Substance Use
Adulterants in Unregulated Opioids and Associations with Specific Adverse Events Samuel Tobias* Samuel Tobias Jennifer Angelucci Evan Wood Jane A. Buxton Lianping Ti
In recent years, the unregulated drug supply in North America has become permeated by novel adulterants (e.g., fentanyl analogues, benzodiazepines, xylazine) with limited information about their specific health effects. While fentanyl has been shown to be associated with overdose mortality and other non-fatal health outcomes, adverse events (AE) associated with novel adulterants remain largely unknown.
Drug checking samples were anonymously analyzed using combination Fourier-transform infrared spectroscopy and immunoassay strips at community harm reduction sites in British Columbia (BC) by trained technicians. Self-reported AE (e.g., non-fatal overdose, blackouts, prolonged sedation) were recorded from individuals who checked samples post-consumption. We restricted to samples reported by service users to be opioids. aPR and 95% CI of AE among common adulterants were calculated using generalized linear models with a Poisson and log link, adjusted for the presence of common adulterants and city.
Between Feb 2022 and Sep 2023, 9,999 eligible opioid samples were analyzed at community drug checking sites in BC. Of these, 42.4% were checked post-consumption by the participant. AE were noted by individuals in 17.1% of post-consumption checks. After adjustment, the presence of benzodiazepines in post-consumption opioid samples was positively associated with an increased likelihood of an AE (aPR = 1.86, 95%CI: 1.54–2.23). When restricted to specific events, benzodiazepines were associated with increased likelihood of overdose (aPR = 2.19, 95%CI: 1.67–2.88) and blackouts or prolonged sedation (aPR = 3.03, 95%CI: 2.04–4.49).
Prevalence of non-fatal AE associated with unregulated opioid use has been largely undescribed. This research reports specific AE associated with different adulterants in the unregulated opioid supply and the likely impact of benzodiazepines. With this information, precise public health interventions and services can target specific drug using populations.