MT-45 (IC-6) is an opioidanalgesic drug invented in the 1970s by Dainippon Pharmaceutical Co. It is chemically a 1-substituted-4-(1,2-diphenylethyl)piperazine derivative, which is structurally unrelated to most other opioid drugs. Racemic MT-45 has around 80% the potency of morphine, with almost all opioid activity residing in the (S) enantiomer (the opposite stereochemistry from the related drug lefetamine). It has been used as a lead compound from which a large family of potent opioid drugs have been developed, including full agonists, partial agonists, and antagonists at the three main opioid receptor subtypes.
Recreational use of MT-45 has been associated with hearing loss and unconsciousness.
MT-45 became a class A drug in the UK on 11 March 2015
The Canadian Controlled Drugs and Substances Act was amended in 2016 to include the substance as a Schedule I substance. Possession without legal authority can result in maximum 7 years imprisonment. Further, Health Canada amended the Food and Drug Regulations in May, 2016 to classify MT-45 as a restricted drug. Only those with a law enforcement agency, person with an exemption permit or institutions with Minister's authorization may possess the drug in Canada.
In the United States the DEA placed MT-45 in Schedule 1 of the Controlled Substance Act. This took effect January 12, 2018. 
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