Introduction: Substance-related acute toxicity deaths continue to be a serious public health concern in Canada. This study explored coroner and medical examiner (C/ME) perspectives of contextual risk factors and characteristics associated with deaths from acute toxic effects of opioids and other illegal substances in Canada.

Methods: In-depth interviews were conducted with 36 C/MEs in eight provinces and territories between December 2017 and February 2018. Interview audio recordings were transcribed and coded for key themes using thematic analysis.

Results: Four themes described the perspectives of C/MEs: (1) Who is experiencing a substance-related acute toxicity death?; (2) Who is present at the time of death?; (3) Why are people experiencing an acute toxicity death?; (4) What are the social contextual factors contributing to deaths? Deaths crossed demographic and socioeconomic groups and included people who used substances on occasion, chronically, or for the first time. Using alone presents risk, while using in the presence of others can also contribute to risk if others are unable or unprepared to respond. People who died from a substance-related acute toxicity often had one or more contextual risk factors: contaminated substances, history of substance use, history of chronic pain and decreased tolerance. Social contextual factors contributing to deaths included diagnosed or undiagnosed mental illness, stigma, lack of support and lack of follow-up from health care.

Conclusion: Findings revealed contextual factors and characteristics associated with substance-related acute toxicity deaths that contribute to a better understanding of the circumstances surrounding these deaths across Canada and that can inform targeted prevention and intervention efforts.