W-18 was invented at the University of Alberta by a lab working on analgesic drug discovery in the 1980s, and preliminary studies in animals showed it had pain-killing activity in mice.

[1][2] The chemical was detected in connection with recreational drug use as substitute for other controlled substances in Europe in 2013,[3] and in the United States.

[4] In Canada, Alberta Law Enforcement Response Teams (ALERT) seized four kilograms of W-18 in a drug bust in Edmonton in December 2015[5] and W-18 was also detected by Health Canada in at least three of 110 fentanyl tablets seized from a Calgary home in August 2015.

[6][4] W-18 was commonly reported to be an opioid in the popular press in the 2010s, which was later revealed not to be correct.

[9] It also inhibits the hERG potassium channel with micromolar affinity, which could potentially cause cardiac arrhythmia at high doses.