combination with naltrexone in the marketed product ContraveⓇ for chronic weight management, the two components are thought to have effects on areas of the brain involved in the regulation of food intake. This includes the hypothalamus, which is involved in appetite regulation, and the mesolimbic dopamine circuit, which is involved in reward pathways. Studies have shown that the combined activity of bupropion and naltrexone increase the firing rate of hypothalamic pro-opiomelanocortin (POMC) neurons and blockade of opioid receptor-mediated POMC auto-inhibition, which are associated with a reduction in food intake and increased energy expenditure. This combination was also found to reduce food intake when injected directly into the ventral tegmental area of the mesolimbic circuit in mice, which is an area associated with the regulation of reward pathways. •Mechanism of action (Drug B): Oseltamivir phosphate is a pro-drug of the active metabolite (oseltamivir carboxylate) which is a potent and selective inhibitor of influenza virus neuraminidase enzymes, which are glycoproteins found on the virion surface. Viral neuraminidase enzyme activity is important for viral entry into uninfected cells, for the release of recently formed virus particles from infected cells, and for the further spread of the infectious virus in the body. Oseltamivir activity reduces viral shedding and infectivity. Oseltamivir is effective agaisnt viral neuraminidases of influenza A (including pandemic H1N1) and influenza B. •Absorption (Drug A): Bupropion is currently available in 3 distinct, but bioequivalent formulations: immediate release (IR), sustained-release (SR), and extended-release (XL). Immediate Release Formulation In humans, following oral administration of bupropion hydrochloride tablets, peak plasma bupropion concentrations are usually achieved within 2 hours. IR formulations provide a short duration of action and are therefore generally dosed three times per day. Sustained Release Formulation In humans, following oral administration of bupropion hydrochloride sustained-release tablets (SR), peak plasma concentration (Cmax) of bupropion is usually achieved within 3 hours. SR formulations provide a 12-hour extended release of medication and are therefore generally dosed twice per day. Extended Release Formulation Following single oral administration of bupropion hydrochloride extended-release tablets (XL) to healthy volunteers, the median time to peak plasma concentrations for bupropion was approximately 5 hours. The presence of food did not affect the peak concentration or area under the curve of bupropion. XL formulations provide a 24-hour extended release of medication and are therefore generally dosed once per day/ In a trial comparing chronic dosing with bupropion hydrochloride extended-release tablets (SR) 150 mg twice daily to bupropion immediate-release formulation 100 mg 3 times daily, the steady state Cmax for bupropion after bupropion hydrochloride sustained-release tablets (SR) administration was approximately 85% of those achieved after bupropion immediate-release formulation administration. Exposure (AUC) to bupropion was equivalent for both formulations. Bioequivalence was also demonstrated for all three major active metabolites (i.e., hydroxybupropion, threohydrobupropion and erythrohydrobupropion) for both Cmax and AUC. Thus, at steady state, bupropion hydrochloride sustained-release tablets (SR) given twice daily, and the immediate-release formulation of bupropion given 3 times daily, are essentially bioequivalent for both bupropion and the 3 quantitatively important metabolites. Furthermore, in a study comparing 14-day dosing with bupropion hydrochloride extended-release tablets (XL), 300 mg once-daily to the immediate-release formulation of bupropion at 100 mg 3 times daily, equivalence was demonstrated for peak plasma concentration and area under the curve for bupropion and the three metabolites (hydroxybupropion, threohydrobupropion, and erythrohydrobupropion). Additionally, in a study comparing 14-day dosing with bupropion hydrochloride extended-release tablets (XL) 300 mg once daily to the sustained-release formulation of bupropion at 150 mg 2 times daily, equivalence was demonstrated for peak plasma concentration and area under the curve for bupropion and the three metabolites. Bupropion hydrochloride extended-release tablets (SR) can be taken with or without food. Bupropion Cmax and AUC were increased by 11% to 35% and 16% to 19%, respectively, when bupropion hydrochloride extended-release tablets (SR) was administered with food to healthy volunteers in three trials. The food effect is not considered clinically significant. Following a single-dose administration of bupropion hydrochloride extended-release tablets (SR) in humans, Cmax of bupropion's metabolite hydroxybupropion occurs approximately 6 hours post-dose and is approximately 10 times the peak level of the parent drug at steady state. The elimination half-life of hydroxybupropion is approximately 20 (±5) hours and its AUC at steady state is about 17 times that of bupropion. The times to peak concentrations for the erythrohydrobupropion and threohydrobupropion metabolites are similar to that of the hydroxybupropion metabolite. However, their elimination half-lives are longer, 33(±10) and 37 (±13) hours, respectively, and steady-state AUCs are 1.5 and 7 times that of bupropion, respectively. •Absorption (Drug B): Oseltamivir is readily absorbed from the gastrointestinal tract after oral administration of oseltamivir phosphate and is extensively converted by predominantly hepatic esterases to the active metabolite oseltamivir carboxylate. At least 75 % of an oral dose reaches the systemic circulation as the active metabolite. Exposure to the pro-drug is less than 5 % relative to the active metabolite. Plasma concentrations of both pro-drug and active metabolite are proportional to dose and are unaffected by co-administration with food. Pharmacokinetic parameters following twice daily dosing of oseltamivir 75mg capsules are as follows: Cmax of oseltamivir and oseltamivir carboxylate were found to be 65ng/mL and 348ng/mL, respectively, while AUC (0-12h) of oseltamivir and oseltamivir carboxylate were found to be 112ng·h/mL and 2719ng·h/mL, respectively. •Volume of distribution (Drug A): No volume of distribution available •Volume of distribution (Drug B): The mean volume of distribution at steady state of the oseltamivir carboxylate ranges approximately between 23 and 26 liters in humans, a volume that is roughly equivalent to extracellular body fluid. Since neuraminidase activity is extracellular, oseltamivir carboxylate distributes to all sites of influenza virus spread. •Protein binding (Drug A): In vitro tests show that bupropion is 84% bound to human plasma proteins at concentrations up to 200 mcg per mL. The extent of protein binding of the hydroxybupropion metabolite is similar to that for bupropion, whereas the extent of protein binding of the threohydrobupropion metabolite is about half that seen with bupropion. •Protein binding (Drug B): The binding of the active oseltamivir carboxylate metabolite to human plasma protein is negligible at approximately 3 % while the binding of oseltamivir to human plasma protein is 42%, which is insufficient to cause significant displacement-based drug interactions. •Metabolism (Drug A): Bupropion is extensively metabolized in humans. Three metabolites are active: hydroxybupropion, which is formed via hydroxylation of the tert-butyl group of bupropion, and the amino-alcohol isomers, threohydrobupropion and erythrohydrobupropion, which are formed via reduction of the carbonyl group. In vitro findings suggest that CYP2B6 is the principal isoenzyme involved in the formation of hydroxybupropion, while cytochrome P450 enzymes are not involved in the formation of threohydrobupropion. Hydroxybupropion has been shown to have the same affinity as bupropion for the norepinephrine transporter (NET) but approximately 50% of its antidepressant activity despite reaching concentrations of ~10-fold higher than that of the parent drug. Oxidation of the bupropion side chain results in the formation of a glycine conjugate of meta-chlorobenzoic acid, which is then excreted as the major urinary metabolite. The potency and toxicity of the metabolites relative to bupropion have not been fully characterized. However, it has been demonstrated in an antidepressant screening test in mice that hydroxybupropion is one-half as potent as bupropion, while threohydrobupropion and erythrohydrobupropion are 5-fold less potent than bupropion. This may be of clinical importance because the plasma concentrations of the metabolites are as high as or higher than those of bupropion. Bupropion and its metabolites exhibit linear kinetics following chronic administration of 300 to 450 mg per day. •Metabolism (Drug B): Oseltamivir is extensively converted to the active metabolite, oseltamivir carboxylate, by esterases located predominantly in the liver. Oseltamivir carboxylate is not further metabolized. Neither oseltamivir nor oseltamivir carboxylate is a substrate for, or inhibitor of, cytochrome P450 isoforms. No phase 2 conjugates of either compound have been identified in vivo. •Route of elimination (Drug A): Bupropion is extensively metabolized in humans. Oxidation of the bupropion side chain results in the formation of a glycine conjugate of metachlorobenzoic acid, which is then excreted as the major urinary metabolite. Following oral administration of 200 mg of 14C-bupropion in humans, 87% and 10% of the radioactive dose were recovered in the urine and feces, respectively. However, the fraction of the oral dose of bupropion excreted unchanged was only 0.5%, a finding consistent with the extensive metabolism of bupropion. •Route of elimination (Drug B): Following absorption, oseltamivir is more than 90 % eliminated through conversion to oseltamivir carboxylate and subsequent elimination entirely through renal excretion. During clinical studies, less than 20 % of oral radiolabelled dose was found to be eliminated in faeces. •Half-life (Drug A): 24 hours •Half-life (Drug B): Plasma concentrations of oseltamivir declined with a half-life of 1 to 3 hours in most subjects after oral administration, although plasma concentrations of oseltamivir carboxylate declined with a half-life of 6 to 10 hours in most subjects after oral administration. •Clearance (Drug A): No clearance available •Clearance (Drug B): Renal clearance (18.8 l/h) of the drug exceeds glomerular filtration rate (7.5 l/h) indicating that tubular secretion occurs in addition to glomerular filtration. •Toxicity (Drug A): Symptoms of overdose include seizures, hallucinations, loss of consciousness, tachycardia, and cardiac arrest. •Toxicity (Drug B): Reports of overdoses with oseltamivir have been received from clinical trials and during postmarketing experience. In the majority of cases reporting overdose, no adverse reactions were reported. Adverse reactions reported following overdose were similar in nature to those observed with therapeutic doses of oseltamivir. •Brand Names (Drug A): Aplenzin, Auvelity, Budeprion, Contrave, Forfivo, Wellbutrin, Zyban •Brand Names (Drug B): Ebilfumin, Tamiflu •Synonyms (Drug A): No synonyms listed •Synonyms (Drug B): Oseltamivir Oséltamivir Oseltamivirum •Summary (Drug A): Bupropion is a norepinephrine and dopamine reuptake inhibitor used in the treatment of major depressive disorder (MDD), seasonal affective disorder (SAD), and as an aid to smoking cessation. •Summary (Drug B): Oseltamivir is a neuraminidase inhibitor used in the prophylaxis and treatment of influenza. Output: The renal excretion of drugs is the overall result of a combination of kidney processes that include glomerular filtration, passive diffusion, tubular secretion, and tubular reabsorption. Since two of these mechanisms - tubular secretion and reabsorption - are saturable processes , they are consequently susceptible to competition between multiple substrates excreted by the kidneys. If two or more medications that are mainly renally excreted are co-administered, they may compete for renal elimination; there is a large likelihood that one agent may "out-compete" or saturate the renal excretion mechanisms before the other concomitantly administered agent(s) are excreted. As a result, the elimination of these other concurrently administered agents may be inhibited or otherwise delayed, which could lead to increases in their serum concentrations and the risk, incidence, and/or severity of adverse effects associated with the exposure to such drugs. The severity of the interaction is minor.

Does Bupropion and Osilodrostat interact?

•Drug A: Bupropion •Drug B: Osilodrostat •Severity: MODERATE •Description: The metabolism of Osilodrostat can be decreased when combined with Bupropion. •Extended Description: When a CYP2B6 substrate is coadministered with another CYP2B6 substrate, both substrates will invariably compete with each other to be metabolized by the limited quantities of CYP2B6 isoenzymes present in the body. When one substrate is subsequently capable of 'out-competing' the other, this other substrate will have its CYP2B6 facilitated metabolism stalled or otherwise decreased for a time, resulting in increased serum concentrations of this substrate and/or an increased risk, incidence, or severity of adverse effects associated with exposure to this substrate. •Indication (Drug A): Bupropion is indicated for the treatment of major depressive disorder (MDD), seasonal affective disorder (SAD), and as an aid to smoking cessation. When used in combination with naltrexone as the marketed product ContraveⓇ, bupropion is indicated as an adjunct to a reduced-calorie diet and increased physical activity for chronic weight management in adults with an initial body mass index (BMI) of: 30 kg/m^2 or greater (obese) or 27 kg/m^2 or greater (overweight) in the presence of at least one weight-related comorbid condition (e.g., hypertension, type 2 diabetes mellitus, or dyslipidemia). Bupropion is also used off-label as a first-line treatment in patients with ADHD and comorbid bipolar disorder when used as an adjunct to mood stabilizers. •Indication (Drug B): Osilodrostat is indicated for the treatment of adult patients with Cushing's disease for whom pituitary surgery is not an option or has not been curative. •Pharmacodynamics (Drug A): Bupropion is chemically unrelated to tricyclic, tetracyclic, selective serotonin re-uptake inhibitors, or other known antidepressant agents. Compared to classical tricyclic antidepressants, Bupropion is a relatively weak inhibitor of the neuronal uptake of norepinephrine and dopamine. In addition, Bupropion does not inhibit monoamine oxidase. Bupropion has been found to be essentially inactive at the serotonin transporter (SERT)(IC50 >10 000 nM), however both bupropion and its primary metabolite hydroxybupropion have been found to block the function of cation-selective serotonin type 3A receptors (5-HT3ARs). Bupropion produces dose-related central nervous system (CNS) stimulant effects in animals, as evidenced by increased locomotor activity, increased rates of responding in various schedule-controlled operant behaviour tasks, and, at high doses, induction of mild stereotyped behaviour. Due to these stimulant effects and selective activity at dopamine and norepinephrine receptors, bupropion has been identified as having an abuse potential. Bupropion has a similar structure to the controlled substance Cathinone, and has been identified as having mild amphetamine-like activity, particularly when inhaled or injected. Bupropion is also known to lower the seizure threshold, making any pre-existing seizure conditions a contraindication to its use. This risk is exacerbated when bupropion is combined with other drugs or substances that lower the seizure threshold, such as cocaine, or in clinical situations that would increase the risk of a seizure such as abrupt alcohol or benzodiazepine withdrawal. As norepinephrine has been shown to have anticonvulsant properties, bupropion's inhibitory effects on NET are thought to contribute to its pro-convulsant activity. Bupropion has been shown to increase blood pressure and pose a risk for exacerbation of unmanaged or pre-existing hypertension, however, clinical trials of bupropion in smokers with CVD have not identified an increased incidence of CV events including stroke or heart attack. In clinical trials, the mean increase in systolic blood pressure associated with the use of bupropion was found to be 1.3 mmHg. •Pharmacodynamics (Drug B): Osilodrostat lowers endogenous cortisol levels by inhibiting the enzyme that catalyzes the final step in cortisol synthesis. As endogenous cortisol levels function as a surrogate marker for drug effect, 24-hour urine free cortisol levels should be assessed 1-2x weekly during the initial titration stage and every 1-2 months thereafter to ensure cortisol levels remain physiologically appropriate. Osilodrostat is highly metabolized and requires dose adjustments in patient with hepatic dysfunction. Osilodrostat can cause a dose-dependent prolongation of the QTc interval and should be used with caution in patients with a higher baseline risk (e.g. concomitant QTc-prolonging medications, electrolyte abnormalities). Prior to beginning therapy, patients should have a baseline ECG and any electrolyte abnormalities (especially hypokalemia and/or hypomagnesemia) should be remedied. As osilodrostat halts cortisol synthesis at its final stage, its use can result in the accumulation of cortisol precursors, aldosterone precursors, and androgens. The accumulation of the cortisol precursor 11-deoxycorticosterone can activate mineralocorticoid receptors which may lead to hypokalemia, edema, or hypertension. Patients should be monitored for these symptoms as they are evidence of elevated 11-deoxycorticosterone levels, and for symptoms such as hirustism, acne, and hypertrichosis which may be suggestive of excessive circulating androgen levels. •Mechanism of action (Drug A): Bupropion is a norepinephrine/dopamine-reuptake inhibitor (NDRI) that exerts its pharmacological effects by weakly inhibiting the enzymes involved in the uptake of the neurotransmitters norepinephrine and dopamine from the synaptic cleft, therefore prolonging their duration of action within the neuronal synapse and the downstream effects of these neurotransmitters. More specifically, bupropion binds to the norepinephrine transporter (NET) and the dopamine transporter (DAT). Bupropion was originally classified as an "atypical" antidepressant because it does not exert the same effects as the classical antidepressants such as Monoamine Oxidase Inhibitors (MAOIs), Tricyclic Antidepressants (TCAs), or Selective Serotonin Reuptake Inhibitors (SSRIs). While it has comparable effectiveness to typical first-line options for the treatment of depression such as SSRIs, bupropion is a unique option for the treatment of MDD as it lacks any clinically relevant serotonergic effects, typical of other mood medications, or any effects on histamine or adrenaline receptors. Lack of activity at these receptors results in a more tolerable side effect profile; bupropion is less likely to cause sexual side effects, sedation, or weight gain as compared to SSRIs or TCAs, for example. When used as an aid to smoking cessation, bupropion is thought to confer its anti-craving and anti-withdrawal effects by inhibiting dopamine reuptake, which is thought to be involved in the reward pathways associated with nicotine, and through the antagonism of the nicotinic acetylcholinergic receptor (AChR), thereby blunting the effects of nicotine. Furthermore, the stimulatory effects produced by bupropion in the central nervous system are similar to nicotine's effects, making low doses of bupropion a suitable option as a nicotine substitute. When used in combination with naltrexone in the marketed product ContraveⓇ for chronic weight management, the two components are thought to have effects on areas of the brain involved in the regulation of food intake. This includes the hypothalamus, which is involved in appetite regulation, and the mesolimbic dopamine circuit, which is involved in reward pathways. Studies have shown that the combined activity of bupropion and naltrexone increase the firing rate of hypothalamic pro-opiomelanocortin (POMC) neurons and blockade of opioid receptor-mediated POMC auto-inhibition, which are associated with a reduction in food intake and increased energy expenditure. This combination was also found to reduce food intake when injected directly into the ventral tegmental area of the mesolimbic circuit in mice, which is an area associated with the regulation of reward pathways. •Mechanism of action (Drug B): Cushing’s syndrome is an endocrine disorder resulting from chronic and excessive exposure to glucocorticoids, the symptoms of which may include thinning of the skin and hair, weight gain, muscle weakness, and osteoporosis, as well a constellation of psychiatric, cardiovascular, and immunological deficiencies. Cushing’s syndrome is most commonly precipitated by exogenous treatment with supraphysiological doses of glucocorticoids such as those found in nasal sprays, skin creams, and inhalers. Cushing’s disease - another less common cause of Cushing’s syndrome - is generally the result of increased endogenous cortisol exposure due to excessive secretion of adrenocroticotrophic hormone (ACTH) from a pituitary adenoma. Osilodrostat is an inhibitor of 11β-hydroxylase (CYP11B1) and, to a lesser extent, aldosterone synthase (CYP11B2). The CYP11B1 enzyme is responsible for catalyzing the final step of cortisol synthesis - by inhibiting this enzyme, osilodrostat helps to normalize endogenous cortisol levels and alleviate symptoms of Cushing’s disease. •Absorption (Drug A): Bupropion is currently available in 3 distinct, but bioequivalent formulations: immediate release (IR), sustained-release (SR), and extended-release (XL). Immediate Release Formulation In humans, following oral administration of bupropion hydrochloride tablets, peak plasma bupropion concentrations are usually achieved within 2 hours. IR formulations provide a short duration of action and are therefore generally dosed three times per day. Sustained Release Formulation In humans, following oral administration of bupropion hydrochloride sustained-release tablets (SR), peak plasma concentration (Cmax) of bupropion is usually achieved within 3 hours. SR formulations provide a 12-hour extended release of medication and are therefore generally dosed twice per day. Extended Release Formulation Following single oral administration of bupropion hydrochloride extended-release tablets (XL) to healthy volunteers, the median time to peak plasma concentrations for bupropion was approximately 5 hours. The presence of food did not affect the peak concentration or area under the curve of bupropion. XL formulations provide a 24-hour extended release of medication and are therefore generally dosed once per day/ In a trial comparing chronic dosing with bupropion hydrochloride extended-release tablets (SR) 150 mg twice daily to bupropion immediate-release formulation 100 mg 3 times daily, the steady state Cmax for bupropion after bupropion hydrochloride sustained-release tablets (SR) administration was approximately 85% of those achieved after bupropion immediate-release formulation administration. Exposure (AUC) to bupropion was equivalent for both formulations. Bioequivalence was also demonstrated for all three major active metabolites (i.e., hydroxybupropion, threohydrobupropion and erythrohydrobupropion) for both Cmax and AUC. Thus, at steady state, bupropion hydrochloride sustained-release tablets (SR) given twice daily, and the immediate-release formulation of bupropion given 3 times daily, are essentially bioequivalent for both bupropion and the 3 quantitatively important metabolites. Furthermore, in a study comparing 14-day dosing with bupropion hydrochloride extended-release tablets (XL), 300 mg once-daily to the immediate-release formulation of bupropion at 100 mg 3 times daily, equivalence was demonstrated for peak plasma concentration and area under the curve for bupropion and the three metabolites (hydroxybupropion, threohydrobupropion, and erythrohydrobupropion). Additionally, in a study comparing 14-day dosing with bupropion hydrochloride extended-release tablets (XL) 300 mg once daily to the sustained-release formulation of bupropion at 150 mg 2 times daily, equivalence was demonstrated for peak plasma concentration and area under the curve for bupropion and the three metabolites. Bupropion hydrochloride extended-release tablets (SR) can be taken with or without food. Bupropion Cmax and AUC were increased by 11% to 35% and 16% to 19%, respectively, when bupropion hydrochloride extended-release tablets (SR) was administered with food to healthy volunteers in three trials. The food effect is not considered clinically significant. Following a single-dose administration of bupropion hydrochloride extended-release tablets (SR) in humans, Cmax of bupropion's metabolite hydroxybupropion occurs approximately 6 hours post-dose and is approximately 10 times the peak level of the parent drug at steady state. The elimination half-life of hydroxybupropion is approximately 20 (±5) hours and its AUC at steady state is about 17 times that of bupropion. The times to peak concentrations for the erythrohydrobupropion and threohydrobupropion metabolites are similar to that of the hydroxybupropion metabolite. However, their elimination half-lives are longer, 33(±10) and 37 (±13) hours, respectively, and steady-state AUCs are 1.5 and 7 times that of bupropion, respectively. •Absorption (Drug B): The oral absorption of osilodrostat is rapid, with a T max of approximately 1 hour, and assumed to be essentially complete. Exposure (i.e. AUC and C max ) increases slightly more than dose-proportionately over the standard dosing range. Coadministration of osilodrostat with food does not affect its pharmacokinetics to a clinically significant extent. Age and gender do not affect pharmacokinetics, but bioavailability and total exposure is higher (though not clinically significant) in patients of Asian descent. Exposure to osilodrostat is greater in patients with moderate-severe hepatic impairment - prescribing information recommends a starting dose of 1mg twice daily in patients with moderate hepatic impairment (Child-Pugh B) and a starting dose of 1mg each evening in patients with severe hepatic impairment (Child-Pugh C). •Volume of distribution (Drug A): No volume of distribution available •Volume of distribution (Drug B): The median apparent volume of distribution of osilodrostat is 100 L. •Protein binding (Drug A): In vitro tests show that bupropion is 84% bound to human plasma proteins at concentrations up to 200 mcg per mL. The extent of protein binding of the hydroxybupropion metabolite is similar to that for bupropion, whereas the extent of protein binding of the threohydrobupropion metabolite is about half that seen with bupropion. •Protein binding (Drug B): Both osilodrostat and its M34.5 metabolite are minimally protein-bound in plasma at less than 40%. The extent of protein-binding is independent of drug concentration. The specific plasma proteins to which osilodrostat binds have not been elucidated. •Metabolism (Drug A): Bupropion is extensively metabolized in humans. Three metabolites are active: hydroxybupropion, which is formed via hydroxylation of the tert-butyl group of bupropion, and the amino-alcohol isomers, threohydrobupropion and erythrohydrobupropion, which are formed via reduction of the carbonyl group. In vitro findings suggest that CYP2B6 is the principal isoenzyme involved in the formation of hydroxybupropion, while cytochrome P450 enzymes are not involved in the formation of threohydrobupropion. Hydroxybupropion has been shown to have the same affinity as bupropion for the norepinephrine transporter (NET) but approximately 50% of its antidepressant activity despite reaching concentrations of ~10-fold higher than that of the parent drug. Oxidation of the bupropion side chain results in the formation of a glycine conjugate of meta-chlorobenzoic acid, which is then excreted as the major urinary metabolite. The potency and toxicity of the metabolites relative to bupropion have not been fully characterized. However, it has been demonstrated in an antidepressant screening test in mice that hydroxybupropion is one-half as potent as bupropion, while threohydrobupropion and erythrohydrobupropion are 5-fold less potent than bupropion. This may be of clinical importance because the plasma concentrations of the metabolites are as high as or higher than those of bupropion. Bupropion and its metabolites exhibit linear kinetics following chronic administration of 300 to 450 mg per day. •Metabolism (Drug B): Osilodrostat is extensively metabolized - approximately 80% of an orally administered dose is excreted as metabolites, and this is the predominant means of drug clearance. The most abundant metabolites in plasma are M35.4 (di-oxygenated osilodrostat), M16.5, and M24.9 at 51%, 9%, and 7% of the administered dose, respectively. The M34.5 and M24.9 metabolites have longer half-lives than the parent drug which may lead to accumulation with twice-daily dosing. Of the thirteen metabolites observed in the urine, the most abundant are M16.5 (osilodrostat glucuronide), M22 (a glucuronide conjugate of M34.5), and M24.9 at 17%, 13%, and 11% of the administered dose, respectively. The M34.5 metabolite accounts for less than 1% of the dose excreted in urine, but its glucuronide conjugate (M22) accounts for approximately 13%. The biotransformation of osilodrostat is mediated by multiple cytochrome P450 (CYP) and UDP-glucuronosyltransferase (UGT) enzymes, though no single enzyme appears to contribute >25% to the total clearance. Of the total clearance, approximately 26% is CYP-mediated, 19% is UGT-mediated, and 50% is mediated by other enzymes. The formation of M34.5, the major metabolite of osilodrostat, is likely non-CYP-mediated. The formation of osilodrostat glucuronide (M16.5), its major urinary metabolite, is catalyzed by UGT1A4, UGT2B7, and UGT2B10. In vitro data suggest that none of the metabolites contribute to the therapeutic efficacy of osilodrostat, but the M34.5 metabolite has been implicated in the inhibition and/or induction of multiple enzymes and transporters. •Route of elimination (Drug A): Bupropion is extensively metabolized in humans. Oxidation of the bupropion side chain results in the formation of a glycine conjugate of metachlorobenzoic acid, which is then excreted as the major urinary metabolite. Following oral administration of 200 mg of 14C-bupropion in humans, 87% and 10% of the radioactive dose were recovered in the urine and feces, respectively. However, the fraction of the oral dose of bupropion excreted unchanged was only 0.5%, a finding consistent with the extensive metabolism of bupropion. •Route of elimination (Drug B): Following oral administration of radiolabeled osilodrostat, 90.6% of the radioactivity was eliminated in the urine with only 1.58% in the feces. Only 5.2% of the administered dose was eliminated in the urine as unchanged parent drug, suggesting that metabolism followed by urinary elimination is osildrostat's primary means of clearance. •Half-life (Drug A): 24 hours •Half-life (Drug B): The elimination half-life of osilodrostat is approximately 4 hours. •Clearance (Drug A): No clearance available •Clearance (Drug B): Data regarding the oral clearance of osilodrostat are not currently available. •Toxicity (Drug A): Symptoms of overdose include seizures, hallucinations, loss of consciousness, tachycardia, and cardiac arrest. •Toxicity (Drug B): As an inhibitor of cortisol synthesis, overdose with osilodrostat may result in severe hypocortisolism. Symptoms may include nausea, vomiting, fatigue, hypotension, abdominal pain, loss of appetite, dizziness, and syncope. Treatment of overdose should include assessment of cortisol levels and supplementation with exogenous corticosteroids as necessary, as well as careful monitoring of the patient's heart rhythm, blood glucose, electrolytes, and blood pressure. Toxicity related to its osilodrostat's mechanism of action is difficult to observe in animal test subjects as human receptor profiles and densities for osilodrostat targets differ in humans as compared to these animals - for this reason, toxicological data gleaned from animal trials is of uncertain clinical relevance in humans. •Brand Names (Drug A): Aplenzin, Auvelity, Budeprion, Contrave, Forfivo, Wellbutrin, Zyban •Brand Names (Drug B): Isturisa •Synonyms (Drug A): No synonyms listed •Synonyms (Drug B): No synonyms listed •Summary (Drug A): Bupropion is a norepinephrine and dopamine reuptake inhibitor used in the treatment of major depressive disorder (MDD), seasonal affective disorder (SAD), and as an aid to smoking cessation. •Summary (Drug B): Osilodrostat is an oral inhibitor of cortisol synthesis used to treat Cushing's disease by normalizing hypercortisolism.

When a CYP2B6 substrate is coadministered with another CYP2B6 substrate, both substrates will invariably compete with each other to be metabolized by the limited quantities of CYP2B6 isoenzymes present in the body. When one substrate is subsequently capable of 'out-competing' the other, this other substrate will have its CYP2B6 facilitated metabolism stalled or otherwise decreased for a time, resulting in increased serum concentrations of this substrate and/or an increased risk, incidence, or severity of adverse effects associated with exposure to this substrate. The severity of the interaction is moderate.

Question: Does Bupropion and Osilodrostat interact? Information: •Drug A: Bupropion •Drug B: Osilodrostat •Severity: MODERATE •Description: The metabolism of Osilodrostat can be decreased when combined with Bupropion. •Extended Description: When a CYP2B6 substrate is coadministered with another CYP2B6 substrate, both substrates will invariably compete with each other to be metabolized by the limited quantities of CYP2B6 isoenzymes present in the body. When one substrate is subsequently capable of 'out-competing' the other, this other substrate will have its CYP2B6 facilitated metabolism stalled or otherwise decreased for a time, resulting in increased serum concentrations of this substrate and/or an increased risk, incidence, or severity of adverse effects associated with exposure to this substrate. •Indication (Drug A): Bupropion is indicated for the treatment of major depressive disorder (MDD), seasonal affective disorder (SAD), and as an aid to smoking cessation. When used in combination with naltrexone as the marketed product ContraveⓇ, bupropion is indicated as an adjunct to a reduced-calorie diet and increased physical activity for chronic weight management in adults with an initial body mass index (BMI) of: 30 kg/m^2 or greater (obese) or 27 kg/m^2 or greater (overweight) in the presence of at least one weight-related comorbid condition (e.g., hypertension, type 2 diabetes mellitus, or dyslipidemia). Bupropion is also used off-label as a first-line treatment in patients with ADHD and comorbid bipolar disorder when used as an adjunct to mood stabilizers. •Indication (Drug B): Osilodrostat is indicated for the treatment of adult patients with Cushing's disease for whom pituitary surgery is not an option or has not been curative. •Pharmacodynamics (Drug A): Bupropion is chemically unrelated to tricyclic, tetracyclic, selective serotonin re-uptake inhibitors, or other known antidepressant agents. Compared to classical tricyclic antidepressants, Bupropion is a relatively weak inhibitor of the neuronal uptake of norepinephrine and dopamine. In addition, Bupropion does not inhibit monoamine oxidase. Bupropion has been found to be essentially inactive at the serotonin transporter (SERT)(IC50 >10 000 nM), however both bupropion and its primary metabolite hydroxybupropion have been found to block the function of cation-selective serotonin type 3A receptors (5-HT3ARs). Bupropion produces dose-related central nervous system (CNS) stimulant effects in animals, as evidenced by increased locomotor activity, increased rates of responding in various schedule-controlled operant behaviour tasks, and, at high doses, induction of mild stereotyped behaviour. Due to these stimulant effects and selective activity at dopamine and norepinephrine receptors, bupropion has been identified as having an abuse potential. Bupropion has a similar structure to the controlled substance Cathinone, and has been identified as having mild amphetamine-like activity, particularly when inhaled or injected. Bupropion is also known to lower the seizure threshold, making any pre-existing seizure conditions a contraindication to its use. This risk is exacerbated when bupropion is combined with other drugs or substances that lower the seizure threshold, such as cocaine, or in clinical situations that would increase the risk of a seizure such as abrupt alcohol or benzodiazepine withdrawal. As norepinephrine has been shown to have anticonvulsant properties, bupropion's inhibitory effects on NET are thought to contribute to its pro-convulsant activity. Bupropion has been shown to increase blood pressure and pose a risk for exacerbation of unmanaged or pre-existing hypertension, however, clinical trials of bupropion in smokers with CVD have not identified an increased incidence of CV events including stroke or heart attack. In clinical trials, the mean increase in systolic blood pressure associated with the use of bupropion was found to be 1.3 mmHg. •Pharmacodynamics (Drug B): Osilodrostat lowers endogenous cortisol levels by inhibiting the enzyme that catalyzes the final step in cortisol synthesis. As endogenous cortisol levels function as a surrogate marker for drug effect, 24-hour urine free cortisol levels should be assessed 1-2x weekly during the initial titration stage and every 1-2 months thereafter to ensure cortisol levels remain physiologically appropriate. Osilodrostat is highly metabolized and requires dose adjustments in patient with hepatic dysfunction. Osilodrostat can cause a dose-dependent prolongation of the QTc interval and should be used with caution in patients with a higher baseline risk (e.g. concomitant QTc-prolonging medications, electrolyte abnormalities). Prior to beginning therapy, patients should have a baseline ECG and any electrolyte abnormalities (especially hypokalemia and/or hypomagnesemia) should be remedied. As osilodrostat halts cortisol synthesis at its final stage, its use can result in the accumulation of cortisol precursors, aldosterone precursors, and androgens. The accumulation of the cortisol precursor 11-deoxycorticosterone can activate mineralocorticoid receptors which may lead to hypokalemia, edema, or hypertension. Patients should be monitored for these symptoms as they are evidence of elevated 11-deoxycorticosterone levels, and for symptoms such as hirustism, acne, and hypertrichosis which may be suggestive of excessive circulating androgen levels. •Mechanism of action (Drug A): Bupropion is a norepinephrine/dopamine-reuptake inhibitor (NDRI) that exerts its pharmacological effects by weakly inhibiting the enzymes involved in the uptake of the neurotransmitters norepinephrine and dopamine from the synaptic cleft, therefore prolonging their duration of action within the neuronal synapse and the downstream effects of these neurotransmitters. More specifically, bupropion binds to the norepinephrine transporter (NET) and the dopamine transporter (DAT). Bupropion was originally classified as an "atypical" antidepressant because it does not exert the same effects as the classical antidepressants such as Monoamine Oxidase Inhibitors (MAOIs), Tricyclic Antidepressants (TCAs), or Selective Serotonin Reuptake Inhibitors (SSRIs). While it has comparable effectiveness to typical first-line options for the treatment of depression such as SSRIs, bupropion is a unique option for the treatment of MDD as it lacks any clinically relevant serotonergic effects, typical of other mood medications, or any effects on histamine or adrenaline receptors. Lack of activity at these receptors results in a more tolerable side effect profile; bupropion is less likely to cause sexual side effects, sedation, or weight gain as compared to SSRIs or TCAs, for example. When used as an aid to smoking cessation, bupropion is thought to confer its anti-craving and anti-withdrawal effects by inhibiting dopamine reuptake, which is thought to be involved in the reward pathways associated with nicotine, and through the antagonism of the nicotinic acetylcholinergic receptor (AChR), thereby blunting the effects of nicotine. Furthermore, the stimulatory effects produced by bupropion in the central nervous system are similar to nicotine's effects, making low doses of bupropion a suitable option as a nicotine substitute. When used in combination with naltrexone in the marketed product ContraveⓇ for chronic weight management, the two components are thought to have effects on areas of the brain involved in the regulation of food intake. This includes the hypothalamus, which is involved in appetite regulation, and the mesolimbic dopamine circuit, which is involved in reward pathways. Studies have shown that the combined activity of bupropion and naltrexone increase the firing rate of hypothalamic pro-opiomelanocortin (POMC) neurons and blockade of opioid receptor-mediated POMC auto-inhibition, which are associated with a reduction in food intake and increased energy expenditure. This combination was also found to reduce food intake when injected directly into the ventral tegmental area of the mesolimbic circuit in mice, which is an area associated with the regulation of reward pathways. •Mechanism of action (Drug B): Cushing’s syndrome is an endocrine disorder resulting from chronic and excessive exposure to glucocorticoids, the symptoms of which may include thinning of the skin and hair, weight gain, muscle weakness, and osteoporosis, as well a constellation of psychiatric, cardiovascular, and immunological deficiencies. Cushing’s syndrome is most commonly precipitated by exogenous treatment with supraphysiological doses of glucocorticoids such as those found in nasal sprays, skin creams, and inhalers. Cushing’s disease - another less common cause of Cushing’s syndrome - is generally the result of increased endogenous cortisol exposure due to excessive secretion of adrenocroticotrophic hormone (ACTH) from a pituitary adenoma. Osilodrostat is an inhibitor of 11β-hydroxylase (CYP11B1) and, to a lesser extent, aldosterone synthase (CYP11B2). The CYP11B1 enzyme is responsible for catalyzing the final step of cortisol synthesis - by inhibiting this enzyme, osilodrostat helps to normalize endogenous cortisol levels and alleviate symptoms of Cushing’s disease. •Absorption (Drug A): Bupropion is currently available in 3 distinct, but bioequivalent formulations: immediate release (IR), sustained-release (SR), and extended-release (XL). Immediate Release Formulation In humans, following oral administration of bupropion hydrochloride tablets, peak plasma bupropion concentrations are usually achieved within 2 hours. IR formulations provide a short duration of action and are therefore generally dosed three times per day. Sustained Release Formulation In humans, following oral administration of bupropion hydrochloride sustained-release tablets (SR), peak plasma concentration (Cmax) of bupropion is usually achieved within 3 hours. SR formulations provide a 12-hour extended release of medication and are therefore generally dosed twice per day. Extended Release Formulation Following single oral administration of bupropion hydrochloride extended-release tablets (XL) to healthy volunteers, the median time to peak plasma concentrations for bupropion was approximately 5 hours. The presence of food did not affect the peak concentration or area under the curve of bupropion. XL formulations provide a 24-hour extended release of medication and are therefore generally dosed once per day/ In a trial comparing chronic dosing with bupropion hydrochloride extended-release tablets (SR) 150 mg twice daily to bupropion immediate-release formulation 100 mg 3 times daily, the steady state Cmax for bupropion after bupropion hydrochloride sustained-release tablets (SR) administration was approximately 85% of those achieved after bupropion immediate-release formulation administration. Exposure (AUC) to bupropion was equivalent for both formulations. Bioequivalence was also demonstrated for all three major active metabolites (i.e., hydroxybupropion, threohydrobupropion and erythrohydrobupropion) for both Cmax and AUC. Thus, at steady state, bupropion hydrochloride sustained-release tablets (SR) given twice daily, and the immediate-release formulation of bupropion given 3 times daily, are essentially bioequivalent for both bupropion and the 3 quantitatively important metabolites. Furthermore, in a study comparing 14-day dosing with bupropion hydrochloride extended-release tablets (XL), 300 mg once-daily to the immediate-release formulation of bupropion at 100 mg 3 times daily, equivalence was demonstrated for peak plasma concentration and area under the curve for bupropion and the three metabolites (hydroxybupropion, threohydrobupropion, and erythrohydrobupropion). Additionally, in a study comparing 14-day dosing with bupropion hydrochloride extended-release tablets (XL) 300 mg once daily to the sustained-release formulation of bupropion at 150 mg 2 times daily, equivalence was demonstrated for peak plasma concentration and area under the curve for bupropion and the three metabolites. Bupropion hydrochloride extended-release tablets (SR) can be taken with or without food. Bupropion Cmax and AUC were increased by 11% to 35% and 16% to 19%, respectively, when bupropion hydrochloride extended-release tablets (SR) was administered with food to healthy volunteers in three trials. The food effect is not considered clinically significant. Following a single-dose administration of bupropion hydrochloride extended-release tablets (SR) in humans, Cmax of bupropion's metabolite hydroxybupropion occurs approximately 6 hours post-dose and is approximately 10 times the peak level of the parent drug at steady state. The elimination half-life of hydroxybupropion is approximately 20 (±5) hours and its AUC at steady state is about 17 times that of bupropion. The times to peak concentrations for the erythrohydrobupropion and threohydrobupropion metabolites are similar to that of the hydroxybupropion metabolite. However, their elimination half-lives are longer, 33(±10) and 37 (±13) hours, respectively, and steady-state AUCs are 1.5 and 7 times that of bupropion, respectively. •Absorption (Drug B): The oral absorption of osilodrostat is rapid, with a T max of approximately 1 hour, and assumed to be essentially complete. Exposure (i.e. AUC and C max ) increases slightly more than dose-proportionately over the standard dosing range. Coadministration of osilodrostat with food does not affect its pharmacokinetics to a clinically significant extent. Age and gender do not affect pharmacokinetics, but bioavailability and total exposure is higher (though not clinically significant) in patients of Asian descent. Exposure to osilodrostat is greater in patients with moderate-severe hepatic impairment - prescribing information recommends a starting dose of 1mg twice daily in patients with moderate hepatic impairment (Child-Pugh B) and a starting dose of 1mg each evening in patients with severe hepatic impairment (Child-Pugh C). •Volume of distribution (Drug A): No volume of distribution available •Volume of distribution (Drug B): The median apparent volume of distribution of osilodrostat is 100 L. •Protein binding (Drug A): In vitro tests show that bupropion is 84% bound to human plasma proteins at concentrations up to 200 mcg per mL. The extent of protein binding of the hydroxybupropion metabolite is similar to that for bupropion, whereas the extent of protein binding of the threohydrobupropion metabolite is about half that seen with bupropion. •Protein binding (Drug B): Both osilodrostat and its M34.5 metabolite are minimally protein-bound in plasma at less than 40%. The extent of protein-binding is independent of drug concentration. The specific plasma proteins to which osilodrostat binds have not been elucidated. •Metabolism (Drug A): Bupropion is extensively metabolized in humans. Three metabolites are active: hydroxybupropion, which is formed via hydroxylation of the tert-butyl group of bupropion, and the amino-alcohol isomers, threohydrobupropion and erythrohydrobupropion, which are formed via reduction of the carbonyl group. In vitro findings suggest that CYP2B6 is the principal isoenzyme involved in the formation of hydroxybupropion, while cytochrome P450 enzymes are not involved in the formation of threohydrobupropion. Hydroxybupropion has been shown to have the same affinity as bupropion for the norepinephrine transporter (NET) but approximately 50% of its antidepressant activity despite reaching concentrations of ~10-fold higher than that of the parent drug. Oxidation of the bupropion side chain results in the formation of a glycine conjugate of meta-chlorobenzoic acid, which is then excreted as the major urinary metabolite. The potency and toxicity of the metabolites relative to bupropion have not been fully characterized. However, it has been demonstrated in an antidepressant screening test in mice that hydroxybupropion is one-half as potent as bupropion, while threohydrobupropion and erythrohydrobupropion are 5-fold less potent than bupropion. This may be of clinical importance because the plasma concentrations of the metabolites are as high as or higher than those of bupropion. Bupropion and its metabolites exhibit linear kinetics following chronic administration of 300 to 450 mg per day. •Metabolism (Drug B): Osilodrostat is extensively metabolized - approximately 80% of an orally administered dose is excreted as metabolites, and this is the predominant means of drug clearance. The most abundant metabolites in plasma are M35.4 (di-oxygenated osilodrostat), M16.5, and M24.9 at 51%, 9%, and 7% of the administered dose, respectively. The M34.5 and M24.9 metabolites have longer half-lives than the parent drug which may lead to accumulation with twice-daily dosing. Of the thirteen metabolites observed in the urine, the most abundant are M16.5 (osilodrostat glucuronide), M22 (a glucuronide conjugate of M34.5), and M24.9 at 17%, 13%, and 11% of the administered dose, respectively. The M34.5 metabolite accounts for less than 1% of the dose excreted in urine, but its glucuronide conjugate (M22) accounts for approximately 13%. The biotransformation of osilodrostat is mediated by multiple cytochrome P450 (CYP) and UDP-glucuronosyltransferase (UGT) enzymes, though no single enzyme appears to contribute >25% to the total clearance. Of the total clearance, approximately 26% is CYP-mediated, 19% is UGT-mediated, and 50% is mediated by other enzymes. The formation of M34.5, the major metabolite of osilodrostat, is likely non-CYP-mediated. The formation of osilodrostat glucuronide (M16.5), its major urinary metabolite, is catalyzed by UGT1A4, UGT2B7, and UGT2B10. In vitro data suggest that none of the metabolites contribute to the therapeutic efficacy of osilodrostat, but the M34.5 metabolite has been implicated in the inhibition and/or induction of multiple enzymes and transporters. •Route of elimination (Drug A): Bupropion is extensively metabolized in humans. Oxidation of the bupropion side chain results in the formation of a glycine conjugate of metachlorobenzoic acid, which is then excreted as the major urinary metabolite. Following oral administration of 200 mg of 14C-bupropion in humans, 87% and 10% of the radioactive dose were recovered in the urine and feces, respectively. However, the fraction of the oral dose of bupropion excreted unchanged was only 0.5%, a finding consistent with the extensive metabolism of bupropion. •Route of elimination (Drug B): Following oral administration of radiolabeled osilodrostat, 90.6% of the radioactivity was eliminated in the urine with only 1.58% in the feces. Only 5.2% of the administered dose was eliminated in the urine as unchanged parent drug, suggesting that metabolism followed by urinary elimination is osildrostat's primary means of clearance. •Half-life (Drug A): 24 hours •Half-life (Drug B): The elimination half-life of osilodrostat is approximately 4 hours. •Clearance (Drug A): No clearance available •Clearance (Drug B): Data regarding the oral clearance of osilodrostat are not currently available. •Toxicity (Drug A): Symptoms of overdose include seizures, hallucinations, loss of consciousness, tachycardia, and cardiac arrest. •Toxicity (Drug B): As an inhibitor of cortisol synthesis, overdose with osilodrostat may result in severe hypocortisolism. Symptoms may include nausea, vomiting, fatigue, hypotension, abdominal pain, loss of appetite, dizziness, and syncope. Treatment of overdose should include assessment of cortisol levels and supplementation with exogenous corticosteroids as necessary, as well as careful monitoring of the patient's heart rhythm, blood glucose, electrolytes, and blood pressure. Toxicity related to its osilodrostat's mechanism of action is difficult to observe in animal test subjects as human receptor profiles and densities for osilodrostat targets differ in humans as compared to these animals - for this reason, toxicological data gleaned from animal trials is of uncertain clinical relevance in humans. •Brand Names (Drug A): Aplenzin, Auvelity, Budeprion, Contrave, Forfivo, Wellbutrin, Zyban •Brand Names (Drug B): Isturisa •Synonyms (Drug A): No synonyms listed •Synonyms (Drug B): No synonyms listed •Summary (Drug A): Bupropion is a norepinephrine and dopamine reuptake inhibitor used in the treatment of major depressive disorder (MDD), seasonal affective disorder (SAD), and as an aid to smoking cessation. •Summary (Drug B): Osilodrostat is an oral inhibitor of cortisol synthesis used to treat Cushing's disease by normalizing hypercortisolism. Output: When a CYP2B6 substrate is coadministered with another CYP2B6 substrate, both substrates will invariably compete with each other to be metabolized by the limited quantities of CYP2B6 isoenzymes present in the body. When one substrate is subsequently capable of 'out-competing' the other, this other substrate will have its CYP2B6 facilitated metabolism stalled or otherwise decreased for a time, resulting in increased serum concentrations of this substrate and/or an increased risk, incidence, or severity of adverse effects associated with exposure to this substrate. The severity of the interaction is moderate.

