W-18 is a compound in a series of 32 substances (named W-1 to W-32) that were first synthesized in academic research on analgesic drug discovery in the 1980s and appeared as a designer drug in the 2010s.

Legal status
Legal status
  • Illegal in Sweden and Canada
CAS Number
PubChem CID
CompTox Dashboard (EPA)
Chemical and physical data
Molar mass421.8978 g/mol g·mol−1
3D model (JSmol)
Melting point157 to 158 °C (315 to 316 °F)
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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.[7][8][9]W-18 was found to obtain weak activity at both sigma receptors and the translocator protein (peripheral benzodiazepine receptor).[9] It also inhibits hERG binding, an important antitarget in drug discovery, which possibly causes cardiovascular side-effects.[9]

  • In Sweden, W-18 was made illegal in January 2016.[10]
  • In Canada, W-18 and its analogues were made Schedule I controlled substances.[11] 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 W-18 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.

See alsoEdit


  1. ^ Kroll, David (30 April 2016). "W-18, The High-Potency Research Chemical Making News: What It Is And What It Isn't". Forbes.
  2. ^ Warnica, Marion (21 April 2016). "Street drug W-18 is highly lethal, and still legal". CBC News. Retrieved 20 April 2016.
  3. ^ Gonçalves, Jacqueline (13 February 2016). "Notice to interested parties — Proposal regarding the scheduling of W-18 under the Controlled Drugs and Substances Act and its regulations". Canada Gazette. Government of Canada. 150 (7). Retrieved 19 February 2016.
  4. ^ a b Markusoff, Jason. "A toxic drug, more powerful than fentanyl, hits the streets in Alberta". macleans.ca. Maclean's. Retrieved 19 February 2016.
  5. ^ "Illicit drug W-18 is 100 times stronger than fentanyl, police warn". CBC News. 20 April 2016. Retrieved 20 April 2016.
  6. ^ Elkin, Allison (1 February 2016). "Everything We Know So Far About W-18, the Drug That's 100 Times More Powerful Than Fentanyl". Vice.com. Vice Media. Retrieved 20 April 2016.
  7. ^ Southwick, Reid (1 June 2016). "Health Canada statements on W-18 misleading, potentially wrong, experts warn". Calgary Herald. Postmedia Network Inc. Retrieved 22 June 2016.
  8. ^ Rachel Browne (2 June 2016). "Canada's Ban on Ultra-Potent Drug W-18 Could Make Things Worse". Vice.
  9. ^ a b c Huang, Xi-Ping; Che, Tao; Mangano, Thomas J.; Rouzic, Valerie Le; Pan, Ying-Xian; Cameron, Michael D.; Baumann, Michael H.; Pasternak, Gavril W.; Roth, Bryan L. (16 November 2017). "Fentanyl-related designer drugs W-18 and W-15 lack appreciable opioid activity in vitro and in vivo". JCI Insight. 2 (22). doi:10.1172/jci.insight.97222. ISSN 0021-9738. PMC 5752382. PMID 29202454.
  10. ^ "31 nya ämnen kan klassas som narkotika eller hälsofarlig vara" (in Swedish). Folkhälsomyndigheten. November 2015.
  11. ^ Denis Arsenault (1 June 2016). "Regulations Amending the Food and Drug Regulations (Parts G and J — Lefetamine, AH-7921, MT-45 and W-18)". Canada Gazette. Government of Canada. 150 (11).