Metopon (5-methylhydromorphone) is an

opioid Opioids are substances that act on opioid receptors to produce morphine-like effects. Medically they are primarily used for pain relief, including anesthesia. Other medical uses include suppression of diarrhea, replacement therapy for opioid us ...

analogue that is a methylated derivative of

hydromorphone Hydromorphone, also known as dihydromorphinone, and sold under the brand name Dilaudid among others, is an 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 mou ...

which was invented in 1929 as an

analgesic An analgesic drug, also called simply an analgesic (American English), analgaesic (British English), pain reliever, or painkiller, is any member of the group of drugs used to achieve relief from pain (that is, analgesia or pain management). It ...

. 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, although it does have a slightly lower tendency to produce nausea and respiratory depression compared to morphine. 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. 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 and the bulk of the research on the drug at this time is taking place in Germany, Switzerland, and Austria.

CAS number A CAS Registry Number (also referred to as CAS RN or informally CAS Number) is a unique identification number assigned by the Chemical Abstracts Service (CAS), US to every chemical substance described in the open scientific literature. It inclu ...

124-92-5 (Metopon hydrochloride)

Synthesis

References

{{Opioidergics 4,5-Epoxymorphinans Ketones Mu-opioid receptor agonists Phenols Semisynthetic opioids

Synthesis

See also

References