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Formula | C18H21NO3 |
Molar mass | 299.370 g·mol−1 |
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Metopon (5-methylhydromorphone, CAS number 124-92-5) [2] is an opioid analogue that is a methylated derivative of hydromorphone which was invented in 1929 as an analgesic. [3]
Metopon is sometimes used in medicine. Although longer acting than hydromorphone, metopon is less potent and its oral bioavailability is fairly low. Generally, metopon has few advantages to distinguish it from other, more commonly used opioid analgesics, [4] although it does have a slightly lower tendency to produce nausea and respiratory depression compared to morphine. [5]
In Canada, as of 1948, the hydrochloride of metopon (free base conversion ratio 0.891, molecular weight 335.8) was available only for oral administration for malignant pain and for maintenance of those habituated to morphine; the only dosage form available was singly scored 8 mg tablets. It was manufactured by Parke, Davis, & Co., and was only for sale to doctors and hospitals. Parke, Davis & Co. did not sell metopon to pharmacies. [6] It is unknown whether metopon tablets are still manufactured and sold in Canada.
Metopon tablets, ampoules, and suppositories are available in Switzerland, Austria, Germany, and other countries in Continental Europe and the drug is used in Patient Controlled Analgesia pumps for severe chronic pain in particular. Metopon is listed under Schedule II of the US Controlled Substances Act 1970, meaning it has an accepted medical use, but at this time it is not produced commercially and is seen only in laboratory research. It did see some use in medicine — oncology in particular — in the US in the 1950s. Currently metopon, which has a DEA ACSCN of 9260, does not have an annual manufacturing quota listed in the Federal Register [7] and the bulk of the research on the drug at this time is taking place in Germany, Switzerland, and Austria.
Hydromorphone, also known as dihydromorphinone, and sold under the brand name Dilaudid among others, is a morphinan opioid used to treat moderate to severe pain. Typically, long-term use is only recommended for pain due to cancer. It may be used by mouth or by injection into a vein, muscle, or under the skin. Effects generally begin within half an hour and last for up to five hours. A 2016 Cochrane review found little difference in benefit between hydromorphone and other opioids for cancer pain.
Oxymorphone is a highly potent opioid analgesic indicated for treatment of severe pain. Pain relief after injection begins after about 5–10 minutes, after oral administration it begins after about 30 minutes, and lasts about 3–4 hours for immediate-release tablets and 12 hours for extended-release tablets. The elimination half-life of oxymorphone is much faster intravenously, and as such, the drug is most commonly used orally. Like oxycodone, which metabolizes to oxymorphone, oxymorphone has a high potential to be abused.
Dihydrocodeine is a semi-synthetic opioid analgesic prescribed for pain or severe dyspnea, or as an antitussive, either alone or compounded with paracetamol (acetaminophen) or aspirin. It was developed in Germany in 1908 and first marketed in 1911.
Dipipanone, sold under the brand names of Pipadone and Diconal is a strong opioid analgesic drug, used for acute pain by mouth (PO) for adults. It is often used in instances where morphine is indicated but cannot be used due to the patient being allergic to morphine. In analgesic potency 25 mg dipipanone is approximately equivalent to 10 mg morphine.
Butorphanol is a morphinan-type synthetic agonist–antagonist opioid analgesic developed by Bristol-Myers. Butorphanol is most closely structurally related to levorphanol. Butorphanol is available as the tartrate salt in injectable, tablet, and intranasal spray formulations. The tablet form is only used in dogs, cats and horses due to low bioavailability in humans.
Thebacon, or dihydrocodeinone enol acetate, is a semisynthetic opioid that is similar to hydrocodone and is most commonly synthesised from thebaine. Thebacon was invented in Germany in 1924, four years after the first synthesis of hydrocodone. Thebacon is a derivative of acetyldihydrocodeine, where only the 6–7 double bond is saturated. Thebacon is marketed as its hydrochloride salt under the trade name Acedicon, and as its bitartrate under Diacodin and other trade names. The hydrochloride salt has a free base conversion ratio of 0.846. Other salts used in research and other settings include thebacon's phosphate, hydrobromide, citrate, hydroiodide, and sulfate.
Nicomorphine is the 3,6-dinicotinate ester of morphine. It is a strong opioid agonist analgesic two to three times as potent as morphine with a side effect profile similar to that of dihydromorphine, morphine, and diamorphine.
Nicocodeine is an opioid analgesic and cough suppressant, an ester of codeine closely related to dihydrocodeine and the codeine analogue of nicomorphine. It is not commonly used in most countries, but has activity similar to other opiates. Nicocodeine and nicomorphine were synthesized in 1904, and introduced in 1957 by Lannacher Heilmittel of Austria. Nicocodeine is metabolised in the liver by demethylation to produce nicomorphine, also known as 6-nicotinoylmorphine, and subsequently further metabolised to morphine. Side effects are similar to those of other opiates and include itching, nausea and respiratory depression. Related opioid analogues such as nicomorphine and nicodicodeine were first synthesized. The definitive synthesis, which involves treating anhydrous codeine base with nicotinic anhydride at 130 °C, was published by Pongratz and Zirm in Monatshefte für Chemie in 1957, simultaneously with the two analogues in an article about amides and esters of various organic acids.
