oxymorphazone oxymorphazone oxymorphazone is an opioid analgesic drug related to oxymorphone. oxymorphazone is a potent and long acting μ-opioid agonist which binds irreversibly to the receptor, forming a covalent bond which prevents it from detaching once bound. this gives it an unusual pharmacological profile, and while oxymorphazone is only around half the potency of oxymorphone, with higher doses the analgesic effect becomes extremely long lasting, with a duration of up to 48 hours. however, tolerance to analgesia develops rapidly with repeated doses, as chronically activated opioid receptors are rapidly internalised by β-arrestins, similar to the results of non-covalent binding by repeated doses of agonists with extremely high binding affinity such as lofentanil. not to be confused with oxymorphone. oxymorphazoneclinical dataother namesoxymorphone hydrazoneatc codenoneidentifiers iupac name (5α,6e)-3,14-dihydroxy-17-methyl-4,5-epoxy-morphinan-6-one hydrazone cas number73697-35-5 ypubchem cid9577748chemspider23231158unii9j727k8r3uchemical and physical dataformulac17h21n3o3molar mass315.373 g·mol−13d model (jsmol)interactive image smiles cn1cc234/c(=n/n)/cc2(1cc5=c3c(=c(c=c5)o)o4)o inchi inchi=1s/c17h21n3o3/c1-20-7-6-16-13-9-2-3-11(21)14(13)23-15(16)10(19-18)4-5-17(16,22)12(20)8-9/h2-3,12,15,21-22h,4-8,18h2,1h3/b19-10-/t12-,15+,16+,17-/m1/s1key:voftyifrrwvmoo-ykkxutdfsa-n (verify)