Does Bupropion and Ospemifene interact?

•Drug A: Bupropion •Drug B: Ospemifene •Severity: MODERATE •Description: The metabolism of Ospemifene can be decreased when combined with Bupropion. •Extended Description: When a CYP2B6 substrate is coadministered with another CYP2B6 substrate, both substrates will invariably compete with each other to be metabolized by the limited quantities of CYP2B6 isoenzymes present in the body. When one substrate is subsequently capable of 'out-competing' the other, this other substrate will have its CYP2B6 facilitated metabolism stalled or otherwise decreased for a time, resulting in increased serum concentrations of this substrate and/or an increased risk, incidence, or severity of adverse effects associated with exposure to this substrate. •Indication (Drug A): Bupropion is indicated for the treatment of major depressive disorder (MDD), seasonal affective disorder (SAD), and as an aid to smoking cessation. When used in combination with naltrexone as the marketed product ContraveⓇ, bupropion is indicated as an adjunct to a reduced-calorie diet and increased physical activity for chronic weight management in adults with an initial body mass index (BMI) of: 30 kg/m^2 or greater (obese) or 27 kg/m^2 or greater (overweight) in the presence of at least one weight-related comorbid condition (e.g., hypertension, type 2 diabetes mellitus, or dyslipidemia). Bupropion is also used off-label as a first-line treatment in patients with ADHD and comorbid bipolar disorder when used as an adjunct to mood stabilizers. •Indication (Drug B): Ospemifene is indicated for the treatment of moderate to severe dyspareunia and vaginal dryness associated with menopause. •Pharmacodynamics (Drug A): Bupropion is chemically unrelated to tricyclic, tetracyclic, selective serotonin re-uptake inhibitors, or other known antidepressant agents. Compared to classical tricyclic antidepressants, Bupropion is a relatively weak inhibitor of the neuronal uptake of norepinephrine and dopamine. In addition, Bupropion does not inhibit monoamine oxidase. Bupropion has been found to be essentially inactive at the serotonin transporter (SERT)(IC50 >10 000 nM), however both bupropion and its primary metabolite hydroxybupropion have been found to block the function of cation-selective serotonin type 3A receptors (5-HT3ARs). Bupropion produces dose-related central nervous system (CNS) stimulant effects in animals, as evidenced by increased locomotor activity, increased rates of responding in various schedule-controlled operant behaviour tasks, and, at high doses, induction of mild stereotyped behaviour. Due to these stimulant effects and selective activity at dopamine and norepinephrine receptors, bupropion has been identified as having an abuse potential. Bupropion has a similar structure to the controlled substance Cathinone, and has been identified as having mild amphetamine-like activity, particularly when inhaled or injected. Bupropion is also known to lower the seizure threshold, making any pre-existing seizure conditions a contraindication to its use. This risk is exacerbated when bupropion is combined with other drugs or substances that lower the seizure threshold, such as cocaine, or in clinical situations that would increase the risk of a seizure such as abrupt alcohol or benzodiazepine withdrawal. As norepinephrine has been shown to have anticonvulsant properties, bupropion's inhibitory effects on NET are thought to contribute to its pro-convulsant activity. Bupropion has been shown to increase blood pressure and pose a risk for exacerbation of unmanaged or pre-existing hypertension, however, clinical trials of bupropion in smokers with CVD have not identified an increased incidence of CV events including stroke or heart attack. In clinical trials, the mean increase in systolic blood pressure associated with the use of bupropion was found to be 1.3 mmHg. •Pharmacodynamics (Drug B): The half maximal inhibitory concentration (IC50) for estrogen receptor (ER) alpha and beta are 0.8 μM and 1.7 μM, respectively. Ospemifene has potential uses in the management of osteoporosis in postmenopausal women. It interacts with osteoblasts and osteoclasts in such a way that it reduces bone turnover. It also has potential uses in the prevention of breast cancer. Studies suggest that ospemifene, in a dose-dependent manner, reduces the incidence of tumours. •Mechanism of action (Drug A): Bupropion is a norepinephrine/dopamine-reuptake inhibitor (NDRI) that exerts its pharmacological effects by weakly inhibiting the enzymes involved in the uptake of the neurotransmitters norepinephrine and dopamine from the synaptic cleft, therefore prolonging their duration of action within the neuronal synapse and the downstream effects of these neurotransmitters. More specifically, bupropion binds to the norepinephrine transporter (NET) and the dopamine transporter (DAT). Bupropion was originally classified as an "atypical" antidepressant because it does not exert the same effects as the classical antidepressants such as Monoamine Oxidase Inhibitors (MAOIs), Tricyclic Antidepressants (TCAs), or Selective Serotonin Reuptake Inhibitors (SSRIs). While it has comparable effectiveness to typical first-line options for the treatment of depression such as SSRIs, bupropion is a unique option for the treatment of MDD as it lacks any clinically relevant serotonergic effects, typical of other mood medications, or any effects on histamine or adrenaline receptors. Lack of activity at these receptors results in a more tolerable side effect profile; bupropion is less likely to cause sexual side effects, sedation, or weight gain as compared to SSRIs or TCAs, for example. When used as an aid to smoking cessation, bupropion is thought to confer its anti-craving and anti-withdrawal effects by inhibiting dopamine reuptake, which is thought to be involved in the reward pathways associated with nicotine, and through the antagonism of the nicotinic acetylcholinergic receptor (AChR), thereby blunting the effects of nicotine. Furthermore, the stimulatory effects produced by bupropion in the central nervous system are similar to nicotine's effects, making low doses of bupropion a suitable option as a nicotine substitute. When used in combination with naltrexone in the marketed product ContraveⓇ for chronic weight management, the two components are thought to have effects on areas of the brain involved in the regulation of food intake. This includes the hypothalamus, which is involved in appetite regulation, and the mesolimbic dopamine circuit, which is involved in reward pathways. Studies have shown that the combined activity of bupropion and naltrexone increase the firing rate of hypothalamic pro-opiomelanocortin (POMC) neurons and blockade of opioid receptor-mediated POMC auto-inhibition, which are associated with a reduction in food intake and increased energy expenditure. This combination was also found to reduce food intake when injected directly into the ventral tegmental area of the mesolimbic circuit in mice, which is an area associated with the regulation of reward pathways. •Mechanism of action (Drug B): Ospemifene is a next generation SERM (selective estrogen receptor modulator) that selectively binds to estrogen receptors and either stimulates or blocks estrogen's activity in different tissue types. It has an agonistic effect on the endometrium. •Absorption (Drug A): Bupropion is currently available in 3 distinct, but bioequivalent formulations: immediate release (IR), sustained-release (SR), and extended-release (XL). Immediate Release Formulation In humans, following oral administration of bupropion hydrochloride tablets, peak plasma bupropion concentrations are usually achieved within 2 hours. IR formulations provide a short duration of action and are therefore generally dosed three times per day. Sustained Release Formulation In humans, following oral administration of bupropion hydrochloride sustained-release tablets (SR), peak plasma concentration (Cmax) of bupropion is usually achieved within 3 hours. SR formulations provide a 12-hour extended release of medication and are therefore generally dosed twice per day. Extended Release Formulation Following single oral administration of bupropion hydrochloride extended-release tablets (XL) to healthy volunteers, the median time to peak plasma concentrations for bupropion was approximately 5 hours. The presence of food did not affect the peak concentration or area under the curve of bupropion. XL formulations provide a 24-hour extended release of medication and are therefore generally dosed once per day/ In a trial comparing chronic dosing with bupropion hydrochloride extended-release tablets (SR) 150 mg twice daily to bupropion immediate-release formulation 100 mg 3 times daily, the steady state Cmax for bupropion after bupropion hydrochloride sustained-release tablets (SR) administration was approximately 85% of those achieved after bupropion immediate-release formulation administration. Exposure (AUC) to bupropion was equivalent for both formulations. Bioequivalence was also demonstrated for all three major active metabolites (i.e., hydroxybupropion, threohydrobupropion and erythrohydrobupropion) for both Cmax and AUC. Thus, at steady state, bupropion hydrochloride sustained-release tablets (SR) given twice daily, and the immediate-release formulation of bupropion given 3 times daily, are essentially bioequivalent for both bupropion and the 3 quantitatively important metabolites. Furthermore, in a study comparing 14-day dosing with bupropion hydrochloride extended-release tablets (XL), 300 mg once-daily to the immediate-release formulation of bupropion at 100 mg 3 times daily, equivalence was demonstrated for peak plasma concentration and area under the curve for bupropion and the three metabolites (hydroxybupropion, threohydrobupropion, and erythrohydrobupropion). Additionally, in a study comparing 14-day dosing with bupropion hydrochloride extended-release tablets (XL) 300 mg once daily to the sustained-release formulation of bupropion at 150 mg 2 times daily, equivalence was demonstrated for peak plasma concentration and area under the curve for bupropion and the three metabolites. Bupropion hydrochloride extended-release tablets (SR) can be taken with or without food. Bupropion Cmax and AUC were increased by 11% to 35% and 16% to 19%, respectively, when bupropion hydrochloride extended-release tablets (SR) was administered with food to healthy volunteers in three trials. The food effect is not considered clinically significant. Following a single-dose administration of bupropion hydrochloride extended-release tablets (SR) in humans, Cmax of bupropion's metabolite hydroxybupropion occurs approximately 6 hours post-dose and is approximately 10 times the peak level of the parent drug at steady state. The elimination half-life of hydroxybupropion is approximately 20 (±5) hours and its AUC at steady state is about 17 times that of bupropion. The times to peak concentrations for the erythrohydrobupropion and threohydrobupropion metabolites are similar to that of the hydroxybupropion metabolite. However, their elimination half-lives are longer, 33(±10) and 37 (±13) hours, respectively, and steady-state AUCs are 1.5 and 7 times that of bupropion, respectively. •Absorption (Drug B): When a single oral dose of ospemifene 60 mg is given to postmenopausal women under fasted conditions, the pharmacokinetic parameters are as follows: Tmax = 2 hours (range of 1 - 8 hours); Cmax = 533 ng/mL; AUC (0-inf) = 4165 ng•hr/mL. When the same aforementioned dose is given to postmenopausal women under fed conditions, the pharmacokinetic parameters are as follows: Tmax = 2.5 hours (1 - 6 hours); Cmax = 1198 ng/mL; AUC (0-inf) = 7521 ng•hr/mL. Accumulation occurs following repeated doses. Time to steady state = 9 days. Although the bioavailability of ospemifene has not been formally evaluated, it is expected to have a low bioavailability because of its lipophilic nature. •Volume of distribution (Drug A): No volume of distribution available •Volume of distribution (Drug B): 448 L •Protein binding (Drug A): In vitro tests show that bupropion is 84% bound to human plasma proteins at concentrations up to 200 mcg per mL. The extent of protein binding of the hydroxybupropion metabolite is similar to that for bupropion, whereas the extent of protein binding of the threohydrobupropion metabolite is about half that seen with bupropion. •Protein binding (Drug B): >99% bound to serum proteins •Metabolism (Drug A): Bupropion is extensively metabolized in humans. Three metabolites are active: hydroxybupropion, which is formed via hydroxylation of the tert-butyl group of bupropion, and the amino-alcohol isomers, threohydrobupropion and erythrohydrobupropion, which are formed via reduction of the carbonyl group. In vitro findings suggest that CYP2B6 is the principal isoenzyme involved in the formation of hydroxybupropion, while cytochrome P450 enzymes are not involved in the formation of threohydrobupropion. Hydroxybupropion has been shown to have the same affinity as bupropion for the norepinephrine transporter (NET) but approximately 50% of its antidepressant activity despite reaching concentrations of ~10-fold higher than that of the parent drug. Oxidation of the bupropion side chain results in the formation of a glycine conjugate of meta-chlorobenzoic acid, which is then excreted as the major urinary metabolite. The potency and toxicity of the metabolites relative to bupropion have not been fully characterized. However, it has been demonstrated in an antidepressant screening test in mice that hydroxybupropion is one-half as potent as bupropion, while threohydrobupropion and erythrohydrobupropion are 5-fold less potent than bupropion. This may be of clinical importance because the plasma concentrations of the metabolites are as high as or higher than those of bupropion. Bupropion and its metabolites exhibit linear kinetics following chronic administration of 300 to 450 mg per day. •Metabolism (Drug B): Ospemifene is hepatically metabolized via CYP3A4, CYP2C9, CYP2C19, and CYP2B6. The major metabolite was 4-hydroxyospemifene, 25% of the parent compound will undergo this biotransformation. Other metabolites include 4'-hydroxy-ospemifene, <7% of the parent compound will undergo this biotransformation. In order of decreasing potency, ospemifene was suggested to be a weak inhibitor for CYP2B6, CYP2C9, CYP2C19, CYP2C8, CYP2D6 and CYP3A4. •Route of elimination (Drug A): Bupropion is extensively metabolized in humans. Oxidation of the bupropion side chain results in the formation of a glycine conjugate of metachlorobenzoic acid, which is then excreted as the major urinary metabolite. Following oral administration of 200 mg of 14C-bupropion in humans, 87% and 10% of the radioactive dose were recovered in the urine and feces, respectively. However, the fraction of the oral dose of bupropion excreted unchanged was only 0.5%, a finding consistent with the extensive metabolism of bupropion. •Route of elimination (Drug B): Following an oral administration of ospemifene, approximately 75% and 7% of the dose was excreted in feces and urine, respectively. Less than 0.2% of the ospemifene dose was excreted unchanged in urine. •Half-life (Drug A): 24 hours •Half-life (Drug B): Terminal half-life = 26 hours. •Clearance (Drug A): No clearance available •Clearance (Drug B): Total body clearance = 9.16 L/hr. •Toxicity (Drug A): Symptoms of overdose include seizures, hallucinations, loss of consciousness, tachycardia, and cardiac arrest. •Toxicity (Drug B): Adverse reactions (≥1 percent) include: hot flush, vaginal discharge, muscle spasms, genital discharge, hyperhidrosis. •Brand Names (Drug A): Aplenzin, Auvelity, Budeprion, Contrave, Forfivo, Wellbutrin, Zyban •Brand Names (Drug B): Osphena •Synonyms (Drug A): No synonyms listed •Synonyms (Drug B): Deamino-hydroxytoremifene Ospemifene Ospemifeno •Summary (Drug A): Bupropion is a norepinephrine and dopamine reuptake inhibitor used in the treatment of major depressive disorder (MDD), seasonal affective disorder (SAD), and as an aid to smoking cessation. •Summary (Drug B): Ospemifene is a non-hormonal estrogen receptor modulator (SERM) used to treat moderate to severe dyspareunia, a symptom of vulvar and vaginal atrophy, due to menopause.

When a CYP2B6 substrate is coadministered with another CYP2B6 substrate, both substrates will invariably compete with each other to be metabolized by the limited quantities of CYP2B6 isoenzymes present in the body. When one substrate is subsequently capable of 'out-competing' the other, this other substrate will have its CYP2B6 facilitated metabolism stalled or otherwise decreased for a time, resulting in increased serum concentrations of this substrate and/or an increased risk, incidence, or severity of adverse effects associated with exposure to this substrate. The severity of the interaction is moderate.

Question: Does Bupropion and Ospemifene interact? Information: •Drug A: Bupropion •Drug B: Ospemifene •Severity: MODERATE •Description: The metabolism of Ospemifene can be decreased when combined with Bupropion. •Extended Description: When a CYP2B6 substrate is coadministered with another CYP2B6 substrate, both substrates will invariably compete with each other to be metabolized by the limited quantities of CYP2B6 isoenzymes present in the body. When one substrate is subsequently capable of 'out-competing' the other, this other substrate will have its CYP2B6 facilitated metabolism stalled or otherwise decreased for a time, resulting in increased serum concentrations of this substrate and/or an increased risk, incidence, or severity of adverse effects associated with exposure to this substrate. •Indication (Drug A): Bupropion is indicated for the treatment of major depressive disorder (MDD), seasonal affective disorder (SAD), and as an aid to smoking cessation. When used in combination with naltrexone as the marketed product ContraveⓇ, bupropion is indicated as an adjunct to a reduced-calorie diet and increased physical activity for chronic weight management in adults with an initial body mass index (BMI) of: 30 kg/m^2 or greater (obese) or 27 kg/m^2 or greater (overweight) in the presence of at least one weight-related comorbid condition (e.g., hypertension, type 2 diabetes mellitus, or dyslipidemia). Bupropion is also used off-label as a first-line treatment in patients with ADHD and comorbid bipolar disorder when used as an adjunct to mood stabilizers. •Indication (Drug B): Ospemifene is indicated for the treatment of moderate to severe dyspareunia and vaginal dryness associated with menopause. •Pharmacodynamics (Drug A): Bupropion is chemically unrelated to tricyclic, tetracyclic, selective serotonin re-uptake inhibitors, or other known antidepressant agents. Compared to classical tricyclic antidepressants, Bupropion is a relatively weak inhibitor of the neuronal uptake of norepinephrine and dopamine. In addition, Bupropion does not inhibit monoamine oxidase. Bupropion has been found to be essentially inactive at the serotonin transporter (SERT)(IC50 >10 000 nM), however both bupropion and its primary metabolite hydroxybupropion have been found to block the function of cation-selective serotonin type 3A receptors (5-HT3ARs). Bupropion produces dose-related central nervous system (CNS) stimulant effects in animals, as evidenced by increased locomotor activity, increased rates of responding in various schedule-controlled operant behaviour tasks, and, at high doses, induction of mild stereotyped behaviour. Due to these stimulant effects and selective activity at dopamine and norepinephrine receptors, bupropion has been identified as having an abuse potential. Bupropion has a similar structure to the controlled substance Cathinone, and has been identified as having mild amphetamine-like activity, particularly when inhaled or injected. Bupropion is also known to lower the seizure threshold, making any pre-existing seizure conditions a contraindication to its use. This risk is exacerbated when bupropion is combined with other drugs or substances that lower the seizure threshold, such as cocaine, or in clinical situations that would increase the risk of a seizure such as abrupt alcohol or benzodiazepine withdrawal. As norepinephrine has been shown to have anticonvulsant properties, bupropion's inhibitory effects on NET are thought to contribute to its pro-convulsant activity. Bupropion has been shown to increase blood pressure and pose a risk for exacerbation of unmanaged or pre-existing hypertension, however, clinical trials of bupropion in smokers with CVD have not identified an increased incidence of CV events including stroke or heart attack. In clinical trials, the mean increase in systolic blood pressure associated with the use of bupropion was found to be 1.3 mmHg. •Pharmacodynamics (Drug B): The half maximal inhibitory concentration (IC50) for estrogen receptor (ER) alpha and beta are 0.8 μM and 1.7 μM, respectively. Ospemifene has potential uses in the management of osteoporosis in postmenopausal women. It interacts with osteoblasts and osteoclasts in such a way that it reduces bone turnover. It also has potential uses in the prevention of breast cancer. Studies suggest that ospemifene, in a dose-dependent manner, reduces the incidence of tumours. •Mechanism of action (Drug A): Bupropion is a norepinephrine/dopamine-reuptake inhibitor (NDRI) that exerts its pharmacological effects by weakly inhibiting the enzymes involved in the uptake of the neurotransmitters norepinephrine and dopamine from the synaptic cleft, therefore prolonging their duration of action within the neuronal synapse and the downstream effects of these neurotransmitters. More specifically, bupropion binds to the norepinephrine transporter (NET) and the dopamine transporter (DAT). Bupropion was originally classified as an "atypical" antidepressant because it does not exert the same effects as the classical antidepressants such as Monoamine Oxidase Inhibitors (MAOIs), Tricyclic Antidepressants (TCAs), or Selective Serotonin Reuptake Inhibitors (SSRIs). While it has comparable effectiveness to typical first-line options for the treatment of depression such as SSRIs, bupropion is a unique option for the treatment of MDD as it lacks any clinically relevant serotonergic effects, typical of other mood medications, or any effects on histamine or adrenaline receptors. Lack of activity at these receptors results in a more tolerable side effect profile; bupropion is less likely to cause sexual side effects, sedation, or weight gain as compared to SSRIs or TCAs, for example. When used as an aid to smoking cessation, bupropion is thought to confer its anti-craving and anti-withdrawal effects by inhibiting dopamine reuptake, which is thought to be involved in the reward pathways associated with nicotine, and through the antagonism of the nicotinic acetylcholinergic receptor (AChR), thereby blunting the effects of nicotine. Furthermore, the stimulatory effects produced by bupropion in the central nervous system are similar to nicotine's effects, making low doses of bupropion a suitable option as a nicotine substitute. When used in combination with naltrexone in the marketed product ContraveⓇ for chronic weight management, the two components are thought to have effects on areas of the brain involved in the regulation of food intake. This includes the hypothalamus, which is involved in appetite regulation, and the mesolimbic dopamine circuit, which is involved in reward pathways. Studies have shown that the combined activity of bupropion and naltrexone increase the firing rate of hypothalamic pro-opiomelanocortin (POMC) neurons and blockade of opioid receptor-mediated POMC auto-inhibition, which are associated with a reduction in food intake and increased energy expenditure. This combination was also found to reduce food intake when injected directly into the ventral tegmental area of the mesolimbic circuit in mice, which is an area associated with the regulation of reward pathways. •Mechanism of action (Drug B): Ospemifene is a next generation SERM (selective estrogen receptor modulator) that selectively binds to estrogen receptors and either stimulates or blocks estrogen's activity in different tissue types. It has an agonistic effect on the endometrium. •Absorption (Drug A): Bupropion is currently available in 3 distinct, but bioequivalent formulations: immediate release (IR), sustained-release (SR), and extended-release (XL). Immediate Release Formulation In humans, following oral administration of bupropion hydrochloride tablets, peak plasma bupropion concentrations are usually achieved within 2 hours. IR formulations provide a short duration of action and are therefore generally dosed three times per day. Sustained Release Formulation In humans, following oral administration of bupropion hydrochloride sustained-release tablets (SR), peak plasma concentration (Cmax) of bupropion is usually achieved within 3 hours. SR formulations provide a 12-hour extended release of medication and are therefore generally dosed twice per day. Extended Release Formulation Following single oral administration of bupropion hydrochloride extended-release tablets (XL) to healthy volunteers, the median time to peak plasma concentrations for bupropion was approximately 5 hours. The presence of food did not affect the peak concentration or area under the curve of bupropion. XL formulations provide a 24-hour extended release of medication and are therefore generally dosed once per day/ In a trial comparing chronic dosing with bupropion hydrochloride extended-release tablets (SR) 150 mg twice daily to bupropion immediate-release formulation 100 mg 3 times daily, the steady state Cmax for bupropion after bupropion hydrochloride sustained-release tablets (SR) administration was approximately 85% of those achieved after bupropion immediate-release formulation administration. Exposure (AUC) to bupropion was equivalent for both formulations. Bioequivalence was also demonstrated for all three major active metabolites (i.e., hydroxybupropion, threohydrobupropion and erythrohydrobupropion) for both Cmax and AUC. Thus, at steady state, bupropion hydrochloride sustained-release tablets (SR) given twice daily, and the immediate-release formulation of bupropion given 3 times daily, are essentially bioequivalent for both bupropion and the 3 quantitatively important metabolites. Furthermore, in a study comparing 14-day dosing with bupropion hydrochloride extended-release tablets (XL), 300 mg once-daily to the immediate-release formulation of bupropion at 100 mg 3 times daily, equivalence was demonstrated for peak plasma concentration and area under the curve for bupropion and the three metabolites (hydroxybupropion, threohydrobupropion, and erythrohydrobupropion). Additionally, in a study comparing 14-day dosing with bupropion hydrochloride extended-release tablets (XL) 300 mg once daily to the sustained-release formulation of bupropion at 150 mg 2 times daily, equivalence was demonstrated for peak plasma concentration and area under the curve for bupropion and the three metabolites. Bupropion hydrochloride extended-release tablets (SR) can be taken with or without food. Bupropion Cmax and AUC were increased by 11% to 35% and 16% to 19%, respectively, when bupropion hydrochloride extended-release tablets (SR) was administered with food to healthy volunteers in three trials. The food effect is not considered clinically significant. Following a single-dose administration of bupropion hydrochloride extended-release tablets (SR) in humans, Cmax of bupropion's metabolite hydroxybupropion occurs approximately 6 hours post-dose and is approximately 10 times the peak level of the parent drug at steady state. The elimination half-life of hydroxybupropion is approximately 20 (±5) hours and its AUC at steady state is about 17 times that of bupropion. The times to peak concentrations for the erythrohydrobupropion and threohydrobupropion metabolites are similar to that of the hydroxybupropion metabolite. However, their elimination half-lives are longer, 33(±10) and 37 (±13) hours, respectively, and steady-state AUCs are 1.5 and 7 times that of bupropion, respectively. •Absorption (Drug B): When a single oral dose of ospemifene 60 mg is given to postmenopausal women under fasted conditions, the pharmacokinetic parameters are as follows: Tmax = 2 hours (range of 1 - 8 hours); Cmax = 533 ng/mL; AUC (0-inf) = 4165 ng•hr/mL. When the same aforementioned dose is given to postmenopausal women under fed conditions, the pharmacokinetic parameters are as follows: Tmax = 2.5 hours (1 - 6 hours); Cmax = 1198 ng/mL; AUC (0-inf) = 7521 ng•hr/mL. Accumulation occurs following repeated doses. Time to steady state = 9 days. Although the bioavailability of ospemifene has not been formally evaluated, it is expected to have a low bioavailability because of its lipophilic nature. •Volume of distribution (Drug A): No volume of distribution available •Volume of distribution (Drug B): 448 L •Protein binding (Drug A): In vitro tests show that bupropion is 84% bound to human plasma proteins at concentrations up to 200 mcg per mL. The extent of protein binding of the hydroxybupropion metabolite is similar to that for bupropion, whereas the extent of protein binding of the threohydrobupropion metabolite is about half that seen with bupropion. •Protein binding (Drug B): >99% bound to serum proteins •Metabolism (Drug A): Bupropion is extensively metabolized in humans. Three metabolites are active: hydroxybupropion, which is formed via hydroxylation of the tert-butyl group of bupropion, and the amino-alcohol isomers, threohydrobupropion and erythrohydrobupropion, which are formed via reduction of the carbonyl group. In vitro findings suggest that CYP2B6 is the principal isoenzyme involved in the formation of hydroxybupropion, while cytochrome P450 enzymes are not involved in the formation of threohydrobupropion. Hydroxybupropion has been shown to have the same affinity as bupropion for the norepinephrine transporter (NET) but approximately 50% of its antidepressant activity despite reaching concentrations of ~10-fold higher than that of the parent drug. Oxidation of the bupropion side chain results in the formation of a glycine conjugate of meta-chlorobenzoic acid, which is then excreted as the major urinary metabolite. The potency and toxicity of the metabolites relative to bupropion have not been fully characterized. However, it has been demonstrated in an antidepressant screening test in mice that hydroxybupropion is one-half as potent as bupropion, while threohydrobupropion and erythrohydrobupropion are 5-fold less potent than bupropion. This may be of clinical importance because the plasma concentrations of the metabolites are as high as or higher than those of bupropion. Bupropion and its metabolites exhibit linear kinetics following chronic administration of 300 to 450 mg per day. •Metabolism (Drug B): Ospemifene is hepatically metabolized via CYP3A4, CYP2C9, CYP2C19, and CYP2B6. The major metabolite was 4-hydroxyospemifene, 25% of the parent compound will undergo this biotransformation. Other metabolites include 4'-hydroxy-ospemifene, <7% of the parent compound will undergo this biotransformation. In order of decreasing potency, ospemifene was suggested to be a weak inhibitor for CYP2B6, CYP2C9, CYP2C19, CYP2C8, CYP2D6 and CYP3A4. •Route of elimination (Drug A): Bupropion is extensively metabolized in humans. Oxidation of the bupropion side chain results in the formation of a glycine conjugate of metachlorobenzoic acid, which is then excreted as the major urinary metabolite. Following oral administration of 200 mg of 14C-bupropion in humans, 87% and 10% of the radioactive dose were recovered in the urine and feces, respectively. However, the fraction of the oral dose of bupropion excreted unchanged was only 0.5%, a finding consistent with the extensive metabolism of bupropion. •Route of elimination (Drug B): Following an oral administration of ospemifene, approximately 75% and 7% of the dose was excreted in feces and urine, respectively. Less than 0.2% of the ospemifene dose was excreted unchanged in urine. •Half-life (Drug A): 24 hours •Half-life (Drug B): Terminal half-life = 26 hours. •Clearance (Drug A): No clearance available •Clearance (Drug B): Total body clearance = 9.16 L/hr. •Toxicity (Drug A): Symptoms of overdose include seizures, hallucinations, loss of consciousness, tachycardia, and cardiac arrest. •Toxicity (Drug B): Adverse reactions (≥1 percent) include: hot flush, vaginal discharge, muscle spasms, genital discharge, hyperhidrosis. •Brand Names (Drug A): Aplenzin, Auvelity, Budeprion, Contrave, Forfivo, Wellbutrin, Zyban •Brand Names (Drug B): Osphena •Synonyms (Drug A): No synonyms listed •Synonyms (Drug B): Deamino-hydroxytoremifene Ospemifene Ospemifeno •Summary (Drug A): Bupropion is a norepinephrine and dopamine reuptake inhibitor used in the treatment of major depressive disorder (MDD), seasonal affective disorder (SAD), and as an aid to smoking cessation. •Summary (Drug B): Ospemifene is a non-hormonal estrogen receptor modulator (SERM) used to treat moderate to severe dyspareunia, a symptom of vulvar and vaginal atrophy, due to menopause. Output: When a CYP2B6 substrate is coadministered with another CYP2B6 substrate, both substrates will invariably compete with each other to be metabolized by the limited quantities of CYP2B6 isoenzymes present in the body. When one substrate is subsequently capable of 'out-competing' the other, this other substrate will have its CYP2B6 facilitated metabolism stalled or otherwise decreased for a time, resulting in increased serum concentrations of this substrate and/or an increased risk, incidence, or severity of adverse effects associated with exposure to this substrate. The severity of the interaction is moderate.

Does Bupropion and Oxacillin interact?

