|Chemical and physical data|
|Molar mass||423.545 g/mol g·mol−1|
|3D model (JSmol)|
Cyprenorphine (M-285) is an opioid drug. It is related to more well-known opioids such as buprenorphine, which is used as an analgesic and for the treatment of opioid addiction, and diprenorphine, which is used as an antidote to reverse the effects of other opioids.
Cyprenorphine has mixed agonist–antagonist effects at opioid receptors, like those of buprenorphine. However the effects of cyprenorphine are somewhat different, as it produces pronounced dysphoric and hallucinogenic effects which limit its potential use as an analgesic.
Cyprenorphine also has been shown to suppress the intake of sweet solution  but doesn’t suppress the increase in food consumption that’s produced by the alpha-2-adrenoceptor antagonist idazoxan. Idazoxan may lead to the release of endogenous opioid peptides and increase food intake, this effect is attenuated by (-)-naloxone but not by the mu/delta-antagonist cyprenorphine. 
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- Calcagnetti, Daniel J.; Calcagnetti, Robin Lynn; Fanselow, Michael S. (January 1990). “Centrally administered opioid antagonists, nor-binaltorphimine, 16-methyl cyprenorphine and MR2266, suppress intake of a sweet solution”. Pharmacology Biochemistry and Behavior. 35 (1): 69–73. doi:10.1016/0091-3057(90)90206-W.
- Jackson, Helen C.; Griffin, I.J.; Nutt, D.J. (August 1992). “Endogenous opioids may be involved in idazoxan-induced food intake”. Neuropharmacology. 31 (8): 771–776. doi:10.1016/0028-3908(92)90040-V.