Title: Diprenorphine
CAS Registry Number: 14357-78-9
CAS Name: (5a,7a)-17-(Cyclopropylmethyl)-4,5-epoxy-18,19-dihydro-3-hydroxy-6-methoxy-a,a-dimethyl-6,14-ethenomorphinan-7-methanol
Additional Names: 21-cyclopropyl-6,7,8,14-tetrahydro-7a-(1-hydroxy-1-methylethyl)-6,14-endo-ethanooripavine; N-(cyclopropylmethyl)-19-methylnororvinol
Manufacturers' Codes: M-5050; RX-5050M
Molecular Formula: C26H35NO4
Molecular Weight: 425.56
Percent Composition: C 73.38%, H 8.29%, N 3.29%, O 15.04%
Literature References: Closely related to cyprenorphine, q.v. Prepn: K. W. Bentley, D. G. Hardy, J. Am. Chem. Soc. 89, 3281 (1967). Activity in rats: G. F. Blane, J. Pharm. Pharmacol. 19, 367 (1967); G. F. Blane, D. Dugdall, ibid. 20, 547 (1968). Use as etorphine antagonist in dogs: M. Grange et al., Rev. Med. Vet. 124, 899 (1973); in large animals: B. T. Alford et al., J. Am. Vet. Med. Assoc. 164, 702 (1974). Binding to opiate receptors: C. B. Pert et al., Life Sci. 16, 1849 (1975); J. Pearson et al., ibid. 26, 1047 (1980); to m opiate receptors: J. J. Frost et al., ibid. 38, 1597 (1986). Treatment of experimental stroke in cats: D. S. Baskin et al., Neuropeptides 5, 307 (1985); eidem, J. Neurosurg. 64, 99 (1986). Determn by HPLC: I. Jane, A. McKinnon, J. Chromatogr. 323, 191 (1985). Toxicity data: N. S. Duggett et al., Toxicol. Appl. Pharmacol. 31, 141 (1977).
Properties: Crystals from methanol, mp 185°.
Melting point: mp 185°
Derivative Type: Hydrochloride
Trademarks: Revivon (Reckitt & Colman)
Molecular Formula: C26H35NO4.HCl
Molecular Weight: 462.02
Percent Composition: C 67.59%, H 7.85%, N 3.03%, O 13.85%, Cl 7.67%
Properties: LD50 s.c. in mice: 316.0 ± 20 mg/kg (Duggett).
Toxicity data: LD50 s.c. in mice: 316.0 ± 20 mg/kg (Duggett)
Therap-Cat-Vet: Narcotic antagonist.
Dipropalin Dipropetryn Dipropyl Ketone Dipropylene Glycol Monomethyl Ether Dipyrocetyl

Systematic (IUPAC) name
(5α,7α)-17-(Cyclopropylmethyl)- 4,5-epoxy- 18,19-dihydro- 3-hydroxy- 6-methoxy- α,α-dimethyl- 6,14-ethenomorphinan- 7-methanol
Clinical data
AHFS/Drugs.com International Drug Names
Legal status  ?
CAS number 14357-78-9 N
ATCvet code QV03AB92
PubChem CID 443408
IUPHAR ligand 1617
DrugBank DB01548
ChemSpider 391634 YesY
KEGG D07863 YesY
Chemical data
Formula C26H35NO4 
Mol. mass 425.56 g/mol
 N (what is this?)  (verify)

Diprenorphine (diprenorfin, Revivon, M5050)[1] is an opioid antagonist[2] used to reverse the effects of the super-potent opioid analgesics such as etorphine and carfentanil that are used for tranquilizing large animals in veterinary medicine.

Diprenorphine is the strongest opiate antagonist that is commercially available (some 100 times more potent as an antagonist than nalorphine),[3] 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.[4] These super-potent opioids, with the single exception of buprenorphine, 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 leading to fatal respiratory depression. However conventional opioid derivatives are not strong enough to rapidly tranquilize large animals such as elephants and rhinos, so drugs such as etorphine or carfentanil are available for this purpose.

Diprenorphine is considered the specific antagonist for etorphine and carfentanil,[5] and is normally used to remobilise animals once veterinary procedures have been completed,.[6] Because diprenorphine also has some agonistic properties of its own, it should not be used on humans in the event that they are accidentally exposed to etorphine or carfentanil. Naloxone or naltrexone are the preferred human antagonists.[7]

In theory, diprenorphine could also be used as an antidote for treating overdose of certain opioid derivatives which are used in humans, such as 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 these drugs, so use of diprenorphine for treating e.g. a buprenorphine overdose is not carried out in practice, although it would work in theory.