•Drug A: Bupropion •Drug B: Oxacillin •Severity: MINOR •Description: Oxacillin may decrease the excretion rate of Bupropion which could result in a higher serum level. •Extended Description: The renal excretion of drugs is the overall result of a combination of kidney processes that include glomerular filtration, passive diffusion, tubular secretion, and tubular reabsorption. Since two of these mechanisms - tubular secretion and reabsorption - are saturable processes , they are consequently susceptible to competition between multiple substrates excreted by the kidneys. If two or more medications that are mainly renally excreted are co-administered, they may compete for renal elimination; there is a large likelihood that one agent may "out-compete" or saturate the renal excretion mechanisms before the other concomitantly administered agent(s) are excreted. As a result, the elimination of these other concurrently administered agents may be inhibited or otherwise delayed, which could lead to increases in their serum concentrations and the risk, incidence, and/or severity of adverse effects associated with the exposure to such drugs. •Indication (Drug A): Bupropion is indicated for the treatment of major depressive disorder (MDD), seasonal affective disorder (SAD), and as an aid to smoking cessation. When used in combination with naltrexone as the marketed product ContraveⓇ, bupropion is indicated as an adjunct to a reduced-calorie diet and increased physical activity for chronic weight management in adults with an initial body mass index (BMI) of: 30 kg/m^2 or greater (obese) or 27 kg/m^2 or greater (overweight) in the presence of at least one weight-related comorbid condition (e.g., hypertension, type 2 diabetes mellitus, or dyslipidemia). Bupropion is also used off-label as a first-line treatment in patients with ADHD and comorbid bipolar disorder when used as an adjunct to mood stabilizers. •Indication (Drug B): Used in the treatment of resistant staphylococci infections. •Pharmacodynamics (Drug A): Bupropion is chemically unrelated to tricyclic, tetracyclic, selective serotonin re-uptake inhibitors, or other known antidepressant agents. Compared to classical tricyclic antidepressants, Bupropion is a relatively weak inhibitor of the neuronal uptake of norepinephrine and dopamine. In addition, Bupropion does not inhibit monoamine oxidase. Bupropion has been found to be essentially inactive at the serotonin transporter (SERT)(IC50 >10 000 nM), however both bupropion and its primary metabolite hydroxybupropion have been found to block the function of cation-selective serotonin type 3A receptors (5-HT3ARs). Bupropion produces dose-related central nervous system (CNS) stimulant effects in animals, as evidenced by increased locomotor activity, increased rates of responding in various schedule-controlled operant behaviour tasks, and, at high doses, induction of mild stereotyped behaviour. Due to these stimulant effects and selective activity at dopamine and norepinephrine receptors, bupropion has been identified as having an abuse potential. Bupropion has a similar structure to the controlled substance Cathinone, and has been identified as having mild amphetamine-like activity, particularly when inhaled or injected. Bupropion is also known to lower the seizure threshold, making any pre-existing seizure conditions a contraindication to its use. This risk is exacerbated when bupropion is combined with other drugs or substances that lower the seizure threshold, such as cocaine, or in clinical situations that would increase the risk of a seizure such as abrupt alcohol or benzodiazepine withdrawal. As norepinephrine has been shown to have anticonvulsant properties, bupropion's inhibitory effects on NET are thought to contribute to its pro-convulsant activity. Bupropion has been shown to increase blood pressure and pose a risk for exacerbation of unmanaged or pre-existing hypertension, however, clinical trials of bupropion in smokers with CVD have not identified an increased incidence of CV events including stroke or heart attack. In clinical trials, the mean increase in systolic blood pressure associated with the use of bupropion was found to be 1.3 mmHg. •Pharmacodynamics (Drug B): Oxacillin is a penicillin beta-lactam antibiotic used in the treatment of bacterial infections caused by susceptible, usually gram-positive, organisms. The name "penicillin" can either refer to several variants of penicillin available, or to the group of antibiotics derived from the penicillins. Oxacillin has in vitro activity against gram-positive and gram-negative aerobic and anaerobic bacteria. The bactericidal activity of Oxacillin results from the inhibition of cell wall synthesis and is mediated through Oxacillin binding to penicillin binding proteins (PBPs). Oxacillin is stable against hydrolysis by a variety of beta-lactamases, including penicillinases, and cephalosporinases and extended spectrum beta-lactamases. •Mechanism of action (Drug A): Bupropion is a norepinephrine/dopamine-reuptake inhibitor (NDRI) that exerts its pharmacological effects by weakly inhibiting the enzymes involved in the uptake of the neurotransmitters norepinephrine and dopamine from the synaptic cleft, therefore prolonging their duration of action within the neuronal synapse and the downstream effects of these neurotransmitters. More specifically, bupropion binds to the norepinephrine transporter (NET) and the dopamine transporter (DAT). Bupropion was originally classified as an "atypical" antidepressant because it does not exert the same effects as the classical antidepressants such as Monoamine Oxidase Inhibitors (MAOIs), Tricyclic Antidepressants (TCAs), or Selective Serotonin Reuptake Inhibitors (SSRIs). While it has comparable effectiveness to typical first-line options for the treatment of depression such as SSRIs, bupropion is a unique option for the treatment of MDD as it lacks any clinically relevant serotonergic effects, typical of other mood medications, or any effects on histamine or adrenaline receptors. Lack of activity at these receptors results in a more tolerable side effect profile; bupropion is less likely to cause sexual side effects, sedation, or weight gain as compared to SSRIs or TCAs, for example. When used as an aid to smoking cessation, bupropion is thought to confer its anti-craving and anti-withdrawal effects by inhibiting dopamine reuptake, which is thought to be involved in the reward pathways associated with nicotine, and through the antagonism of the nicotinic acetylcholinergic receptor (AChR), thereby blunting the effects of nicotine. Furthermore, the stimulatory effects produced by bupropion in the central nervous system are similar to nicotine's effects, making low doses of bupropion a suitable option as a nicotine substitute. When used in combination with naltrexone in the marketed product ContraveⓇ for chronic weight management, the two components are thought to have effects on areas of the brain involved in the regulation of food intake. This includes the hypothalamus, which is involved in appetite regulation, and the mesolimbic dopamine circuit, which is involved in reward pathways. Studies have shown that the combined activity of bupropion and naltrexone increase the firing rate of hypothalamic pro-opiomelanocortin (POMC) neurons and blockade of opioid receptor-mediated POMC auto-inhibition, which are associated with a reduction in food intake and increased energy expenditure. This combination was also found to reduce food intake when injected directly into the ventral tegmental area of the mesolimbic circuit in mice, which is an area associated with the regulation of reward pathways. •Mechanism of action (Drug B): By binding to specific penicillin-binding proteins (PBPs) located inside the bacterial cell wall, Oxacillin inhibits the third and last stage of bacterial cell wall synthesis. Cell lysis is then mediated by bacterial cell wall autolytic enzymes such as autolysins; it is possible that Oxacillin interferes with an autolysin inhibitor. •Absorption (Drug A): Bupropion is currently available in 3 distinct, but bioequivalent formulations: immediate release (IR), sustained-release (SR), and extended-release (XL). Immediate Release Formulation In humans, following oral administration of bupropion hydrochloride tablets, peak plasma bupropion concentrations are usually achieved within 2 hours. IR formulations provide a short duration of action and are therefore generally dosed three times per day. Sustained Release Formulation In humans, following oral administration of bupropion hydrochloride sustained-release tablets (SR), peak plasma concentration (Cmax) of bupropion is usually achieved within 3 hours. SR formulations provide a 12-hour extended release of medication and are therefore generally dosed twice per day. Extended Release Formulation Following single oral administration of bupropion hydrochloride extended-release tablets (XL) to healthy volunteers, the median time to peak plasma concentrations for bupropion was approximately 5 hours. The presence of food did not affect the peak concentration or area under the curve of bupropion. XL formulations provide a 24-hour extended release of medication and are therefore generally dosed once per day/ In a trial comparing chronic dosing with bupropion hydrochloride extended-release tablets (SR) 150 mg twice daily to bupropion immediate-release formulation 100 mg 3 times daily, the steady state Cmax for bupropion after bupropion hydrochloride sustained-release tablets (SR) administration was approximately 85% of those achieved after bupropion immediate-release formulation administration. Exposure (AUC) to bupropion was equivalent for both formulations. Bioequivalence was also demonstrated for all three major active metabolites (i.e., hydroxybupropion, threohydrobupropion and erythrohydrobupropion) for both Cmax and AUC. Thus, at steady state, bupropion hydrochloride sustained-release tablets (SR) given twice daily, and the immediate-release formulation of bupropion given 3 times daily, are essentially bioequivalent for both bupropion and the 3 quantitatively important metabolites. Furthermore, in a study comparing 14-day dosing with bupropion hydrochloride extended-release tablets (XL), 300 mg once-daily to the immediate-release formulation of bupropion at 100 mg 3 times daily, equivalence was demonstrated for peak plasma concentration and area under the curve for bupropion and the three metabolites (hydroxybupropion, threohydrobupropion, and erythrohydrobupropion). Additionally, in a study comparing 14-day dosing with bupropion hydrochloride extended-release tablets (XL) 300 mg once daily to the sustained-release formulation of bupropion at 150 mg 2 times daily, equivalence was demonstrated for peak plasma concentration and area under the curve for bupropion and the three metabolites. Bupropion hydrochloride extended-release tablets (SR) can be taken with or without food. Bupropion Cmax and AUC were increased by 11% to 35% and 16% to 19%, respectively, when bupropion hydrochloride extended-release tablets (SR) was administered with food to healthy volunteers in three trials. The food effect is not considered clinically significant. Following a single-dose administration of bupropion hydrochloride extended-release tablets (SR) in humans, Cmax of bupropion's metabolite hydroxybupropion occurs approximately 6 hours post-dose and is approximately 10 times the peak level of the parent drug at steady state. The elimination half-life of hydroxybupropion is approximately 20 (±5) hours and its AUC at steady state is about 17 times that of bupropion. The times to peak concentrations for the erythrohydrobupropion and threohydrobupropion metabolites are similar to that of the hydroxybupropion metabolite. However, their elimination half-lives are longer, 33(±10) and 37 (±13) hours, respectively, and steady-state AUCs are 1.5 and 7 times that of bupropion, respectively. •Absorption (Drug B): No absorption available •Volume of distribution (Drug A): No volume of distribution available •Volume of distribution (Drug B): No volume of distribution available •Protein binding (Drug A): In vitro tests show that bupropion is 84% bound to human plasma proteins at concentrations up to 200 mcg per mL. The extent of protein binding of the hydroxybupropion metabolite is similar to that for bupropion, whereas the extent of protein binding of the threohydrobupropion metabolite is about half that seen with bupropion. •Protein binding (Drug B): 94.2 +/- 2.1% (binds to serum protein, mainly albumin) •Metabolism (Drug A): Bupropion is extensively metabolized in humans. Three metabolites are active: hydroxybupropion, which is formed via hydroxylation of the tert-butyl group of bupropion, and the amino-alcohol isomers, threohydrobupropion and erythrohydrobupropion, which are formed via reduction of the carbonyl group. In vitro findings suggest that CYP2B6 is the principal isoenzyme involved in the formation of hydroxybupropion, while cytochrome P450 enzymes are not involved in the formation of threohydrobupropion. Hydroxybupropion has been shown to have the same affinity as bupropion for the norepinephrine transporter (NET) but approximately 50% of its antidepressant activity despite reaching concentrations of ~10-fold higher than that of the parent drug. Oxidation of the bupropion side chain results in the formation of a glycine conjugate of meta-chlorobenzoic acid, which is then excreted as the major urinary metabolite. The potency and toxicity of the metabolites relative to bupropion have not been fully characterized. However, it has been demonstrated in an antidepressant screening test in mice that hydroxybupropion is one-half as potent as bupropion, while threohydrobupropion and erythrohydrobupropion are 5-fold less potent than bupropion. This may be of clinical importance because the plasma concentrations of the metabolites are as high as or higher than those of bupropion. Bupropion and its metabolites exhibit linear kinetics following chronic administration of 300 to 450 mg per day. •Metabolism (Drug B): No metabolism available •Route of elimination (Drug A): Bupropion is extensively metabolized in humans. Oxidation of the bupropion side chain results in the formation of a glycine conjugate of metachlorobenzoic acid, which is then excreted as the major urinary metabolite. Following oral administration of 200 mg of 14C-bupropion in humans, 87% and 10% of the radioactive dose were recovered in the urine and feces, respectively. However, the fraction of the oral dose of bupropion excreted unchanged was only 0.5%, a finding consistent with the extensive metabolism of bupropion. •Route of elimination (Drug B): Oxacillin Sodium is rapidly excreted as unchanged drug in the urine by glomerular filtration and active tubular secretion. •Half-life (Drug A): 24 hours •Half-life (Drug B): 20 to 30 minutes •Clearance (Drug A): No clearance available •Clearance (Drug B): No clearance available •Toxicity (Drug A): Symptoms of overdose include seizures, hallucinations, loss of consciousness, tachycardia, and cardiac arrest. •Toxicity (Drug B): No toxicity available •Brand Names (Drug A): Aplenzin, Auvelity, Budeprion, Contrave, Forfivo, Wellbutrin, Zyban •Brand Names (Drug B): No brand names available •Synonyms (Drug A): No synonyms listed •Synonyms (Drug B): Ossacillina Oxacilina Oxacillin Oxacilline Oxacillinum Oxazocillin Oxazocilline •Summary (Drug A): Bupropion is a norepinephrine and dopamine reuptake inhibitor used in the treatment of major depressive disorder (MDD), seasonal affective disorder (SAD), and as an aid to smoking cessation. •Summary (Drug B): Oxacillin is a penicillin antibiotic used to treat a number of susceptible bacterial infections.

The renal excretion of drugs is the overall result of a combination of kidney processes that include glomerular filtration, passive diffusion, tubular secretion, and tubular reabsorption. Since two of these mechanisms - tubular secretion and reabsorption - are saturable processes , they are consequently susceptible to competition between multiple substrates excreted by the kidneys. If two or more medications that are mainly renally excreted are co-administered, they may compete for renal elimination; there is a large likelihood that one agent may "out-compete" or saturate the renal excretion mechanisms before the other concomitantly administered agent(s) are excreted. As a result, the elimination of these other concurrently administered agents may be inhibited or otherwise delayed, which could lead to increases in their serum concentrations and the risk, incidence, and/or severity of adverse effects associated with the exposure to such drugs. The severity of the interaction is minor.

Question: Does Bupropion and Oxacillin interact? Information: •Drug A: Bupropion •Drug B: Oxacillin •Severity: MINOR •Description: Oxacillin may decrease the excretion rate of Bupropion which could result in a higher serum level. •Extended Description: The renal excretion of drugs is the overall result of a combination of kidney processes that include glomerular filtration, passive diffusion, tubular secretion, and tubular reabsorption. Since two of these mechanisms - tubular secretion and reabsorption - are saturable processes , they are consequently susceptible to competition between multiple substrates excreted by the kidneys. If two or more medications that are mainly renally excreted are co-administered, they may compete for renal elimination; there is a large likelihood that one agent may "out-compete" or saturate the renal excretion mechanisms before the other concomitantly administered agent(s) are excreted. As a result, the elimination of these other concurrently administered agents may be inhibited or otherwise delayed, which could lead to increases in their serum concentrations and the risk, incidence, and/or severity of adverse effects associated with the exposure to such drugs. •Indication (Drug A): Bupropion is indicated for the treatment of major depressive disorder (MDD), seasonal affective disorder (SAD), and as an aid to smoking cessation. When used in combination with naltrexone as the marketed product ContraveⓇ, bupropion is indicated as an adjunct to a reduced-calorie diet and increased physical activity for chronic weight management in adults with an initial body mass index (BMI) of: 30 kg/m^2 or greater (obese) or 27 kg/m^2 or greater (overweight) in the presence of at least one weight-related comorbid condition (e.g., hypertension, type 2 diabetes mellitus, or dyslipidemia). Bupropion is also used off-label as a first-line treatment in patients with ADHD and comorbid bipolar disorder when used as an adjunct to mood stabilizers. •Indication (Drug B): Used in the treatment of resistant staphylococci infections. •Pharmacodynamics (Drug A): Bupropion is chemically unrelated to tricyclic, tetracyclic, selective serotonin re-uptake inhibitors, or other known antidepressant agents. Compared to classical tricyclic antidepressants, Bupropion is a relatively weak inhibitor of the neuronal uptake of norepinephrine and dopamine. In addition, Bupropion does not inhibit monoamine oxidase. Bupropion has been found to be essentially inactive at the serotonin transporter (SERT)(IC50 >10 000 nM), however both bupropion and its primary metabolite hydroxybupropion have been found to block the function of cation-selective serotonin type 3A receptors (5-HT3ARs). Bupropion produces dose-related central nervous system (CNS) stimulant effects in animals, as evidenced by increased locomotor activity, increased rates of responding in various schedule-controlled operant behaviour tasks, and, at high doses, induction of mild stereotyped behaviour. Due to these stimulant effects and selective activity at dopamine and norepinephrine receptors, bupropion has been identified as having an abuse potential. Bupropion has a similar structure to the controlled substance Cathinone, and has been identified as having mild amphetamine-like activity, particularly when inhaled or injected. Bupropion is also known to lower the seizure threshold, making any pre-existing seizure conditions a contraindication to its use. This risk is exacerbated when bupropion is combined with other drugs or substances that lower the seizure threshold, such as cocaine, or in clinical situations that would increase the risk of a seizure such as abrupt alcohol or benzodiazepine withdrawal. As norepinephrine has been shown to have anticonvulsant properties, bupropion's inhibitory effects on NET are thought to contribute to its pro-convulsant activity. Bupropion has been shown to increase blood pressure and pose a risk for exacerbation of unmanaged or pre-existing hypertension, however, clinical trials of bupropion in smokers with CVD have not identified an increased incidence of CV events including stroke or heart attack. In clinical trials, the mean increase in systolic blood pressure associated with the use of bupropion was found to be 1.3 mmHg. •Pharmacodynamics (Drug B): Oxacillin is a penicillin beta-lactam antibiotic used in the treatment of bacterial infections caused by susceptible, usually gram-positive, organisms. The name "penicillin" can either refer to several variants of penicillin available, or to the group of antibiotics derived from the penicillins. Oxacillin has in vitro activity against gram-positive and gram-negative aerobic and anaerobic bacteria. The bactericidal activity of Oxacillin results from the inhibition of cell wall synthesis and is mediated through Oxacillin binding to penicillin binding proteins (PBPs). Oxacillin is stable against hydrolysis by a variety of beta-lactamases, including penicillinases, and cephalosporinases and extended spectrum beta-lactamases. •Mechanism of action (Drug A): Bupropion is a norepinephrine/dopamine-reuptake inhibitor (NDRI) that exerts its pharmacological effects by weakly inhibiting the enzymes involved in the uptake of the neurotransmitters norepinephrine and dopamine from the synaptic cleft, therefore prolonging their duration of action within the neuronal synapse and the downstream effects of these neurotransmitters. More specifically, bupropion binds to the norepinephrine transporter (NET) and the dopamine transporter (DAT). Bupropion was originally classified as an "atypical" antidepressant because it does not exert the same effects as the classical antidepressants such as Monoamine Oxidase Inhibitors (MAOIs), Tricyclic Antidepressants (TCAs), or Selective Serotonin Reuptake Inhibitors (SSRIs). While it has comparable effectiveness to typical first-line options for the treatment of depression such as SSRIs, bupropion is a unique option for the treatment of MDD as it lacks any clinically relevant serotonergic effects, typical of other mood medications, or any effects on histamine or adrenaline receptors. Lack of activity at these receptors results in a more tolerable side effect profile; bupropion is less likely to cause sexual side effects, sedation, or weight gain as compared to SSRIs or TCAs, for example. When used as an aid to smoking cessation, bupropion is thought to confer its anti-craving and anti-withdrawal effects by inhibiting dopamine reuptake, which is thought to be involved in the reward pathways associated with nicotine, and through the antagonism of the nicotinic acetylcholinergic receptor (AChR), thereby blunting the effects of nicotine. Furthermore, the stimulatory effects produced by bupropion in the central nervous system are similar to nicotine's effects, making low doses of bupropion a suitable option as a nicotine substitute. When used in combination with naltrexone in the marketed product ContraveⓇ for chronic weight management, the two components are thought to have effects on areas of the brain involved in the regulation of food intake. This includes the hypothalamus, which is involved in appetite regulation, and the mesolimbic dopamine circuit, which is involved in reward pathways. Studies have shown that the combined activity of bupropion and naltrexone increase the firing rate of hypothalamic pro-opiomelanocortin (POMC) neurons and blockade of opioid receptor-mediated POMC auto-inhibition, which are associated with a reduction in food intake and increased energy expenditure. This combination was also found to reduce food intake when injected directly into the ventral tegmental area of the mesolimbic circuit in mice, which is an area associated with the regulation of reward pathways. •Mechanism of action (Drug B): By binding to specific penicillin-binding proteins (PBPs) located inside the bacterial cell wall, Oxacillin inhibits the third and last stage of bacterial cell wall synthesis. Cell lysis is then mediated by bacterial cell wall autolytic enzymes such as autolysins; it is possible that Oxacillin interferes with an autolysin inhibitor. •Absorption (Drug A): Bupropion is currently available in 3 distinct, but bioequivalent formulations: immediate release (IR), sustained-release (SR), and extended-release (XL). Immediate Release Formulation In humans, following oral administration of bupropion hydrochloride tablets, peak plasma bupropion concentrations are usually achieved within 2 hours. IR formulations provide a short duration of action and are therefore generally dosed three times per day. Sustained Release Formulation In humans, following oral administration of bupropion hydrochloride sustained-release tablets (SR), peak plasma concentration (Cmax) of bupropion is usually achieved within 3 hours. SR formulations provide a 12-hour extended release of medication and are therefore generally dosed twice per day. Extended Release Formulation Following single oral administration of bupropion hydrochloride extended-release tablets (XL) to healthy volunteers, the median time to peak plasma concentrations for bupropion was approximately 5 hours. The presence of food did not affect the peak concentration or area under the curve of bupropion. XL formulations provide a 24-hour extended release of medication and are therefore generally dosed once per day/ In a trial comparing chronic dosing with bupropion hydrochloride extended-release tablets (SR) 150 mg twice daily to bupropion immediate-release formulation 100 mg 3 times daily, the steady state Cmax for bupropion after bupropion hydrochloride sustained-release tablets (SR) administration was approximately 85% of those achieved after bupropion immediate-release formulation administration. Exposure (AUC) to bupropion was equivalent for both formulations. Bioequivalence was also demonstrated for all three major active metabolites (i.e., hydroxybupropion, threohydrobupropion and erythrohydrobupropion) for both Cmax and AUC. Thus, at steady state, bupropion hydrochloride sustained-release tablets (SR) given twice daily, and the immediate-release formulation of bupropion given 3 times daily, are essentially bioequivalent for both bupropion and the 3 quantitatively important metabolites. Furthermore, in a study comparing 14-day dosing with bupropion hydrochloride extended-release tablets (XL), 300 mg once-daily to the immediate-release formulation of bupropion at 100 mg 3 times daily, equivalence was demonstrated for peak plasma concentration and area under the curve for bupropion and the three metabolites (hydroxybupropion, threohydrobupropion, and erythrohydrobupropion). Additionally, in a study comparing 14-day dosing with bupropion hydrochloride extended-release tablets (XL) 300 mg once daily to the sustained-release formulation of bupropion at 150 mg 2 times daily, equivalence was demonstrated for peak plasma concentration and area under the curve for bupropion and the three metabolites. Bupropion hydrochloride extended-release tablets (SR) can be taken with or without food. Bupropion Cmax and AUC were increased by 11% to 35% and 16% to 19%, respectively, when bupropion hydrochloride extended-release tablets (SR) was administered with food to healthy volunteers in three trials. The food effect is not considered clinically significant. Following a single-dose administration of bupropion hydrochloride extended-release tablets (SR) in humans, Cmax of bupropion's metabolite hydroxybupropion occurs approximately 6 hours post-dose and is approximately 10 times the peak level of the parent drug at steady state. The elimination half-life of hydroxybupropion is approximately 20 (±5) hours and its AUC at steady state is about 17 times that of bupropion. The times to peak concentrations for the erythrohydrobupropion and threohydrobupropion metabolites are similar to that of the hydroxybupropion metabolite. However, their elimination half-lives are longer, 33(±10) and 37 (±13) hours, respectively, and steady-state AUCs are 1.5 and 7 times that of bupropion, respectively. •Absorption (Drug B): No absorption available •Volume of distribution (Drug A): No volume of distribution available •Volume of distribution (Drug B): No volume of distribution available •Protein binding (Drug A): In vitro tests show that bupropion is 84% bound to human plasma proteins at concentrations up to 200 mcg per mL. The extent of protein binding of the hydroxybupropion metabolite is similar to that for bupropion, whereas the extent of protein binding of the threohydrobupropion metabolite is about half that seen with bupropion. •Protein binding (Drug B): 94.2 +/- 2.1% (binds to serum protein, mainly albumin) •Metabolism (Drug A): Bupropion is extensively metabolized in humans. Three metabolites are active: hydroxybupropion, which is formed via hydroxylation of the tert-butyl group of bupropion, and the amino-alcohol isomers, threohydrobupropion and erythrohydrobupropion, which are formed via reduction of the carbonyl group. In vitro findings suggest that CYP2B6 is the principal isoenzyme involved in the formation of hydroxybupropion, while cytochrome P450 enzymes are not involved in the formation of threohydrobupropion. Hydroxybupropion has been shown to have the same affinity as bupropion for the norepinephrine transporter (NET) but approximately 50% of its antidepressant activity despite reaching concentrations of ~10-fold higher than that of the parent drug. Oxidation of the bupropion side chain results in the formation of a glycine conjugate of meta-chlorobenzoic acid, which is then excreted as the major urinary metabolite. The potency and toxicity of the metabolites relative to bupropion have not been fully characterized. However, it has been demonstrated in an antidepressant screening test in mice that hydroxybupropion is one-half as potent as bupropion, while threohydrobupropion and erythrohydrobupropion are 5-fold less potent than bupropion. This may be of clinical importance because the plasma concentrations of the metabolites are as high as or higher than those of bupropion. Bupropion and its metabolites exhibit linear kinetics following chronic administration of 300 to 450 mg per day. •Metabolism (Drug B): No metabolism available •Route of elimination (Drug A): Bupropion is extensively metabolized in humans. Oxidation of the bupropion side chain results in the formation of a glycine conjugate of metachlorobenzoic acid, which is then excreted as the major urinary metabolite. Following oral administration of 200 mg of 14C-bupropion in humans, 87% and 10% of the radioactive dose were recovered in the urine and feces, respectively. However, the fraction of the oral dose of bupropion excreted unchanged was only 0.5%, a finding consistent with the extensive metabolism of bupropion. •Route of elimination (Drug B): Oxacillin Sodium is rapidly excreted as unchanged drug in the urine by glomerular filtration and active tubular secretion. •Half-life (Drug A): 24 hours •Half-life (Drug B): 20 to 30 minutes •Clearance (Drug A): No clearance available •Clearance (Drug B): No clearance available •Toxicity (Drug A): Symptoms of overdose include seizures, hallucinations, loss of consciousness, tachycardia, and cardiac arrest. •Toxicity (Drug B): No toxicity available •Brand Names (Drug A): Aplenzin, Auvelity, Budeprion, Contrave, Forfivo, Wellbutrin, Zyban •Brand Names (Drug B): No brand names available •Synonyms (Drug A): No synonyms listed •Synonyms (Drug B): Ossacillina Oxacilina Oxacillin Oxacilline Oxacillinum Oxazocillin Oxazocilline •Summary (Drug A): Bupropion is a norepinephrine and dopamine reuptake inhibitor used in the treatment of major depressive disorder (MDD), seasonal affective disorder (SAD), and as an aid to smoking cessation. •Summary (Drug B): Oxacillin is a penicillin antibiotic used to treat a number of susceptible bacterial infections. Output: The renal excretion of drugs is the overall result of a combination of kidney processes that include glomerular filtration, passive diffusion, tubular secretion, and tubular reabsorption. Since two of these mechanisms - tubular secretion and reabsorption - are saturable processes , they are consequently susceptible to competition between multiple substrates excreted by the kidneys. If two or more medications that are mainly renally excreted are co-administered, they may compete for renal elimination; there is a large likelihood that one agent may "out-compete" or saturate the renal excretion mechanisms before the other concomitantly administered agent(s) are excreted. As a result, the elimination of these other concurrently administered agents may be inhibited or otherwise delayed, which could lead to increases in their serum concentrations and the risk, incidence, and/or severity of adverse effects associated with the exposure to such drugs. The severity of the interaction is minor.

Does Bupropion and Oxaliplatin interact?

•Drug A: Bupropion •Drug B: Oxaliplatin •Severity: MODERATE •Description: The excretion of Oxaliplatin can be decreased when combined with Bupropion. •Extended Description: Findings from in vitro studies showed that bupropion and its metabolites inhibit OCT2, suggesting that clinically relevant interaction through inhibition of OCT2 could occur at therapeutic bupropion doses. Co-administration of bupropion with OCT2 substrates may result in attenuated OCT2-mediated efflux of those drugs, thereby increasing drug serum concentrations. •Indication (Drug A): Bupropion is indicated for the treatment of major depressive disorder (MDD), seasonal affective disorder (SAD), and as an aid to smoking cessation. When used in combination with naltrexone as the marketed product ContraveⓇ, bupropion is indicated as an adjunct to a reduced-calorie diet and increased physical activity for chronic weight management in adults with an initial body mass index (BMI) of: 30 kg/m^2 or greater (obese) or 27 kg/m^2 or greater (overweight) in the presence of at least one weight-related comorbid condition (e.g., hypertension, type 2 diabetes mellitus, or dyslipidemia). Bupropion is also used off-label as a first-line treatment in patients with ADHD and comorbid bipolar disorder when used as an adjunct to mood stabilizers. •Indication (Drug B): Oxaliplatin, in combination with infusional fluorouracil and leucovorin, is indicated for the treatment of advanced colorectal cancer and adjuvant treatment of stage III colon cancer in patients who have undergone complete resection of the primary tumor. •Pharmacodynamics (Drug A): Bupropion is chemically unrelated to tricyclic, tetracyclic, selective serotonin re-uptake inhibitors, or other known antidepressant agents. Compared to classical tricyclic antidepressants, Bupropion is a relatively weak inhibitor of the neuronal uptake of norepinephrine and dopamine. In addition, Bupropion does not inhibit monoamine oxidase. Bupropion has been found to be essentially inactive at the serotonin transporter (SERT)(IC50 >10 000 nM), however both bupropion and its primary metabolite hydroxybupropion have been found to block the function of cation-selective serotonin type 3A receptors (5-HT3ARs). Bupropion produces dose-related central nervous system (CNS) stimulant effects in animals, as evidenced by increased locomotor activity, increased rates of responding in various schedule-controlled operant behaviour tasks, and, at high doses, induction of mild stereotyped behaviour. Due to these stimulant effects and selective activity at dopamine and norepinephrine receptors, bupropion has been identified as having an abuse potential. Bupropion has a similar structure to the controlled substance Cathinone, and has been identified as having mild amphetamine-like activity, particularly when inhaled or injected. Bupropion is also known to lower the seizure threshold, making any pre-existing seizure conditions a contraindication to its use. This risk is exacerbated when bupropion is combined with other drugs or substances that lower the seizure threshold, such as cocaine, or in clinical situations that would increase the risk of a seizure such as abrupt alcohol or benzodiazepine withdrawal. As norepinephrine has been shown to have anticonvulsant properties, bupropion's inhibitory effects on NET are thought to contribute to its pro-convulsant activity. Bupropion has been shown to increase blood pressure and pose a risk for exacerbation of unmanaged or pre-existing hypertension, however, clinical trials of bupropion in smokers with CVD have not identified an increased incidence of CV events including stroke or heart attack. In clinical trials, the mean increase in systolic blood pressure associated with the use of bupropion was found to be 1.3 mmHg. •Pharmacodynamics (Drug B): In vivo studies have shown antitumor activities of oxaliplatin against colon carcinoma. In combination with fluorouracil, oxaliplatin exhibits in vitro and in vivo antiproliferative activity greater than either compound alone in several tumor models (HT29 [colon], GR [mammary], and L1210 [leukemia]). •Mechanism of action (Drug A): Bupropion is a norepinephrine/dopamine-reuptake inhibitor (NDRI) that exerts its pharmacological effects by weakly inhibiting the enzymes involved in the uptake of the neurotransmitters norepinephrine and dopamine from the synaptic cleft, therefore prolonging their duration of action within the neuronal synapse and the downstream effects of these neurotransmitters. More specifically, bupropion binds to the norepinephrine transporter (NET) and the dopamine transporter (DAT). Bupropion was originally classified as an "atypical" antidepressant because it does not exert the same effects as the classical antidepressants such as Monoamine Oxidase Inhibitors (MAOIs), Tricyclic Antidepressants (TCAs), or Selective Serotonin Reuptake Inhibitors (SSRIs). While it has comparable effectiveness to typical first-line options for the treatment of depression such as SSRIs, bupropion is a unique option for the treatment of MDD as it lacks any clinically relevant serotonergic effects, typical of other mood medications, or any effects on histamine or adrenaline receptors. Lack of activity at these receptors results in a more tolerable side effect profile; bupropion is less likely to cause sexual side effects, sedation, or weight gain as compared to SSRIs or TCAs, for example. When used as an aid to smoking cessation, bupropion is thought to confer its anti-craving and anti-withdrawal effects by inhibiting dopamine reuptake, which is thought to be involved in the reward pathways associated with nicotine, and through the antagonism of the nicotinic acetylcholinergic receptor (AChR), thereby blunting the effects of nicotine. Furthermore, the stimulatory effects produced by bupropion in the central nervous system are similar to nicotine's effects, making low doses of bupropion a suitable option as a nicotine substitute. When used in combination with naltrexone in the marketed product ContraveⓇ for chronic weight management, the two components are thought to have effects on areas of the brain involved in the regulation of food intake. This includes the hypothalamus, which is involved in appetite regulation, and the mesolimbic dopamine circuit, which is involved in reward pathways. Studies have shown that the combined activity of bupropion and naltrexone increase the firing rate of hypothalamic pro-opiomelanocortin (POMC) neurons and blockade of opioid receptor-mediated POMC auto-inhibition, which are associated with a reduction in food intake and increased energy expenditure. This combination was also found to reduce food intake when injected directly into the ventral tegmental area of the mesolimbic circuit in mice, which is an area associated with the regulation of reward pathways. •Mechanism of action (Drug B): Oxaliplatin undergoes nonenzymatic conversion in physiologic solutions to active derivatives via displacement of the labile oxalate ligand. Several transient reactive species are formed, including monoaquo and diaquo DACH platinum, which covalently bind with macromolecules. Both inter and intrastrand Pt-DNA crosslinks are formed. Crosslinks are formed between the N7 positions of two adjacent guanines (GG), adjacent adenine-guanines (AG), and guanines separated by an intervening nucleotide (GNG). These crosslinks inhibit DNA replication and transcription. Cytotoxicity is cell-cycle nonspecific. •Absorption (Drug A): Bupropion is currently available in 3 distinct, but bioequivalent formulations: immediate release (IR), sustained-release (SR), and extended-release (XL). Immediate Release Formulation In humans, following oral administration of bupropion hydrochloride tablets, peak plasma bupropion concentrations are usually achieved within 2 hours. IR formulations provide a short duration of action and are therefore generally dosed three times per day. Sustained Release Formulation In humans, following oral administration of bupropion hydrochloride sustained-release tablets (SR), peak plasma concentration (Cmax) of bupropion is usually achieved within 3 hours. SR formulations provide a 12-hour extended release of medication and are therefore generally dosed twice per day. Extended Release Formulation Following single oral administration of bupropion hydrochloride extended-release tablets (XL) to healthy volunteers, the median time to peak plasma concentrations for bupropion was approximately 5 hours. The presence of food did not affect the peak concentration or area under the curve of bupropion. XL formulations provide a 24-hour extended release of medication and are therefore generally dosed once per day/ In a trial comparing chronic dosing with bupropion hydrochloride extended-release tablets (SR) 150 mg twice daily to bupropion immediate-release formulation 100 mg 3 times daily, the steady state Cmax for bupropion after bupropion hydrochloride sustained-release tablets (SR) administration was approximately 85% of those achieved after bupropion immediate-release formulation administration. Exposure (AUC) to bupropion was equivalent for both formulations. Bioequivalence was also demonstrated for all three major active metabolites (i.e., hydroxybupropion, threohydrobupropion and erythrohydrobupropion) for both Cmax and AUC. Thus, at steady state, bupropion hydrochloride sustained-release tablets (SR) given twice daily, and the immediate-release formulation of bupropion given 3 times daily, are essentially bioequivalent for both bupropion and the 3 quantitatively important metabolites. Furthermore, in a study comparing 14-day dosing with bupropion hydrochloride extended-release tablets (XL), 300 mg once-daily to the immediate-release formulation of bupropion at 100 mg 3 times daily, equivalence was demonstrated for peak plasma concentration and area under the curve for bupropion and the three metabolites (hydroxybupropion, threohydrobupropion, and erythrohydrobupropion). Additionally, in a study comparing 14-day dosing with bupropion hydrochloride extended-release tablets (XL) 300 mg once daily to the sustained-release formulation of bupropion at 150 mg 2 times daily, equivalence was demonstrated for peak plasma concentration and area under the curve for bupropion and the three metabolites. Bupropion hydrochloride extended-release tablets (SR) can be taken with or without food. Bupropion Cmax and AUC were increased by 11% to 35% and 16% to 19%, respectively, when bupropion hydrochloride extended-release tablets (SR) was administered with food to healthy volunteers in three trials. The food effect is not considered clinically significant. Following a single-dose administration of bupropion hydrochloride extended-release tablets (SR) in humans, Cmax of bupropion's metabolite hydroxybupropion occurs approximately 6 hours post-dose and is approximately 10 times the peak level of the parent drug at steady state. The elimination half-life of hydroxybupropion is approximately 20 (±5) hours and its AUC at steady state is about 17 times that of bupropion. The times to peak concentrations for the erythrohydrobupropion and threohydrobupropion metabolites are similar to that of the hydroxybupropion metabolite. However, their elimination half-lives are longer, 33(±10) and 37 (±13) hours, respectively, and steady-state AUCs are 1.5 and 7 times that of bupropion, respectively. •Absorption (Drug B): The reactive oxaliplatin derivatives are present as a fraction of the unbound platinum in plasma ultrafiltrate. After a single 2-hour intravenous infusion of oxaliplatin at a dose of 85 mg/m, pharmacokinetic parameters expressed as ultrafiltrable platinum was C max of 0.814 mcg/mL. Interpatient and intrapatient variability in ultrafiltrable platinum exposure (AUC 0-48hr ) assessed over 3 cycles was 23% and 6%, respectively. •Volume of distribution (Drug A): No volume of distribution available •Volume of distribution (Drug B): After a single 2-hour intravenous infusion of oxaliplatin at a dose of 85 mg/m, the volume of distribution is 440 L.At the end of a 2-hour infusion, approximately 15% of the administered platinum is present in the systemic circulation. The remaining 85% is rapidly distributed into tissues or eliminated in the urine. •Protein binding (Drug A): In vitro tests show that bupropion is 84% bound to human plasma proteins at concentrations up to 200 mcg per mL. The extent of protein binding of the hydroxybupropion metabolite is similar to that for bupropion, whereas the extent of protein binding of the threohydrobupropion metabolite is about half that seen with bupropion. •Protein binding (Drug B): In patients, plasma protein binding of platinum is irreversible and is greater than 90%. The main binding proteins are albumin and gamma-globulins. Platinum also binds irreversibly and accumulates (approximately 2-fold) in erythrocytes, where it appears to have no relevant activity. No platinum accumulation was observed in plasma ultrafiltrate following 85 mg/m every two weeks. •Metabolism (Drug A): Bupropion is extensively metabolized in humans. Three metabolites are active: hydroxybupropion, which is formed via hydroxylation of the tert-butyl group of bupropion, and the amino-alcohol isomers, threohydrobupropion and erythrohydrobupropion, which are formed via reduction of the carbonyl group. In vitro findings suggest that CYP2B6 is the principal isoenzyme involved in the formation of hydroxybupropion, while cytochrome P450 enzymes are not involved in the formation of threohydrobupropion. Hydroxybupropion has been shown to have the same affinity as bupropion for the norepinephrine transporter (NET) but approximately 50% of its antidepressant activity despite reaching concentrations of ~10-fold higher than that of the parent drug. Oxidation of the bupropion side chain results in the formation of a glycine conjugate of meta-chlorobenzoic acid, which is then excreted as the major urinary metabolite. The potency and toxicity of the metabolites relative to bupropion have not been fully characterized. However, it has been demonstrated in an antidepressant screening test in mice that hydroxybupropion is one-half as potent as bupropion, while threohydrobupropion and erythrohydrobupropion are 5-fold less potent than bupropion. This may be of clinical importance because the plasma concentrations of the metabolites are as high as or higher than those of bupropion. Bupropion and its metabolites exhibit linear kinetics following chronic administration of 300 to 450 mg per day. •Metabolism (Drug B): Oxaliplatin undergoes rapid and extensive nonenzymatic biotransformation. There is no evidence of cytochrome P450-mediated metabolism in vitro. Up to 17 platinum-containing derivatives have been observed in plasma ultrafiltrate samples from patients, including several cytotoxic species (monochloro DACH platinum, dichloro DACH platinum, and monoaquo and diaquo DACH platinum) and a number of noncytotoxic, conjugated species. •Route of elimination (Drug A): Bupropion is extensively metabolized in humans. Oxidation of the bupropion side chain results in the formation of a glycine conjugate of metachlorobenzoic acid, which is then excreted as the major urinary metabolite. Following oral administration of 200 mg of 14C-bupropion in humans, 87% and 10% of the radioactive dose were recovered in the urine and feces, respectively. However, the fraction of the oral dose of bupropion excreted unchanged was only 0.5%, a finding consistent with the extensive metabolism of bupropion. •Route of elimination (Drug B): The major route of platinum elimination is renal excretion. At five days after a single 2-hour infusion of ELOXATIN, urinary elimination accounted for about 54% of the platinum eliminated, with fecal excretion accounting for only about 2%. •Half-life (Drug A): 24 hours •Half-life (Drug B): The decline of ultrafilterable platinum levels following oxaliplatin administration is triphasic with two distribution phases: t1/2α; 0.43 hours and t1/2β; 16.8 hours. This is followed by a long terminal elimination phase that lasts 391 hours (t1/2γ). •Clearance (Drug A): No clearance available •Clearance (Drug B): Platinum was cleared from plasma at a rate (10-17 L/h) that was similar to or exceeded the average human glomerular filtration rate (GFR; 7.5 L/h). The renal clearance of ultrafiltrable platinum is significantly correlated with GFR. •Toxicity (Drug A): Symptoms of overdose include seizures, hallucinations, loss of consciousness, tachycardia, and cardiac arrest. •Toxicity (Drug B): The maximum dose of oxaliplatin that has been administered in a single infusion is 825 mg. Several cases of overdoses have been reported with oxaliplatin. Adverse reactions observed following an overdosage were grade 4 thrombocytopenia (less than 25,000/mm3) without bleeding, anemia, sensory neuropathy (including paresthesia, dysesthesia, laryngospasm, and facial muscle spasms), gastrointestinal disorders (including nausea, vomiting, stomatitis, flatulence, abdomen enlarged and grade 4 intestinal obstruction), grade 4 dehydration, dyspnea, wheezing, chest pain, respiratory failure, severe bradycardia, and death. Closely monitor patients suspected of receiving an overdose, including for the adverse reactions described above, and administer appropriate supportive treatment. Based on its direct interaction with DNA, ELOXATIN can cause fetal harm when administered to a pregnant woman. The available human data do not establish the presence or absence of major birth defects or miscarriages related to the use of oxaliplatin. Reproductive toxicity studies demonstrated adverse effects on embryo-fetal development in rats at maternal doses that were below the recommended human dose based on body surface area. Advise a pregnant woman of the potential risk to a fetus. In the adjuvant treatment trial, 400 patients who received oxaliplatin with fluorouracil/leucovorin were greater than or equal to 65 years. The effect of oxaliplatin in patients greater than or equal to 65 years was not conclusive. Patients greater than or equal to 65 years receiving ELOXATIN experienced more diarrhea and grade 3-4 neutropenia (45% vs 39%) compared to patients less than 65 years. The AUC of unbound platinum in plasma ultrafiltrate was increased in patients with renal impairment. No dose reduction is recommended for patients with mild (creatinine clearance 50 to 79 mL/min) or moderate (creatinine clearance 30 to 49 mL/min) renal impairment, calculated by Cockcroft-Gault equation. Reduce the dose of oxaliplatin in patients with severe renal impairment (creatinine clearance less than 30 mL/min). Long-term animal studies have not been performed to evaluate the carcinogenic potential of oxaliplatin. Oxaliplatin was not mutagenic to bacteria (Ames test) but was mutagenic to mammalian cells in vitro (L5178Y mouse lymphoma assay). Oxaliplatin was clastogenic both in vitro (chromosome aberration in human lymphocytes) and in vivo (mouse bone marrow micronucleus assay). In a fertility study, male rats were given oxaliplatin at 0, 0.5, 1, or 2 mg/kg/day for five days every 21 days for a total of three cycles prior to mating with females that received two cycles of oxaliplatin on the same schedule. A dose of 2 mg/kg/day (less than one-seventh the recommended human dose on a body surface area basis) did not affect the pregnancy rate but resulted in 97% postimplantation loss (increased early resorptions, decreased live fetuses, decreased live births), and delayed growth (decreased fetal weight). Testicular damage, characterized by degeneration, hypoplasia, and atrophy, was observed in dogs administered oxaliplatin at 0.75 mg/kg/day (approximately one-sixth of the recommended human dose on a body surface area basis) × 5 days every 28 days for three cycles. A no-effect level was not identified. •Brand Names (Drug A): Aplenzin, Auvelity, Budeprion, Contrave, Forfivo, Wellbutrin, Zyban •Brand Names (Drug B): No brand names available •Synonyms (Drug A): No synonyms listed •Synonyms (Drug B): No synonyms listed •Summary (Drug A): Bupropion is a norepinephrine and dopamine reuptake inhibitor used in the treatment of major depressive disorder (MDD), seasonal affective disorder (SAD), and as an aid to smoking cessation. •Summary (Drug B): Oxaliplatin is a platinum based chemotherapy agent used to treat carcinoma of the colon or rectum or stage III colon cancer.

