Background:
Xylazine is a veterinary sedative that first emerged in Puerto Rico’s unregulated drug market prior to its dominance in the mainland United States, where Philadelphia – the U.S.’s largest open air drug market – has since seen widespread xylazine proliferation. Xylazine use is associated with severe health issues, including soft-tissue and skin wounds. We examined xylazine-related characteristics in Puerto Rico and Philadelphia, the epicenters of xylazine adulteration.
Methods:
In 2024, we collected 277 street opioid samples (49 in eastern Puerto Rico, 228 in Philadelphia). Using mass spectrometry, we assessed xylazine prevalence and concentration. Brief surveys measured xylazine awareness, while extended surveys with 47 Philadelphia participants explored the perceived difficulty of obtaining xylazine-free opioids, changes in consumption volume, and attitudes toward xylazine, including intentional use, preferences, and concerns.
Results:
Xylazine was detected in 19/49 (39%) samples in Puerto Rico and 154/228 (68%) in Philadelphia. While participants in Puerto Rico believed xylazine was present in 0% of xylazine-positive samples, participants in Philadelphia believed xylazine was present in 99% of xylazine-positive samples. The average concentration was 4.6%-by-mass in Puerto Rico compared to 14%-by-mass in Philadelphia. The prevalence and average concentration of xylazine decreased in each site over time. While 96% of participants reported intentionally using xylazine, only 6% preferred it. Most (89%) felt worried about xylazine and 62% believed obtaining opioids without xylazine would be difficult. Average daily volume of street opioid consumption decreased from 6.6 to 5.7 bags after xylazine appeared.
Conclusions:
While xylazine remains a key adulterant of street opioid supplies in Puerto Rico and Philadelphia, there has been a recent decrease in its prevalence and concentration. People are typically unaware of whether and/or to what extent xylazine is present. Xylazine is not preferred and causes significant worry. Tracking epidemiological and behavioral shifts in xylazine use is crucial for addressing xylazine-related harms. |