Anesthesia Intravenous<unk>  is often used for anesthesia and to treat pain. To induce anesthesia, it is given with a sedative-hypnotic, like propofol or thiopental, and a muscle relaxant. To maintain anesthesia, inhaled anesthetics and additional<unk>  may be used. These are often given in 15–30 minute intervals throughout procedures such as endoscopy and surgeries and in emergency rooms. For pain relief after surgery, use can decrease the amount of inhalational anesthetic needed for emergence from anesthesia. Balancing this medication and titrating the drug based on expected stimuli and the person's responses can result in stable blood pressure and heart rate throughout a procedure and a faster emergence from anesthesia with minimal pain. Regional anesthesia<unk>  is the most commonly used intrathecal opioid because its lipophilic profile allows a quick onset of action (5–10 min.) and intermediate duration of action (60–120 min.). Spinal administration of hyperbaric bupivacaine with<unk>  may be the optimal combination. The almost immediate onset of<unk>  reduces visceral discomfort and even nausea during the procedure. Obstetrics<unk>  is sometimes given intrathecally as part of spinal anesthesia or epidurally for epidural anaesthesia and analgesia. Because of<unk> 's high lipid solubility, its effects are more localized than morphine, and some clinicians prefer to use morphine to get a wider spread of analgesia. However, it is widely used in obstetrical anesthesia because of its short time to action peak (about 5 min), the rapid termination of its effect after a single dose, and the occurrence of relative cardiovascular stability. In obstetrics, the dose must be closely regulated in order to prevent large amounts of transfer from mother to<unk> tus. At high doses, the drug may act on the<unk> tus to cause postnatal respiratory distress. For this reason, shorter acting agents such as alfentanyl or remifentanil may be more suitable in the context of inducing general anaesthesia. Pain management A<unk>  nasal spray with a strength of 100 μg per use The bioavailability of intranasal<unk>  is about 70–90%, but with some imprecision due to clotted nostrils, pharyngeal swallow, and incorrect administration. For both emergency and palliative use, intranasal<unk>  is available in doses of 50, 100, and 200 µg. In emergency medicine, safe administration of intranasal<unk>  with a low rate of side effects and a promising pain-reducing effect was demonstrated in a prospective observational study in about 900 out-of-hospital patients. In children, intranasal<unk>  is useful for the treatment of moderate and severe pain and is well tolerated. Chronic pain It is also used in the management of chronic pain including cancer pain. Often, transdermal patches are used. The patches work by slowly releasing<unk>  through the skin into the bloodstream over 48 to 72 hours, allowing for long-lasting pain management. Dosage is based on the size of the patch, since, in general, the transdermal absorption rate is constant at a constant skin temperature. Each patch should be changed every 72 hours. Rate of absorption is dependent on a number of factors. Body temperature, skin type, amount of body fat, and placement of the patch can have major effects. The different delivery systems used by different makers will also affect individual rates of absorption. Under normal circumstances, the patch will reach its full effect within 12 to 24 hours; thus,<unk>  patches are often prescribed with a fast-acting opioid (such as morphine or oxycodone) to handle breakthrough pain. It is unclear if<unk>  gives long-term pain relief to people with neuropathic pain. Breakthrough pain Sublingual<unk>  dissolves quickly and is absorbed through the sublingual mucosa to provide rapid analgesia.<unk>  is a highly lipophilic compound, which is well absorbed sublingually and generally well tolerated. Such forms are particularly useful for breakthrough cancer pain episodes, which are often rapid in onset, short in duration, and severe in intensity. Palliative care A<unk>  transdermal patch with a release rate of 12 micrograms per hour, on a person's arm In palliative care, transdermal<unk>  patches have a definitive, but limited role for: * people already stabilized on other opioids who have persistent swallowing problems and cannot tolerate other parenteral routes such as subcutaneous administration. * people with moderate to severe kidney failure. * troublesome side effects of oral morphine, hydromorphone, or oxycodone. When using the transdermal patch, patients must be careful to minimize or avoid external heat sources (direct sunlight, heating pads, etc.), which can trigger the release of too much medication and cause potentially deadly complications. Combat medicine USAF Pararescue combat medics in Afghanistan used<unk>  lozenges in the form of lollipops on combat casualties from IED blasts and other trauma. The stick is taped to a finger and the lozenge put in the cheek of the person. When enough<unk>  has been absorbed, the (sedated) person generally lets the lollipop fall from the mouth, indicating sufficient analgesia and somewhat reducing the likelihood of overdose and associated risks. Dyspnea<unk>  can also be used for patients in which morphine is not tolerated, or whose breathlessness is refractory to morphine.<unk>  is especially useful for concomitant treatment in palliative care settings where pain and shortness of breath are severe and need to be treated with high strength opioids. Other Some routes of administration such as nasal sprays and inhalers generally result in a faster onset of high blood levels, which can provide more immediate analgesia but also more severe side effects, especially in overdose. The much higher cost of some of these appliances may not be justified by marginal benefit compared with buccal or oral options. Intranasal<unk>  appears to be equally effective as IV morphine and superior to intramuscular morphine for the management of acute hospital pain. A<unk>  patient-controlled transdermal system (PCTS) is under development, which aims to allow patients to control administration of<unk>  through the skin to treat postoperative pain.
Fentanyl
Remifentanil
Ketamine
Alfentanil
Propofol
Etomidate
Sevoflurane
Methoxyflurane