Findings from in vitro studies showed that bupropion and its metabolites inhibit OCT2, suggesting that clinically relevant interaction through inhibition of OCT2 could occur at therapeutic bupropion doses. Co-administration of bupropion with OCT2 substrates may result in attenuated OCT2-mediated efflux of those drugs, thereby increasing drug serum concentrations. The severity of the interaction is moderate.

Question: Does Bupropion and Oxaliplatin interact? Information: •Drug A: Bupropion •Drug B: Oxaliplatin •Severity: MODERATE •Description: The excretion of Oxaliplatin can be decreased when combined with Bupropion. •Extended Description: Findings from in vitro studies showed that bupropion and its metabolites inhibit OCT2, suggesting that clinically relevant interaction through inhibition of OCT2 could occur at therapeutic bupropion doses. Co-administration of bupropion with OCT2 substrates may result in attenuated OCT2-mediated efflux of those drugs, thereby increasing drug serum concentrations. •Indication (Drug A): Bupropion is indicated for the treatment of major depressive disorder (MDD), seasonal affective disorder (SAD), and as an aid to smoking cessation. When used in combination with naltrexone as the marketed product ContraveⓇ, bupropion is indicated as an adjunct to a reduced-calorie diet and increased physical activity for chronic weight management in adults with an initial body mass index (BMI) of: 30 kg/m^2 or greater (obese) or 27 kg/m^2 or greater (overweight) in the presence of at least one weight-related comorbid condition (e.g., hypertension, type 2 diabetes mellitus, or dyslipidemia). Bupropion is also used off-label as a first-line treatment in patients with ADHD and comorbid bipolar disorder when used as an adjunct to mood stabilizers. •Indication (Drug B): Oxaliplatin, in combination with infusional fluorouracil and leucovorin, is indicated for the treatment of advanced colorectal cancer and adjuvant treatment of stage III colon cancer in patients who have undergone complete resection of the primary tumor. •Pharmacodynamics (Drug A): Bupropion is chemically unrelated to tricyclic, tetracyclic, selective serotonin re-uptake inhibitors, or other known antidepressant agents. Compared to classical tricyclic antidepressants, Bupropion is a relatively weak inhibitor of the neuronal uptake of norepinephrine and dopamine. In addition, Bupropion does not inhibit monoamine oxidase. Bupropion has been found to be essentially inactive at the serotonin transporter (SERT)(IC50 >10 000 nM), however both bupropion and its primary metabolite hydroxybupropion have been found to block the function of cation-selective serotonin type 3A receptors (5-HT3ARs). Bupropion produces dose-related central nervous system (CNS) stimulant effects in animals, as evidenced by increased locomotor activity, increased rates of responding in various schedule-controlled operant behaviour tasks, and, at high doses, induction of mild stereotyped behaviour. Due to these stimulant effects and selective activity at dopamine and norepinephrine receptors, bupropion has been identified as having an abuse potential. Bupropion has a similar structure to the controlled substance Cathinone, and has been identified as having mild amphetamine-like activity, particularly when inhaled or injected. Bupropion is also known to lower the seizure threshold, making any pre-existing seizure conditions a contraindication to its use. This risk is exacerbated when bupropion is combined with other drugs or substances that lower the seizure threshold, such as cocaine, or in clinical situations that would increase the risk of a seizure such as abrupt alcohol or benzodiazepine withdrawal. As norepinephrine has been shown to have anticonvulsant properties, bupropion's inhibitory effects on NET are thought to contribute to its pro-convulsant activity. Bupropion has been shown to increase blood pressure and pose a risk for exacerbation of unmanaged or pre-existing hypertension, however, clinical trials of bupropion in smokers with CVD have not identified an increased incidence of CV events including stroke or heart attack. In clinical trials, the mean increase in systolic blood pressure associated with the use of bupropion was found to be 1.3 mmHg. •Pharmacodynamics (Drug B): In vivo studies have shown antitumor activities of oxaliplatin against colon carcinoma. In combination with fluorouracil, oxaliplatin exhibits in vitro and in vivo antiproliferative activity greater than either compound alone in several tumor models (HT29 [colon], GR [mammary], and L1210 [leukemia]). •Mechanism of action (Drug A): Bupropion is a norepinephrine/dopamine-reuptake inhibitor (NDRI) that exerts its pharmacological effects by weakly inhibiting the enzymes involved in the uptake of the neurotransmitters norepinephrine and dopamine from the synaptic cleft, therefore prolonging their duration of action within the neuronal synapse and the downstream effects of these neurotransmitters. More specifically, bupropion binds to the norepinephrine transporter (NET) and the dopamine transporter (DAT). Bupropion was originally classified as an "atypical" antidepressant because it does not exert the same effects as the classical antidepressants such as Monoamine Oxidase Inhibitors (MAOIs), Tricyclic Antidepressants (TCAs), or Selective Serotonin Reuptake Inhibitors (SSRIs). While it has comparable effectiveness to typical first-line options for the treatment of depression such as SSRIs, bupropion is a unique option for the treatment of MDD as it lacks any clinically relevant serotonergic effects, typical of other mood medications, or any effects on histamine or adrenaline receptors. Lack of activity at these receptors results in a more tolerable side effect profile; bupropion is less likely to cause sexual side effects, sedation, or weight gain as compared to SSRIs or TCAs, for example. When used as an aid to smoking cessation, bupropion is thought to confer its anti-craving and anti-withdrawal effects by inhibiting dopamine reuptake, which is thought to be involved in the reward pathways associated with nicotine, and through the antagonism of the nicotinic acetylcholinergic receptor (AChR), thereby blunting the effects of nicotine. Furthermore, the stimulatory effects produced by bupropion in the central nervous system are similar to nicotine's effects, making low doses of bupropion a suitable option as a nicotine substitute. When used in combination with naltrexone in the marketed product ContraveⓇ for chronic weight management, the two components are thought to have effects on areas of the brain involved in the regulation of food intake. This includes the hypothalamus, which is involved in appetite regulation, and the mesolimbic dopamine circuit, which is involved in reward pathways. Studies have shown that the combined activity of bupropion and naltrexone increase the firing rate of hypothalamic pro-opiomelanocortin (POMC) neurons and blockade of opioid receptor-mediated POMC auto-inhibition, which are associated with a reduction in food intake and increased energy expenditure. This combination was also found to reduce food intake when injected directly into the ventral tegmental area of the mesolimbic circuit in mice, which is an area associated with the regulation of reward pathways. •Mechanism of action (Drug B): Oxaliplatin undergoes nonenzymatic conversion in physiologic solutions to active derivatives via displacement of the labile oxalate ligand. Several transient reactive species are formed, including monoaquo and diaquo DACH platinum, which covalently bind with macromolecules. Both inter and intrastrand Pt-DNA crosslinks are formed. Crosslinks are formed between the N7 positions of two adjacent guanines (GG), adjacent adenine-guanines (AG), and guanines separated by an intervening nucleotide (GNG). These crosslinks inhibit DNA replication and transcription. Cytotoxicity is cell-cycle nonspecific. •Absorption (Drug A): Bupropion is currently available in 3 distinct, but bioequivalent formulations: immediate release (IR), sustained-release (SR), and extended-release (XL). Immediate Release Formulation In humans, following oral administration of bupropion hydrochloride tablets, peak plasma bupropion concentrations are usually achieved within 2 hours. IR formulations provide a short duration of action and are therefore generally dosed three times per day. Sustained Release Formulation In humans, following oral administration of bupropion hydrochloride sustained-release tablets (SR), peak plasma concentration (Cmax) of bupropion is usually achieved within 3 hours. SR formulations provide a 12-hour extended release of medication and are therefore generally dosed twice per day. Extended Release Formulation Following single oral administration of bupropion hydrochloride extended-release tablets (XL) to healthy volunteers, the median time to peak plasma concentrations for bupropion was approximately 5 hours. The presence of food did not affect the peak concentration or area under the curve of bupropion. XL formulations provide a 24-hour extended release of medication and are therefore generally dosed once per day/ In a trial comparing chronic dosing with bupropion hydrochloride extended-release tablets (SR) 150 mg twice daily to bupropion immediate-release formulation 100 mg 3 times daily, the steady state Cmax for bupropion after bupropion hydrochloride sustained-release tablets (SR) administration was approximately 85% of those achieved after bupropion immediate-release formulation administration. Exposure (AUC) to bupropion was equivalent for both formulations. Bioequivalence was also demonstrated for all three major active metabolites (i.e., hydroxybupropion, threohydrobupropion and erythrohydrobupropion) for both Cmax and AUC. Thus, at steady state, bupropion hydrochloride sustained-release tablets (SR) given twice daily, and the immediate-release formulation of bupropion given 3 times daily, are essentially bioequivalent for both bupropion and the 3 quantitatively important metabolites. Furthermore, in a study comparing 14-day dosing with bupropion hydrochloride extended-release tablets (XL), 300 mg once-daily to the immediate-release formulation of bupropion at 100 mg 3 times daily, equivalence was demonstrated for peak plasma concentration and area under the curve for bupropion and the three metabolites (hydroxybupropion, threohydrobupropion, and erythrohydrobupropion). Additionally, in a study comparing 14-day dosing with bupropion hydrochloride extended-release tablets (XL) 300 mg once daily to the sustained-release formulation of bupropion at 150 mg 2 times daily, equivalence was demonstrated for peak plasma concentration and area under the curve for bupropion and the three metabolites. Bupropion hydrochloride extended-release tablets (SR) can be taken with or without food. Bupropion Cmax and AUC were increased by 11% to 35% and 16% to 19%, respectively, when bupropion hydrochloride extended-release tablets (SR) was administered with food to healthy volunteers in three trials. The food effect is not considered clinically significant. Following a single-dose administration of bupropion hydrochloride extended-release tablets (SR) in humans, Cmax of bupropion's metabolite hydroxybupropion occurs approximately 6 hours post-dose and is approximately 10 times the peak level of the parent drug at steady state. The elimination half-life of hydroxybupropion is approximately 20 (±5) hours and its AUC at steady state is about 17 times that of bupropion. The times to peak concentrations for the erythrohydrobupropion and threohydrobupropion metabolites are similar to that of the hydroxybupropion metabolite. However, their elimination half-lives are longer, 33(±10) and 37 (±13) hours, respectively, and steady-state AUCs are 1.5 and 7 times that of bupropion, respectively. •Absorption (Drug B): The reactive oxaliplatin derivatives are present as a fraction of the unbound platinum in plasma ultrafiltrate. After a single 2-hour intravenous infusion of oxaliplatin at a dose of 85 mg/m, pharmacokinetic parameters expressed as ultrafiltrable platinum was C max of 0.814 mcg/mL. Interpatient and intrapatient variability in ultrafiltrable platinum exposure (AUC 0-48hr ) assessed over 3 cycles was 23% and 6%, respectively. •Volume of distribution (Drug A): No volume of distribution available •Volume of distribution (Drug B): After a single 2-hour intravenous infusion of oxaliplatin at a dose of 85 mg/m, the volume of distribution is 440 L.At the end of a 2-hour infusion, approximately 15% of the administered platinum is present in the systemic circulation. The remaining 85% is rapidly distributed into tissues or eliminated in the urine. •Protein binding (Drug A): In vitro tests show that bupropion is 84% bound to human plasma proteins at concentrations up to 200 mcg per mL. The extent of protein binding of the hydroxybupropion metabolite is similar to that for bupropion, whereas the extent of protein binding of the threohydrobupropion metabolite is about half that seen with bupropion. •Protein binding (Drug B): In patients, plasma protein binding of platinum is irreversible and is greater than 90%. The main binding proteins are albumin and gamma-globulins. Platinum also binds irreversibly and accumulates (approximately 2-fold) in erythrocytes, where it appears to have no relevant activity. No platinum accumulation was observed in plasma ultrafiltrate following 85 mg/m every two weeks. •Metabolism (Drug A): Bupropion is extensively metabolized in humans. Three metabolites are active: hydroxybupropion, which is formed via hydroxylation of the tert-butyl group of bupropion, and the amino-alcohol isomers, threohydrobupropion and erythrohydrobupropion, which are formed via reduction of the carbonyl group. In vitro findings suggest that CYP2B6 is the principal isoenzyme involved in the formation of hydroxybupropion, while cytochrome P450 enzymes are not involved in the formation of threohydrobupropion. Hydroxybupropion has been shown to have the same affinity as bupropion for the norepinephrine transporter (NET) but approximately 50% of its antidepressant activity despite reaching concentrations of ~10-fold higher than that of the parent drug. Oxidation of the bupropion side chain results in the formation of a glycine conjugate of meta-chlorobenzoic acid, which is then excreted as the major urinary metabolite. The potency and toxicity of the metabolites relative to bupropion have not been fully characterized. However, it has been demonstrated in an antidepressant screening test in mice that hydroxybupropion is one-half as potent as bupropion, while threohydrobupropion and erythrohydrobupropion are 5-fold less potent than bupropion. This may be of clinical importance because the plasma concentrations of the metabolites are as high as or higher than those of bupropion. Bupropion and its metabolites exhibit linear kinetics following chronic administration of 300 to 450 mg per day. •Metabolism (Drug B): Oxaliplatin undergoes rapid and extensive nonenzymatic biotransformation. There is no evidence of cytochrome P450-mediated metabolism in vitro. Up to 17 platinum-containing derivatives have been observed in plasma ultrafiltrate samples from patients, including several cytotoxic species (monochloro DACH platinum, dichloro DACH platinum, and monoaquo and diaquo DACH platinum) and a number of noncytotoxic, conjugated species. •Route of elimination (Drug A): Bupropion is extensively metabolized in humans. Oxidation of the bupropion side chain results in the formation of a glycine conjugate of metachlorobenzoic acid, which is then excreted as the major urinary metabolite. Following oral administration of 200 mg of 14C-bupropion in humans, 87% and 10% of the radioactive dose were recovered in the urine and feces, respectively. However, the fraction of the oral dose of bupropion excreted unchanged was only 0.5%, a finding consistent with the extensive metabolism of bupropion. •Route of elimination (Drug B): The major route of platinum elimination is renal excretion. At five days after a single 2-hour infusion of ELOXATIN, urinary elimination accounted for about 54% of the platinum eliminated, with fecal excretion accounting for only about 2%. •Half-life (Drug A): 24 hours •Half-life (Drug B): The decline of ultrafilterable platinum levels following oxaliplatin administration is triphasic with two distribution phases: t1/2α; 0.43 hours and t1/2β; 16.8 hours. This is followed by a long terminal elimination phase that lasts 391 hours (t1/2γ). •Clearance (Drug A): No clearance available •Clearance (Drug B): Platinum was cleared from plasma at a rate (10-17 L/h) that was similar to or exceeded the average human glomerular filtration rate (GFR; 7.5 L/h). The renal clearance of ultrafiltrable platinum is significantly correlated with GFR. •Toxicity (Drug A): Symptoms of overdose include seizures, hallucinations, loss of consciousness, tachycardia, and cardiac arrest. •Toxicity (Drug B): The maximum dose of oxaliplatin that has been administered in a single infusion is 825 mg. Several cases of overdoses have been reported with oxaliplatin. Adverse reactions observed following an overdosage were grade 4 thrombocytopenia (less than 25,000/mm3) without bleeding, anemia, sensory neuropathy (including paresthesia, dysesthesia, laryngospasm, and facial muscle spasms), gastrointestinal disorders (including nausea, vomiting, stomatitis, flatulence, abdomen enlarged and grade 4 intestinal obstruction), grade 4 dehydration, dyspnea, wheezing, chest pain, respiratory failure, severe bradycardia, and death. Closely monitor patients suspected of receiving an overdose, including for the adverse reactions described above, and administer appropriate supportive treatment. Based on its direct interaction with DNA, ELOXATIN can cause fetal harm when administered to a pregnant woman. The available human data do not establish the presence or absence of major birth defects or miscarriages related to the use of oxaliplatin. Reproductive toxicity studies demonstrated adverse effects on embryo-fetal development in rats at maternal doses that were below the recommended human dose based on body surface area. Advise a pregnant woman of the potential risk to a fetus. In the adjuvant treatment trial, 400 patients who received oxaliplatin with fluorouracil/leucovorin were greater than or equal to 65 years. The effect of oxaliplatin in patients greater than or equal to 65 years was not conclusive. Patients greater than or equal to 65 years receiving ELOXATIN experienced more diarrhea and grade 3-4 neutropenia (45% vs 39%) compared to patients less than 65 years. The AUC of unbound platinum in plasma ultrafiltrate was increased in patients with renal impairment. No dose reduction is recommended for patients with mild (creatinine clearance 50 to 79 mL/min) or moderate (creatinine clearance 30 to 49 mL/min) renal impairment, calculated by Cockcroft-Gault equation. Reduce the dose of oxaliplatin in patients with severe renal impairment (creatinine clearance less than 30 mL/min). Long-term animal studies have not been performed to evaluate the carcinogenic potential of oxaliplatin. Oxaliplatin was not mutagenic to bacteria (Ames test) but was mutagenic to mammalian cells in vitro (L5178Y mouse lymphoma assay). Oxaliplatin was clastogenic both in vitro (chromosome aberration in human lymphocytes) and in vivo (mouse bone marrow micronucleus assay). In a fertility study, male rats were given oxaliplatin at 0, 0.5, 1, or 2 mg/kg/day for five days every 21 days for a total of three cycles prior to mating with females that received two cycles of oxaliplatin on the same schedule. A dose of 2 mg/kg/day (less than one-seventh the recommended human dose on a body surface area basis) did not affect the pregnancy rate but resulted in 97% postimplantation loss (increased early resorptions, decreased live fetuses, decreased live births), and delayed growth (decreased fetal weight). Testicular damage, characterized by degeneration, hypoplasia, and atrophy, was observed in dogs administered oxaliplatin at 0.75 mg/kg/day (approximately one-sixth of the recommended human dose on a body surface area basis) × 5 days every 28 days for three cycles. A no-effect level was not identified. •Brand Names (Drug A): Aplenzin, Auvelity, Budeprion, Contrave, Forfivo, Wellbutrin, Zyban •Brand Names (Drug B): No brand names available •Synonyms (Drug A): No synonyms listed •Synonyms (Drug B): No synonyms listed •Summary (Drug A): Bupropion is a norepinephrine and dopamine reuptake inhibitor used in the treatment of major depressive disorder (MDD), seasonal affective disorder (SAD), and as an aid to smoking cessation. •Summary (Drug B): Oxaliplatin is a platinum based chemotherapy agent used to treat carcinoma of the colon or rectum or stage III colon cancer. Output: Findings from in vitro studies showed that bupropion and its metabolites inhibit OCT2, suggesting that clinically relevant interaction through inhibition of OCT2 could occur at therapeutic bupropion doses. Co-administration of bupropion with OCT2 substrates may result in attenuated OCT2-mediated efflux of those drugs, thereby increasing drug serum concentrations. The severity of the interaction is moderate.

Does Bupropion and Oxandrolone interact?

•Drug A: Bupropion •Drug B: Oxandrolone •Severity: MODERATE •Description: The metabolism of Bupropion can be decreased when combined with Oxandrolone. •Extended Description: The subject drug is known to be an inhibitor of CYP2C9 while the affected drug is reported to be metabolized by CYP2C9. Concomitant administration of these agents can cause an increase in the serum concentration of the affected drug due to decreased metabolism by CYP2C9, which may result in increased incidence and/or severity of adverse effects related to the affected drug. •Indication (Drug A): Bupropion is indicated for the treatment of major depressive disorder (MDD), seasonal affective disorder (SAD), and as an aid to smoking cessation. When used in combination with naltrexone as the marketed product ContraveⓇ, bupropion is indicated as an adjunct to a reduced-calorie diet and increased physical activity for chronic weight management in adults with an initial body mass index (BMI) of: 30 kg/m^2 or greater (obese) or 27 kg/m^2 or greater (overweight) in the presence of at least one weight-related comorbid condition (e.g., hypertension, type 2 diabetes mellitus, or dyslipidemia). Bupropion is also used off-label as a first-line treatment in patients with ADHD and comorbid bipolar disorder when used as an adjunct to mood stabilizers. •Indication (Drug B): Use to promote weight gain after weight loss following extensive surgery. •Pharmacodynamics (Drug A): Bupropion is chemically unrelated to tricyclic, tetracyclic, selective serotonin re-uptake inhibitors, or other known antidepressant agents. Compared to classical tricyclic antidepressants, Bupropion is a relatively weak inhibitor of the neuronal uptake of norepinephrine and dopamine. In addition, Bupropion does not inhibit monoamine oxidase. Bupropion has been found to be essentially inactive at the serotonin transporter (SERT)(IC50 >10 000 nM), however both bupropion and its primary metabolite hydroxybupropion have been found to block the function of cation-selective serotonin type 3A receptors (5-HT3ARs). Bupropion produces dose-related central nervous system (CNS) stimulant effects in animals, as evidenced by increased locomotor activity, increased rates of responding in various schedule-controlled operant behaviour tasks, and, at high doses, induction of mild stereotyped behaviour. Due to these stimulant effects and selective activity at dopamine and norepinephrine receptors, bupropion has been identified as having an abuse potential. Bupropion has a similar structure to the controlled substance Cathinone, and has been identified as having mild amphetamine-like activity, particularly when inhaled or injected. Bupropion is also known to lower the seizure threshold, making any pre-existing seizure conditions a contraindication to its use. This risk is exacerbated when bupropion is combined with other drugs or substances that lower the seizure threshold, such as cocaine, or in clinical situations that would increase the risk of a seizure such as abrupt alcohol or benzodiazepine withdrawal. As norepinephrine has been shown to have anticonvulsant properties, bupropion's inhibitory effects on NET are thought to contribute to its pro-convulsant activity. Bupropion has been shown to increase blood pressure and pose a risk for exacerbation of unmanaged or pre-existing hypertension, however, clinical trials of bupropion in smokers with CVD have not identified an increased incidence of CV events including stroke or heart attack. In clinical trials, the mean increase in systolic blood pressure associated with the use of bupropion was found to be 1.3 mmHg. •Pharmacodynamics (Drug B): Oxandrolone is an anabolic steroids indicated as adjunctive therapy to promote weight gain after weight loss following extensive surgery, chronic infections, or severe trauma, and in some patients who without definite pathophysiologic reasons fail to gain or to maintain normal weight, to offset the protein catabolism associated with prolonged administration of corticosteroids, and for the relief of the bone pain frequently accompanying osteoporosis. Anabolic steroids are synthetic derivatives of testosterone. •Mechanism of action (Drug A): Bupropion is a norepinephrine/dopamine-reuptake inhibitor (NDRI) that exerts its pharmacological effects by weakly inhibiting the enzymes involved in the uptake of the neurotransmitters norepinephrine and dopamine from the synaptic cleft, therefore prolonging their duration of action within the neuronal synapse and the downstream effects of these neurotransmitters. More specifically, bupropion binds to the norepinephrine transporter (NET) and the dopamine transporter (DAT). Bupropion was originally classified as an "atypical" antidepressant because it does not exert the same effects as the classical antidepressants such as Monoamine Oxidase Inhibitors (MAOIs), Tricyclic Antidepressants (TCAs), or Selective Serotonin Reuptake Inhibitors (SSRIs). While it has comparable effectiveness to typical first-line options for the treatment of depression such as SSRIs, bupropion is a unique option for the treatment of MDD as it lacks any clinically relevant serotonergic effects, typical of other mood medications, or any effects on histamine or adrenaline receptors. Lack of activity at these receptors results in a more tolerable side effect profile; bupropion is less likely to cause sexual side effects, sedation, or weight gain as compared to SSRIs or TCAs, for example. When used as an aid to smoking cessation, bupropion is thought to confer its anti-craving and anti-withdrawal effects by inhibiting dopamine reuptake, which is thought to be involved in the reward pathways associated with nicotine, and through the antagonism of the nicotinic acetylcholinergic receptor (AChR), thereby blunting the effects of nicotine. Furthermore, the stimulatory effects produced by bupropion in the central nervous system are similar to nicotine's effects, making low doses of bupropion a suitable option as a nicotine substitute. When used in combination with naltrexone in the marketed product ContraveⓇ for chronic weight management, the two components are thought to have effects on areas of the brain involved in the regulation of food intake. This includes the hypothalamus, which is involved in appetite regulation, and the mesolimbic dopamine circuit, which is involved in reward pathways. Studies have shown that the combined activity of bupropion and naltrexone increase the firing rate of hypothalamic pro-opiomelanocortin (POMC) neurons and blockade of opioid receptor-mediated POMC auto-inhibition, which are associated with a reduction in food intake and increased energy expenditure. This combination was also found to reduce food intake when injected directly into the ventral tegmental area of the mesolimbic circuit in mice, which is an area associated with the regulation of reward pathways. •Mechanism of action (Drug B): Oxandrolones interact with androgen receptors in target tissues. •Absorption (Drug A): Bupropion is currently available in 3 distinct, but bioequivalent formulations: immediate release (IR), sustained-release (SR), and extended-release (XL). Immediate Release Formulation In humans, following oral administration of bupropion hydrochloride tablets, peak plasma bupropion concentrations are usually achieved within 2 hours. IR formulations provide a short duration of action and are therefore generally dosed three times per day. Sustained Release Formulation In humans, following oral administration of bupropion hydrochloride sustained-release tablets (SR), peak plasma concentration (Cmax) of bupropion is usually achieved within 3 hours. SR formulations provide a 12-hour extended release of medication and are therefore generally dosed twice per day. Extended Release Formulation Following single oral administration of bupropion hydrochloride extended-release tablets (XL) to healthy volunteers, the median time to peak plasma concentrations for bupropion was approximately 5 hours. The presence of food did not affect the peak concentration or area under the curve of bupropion. XL formulations provide a 24-hour extended release of medication and are therefore generally dosed once per day/ In a trial comparing chronic dosing with bupropion hydrochloride extended-release tablets (SR) 150 mg twice daily to bupropion immediate-release formulation 100 mg 3 times daily, the steady state Cmax for bupropion after bupropion hydrochloride sustained-release tablets (SR) administration was approximately 85% of those achieved after bupropion immediate-release formulation administration. Exposure (AUC) to bupropion was equivalent for both formulations. Bioequivalence was also demonstrated for all three major active metabolites (i.e., hydroxybupropion, threohydrobupropion and erythrohydrobupropion) for both Cmax and AUC. Thus, at steady state, bupropion hydrochloride sustained-release tablets (SR) given twice daily, and the immediate-release formulation of bupropion given 3 times daily, are essentially bioequivalent for both bupropion and the 3 quantitatively important metabolites. Furthermore, in a study comparing 14-day dosing with bupropion hydrochloride extended-release tablets (XL), 300 mg once-daily to the immediate-release formulation of bupropion at 100 mg 3 times daily, equivalence was demonstrated for peak plasma concentration and area under the curve for bupropion and the three metabolites (hydroxybupropion, threohydrobupropion, and erythrohydrobupropion). Additionally, in a study comparing 14-day dosing with bupropion hydrochloride extended-release tablets (XL) 300 mg once daily to the sustained-release formulation of bupropion at 150 mg 2 times daily, equivalence was demonstrated for peak plasma concentration and area under the curve for bupropion and the three metabolites. Bupropion hydrochloride extended-release tablets (SR) can be taken with or without food. Bupropion Cmax and AUC were increased by 11% to 35% and 16% to 19%, respectively, when bupropion hydrochloride extended-release tablets (SR) was administered with food to healthy volunteers in three trials. The food effect is not considered clinically significant. Following a single-dose administration of bupropion hydrochloride extended-release tablets (SR) in humans, Cmax of bupropion's metabolite hydroxybupropion occurs approximately 6 hours post-dose and is approximately 10 times the peak level of the parent drug at steady state. The elimination half-life of hydroxybupropion is approximately 20 (±5) hours and its AUC at steady state is about 17 times that of bupropion. The times to peak concentrations for the erythrohydrobupropion and threohydrobupropion metabolites are similar to that of the hydroxybupropion metabolite. However, their elimination half-lives are longer, 33(±10) and 37 (±13) hours, respectively, and steady-state AUCs are 1.5 and 7 times that of bupropion, respectively. •Absorption (Drug B): No absorption available •Volume of distribution (Drug A): No volume of distribution available •Volume of distribution (Drug B): No volume of distribution available •Protein binding (Drug A): In vitro tests show that bupropion is 84% bound to human plasma proteins at concentrations up to 200 mcg per mL. The extent of protein binding of the hydroxybupropion metabolite is similar to that for bupropion, whereas the extent of protein binding of the threohydrobupropion metabolite is about half that seen with bupropion. •Protein binding (Drug B): No protein binding available •Metabolism (Drug A): Bupropion is extensively metabolized in humans. Three metabolites are active: hydroxybupropion, which is formed via hydroxylation of the tert-butyl group of bupropion, and the amino-alcohol isomers, threohydrobupropion and erythrohydrobupropion, which are formed via reduction of the carbonyl group. In vitro findings suggest that CYP2B6 is the principal isoenzyme involved in the formation of hydroxybupropion, while cytochrome P450 enzymes are not involved in the formation of threohydrobupropion. Hydroxybupropion has been shown to have the same affinity as bupropion for the norepinephrine transporter (NET) but approximately 50% of its antidepressant activity despite reaching concentrations of ~10-fold higher than that of the parent drug. Oxidation of the bupropion side chain results in the formation of a glycine conjugate of meta-chlorobenzoic acid, which is then excreted as the major urinary metabolite. The potency and toxicity of the metabolites relative to bupropion have not been fully characterized. However, it has been demonstrated in an antidepressant screening test in mice that hydroxybupropion is one-half as potent as bupropion, while threohydrobupropion and erythrohydrobupropion are 5-fold less potent than bupropion. This may be of clinical importance because the plasma concentrations of the metabolites are as high as or higher than those of bupropion. Bupropion and its metabolites exhibit linear kinetics following chronic administration of 300 to 450 mg per day. •Metabolism (Drug B): Renal •Route of elimination (Drug A): Bupropion is extensively metabolized in humans. Oxidation of the bupropion side chain results in the formation of a glycine conjugate of metachlorobenzoic acid, which is then excreted as the major urinary metabolite. Following oral administration of 200 mg of 14C-bupropion in humans, 87% and 10% of the radioactive dose were recovered in the urine and feces, respectively. However, the fraction of the oral dose of bupropion excreted unchanged was only 0.5%, a finding consistent with the extensive metabolism of bupropion. •Route of elimination (Drug B): No route of elimination available •Half-life (Drug A): 24 hours •Half-life (Drug B): 0.55 hours (1st phage), 9 hours (2nd phase) •Clearance (Drug A): No clearance available •Clearance (Drug B): No clearance available •Toxicity (Drug A): Symptoms of overdose include seizures, hallucinations, loss of consciousness, tachycardia, and cardiac arrest. •Toxicity (Drug B): The oral LD50 of oxandrolone in mice and dogs is greater than 5,000 mg/kg. •Brand Names (Drug A): Aplenzin, Auvelity, Budeprion, Contrave, Forfivo, Wellbutrin, Zyban •Brand Names (Drug B): Oxandrin •Synonyms (Drug A): No synonyms listed •Synonyms (Drug B): No synonyms listed •Summary (Drug A): Bupropion is a norepinephrine and dopamine reuptake inhibitor used in the treatment of major depressive disorder (MDD), seasonal affective disorder (SAD), and as an aid to smoking cessation. •Summary (Drug B): Oxandrolone is an androgenic hormone used to treat muscle loss from prolonged corticosteroid treatment and to treat bone pain associated with osteoporosis.

The subject drug is known to be an inhibitor of CYP2C9 while the affected drug is reported to be metabolized by CYP2C9. Concomitant administration of these agents can cause an increase in the serum concentration of the affected drug due to decreased metabolism by CYP2C9, which may result in increased incidence and/or severity of adverse effects related to the affected drug. The severity of the interaction is moderate.

