Injection of Xylazine: A contributing factor to HIV risk behaviors among Puerto Rican IV drug users

Background: Recent studies of injection drug users (IDUs) in Puerto Rico indicate widespread use of xylazine (horse anesthesia) mixed with heroin and cocaine. This study describes use of xylazine/mix and HIV risk behaviors. Methods: Data from 374 Puerto Rican IDUs was gathered through Spanish in-person interviews. Bi-variate and multivariable analyses were conducted to explore the association between xylazine use and HIV risk behaviors (sharing drug-paraphernalia, unprotected sex, sex work, injecting others) controlling for demographic characteristics, health care utilization; housing status, substance use history; and mental health symptoms. Results: On average, participants began using heroin and cocaine mixed with xylazine at age 31, whereas use of the same drugs without xylazine began between ages 18-21. Incidence of xylazine/mix injection in the sample was high (69.3%). At first use, participants who injected xylazine/mix knew it was not pure heroin because they felt a different high (76%) or had developed severe abscesses (28%). Bivariate analysis identified that xylazine/mix use was significantly associated with sharing drug-paraphernalia, unprotected sex, and injecting others. Logistic regression analysis, with all variables significant at the bivariate level, indicate that xylazine/mix use was significantly associated with higher numbers of unprotected sexual contacts in the last 30 days, controlling for age, gender, number of sexual contacts and homelessness (p≤.05). Conclusions: Future HIV prevention efforts in Puerto Rico must address xylazine/mix use and its association with HIV risk behaviors. The migratory pattern of Puerto Ricans IDUs traveling to and from the USA mainland, possibly carrying xylazine, raises additional public health concerns.