Xylazine Use Among Adults Seeking Substance Use Treatment, 2022–2023

Xylazine, a sedative that is not an opioid, has increasingly been found in illegally manufactured fentanyl (IMF) and in U.S. overdose deaths, most of which also involve IMF. In 21 jurisdictions, IMF-involved deaths with xylazine detected rose 276% from January 2019 to June 2022. Drugs sold as heroin increasingly contain IMF, so people seeking heroin may take IMF knowingly or not. Xylazine has also been linked to skin wounds that seem to occur however it is taken.

To guide prevention and response, CDC researchers studied adults who used IMF or heroin and answered questions about xylazine when they were assessed for substance use treatment.

The data

The information came from a convenience sample of adults assessed from July 2022 to September 2023 with the Addiction Severity Index–Multimedia Version (ASI-MV), a self-administered clinical tool used at treatment programs and other sites such as criminal justice programs, drug courts and homeless services. It asks about demographics, substance use, how drugs are taken and overdose history. The questionnaire described xylazine as sometimes combined with heroin, fentanyl or cocaine and known by names such as "sleep cut," "tranq dope" and "Anestesia de Caballo."

Of 45,015 adults assessed, 70.4% were in the South; 1,068 who did not answer the xylazine questions were excluded, leaving 43,947. Of those, 6,415 (14.6%) named IMF or heroin as their main lifetime substance use problem, 5,344 (12.2%) had used IMF or heroin in the past 30 days, and 1,924 (4.4%) had ever used xylazine.

Adults whose main problem was IMF or heroin

Of the 6,415, 817 (12.7%) had ever used xylazine. The group's median age was 34; most were men (60.7%), non-Hispanic white (78.0%), had a high school education or less (73.5%) and had started treatment before (77.6%). Those who had used xylazine did not differ significantly in these respects from those who had not, but they:

• more often used at least one other substance recently;
• more often reported polysubstance use, meaning two or more other substances besides IMF or heroin and xylazine in the past 30 days (57.2% versus 36.1%);
• reported more lifetime nonfatal overdoses from any drug (median two versus one);
• were nearly twice as likely to have recently misused prescription opioids (63.4% versus 35.8%).

Among those who had used xylazine, the most common recent drugs were misused prescription opioids (63.4%), IMF (60.6%) and heroin (45.4%). Most (58.5%) took xylazine by swallowing, snorting or smoking it without injecting; 31.7% injected it.

Adults who had recently used IMF or heroin

Of the 5,344, 443 (8.3%) had used xylazine in the past 30 days. Compared with those who had not, they were more often women (42.0% versus 34.7%), more often reported recent polysubstance use (84.9% versus 57.8%), reported more lifetime nonfatal overdoses (median two versus one), and more often used every other substance asked about, from prescription stimulant misuse (11.3% versus 2.8%) to IMF (94.6% versus 83.2%). Most (65.2%) did not inject xylazine; 30.7% did.

What it means

It is not clear whether xylazine itself raises the risk of an IMF overdose; an earlier analysis found the circumstances of IMF deaths were largely similar with and without xylazine. The link with more nonfatal overdoses may reflect polysubstance use, which is associated with both. Naloxone cannot reverse xylazine, but it should still be distributed more widely, because xylazine is usually combined with IMF, whose effects naloxone does reverse. More research is needed on whether xylazine use signals other drug use or brings distinct withdrawal and dependence problems, and what that means for treating opioid use disorder.

People with extensive xylazine-related wounds may struggle to get substance use treatment and wound care, which can worsen both their drug use and their wounds. Reducing stigma about drug use, and about wounds as a sign of it, helps link people to low-barrier treatment, harm reduction and wound care. People who use drugs have said they want xylazine test strips, and expanding clinical care and drug checking, such as fentanyl and xylazine test strips, could draw more people into harm reduction.

The authors call for linking people who use xylazine to effective treatment, including medications for opioid use disorder where appropriate, keeping them in care, expanding naloxone, and offering harm reduction services and wound care without judgment.

Limits

Xylazine use was self-reported and not confirmed by testing, and because it is often mixed into other drugs, people may not have known they took it. Answers may be affected by memory or the wish to give acceptable answers, and people who use many drugs may be more likely to have heard of xylazine. The questionnaire did not ask whether use was intentional; a survey in Philadelphia found most people who inject drugs prefer to avoid xylazine. It did not record when each drug was used, or capture xylazine used without IMF or heroin. The sample was not representative and came mostly from the South, where the drug supply may differ from elsewhere.

Sources

• Jiang X, Connolly S, Strahan AE, et al. Reported Xylazine Use Among Adults Aged ≥18 Years Evaluated for Substance Use Treatment — United States, July 2022–September 2023. MMWR Morb Mortal Wkly Rep 73(26). https://www.cdc.gov/mmwr/volumes/73/wr/mm7326a2.htm
• CDC, fentanyl overdose prevention: https://www.cdc.gov/overdose-prevention/about/fentanyl.html