Question: Does Bupropion and Oxandrolone interact? Information: •Drug A: Bupropion •Drug B: Oxandrolone •Severity: MODERATE •Description: The metabolism of Bupropion can be decreased when combined with Oxandrolone. •Extended Description: The subject drug is known to be an inhibitor of CYP2C9 while the affected drug is reported to be metabolized by CYP2C9. Concomitant administration of these agents can cause an increase in the serum concentration of the affected drug due to decreased metabolism by CYP2C9, which may result in increased incidence and/or severity of adverse effects related to the affected drug. •Indication (Drug A): Bupropion is indicated for the treatment of major depressive disorder (MDD), seasonal affective disorder (SAD), and as an aid to smoking cessation. When used in combination with naltrexone as the marketed product ContraveⓇ, bupropion is indicated as an adjunct to a reduced-calorie diet and increased physical activity for chronic weight management in adults with an initial body mass index (BMI) of: 30 kg/m^2 or greater (obese) or 27 kg/m^2 or greater (overweight) in the presence of at least one weight-related comorbid condition (e.g., hypertension, type 2 diabetes mellitus, or dyslipidemia). Bupropion is also used off-label as a first-line treatment in patients with ADHD and comorbid bipolar disorder when used as an adjunct to mood stabilizers. •Indication (Drug B): Use to promote weight gain after weight loss following extensive surgery. •Pharmacodynamics (Drug A): Bupropion is chemically unrelated to tricyclic, tetracyclic, selective serotonin re-uptake inhibitors, or other known antidepressant agents. Compared to classical tricyclic antidepressants, Bupropion is a relatively weak inhibitor of the neuronal uptake of norepinephrine and dopamine. In addition, Bupropion does not inhibit monoamine oxidase. Bupropion has been found to be essentially inactive at the serotonin transporter (SERT)(IC50 >10 000 nM), however both bupropion and its primary metabolite hydroxybupropion have been found to block the function of cation-selective serotonin type 3A receptors (5-HT3ARs). Bupropion produces dose-related central nervous system (CNS) stimulant effects in animals, as evidenced by increased locomotor activity, increased rates of responding in various schedule-controlled operant behaviour tasks, and, at high doses, induction of mild stereotyped behaviour. Due to these stimulant effects and selective activity at dopamine and norepinephrine receptors, bupropion has been identified as having an abuse potential. Bupropion has a similar structure to the controlled substance Cathinone, and has been identified as having mild amphetamine-like activity, particularly when inhaled or injected. Bupropion is also known to lower the seizure threshold, making any pre-existing seizure conditions a contraindication to its use. This risk is exacerbated when bupropion is combined with other drugs or substances that lower the seizure threshold, such as cocaine, or in clinical situations that would increase the risk of a seizure such as abrupt alcohol or benzodiazepine withdrawal. As norepinephrine has been shown to have anticonvulsant properties, bupropion's inhibitory effects on NET are thought to contribute to its pro-convulsant activity. Bupropion has been shown to increase blood pressure and pose a risk for exacerbation of unmanaged or pre-existing hypertension, however, clinical trials of bupropion in smokers with CVD have not identified an increased incidence of CV events including stroke or heart attack. In clinical trials, the mean increase in systolic blood pressure associated with the use of bupropion was found to be 1.3 mmHg. •Pharmacodynamics (Drug B): Oxandrolone is an anabolic steroids indicated as adjunctive therapy to promote weight gain after weight loss following extensive surgery, chronic infections, or severe trauma, and in some patients who without definite pathophysiologic reasons fail to gain or to maintain normal weight, to offset the protein catabolism associated with prolonged administration of corticosteroids, and for the relief of the bone pain frequently accompanying osteoporosis. Anabolic steroids are synthetic derivatives of testosterone. •Mechanism of action (Drug A): Bupropion is a norepinephrine/dopamine-reuptake inhibitor (NDRI) that exerts its pharmacological effects by weakly inhibiting the enzymes involved in the uptake of the neurotransmitters norepinephrine and dopamine from the synaptic cleft, therefore prolonging their duration of action within the neuronal synapse and the downstream effects of these neurotransmitters. More specifically, bupropion binds to the norepinephrine transporter (NET) and the dopamine transporter (DAT). Bupropion was originally classified as an "atypical" antidepressant because it does not exert the same effects as the classical antidepressants such as Monoamine Oxidase Inhibitors (MAOIs), Tricyclic Antidepressants (TCAs), or Selective Serotonin Reuptake Inhibitors (SSRIs). While it has comparable effectiveness to typical first-line options for the treatment of depression such as SSRIs, bupropion is a unique option for the treatment of MDD as it lacks any clinically relevant serotonergic effects, typical of other mood medications, or any effects on histamine or adrenaline receptors. Lack of activity at these receptors results in a more tolerable side effect profile; bupropion is less likely to cause sexual side effects, sedation, or weight gain as compared to SSRIs or TCAs, for example. When used as an aid to smoking cessation, bupropion is thought to confer its anti-craving and anti-withdrawal effects by inhibiting dopamine reuptake, which is thought to be involved in the reward pathways associated with nicotine, and through the antagonism of the nicotinic acetylcholinergic receptor (AChR), thereby blunting the effects of nicotine. Furthermore, the stimulatory effects produced by bupropion in the central nervous system are similar to nicotine's effects, making low doses of bupropion a suitable option as a nicotine substitute. When used in combination with naltrexone in the marketed product ContraveⓇ for chronic weight management, the two components are thought to have effects on areas of the brain involved in the regulation of food intake. This includes the hypothalamus, which is involved in appetite regulation, and the mesolimbic dopamine circuit, which is involved in reward pathways. Studies have shown that the combined activity of bupropion and naltrexone increase the firing rate of hypothalamic pro-opiomelanocortin (POMC) neurons and blockade of opioid receptor-mediated POMC auto-inhibition, which are associated with a reduction in food intake and increased energy expenditure. This combination was also found to reduce food intake when injected directly into the ventral tegmental area of the mesolimbic circuit in mice, which is an area associated with the regulation of reward pathways. •Mechanism of action (Drug B): Oxandrolones interact with androgen receptors in target tissues. •Absorption (Drug A): Bupropion is currently available in 3 distinct, but bioequivalent formulations: immediate release (IR), sustained-release (SR), and extended-release (XL). Immediate Release Formulation In humans, following oral administration of bupropion hydrochloride tablets, peak plasma bupropion concentrations are usually achieved within 2 hours. IR formulations provide a short duration of action and are therefore generally dosed three times per day. Sustained Release Formulation In humans, following oral administration of bupropion hydrochloride sustained-release tablets (SR), peak plasma concentration (Cmax) of bupropion is usually achieved within 3 hours. SR formulations provide a 12-hour extended release of medication and are therefore generally dosed twice per day. Extended Release Formulation Following single oral administration of bupropion hydrochloride extended-release tablets (XL) to healthy volunteers, the median time to peak plasma concentrations for bupropion was approximately 5 hours. The presence of food did not affect the peak concentration or area under the curve of bupropion. XL formulations provide a 24-hour extended release of medication and are therefore generally dosed once per day/ In a trial comparing chronic dosing with bupropion hydrochloride extended-release tablets (SR) 150 mg twice daily to bupropion immediate-release formulation 100 mg 3 times daily, the steady state Cmax for bupropion after bupropion hydrochloride sustained-release tablets (SR) administration was approximately 85% of those achieved after bupropion immediate-release formulation administration. Exposure (AUC) to bupropion was equivalent for both formulations. Bioequivalence was also demonstrated for all three major active metabolites (i.e., hydroxybupropion, threohydrobupropion and erythrohydrobupropion) for both Cmax and AUC. Thus, at steady state, bupropion hydrochloride sustained-release tablets (SR) given twice daily, and the immediate-release formulation of bupropion given 3 times daily, are essentially bioequivalent for both bupropion and the 3 quantitatively important metabolites. Furthermore, in a study comparing 14-day dosing with bupropion hydrochloride extended-release tablets (XL), 300 mg once-daily to the immediate-release formulation of bupropion at 100 mg 3 times daily, equivalence was demonstrated for peak plasma concentration and area under the curve for bupropion and the three metabolites (hydroxybupropion, threohydrobupropion, and erythrohydrobupropion). Additionally, in a study comparing 14-day dosing with bupropion hydrochloride extended-release tablets (XL) 300 mg once daily to the sustained-release formulation of bupropion at 150 mg 2 times daily, equivalence was demonstrated for peak plasma concentration and area under the curve for bupropion and the three metabolites. Bupropion hydrochloride extended-release tablets (SR) can be taken with or without food. Bupropion Cmax and AUC were increased by 11% to 35% and 16% to 19%, respectively, when bupropion hydrochloride extended-release tablets (SR) was administered with food to healthy volunteers in three trials. The food effect is not considered clinically significant. Following a single-dose administration of bupropion hydrochloride extended-release tablets (SR) in humans, Cmax of bupropion's metabolite hydroxybupropion occurs approximately 6 hours post-dose and is approximately 10 times the peak level of the parent drug at steady state. The elimination half-life of hydroxybupropion is approximately 20 (±5) hours and its AUC at steady state is about 17 times that of bupropion. The times to peak concentrations for the erythrohydrobupropion and threohydrobupropion metabolites are similar to that of the hydroxybupropion metabolite. However, their elimination half-lives are longer, 33(±10) and 37 (±13) hours, respectively, and steady-state AUCs are 1.5 and 7 times that of bupropion, respectively. •Absorption (Drug B): No absorption available •Volume of distribution (Drug A): No volume of distribution available •Volume of distribution (Drug B): No volume of distribution available •Protein binding (Drug A): In vitro tests show that bupropion is 84% bound to human plasma proteins at concentrations up to 200 mcg per mL. The extent of protein binding of the hydroxybupropion metabolite is similar to that for bupropion, whereas the extent of protein binding of the threohydrobupropion metabolite is about half that seen with bupropion. •Protein binding (Drug B): No protein binding available •Metabolism (Drug A): Bupropion is extensively metabolized in humans. Three metabolites are active: hydroxybupropion, which is formed via hydroxylation of the tert-butyl group of bupropion, and the amino-alcohol isomers, threohydrobupropion and erythrohydrobupropion, which are formed via reduction of the carbonyl group. In vitro findings suggest that CYP2B6 is the principal isoenzyme involved in the formation of hydroxybupropion, while cytochrome P450 enzymes are not involved in the formation of threohydrobupropion. Hydroxybupropion has been shown to have the same affinity as bupropion for the norepinephrine transporter (NET) but approximately 50% of its antidepressant activity despite reaching concentrations of ~10-fold higher than that of the parent drug. Oxidation of the bupropion side chain results in the formation of a glycine conjugate of meta-chlorobenzoic acid, which is then excreted as the major urinary metabolite. The potency and toxicity of the metabolites relative to bupropion have not been fully characterized. However, it has been demonstrated in an antidepressant screening test in mice that hydroxybupropion is one-half as potent as bupropion, while threohydrobupropion and erythrohydrobupropion are 5-fold less potent than bupropion. This may be of clinical importance because the plasma concentrations of the metabolites are as high as or higher than those of bupropion. Bupropion and its metabolites exhibit linear kinetics following chronic administration of 300 to 450 mg per day. •Metabolism (Drug B): Renal •Route of elimination (Drug A): Bupropion is extensively metabolized in humans. Oxidation of the bupropion side chain results in the formation of a glycine conjugate of metachlorobenzoic acid, which is then excreted as the major urinary metabolite. Following oral administration of 200 mg of 14C-bupropion in humans, 87% and 10% of the radioactive dose were recovered in the urine and feces, respectively. However, the fraction of the oral dose of bupropion excreted unchanged was only 0.5%, a finding consistent with the extensive metabolism of bupropion. •Route of elimination (Drug B): No route of elimination available •Half-life (Drug A): 24 hours •Half-life (Drug B): 0.55 hours (1st phage), 9 hours (2nd phase) •Clearance (Drug A): No clearance available •Clearance (Drug B): No clearance available •Toxicity (Drug A): Symptoms of overdose include seizures, hallucinations, loss of consciousness, tachycardia, and cardiac arrest. •Toxicity (Drug B): The oral LD50 of oxandrolone in mice and dogs is greater than 5,000 mg/kg. •Brand Names (Drug A): Aplenzin, Auvelity, Budeprion, Contrave, Forfivo, Wellbutrin, Zyban •Brand Names (Drug B): Oxandrin •Synonyms (Drug A): No synonyms listed •Synonyms (Drug B): No synonyms listed •Summary (Drug A): Bupropion is a norepinephrine and dopamine reuptake inhibitor used in the treatment of major depressive disorder (MDD), seasonal affective disorder (SAD), and as an aid to smoking cessation. •Summary (Drug B): Oxandrolone is an androgenic hormone used to treat muscle loss from prolonged corticosteroid treatment and to treat bone pain associated with osteoporosis. Output: The subject drug is known to be an inhibitor of CYP2C9 while the affected drug is reported to be metabolized by CYP2C9. Concomitant administration of these agents can cause an increase in the serum concentration of the affected drug due to decreased metabolism by CYP2C9, which may result in increased incidence and/or severity of adverse effects related to the affected drug. The severity of the interaction is moderate.

Does Bupropion and Oxaprozin interact?

•Drug A: Bupropion •Drug B: Oxaprozin •Severity: MINOR •Description: Oxaprozin may decrease the excretion rate of Bupropion which could result in a higher serum level. •Extended Description: The subject drug is a nephrotoxic agent that may potentially impair renal function and decrease the excretion of drugs that mainly undergo renal excretion as the principal mode of clearance, such as the affected drug. Attenuated renal excretion of the affected drug may increase drug concentrations, leading to an elevated risk for drug-related adverse effects. •Indication (Drug A): Bupropion is indicated for the treatment of major depressive disorder (MDD), seasonal affective disorder (SAD), and as an aid to smoking cessation. When used in combination with naltrexone as the marketed product ContraveⓇ, bupropion is indicated as an adjunct to a reduced-calorie diet and increased physical activity for chronic weight management in adults with an initial body mass index (BMI) of: 30 kg/m^2 or greater (obese) or 27 kg/m^2 or greater (overweight) in the presence of at least one weight-related comorbid condition (e.g., hypertension, type 2 diabetes mellitus, or dyslipidemia). Bupropion is also used off-label as a first-line treatment in patients with ADHD and comorbid bipolar disorder when used as an adjunct to mood stabilizers. •Indication (Drug B): Used to relieve the inflammation, swelling, stiffness, and joint pain associated with rheumatoid arthritis and osteoarthritis. •Pharmacodynamics (Drug A): Bupropion is chemically unrelated to tricyclic, tetracyclic, selective serotonin re-uptake inhibitors, or other known antidepressant agents. Compared to classical tricyclic antidepressants, Bupropion is a relatively weak inhibitor of the neuronal uptake of norepinephrine and dopamine. In addition, Bupropion does not inhibit monoamine oxidase. Bupropion has been found to be essentially inactive at the serotonin transporter (SERT)(IC50 >10 000 nM), however both bupropion and its primary metabolite hydroxybupropion have been found to block the function of cation-selective serotonin type 3A receptors (5-HT3ARs). Bupropion produces dose-related central nervous system (CNS) stimulant effects in animals, as evidenced by increased locomotor activity, increased rates of responding in various schedule-controlled operant behaviour tasks, and, at high doses, induction of mild stereotyped behaviour. Due to these stimulant effects and selective activity at dopamine and norepinephrine receptors, bupropion has been identified as having an abuse potential. Bupropion has a similar structure to the controlled substance Cathinone, and has been identified as having mild amphetamine-like activity, particularly when inhaled or injected. Bupropion is also known to lower the seizure threshold, making any pre-existing seizure conditions a contraindication to its use. This risk is exacerbated when bupropion is combined with other drugs or substances that lower the seizure threshold, such as cocaine, or in clinical situations that would increase the risk of a seizure such as abrupt alcohol or benzodiazepine withdrawal. As norepinephrine has been shown to have anticonvulsant properties, bupropion's inhibitory effects on NET are thought to contribute to its pro-convulsant activity. Bupropion has been shown to increase blood pressure and pose a risk for exacerbation of unmanaged or pre-existing hypertension, however, clinical trials of bupropion in smokers with CVD have not identified an increased incidence of CV events including stroke or heart attack. In clinical trials, the mean increase in systolic blood pressure associated with the use of bupropion was found to be 1.3 mmHg. •Pharmacodynamics (Drug B): Oxaprozin is a nonsteroidal anti-inflammatory drug (NSAID) with analgesic and antipyretic properties. Oxaprozin is used to treat rheumatoid arthritis, osteoarthritis, dysmenorrhea, and to alleviate moderate pain. •Mechanism of action (Drug A): Bupropion is a norepinephrine/dopamine-reuptake inhibitor (NDRI) that exerts its pharmacological effects by weakly inhibiting the enzymes involved in the uptake of the neurotransmitters norepinephrine and dopamine from the synaptic cleft, therefore prolonging their duration of action within the neuronal synapse and the downstream effects of these neurotransmitters. More specifically, bupropion binds to the norepinephrine transporter (NET) and the dopamine transporter (DAT). Bupropion was originally classified as an "atypical" antidepressant because it does not exert the same effects as the classical antidepressants such as Monoamine Oxidase Inhibitors (MAOIs), Tricyclic Antidepressants (TCAs), or Selective Serotonin Reuptake Inhibitors (SSRIs). While it has comparable effectiveness to typical first-line options for the treatment of depression such as SSRIs, bupropion is a unique option for the treatment of MDD as it lacks any clinically relevant serotonergic effects, typical of other mood medications, or any effects on histamine or adrenaline receptors. Lack of activity at these receptors results in a more tolerable side effect profile; bupropion is less likely to cause sexual side effects, sedation, or weight gain as compared to SSRIs or TCAs, for example. When used as an aid to smoking cessation, bupropion is thought to confer its anti-craving and anti-withdrawal effects by inhibiting dopamine reuptake, which is thought to be involved in the reward pathways associated with nicotine, and through the antagonism of the nicotinic acetylcholinergic receptor (AChR), thereby blunting the effects of nicotine. Furthermore, the stimulatory effects produced by bupropion in the central nervous system are similar to nicotine's effects, making low doses of bupropion a suitable option as a nicotine substitute. When used in combination with naltrexone in the marketed product ContraveⓇ for chronic weight management, the two components are thought to have effects on areas of the brain involved in the regulation of food intake. This includes the hypothalamus, which is involved in appetite regulation, and the mesolimbic dopamine circuit, which is involved in reward pathways. Studies have shown that the combined activity of bupropion and naltrexone increase the firing rate of hypothalamic pro-opiomelanocortin (POMC) neurons and blockade of opioid receptor-mediated POMC auto-inhibition, which are associated with a reduction in food intake and increased energy expenditure. This combination was also found to reduce food intake when injected directly into the ventral tegmental area of the mesolimbic circuit in mice, which is an area associated with the regulation of reward pathways. •Mechanism of action (Drug B): Anti-inflammatory effects of Oxaprozin are believed to be due to inhibition of cylooxygenase in platelets which leads to the blockage of prostaglandin synthesis. Antipyretic effects may be due to action on the hypothalamus, resulting in an increased peripheral blood flow, vasodilation, and subsequent heat dissipation. Oxaprozin is a non-selective NSAID, with a cell assay system showing lower COX-2 selectivity implying higher COX-1 selectivity. •Absorption (Drug A): Bupropion is currently available in 3 distinct, but bioequivalent formulations: immediate release (IR), sustained-release (SR), and extended-release (XL). Immediate Release Formulation In humans, following oral administration of bupropion hydrochloride tablets, peak plasma bupropion concentrations are usually achieved within 2 hours. IR formulations provide a short duration of action and are therefore generally dosed three times per day. Sustained Release Formulation In humans, following oral administration of bupropion hydrochloride sustained-release tablets (SR), peak plasma concentration (Cmax) of bupropion is usually achieved within 3 hours. SR formulations provide a 12-hour extended release of medication and are therefore generally dosed twice per day. Extended Release Formulation Following single oral administration of bupropion hydrochloride extended-release tablets (XL) to healthy volunteers, the median time to peak plasma concentrations for bupropion was approximately 5 hours. The presence of food did not affect the peak concentration or area under the curve of bupropion. XL formulations provide a 24-hour extended release of medication and are therefore generally dosed once per day/ In a trial comparing chronic dosing with bupropion hydrochloride extended-release tablets (SR) 150 mg twice daily to bupropion immediate-release formulation 100 mg 3 times daily, the steady state Cmax for bupropion after bupropion hydrochloride sustained-release tablets (SR) administration was approximately 85% of those achieved after bupropion immediate-release formulation administration. Exposure (AUC) to bupropion was equivalent for both formulations. Bioequivalence was also demonstrated for all three major active metabolites (i.e., hydroxybupropion, threohydrobupropion and erythrohydrobupropion) for both Cmax and AUC. Thus, at steady state, bupropion hydrochloride sustained-release tablets (SR) given twice daily, and the immediate-release formulation of bupropion given 3 times daily, are essentially bioequivalent for both bupropion and the 3 quantitatively important metabolites. Furthermore, in a study comparing 14-day dosing with bupropion hydrochloride extended-release tablets (XL), 300 mg once-daily to the immediate-release formulation of bupropion at 100 mg 3 times daily, equivalence was demonstrated for peak plasma concentration and area under the curve for bupropion and the three metabolites (hydroxybupropion, threohydrobupropion, and erythrohydrobupropion). Additionally, in a study comparing 14-day dosing with bupropion hydrochloride extended-release tablets (XL) 300 mg once daily to the sustained-release formulation of bupropion at 150 mg 2 times daily, equivalence was demonstrated for peak plasma concentration and area under the curve for bupropion and the three metabolites. Bupropion hydrochloride extended-release tablets (SR) can be taken with or without food. Bupropion Cmax and AUC were increased by 11% to 35% and 16% to 19%, respectively, when bupropion hydrochloride extended-release tablets (SR) was administered with food to healthy volunteers in three trials. The food effect is not considered clinically significant. Following a single-dose administration of bupropion hydrochloride extended-release tablets (SR) in humans, Cmax of bupropion's metabolite hydroxybupropion occurs approximately 6 hours post-dose and is approximately 10 times the peak level of the parent drug at steady state. The elimination half-life of hydroxybupropion is approximately 20 (±5) hours and its AUC at steady state is about 17 times that of bupropion. The times to peak concentrations for the erythrohydrobupropion and threohydrobupropion metabolites are similar to that of the hydroxybupropion metabolite. However, their elimination half-lives are longer, 33(±10) and 37 (±13) hours, respectively, and steady-state AUCs are 1.5 and 7 times that of bupropion, respectively. •Absorption (Drug B): Oxaprozin is 95% absorbed after oral administration. Food may reduce the rate of absorption of oxaprozin, but the extent of absorption is unchanged. Antacids do not significantly affect the extent and rate of oxaprozin absorption. •Volume of distribution (Drug A): No volume of distribution available •Volume of distribution (Drug B): 11 to 17 L/70 kg •Protein binding (Drug A): In vitro tests show that bupropion is 84% bound to human plasma proteins at concentrations up to 200 mcg per mL. The extent of protein binding of the hydroxybupropion metabolite is similar to that for bupropion, whereas the extent of protein binding of the threohydrobupropion metabolite is about half that seen with bupropion. •Protein binding (Drug B): >99.5% bound to albumin •Metabolism (Drug A): Bupropion is extensively metabolized in humans. Three metabolites are active: hydroxybupropion, which is formed via hydroxylation of the tert-butyl group of bupropion, and the amino-alcohol isomers, threohydrobupropion and erythrohydrobupropion, which are formed via reduction of the carbonyl group. In vitro findings suggest that CYP2B6 is the principal isoenzyme involved in the formation of hydroxybupropion, while cytochrome P450 enzymes are not involved in the formation of threohydrobupropion. Hydroxybupropion has been shown to have the same affinity as bupropion for the norepinephrine transporter (NET) but approximately 50% of its antidepressant activity despite reaching concentrations of ~10-fold higher than that of the parent drug. Oxidation of the bupropion side chain results in the formation of a glycine conjugate of meta-chlorobenzoic acid, which is then excreted as the major urinary metabolite. The potency and toxicity of the metabolites relative to bupropion have not been fully characterized. However, it has been demonstrated in an antidepressant screening test in mice that hydroxybupropion is one-half as potent as bupropion, while threohydrobupropion and erythrohydrobupropion are 5-fold less potent than bupropion. This may be of clinical importance because the plasma concentrations of the metabolites are as high as or higher than those of bupropion. Bupropion and its metabolites exhibit linear kinetics following chronic administration of 300 to 450 mg per day. •Metabolism (Drug B): Hepatic. Ester and ether glucuronide are the major conjugated metabolites of oxaprozin, and do not have significant pharmacologic activity. •Route of elimination (Drug A): Bupropion is extensively metabolized in humans. Oxidation of the bupropion side chain results in the formation of a glycine conjugate of metachlorobenzoic acid, which is then excreted as the major urinary metabolite. Following oral administration of 200 mg of 14C-bupropion in humans, 87% and 10% of the radioactive dose were recovered in the urine and feces, respectively. However, the fraction of the oral dose of bupropion excreted unchanged was only 0.5%, a finding consistent with the extensive metabolism of bupropion. •Route of elimination (Drug B): Oxaprozin is expected to be excreted in human milk based on its physical-chemical properties; however, the amount of oxaprozin excreted in breast milk has not been evaluated. Approximately 95% of oxaprozin is metabolized by the liver. Approximately 5% of the oxaprozin dose is excreted unchanged in the urine. Sixty-five percent (65%) of the dose is excreted in the urine and 35% in the feces as metabolite. Biliary excretion of unchanged oxaprozin is a minor pathway. Several oxaprozin metabolites have been identified in human urine or feces. •Half-life (Drug A): 24 hours •Half-life (Drug B): 54.9 hours •Clearance (Drug A): No clearance available •Clearance (Drug B): No clearance available •Toxicity (Drug A): Symptoms of overdose include seizures, hallucinations, loss of consciousness, tachycardia, and cardiac arrest. •Toxicity (Drug B): Oral, mouse: LD 50 = 1210 mg/kg; Oral, rabbit: LD 50 = 172 mg/kg; Oral, rat: LD 50 = 4470 mg/kg •Brand Names (Drug A): Aplenzin, Auvelity, Budeprion, Contrave, Forfivo, Wellbutrin, Zyban •Brand Names (Drug B): Coxanto, Daypro •Synonyms (Drug A): No synonyms listed •Synonyms (Drug B): No synonyms listed •Summary (Drug A): Bupropion is a norepinephrine and dopamine reuptake inhibitor used in the treatment of major depressive disorder (MDD), seasonal affective disorder (SAD), and as an aid to smoking cessation. •Summary (Drug B): Oxaprozin is an NSAID used to treat osteoarthritis, rheumatoid arthritis, and juvenile rheumatoid arthritis.

The subject drug is a nephrotoxic agent that may potentially impair renal function and decrease the excretion of drugs that mainly undergo renal excretion as the principal mode of clearance, such as the affected drug. Attenuated renal excretion of the affected drug may increase drug concentrations, leading to an elevated risk for drug-related adverse effects. The severity of the interaction is minor.

Question: Does Bupropion and Oxaprozin interact? Information: •Drug A: Bupropion •Drug B: Oxaprozin •Severity: MINOR •Description: Oxaprozin may decrease the excretion rate of Bupropion which could result in a higher serum level. •Extended Description: The subject drug is a nephrotoxic agent that may potentially impair renal function and decrease the excretion of drugs that mainly undergo renal excretion as the principal mode of clearance, such as the affected drug. Attenuated renal excretion of the affected drug may increase drug concentrations, leading to an elevated risk for drug-related adverse effects. •Indication (Drug A): Bupropion is indicated for the treatment of major depressive disorder (MDD), seasonal affective disorder (SAD), and as an aid to smoking cessation. When used in combination with naltrexone as the marketed product ContraveⓇ, bupropion is indicated as an adjunct to a reduced-calorie diet and increased physical activity for chronic weight management in adults with an initial body mass index (BMI) of: 30 kg/m^2 or greater (obese) or 27 kg/m^2 or greater (overweight) in the presence of at least one weight-related comorbid condition (e.g., hypertension, type 2 diabetes mellitus, or dyslipidemia). Bupropion is also used off-label as a first-line treatment in patients with ADHD and comorbid bipolar disorder when used as an adjunct to mood stabilizers. •Indication (Drug B): Used to relieve the inflammation, swelling, stiffness, and joint pain associated with rheumatoid arthritis and osteoarthritis. •Pharmacodynamics (Drug A): Bupropion is chemically unrelated to tricyclic, tetracyclic, selective serotonin re-uptake inhibitors, or other known antidepressant agents. Compared to classical tricyclic antidepressants, Bupropion is a relatively weak inhibitor of the neuronal uptake of norepinephrine and dopamine. In addition, Bupropion does not inhibit monoamine oxidase. Bupropion has been found to be essentially inactive at the serotonin transporter (SERT)(IC50 >10 000 nM), however both bupropion and its primary metabolite hydroxybupropion have been found to block the function of cation-selective serotonin type 3A receptors (5-HT3ARs). Bupropion produces dose-related central nervous system (CNS) stimulant effects in animals, as evidenced by increased locomotor activity, increased rates of responding in various schedule-controlled operant behaviour tasks, and, at high doses, induction of mild stereotyped behaviour. Due to these stimulant effects and selective activity at dopamine and norepinephrine receptors, bupropion has been identified as having an abuse potential. Bupropion has a similar structure to the controlled substance Cathinone, and has been identified as having mild amphetamine-like activity, particularly when inhaled or injected. Bupropion is also known to lower the seizure threshold, making any pre-existing seizure conditions a contraindication to its use. This risk is exacerbated when bupropion is combined with other drugs or substances that lower the seizure threshold, such as cocaine, or in clinical situations that would increase the risk of a seizure such as abrupt alcohol or benzodiazepine withdrawal. As norepinephrine has been shown to have anticonvulsant properties, bupropion's inhibitory effects on NET are thought to contribute to its pro-convulsant activity. Bupropion has been shown to increase blood pressure and pose a risk for exacerbation of unmanaged or pre-existing hypertension, however, clinical trials of bupropion in smokers with CVD have not identified an increased incidence of CV events including stroke or heart attack. In clinical trials, the mean increase in systolic blood pressure associated with the use of bupropion was found to be 1.3 mmHg. •Pharmacodynamics (Drug B): Oxaprozin is a nonsteroidal anti-inflammatory drug (NSAID) with analgesic and antipyretic properties. Oxaprozin is used to treat rheumatoid arthritis, osteoarthritis, dysmenorrhea, and to alleviate moderate pain. •Mechanism of action (Drug A): Bupropion is a norepinephrine/dopamine-reuptake inhibitor (NDRI) that exerts its pharmacological effects by weakly inhibiting the enzymes involved in the uptake of the neurotransmitters norepinephrine and dopamine from the synaptic cleft, therefore prolonging their duration of action within the neuronal synapse and the downstream effects of these neurotransmitters. More specifically, bupropion binds to the norepinephrine transporter (NET) and the dopamine transporter (DAT). Bupropion was originally classified as an "atypical" antidepressant because it does not exert the same effects as the classical antidepressants such as Monoamine Oxidase Inhibitors (MAOIs), Tricyclic Antidepressants (TCAs), or Selective Serotonin Reuptake Inhibitors (SSRIs). While it has comparable effectiveness to typical first-line options for the treatment of depression such as SSRIs, bupropion is a unique option for the treatment of MDD as it lacks any clinically relevant serotonergic effects, typical of other mood medications, or any effects on histamine or adrenaline receptors. Lack of activity at these receptors results in a more tolerable side effect profile; bupropion is less likely to cause sexual side effects, sedation, or weight gain as compared to SSRIs or TCAs, for example. When used as an aid to smoking cessation, bupropion is thought to confer its anti-craving and anti-withdrawal effects by inhibiting dopamine reuptake, which is thought to be involved in the reward pathways associated with nicotine, and through the antagonism of the nicotinic acetylcholinergic receptor (AChR), thereby blunting the effects of nicotine. Furthermore, the stimulatory effects produced by bupropion in the central nervous system are similar to nicotine's effects, making low doses of bupropion a suitable option as a nicotine substitute. When used in combination with naltrexone in the marketed product ContraveⓇ for chronic weight management, the two components are thought to have effects on areas of the brain involved in the regulation of food intake. This includes the hypothalamus, which is involved in appetite regulation, and the mesolimbic dopamine circuit, which is involved in reward pathways. Studies have shown that the combined activity of bupropion and naltrexone increase the firing rate of hypothalamic pro-opiomelanocortin (POMC) neurons and blockade of opioid receptor-mediated POMC auto-inhibition, which are associated with a reduction in food intake and increased energy expenditure. This combination was also found to reduce food intake when injected directly into the ventral tegmental area of the mesolimbic circuit in mice, which is an area associated with the regulation of reward pathways. •Mechanism of action (Drug B): Anti-inflammatory effects of Oxaprozin are believed to be due to inhibition of cylooxygenase in platelets which leads to the blockage of prostaglandin synthesis. Antipyretic effects may be due to action on the hypothalamus, resulting in an increased peripheral blood flow, vasodilation, and subsequent heat dissipation. Oxaprozin is a non-selective NSAID, with a cell assay system showing lower COX-2 selectivity implying higher COX-1 selectivity. •Absorption (Drug A): Bupropion is currently available in 3 distinct, but bioequivalent formulations: immediate release (IR), sustained-release (SR), and extended-release (XL). Immediate Release Formulation In humans, following oral administration of bupropion hydrochloride tablets, peak plasma bupropion concentrations are usually achieved within 2 hours. IR formulations provide a short duration of action and are therefore generally dosed three times per day. Sustained Release Formulation In humans, following oral administration of bupropion hydrochloride sustained-release tablets (SR), peak plasma concentration (Cmax) of bupropion is usually achieved within 3 hours. SR formulations provide a 12-hour extended release of medication and are therefore generally dosed twice per day. Extended Release Formulation Following single oral administration of bupropion hydrochloride extended-release tablets (XL) to healthy volunteers, the median time to peak plasma concentrations for bupropion was approximately 5 hours. The presence of food did not affect the peak concentration or area under the curve of bupropion. XL formulations provide a 24-hour extended release of medication and are therefore generally dosed once per day/ In a trial comparing chronic dosing with bupropion hydrochloride extended-release tablets (SR) 150 mg twice daily to bupropion immediate-release formulation 100 mg 3 times daily, the steady state Cmax for bupropion after bupropion hydrochloride sustained-release tablets (SR) administration was approximately 85% of those achieved after bupropion immediate-release formulation administration. Exposure (AUC) to bupropion was equivalent for both formulations. Bioequivalence was also demonstrated for all three major active metabolites (i.e., hydroxybupropion, threohydrobupropion and erythrohydrobupropion) for both Cmax and AUC. Thus, at steady state, bupropion hydrochloride sustained-release tablets (SR) given twice daily, and the immediate-release formulation of bupropion given 3 times daily, are essentially bioequivalent for both bupropion and the 3 quantitatively important metabolites. Furthermore, in a study comparing 14-day dosing with bupropion hydrochloride extended-release tablets (XL), 300 mg once-daily to the immediate-release formulation of bupropion at 100 mg 3 times daily, equivalence was demonstrated for peak plasma concentration and area under the curve for bupropion and the three metabolites (hydroxybupropion, threohydrobupropion, and erythrohydrobupropion). Additionally, in a study comparing 14-day dosing with bupropion hydrochloride extended-release tablets (XL) 300 mg once daily to the sustained-release formulation of bupropion at 150 mg 2 times daily, equivalence was demonstrated for peak plasma concentration and area under the curve for bupropion and the three metabolites. Bupropion hydrochloride extended-release tablets (SR) can be taken with or without food. Bupropion Cmax and AUC were increased by 11% to 35% and 16% to 19%, respectively, when bupropion hydrochloride extended-release tablets (SR) was administered with food to healthy volunteers in three trials. The food effect is not considered clinically significant. Following a single-dose administration of bupropion hydrochloride extended-release tablets (SR) in humans, Cmax of bupropion's metabolite hydroxybupropion occurs approximately 6 hours post-dose and is approximately 10 times the peak level of the parent drug at steady state. The elimination half-life of hydroxybupropion is approximately 20 (±5) hours and its AUC at steady state is about 17 times that of bupropion. The times to peak concentrations for the erythrohydrobupropion and threohydrobupropion metabolites are similar to that of the hydroxybupropion metabolite. However, their elimination half-lives are longer, 33(±10) and 37 (±13) hours, respectively, and steady-state AUCs are 1.5 and 7 times that of bupropion, respectively. •Absorption (Drug B): Oxaprozin is 95% absorbed after oral administration. Food may reduce the rate of absorption of oxaprozin, but the extent of absorption is unchanged. Antacids do not significantly affect the extent and rate of oxaprozin absorption. •Volume of distribution (Drug A): No volume of distribution available •Volume of distribution (Drug B): 11 to 17 L/70 kg •Protein binding (Drug A): In vitro tests show that bupropion is 84% bound to human plasma proteins at concentrations up to 200 mcg per mL. The extent of protein binding of the hydroxybupropion metabolite is similar to that for bupropion, whereas the extent of protein binding of the threohydrobupropion metabolite is about half that seen with bupropion. •Protein binding (Drug B): >99.5% bound to albumin •Metabolism (Drug A): Bupropion is extensively metabolized in humans. Three metabolites are active: hydroxybupropion, which is formed via hydroxylation of the tert-butyl group of bupropion, and the amino-alcohol isomers, threohydrobupropion and erythrohydrobupropion, which are formed via reduction of the carbonyl group. In vitro findings suggest that CYP2B6 is the principal isoenzyme involved in the formation of hydroxybupropion, while cytochrome P450 enzymes are not involved in the formation of threohydrobupropion. Hydroxybupropion has been shown to have the same affinity as bupropion for the norepinephrine transporter (NET) but approximately 50% of its antidepressant activity despite reaching concentrations of ~10-fold higher than that of the parent drug. Oxidation of the bupropion side chain results in the formation of a glycine conjugate of meta-chlorobenzoic acid, which is then excreted as the major urinary metabolite. The potency and toxicity of the metabolites relative to bupropion have not been fully characterized. However, it has been demonstrated in an antidepressant screening test in mice that hydroxybupropion is one-half as potent as bupropion, while threohydrobupropion and erythrohydrobupropion are 5-fold less potent than bupropion. This may be of clinical importance because the plasma concentrations of the metabolites are as high as or higher than those of bupropion. Bupropion and its metabolites exhibit linear kinetics following chronic administration of 300 to 450 mg per day. •Metabolism (Drug B): Hepatic. Ester and ether glucuronide are the major conjugated metabolites of oxaprozin, and do not have significant pharmacologic activity. •Route of elimination (Drug A): Bupropion is extensively metabolized in humans. Oxidation of the bupropion side chain results in the formation of a glycine conjugate of metachlorobenzoic acid, which is then excreted as the major urinary metabolite. Following oral administration of 200 mg of 14C-bupropion in humans, 87% and 10% of the radioactive dose were recovered in the urine and feces, respectively. However, the fraction of the oral dose of bupropion excreted unchanged was only 0.5%, a finding consistent with the extensive metabolism of bupropion. •Route of elimination (Drug B): Oxaprozin is expected to be excreted in human milk based on its physical-chemical properties; however, the amount of oxaprozin excreted in breast milk has not been evaluated. Approximately 95% of oxaprozin is metabolized by the liver. Approximately 5% of the oxaprozin dose is excreted unchanged in the urine. Sixty-five percent (65%) of the dose is excreted in the urine and 35% in the feces as metabolite. Biliary excretion of unchanged oxaprozin is a minor pathway. Several oxaprozin metabolites have been identified in human urine or feces. •Half-life (Drug A): 24 hours •Half-life (Drug B): 54.9 hours •Clearance (Drug A): No clearance available •Clearance (Drug B): No clearance available •Toxicity (Drug A): Symptoms of overdose include seizures, hallucinations, loss of consciousness, tachycardia, and cardiac arrest. •Toxicity (Drug B): Oral, mouse: LD 50 = 1210 mg/kg; Oral, rabbit: LD 50 = 172 mg/kg; Oral, rat: LD 50 = 4470 mg/kg •Brand Names (Drug A): Aplenzin, Auvelity, Budeprion, Contrave, Forfivo, Wellbutrin, Zyban •Brand Names (Drug B): Coxanto, Daypro •Synonyms (Drug A): No synonyms listed •Synonyms (Drug B): No synonyms listed •Summary (Drug A): Bupropion is a norepinephrine and dopamine reuptake inhibitor used in the treatment of major depressive disorder (MDD), seasonal affective disorder (SAD), and as an aid to smoking cessation. •Summary (Drug B): Oxaprozin is an NSAID used to treat osteoarthritis, rheumatoid arthritis, and juvenile rheumatoid arthritis. Output: The subject drug is a nephrotoxic agent that may potentially impair renal function and decrease the excretion of drugs that mainly undergo renal excretion as the principal mode of clearance, such as the affected drug. Attenuated renal excretion of the affected drug may increase drug concentrations, leading to an elevated risk for drug-related adverse effects. The severity of the interaction is minor.

Does Bupropion and Oxazepam interact?

