There’s evidence the much-talked-about street drug xylazine, which is typically used by veterinarians to sedate large animals, is infiltrating San Francisco’s drug supply. While concerning, public health officials don’t think xylazine, or “tranq,” as it’s often called, will cause the same sudden uptick in overdose deaths that fentanyl triggered five years ago.
“This is based on the overdose trends in cities in the East Coast, which have fluctuated over the past years despite the rising prevalence of xylazine,” Dr. Jeffrey Hom, director of population behavioral health for the San Francisco Department of Public Health, wrote in an email.
In routine toxicology testing on 145 people who died from drug overdoses in SF between mid-December 2022 and mid-January, xylazine was identified in the systems of four individuals, the city’s Department of Public Health said. The synthetic opioid fentanyl was also identified in all four people, according to the department.
Another point of reference: The department said it has not received any reports of xylazine-related wounds in city patients. The drug is known for causing skin lesions that can become so severe the amputation of limbs is required.
“While we do anticipate more cases involving xylazine will be identified, this low number of individuals initially testing positive, as well as the fact that we have not heard reports of wounds or intoxication suggestive of xylazine, supports our belief that it is not yet widespread in the local drug supply,” Hom said.
Fentanyl remains the main cause of overdoses in the city, but xylazine is concerning because its effects can’t be reversed by naloxone, which saves many people in the throes of fentanyl or other opioid overdoses. After drug overdose deaths began to rise sharply five years ago with fentanyl flooding streets, the city saw a slight decline in the last two years amid expanded programs such as Narcan distribution. San Francisco recorded 725 accidental drug overdoses in 2020; the city saw the number dip to 640 in 2021 and 620 in 2022. The hope is this downward trend will continue.
Xylazine was originally developed for veterinarians who need to sedate large animals, mainly horses, and is only authorized for veterinary use. It reportedly began to be used recreationally in the early 2000s in rural communities of Puerto Rico where drug users injected “anestesia de caballo.” The drug later flooded the Northeast’s white-powder heroin and fentanyl market in the late 2010s. The Drug Enforcement Administration said in an October 2022 report that while the Northeast remains the center of the xylazine market, the West Coast saw a 112% increase in forensic laboratory identifications of xylazine in confiscated drugs from 2020 to 2021.
Xylazine is cheap and often used to bulk up other drugs, such as fentanyl, cocaine and heroin, to increase drug sellers’ profit. Users can smoke, snort or inject it. They may unknowingly take it when it’s mixed in with other drugs. The DEA said more research is needed to determine the drug’s impacts on the human body, but drug users’ accounts indicate its effects are similar to opioids.
While the substance is being linked to an increasing number of drug overdoses across the country, its prevalence may be underestimated, as many counties across the U.S. don’t include it in forensic laboratory or toxicology testing, the DEA said.
San Francisco’s health department said it has received state funding to increase its testing for xylazine.
“We’re concerned about xylazine because of the suffering it has caused and the very harmful impacts it has had and continues to have in cities where the drug is prevalent,” Hom wrote. “This early identification is important to inform our response and it points to the need for expanded surveillance of a highly toxic and unregulated drug supply.”