FDA warns xylazine-adulterated opioid overdoses on the rise


Veterinary tranquilizer does not respond to opioid-reversing drugs like naloxone, contributing to an increase in overdose deaths

opioids / Antonio Rodriguez / stock.adobe.com

Antonio Rodriguez / stock.adobe.com

Illicit drugs contaminated with Xylazine have exploded in popularity, leading to a nationwide increase in overdose deaths. The drug is increasingly being cut with opioids like fentanyl to lengthen the duration of the high. The danger to human patients, the FDA warned in a statement, is that nonopioid xylazine does not respond to overdose-reversal drugs like naloxone that are designed to counter the effects of opioid overdose.1

Xylazine is an FDA-approved nonopioid veterinary tranquilizer, used as a sedative and pain reliever for animals. It is not approved for use in humans. On the illicit drug market, xylazine is known as “tranq” or “tranq dope.” The drug itself produces powerful sedative effects in people similar to that of opioids, such as heroin, fentanyl, and oxycodone "oxy." When combined with opioids, xylazine increases the duration of the user’s euphoric effects.

The increasing prevalence of tranq dope

While the ongoing opioid epidemic has been well within the public consciousness for some time now, the arrival of xylazine on the scene has been a relatively new development. The results of a Philadelphia study show that xylazine was involved in 2% of opioid-related overdose deaths between 2010-2015. In 2019, 1 in 3 fatal overdoses involved xylazine.2 The Philadelphia Department of Public Health says 90% of fentanyl samples tested in 2021 contained xylazine.3

The issue is not just a Philadelphia problem, either. A 2022 study examining 10 places across the US found that xylazine-related overdose deaths rose from 0.36% in 2015 to 6.7% in 2020.4 Additionally, a 2019 report from the Centers for Disease Control and Prevention suggests xylazine-related overdoses may be undercounted, as testing for xylazine is not yet standard.5 Taken together, it appears the tranq dope trend is headed in an alarming direction.

Preventive measures

How can veterinary professionals help? While, xylazine is not currently a DEA-scheduled controlled substance under the Controlled Substances Act, the FDA recommends clinics that stock xylazine proactively take measures to monitor and track the drug to reduce the risk of diversion.1


  1. FDA alerts health care professionals of risks to patients exposed to xylazine in illicit drugs. News release. US Food and Drug Administration. November 8, 2022. Accessed December 16, 2022. https://www.fda.gov/drugs/drug-safety-and-availability/fda-alerts-health-care-professionals-risks-patients-exposed-xylazine-illicit-drugs
  2. Johnson J, Pizzicato L, Johnson C, Viner K. Increasing presence of xylazine in heroin and/or fentanyl deaths, Philadelphia, Pennsylvania, 2010-2019. Inj Prev. 2021;27(4):395-398. doi:10.1136/injuryprev-2020-043968
  3. Xylazine (Tranq). Philadelphia Department of Public Health. Accessed December 16, 2022. https://www.substanceusephilly.com/tranq
  4. Friedman J, Montero F, Bourgois P, et al. Xylazine spreads across the US: A growing component of the increasingly synthetic and polysubstance overdose crisis. Drug Alcohol Depend. 2022;233:109380. doi:10.1016/j.drugalcdep.2022.109380
  5. Kariisa M, Patel P, Smith H, Bitting J. Notes from the Field: Xylazine Detection and Involvement in Drug Overdose Deaths - United States, 2019. MMWR Morb Mortal Wkly Rep. 2021;70(37):1300-1302. Published 2021 Sep 17. doi:10.15585/mmwr.mm7037a4
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