Tranq Has Been Found in the Drug Supply in Almost Every State. And Now, It’s Across the Pond.

Xylazine, also known as “tranq,” is apparently wreaking havoc in the United States. Health departments have detected the substance in black-market fentanyl in New Mexico, California, West Virginia, and—well, almost every state. It’s been associated with overdose deaths in Philadelphia and elsewhere across the country. It has also crossed the ocean: A new study from King’s College London shows that xylazine is turning up in fake marijuana vapes, knockoff codeine, and Valium pills.

Veterinarians use xylazine on its own for sedation, muscle relaxation, and analgesia. It is approved by the Food and Drug Administration, but only for those cases and explicitly only for use in animals. When it’s mixed with fentanyl and used by humans, it can make for a dangerous combination. In fact, many media outlets have started call it a “zombie drug” because of the effects it can have: It can sedate its users, and can lead to large, rotting wounds if used frequently.

Here, we break down what’s happening, the main concerns that experts have about its prevalence, and why they say this scary-sounding drug isn’t the main thing they’re worried about.

If It’s for Animals, How Does It Get Into Fentanyl?

Drug dealers have been mixing it with heroin since at least the early 2010s, says Jeanmarie Perrone, the director of the Center for Addiction Medicine and Policy at the University of Pennsylvania, “but it was pretty clinically silent, perhaps because it was in lower concentrations than what we’re seeing now.” Basically: It went under the radar for a while. And now it’s being added to opioids.

Why … Would Anyone Add It at All?

Simple logistics play a role here: Adding something to fentanyl makes it possible to administer. A typical dose of fentanyl is in the sub-milligram range, essentially a pinhead amount. “If I sold you that, you couldn’t see it, you couldn’t use it,” explains Lewis Nelson, a medical toxicologist and chair of the Department of Emergency Medicine at Rutgers New Jersey Medical School. Mixing these microscopic amounts with something allows users to keep the small doses.

Usually, that something is sugars and starches. Xylazine, as a mix-in, has effects of its own. It’s often called an adulterant because it’s added with intentionality—it doesn’t just carry the fentanyl, it adds potentially appealing psychoactive properties. Xylazine can bolster the effects of opioids. “It’s basically sought to increase the overall euphoria or high that’s experienced with fentanyl,” says Kim Janda, a professor in chemistry and immunology at Scripps Research Institute in California.

OK, but Other Stuff Is Happening. What Happens When Xylazine Has Negative Effects?

The main adverse effect of xylazine goes back to its intended purpose: sedation. Xylazine has a faster onset of sedation than fentanyl, says Nelson. That sedation is commonly compared to being very very drunk, to the point where people don’t feel comfortable or in control of their body anymore, explains Claire Zagorski, a graduate research assistant at the University of Texas who recently co-authored a paper on reducing the harms of xylazine.

And being sedated for a really long time can cause some health problems.

“We are seeing folks that are getting bed sores, for example, just because they aren’t moving for hours on end,” says Zagorski. “It’s causing this damage and breakdown of the skin.”

Users also report skin ulcers, and not just a little pimple: In extreme cases, people lose chunks of tissue on their arms and legs because of it. Those who use drugs intravenously can develop infections, so that isn’t necessarily something new, but the way these wounds look and progress is very different, says Perrone.

Researchers aren’t exactly sure what’s causing the wounds, but Perrone suggests it could have to do with frequency of use. Lots of injections can lead to scabs that itch, and itching can lead to wound progression. “People with more occasional use tend not to have the wounds,” she adds.

Another theory is that these wounds are directly related to xylazine’s ability to constrict blood vessels, making it hard for blood to pass through tissue. Zagorski thinks it seems unlikely that the wounds are behaviorally driven, as there are black areas of dead tissue at places like users’ fingers and toes, again suggesting it could have to do with poor blood flow. But again, experts aren’t sure.

Is It As Deadly As Fentanyl?

Probably not. There isn’t really good data on fatality rates due to use in the illegal drug supply. One of the things that muddies the picture is that xylazine is rarely found on its own. Police in Seattle did recently find it being sold for the first time as a standalone pill, but in most cases it is used in conjunction with fentanyl or other opioids. And while there are many reports of “xylazine-associated” or “xylazine-involved” deaths, that doesn’t necessarily mean that xylazine was the direct killer, says Nelson.

But there is reason to think that xylazine isn’t the direct culprit. Zagorski points out that there are examples of people who work in the veterinary world who have overdosed on just xylazine. Even in those cases, it was generally not fatal. One very important difference between xylazine and fentanyl: “It doesn’t shut down that drive to breathe like opioids do,” she says.

If It’s Not Fatal, What Are Some of the Main Concerns?

Many of the people who are taking xylazine-laced fentanyl are unhoused. “It’s so saturated into the opioid supply,” Zagorski says. “So we’re finding this whole new spate of problems related to people being sedated, particularly if they’re unhoused and they can’t get somewhere safe to be sleepy.”

Not to mention, the wounds present a major issue during treatment. “Facilities decline patients because of their wounds, which leads to a bigger treatment gap and progression of wounds because of that barrier of waiting for a bed somewhere where someone can handle your wound problem,” says Perrone. If wounds are left untreated, it can lead to infection and further problems down the line.

I’ve Heard That Narcan Does Not Work on Tranq. That Seems Bad.

When people overdose on opioids, they take so much that it can stop their breathing. Naloxone, also known by its brand name, Narcan, essentially blocks the receptor that opioids act on, getting them to breathe again. However, xylazine isn’t an opioid. “Naloxone specifically talks just to opioid receptors,” says Zagorski, “so it’s like the wrong key in a lock.”

But because most products are a combination of both xylazine and fentanyl, it’s still worthwhile to administer Narcan to try to reverse the opioid effects. “If I give you naloxone, it will make you breathe again,” Nelson explains. It’s just that if there’s Xylazine in the mix, “it will not wake you up.”

If Narcan has already been administered, Zagorski encourages people to shake the person, call their name, rub their chest, and try to get them to wake up from the sedation.

Is There a Way to Test for Xylazine? And Is There a Treatment?

Yes, there are test strips that use the exact same kind of technology as pregnancy tests. But the problem is that given the prevalence of xylazine in the illicit drug supply, it might be hard to find a product that doesn’t have any, says Nelson.

In terms of treatment, Janda is currently working on a vaccine to block xylazine’s sleep-inducing effects. Janda and his team recently published a paper suggesting that their vaccine could reverse xylazine-induced behavior in mice, and are hoping to replicate findings in humans. But an actual vaccine is years away.

Some patients have also described xylazine withdrawal syndrome, which researchers are still trying to parse. “We’re still looking to characterize that and see how it might need to be treated differently than fentanyl,” says Perrone.

How Worried Should I Be About This?

If you’re not a drug user, your risk is quite low. It’s not the kind of thing that can affect you if you happen to be close to it. “If you touch it and lick your hand, that’s a problem,” Nelson says.
“But just the mere presence in space that you’re in, ambient exposure, is not a problem.”

Interestingly enough, Nelson says some data suggests xylazine has a protective factor. People who present in hospitals with fentanyl and xylazine have a lower rate of requiring CPR and cardiac arrest. And, Nelson says, it probably does not increase addiction.

As with any emerging health crisis, experts emphasized the picture is still forming and more research is needed. But as it stands right now, they see fentanyl as the larger issue.

“You see headlines that xylazine is the most dangerous drug in the world,” Nelson says. “In reality, the 800-pound gorilla here is fentanyl. Xylazine is just a bystander.”