Xylazine in the drug supply: Emerging threats and lessons learned in areas with high levels of adulteration.

Background: Xylazine, a sedative analgesic drug approved as an animal tranquilizer but not for human use, has become an adulterant in the illicit opioid marketplace in North America. Recently declared an emerging health threat in the U.S., the prevalence of xylazine in overdose deaths increased 5.5-fold between 2019 and 2021. More information is needed about the impact of xylazine on opioid users and harm reduction service providers.

Methods: The impact of xylazine adulteration was triangulated through examination of (1) opioid overdose fatalities in Connecticut between 2017 and 2021 reported by the Office of the Chief Medical Examiner data, (2) a convenience survey of people in Connecticut who use drugs (PWUD) regarding their knowledge of and attitude about the local illicit drug supply, and (3) semi-structured interviews of harm reduction service providers in Connecticut and Philadelphia in response to prompts on the impacts of and responses to xylazine adulteration.

Results: The presence of fentanyl or its analogues in fatal opioid overdoses was a statistically significant predictor of xylazine presence [OR = 25.0, 95%CI (10.7,81.1)] as was being Hispanic [OR = 1.36, 95%CI (1.03,1.77)]. A survey of people who used drugs revealed that 43% (n = 286) were concerned that the drug supply was always unpredictable. Three-quarters of respondents were aware of xylazine and two-thirds would use a xylazine test strip if one was available. Respondents who identified as White, Hispanic were most likely to be aware of xylazine, to have used a fentanyl test strip, and to be interested in a xylazine test strip. Respondents who injected drugs were 3.6-fold more likely than those who did not inject to endorse an interest in a xylazine test strip. Harm reduction service providers were cognizant of a range of problems surrounding the use and injection of xylazine. Although they reported implementing practices to better respond to xylazine harms, they recognized the absence of solutions to many of the problems encountered.

Conclusion: The prevalence of xylazine has expanded, especially in combination with fentanyl. Harm reduction education efforts with fidelity to best practices have emerged, but the harms persist and community prevention needs are largely unmet.