Diprenorphine (brand name Revivon; former developmental code name M5050), also known as diprenorfin, is a non-selective, high-

affinity Affinity may refer to: Commerce, finance and law * Affinity (law), kinship by marriage * Affinity analysis, a market research and business management technique * Affinity Credit Union, a Saskatchewan-based credit union * Affinity Equity Pa ...

, weak

partial agonist In pharmacology, partial agonists are drugs that bind to and activate a given Receptor (biochemistry), receptor, but have only partial Intrinsic activity, efficacy at the receptor relative to a full agonist. They may also be considered Ligand (bio ...

of the μ- (MOR), κ- (KOR), and

δ-opioid receptor The δ-opioid receptor, also known as delta opioid receptor or simply delta receptor, abbreviated DOR or DOP, is an inhibitory 7-transmembrane G-protein coupled receptor coupled to the G protein Gi alpha subunit, Gi/G0 and has enkephalins as it ...

(DOR) (with equal affinity) which is used in

veterinary medicine Veterinary medicine is the branch of medicine that deals with the prevention, management, medical diagnosis, diagnosis, and treatment of disease, disorder, and injury in non-human animals. The scope of veterinary medicine is wide, covering all a ...

as an

opioid antagonist An opioid antagonist, or opioid receptor antagonist, is a receptor antagonist that acts on one or more of the opioid receptors. Naloxone and naltrexone are commonly used opioid antagonist drugs which are competitive antagonists that bind to ...

. It is used to reverse the effects of super-potent

opioid Opioids are a class of Drug, drugs that derive from, or mimic, natural substances found in the Papaver somniferum, opium poppy plant. Opioids work on opioid receptors in the brain and other organs to produce a variety of morphine-like effects, ...

analgesic An analgesic drug, also called simply an analgesic, antalgic, pain reliever, or painkiller, is any member of the group of drugs used for pain management. Analgesics are conceptually distinct from anesthetics, which temporarily reduce, and in s ...

s such as etorphine and carfentanil that are used for tranquilizing large animals. The drug is not approved for use in humans. Diprenorphine is the strongest opioid antagonist that is commercially available (some 100 times more potent than nalorphine), and is used for reversing the effects of very strong opioids for which the binding affinity is so high that naloxone does not effectively or reliably reverse the narcotic effects. These super-potent opioids, with the single exception of buprenorphine (which has an improved safety-profile due to its partial agonism character), are not used in humans because the dose for a human is so small that it would be difficult to measure properly , so there is an excessive risk of

overdose A drug overdose (overdose or OD) is the ingestion or application of a drug or other substance in quantities much greater than are recommended. Retrieved on September 20, 2014.

leading to fatal respiratory depression. However conventional opioid derivatives are not strong enough to rapidly tranquilize large animals, like elephants and rhinos, so drugs such as etorphine and carfentanil are available for this purpose. Diprenorphine is considered to be the specific reversing agent/antagonist for etorphine and carfentanil, and is normally used to remobilise animals once veterinary procedures have been completed. Since diprenorphine also has partial agonistic properties of its own, it should not be used on humans if they are accidentally exposed to etorphine or carfentanil. Naloxone or naltrexone is the preferred human opioid receptor antagonist. In theory, diprenorphine could also be used as an antidote for treating overdose of certain opioid derivatives which are used in humans, particularly buprenorphine for which the binding affinity is so high that naloxone does not reliably reverse the narcotic effects. However, diprenorphine is not generally available in hospitals; instead a vial of diprenorphine is supplied with etorphine or carfentanil specifically for reversing the effects of the drug, so the use of diprenorphine for treating a buprenorphine overdose is not usually carried out in practice. Because diprenorphine is a weak partial agonist of the opioid receptors rather than a silent antagonist, it can produce some opioid effects in the absence of other opioids at sufficient doses. Moreover, due to partial agonism of the KOR, where it appears to possess significantly greater intrinsic activity relative to the MOR, diprenorphine can produce

sedation Sedation is the reduction of irritability or agitation by administration of sedative drugs, generally to facilitate a medical procedure or diagnostic procedure. Examples of drugs which can be used for sedation include isoflurane, diethyl ether, ...

as well as, in humans,

hallucination A hallucination is a perception in the absence of an external stimulus that has the compelling sense of reality. They are distinguishable from several related phenomena, such as dreaming ( REM sleep), which does not involve wakefulness; pse ...

References

{{Opioid receptor modulators Delta-opioid receptor antagonists Ethers Kappa-opioid receptor agonists Kappa-opioid receptor antagonists 4,5-Epoxymorphinans Mu-opioid receptor antagonists Hydroxyarenes Semisynthetic opioids Tertiary alcohols