The current overdose crisis is one of the most devastating public health challenges in the field of mental health and substance use disorder care in history. Globally, about 1 in 5 deaths is attributable to substance use, with more than 70% attributable to opioids. The dramatic increase in mortality in Canada and the USA since 2015 is primarily due to changing drug markets and related patterns of substance use, and an ill-prepared system of care. In the USA, the economic cost of drug abuse is estimated to be $193 billion dollars annually, which includes healthcare costs, loss of productivity and criminal justice costs.

Fentanyl now dominates the pattern of use in most regions of North America and has become the drug of choice among many people who use drug (PWUD). This shift towards high-potent synthetic opioids has not stopped at fentanyl, with ultra-potent synthetic fentanyl derivatives such as carfentanil as well as non-fentanyl-derived ultra-potent synthetic opioids such as Nitazene now becoming readily available.5,6 The latter, from a drug class known as benzimidazole-opioids, is several times more potent than fentanyl and is undetectable using currently available fentanyl test strips...