Pharmacodynamics Compared to bupropion,<unk>  is similar in its potency as a norepinephrine reuptake inhibitor (IC50 = 1.7 μM), but is substantially weaker as a dopamine reuptake inhibitor (IC50 = >10 μM). Like bupropion,<unk>  is also a non-competitive antagonist of nACh receptors, such as α4β2 and α3β4, but is even more potent in comparison. Pharmacokinetics Bupropion is extensively and rapidly absorbed in the gastrointestinal tract but experiences extensive first pass metabolism rendering its systemic bioavailability limited. Exact bioavailability has yet to be determined given an intravenous form does not exist. Absorption is suggested to be between 80-90%. Its distribution half-life is between 3–4 hours and exhibits moderate human plasma protein binding (between 82–88%) with the parent compound and<unk>  displaying the highest affinity. Bupropion is a racemic mixture and is metabolized hepatically primarily via oxidative cleavage of its side chains by CYP2B6.<unk>  is the most potent of the metabolites. It is formed via the "hydroxylation of the tert-butyl group" by CYP2B6 and is excreted renally. Cmax vales of<unk>  are 4–7 times that of bupropion, while the exposure to<unk>  is "10 fold" that of bupropion.<unk> 's elimination half-life is roughly 20 hours, give or take 5 hours and will reach steady state concentrations within 8 days.
Hydroxybupropion
Entropion
Bupropion
Atomoxetine
Citalopram
Ectropion
Vortioxetine
Fluoxetine