Canada has been experiencing a public health crisis of high levels of overdose deaths mainly from toxic, synthetic opioids (e.g., fentanyl) drugs for more than a decade. While a wide range of prevention and treatment interventions to reduce overdose risk have been scaled up, drug overdose death levels have overall increased - reflecting similar US-based trends - before abruptly decreasing since 2023. These developments raise the crucial question: What factors have been driving the recent decreases in drug overdose deaths? We considered North America-based studies/data that examined potential supply-related factors. Emerging data suggest that while drug user-oriented prevention and treatment interventions have averted substantial numbers of overdose deaths, recent decreases in deaths appear to be associated mainly with changes in the global supply dynamics of toxic drugs, possibly related to intensified source control efforts (e.g., on fentanyl precursors) in China. Available data plausibly suggest that these changes may have affected both the composition and/or potency of illicit synthetic opioids available for consumption, and thereby reduced the population-based risks for and burden of overdose fatalities from exposure. While requiring further examination, these developments raise important questions about effective health-oriented overdose prevention measures and policy that are independent of unpredictable global drug supply dynamics.
Keywords: Canada; Health; Interventions; Mortality; Opioids; Overdose; Policy; Prevention; Supply; Synthetic drugs.
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