Epidemiology of Xylazine-Positive Fatal Overdoses in Milwaukee County, Wisconsin, 2019-2023.

Introduction: Xylazine association with fentanyl poses an emerging threat to public health. We conducted a retrospective study to analyze xylazine-related fatal overdoses in Milwaukee County, Wisconsin from 2019 through 2023.

Methods: Using medical examiner data, we compared fatal xylazine overdoses (n = 243) with fentanyl overdoses without xylazine (n = 1946). Demographic, polysubstance, temporal, and geographic characteristics were analyzed.

Results: Xylazine fatalities have surged since 2019, exhibiting different polysubstance profiles than fentanyl overdoses without xylazine. We identified 8 geospatial clusters contributing to 64% of xylazine overdoses.

Discussion: We encourage localized interventions to address the xylazine-fentanyl syndemic. Policy measures such as Wisconsin Act 217, which legalized xylazine testing materials, promote evidence-based harm reduction tools to mitigate the risks associated with xylazine's increasing prevalence in the Midwest.