Phenadoxone is an opioid analgesic of the open chain class invented in Germany by Hoechst in 1947. It is one of a handful of useful synthetic analgesics which were used in the United States for various lengths of time in the 20 or so years after the end of the Second World War but which were withdrawn from the market for various or no known reason and which now are mostly in Schedule I of the United States' Controlled Substances Act of 1970, or in Schedule II but not produced or marketed in the US. Others on this list are ketobemidone (Ketogin), dextromoramide, phenazocine, dipipanone, piminodine (Alvodine), propiram (Algeril), anileridine (Leritine) and alphaprodine (Nisentil).
Tilidine, sold under the brand name Valoron among others, is a synthetic opioid analgesic, used mainly in Belgium, Bulgaria, Germany, Albania, Luxembourg, South Africa, and Switzerland for the treatment of moderate to severe pain, both acute and chronic. Its onset of pain relief after oral administration is about 10–15 minutes and peak relief from pain occurs about 25–50 minutes after administration.
Tapentadol, sold under the brand names Nucynta and Palexia among others, is a synthetic opioid analgesic of the benzenoid class with a dual mode of action as a highly selective full agonist of the μ-opioid receptor and as a norepinephrine reuptake inhibitor (NRI). Tapentadol is used medically for the treatment of moderate to severe pain. It is addictive, a commonly abused drug, and poses a high risk of physical and/or mental dependence.
Metazocine is an opioid analgesic related to pentazocine. While metazocine has significant analgesic effects, mediated through a mixed agonist–antagonist action at the mu opioid receptor, its clinical use is limited by dysphoric and hallucinogenic effects which are most likely caused by activity at kappa opioid receptors and/or sigma receptors.
Trimeperidine is an opioid analgesic that is an analogue of prodine. It was developed in the early 1950s in the USSR during research into the related drug pethidine.
Phenazocine is an opioid analgesic drug, which is related to pentazocine and has a similar profile of effects.
Propiram is a partial μ-opioid receptor agonist and weak μ antagonist analgesic from the ampromide family of drugs related to other drugs such as phenampromide and diampromide. It was invented in 1963 in the United Kingdom by Bayer but was not widely marketed, although it saw some limited clinical use, especially in dentistry. Propiram reached Phase III clinical trials in the United States and Canada.
Myrophine (Myristylbenzylmorphine) is an opiate analogue that was developed in 1952. It is a derivative of morphine.
Desomorphine is a semi-synthetic opioid commercialized by Roche, with powerful, fast-acting effects, such as sedation and analgesia. It was first discovered and patented in Germany by a German team working for Knoll in 1920 but was not generally recognized. It was later synthesized in 1932 by American chemist Lyndon Frederick Small. Small also successfully patented it in 1934 in the United States. Desomorphine was used in Germany, Austria, and Switzerland under the brand name Permonid and was described as having a fast onset and a short duration of action, with relatively little nausea compared to equivalent doses of morphine. Dose for dose it is roughly ten times more potent than morphine, with 1 mg desomorphine being equivalent 10 mg morphine, via the intravenous (IV) or intramuscular (IM) routes.
Normorphine is an opiate analogue, the N-demethylated derivative of morphine, that was first described in the 1950s when a large group of N-substituted morphine analogues were characterized for activity. The compound has relatively little opioid activity in its own right, but is a useful intermediate which can be used to produce both opioid antagonists such as nalorphine, and also potent opioid agonists such as N-phenethylnormorphine. with its formation from morphine catalyzed by the liver enzymes CYP3A4 and CYP2C8.
Isomethadone (INN, BAN; trade name Liden; also known as isoamidone) is a synthetic opioid analgesic and antitussive related to methadone that was used formerly as a pharmaceutical drug but is now no longer marketed. Isomethadone was used as both an analgesic and antitussive. It binds to and activates both the μ- and δ-opioid receptors, with the (S)-isomer being the more potent of the two enantiomers. Isomethadone is a Schedule II controlled substance in the United States, with an ACSCN of 9226 and a 2014 aggregate manufacturing quota of 5 g. The salts in use are the hydrobromide (HBr, free base conversion ratio 0.793), hydrochloride (HCl, 0.894), and HCl monohydrate (0.850). Isomethadone is also regulated internationally as a Schedule I controlled substance under the United Nations Single Convention on Narcotic Drugs of 1961.
Desocodeine is a potent semi-synthetic opioid which is the penultimate intermediate in the manufacture of desomorphine from codeine. Desocodeine is a potent analgesic, being as potent as morphine. It is partially metabolized into desomorphine, among others, after parenteral and oral administration.