In a June 1 news release, Health Canada said W-18 "can be 100 times stronger than fentanyl." Health Canada emphasized that it is not currently known whether overdose-reversing agent naloxone would be effective for someone who had taken W-18. On Tuesday, Health Canada noted the limitations of the research but said the available data suggests a "potentially severe risk for harm to individuals." Health Canada has taken a step back from claims that W-18 is a synthetic opioid that is 100 times more powerful than fentanyl, now acknowledging more research is needed. Therefore, if the research results are interpreted to mean W-18 is 10,000 times stronger than morphine, that would make the drug 100 times stronger than fentanyl.

Source: CBC News June 14, 2016 21:22 UTC