Since 2019, xylazine, a powerful animal tranquilizer, started appearing in street fentanyl. It has since spread throughout the United States, including in 99% of the street fentanyl in Philadelphia, according to a study last year done with the city’s health department.
While there is much that scientists do not understand about the drug’s effects and how to treat it, local research on people who use the drug shows that the painful withdrawal effects keeps them using it, and also offers a new way to manage those symptoms for long enough to get them medical care.
Last year, public health researcher Megan Reed surveyed people who use drugs in Philadelphia to study the effects of xylazine. Of the 17 people she talked to, 16 told her they hated xylazine, but cannot get off it because of the “excruciating” pain of withdrawal. In the past, they might use heroin or fentanyl every five to eight hours, but need to use xylazine much more frequently, said Reed, an assistant professor at Thomas Jefferson University.