The Drug Enforcement Administration recently issued a warning about a drug that’s making the nation’s deadly opioid epidemic even deadlier. It’s xylazine, a powerful veterinary sedative that’s increasingly being found in illicit fentanyl supplies around the U.S.

The agency’s lab system found xylazine in 23% of fentanyl powder and 7% of fentanyl pills it had seized in 2022. Policymakers are aware of the lethal mixture — also called tranq — but they’re moving too slowly to contain it.

Xylazine is a scary addition to the illicit medicine cabinet. The drug is relatively cheap and has longer-lasting effects than fentanyl alone, and can cause skin to slough off, forming deep wounds that can become so badly infected they require amputation. Users can lose chunks of time, blackouts that put them at risk of rape and theft. And its growing presence in the fentanyl supply is making it even harder to treat addiction.

Increasingly adulterated

It’s also a scary sentinel of a complicated future for drug treatment in the US. Illicit drug supplies in the U.S. are increasingly being adulterated with multiple substances. If we don’t get a handle on the problem, the already gargantuan challenge of opioid use disorder will become that much harder to address.

Xylazine is already complicating efforts to treat overdoses. Narcan has helped prevent deaths from fentanyl, but xylazine acts on different receptors than opioids, and there’s currently no way of reversing its effects. Someone exposed to both drugs can see their heart rate drop and breathing slow to deadly levels.

And it’s making it even harder to help people seeking treatment for opioid addiction. Fentanyl had already made withdrawal more difficult. Although it’s a short-acting drug, it can stick around in the bodies of longer-term users, likely due to its ability to absorb into fat cells. A user must wait for her system to clear the drug before she can start treatment with buprenorphine, which eases withdrawal symptoms and opioid cravings.

Xylazine also absorbs into fat cells, and adding it into the equation seems to make the problem worse. “We’re looking at four, five days” before the drug is cleared, says Ryan Alexander, the medical director for substance use services at The McNabb Center in Knoxville, Tennessee. “That’s really making treatment more challenging.” During that period, withdrawal from xylazine can cause high blood pressure, increased heart rate and agitation. Alexander says some people get so frustrated that they simply leave.

“Imagine being in a fight or flight state for days and days and days. Your thinking isn’t clear, you’re not going to wait for the opioid withdrawal,” says Nabarun Dasgupta, an epidemiologist who studies drugs and infectious diseases at the University of North Carolina’s Injury Prevention Research Center.

People working on the front lines of addiction need more and better real-time information about xylazine in local supplies. While the drug has been identified in samples from nearly everywhere in the U.S., its presence is more prevalent in some states than others.

Test for contamination

Another key component of harm reduction is testing illicit drugs for contamination. Drug-checking efforts may once have been politically controversial, but at least at the state level, Democrats and Republicans alike increasingly recognize their value. Yet nationwide access is still far too limited. Newly available xylazine test strips would help drug users check their own supply, though currently they are expensive and hard to find.

Policymakers are taking steps to try to keep xylazine out of other drugs. States where the drug has already wreaked havoc are trying to stem the influx by listing it as a controlled substance. Congress, meanwhile, is considering a federal classification that would in theory give regulators and law enforcement agencies more power to crack down on people possessing it and diverting it from veterinary use.

Those efforts are helpful, but officials need to move faster to address not just supply, but treatment, too. Provisional data from the Centers for Disease Control and Prevention suggests overdose deaths from synthetic opioids declined in 2022 from their 2021 peak as states got a better handle on the opioid epidemic. We can’t let xylazine undermine that progress.

And as the country considers where to put its time and resources, it’s worth remembering that even if xylazine magically disappeared tomorrow, something else — potentially something worse — is likely waiting in the wings to replace it.

‘Polysubstance’ use

“It’s good we’re talking about xylazine because xylazine is important,” Joseph Friedman, an addiction researcher at UCLA, who has helped quantify the spread of the sedative in the U.S.. “But we shouldn’t look at a tree and miss the forest. Fentanyl has ushered in a massive wave of polysubstance use.”

Dasgupta, the UNC researcher, noted that his lab’s street-drug surveillance has already revealed new adulterants popping up in samples from Ohio, North Carolina and New York. He worries that another, much more potent veterinary sedative called dexmedetomidine, which is also approved to treat schizophrenia in humans, could be the next substance to gain a foothold.

Staying on top of these threats will require catching new substances right as they’re emerging — and not after people are already dying because of them. The next drug to come along could have just as sinister an impact on a society already struggling to get a handle on opioid addiction.

Lisa Jarvis is a Bloomberg Opinion columnist covering biotech, health care and the pharmaceutical industry. Previously, she was executive editor of Chemical & Engineering News.