metethoheptazine metethoheptazine metethoheptazine (wy-535) is an opioid analgesic from the phenazepine family. it was invented in the 1960s. metethoheptazineclinical dataother nameswy-535atc codenoneidentifiers iupac name ethyl 1,3-dimethyl-4-phenylazepane-4-carboxylate cas number509-84-2 npubchem cid176888chemspider154060 yuniis36j5zy2thchemical and physical dataformulac17h25no2molar mass275.392 g·mol−13d model (jsmol)interactive image smiles o=c(occ)c2(c1ccccc1)cccn(c)cc2c inchi inchi=1s/c17h25no2/c1-4-20-16(19)17(15-9-6-5-7-10-15)11-8-12-18(3)13-14(17)2/h5-7,9-10,14h,4,8,11-13h2,1-3h3 ykey:bosuldnqdjlkkl-uhfffaoysa-n y ny (what is this?) (verify) metethoheptazine produces similar effects to other opioids, including analgesia, sedation, dizziness and nausea. metethoheptazine is not listed as a controlled substance under the controlled substances act 1970 in the united states. the canadian controlled drugs and substances act specifically excludes the phenazepine opioids from control.