"The extremely potent and toxic nature of ISOs [Illicit/Synthetic Opioids] has rendered them the primary cause of overdose fatalities while consequently presenting major challenges for the menu of available interventions. Many existing interventions have mostly aimed at either manipulating the drug use environment to be safer (e.g., supervised consumption) or reactively treating underlying drug use disorders (OAT) or overdoses (naloxone). These approaches, however, have limited direct impact on the primary vector of highly potent and toxic ISO drugs causing overdose deaths (Fischer et al., 2019, 2020b). For illustration: More than half of recent overdose fatalities in British Columbia have occurred from inhalation rather than injection drug use—a mode of use traditionally viewed as substantially safer and protective against overdose-related death (BC Coroners, 2023; Fischer, 2023;Thiblin et al., 2004).

"The search for more effective interventions has thus increasingly focused on the need for safer drug supply provision as an emergency measure to address and reduce the risk of deaths caused by ISO exposure (Ivsins et al., 2020; Tyndall, 2020). Conceptually and practically, safer supply measures provide a form of vector intervention toward reducing the drug consumer's exposure to highly potent/toxic ISO drugs and therefore the consequential risk of overdose death (Fischer et al., 2020b). Based on this premise, the first Canadian small-scale safer supply programs began operating in Ontario from 2017 onward, initially providing prescribed pharmaceutical-grade hydromorphone to small numbers of at-risk drug consumers. Similar programs were subsequently implemented in other locations, with some offering alternative opioid formulations and/or dispensing modes. Safer supply programs became officially supported by the federal government of Canada as of 2020 (Government of Canada, 2023; Harris et al., 2021; Tyndall, 2020; Young et al., 2022). In 2021, the province of British Columbia phased in its formal prescribed safer supply policy for regulatory guidance (Ministry of Mental Health and Addictions, 2021)."