•Drug A: Bupropion •Drug B: Oxazepam •Severity: MODERATE •Description: The risk or severity of CNS depression can be increased when Oxazepam is combined with Bupropion. •Extended Description: Central nervous system (CNS) depressants can cause sedation, falls, respiratory depression, coma, and death.2,3 The potential interaction between a CNS depressant and another CNS depressant drug due to synergistic effects is well documented in the literature, although the risk and severity of CNS depression vary from each drug. The subject and affected drugs are both CNS depressants that, when co-administered, may result in a more profound CNS depression. As the risk and severity of CNS depression resulting from the combined use of CNS depressants vary from each agent, each interaction between CNS depressants should be considered individually. •Indication (Drug A): Bupropion is indicated for the treatment of major depressive disorder (MDD), seasonal affective disorder (SAD), and as an aid to smoking cessation. When used in combination with naltrexone as the marketed product ContraveⓇ, bupropion is indicated as an adjunct to a reduced-calorie diet and increased physical activity for chronic weight management in adults with an initial body mass index (BMI) of: 30 kg/m^2 or greater (obese) or 27 kg/m^2 or greater (overweight) in the presence of at least one weight-related comorbid condition (e.g., hypertension, type 2 diabetes mellitus, or dyslipidemia). Bupropion is also used off-label as a first-line treatment in patients with ADHD and comorbid bipolar disorder when used as an adjunct to mood stabilizers. •Indication (Drug B): Oxazepam is indicated for the management of anxiety disorders and for the short-term relief of symptoms of anxiety. It may also be used in the management of alcohol withdrawal symptoms. •Pharmacodynamics (Drug A): Bupropion is chemically unrelated to tricyclic, tetracyclic, selective serotonin re-uptake inhibitors, or other known antidepressant agents. Compared to classical tricyclic antidepressants, Bupropion is a relatively weak inhibitor of the neuronal uptake of norepinephrine and dopamine. In addition, Bupropion does not inhibit monoamine oxidase. Bupropion has been found to be essentially inactive at the serotonin transporter (SERT)(IC50 >10 000 nM), however both bupropion and its primary metabolite hydroxybupropion have been found to block the function of cation-selective serotonin type 3A receptors (5-HT3ARs). Bupropion produces dose-related central nervous system (CNS) stimulant effects in animals, as evidenced by increased locomotor activity, increased rates of responding in various schedule-controlled operant behaviour tasks, and, at high doses, induction of mild stereotyped behaviour. Due to these stimulant effects and selective activity at dopamine and norepinephrine receptors, bupropion has been identified as having an abuse potential. Bupropion has a similar structure to the controlled substance Cathinone, and has been identified as having mild amphetamine-like activity, particularly when inhaled or injected. Bupropion is also known to lower the seizure threshold, making any pre-existing seizure conditions a contraindication to its use. This risk is exacerbated when bupropion is combined with other drugs or substances that lower the seizure threshold, such as cocaine, or in clinical situations that would increase the risk of a seizure such as abrupt alcohol or benzodiazepine withdrawal. As norepinephrine has been shown to have anticonvulsant properties, bupropion's inhibitory effects on NET are thought to contribute to its pro-convulsant activity. Bupropion has been shown to increase blood pressure and pose a risk for exacerbation of unmanaged or pre-existing hypertension, however, clinical trials of bupropion in smokers with CVD have not identified an increased incidence of CV events including stroke or heart attack. In clinical trials, the mean increase in systolic blood pressure associated with the use of bupropion was found to be 1.3 mmHg. •Pharmacodynamics (Drug B): Benzodiazepines, including oxazepam, exert their sedative and anxiolytic effects by potentiating the effects of endogenous GABA, the primary inhibitory neurotransmitter in the CNS. Compared to other benzodiazepines, it has relatively low potency and a moderate duration of action. Oxazepam should be administered with caution to patients for whom a drop in blood pressure may lead to cardiac complications as, in rare cases, it may cause hypotension. •Mechanism of action (Drug A): Bupropion is a norepinephrine/dopamine-reuptake inhibitor (NDRI) that exerts its pharmacological effects by weakly inhibiting the enzymes involved in the uptake of the neurotransmitters norepinephrine and dopamine from the synaptic cleft, therefore prolonging their duration of action within the neuronal synapse and the downstream effects of these neurotransmitters. More specifically, bupropion binds to the norepinephrine transporter (NET) and the dopamine transporter (DAT). Bupropion was originally classified as an "atypical" antidepressant because it does not exert the same effects as the classical antidepressants such as Monoamine Oxidase Inhibitors (MAOIs), Tricyclic Antidepressants (TCAs), or Selective Serotonin Reuptake Inhibitors (SSRIs). While it has comparable effectiveness to typical first-line options for the treatment of depression such as SSRIs, bupropion is a unique option for the treatment of MDD as it lacks any clinically relevant serotonergic effects, typical of other mood medications, or any effects on histamine or adrenaline receptors. Lack of activity at these receptors results in a more tolerable side effect profile; bupropion is less likely to cause sexual side effects, sedation, or weight gain as compared to SSRIs or TCAs, for example. When used as an aid to smoking cessation, bupropion is thought to confer its anti-craving and anti-withdrawal effects by inhibiting dopamine reuptake, which is thought to be involved in the reward pathways associated with nicotine, and through the antagonism of the nicotinic acetylcholinergic receptor (AChR), thereby blunting the effects of nicotine. Furthermore, the stimulatory effects produced by bupropion in the central nervous system are similar to nicotine's effects, making low doses of bupropion a suitable option as a nicotine substitute. When used in combination with naltrexone in the marketed product ContraveⓇ for chronic weight management, the two components are thought to have effects on areas of the brain involved in the regulation of food intake. This includes the hypothalamus, which is involved in appetite regulation, and the mesolimbic dopamine circuit, which is involved in reward pathways. Studies have shown that the combined activity of bupropion and naltrexone increase the firing rate of hypothalamic pro-opiomelanocortin (POMC) neurons and blockade of opioid receptor-mediated POMC auto-inhibition, which are associated with a reduction in food intake and increased energy expenditure. This combination was also found to reduce food intake when injected directly into the ventral tegmental area of the mesolimbic circuit in mice, which is an area associated with the regulation of reward pathways. •Mechanism of action (Drug B): Like other benzodiazepines, oxazepam exerts its anxiolytic effects by potentiating the effect of gamma-aminobutyric acid (GABA) on GABA(A) receptors, the main inhibitory neurotransmitter receptors in the mammalian brain. GABA(A) receptors are a component of GABA-gated ionotropic chloride channels that produce inhibitory postsynaptic potentials - following activation by GABA, the channel undergoes a conformational change that allows the passage of chloride ions through the channel. The inhibitory potentials produced by GABA neurotransmission play an integral role in the suppression and control of epileptiform nerve firing such as that seen in epilepsy, which makes the GABA system a desirable target in the treatment of epilepsy. Benzodiazepines are positive allosteric modulators of GABA(A) function. They bind to the interface between alpha (α) and gamma (γ) subunits on the receptor, commonly referred to as the benzodiazepine binding site, and modulate the receptor such that its inhibitory response to GABA binding is dramatically increased. •Absorption (Drug A): Bupropion is currently available in 3 distinct, but bioequivalent formulations: immediate release (IR), sustained-release (SR), and extended-release (XL). Immediate Release Formulation In humans, following oral administration of bupropion hydrochloride tablets, peak plasma bupropion concentrations are usually achieved within 2 hours. IR formulations provide a short duration of action and are therefore generally dosed three times per day. Sustained Release Formulation In humans, following oral administration of bupropion hydrochloride sustained-release tablets (SR), peak plasma concentration (Cmax) of bupropion is usually achieved within 3 hours. SR formulations provide a 12-hour extended release of medication and are therefore generally dosed twice per day. Extended Release Formulation Following single oral administration of bupropion hydrochloride extended-release tablets (XL) to healthy volunteers, the median time to peak plasma concentrations for bupropion was approximately 5 hours. The presence of food did not affect the peak concentration or area under the curve of bupropion. XL formulations provide a 24-hour extended release of medication and are therefore generally dosed once per day/ In a trial comparing chronic dosing with bupropion hydrochloride extended-release tablets (SR) 150 mg twice daily to bupropion immediate-release formulation 100 mg 3 times daily, the steady state Cmax for bupropion after bupropion hydrochloride sustained-release tablets (SR) administration was approximately 85% of those achieved after bupropion immediate-release formulation administration. Exposure (AUC) to bupropion was equivalent for both formulations. Bioequivalence was also demonstrated for all three major active metabolites (i.e., hydroxybupropion, threohydrobupropion and erythrohydrobupropion) for both Cmax and AUC. Thus, at steady state, bupropion hydrochloride sustained-release tablets (SR) given twice daily, and the immediate-release formulation of bupropion given 3 times daily, are essentially bioequivalent for both bupropion and the 3 quantitatively important metabolites. Furthermore, in a study comparing 14-day dosing with bupropion hydrochloride extended-release tablets (XL), 300 mg once-daily to the immediate-release formulation of bupropion at 100 mg 3 times daily, equivalence was demonstrated for peak plasma concentration and area under the curve for bupropion and the three metabolites (hydroxybupropion, threohydrobupropion, and erythrohydrobupropion). Additionally, in a study comparing 14-day dosing with bupropion hydrochloride extended-release tablets (XL) 300 mg once daily to the sustained-release formulation of bupropion at 150 mg 2 times daily, equivalence was demonstrated for peak plasma concentration and area under the curve for bupropion and the three metabolites. Bupropion hydrochloride extended-release tablets (SR) can be taken with or without food. Bupropion Cmax and AUC were increased by 11% to 35% and 16% to 19%, respectively, when bupropion hydrochloride extended-release tablets (SR) was administered with food to healthy volunteers in three trials. The food effect is not considered clinically significant. Following a single-dose administration of bupropion hydrochloride extended-release tablets (SR) in humans, Cmax of bupropion's metabolite hydroxybupropion occurs approximately 6 hours post-dose and is approximately 10 times the peak level of the parent drug at steady state. The elimination half-life of hydroxybupropion is approximately 20 (±5) hours and its AUC at steady state is about 17 times that of bupropion. The times to peak concentrations for the erythrohydrobupropion and threohydrobupropion metabolites are similar to that of the hydroxybupropion metabolite. However, their elimination half-lives are longer, 33(±10) and 37 (±13) hours, respectively, and steady-state AUCs are 1.5 and 7 times that of bupropion, respectively. •Absorption (Drug B): Following oral administration, peak plasma levels (C max ) averaged 450 mg/mL and occurred approximately 3 hours (T max ) after dosing. •Volume of distribution (Drug A): No volume of distribution available •Volume of distribution (Drug B): No volume of distribution available •Protein binding (Drug A): In vitro tests show that bupropion is 84% bound to human plasma proteins at concentrations up to 200 mcg per mL. The extent of protein binding of the hydroxybupropion metabolite is similar to that for bupropion, whereas the extent of protein binding of the threohydrobupropion metabolite is about half that seen with bupropion. •Protein binding (Drug B): Plasma protein binding is approximately 89%, likely to albumin. •Metabolism (Drug A): Bupropion is extensively metabolized in humans. Three metabolites are active: hydroxybupropion, which is formed via hydroxylation of the tert-butyl group of bupropion, and the amino-alcohol isomers, threohydrobupropion and erythrohydrobupropion, which are formed via reduction of the carbonyl group. In vitro findings suggest that CYP2B6 is the principal isoenzyme involved in the formation of hydroxybupropion, while cytochrome P450 enzymes are not involved in the formation of threohydrobupropion. Hydroxybupropion has been shown to have the same affinity as bupropion for the norepinephrine transporter (NET) but approximately 50% of its antidepressant activity despite reaching concentrations of ~10-fold higher than that of the parent drug. Oxidation of the bupropion side chain results in the formation of a glycine conjugate of meta-chlorobenzoic acid, which is then excreted as the major urinary metabolite. The potency and toxicity of the metabolites relative to bupropion have not been fully characterized. However, it has been demonstrated in an antidepressant screening test in mice that hydroxybupropion is one-half as potent as bupropion, while threohydrobupropion and erythrohydrobupropion are 5-fold less potent than bupropion. This may be of clinical importance because the plasma concentrations of the metabolites are as high as or higher than those of bupropion. Bupropion and its metabolites exhibit linear kinetics following chronic administration of 300 to 450 mg per day. •Metabolism (Drug B): Oxazepam has a single major inactive metabolite, a glucuronide conjugate. The glucuronidation of the S-isomer is catalyzed by UGT2B15. The glucuronidation of the R-isomer is catalyzed by UGT2B7 and UGT1A9. •Route of elimination (Drug A): Bupropion is extensively metabolized in humans. Oxidation of the bupropion side chain results in the formation of a glycine conjugate of metachlorobenzoic acid, which is then excreted as the major urinary metabolite. Following oral administration of 200 mg of 14C-bupropion in humans, 87% and 10% of the radioactive dose were recovered in the urine and feces, respectively. However, the fraction of the oral dose of bupropion excreted unchanged was only 0.5%, a finding consistent with the extensive metabolism of bupropion. •Route of elimination (Drug B): Oxazepam is primarily eliminated in the urine as its glucuronide metabolite, with the feces containing approximately 21% of the unchanged drug. The majority of an orally ingested dose of oxazepam is excreted within 48 hours. •Half-life (Drug A): 24 hours •Half-life (Drug B): The mean elimination half-life of oxazepam is 8.2 hours. •Clearance (Drug A): No clearance available •Clearance (Drug B): No clearance available •Toxicity (Drug A): Symptoms of overdose include seizures, hallucinations, loss of consciousness, tachycardia, and cardiac arrest. •Toxicity (Drug B): The oral LD 50 in rats and mice is >8000 mg/kg and 1540 mg/kg, respectively. Symptoms of oxazepam overdose are likely to be consistent with its adverse effect profile and range from mild to severe, sometimes fatal, CNS depression. Treatment should include gastric decontamination, via lavage or induced vomiting, followed by symptomatic and supportive measures. The benzodiazepine antagonist flumazenil may be used in hospitalized patients as an adjunct to non-pharmacological management, but may increase the risk of seizure in long-term benzodiazepine users and in cyclic antidepressant overdose. •Brand Names (Drug A): Aplenzin, Auvelity, Budeprion, Contrave, Forfivo, Wellbutrin, Zyban •Brand Names (Drug B): Oxpam •Synonyms (Drug A): No synonyms listed •Synonyms (Drug B): (RS)-Oxazepam Oxazepam •Summary (Drug A): Bupropion is a norepinephrine and dopamine reuptake inhibitor used in the treatment of major depressive disorder (MDD), seasonal affective disorder (SAD), and as an aid to smoking cessation. •Summary (Drug B): Oxazepam is an intermediate-acting benzodiazepine with slow onset commonly used to treat panic disorders, severe anxiety, alcohol withdrawals, and insomnia.

Central nervous system (CNS) depressants can cause sedation, falls, respiratory depression, coma, and death.2,3 The potential interaction between a CNS depressant and another CNS depressant drug due to synergistic effects is well documented in the literature, although the risk and severity of CNS depression vary from each drug. The subject and affected drugs are both CNS depressants that, when co-administered, may result in a more profound CNS depression. As the risk and severity of CNS depression resulting from the combined use of CNS depressants vary from each agent, each interaction between CNS depressants should be considered individually. The severity of the interaction is moderate.

Question: Does Bupropion and Oxazepam interact? Information: •Drug A: Bupropion •Drug B: Oxazepam •Severity: MODERATE •Description: The risk or severity of CNS depression can be increased when Oxazepam is combined with Bupropion. •Extended Description: Central nervous system (CNS) depressants can cause sedation, falls, respiratory depression, coma, and death.2,3 The potential interaction between a CNS depressant and another CNS depressant drug due to synergistic effects is well documented in the literature, although the risk and severity of CNS depression vary from each drug. The subject and affected drugs are both CNS depressants that, when co-administered, may result in a more profound CNS depression. As the risk and severity of CNS depression resulting from the combined use of CNS depressants vary from each agent, each interaction between CNS depressants should be considered individually. •Indication (Drug A): Bupropion is indicated for the treatment of major depressive disorder (MDD), seasonal affective disorder (SAD), and as an aid to smoking cessation. When used in combination with naltrexone as the marketed product ContraveⓇ, bupropion is indicated as an adjunct to a reduced-calorie diet and increased physical activity for chronic weight management in adults with an initial body mass index (BMI) of: 30 kg/m^2 or greater (obese) or 27 kg/m^2 or greater (overweight) in the presence of at least one weight-related comorbid condition (e.g., hypertension, type 2 diabetes mellitus, or dyslipidemia). Bupropion is also used off-label as a first-line treatment in patients with ADHD and comorbid bipolar disorder when used as an adjunct to mood stabilizers. •Indication (Drug B): Oxazepam is indicated for the management of anxiety disorders and for the short-term relief of symptoms of anxiety. It may also be used in the management of alcohol withdrawal symptoms. •Pharmacodynamics (Drug A): Bupropion is chemically unrelated to tricyclic, tetracyclic, selective serotonin re-uptake inhibitors, or other known antidepressant agents. Compared to classical tricyclic antidepressants, Bupropion is a relatively weak inhibitor of the neuronal uptake of norepinephrine and dopamine. In addition, Bupropion does not inhibit monoamine oxidase. Bupropion has been found to be essentially inactive at the serotonin transporter (SERT)(IC50 >10 000 nM), however both bupropion and its primary metabolite hydroxybupropion have been found to block the function of cation-selective serotonin type 3A receptors (5-HT3ARs). Bupropion produces dose-related central nervous system (CNS) stimulant effects in animals, as evidenced by increased locomotor activity, increased rates of responding in various schedule-controlled operant behaviour tasks, and, at high doses, induction of mild stereotyped behaviour. Due to these stimulant effects and selective activity at dopamine and norepinephrine receptors, bupropion has been identified as having an abuse potential. Bupropion has a similar structure to the controlled substance Cathinone, and has been identified as having mild amphetamine-like activity, particularly when inhaled or injected. Bupropion is also known to lower the seizure threshold, making any pre-existing seizure conditions a contraindication to its use. This risk is exacerbated when bupropion is combined with other drugs or substances that lower the seizure threshold, such as cocaine, or in clinical situations that would increase the risk of a seizure such as abrupt alcohol or benzodiazepine withdrawal. As norepinephrine has been shown to have anticonvulsant properties, bupropion's inhibitory effects on NET are thought to contribute to its pro-convulsant activity. Bupropion has been shown to increase blood pressure and pose a risk for exacerbation of unmanaged or pre-existing hypertension, however, clinical trials of bupropion in smokers with CVD have not identified an increased incidence of CV events including stroke or heart attack. In clinical trials, the mean increase in systolic blood pressure associated with the use of bupropion was found to be 1.3 mmHg. •Pharmacodynamics (Drug B): Benzodiazepines, including oxazepam, exert their sedative and anxiolytic effects by potentiating the effects of endogenous GABA, the primary inhibitory neurotransmitter in the CNS. Compared to other benzodiazepines, it has relatively low potency and a moderate duration of action. Oxazepam should be administered with caution to patients for whom a drop in blood pressure may lead to cardiac complications as, in rare cases, it may cause hypotension. •Mechanism of action (Drug A): Bupropion is a norepinephrine/dopamine-reuptake inhibitor (NDRI) that exerts its pharmacological effects by weakly inhibiting the enzymes involved in the uptake of the neurotransmitters norepinephrine and dopamine from the synaptic cleft, therefore prolonging their duration of action within the neuronal synapse and the downstream effects of these neurotransmitters. More specifically, bupropion binds to the norepinephrine transporter (NET) and the dopamine transporter (DAT). Bupropion was originally classified as an "atypical" antidepressant because it does not exert the same effects as the classical antidepressants such as Monoamine Oxidase Inhibitors (MAOIs), Tricyclic Antidepressants (TCAs), or Selective Serotonin Reuptake Inhibitors (SSRIs). While it has comparable effectiveness to typical first-line options for the treatment of depression such as SSRIs, bupropion is a unique option for the treatment of MDD as it lacks any clinically relevant serotonergic effects, typical of other mood medications, or any effects on histamine or adrenaline receptors. Lack of activity at these receptors results in a more tolerable side effect profile; bupropion is less likely to cause sexual side effects, sedation, or weight gain as compared to SSRIs or TCAs, for example. When used as an aid to smoking cessation, bupropion is thought to confer its anti-craving and anti-withdrawal effects by inhibiting dopamine reuptake, which is thought to be involved in the reward pathways associated with nicotine, and through the antagonism of the nicotinic acetylcholinergic receptor (AChR), thereby blunting the effects of nicotine. Furthermore, the stimulatory effects produced by bupropion in the central nervous system are similar to nicotine's effects, making low doses of bupropion a suitable option as a nicotine substitute. When used in combination with naltrexone in the marketed product ContraveⓇ for chronic weight management, the two components are thought to have effects on areas of the brain involved in the regulation of food intake. This includes the hypothalamus, which is involved in appetite regulation, and the mesolimbic dopamine circuit, which is involved in reward pathways. Studies have shown that the combined activity of bupropion and naltrexone increase the firing rate of hypothalamic pro-opiomelanocortin (POMC) neurons and blockade of opioid receptor-mediated POMC auto-inhibition, which are associated with a reduction in food intake and increased energy expenditure. This combination was also found to reduce food intake when injected directly into the ventral tegmental area of the mesolimbic circuit in mice, which is an area associated with the regulation of reward pathways. •Mechanism of action (Drug B): Like other benzodiazepines, oxazepam exerts its anxiolytic effects by potentiating the effect of gamma-aminobutyric acid (GABA) on GABA(A) receptors, the main inhibitory neurotransmitter receptors in the mammalian brain. GABA(A) receptors are a component of GABA-gated ionotropic chloride channels that produce inhibitory postsynaptic potentials - following activation by GABA, the channel undergoes a conformational change that allows the passage of chloride ions through the channel. The inhibitory potentials produced by GABA neurotransmission play an integral role in the suppression and control of epileptiform nerve firing such as that seen in epilepsy, which makes the GABA system a desirable target in the treatment of epilepsy. Benzodiazepines are positive allosteric modulators of GABA(A) function. They bind to the interface between alpha (α) and gamma (γ) subunits on the receptor, commonly referred to as the benzodiazepine binding site, and modulate the receptor such that its inhibitory response to GABA binding is dramatically increased. •Absorption (Drug A): Bupropion is currently available in 3 distinct, but bioequivalent formulations: immediate release (IR), sustained-release (SR), and extended-release (XL). Immediate Release Formulation In humans, following oral administration of bupropion hydrochloride tablets, peak plasma bupropion concentrations are usually achieved within 2 hours. IR formulations provide a short duration of action and are therefore generally dosed three times per day. Sustained Release Formulation In humans, following oral administration of bupropion hydrochloride sustained-release tablets (SR), peak plasma concentration (Cmax) of bupropion is usually achieved within 3 hours. SR formulations provide a 12-hour extended release of medication and are therefore generally dosed twice per day. Extended Release Formulation Following single oral administration of bupropion hydrochloride extended-release tablets (XL) to healthy volunteers, the median time to peak plasma concentrations for bupropion was approximately 5 hours. The presence of food did not affect the peak concentration or area under the curve of bupropion. XL formulations provide a 24-hour extended release of medication and are therefore generally dosed once per day/ In a trial comparing chronic dosing with bupropion hydrochloride extended-release tablets (SR) 150 mg twice daily to bupropion immediate-release formulation 100 mg 3 times daily, the steady state Cmax for bupropion after bupropion hydrochloride sustained-release tablets (SR) administration was approximately 85% of those achieved after bupropion immediate-release formulation administration. Exposure (AUC) to bupropion was equivalent for both formulations. Bioequivalence was also demonstrated for all three major active metabolites (i.e., hydroxybupropion, threohydrobupropion and erythrohydrobupropion) for both Cmax and AUC. Thus, at steady state, bupropion hydrochloride sustained-release tablets (SR) given twice daily, and the immediate-release formulation of bupropion given 3 times daily, are essentially bioequivalent for both bupropion and the 3 quantitatively important metabolites. Furthermore, in a study comparing 14-day dosing with bupropion hydrochloride extended-release tablets (XL), 300 mg once-daily to the immediate-release formulation of bupropion at 100 mg 3 times daily, equivalence was demonstrated for peak plasma concentration and area under the curve for bupropion and the three metabolites (hydroxybupropion, threohydrobupropion, and erythrohydrobupropion). Additionally, in a study comparing 14-day dosing with bupropion hydrochloride extended-release tablets (XL) 300 mg once daily to the sustained-release formulation of bupropion at 150 mg 2 times daily, equivalence was demonstrated for peak plasma concentration and area under the curve for bupropion and the three metabolites. Bupropion hydrochloride extended-release tablets (SR) can be taken with or without food. Bupropion Cmax and AUC were increased by 11% to 35% and 16% to 19%, respectively, when bupropion hydrochloride extended-release tablets (SR) was administered with food to healthy volunteers in three trials. The food effect is not considered clinically significant. Following a single-dose administration of bupropion hydrochloride extended-release tablets (SR) in humans, Cmax of bupropion's metabolite hydroxybupropion occurs approximately 6 hours post-dose and is approximately 10 times the peak level of the parent drug at steady state. The elimination half-life of hydroxybupropion is approximately 20 (±5) hours and its AUC at steady state is about 17 times that of bupropion. The times to peak concentrations for the erythrohydrobupropion and threohydrobupropion metabolites are similar to that of the hydroxybupropion metabolite. However, their elimination half-lives are longer, 33(±10) and 37 (±13) hours, respectively, and steady-state AUCs are 1.5 and 7 times that of bupropion, respectively. •Absorption (Drug B): Following oral administration, peak plasma levels (C max ) averaged 450 mg/mL and occurred approximately 3 hours (T max ) after dosing. •Volume of distribution (Drug A): No volume of distribution available •Volume of distribution (Drug B): No volume of distribution available •Protein binding (Drug A): In vitro tests show that bupropion is 84% bound to human plasma proteins at concentrations up to 200 mcg per mL. The extent of protein binding of the hydroxybupropion metabolite is similar to that for bupropion, whereas the extent of protein binding of the threohydrobupropion metabolite is about half that seen with bupropion. •Protein binding (Drug B): Plasma protein binding is approximately 89%, likely to albumin. •Metabolism (Drug A): Bupropion is extensively metabolized in humans. Three metabolites are active: hydroxybupropion, which is formed via hydroxylation of the tert-butyl group of bupropion, and the amino-alcohol isomers, threohydrobupropion and erythrohydrobupropion, which are formed via reduction of the carbonyl group. In vitro findings suggest that CYP2B6 is the principal isoenzyme involved in the formation of hydroxybupropion, while cytochrome P450 enzymes are not involved in the formation of threohydrobupropion. Hydroxybupropion has been shown to have the same affinity as bupropion for the norepinephrine transporter (NET) but approximately 50% of its antidepressant activity despite reaching concentrations of ~10-fold higher than that of the parent drug. Oxidation of the bupropion side chain results in the formation of a glycine conjugate of meta-chlorobenzoic acid, which is then excreted as the major urinary metabolite. The potency and toxicity of the metabolites relative to bupropion have not been fully characterized. However, it has been demonstrated in an antidepressant screening test in mice that hydroxybupropion is one-half as potent as bupropion, while threohydrobupropion and erythrohydrobupropion are 5-fold less potent than bupropion. This may be of clinical importance because the plasma concentrations of the metabolites are as high as or higher than those of bupropion. Bupropion and its metabolites exhibit linear kinetics following chronic administration of 300 to 450 mg per day. •Metabolism (Drug B): Oxazepam has a single major inactive metabolite, a glucuronide conjugate. The glucuronidation of the S-isomer is catalyzed by UGT2B15. The glucuronidation of the R-isomer is catalyzed by UGT2B7 and UGT1A9. •Route of elimination (Drug A): Bupropion is extensively metabolized in humans. Oxidation of the bupropion side chain results in the formation of a glycine conjugate of metachlorobenzoic acid, which is then excreted as the major urinary metabolite. Following oral administration of 200 mg of 14C-bupropion in humans, 87% and 10% of the radioactive dose were recovered in the urine and feces, respectively. However, the fraction of the oral dose of bupropion excreted unchanged was only 0.5%, a finding consistent with the extensive metabolism of bupropion. •Route of elimination (Drug B): Oxazepam is primarily eliminated in the urine as its glucuronide metabolite, with the feces containing approximately 21% of the unchanged drug. The majority of an orally ingested dose of oxazepam is excreted within 48 hours. •Half-life (Drug A): 24 hours •Half-life (Drug B): The mean elimination half-life of oxazepam is 8.2 hours. •Clearance (Drug A): No clearance available •Clearance (Drug B): No clearance available •Toxicity (Drug A): Symptoms of overdose include seizures, hallucinations, loss of consciousness, tachycardia, and cardiac arrest. •Toxicity (Drug B): The oral LD 50 in rats and mice is >8000 mg/kg and 1540 mg/kg, respectively. Symptoms of oxazepam overdose are likely to be consistent with its adverse effect profile and range from mild to severe, sometimes fatal, CNS depression. Treatment should include gastric decontamination, via lavage or induced vomiting, followed by symptomatic and supportive measures. The benzodiazepine antagonist flumazenil may be used in hospitalized patients as an adjunct to non-pharmacological management, but may increase the risk of seizure in long-term benzodiazepine users and in cyclic antidepressant overdose. •Brand Names (Drug A): Aplenzin, Auvelity, Budeprion, Contrave, Forfivo, Wellbutrin, Zyban •Brand Names (Drug B): Oxpam •Synonyms (Drug A): No synonyms listed •Synonyms (Drug B): (RS)-Oxazepam Oxazepam •Summary (Drug A): Bupropion is a norepinephrine and dopamine reuptake inhibitor used in the treatment of major depressive disorder (MDD), seasonal affective disorder (SAD), and as an aid to smoking cessation. •Summary (Drug B): Oxazepam is an intermediate-acting benzodiazepine with slow onset commonly used to treat panic disorders, severe anxiety, alcohol withdrawals, and insomnia. Output: Central nervous system (CNS) depressants can cause sedation, falls, respiratory depression, coma, and death.2,3 The potential interaction between a CNS depressant and another CNS depressant drug due to synergistic effects is well documented in the literature, although the risk and severity of CNS depression vary from each drug. The subject and affected drugs are both CNS depressants that, when co-administered, may result in a more profound CNS depression. As the risk and severity of CNS depression resulting from the combined use of CNS depressants vary from each agent, each interaction between CNS depressants should be considered individually. The severity of the interaction is moderate.

Does Bupropion and Oxcarbazepine interact?

•Drug A: Bupropion •Drug B: Oxcarbazepine •Severity: MODERATE •Description: The risk or severity of CNS depression can be increased when Oxcarbazepine is combined with Bupropion. •Extended Description: Central nervous system (CNS) depressants can cause sedation, falls, respiratory depression, coma, and death.2,3 The potential interaction between a CNS depressant and another CNS depressant drug due to synergistic effects is well documented in the literature, although the risk and severity of CNS depression vary from each drug. The subject and affected drugs are both CNS depressants that, when co-administered, may result in a more profound CNS depression. As the risk and severity of CNS depression resulting from the combined use of CNS depressants vary from each agent, each interaction between CNS depressants should be considered individually. •Indication (Drug A): Bupropion is indicated for the treatment of major depressive disorder (MDD), seasonal affective disorder (SAD), and as an aid to smoking cessation. When used in combination with naltrexone as the marketed product ContraveⓇ, bupropion is indicated as an adjunct to a reduced-calorie diet and increased physical activity for chronic weight management in adults with an initial body mass index (BMI) of: 30 kg/m^2 or greater (obese) or 27 kg/m^2 or greater (overweight) in the presence of at least one weight-related comorbid condition (e.g., hypertension, type 2 diabetes mellitus, or dyslipidemia). Bupropion is also used off-label as a first-line treatment in patients with ADHD and comorbid bipolar disorder when used as an adjunct to mood stabilizers. •Indication (Drug B): In the United States, oxcarbazepine is indicated for use as monotherapy or adjunctive therapy in the treatment of partial-onset seizures in adults and as monotherapy in the treatment of partial-onset seizures in pediatric patients aged 4 years and above, and as adjunctive therapy in pediatric patients aged 2 years and above with partial-onset seizures. In Canada, oxcarbazepine is indicated for use as monotherapy or adjunctive therapy in the treatment of partial-onset seizures in patients 6 years of age and older. •Pharmacodynamics (Drug A): Bupropion is chemically unrelated to tricyclic, tetracyclic, selective serotonin re-uptake inhibitors, or other known antidepressant agents. Compared to classical tricyclic antidepressants, Bupropion is a relatively weak inhibitor of the neuronal uptake of norepinephrine and dopamine. In addition, Bupropion does not inhibit monoamine oxidase. Bupropion has been found to be essentially inactive at the serotonin transporter (SERT)(IC50 >10 000 nM), however both bupropion and its primary metabolite hydroxybupropion have been found to block the function of cation-selective serotonin type 3A receptors (5-HT3ARs). Bupropion produces dose-related central nervous system (CNS) stimulant effects in animals, as evidenced by increased locomotor activity, increased rates of responding in various schedule-controlled operant behaviour tasks, and, at high doses, induction of mild stereotyped behaviour. Due to these stimulant effects and selective activity at dopamine and norepinephrine receptors, bupropion has been identified as having an abuse potential. Bupropion has a similar structure to the controlled substance Cathinone, and has been identified as having mild amphetamine-like activity, particularly when inhaled or injected. Bupropion is also known to lower the seizure threshold, making any pre-existing seizure conditions a contraindication to its use. This risk is exacerbated when bupropion is combined with other drugs or substances that lower the seizure threshold, such as cocaine, or in clinical situations that would increase the risk of a seizure such as abrupt alcohol or benzodiazepine withdrawal. As norepinephrine has been shown to have anticonvulsant properties, bupropion's inhibitory effects on NET are thought to contribute to its pro-convulsant activity. Bupropion has been shown to increase blood pressure and pose a risk for exacerbation of unmanaged or pre-existing hypertension, however, clinical trials of bupropion in smokers with CVD have not identified an increased incidence of CV events including stroke or heart attack. In clinical trials, the mean increase in systolic blood pressure associated with the use of bupropion was found to be 1.3 mmHg. •Pharmacodynamics (Drug B): Oxcarbazepine is an anticonvulsant drug that reduces the incidence of seizures in epilepsy by inhibiting abnormal electrical activity in the brain. There have been rare reports of oxcarbazepine resulting in the development of hematologic abnormalities, including agranulocytosis and aplastic anemia. Patients should be undergo frequent laboratory testing and should be monitored closely for signs and symptoms of blood dyscrasias. Oxcarbazepine has also been associated with the development of dermatologic reactions which can progress from a simple rash to potentially fatal reactions such as toxic epidermal necrolysis (TEN) or Stevens-Johnson Syndrome (SJS). Patients with the HLA-A 3101 and/or HLA-B 1502 alleles may be at higher risk of this reaction. Oxcarbazepine should be discontinued at the first sign of a drug-induced skin reaction. •Mechanism of action (Drug A): Bupropion is a norepinephrine/dopamine-reuptake inhibitor (NDRI) that exerts its pharmacological effects by weakly inhibiting the enzymes involved in the uptake of the neurotransmitters norepinephrine and dopamine from the synaptic cleft, therefore prolonging their duration of action within the neuronal synapse and the downstream effects of these neurotransmitters. More specifically, bupropion binds to the norepinephrine transporter (NET) and the dopamine transporter (DAT). Bupropion was originally classified as an "atypical" antidepressant because it does not exert the same effects as the classical antidepressants such as Monoamine Oxidase Inhibitors (MAOIs), Tricyclic Antidepressants (TCAs), or Selective Serotonin Reuptake Inhibitors (SSRIs). While it has comparable effectiveness to typical first-line options for the treatment of depression such as SSRIs, bupropion is a unique option for the treatment of MDD as it lacks any clinically relevant serotonergic effects, typical of other mood medications, or any effects on histamine or adrenaline receptors. Lack of activity at these receptors results in a more tolerable side effect profile; bupropion is less likely to cause sexual side effects, sedation, or weight gain as compared to SSRIs or TCAs, for example. When used as an aid to smoking cessation, bupropion is thought to confer its anti-craving and anti-withdrawal effects by inhibiting dopamine reuptake, which is thought to be involved in the reward pathways associated with nicotine, and through the antagonism of the nicotinic acetylcholinergic receptor (AChR), thereby blunting the effects of nicotine. Furthermore, the stimulatory effects produced by bupropion in the central nervous system are similar to nicotine's effects, making low doses of bupropion a suitable option as a nicotine substitute. When used in combination with naltrexone in the marketed product ContraveⓇ for chronic weight management, the two components are thought to have effects on areas of the brain involved in the regulation of food intake. This includes the hypothalamus, which is involved in appetite regulation, and the mesolimbic dopamine circuit, which is involved in reward pathways. Studies have shown that the combined activity of bupropion and naltrexone increase the firing rate of hypothalamic pro-opiomelanocortin (POMC) neurons and blockade of opioid receptor-mediated POMC auto-inhibition, which are associated with a reduction in food intake and increased energy expenditure. This combination was also found to reduce food intake when injected directly into the ventral tegmental area of the mesolimbic circuit in mice, which is an area associated with the regulation of reward pathways. •Mechanism of action (Drug B): The exact mechanism through which oxcarbazepine and its active metaoblite, MHD, exert their anti-epileptic effects is unclear, but is thought to primarily involve the blockade of voltage-gated sodium channels. The opening and closing of sodium channels allows for the propagation of action potentials along neurons - in epilepsy, these action potentials can occur in excess of that required for normal function, and the repetitive and pathological firing of these action potentials leads to seizure activity. Both oxcarbazepine and MHD are thought to inhibit seizure activity by binding to the inactive state of voltage-gated sodium channels, thus prolonging the period in which the receptor is unavailable for action potential propagation. This helps to stabilize hyperexcited neuronal membranes, inhibit repetitive neuron firing, and prevent the spread of seizure activity within the CNS without affecting normal neuronal transmission. Increased potassium conductance and modulation of voltage-activated calcium channels is also thought to play a role in the anti-seizure activity of oxcarbazepine. Inhibition of glutamatergic activity was thought to contribute to oxcarbazepine's activity, but this effect could not be replicated in vivo. •Absorption (Drug A): Bupropion is currently available in 3 distinct, but bioequivalent formulations: immediate release (IR), sustained-release (SR), and extended-release (XL). Immediate Release Formulation In humans, following oral administration of bupropion hydrochloride tablets, peak plasma bupropion concentrations are usually achieved within 2 hours. IR formulations provide a short duration of action and are therefore generally dosed three times per day. Sustained Release Formulation In humans, following oral administration of bupropion hydrochloride sustained-release tablets (SR), peak plasma concentration (Cmax) of bupropion is usually achieved within 3 hours. SR formulations provide a 12-hour extended release of medication and are therefore generally dosed twice per day. Extended Release Formulation Following single oral administration of bupropion hydrochloride extended-release tablets (XL) to healthy volunteers, the median time to peak plasma concentrations for bupropion was approximately 5 hours. The presence of food did not affect the peak concentration or area under the curve of bupropion. XL formulations provide a 24-hour extended release of medication and are therefore generally dosed once per day/ In a trial comparing chronic dosing with bupropion hydrochloride extended-release tablets (SR) 150 mg twice daily to bupropion immediate-release formulation 100 mg 3 times daily, the steady state Cmax for bupropion after bupropion hydrochloride sustained-release tablets (SR) administration was approximately 85% of those achieved after bupropion immediate-release formulation administration. Exposure (AUC) to bupropion was equivalent for both formulations. Bioequivalence was also demonstrated for all three major active metabolites (i.e., hydroxybupropion, threohydrobupropion and erythrohydrobupropion) for both Cmax and AUC. Thus, at steady state, bupropion hydrochloride sustained-release tablets (SR) given twice daily, and the immediate-release formulation of bupropion given 3 times daily, are essentially bioequivalent for both bupropion and the 3 quantitatively important metabolites. Furthermore, in a study comparing 14-day dosing with bupropion hydrochloride extended-release tablets (XL), 300 mg once-daily to the immediate-release formulation of bupropion at 100 mg 3 times daily, equivalence was demonstrated for peak plasma concentration and area under the curve for bupropion and the three metabolites (hydroxybupropion, threohydrobupropion, and erythrohydrobupropion). Additionally, in a study comparing 14-day dosing with bupropion hydrochloride extended-release tablets (XL) 300 mg once daily to the sustained-release formulation of bupropion at 150 mg 2 times daily, equivalence was demonstrated for peak plasma concentration and area under the curve for bupropion and the three metabolites. Bupropion hydrochloride extended-release tablets (SR) can be taken with or without food. Bupropion Cmax and AUC were increased by 11% to 35% and 16% to 19%, respectively, when bupropion hydrochloride extended-release tablets (SR) was administered with food to healthy volunteers in three trials. The food effect is not considered clinically significant. Following a single-dose administration of bupropion hydrochloride extended-release tablets (SR) in humans, Cmax of bupropion's metabolite hydroxybupropion occurs approximately 6 hours post-dose and is approximately 10 times the peak level of the parent drug at steady state. The elimination half-life of hydroxybupropion is approximately 20 (±5) hours and its AUC at steady state is about 17 times that of bupropion. The times to peak concentrations for the erythrohydrobupropion and threohydrobupropion metabolites are similar to that of the hydroxybupropion metabolite. However, their elimination half-lives are longer, 33(±10) and 37 (±13) hours, respectively, and steady-state AUCs are 1.5 and 7 times that of bupropion, respectively. •Absorption (Drug B): Oxcarbazepine is completely absorbed following oral administration. A single 600mg dose of oxcarbazepine resulted in an MHD C max of 34 μmol/L and a median T max of 4.5 hours. When administered twice daily, steady-state levels of MHD are attained within 2-3 days. The rate and extent of absorption of oxcarbazepine is not affected by food intake. •Volume of distribution (Drug A): No volume of distribution available •Volume of distribution (Drug B): The apparent volume of distribution of oxcarbazepine is 49 L. The apparent volumes of distribution of (S)- and (R)-MHD were found to be 23.6 L and 31.7 L, respectively. •Protein binding (Drug A): In vitro tests show that bupropion is 84% bound to human plasma proteins at concentrations up to 200 mcg per mL. The extent of protein binding of the hydroxybupropion metabolite is similar to that for bupropion, whereas the extent of protein binding of the threohydrobupropion metabolite is about half that seen with bupropion. •Protein binding (Drug B): The pharmacologically active metabolite of oxcarbazepine, MHD, is approximately 40% bound to plasma proteins, predominantly albumin. •Metabolism (Drug A): Bupropion is extensively metabolized in humans. Three metabolites are active: hydroxybupropion, which is formed via hydroxylation of the tert-butyl group of bupropion, and the amino-alcohol isomers, threohydrobupropion and erythrohydrobupropion, which are formed via reduction of the carbonyl group. In vitro findings suggest that CYP2B6 is the principal isoenzyme involved in the formation of hydroxybupropion, while cytochrome P450 enzymes are not involved in the formation of threohydrobupropion. Hydroxybupropion has been shown to have the same affinity as bupropion for the norepinephrine transporter (NET) but approximately 50% of its antidepressant activity despite reaching concentrations of ~10-fold higher than that of the parent drug. Oxidation of the bupropion side chain results in the formation of a glycine conjugate of meta-chlorobenzoic acid, which is then excreted as the major urinary metabolite. The potency and toxicity of the metabolites relative to bupropion have not been fully characterized. However, it has been demonstrated in an antidepressant screening test in mice that hydroxybupropion is one-half as potent as bupropion, while threohydrobupropion and erythrohydrobupropion are 5-fold less potent than bupropion. This may be of clinical importance because the plasma concentrations of the metabolites are as high as or higher than those of bupropion. Bupropion and its metabolites exhibit linear kinetics following chronic administration of 300 to 450 mg per day. •Metabolism (Drug B): Oxcarbazepine is rapidly and extensively metabolized to its primary metabolite, MHD, which is responsible for the bulk of its anti-epileptic activity and exists in much higher concentrations in the plasma than the parent drug. MHD is formed via reduction by several members of the aldo-keto reductase family of cytosolic liver enzymes and exists as a racemate in plasma in an approximate ratio of 80% (S)-MHD to 20% (R)-MHD. MHD is further metabolized to glucuronide conjugate metabolites for excretion, and small amounts are oxidized to 10-,11-dihydro-10,11-dihydroxycarbamazepine (DHD) which is pharmacologically inactive. Only 10% of an administered dose of oxcarbazepine will remain as either the parent drug or glucuronide conjugates of the parent drug. •Route of elimination (Drug A): Bupropion is extensively metabolized in humans. Oxidation of the bupropion side chain results in the formation of a glycine conjugate of metachlorobenzoic acid, which is then excreted as the major urinary metabolite. Following oral administration of 200 mg of 14C-bupropion in humans, 87% and 10% of the radioactive dose were recovered in the urine and feces, respectively. However, the fraction of the oral dose of bupropion excreted unchanged was only 0.5%, a finding consistent with the extensive metabolism of bupropion. •Route of elimination (Drug B): Following oral administration, more than 95% of the administered dose of oxcarbazepine is found in the urine. Of this, approximately 49% is MHD glucuronide metabolites, 27% is unchanged MHD, 3% is inactive DHD metabolites, 13% is conjugated oxcarbazepine, and less than 1% is unchanged parent drug. Fecal elimination accounts for only 4% of the administered dose. •Half-life (Drug A): 24 hours •Half-life (Drug B): The plasma half-life of oxcarbazepine is approximately 2 hours and the plasma half-life of MHD is approximately 9 hours. •Clearance (Drug A): No clearance available •Clearance (Drug B): Plasma clearance of oxcarbazepine has been estimated to be approximately 84.9 L/h, whereas plasma clearance of its active metabolite, MHD, was estimated to be 2.0 L/h. Rapid metabolic clearance appears to be the main pathway for oxcarbazepine, while clearance of its metabolites occurs mainly via renal excretion. •Toxicity (Drug A): Symptoms of overdose include seizures, hallucinations, loss of consciousness, tachycardia, and cardiac arrest. •Toxicity (Drug B): The oral LD 50 of oxcarbazepine in mammals is 1240 mg/kg and the oral TDLo in children has been reported to be 73 mg/kg. Isolated cases of oxcarbazepine overdose have been reported - patients who ingested up to 24,000mg recovered with symptomatic treatment. Symptoms may include respiratory and CNS depression, movement-related disorders (e.g. dyskinesia, ataxia), nausea/vomiting, hyponatremia, or QTc prolongation. There is no antidote for oxcarbazepine overdose - management should consist of supportive and symptomatic treatment, and consideration should be given to the use of gastric lavage or activated charcoal. •Brand Names (Drug A): Aplenzin, Auvelity, Budeprion, Contrave, Forfivo, Wellbutrin, Zyban •Brand Names (Drug B): Oxtellar, Trileptal •Synonyms (Drug A): No synonyms listed •Synonyms (Drug B): OCBZ Oxcarbamazepine Oxcarbazepina Oxcarbazepine Oxcarbazepinum •Summary (Drug A): Bupropion is a norepinephrine and dopamine reuptake inhibitor used in the treatment of major depressive disorder (MDD), seasonal affective disorder (SAD), and as an aid to smoking cessation. •Summary (Drug B): Oxcarbazepine is an anti-epileptic used in the treatment of partial-onset seizures.

