Morphinans

Dextromethorphan is a cough suppressant used in many cough and cold medicines. In 2022, the US Food and Drug Administration (FDA) approved the combination dextromethorphan/bupropion to serve as a rapid-acting antidepressant in people with major depressive disorder.

Levorphanol (brand name Levo-Dromoran) is an opioid medication used to treat moderate to severe pain. It is the levorotatory enantiomer of the compound racemorphan. Its dextrorotatory counterpart is dextrorphan.

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.

Morphinan is the prototype chemical structure of a large chemical class of psychoactive drugs, consisting of opiate analgesics, cough suppressants, and dissociative hallucinogens, among others. Typical examples include compounds such as morphine, codeine, and dextromethorphan (DXM). Despite related molecular structures, the pharmacological profiles and mechanisms of action between the various types of morphinan substances can vary substantially. They tend to function either as μ-opioid receptor agonists (analgesics), or NMDA receptor antagonists (dissociatives).

Dextrorphan (DXO) is a psychoactive drug of the morphinan class which acts as an antitussive or cough suppressant and in high doses a dissociative hallucinogen. It is the dextrorotatory enantiomer of racemorphan; the levorotatory enantiomer is levorphanol. Dextrorphan is produced by O-demethylation of dextromethorphan by CYP2D6. Dextrorphan is an NMDA antagonist and contributes to the psychoactive effects of dextromethorphan.

Levomethorphan (LVM) (INN, BAN) is an opioid analgesic of the morphinan family that has never been marketed. It is the L-stereoisomer of racemethorphan (methorphan). The effects of the two isomers of racemethorphan are quite different, with dextromethorphan (DXM) being an antitussive at low doses and a hallucinogen at much higher doses. Levomethorphan is about five times stronger than morphine.

Phenomorphan is an opioid analgesic. It is not currently used in medicine, but has similar side-effects to other opiates, which include itching, nausea and respiratory depression.

Racemorphan, or morphanol, is the racemic mixture of the two stereoisomers of 17-methylmorphinan-3-ol, each with differing pharmacology and effects:

Levophenacylmorphan is a morphinan derivative that acts as an opioid agonist. It has potent analgesic effects and is around 10x more potent than morphine. Adverse effects associated with its use are those of the opioids as a whole, including pruritus, nausea, respiratory depression, euphoria and development of tolerance and dependence to its effects.

Levallorphan (INN, BAN; USAN levallorphan tartrate; brand names Lorfan, Naloxifan, and Naloxiphan) is an opioid modulator of the morphinan family used as an opioid analgesic and opioid antagonist/antidote. It acts as an antagonist of the μ-opioid receptor (MOR) and as an agonist of the κ-opioid receptor (KOR), and as a result, blocks the effects of stronger agents with greater intrinsic activity such as morphine whilst simultaneously producing analgesia.

Drotebanol (Oxymethebanol) is a morphinan derivative that acts as an opioid agonist. It was invented by Sankyo Company in Japan during the 1970s. It is synthesised from thebaine.

Samidorphan (, ) is an opioid antagonist that in the form of olanzapine/samidorphan (sold as Lybalvi) is used in the treatment of schizophrenia and bipolar disorder. Samidorphan reduces the weight gain associated with olanzapine. Samidorphan is taken by mouth.

Norlevorphanol is an opioid analgesic of the morphinan family that was never marketed. It is the levo-isomer of 3-hydroxymorphinan (morphinan-3-ol). Norlevorphanol is a Schedule I Narcotic controlled substance in the United States with an ACSCN of 9634 and in 2014 it had an annual aggregate manufacturing quota of 52 grams. It is used as the hydrobromide (free base conversion ratio 0.750) and hydrochloride (0.870). It has morphine-like pharmacological properties.

Salutaridine, also known as floripavine, is an alkaloid that is present in the morphinan alkaloid pathway of opium poppy, Papaver somniferum.

3-Methoxymorphinan is an inactive metabolite of both dextromethorphan and levomethorphan, and has been shown to produce local anesthetic effects. It is the CYP3A4 metabolite of the aforementioned drugs, and is itself metabolized by the liver enzyme CYP2D6.

Ro4-1539 (furethylnorlevorphanol) is an opioid analgesic drug from the morphinan series that was discovered by the pharmaceutical company Hoffmann–La Roche in the 1950s. It acts as a potent μ-opioid agonist, and was found to be around 30-60 times more potent than the related drug levorphanol in animal experiments. Although it has high potency, long duration, and good therapeutic index (1100 in animal studies), Ro4-1539 had no particular clinical advantages over other available opioid drugs, and was never commercially marketed.

Dimemorfan (INN; JAN dimemorfan phosphate; also known as dimemorphan and 3,17-dimethylmorphinan; brand names Astomin, Dastosirr, and Tusben) is an antitussive (cough suppressant) of the morphinan family that is widely used in Japan and is also marketed in Spain and Italy. It was developed by Yamanouchi Pharmaceutical (now Astellas Pharma) and introduced in Japan in 1975. It was later introduced in Spain in 1981 and Japan in 1985.

Methorphan is an opioid drug that occurs in two isomeric forms, each with differing pharmacology and effects:

Sinomenine or cocculine is an alkaloid found in the root of the climbing plant Sinomenium acutum which is native to Japan and China. The plant is traditionally used in herbal medicine in these countries for rheumatism and arthritis. However, analgesic action against other types of pain seems to be limited. Sinomenine is a morphinan derivative that is related to the common cough suppressant dextromethorphan. The drug's anti-rheumatic effects are thought to be primarily mediated via release of histamine, but other effects such as inhibition of prostaglandin, leukotriene and nitric oxide synthesi

Xorphanol (INN; also known as xorphanol mesylate (USAN); developmental codes TR-5379 or TR-5379M) is an opioid analgesic of the morphinan family that was never marketed.

Cyclorphan is an opioid analgesic of the morphinan family that was never marketed. It acts as a μ-opioid receptor (MOR) weak partial agonist or antagonist, κ-opioid receptor (KOR) full agonist, and, to a much lesser extent, δ-opioid receptor (DOR) agonist (75-fold lower affinity relative to the KOR). The drug was first synthesized in 1964 by scientists at Research Corporation. In clinical trials, it had relatively long duration, good absorption, and provided strong pain relief but produced psychotomimetic effects via KOR activation, so its development was not continued.