Implementation of pharmaceutical alternatives to a toxic drug supply in British Columbia: A mixed methods study.

Background: North America has been in an unrelenting overdose crisis for almost a decade. British Columbia (BC), Canada declared a public health emergency due to overdoses in 2016. Risk Mitigation Guidance (RMG) for prescribing pharmaceutical opioids, stimulants and benzodiazepine alternatives to the toxic drug supply ("safer supply") was implemented in March 2020 in an attempt to reduce harms of COVID-19 and overdose deaths in BC during dual declared public health emergencies. Our objective was to describe early implementation of RMG among prescribers in BC.

Methods: We conducted a convergent mixed methods study drawing population-level linked administrative health data and qualitative interviews with 17 prescribers. The Consolidated Framework for Implementation Research (CFIR) informs our work. The study utilized seven linked databases, capturing the characteristics of prescribers for people with substance use disorder to describe the characteristics of those prescribing under the RMG using univariate summary statistics and logistic regression analysis. For the qualitative analysis, we drew on interpretative descriptive methodology to identify barriers and facilitators to implementation.

Results: Analysis of administrative databases demonstrated limited uptake of the intervention outside large urban centres and a highly specific profile of urban prescribers, with larger and more complex caseloads associated with RMG prescribing. Nurse practitioners were three times more likely to prescribe than general practitioners. Qualitatively, the study identified five themes related to the five CFIR domains: 1) RMG is helpful but controversial; 2) Motivations and challenges to prescribing; 3) New options and opportunities for care but not enough to 'win the arms race'; 4) Lack of implementation support and resources; 5) Limited infrastructure.

Conclusions: BC's implementation of RMG was limited in scope, prescriber uptake and geographic scale up. Systemic, organizational and individual barriers and facilitators point to the importance of engaging professional regulatory colleges, implementation planning and organizational infrastructure to ensure effective implementation and adaptation to context.