Physicians Warn: New Drug Overdose Threat Contains Veterinary Tranquilizer Xylazine


Overdose Antidote Naloxone Ineffective Against Drug for Animals

Sept. 7, 2023 

Xylazine, a tranquilizer used in veterinary medicine, is appearing in illicit street drugs with fentanyl, compounding the dangers of the opioid overdose epidemic. Xylazine, also called “tranq” according to the U.S. Drug Enforcement Administration, is used to tranquilize animals. It is not approved for human use and has killed people who have taken the drug.

“Xylazine is a sedative that slows down the respiratory system, making it difficult to breathe, especially when mixed with other drugs like opioids,” said Michael Sprintz, DO, who specializes in treating chronic pain and addiction. Dr. Sprintz is a member of the Texas Medical Association (TMA) Committee on Behavioral Health and the Texas Pain Society.

“Not only is the drug harmful to humans, naloxone – a widely used antidote for opioid overdoses, including fentanyl – does not work on xylazine,” Dr. Sprintz said.

Naloxone was recently made available over the counter.

Illicit fentanyl deaths involving xylazine nationwide jumped from 3% in January 2021 to 11% in June 2022, a 276% increase. The Texas Department of State Health Services says four people have died from xylazine-related overdoses in West Texas alone.

Austin emergency physician Daniel Walk, MD, has seen xylazine overdose cases in his emergency department.

“I've already experienced one mass casualty event at my emergency room within the past year, poisoning dozens of Austinites, leading to some deaths and at least one patient on life support,” said Dr. Walk, a member of the TMA Committee on Emergency Services and Trauma.

Restricting a person’s ability to breathe is only one of xylazine’s harmful effects.

“Chronic users of xylazine frequently show severe skin wounds and ulcers caused by the drug’s ability to decrease the blood flow of small vessels, which kills that tissue,” said Dr. Sprintz. “These ulcers can appear anywhere on the body.”

Xylazine overdoses can be difficult to identify because they mimic opioid overdoses.

Despite naloxone’s ineffectiveness against xylazine, physicians say people helping an overdose victim should administer it regardless and call 911 immediately, because the drug could still help. “Since xylazine is added to illicit drugs laced with other opioids like fentanyl, naloxone will at least help reverse the opioid component of the overdose and could make the difference between life and death,” Dr. Sprintz said.

“However, if xylazine is involved, then additional medical intervention will be required.”

“Prompt emergency medical care is the best chance patients have to not die or become permanently disabled in the case of an overdose from xylazine,” Dr. Walk said.

To counter the sudden rise of xylazine in the illicit drug supply, Dr. Sprintz recommends testing for the drug in overdoses. According to the U.S. Food and Drug Administration, routine toxicology screens do not detect xylazine, and additional analysis is required to test for the drug in overdose cases.

Dr. Sprintz also warns it is important to not “consume any drug that is not specifically prescribed to you by a health care professional licensed to prescribe that medication.” He said taking even one pill from a friend or acquaintance can be deadly if it is laced with fentanyl and/or xylazine or any other dangerous chemicals found in drugs bought on the street.

As Illicit drugs are rapidly evolving to become more deadly, Dr. Walk recommends anyone struggling with addiction get the help they need to overcome the problem.

“I've seen too many promising lives, including personal friends, end abruptly or be crippled due to illicit drugs. Users have no guarantee that what they think they're buying isn't in whole or part a deadly chemical.”


TMA is the largest state medical society in the nation, representing more than 57,000 physician and medical student members. It is located in Austin and has 110 component county medical societies around the state. TMA’s key objective since 1853 is to improve the health of all Texans.

TPS is a 501c6 nonprofit organization that represents over 350 pain specialists in Texas. It is the largest state pain society in the nation.


 TMA Contacts:  

Brent Annear (512) 370-1381;

Swathi Narayanan (512) 370-1382;

 TPS Contact:

Krista DuRapau (512) 535-0010;

Last Updated On

September 18, 2023

Originally Published On

September 07, 2023

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