What to Know About ‘Tranq,’ the Animal Sedative Infiltrating Street Drugs

Public health officials are sounding the alarm about xylazine, a substance that causes gruesome wounds and knocks users out for hours

Used needles and other paraphernalia on the ground
Public health officials are warning about xylazine, also known as “tranq” or “tranq dope,” an animal sedative that's infiltrating the nation’s illicit drug supply in substances such as heroin and fentanyl. Andrew Lichtenstein / Corbis via Getty Images

An animal sedative that’s harmful to human health is showing up in street drugs across the United States, and it appears to be spreading. The drug, called xylazine, causes severe skin wounds and knocks users out for hours at a time, leaving them vulnerable and exposed.

Public health officials say xylazine, also known as “tranq” or “tranq dope,” is infiltrating the nation’s illicit drug supply in substances such as heroin and fentanyl. It’s also becoming increasingly prevalent in overdose deaths.

A recent analysis by Brown University found xylazine in more than 40 percent of street drug samples in Rhode Island, reports ABC News’ Nicole Wetsman. Another recent study found the drug in 36 states and the District of Columbia. And in 2021, the most current data available, xylazine showed up in more than 90 percent of dope samples in Philadelphia.

One of the drug’s hallmarks in humans is the presence of gruesome wounds and decaying skin tissue called eschar, which can become infected and lead to amputation.

“The tranq dope literally eats your flesh,” says Brooke Peder, a 38-year-old tattoo artist in Philadelphia who has had a leg amputated due to an infected tranq wound, to the New York Times’ Jan Hoffman. “It’s self-destruction at its finest.”

In November, the U.S. Food and Drug Administration (FDA) warned health care professionals about the drug, which does not show up on routine toxicology screens and can be difficult to distinguish from opioid use. Since it’s not an opioid, xylazine may not respond to naloxone, a standard treatment for opioid overdoses.

The Bayer Company first developed xylazine in 1962, according to a November memo from the Drug Enforcement Administration (DEA). Ten years later, the FDA approved xylazine as a veterinarian-prescribed sedative and pain reliever for animals, reports the Times. Per the DEA, veterinarians use it to “calm and facilitate handling, perform diagnostic and surgical procedures, relieve pain or act as a local anesthetic” in various species, such as cattle, sheep, horses, dogs, cats, deer, rats and elk.

Drugmakers studied xylazine in humans for the same purposes but ended their clinical trials, because it caused severe low blood pressure and depressed the central nervous system. Veterinarians can use substances such as yohimbine hydrochloride and tolazoline hydrochloride to help reverse xylazine’s effects in animals, however, it’s not clear if these same substances are safe and effective among humans.

Though its exact origins are difficult to trace, people likely began using xylazine in Puerto Rico in the 2000s. The federal government has not listed xylazine as a controlled substance for humans or animals, which means drug enforcement officials have not been monitoring it for abuse. Hospitals don’t typically test for it, nor do some state medical examiners, per the Times.

Public health officials are still trying to get a handle on the drug, as well as how best to respond to it. Researchers have not widely studied xylazine’s effects on humans, and they don’t know why it’s causing such horrific wounds. Amid rising fentanyl overdoses, public health experts are also trying to figure out how best to treat overdoses in which xylazine may have played a role, reports STAT News’ Andrew Joseph.

“It’s devastating at this point, and to add this on top of the overdose crisis, it is just fuel to an already out-of-control fire,” says Corey Waller, chief medical officer at BrightView, which runs addiction treatment centers across the country, to Spectrum News 1’s Sheena Elzie.