Central nervous system (CNS) depressants can cause sedation, falls, respiratory depression, coma, and death.2,3 The potential interaction between a CNS depressant and another CNS depressant drug due to synergistic effects is well documented in the literature, although the risk and severity of CNS depression vary from each drug. The subject and affected drugs are both CNS depressants that, when co-administered, may result in a more profound CNS depression. As the risk and severity of CNS depression resulting from the combined use of CNS depressants vary from each agent, each interaction between CNS depressants should be considered individually. The severity of the interaction is moderate.

Question: Does Bupropion and Oxcarbazepine interact? Information: •Drug A: Bupropion •Drug B: Oxcarbazepine •Severity: MODERATE •Description: The risk or severity of CNS depression can be increased when Oxcarbazepine is combined with Bupropion. •Extended Description: Central nervous system (CNS) depressants can cause sedation, falls, respiratory depression, coma, and death.2,3 The potential interaction between a CNS depressant and another CNS depressant drug due to synergistic effects is well documented in the literature, although the risk and severity of CNS depression vary from each drug. The subject and affected drugs are both CNS depressants that, when co-administered, may result in a more profound CNS depression. As the risk and severity of CNS depression resulting from the combined use of CNS depressants vary from each agent, each interaction between CNS depressants should be considered individually. •Indication (Drug A): Bupropion is indicated for the treatment of major depressive disorder (MDD), seasonal affective disorder (SAD), and as an aid to smoking cessation. When used in combination with naltrexone as the marketed product ContraveⓇ, bupropion is indicated as an adjunct to a reduced-calorie diet and increased physical activity for chronic weight management in adults with an initial body mass index (BMI) of: 30 kg/m^2 or greater (obese) or 27 kg/m^2 or greater (overweight) in the presence of at least one weight-related comorbid condition (e.g., hypertension, type 2 diabetes mellitus, or dyslipidemia). Bupropion is also used off-label as a first-line treatment in patients with ADHD and comorbid bipolar disorder when used as an adjunct to mood stabilizers. •Indication (Drug B): In the United States, oxcarbazepine is indicated for use as monotherapy or adjunctive therapy in the treatment of partial-onset seizures in adults and as monotherapy in the treatment of partial-onset seizures in pediatric patients aged 4 years and above, and as adjunctive therapy in pediatric patients aged 2 years and above with partial-onset seizures. In Canada, oxcarbazepine is indicated for use as monotherapy or adjunctive therapy in the treatment of partial-onset seizures in patients 6 years of age and older. •Pharmacodynamics (Drug A): Bupropion is chemically unrelated to tricyclic, tetracyclic, selective serotonin re-uptake inhibitors, or other known antidepressant agents. Compared to classical tricyclic antidepressants, Bupropion is a relatively weak inhibitor of the neuronal uptake of norepinephrine and dopamine. In addition, Bupropion does not inhibit monoamine oxidase. Bupropion has been found to be essentially inactive at the serotonin transporter (SERT)(IC50 >10 000 nM), however both bupropion and its primary metabolite hydroxybupropion have been found to block the function of cation-selective serotonin type 3A receptors (5-HT3ARs). Bupropion produces dose-related central nervous system (CNS) stimulant effects in animals, as evidenced by increased locomotor activity, increased rates of responding in various schedule-controlled operant behaviour tasks, and, at high doses, induction of mild stereotyped behaviour. Due to these stimulant effects and selective activity at dopamine and norepinephrine receptors, bupropion has been identified as having an abuse potential. Bupropion has a similar structure to the controlled substance Cathinone, and has been identified as having mild amphetamine-like activity, particularly when inhaled or injected. Bupropion is also known to lower the seizure threshold, making any pre-existing seizure conditions a contraindication to its use. This risk is exacerbated when bupropion is combined with other drugs or substances that lower the seizure threshold, such as cocaine, or in clinical situations that would increase the risk of a seizure such as abrupt alcohol or benzodiazepine withdrawal. As norepinephrine has been shown to have anticonvulsant properties, bupropion's inhibitory effects on NET are thought to contribute to its pro-convulsant activity. Bupropion has been shown to increase blood pressure and pose a risk for exacerbation of unmanaged or pre-existing hypertension, however, clinical trials of bupropion in smokers with CVD have not identified an increased incidence of CV events including stroke or heart attack. In clinical trials, the mean increase in systolic blood pressure associated with the use of bupropion was found to be 1.3 mmHg. •Pharmacodynamics (Drug B): Oxcarbazepine is an anticonvulsant drug that reduces the incidence of seizures in epilepsy by inhibiting abnormal electrical activity in the brain. There have been rare reports of oxcarbazepine resulting in the development of hematologic abnormalities, including agranulocytosis and aplastic anemia. Patients should be undergo frequent laboratory testing and should be monitored closely for signs and symptoms of blood dyscrasias. Oxcarbazepine has also been associated with the development of dermatologic reactions which can progress from a simple rash to potentially fatal reactions such as toxic epidermal necrolysis (TEN) or Stevens-Johnson Syndrome (SJS). Patients with the HLA-A 3101 and/or HLA-B 1502 alleles may be at higher risk of this reaction. Oxcarbazepine should be discontinued at the first sign of a drug-induced skin reaction. •Mechanism of action (Drug A): Bupropion is a norepinephrine/dopamine-reuptake inhibitor (NDRI) that exerts its pharmacological effects by weakly inhibiting the enzymes involved in the uptake of the neurotransmitters norepinephrine and dopamine from the synaptic cleft, therefore prolonging their duration of action within the neuronal synapse and the downstream effects of these neurotransmitters. More specifically, bupropion binds to the norepinephrine transporter (NET) and the dopamine transporter (DAT). Bupropion was originally classified as an "atypical" antidepressant because it does not exert the same effects as the classical antidepressants such as Monoamine Oxidase Inhibitors (MAOIs), Tricyclic Antidepressants (TCAs), or Selective Serotonin Reuptake Inhibitors (SSRIs). While it has comparable effectiveness to typical first-line options for the treatment of depression such as SSRIs, bupropion is a unique option for the treatment of MDD as it lacks any clinically relevant serotonergic effects, typical of other mood medications, or any effects on histamine or adrenaline receptors. Lack of activity at these receptors results in a more tolerable side effect profile; bupropion is less likely to cause sexual side effects, sedation, or weight gain as compared to SSRIs or TCAs, for example. When used as an aid to smoking cessation, bupropion is thought to confer its anti-craving and anti-withdrawal effects by inhibiting dopamine reuptake, which is thought to be involved in the reward pathways associated with nicotine, and through the antagonism of the nicotinic acetylcholinergic receptor (AChR), thereby blunting the effects of nicotine. Furthermore, the stimulatory effects produced by bupropion in the central nervous system are similar to nicotine's effects, making low doses of bupropion a suitable option as a nicotine substitute. When used in combination with naltrexone in the marketed product ContraveⓇ for chronic weight management, the two components are thought to have effects on areas of the brain involved in the regulation of food intake. This includes the hypothalamus, which is involved in appetite regulation, and the mesolimbic dopamine circuit, which is involved in reward pathways. Studies have shown that the combined activity of bupropion and naltrexone increase the firing rate of hypothalamic pro-opiomelanocortin (POMC) neurons and blockade of opioid receptor-mediated POMC auto-inhibition, which are associated with a reduction in food intake and increased energy expenditure. This combination was also found to reduce food intake when injected directly into the ventral tegmental area of the mesolimbic circuit in mice, which is an area associated with the regulation of reward pathways. •Mechanism of action (Drug B): The exact mechanism through which oxcarbazepine and its active metaoblite, MHD, exert their anti-epileptic effects is unclear, but is thought to primarily involve the blockade of voltage-gated sodium channels. The opening and closing of sodium channels allows for the propagation of action potentials along neurons - in epilepsy, these action potentials can occur in excess of that required for normal function, and the repetitive and pathological firing of these action potentials leads to seizure activity. Both oxcarbazepine and MHD are thought to inhibit seizure activity by binding to the inactive state of voltage-gated sodium channels, thus prolonging the period in which the receptor is unavailable for action potential propagation. This helps to stabilize hyperexcited neuronal membranes, inhibit repetitive neuron firing, and prevent the spread of seizure activity within the CNS without affecting normal neuronal transmission. Increased potassium conductance and modulation of voltage-activated calcium channels is also thought to play a role in the anti-seizure activity of oxcarbazepine. Inhibition of glutamatergic activity was thought to contribute to oxcarbazepine's activity, but this effect could not be replicated in vivo. •Absorption (Drug A): Bupropion is currently available in 3 distinct, but bioequivalent formulations: immediate release (IR), sustained-release (SR), and extended-release (XL). Immediate Release Formulation In humans, following oral administration of bupropion hydrochloride tablets, peak plasma bupropion concentrations are usually achieved within 2 hours. IR formulations provide a short duration of action and are therefore generally dosed three times per day. Sustained Release Formulation In humans, following oral administration of bupropion hydrochloride sustained-release tablets (SR), peak plasma concentration (Cmax) of bupropion is usually achieved within 3 hours. SR formulations provide a 12-hour extended release of medication and are therefore generally dosed twice per day. Extended Release Formulation Following single oral administration of bupropion hydrochloride extended-release tablets (XL) to healthy volunteers, the median time to peak plasma concentrations for bupropion was approximately 5 hours. The presence of food did not affect the peak concentration or area under the curve of bupropion. XL formulations provide a 24-hour extended release of medication and are therefore generally dosed once per day/ In a trial comparing chronic dosing with bupropion hydrochloride extended-release tablets (SR) 150 mg twice daily to bupropion immediate-release formulation 100 mg 3 times daily, the steady state Cmax for bupropion after bupropion hydrochloride sustained-release tablets (SR) administration was approximately 85% of those achieved after bupropion immediate-release formulation administration. Exposure (AUC) to bupropion was equivalent for both formulations. Bioequivalence was also demonstrated for all three major active metabolites (i.e., hydroxybupropion, threohydrobupropion and erythrohydrobupropion) for both Cmax and AUC. Thus, at steady state, bupropion hydrochloride sustained-release tablets (SR) given twice daily, and the immediate-release formulation of bupropion given 3 times daily, are essentially bioequivalent for both bupropion and the 3 quantitatively important metabolites. Furthermore, in a study comparing 14-day dosing with bupropion hydrochloride extended-release tablets (XL), 300 mg once-daily to the immediate-release formulation of bupropion at 100 mg 3 times daily, equivalence was demonstrated for peak plasma concentration and area under the curve for bupropion and the three metabolites (hydroxybupropion, threohydrobupropion, and erythrohydrobupropion). Additionally, in a study comparing 14-day dosing with bupropion hydrochloride extended-release tablets (XL) 300 mg once daily to the sustained-release formulation of bupropion at 150 mg 2 times daily, equivalence was demonstrated for peak plasma concentration and area under the curve for bupropion and the three metabolites. Bupropion hydrochloride extended-release tablets (SR) can be taken with or without food. Bupropion Cmax and AUC were increased by 11% to 35% and 16% to 19%, respectively, when bupropion hydrochloride extended-release tablets (SR) was administered with food to healthy volunteers in three trials. The food effect is not considered clinically significant. Following a single-dose administration of bupropion hydrochloride extended-release tablets (SR) in humans, Cmax of bupropion's metabolite hydroxybupropion occurs approximately 6 hours post-dose and is approximately 10 times the peak level of the parent drug at steady state. The elimination half-life of hydroxybupropion is approximately 20 (±5) hours and its AUC at steady state is about 17 times that of bupropion. The times to peak concentrations for the erythrohydrobupropion and threohydrobupropion metabolites are similar to that of the hydroxybupropion metabolite. However, their elimination half-lives are longer, 33(±10) and 37 (±13) hours, respectively, and steady-state AUCs are 1.5 and 7 times that of bupropion, respectively. •Absorption (Drug B): Oxcarbazepine is completely absorbed following oral administration. A single 600mg dose of oxcarbazepine resulted in an MHD C max of 34 μmol/L and a median T max of 4.5 hours. When administered twice daily, steady-state levels of MHD are attained within 2-3 days. The rate and extent of absorption of oxcarbazepine is not affected by food intake. •Volume of distribution (Drug A): No volume of distribution available •Volume of distribution (Drug B): The apparent volume of distribution of oxcarbazepine is 49 L. The apparent volumes of distribution of (S)- and (R)-MHD were found to be 23.6 L and 31.7 L, respectively. •Protein binding (Drug A): In vitro tests show that bupropion is 84% bound to human plasma proteins at concentrations up to 200 mcg per mL. The extent of protein binding of the hydroxybupropion metabolite is similar to that for bupropion, whereas the extent of protein binding of the threohydrobupropion metabolite is about half that seen with bupropion. •Protein binding (Drug B): The pharmacologically active metabolite of oxcarbazepine, MHD, is approximately 40% bound to plasma proteins, predominantly albumin. •Metabolism (Drug A): Bupropion is extensively metabolized in humans. Three metabolites are active: hydroxybupropion, which is formed via hydroxylation of the tert-butyl group of bupropion, and the amino-alcohol isomers, threohydrobupropion and erythrohydrobupropion, which are formed via reduction of the carbonyl group. In vitro findings suggest that CYP2B6 is the principal isoenzyme involved in the formation of hydroxybupropion, while cytochrome P450 enzymes are not involved in the formation of threohydrobupropion. Hydroxybupropion has been shown to have the same affinity as bupropion for the norepinephrine transporter (NET) but approximately 50% of its antidepressant activity despite reaching concentrations of ~10-fold higher than that of the parent drug. Oxidation of the bupropion side chain results in the formation of a glycine conjugate of meta-chlorobenzoic acid, which is then excreted as the major urinary metabolite. The potency and toxicity of the metabolites relative to bupropion have not been fully characterized. However, it has been demonstrated in an antidepressant screening test in mice that hydroxybupropion is one-half as potent as bupropion, while threohydrobupropion and erythrohydrobupropion are 5-fold less potent than bupropion. This may be of clinical importance because the plasma concentrations of the metabolites are as high as or higher than those of bupropion. Bupropion and its metabolites exhibit linear kinetics following chronic administration of 300 to 450 mg per day. •Metabolism (Drug B): Oxcarbazepine is rapidly and extensively metabolized to its primary metabolite, MHD, which is responsible for the bulk of its anti-epileptic activity and exists in much higher concentrations in the plasma than the parent drug. MHD is formed via reduction by several members of the aldo-keto reductase family of cytosolic liver enzymes and exists as a racemate in plasma in an approximate ratio of 80% (S)-MHD to 20% (R)-MHD. MHD is further metabolized to glucuronide conjugate metabolites for excretion, and small amounts are oxidized to 10-,11-dihydro-10,11-dihydroxycarbamazepine (DHD) which is pharmacologically inactive. Only 10% of an administered dose of oxcarbazepine will remain as either the parent drug or glucuronide conjugates of the parent drug. •Route of elimination (Drug A): Bupropion is extensively metabolized in humans. Oxidation of the bupropion side chain results in the formation of a glycine conjugate of metachlorobenzoic acid, which is then excreted as the major urinary metabolite. Following oral administration of 200 mg of 14C-bupropion in humans, 87% and 10% of the radioactive dose were recovered in the urine and feces, respectively. However, the fraction of the oral dose of bupropion excreted unchanged was only 0.5%, a finding consistent with the extensive metabolism of bupropion. •Route of elimination (Drug B): Following oral administration, more than 95% of the administered dose of oxcarbazepine is found in the urine. Of this, approximately 49% is MHD glucuronide metabolites, 27% is unchanged MHD, 3% is inactive DHD metabolites, 13% is conjugated oxcarbazepine, and less than 1% is unchanged parent drug. Fecal elimination accounts for only 4% of the administered dose. •Half-life (Drug A): 24 hours •Half-life (Drug B): The plasma half-life of oxcarbazepine is approximately 2 hours and the plasma half-life of MHD is approximately 9 hours. •Clearance (Drug A): No clearance available •Clearance (Drug B): Plasma clearance of oxcarbazepine has been estimated to be approximately 84.9 L/h, whereas plasma clearance of its active metabolite, MHD, was estimated to be 2.0 L/h. Rapid metabolic clearance appears to be the main pathway for oxcarbazepine, while clearance of its metabolites occurs mainly via renal excretion. •Toxicity (Drug A): Symptoms of overdose include seizures, hallucinations, loss of consciousness, tachycardia, and cardiac arrest. •Toxicity (Drug B): The oral LD 50 of oxcarbazepine in mammals is 1240 mg/kg and the oral TDLo in children has been reported to be 73 mg/kg. Isolated cases of oxcarbazepine overdose have been reported - patients who ingested up to 24,000mg recovered with symptomatic treatment. Symptoms may include respiratory and CNS depression, movement-related disorders (e.g. dyskinesia, ataxia), nausea/vomiting, hyponatremia, or QTc prolongation. There is no antidote for oxcarbazepine overdose - management should consist of supportive and symptomatic treatment, and consideration should be given to the use of gastric lavage or activated charcoal. •Brand Names (Drug A): Aplenzin, Auvelity, Budeprion, Contrave, Forfivo, Wellbutrin, Zyban •Brand Names (Drug B): Oxtellar, Trileptal •Synonyms (Drug A): No synonyms listed •Synonyms (Drug B): OCBZ Oxcarbamazepine Oxcarbazepina Oxcarbazepine Oxcarbazepinum •Summary (Drug A): Bupropion is a norepinephrine and dopamine reuptake inhibitor used in the treatment of major depressive disorder (MDD), seasonal affective disorder (SAD), and as an aid to smoking cessation. •Summary (Drug B): Oxcarbazepine is an anti-epileptic used in the treatment of partial-onset seizures. Output: Central nervous system (CNS) depressants can cause sedation, falls, respiratory depression, coma, and death.2,3 The potential interaction between a CNS depressant and another CNS depressant drug due to synergistic effects is well documented in the literature, although the risk and severity of CNS depression vary from each drug. The subject and affected drugs are both CNS depressants that, when co-administered, may result in a more profound CNS depression. As the risk and severity of CNS depression resulting from the combined use of CNS depressants vary from each agent, each interaction between CNS depressants should be considered individually. The severity of the interaction is moderate.

Does Bupropion and Oxitriptan interact?

•Drug A: Bupropion •Drug B: Oxitriptan •Severity: MODERATE •Description: The risk or severity of CNS depression can be increased when Bupropion is combined with Oxitriptan. •Extended Description: Central nervous system (CNS) depressants can cause sedation, falls, respiratory depression, coma, and death.2,3 The potential interaction between a CNS depressant and another CNS depressant drug due to synergistic effects is well documented in the literature, although the risk and severity of CNS depression vary from each drug. The subject and affected drugs are both CNS depressants that, when co-administered, may result in a more profound CNS depression. As the risk and severity of CNS depression resulting from the combined use of CNS depressants vary from each agent, each interaction between CNS depressants should be considered individually. •Indication (Drug A): Bupropion is indicated for the treatment of major depressive disorder (MDD), seasonal affective disorder (SAD), and as an aid to smoking cessation. When used in combination with naltrexone as the marketed product ContraveⓇ, bupropion is indicated as an adjunct to a reduced-calorie diet and increased physical activity for chronic weight management in adults with an initial body mass index (BMI) of: 30 kg/m^2 or greater (obese) or 27 kg/m^2 or greater (overweight) in the presence of at least one weight-related comorbid condition (e.g., hypertension, type 2 diabetes mellitus, or dyslipidemia). Bupropion is also used off-label as a first-line treatment in patients with ADHD and comorbid bipolar disorder when used as an adjunct to mood stabilizers. •Indication (Drug B): For use as an antidepressant, appetite suppressant, and sleep aid. •Pharmacodynamics (Drug A): Bupropion is chemically unrelated to tricyclic, tetracyclic, selective serotonin re-uptake inhibitors, or other known antidepressant agents. Compared to classical tricyclic antidepressants, Bupropion is a relatively weak inhibitor of the neuronal uptake of norepinephrine and dopamine. In addition, Bupropion does not inhibit monoamine oxidase. Bupropion has been found to be essentially inactive at the serotonin transporter (SERT)(IC50 >10 000 nM), however both bupropion and its primary metabolite hydroxybupropion have been found to block the function of cation-selective serotonin type 3A receptors (5-HT3ARs). Bupropion produces dose-related central nervous system (CNS) stimulant effects in animals, as evidenced by increased locomotor activity, increased rates of responding in various schedule-controlled operant behaviour tasks, and, at high doses, induction of mild stereotyped behaviour. Due to these stimulant effects and selective activity at dopamine and norepinephrine receptors, bupropion has been identified as having an abuse potential. Bupropion has a similar structure to the controlled substance Cathinone, and has been identified as having mild amphetamine-like activity, particularly when inhaled or injected. Bupropion is also known to lower the seizure threshold, making any pre-existing seizure conditions a contraindication to its use. This risk is exacerbated when bupropion is combined with other drugs or substances that lower the seizure threshold, such as cocaine, or in clinical situations that would increase the risk of a seizure such as abrupt alcohol or benzodiazepine withdrawal. As norepinephrine has been shown to have anticonvulsant properties, bupropion's inhibitory effects on NET are thought to contribute to its pro-convulsant activity. Bupropion has been shown to increase blood pressure and pose a risk for exacerbation of unmanaged or pre-existing hypertension, however, clinical trials of bupropion in smokers with CVD have not identified an increased incidence of CV events including stroke or heart attack. In clinical trials, the mean increase in systolic blood pressure associated with the use of bupropion was found to be 1.3 mmHg. •Pharmacodynamics (Drug B): The psychoactive action of 5-HTP is thought to be due to increased serotonin production in central nervous system tissue. •Mechanism of action (Drug A): Bupropion is a norepinephrine/dopamine-reuptake inhibitor (NDRI) that exerts its pharmacological effects by weakly inhibiting the enzymes involved in the uptake of the neurotransmitters norepinephrine and dopamine from the synaptic cleft, therefore prolonging their duration of action within the neuronal synapse and the downstream effects of these neurotransmitters. More specifically, bupropion binds to the norepinephrine transporter (NET) and the dopamine transporter (DAT). Bupropion was originally classified as an "atypical" antidepressant because it does not exert the same effects as the classical antidepressants such as Monoamine Oxidase Inhibitors (MAOIs), Tricyclic Antidepressants (TCAs), or Selective Serotonin Reuptake Inhibitors (SSRIs). While it has comparable effectiveness to typical first-line options for the treatment of depression such as SSRIs, bupropion is a unique option for the treatment of MDD as it lacks any clinically relevant serotonergic effects, typical of other mood medications, or any effects on histamine or adrenaline receptors. Lack of activity at these receptors results in a more tolerable side effect profile; bupropion is less likely to cause sexual side effects, sedation, or weight gain as compared to SSRIs or TCAs, for example. When used as an aid to smoking cessation, bupropion is thought to confer its anti-craving and anti-withdrawal effects by inhibiting dopamine reuptake, which is thought to be involved in the reward pathways associated with nicotine, and through the antagonism of the nicotinic acetylcholinergic receptor (AChR), thereby blunting the effects of nicotine. Furthermore, the stimulatory effects produced by bupropion in the central nervous system are similar to nicotine's effects, making low doses of bupropion a suitable option as a nicotine substitute. When used in combination with naltrexone in the marketed product ContraveⓇ for chronic weight management, the two components are thought to have effects on areas of the brain involved in the regulation of food intake. This includes the hypothalamus, which is involved in appetite regulation, and the mesolimbic dopamine circuit, which is involved in reward pathways. Studies have shown that the combined activity of bupropion and naltrexone increase the firing rate of hypothalamic pro-opiomelanocortin (POMC) neurons and blockade of opioid receptor-mediated POMC auto-inhibition, which are associated with a reduction in food intake and increased energy expenditure. This combination was also found to reduce food intake when injected directly into the ventral tegmental area of the mesolimbic circuit in mice, which is an area associated with the regulation of reward pathways. •Mechanism of action (Drug B): No mechanism of action available •Absorption (Drug A): Bupropion is currently available in 3 distinct, but bioequivalent formulations: immediate release (IR), sustained-release (SR), and extended-release (XL). Immediate Release Formulation In humans, following oral administration of bupropion hydrochloride tablets, peak plasma bupropion concentrations are usually achieved within 2 hours. IR formulations provide a short duration of action and are therefore generally dosed three times per day. Sustained Release Formulation In humans, following oral administration of bupropion hydrochloride sustained-release tablets (SR), peak plasma concentration (Cmax) of bupropion is usually achieved within 3 hours. SR formulations provide a 12-hour extended release of medication and are therefore generally dosed twice per day. Extended Release Formulation Following single oral administration of bupropion hydrochloride extended-release tablets (XL) to healthy volunteers, the median time to peak plasma concentrations for bupropion was approximately 5 hours. The presence of food did not affect the peak concentration or area under the curve of bupropion. XL formulations provide a 24-hour extended release of medication and are therefore generally dosed once per day/ In a trial comparing chronic dosing with bupropion hydrochloride extended-release tablets (SR) 150 mg twice daily to bupropion immediate-release formulation 100 mg 3 times daily, the steady state Cmax for bupropion after bupropion hydrochloride sustained-release tablets (SR) administration was approximately 85% of those achieved after bupropion immediate-release formulation administration. Exposure (AUC) to bupropion was equivalent for both formulations. Bioequivalence was also demonstrated for all three major active metabolites (i.e., hydroxybupropion, threohydrobupropion and erythrohydrobupropion) for both Cmax and AUC. Thus, at steady state, bupropion hydrochloride sustained-release tablets (SR) given twice daily, and the immediate-release formulation of bupropion given 3 times daily, are essentially bioequivalent for both bupropion and the 3 quantitatively important metabolites. Furthermore, in a study comparing 14-day dosing with bupropion hydrochloride extended-release tablets (XL), 300 mg once-daily to the immediate-release formulation of bupropion at 100 mg 3 times daily, equivalence was demonstrated for peak plasma concentration and area under the curve for bupropion and the three metabolites (hydroxybupropion, threohydrobupropion, and erythrohydrobupropion). Additionally, in a study comparing 14-day dosing with bupropion hydrochloride extended-release tablets (XL) 300 mg once daily to the sustained-release formulation of bupropion at 150 mg 2 times daily, equivalence was demonstrated for peak plasma concentration and area under the curve for bupropion and the three metabolites. Bupropion hydrochloride extended-release tablets (SR) can be taken with or without food. Bupropion Cmax and AUC were increased by 11% to 35% and 16% to 19%, respectively, when bupropion hydrochloride extended-release tablets (SR) was administered with food to healthy volunteers in three trials. The food effect is not considered clinically significant. Following a single-dose administration of bupropion hydrochloride extended-release tablets (SR) in humans, Cmax of bupropion's metabolite hydroxybupropion occurs approximately 6 hours post-dose and is approximately 10 times the peak level of the parent drug at steady state. The elimination half-life of hydroxybupropion is approximately 20 (±5) hours and its AUC at steady state is about 17 times that of bupropion. The times to peak concentrations for the erythrohydrobupropion and threohydrobupropion metabolites are similar to that of the hydroxybupropion metabolite. However, their elimination half-lives are longer, 33(±10) and 37 (±13) hours, respectively, and steady-state AUCs are 1.5 and 7 times that of bupropion, respectively. •Absorption (Drug B): No absorption available •Volume of distribution (Drug A): No volume of distribution available •Volume of distribution (Drug B): No volume of distribution available •Protein binding (Drug A): In vitro tests show that bupropion is 84% bound to human plasma proteins at concentrations up to 200 mcg per mL. The extent of protein binding of the hydroxybupropion metabolite is similar to that for bupropion, whereas the extent of protein binding of the threohydrobupropion metabolite is about half that seen with bupropion. •Protein binding (Drug B): No protein binding available •Metabolism (Drug A): Bupropion is extensively metabolized in humans. Three metabolites are active: hydroxybupropion, which is formed via hydroxylation of the tert-butyl group of bupropion, and the amino-alcohol isomers, threohydrobupropion and erythrohydrobupropion, which are formed via reduction of the carbonyl group. In vitro findings suggest that CYP2B6 is the principal isoenzyme involved in the formation of hydroxybupropion, while cytochrome P450 enzymes are not involved in the formation of threohydrobupropion. Hydroxybupropion has been shown to have the same affinity as bupropion for the norepinephrine transporter (NET) but approximately 50% of its antidepressant activity despite reaching concentrations of ~10-fold higher than that of the parent drug. Oxidation of the bupropion side chain results in the formation of a glycine conjugate of meta-chlorobenzoic acid, which is then excreted as the major urinary metabolite. The potency and toxicity of the metabolites relative to bupropion have not been fully characterized. However, it has been demonstrated in an antidepressant screening test in mice that hydroxybupropion is one-half as potent as bupropion, while threohydrobupropion and erythrohydrobupropion are 5-fold less potent than bupropion. This may be of clinical importance because the plasma concentrations of the metabolites are as high as or higher than those of bupropion. Bupropion and its metabolites exhibit linear kinetics following chronic administration of 300 to 450 mg per day. •Metabolism (Drug B): 5-Hydroxytryptophan is decarboxylated to serotonin (5-hydroxytryptamine or 5-HT) by the enzyme aromatic-L-amino-acid decarboxylase via a vitamin B6 dependent reaction in nervous tissue and in the liver. •Route of elimination (Drug A): Bupropion is extensively metabolized in humans. Oxidation of the bupropion side chain results in the formation of a glycine conjugate of metachlorobenzoic acid, which is then excreted as the major urinary metabolite. Following oral administration of 200 mg of 14C-bupropion in humans, 87% and 10% of the radioactive dose were recovered in the urine and feces, respectively. However, the fraction of the oral dose of bupropion excreted unchanged was only 0.5%, a finding consistent with the extensive metabolism of bupropion. •Route of elimination (Drug B): No route of elimination available •Half-life (Drug A): 24 hours •Half-life (Drug B): No half-life available •Clearance (Drug A): No clearance available •Clearance (Drug B): No clearance available •Toxicity (Drug A): Symptoms of overdose include seizures, hallucinations, loss of consciousness, tachycardia, and cardiac arrest. •Toxicity (Drug B): No toxicity available •Brand Names (Drug A): Aplenzin, Auvelity, Budeprion, Contrave, Forfivo, Wellbutrin, Zyban •Brand Names (Drug B): No brand names available •Synonyms (Drug A): No synonyms listed •Synonyms (Drug B): L-5 Hydroxytrytophan Oxitriptan Oxitriptano Oxitriptanum •Summary (Drug A): Bupropion is a norepinephrine and dopamine reuptake inhibitor used in the treatment of major depressive disorder (MDD), seasonal affective disorder (SAD), and as an aid to smoking cessation. •Summary (Drug B): Oxitriptan is a naturally occurring amino acid that is used to manage post-hypoxic myoclonus.

Central nervous system (CNS) depressants can cause sedation, falls, respiratory depression, coma, and death.2,3 The potential interaction between a CNS depressant and another CNS depressant drug due to synergistic effects is well documented in the literature, although the risk and severity of CNS depression vary from each drug. The subject and affected drugs are both CNS depressants that, when co-administered, may result in a more profound CNS depression. As the risk and severity of CNS depression resulting from the combined use of CNS depressants vary from each agent, each interaction between CNS depressants should be considered individually. The severity of the interaction is moderate.

Question: Does Bupropion and Oxitriptan interact? Information: •Drug A: Bupropion •Drug B: Oxitriptan •Severity: MODERATE •Description: The risk or severity of CNS depression can be increased when Bupropion is combined with Oxitriptan. •Extended Description: Central nervous system (CNS) depressants can cause sedation, falls, respiratory depression, coma, and death.2,3 The potential interaction between a CNS depressant and another CNS depressant drug due to synergistic effects is well documented in the literature, although the risk and severity of CNS depression vary from each drug. The subject and affected drugs are both CNS depressants that, when co-administered, may result in a more profound CNS depression. As the risk and severity of CNS depression resulting from the combined use of CNS depressants vary from each agent, each interaction between CNS depressants should be considered individually. •Indication (Drug A): Bupropion is indicated for the treatment of major depressive disorder (MDD), seasonal affective disorder (SAD), and as an aid to smoking cessation. When used in combination with naltrexone as the marketed product ContraveⓇ, bupropion is indicated as an adjunct to a reduced-calorie diet and increased physical activity for chronic weight management in adults with an initial body mass index (BMI) of: 30 kg/m^2 or greater (obese) or 27 kg/m^2 or greater (overweight) in the presence of at least one weight-related comorbid condition (e.g., hypertension, type 2 diabetes mellitus, or dyslipidemia). Bupropion is also used off-label as a first-line treatment in patients with ADHD and comorbid bipolar disorder when used as an adjunct to mood stabilizers. •Indication (Drug B): For use as an antidepressant, appetite suppressant, and sleep aid. •Pharmacodynamics (Drug A): Bupropion is chemically unrelated to tricyclic, tetracyclic, selective serotonin re-uptake inhibitors, or other known antidepressant agents. Compared to classical tricyclic antidepressants, Bupropion is a relatively weak inhibitor of the neuronal uptake of norepinephrine and dopamine. In addition, Bupropion does not inhibit monoamine oxidase. Bupropion has been found to be essentially inactive at the serotonin transporter (SERT)(IC50 >10 000 nM), however both bupropion and its primary metabolite hydroxybupropion have been found to block the function of cation-selective serotonin type 3A receptors (5-HT3ARs). Bupropion produces dose-related central nervous system (CNS) stimulant effects in animals, as evidenced by increased locomotor activity, increased rates of responding in various schedule-controlled operant behaviour tasks, and, at high doses, induction of mild stereotyped behaviour. Due to these stimulant effects and selective activity at dopamine and norepinephrine receptors, bupropion has been identified as having an abuse potential. Bupropion has a similar structure to the controlled substance Cathinone, and has been identified as having mild amphetamine-like activity, particularly when inhaled or injected. Bupropion is also known to lower the seizure threshold, making any pre-existing seizure conditions a contraindication to its use. This risk is exacerbated when bupropion is combined with other drugs or substances that lower the seizure threshold, such as cocaine, or in clinical situations that would increase the risk of a seizure such as abrupt alcohol or benzodiazepine withdrawal. As norepinephrine has been shown to have anticonvulsant properties, bupropion's inhibitory effects on NET are thought to contribute to its pro-convulsant activity. Bupropion has been shown to increase blood pressure and pose a risk for exacerbation of unmanaged or pre-existing hypertension, however, clinical trials of bupropion in smokers with CVD have not identified an increased incidence of CV events including stroke or heart attack. In clinical trials, the mean increase in systolic blood pressure associated with the use of bupropion was found to be 1.3 mmHg. •Pharmacodynamics (Drug B): The psychoactive action of 5-HTP is thought to be due to increased serotonin production in central nervous system tissue. •Mechanism of action (Drug A): Bupropion is a norepinephrine/dopamine-reuptake inhibitor (NDRI) that exerts its pharmacological effects by weakly inhibiting the enzymes involved in the uptake of the neurotransmitters norepinephrine and dopamine from the synaptic cleft, therefore prolonging their duration of action within the neuronal synapse and the downstream effects of these neurotransmitters. More specifically, bupropion binds to the norepinephrine transporter (NET) and the dopamine transporter (DAT). Bupropion was originally classified as an "atypical" antidepressant because it does not exert the same effects as the classical antidepressants such as Monoamine Oxidase Inhibitors (MAOIs), Tricyclic Antidepressants (TCAs), or Selective Serotonin Reuptake Inhibitors (SSRIs). While it has comparable effectiveness to typical first-line options for the treatment of depression such as SSRIs, bupropion is a unique option for the treatment of MDD as it lacks any clinically relevant serotonergic effects, typical of other mood medications, or any effects on histamine or adrenaline receptors. Lack of activity at these receptors results in a more tolerable side effect profile; bupropion is less likely to cause sexual side effects, sedation, or weight gain as compared to SSRIs or TCAs, for example. When used as an aid to smoking cessation, bupropion is thought to confer its anti-craving and anti-withdrawal effects by inhibiting dopamine reuptake, which is thought to be involved in the reward pathways associated with nicotine, and through the antagonism of the nicotinic acetylcholinergic receptor (AChR), thereby blunting the effects of nicotine. Furthermore, the stimulatory effects produced by bupropion in the central nervous system are similar to nicotine's effects, making low doses of bupropion a suitable option as a nicotine substitute. When used in combination with naltrexone in the marketed product ContraveⓇ for chronic weight management, the two components are thought to have effects on areas of the brain involved in the regulation of food intake. This includes the hypothalamus, which is involved in appetite regulation, and the mesolimbic dopamine circuit, which is involved in reward pathways. Studies have shown that the combined activity of bupropion and naltrexone increase the firing rate of hypothalamic pro-opiomelanocortin (POMC) neurons and blockade of opioid receptor-mediated POMC auto-inhibition, which are associated with a reduction in food intake and increased energy expenditure. This combination was also found to reduce food intake when injected directly into the ventral tegmental area of the mesolimbic circuit in mice, which is an area associated with the regulation of reward pathways. •Mechanism of action (Drug B): No mechanism of action available •Absorption (Drug A): Bupropion is currently available in 3 distinct, but bioequivalent formulations: immediate release (IR), sustained-release (SR), and extended-release (XL). Immediate Release Formulation In humans, following oral administration of bupropion hydrochloride tablets, peak plasma bupropion concentrations are usually achieved within 2 hours. IR formulations provide a short duration of action and are therefore generally dosed three times per day. Sustained Release Formulation In humans, following oral administration of bupropion hydrochloride sustained-release tablets (SR), peak plasma concentration (Cmax) of bupropion is usually achieved within 3 hours. SR formulations provide a 12-hour extended release of medication and are therefore generally dosed twice per day. Extended Release Formulation Following single oral administration of bupropion hydrochloride extended-release tablets (XL) to healthy volunteers, the median time to peak plasma concentrations for bupropion was approximately 5 hours. The presence of food did not affect the peak concentration or area under the curve of bupropion. XL formulations provide a 24-hour extended release of medication and are therefore generally dosed once per day/ In a trial comparing chronic dosing with bupropion hydrochloride extended-release tablets (SR) 150 mg twice daily to bupropion immediate-release formulation 100 mg 3 times daily, the steady state Cmax for bupropion after bupropion hydrochloride sustained-release tablets (SR) administration was approximately 85% of those achieved after bupropion immediate-release formulation administration. Exposure (AUC) to bupropion was equivalent for both formulations. Bioequivalence was also demonstrated for all three major active metabolites (i.e., hydroxybupropion, threohydrobupropion and erythrohydrobupropion) for both Cmax and AUC. Thus, at steady state, bupropion hydrochloride sustained-release tablets (SR) given twice daily, and the immediate-release formulation of bupropion given 3 times daily, are essentially bioequivalent for both bupropion and the 3 quantitatively important metabolites. Furthermore, in a study comparing 14-day dosing with bupropion hydrochloride extended-release tablets (XL), 300 mg once-daily to the immediate-release formulation of bupropion at 100 mg 3 times daily, equivalence was demonstrated for peak plasma concentration and area under the curve for bupropion and the three metabolites (hydroxybupropion, threohydrobupropion, and erythrohydrobupropion). Additionally, in a study comparing 14-day dosing with bupropion hydrochloride extended-release tablets (XL) 300 mg once daily to the sustained-release formulation of bupropion at 150 mg 2 times daily, equivalence was demonstrated for peak plasma concentration and area under the curve for bupropion and the three metabolites. Bupropion hydrochloride extended-release tablets (SR) can be taken with or without food. Bupropion Cmax and AUC were increased by 11% to 35% and 16% to 19%, respectively, when bupropion hydrochloride extended-release tablets (SR) was administered with food to healthy volunteers in three trials. The food effect is not considered clinically significant. Following a single-dose administration of bupropion hydrochloride extended-release tablets (SR) in humans, Cmax of bupropion's metabolite hydroxybupropion occurs approximately 6 hours post-dose and is approximately 10 times the peak level of the parent drug at steady state. The elimination half-life of hydroxybupropion is approximately 20 (±5) hours and its AUC at steady state is about 17 times that of bupropion. The times to peak concentrations for the erythrohydrobupropion and threohydrobupropion metabolites are similar to that of the hydroxybupropion metabolite. However, their elimination half-lives are longer, 33(±10) and 37 (±13) hours, respectively, and steady-state AUCs are 1.5 and 7 times that of bupropion, respectively. •Absorption (Drug B): No absorption available •Volume of distribution (Drug A): No volume of distribution available •Volume of distribution (Drug B): No volume of distribution available •Protein binding (Drug A): In vitro tests show that bupropion is 84% bound to human plasma proteins at concentrations up to 200 mcg per mL. The extent of protein binding of the hydroxybupropion metabolite is similar to that for bupropion, whereas the extent of protein binding of the threohydrobupropion metabolite is about half that seen with bupropion. •Protein binding (Drug B): No protein binding available •Metabolism (Drug A): Bupropion is extensively metabolized in humans. Three metabolites are active: hydroxybupropion, which is formed via hydroxylation of the tert-butyl group of bupropion, and the amino-alcohol isomers, threohydrobupropion and erythrohydrobupropion, which are formed via reduction of the carbonyl group. In vitro findings suggest that CYP2B6 is the principal isoenzyme involved in the formation of hydroxybupropion, while cytochrome P450 enzymes are not involved in the formation of threohydrobupropion. Hydroxybupropion has been shown to have the same affinity as bupropion for the norepinephrine transporter (NET) but approximately 50% of its antidepressant activity despite reaching concentrations of ~10-fold higher than that of the parent drug. Oxidation of the bupropion side chain results in the formation of a glycine conjugate of meta-chlorobenzoic acid, which is then excreted as the major urinary metabolite. The potency and toxicity of the metabolites relative to bupropion have not been fully characterized. However, it has been demonstrated in an antidepressant screening test in mice that hydroxybupropion is one-half as potent as bupropion, while threohydrobupropion and erythrohydrobupropion are 5-fold less potent than bupropion. This may be of clinical importance because the plasma concentrations of the metabolites are as high as or higher than those of bupropion. Bupropion and its metabolites exhibit linear kinetics following chronic administration of 300 to 450 mg per day. •Metabolism (Drug B): 5-Hydroxytryptophan is decarboxylated to serotonin (5-hydroxytryptamine or 5-HT) by the enzyme aromatic-L-amino-acid decarboxylase via a vitamin B6 dependent reaction in nervous tissue and in the liver. •Route of elimination (Drug A): Bupropion is extensively metabolized in humans. Oxidation of the bupropion side chain results in the formation of a glycine conjugate of metachlorobenzoic acid, which is then excreted as the major urinary metabolite. Following oral administration of 200 mg of 14C-bupropion in humans, 87% and 10% of the radioactive dose were recovered in the urine and feces, respectively. However, the fraction of the oral dose of bupropion excreted unchanged was only 0.5%, a finding consistent with the extensive metabolism of bupropion. •Route of elimination (Drug B): No route of elimination available •Half-life (Drug A): 24 hours •Half-life (Drug B): No half-life available •Clearance (Drug A): No clearance available •Clearance (Drug B): No clearance available •Toxicity (Drug A): Symptoms of overdose include seizures, hallucinations, loss of consciousness, tachycardia, and cardiac arrest. •Toxicity (Drug B): No toxicity available •Brand Names (Drug A): Aplenzin, Auvelity, Budeprion, Contrave, Forfivo, Wellbutrin, Zyban •Brand Names (Drug B): No brand names available •Synonyms (Drug A): No synonyms listed •Synonyms (Drug B): L-5 Hydroxytrytophan Oxitriptan Oxitriptano Oxitriptanum •Summary (Drug A): Bupropion is a norepinephrine and dopamine reuptake inhibitor used in the treatment of major depressive disorder (MDD), seasonal affective disorder (SAD), and as an aid to smoking cessation. •Summary (Drug B): Oxitriptan is a naturally occurring amino acid that is used to manage post-hypoxic myoclonus. Output: Central nervous system (CNS) depressants can cause sedation, falls, respiratory depression, coma, and death.2,3 The potential interaction between a CNS depressant and another CNS depressant drug due to synergistic effects is well documented in the literature, although the risk and severity of CNS depression vary from each drug. The subject and affected drugs are both CNS depressants that, when co-administered, may result in a more profound CNS depression. As the risk and severity of CNS depression resulting from the combined use of CNS depressants vary from each agent, each interaction between CNS depressants should be considered individually. The severity of the interaction is moderate.

Does Bupropion and Oxybenzone interact?

•Drug A: Bupropion •Drug B: Oxybenzone •Severity: MINOR •Description: Bupropion may decrease the excretion rate of Oxybenzone which could result in a higher serum level. •Extended Description: The renal excretion of drugs is the overall result of a combination of kidney processes that include glomerular filtration, passive diffusion, tubular secretion, and tubular reabsorption. Since two of these mechanisms - tubular secretion and reabsorption - are saturable processes , they are consequently susceptible to competition between multiple substrates excreted by the kidneys. If two or more medications that are mainly renally excreted are co-administered, they may compete for renal elimination; there is a large likelihood that one agent may "out-compete" or saturate the renal excretion mechanisms before the other concomitantly administered agent(s) are excreted. As a result, the elimination of these other concurrently administered agents may be inhibited or otherwise delayed, which could lead to increases in their serum concentrations and the risk, incidence, and/or severity of adverse effects associated with the exposure to such drugs. •Indication (Drug A): Bupropion is indicated for the treatment of major depressive disorder (MDD), seasonal affective disorder (SAD), and as an aid to smoking cessation. When used in combination with naltrexone as the marketed product ContraveⓇ, bupropion is indicated as an adjunct to a reduced-calorie diet and increased physical activity for chronic weight management in adults with an initial body mass index (BMI) of: 30 kg/m^2 or greater (obese) or 27 kg/m^2 or greater (overweight) in the presence of at least one weight-related comorbid condition (e.g., hypertension, type 2 diabetes mellitus, or dyslipidemia). Bupropion is also used off-label as a first-line treatment in patients with ADHD and comorbid bipolar disorder when used as an adjunct to mood stabilizers. •Indication (Drug B): Used as an ingredient in sunscreen and other cosmetics. •Pharmacodynamics (Drug A): Bupropion is chemically unrelated to tricyclic, tetracyclic, selective serotonin re-uptake inhibitors, or other known antidepressant agents. Compared to classical tricyclic antidepressants, Bupropion is a relatively weak inhibitor of the neuronal uptake of norepinephrine and dopamine. In addition, Bupropion does not inhibit monoamine oxidase. Bupropion has been found to be essentially inactive at the serotonin transporter (SERT)(IC50 >10 000 nM), however both bupropion and its primary metabolite hydroxybupropion have been found to block the function of cation-selective serotonin type 3A receptors (5-HT3ARs). Bupropion produces dose-related central nervous system (CNS) stimulant effects in animals, as evidenced by increased locomotor activity, increased rates of responding in various schedule-controlled operant behaviour tasks, and, at high doses, induction of mild stereotyped behaviour. Due to these stimulant effects and selective activity at dopamine and norepinephrine receptors, bupropion has been identified as having an abuse potential. Bupropion has a similar structure to the controlled substance Cathinone, and has been identified as having mild amphetamine-like activity, particularly when inhaled or injected. Bupropion is also known to lower the seizure threshold, making any pre-existing seizure conditions a contraindication to its use. This risk is exacerbated when bupropion is combined with other drugs or substances that lower the seizure threshold, such as cocaine, or in clinical situations that would increase the risk of a seizure such as abrupt alcohol or benzodiazepine withdrawal. As norepinephrine has been shown to have anticonvulsant properties, bupropion's inhibitory effects on NET are thought to contribute to its pro-convulsant activity. Bupropion has been shown to increase blood pressure and pose a risk for exacerbation of unmanaged or pre-existing hypertension, however, clinical trials of bupropion in smokers with CVD have not identified an increased incidence of CV events including stroke or heart attack. In clinical trials, the mean increase in systolic blood pressure associated with the use of bupropion was found to be 1.3 mmHg. •Pharmacodynamics (Drug B): Oxybenzone is an organic compound used in sunscreens. It is a derivative of benzophenone. •Mechanism of action (Drug A): Bupropion is a norepinephrine/dopamine-reuptake inhibitor (NDRI) that exerts its pharmacological effects by weakly inhibiting the enzymes involved in the uptake of the neurotransmitters norepinephrine and dopamine from the synaptic cleft, therefore prolonging their duration of action within the neuronal synapse and the downstream effects of these neurotransmitters. More specifically, bupropion binds to the norepinephrine transporter (NET) and the dopamine transporter (DAT). Bupropion was originally classified as an "atypical" antidepressant because it does not exert the same effects as the classical antidepressants such as Monoamine Oxidase Inhibitors (MAOIs), Tricyclic Antidepressants (TCAs), or Selective Serotonin Reuptake Inhibitors (SSRIs). While it has comparable effectiveness to typical first-line options for the treatment of depression such as SSRIs, bupropion is a unique option for the treatment of MDD as it lacks any clinically relevant serotonergic effects, typical of other mood medications, or any effects on histamine or adrenaline receptors. Lack of activity at these receptors results in a more tolerable side effect profile; bupropion is less likely to cause sexual side effects, sedation, or weight gain as compared to SSRIs or TCAs, for example. When used as an aid to smoking cessation, bupropion is thought to confer its anti-craving and anti-withdrawal effects by inhibiting dopamine reuptake, which is thought to be involved in the reward pathways associated with nicotine, and through the antagonism of the nicotinic acetylcholinergic receptor (AChR), thereby blunting the effects of nicotine. Furthermore, the stimulatory effects produced by bupropion in the central nervous system are similar to nicotine's effects, making low doses of bupropion a suitable option as a nicotine substitute. When used in combination with naltrexone in the marketed product ContraveⓇ for chronic weight management, the two components are thought to have effects on areas of the brain involved in the regulation of food intake. This includes the hypothalamus, which is involved in appetite regulation, and the mesolimbic dopamine circuit, which is involved in reward pathways. Studies have shown that the combined activity of bupropion and naltrexone increase the firing rate of hypothalamic pro-opiomelanocortin (POMC) neurons and blockade of opioid receptor-mediated POMC auto-inhibition, which are associated with a reduction in food intake and increased energy expenditure. This combination was also found to reduce food intake when injected directly into the ventral tegmental area of the mesolimbic circuit in mice, which is an area associated with the regulation of reward pathways. •Mechanism of action (Drug B): Oxybenzone absorbs UV-A ultraviolet rays, preventing them from reaching the skin. •Absorption (Drug A): Bupropion is currently available in 3 distinct, but bioequivalent formulations: immediate release (IR), sustained-release (SR), and extended-release (XL). Immediate Release Formulation In humans, following oral administration of bupropion hydrochloride tablets, peak plasma bupropion concentrations are usually achieved within 2 hours. IR formulations provide a short duration of action and are therefore generally dosed three times per day. Sustained Release Formulation In humans, following oral administration of bupropion hydrochloride sustained-release tablets (SR), peak plasma concentration (Cmax) of bupropion is usually achieved within 3 hours. SR formulations provide a 12-hour extended release of medication and are therefore generally dosed twice per day. Extended Release Formulation Following single oral administration of bupropion hydrochloride extended-release tablets (XL) to healthy volunteers, the median time to peak plasma concentrations for bupropion was approximately 5 hours. The presence of food did not affect the peak concentration or area under the curve of bupropion. XL formulations provide a 24-hour extended release of medication and are therefore generally dosed once per day/ In a trial comparing chronic dosing with bupropion hydrochloride extended-release tablets (SR) 150 mg twice daily to bupropion immediate-release formulation 100 mg 3 times daily, the steady state Cmax for bupropion after bupropion hydrochloride sustained-release tablets (SR) administration was approximately 85% of those achieved after bupropion immediate-release formulation administration. Exposure (AUC) to bupropion was equivalent for both formulations. Bioequivalence was also demonstrated for all three major active metabolites (i.e., hydroxybupropion, threohydrobupropion and erythrohydrobupropion) for both Cmax and AUC. Thus, at steady state, bupropion hydrochloride sustained-release tablets (SR) given twice daily, and the immediate-release formulation of bupropion given 3 times daily, are essentially bioequivalent for both bupropion and the 3 quantitatively important metabolites. Furthermore, in a study comparing 14-day dosing with bupropion hydrochloride extended-release tablets (XL), 300 mg once-daily to the immediate-release formulation of bupropion at 100 mg 3 times daily, equivalence was demonstrated for peak plasma concentration and area under the curve for bupropion and the three metabolites (hydroxybupropion, threohydrobupropion, and erythrohydrobupropion). Additionally, in a study comparing 14-day dosing with bupropion hydrochloride extended-release tablets (XL) 300 mg once daily to the sustained-release formulation of bupropion at 150 mg 2 times daily, equivalence was demonstrated for peak plasma concentration and area under the curve for bupropion and the three metabolites. Bupropion hydrochloride extended-release tablets (SR) can be taken with or without food. Bupropion Cmax and AUC were increased by 11% to 35% and 16% to 19%, respectively, when bupropion hydrochloride extended-release tablets (SR) was administered with food to healthy volunteers in three trials. The food effect is not considered clinically significant. Following a single-dose administration of bupropion hydrochloride extended-release tablets (SR) in humans, Cmax of bupropion's metabolite hydroxybupropion occurs approximately 6 hours post-dose and is approximately 10 times the peak level of the parent drug at steady state. The elimination half-life of hydroxybupropion is approximately 20 (±5) hours and its AUC at steady state is about 17 times that of bupropion. The times to peak concentrations for the erythrohydrobupropion and threohydrobupropion metabolites are similar to that of the hydroxybupropion metabolite. However, their elimination half-lives are longer, 33(±10) and 37 (±13) hours, respectively, and steady-state AUCs are 1.5 and 7 times that of bupropion, respectively. •Absorption (Drug B): No absorption available •Volume of distribution (Drug A): No volume of distribution available •Volume of distribution (Drug B): No volume of distribution available •Protein binding (Drug A): In vitro tests show that bupropion is 84% bound to human plasma proteins at concentrations up to 200 mcg per mL. The extent of protein binding of the hydroxybupropion metabolite is similar to that for bupropion, whereas the extent of protein binding of the threohydrobupropion metabolite is about half that seen with bupropion. •Protein binding (Drug B): No protein binding available •Metabolism (Drug A): Bupropion is extensively metabolized in humans. Three metabolites are active: hydroxybupropion, which is formed via hydroxylation of the tert-butyl group of bupropion, and the amino-alcohol isomers, threohydrobupropion and erythrohydrobupropion, which are formed via reduction of the carbonyl group. In vitro findings suggest that CYP2B6 is the principal isoenzyme involved in the formation of hydroxybupropion, while cytochrome P450 enzymes are not involved in the formation of threohydrobupropion. Hydroxybupropion has been shown to have the same affinity as bupropion for the norepinephrine transporter (NET) but approximately 50% of its antidepressant activity despite reaching concentrations of ~10-fold higher than that of the parent drug. Oxidation of the bupropion side chain results in the formation of a glycine conjugate of meta-chlorobenzoic acid, which is then excreted as the major urinary metabolite. The potency and toxicity of the metabolites relative to bupropion have not been fully characterized. However, it has been demonstrated in an antidepressant screening test in mice that hydroxybupropion is one-half as potent as bupropion, while threohydrobupropion and erythrohydrobupropion are 5-fold less potent than bupropion. This may be of clinical importance because the plasma concentrations of the metabolites are as high as or higher than those of bupropion. Bupropion and its metabolites exhibit linear kinetics following chronic administration of 300 to 450 mg per day. •Metabolism (Drug B): No metabolism available •Route of elimination (Drug A): Bupropion is extensively metabolized in humans. Oxidation of the bupropion side chain results in the formation of a glycine conjugate of metachlorobenzoic acid, which is then excreted as the major urinary metabolite. Following oral administration of 200 mg of 14C-bupropion in humans, 87% and 10% of the radioactive dose were recovered in the urine and feces, respectively. However, the fraction of the oral dose of bupropion excreted unchanged was only 0.5%, a finding consistent with the extensive metabolism of bupropion. •Route of elimination (Drug B): In vivo studies show oxybenzone is abosorbed transdermally (through the skin) and is excreted in the urine. •Half-life (Drug A): 24 hours •Half-life (Drug B): No half-life available •Clearance (Drug A): No clearance available •Clearance (Drug B): No clearance available •Toxicity (Drug A): Symptoms of overdose include seizures, hallucinations, loss of consciousness, tachycardia, and cardiac arrest. •Toxicity (Drug B): No toxicity available •Brand Names (Drug A): Aplenzin, Auvelity, Budeprion, Contrave, Forfivo, Wellbutrin, Zyban •Brand Names (Drug B): Meijer •Synonyms (Drug A): No synonyms listed •Synonyms (Drug B): Oxibenzona Oxybenzone Oxybenzonum •Summary (Drug A): Bupropion is a norepinephrine and dopamine reuptake inhibitor used in the treatment of major depressive disorder (MDD), seasonal affective disorder (SAD), and as an aid to smoking cessation. •Summary (Drug B): Oxybenzone is a sunscreen agent found in sunscreens that absorbs UV rays.

The renal excretion of drugs is the overall result of a combination of kidney processes that include glomerular filtration, passive diffusion, tubular secretion, and tubular reabsorption. Since two of these mechanisms - tubular secretion and reabsorption - are saturable processes , they are consequently susceptible to competition between multiple substrates excreted by the kidneys. If two or more medications that are mainly renally excreted are co-administered, they may compete for renal elimination; there is a large likelihood that one agent may "out-compete" or saturate the renal excretion mechanisms before the other concomitantly administered agent(s) are excreted. As a result, the elimination of these other concurrently administered agents may be inhibited or otherwise delayed, which could lead to increases in their serum concentrations and the risk, incidence, and/or severity of adverse effects associated with the exposure to such drugs. The severity of the interaction is minor.

Question: Does Bupropion and Oxybenzone interact? Information: •Drug A: Bupropion •Drug B: Oxybenzone •Severity: MINOR •Description: Bupropion may decrease the excretion rate of Oxybenzone which could result in a higher serum level. •Extended Description: The renal excretion of drugs is the overall result of a combination of kidney processes that include glomerular filtration, passive diffusion, tubular secretion, and tubular reabsorption. Since two of these mechanisms - tubular secretion and reabsorption - are saturable processes , they are consequently susceptible to competition between multiple substrates excreted by the kidneys. If two or more medications that are mainly renally excreted are co-administered, they may compete for renal elimination; there is a large likelihood that one agent may "out-compete" or saturate the renal excretion mechanisms before the other concomitantly administered agent(s) are excreted. As a result, the elimination of these other concurrently administered agents may be inhibited or otherwise delayed, which could lead to increases in their serum concentrations and the risk, incidence, and/or severity of adverse effects associated with the exposure to such drugs. •Indication (Drug A): Bupropion is indicated for the treatment of major depressive disorder (MDD), seasonal affective disorder (SAD), and as an aid to smoking cessation. When used in combination with naltrexone as the marketed product ContraveⓇ, bupropion is indicated as an adjunct to a reduced-calorie diet and increased physical activity for chronic weight management in adults with an initial body mass index (BMI) of: 30 kg/m^2 or greater (obese) or 27 kg/m^2 or greater (overweight) in the presence of at least one weight-related comorbid condition (e.g., hypertension, type 2 diabetes mellitus, or dyslipidemia). Bupropion is also used off-label as a first-line treatment in patients with ADHD and comorbid bipolar disorder when used as an adjunct to mood stabilizers. •Indication (Drug B): Used as an ingredient in sunscreen and other cosmetics. •Pharmacodynamics (Drug A): Bupropion is chemically unrelated to tricyclic, tetracyclic, selective serotonin re-uptake inhibitors, or other known antidepressant agents. Compared to classical tricyclic antidepressants, Bupropion is a relatively weak inhibitor of the neuronal uptake of norepinephrine and dopamine. In addition, Bupropion does not inhibit monoamine oxidase. Bupropion has been found to be essentially inactive at the serotonin transporter (SERT)(IC50 >10 000 nM), however both bupropion and its primary metabolite hydroxybupropion have been found to block the function of cation-selective serotonin type 3A receptors (5-HT3ARs). Bupropion produces dose-related central nervous system (CNS) stimulant effects in animals, as evidenced by increased locomotor activity, increased rates of responding in various schedule-controlled operant behaviour tasks, and, at high doses, induction of mild stereotyped behaviour. Due to these stimulant effects and selective activity at dopamine and norepinephrine receptors, bupropion has been identified as having an abuse potential. Bupropion has a similar structure to the controlled substance Cathinone, and has been identified as having mild amphetamine-like activity, particularly when inhaled or injected. Bupropion is also known to lower the seizure threshold, making any pre-existing seizure conditions a contraindication to its use. This risk is exacerbated when bupropion is combined with other drugs or substances that lower the seizure threshold, such as cocaine, or in clinical situations that would increase the risk of a seizure such as abrupt alcohol or benzodiazepine withdrawal. As norepinephrine has been shown to have anticonvulsant properties, bupropion's inhibitory effects on NET are thought to contribute to its pro-convulsant activity. Bupropion has been shown to increase blood pressure and pose a risk for exacerbation of unmanaged or pre-existing hypertension, however, clinical trials of bupropion in smokers with CVD have not identified an increased incidence of CV events including stroke or heart attack. In clinical trials, the mean increase in systolic blood pressure associated with the use of bupropion was found to be 1.3 mmHg. •Pharmacodynamics (Drug B): Oxybenzone is an organic compound used in sunscreens. It is a derivative of benzophenone. •Mechanism of action (Drug A): Bupropion is a norepinephrine/dopamine-reuptake inhibitor (NDRI) that exerts its pharmacological effects by weakly inhibiting the enzymes involved in the uptake of the neurotransmitters norepinephrine and dopamine from the synaptic cleft, therefore prolonging their duration of action within the neuronal synapse and the downstream effects of these neurotransmitters. More specifically, bupropion binds to the norepinephrine transporter (NET) and the dopamine transporter (DAT). Bupropion was originally classified as an "atypical" antidepressant because it does not exert the same effects as the classical antidepressants such as Monoamine Oxidase Inhibitors (MAOIs), Tricyclic Antidepressants (TCAs), or Selective Serotonin Reuptake Inhibitors (SSRIs). While it has comparable effectiveness to typical first-line options for the treatment of depression such as SSRIs, bupropion is a unique option for the treatment of MDD as it lacks any clinically relevant serotonergic effects, typical of other mood medications, or any effects on histamine or adrenaline receptors. Lack of activity at these receptors results in a more tolerable side effect profile; bupropion is less likely to cause sexual side effects, sedation, or weight gain as compared to SSRIs or TCAs, for example. When used as an aid to smoking cessation, bupropion is thought to confer its anti-craving and anti-withdrawal effects by inhibiting dopamine reuptake, which is thought to be involved in the reward pathways associated with nicotine, and through the antagonism of the nicotinic acetylcholinergic receptor (AChR), thereby blunting the effects of nicotine. Furthermore, the stimulatory effects produced by bupropion in the central nervous system are similar to nicotine's effects, making low doses of bupropion a suitable option as a nicotine substitute. When used in combination with naltrexone in the marketed product ContraveⓇ for chronic weight management, the two components are thought to have effects on areas of the brain involved in the regulation of food intake. This includes the hypothalamus, which is involved in appetite regulation, and the mesolimbic dopamine circuit, which is involved in reward pathways. Studies have shown that the combined activity of bupropion and naltrexone increase the firing rate of hypothalamic pro-opiomelanocortin (POMC) neurons and blockade of opioid receptor-mediated POMC auto-inhibition, which are associated with a reduction in food intake and increased energy expenditure. This combination was also found to reduce food intake when injected directly into the ventral tegmental area of the mesolimbic circuit in mice, which is an area associated with the regulation of reward pathways. •Mechanism of action (Drug B): Oxybenzone absorbs UV-A ultraviolet rays, preventing them from reaching the skin. •Absorption (Drug A): Bupropion is currently available in 3 distinct, but bioequivalent formulations: immediate release (IR), sustained-release (SR), and extended-release (XL). Immediate Release Formulation In humans, following oral administration of bupropion hydrochloride tablets, peak plasma bupropion concentrations are usually achieved within 2 hours. IR formulations provide a short duration of action and are therefore generally dosed three times per day. Sustained Release Formulation In humans, following oral administration of bupropion hydrochloride sustained-release tablets (SR), peak plasma concentration (Cmax) of bupropion is usually achieved within 3 hours. SR formulations provide a 12-hour extended release of medication and are therefore generally dosed twice per day. Extended Release Formulation Following single oral administration of bupropion hydrochloride extended-release tablets (XL) to healthy volunteers, the median time to peak plasma concentrations for bupropion was approximately 5 hours. The presence of food did not affect the peak concentration or area under the curve of bupropion. XL formulations provide a 24-hour extended release of medication and are therefore generally dosed once per day/ In a trial comparing chronic dosing with bupropion hydrochloride extended-release tablets (SR) 150 mg twice daily to bupropion immediate-release formulation 100 mg 3 times daily, the steady state Cmax for bupropion after bupropion hydrochloride sustained-release tablets (SR) administration was approximately 85% of those achieved after bupropion immediate-release formulation administration. Exposure (AUC) to bupropion was equivalent for both formulations. Bioequivalence was also demonstrated for all three major active metabolites (i.e., hydroxybupropion, threohydrobupropion and erythrohydrobupropion) for both Cmax and AUC. Thus, at steady state, bupropion hydrochloride sustained-release tablets (SR) given twice daily, and the immediate-release formulation of bupropion given 3 times daily, are essentially bioequivalent for both bupropion and the 3 quantitatively important metabolites. Furthermore, in a study comparing 14-day dosing with bupropion hydrochloride extended-release tablets (XL), 300 mg once-daily to the immediate-release formulation of bupropion at 100 mg 3 times daily, equivalence was demonstrated for peak plasma concentration and area under the curve for bupropion and the three metabolites (hydroxybupropion, threohydrobupropion, and erythrohydrobupropion). Additionally, in a study comparing 14-day dosing with bupropion hydrochloride extended-release tablets (XL) 300 mg once daily to the sustained-release formulation of bupropion at 150 mg 2 times daily, equivalence was demonstrated for peak plasma concentration and area under the curve for bupropion and the three metabolites. Bupropion hydrochloride extended-release tablets (SR) can be taken with or without food. Bupropion Cmax and AUC were increased by 11% to 35% and 16% to 19%, respectively, when bupropion hydrochloride extended-release tablets (SR) was administered with food to healthy volunteers in three trials. The food effect is not considered clinically significant. Following a single-dose administration of bupropion hydrochloride extended-release tablets (SR) in humans, Cmax of bupropion's metabolite hydroxybupropion occurs approximately 6 hours post-dose and is approximately 10 times the peak level of the parent drug at steady state. The elimination half-life of hydroxybupropion is approximately 20 (±5) hours and its AUC at steady state is about 17 times that of bupropion. The times to peak concentrations for the erythrohydrobupropion and threohydrobupropion metabolites are similar to that of the hydroxybupropion metabolite. However, their elimination half-lives are longer, 33(±10) and 37 (±13) hours, respectively, and steady-state AUCs are 1.5 and 7 times that of bupropion, respectively. •Absorption (Drug B): No absorption available •Volume of distribution (Drug A): No volume of distribution available •Volume of distribution (Drug B): No volume of distribution available •Protein binding (Drug A): In vitro tests show that bupropion is 84% bound to human plasma proteins at concentrations up to 200 mcg per mL. The extent of protein binding of the hydroxybupropion metabolite is similar to that for bupropion, whereas the extent of protein binding of the threohydrobupropion metabolite is about half that seen with bupropion. •Protein binding (Drug B): No protein binding available •Metabolism (Drug A): Bupropion is extensively metabolized in humans. Three metabolites are active: hydroxybupropion, which is formed via hydroxylation of the tert-butyl group of bupropion, and the amino-alcohol isomers, threohydrobupropion and erythrohydrobupropion, which are formed via reduction of the carbonyl group. In vitro findings suggest that CYP2B6 is the principal isoenzyme involved in the formation of hydroxybupropion, while cytochrome P450 enzymes are not involved in the formation of threohydrobupropion. Hydroxybupropion has been shown to have the same affinity as bupropion for the norepinephrine transporter (NET) but approximately 50% of its antidepressant activity despite reaching concentrations of ~10-fold higher than that of the parent drug. Oxidation of the bupropion side chain results in the formation of a glycine conjugate of meta-chlorobenzoic acid, which is then excreted as the major urinary metabolite. The potency and toxicity of the metabolites relative to bupropion have not been fully characterized. However, it has been demonstrated in an antidepressant screening test in mice that hydroxybupropion is one-half as potent as bupropion, while threohydrobupropion and erythrohydrobupropion are 5-fold less potent than bupropion. This may be of clinical importance because the plasma concentrations of the metabolites are as high as or higher than those of bupropion. Bupropion and its metabolites exhibit linear kinetics following chronic administration of 300 to 450 mg per day. •Metabolism (Drug B): No metabolism available •Route of elimination (Drug A): Bupropion is extensively metabolized in humans. Oxidation of the bupropion side chain results in the formation of a glycine conjugate of metachlorobenzoic acid, which is then excreted as the major urinary metabolite. Following oral administration of 200 mg of 14C-bupropion in humans, 87% and 10% of the radioactive dose were recovered in the urine and feces, respectively. However, the fraction of the oral dose of bupropion excreted unchanged was only 0.5%, a finding consistent with the extensive metabolism of bupropion. •Route of elimination (Drug B): In vivo studies show oxybenzone is abosorbed transdermally (through the skin) and is excreted in the urine. •Half-life (Drug A): 24 hours •Half-life (Drug B): No half-life available •Clearance (Drug A): No clearance available •Clearance (Drug B): No clearance available •Toxicity (Drug A): Symptoms of overdose include seizures, hallucinations, loss of consciousness, tachycardia, and cardiac arrest. •Toxicity (Drug B): No toxicity available •Brand Names (Drug A): Aplenzin, Auvelity, Budeprion, Contrave, Forfivo, Wellbutrin, Zyban •Brand Names (Drug B): Meijer •Synonyms (Drug A): No synonyms listed •Synonyms (Drug B): Oxibenzona Oxybenzone Oxybenzonum •Summary (Drug A): Bupropion is a norepinephrine and dopamine reuptake inhibitor used in the treatment of major depressive disorder (MDD), seasonal affective disorder (SAD), and as an aid to smoking cessation. •Summary (Drug B): Oxybenzone is a sunscreen agent found in sunscreens that absorbs UV rays. Output: The renal excretion of drugs is the overall result of a combination of kidney processes that include glomerular filtration, passive diffusion, tubular secretion, and tubular reabsorption. Since two of these mechanisms - tubular secretion and reabsorption - are saturable processes , they are consequently susceptible to competition between multiple substrates excreted by the kidneys. If two or more medications that are mainly renally excreted are co-administered, they may compete for renal elimination; there is a large likelihood that one agent may "out-compete" or saturate the renal excretion mechanisms before the other concomitantly administered agent(s) are excreted. As a result, the elimination of these other concurrently administered agents may be inhibited or otherwise delayed, which could lead to increases in their serum concentrations and the risk, incidence, and/or severity of adverse effects associated with the exposure to such drugs. The severity of the interaction is minor.