Published: 07/24/2026 | Author: Nikki Wisher

Nearly 17% of people testing positive for fentanyl also test positive for xylazine, a veterinary sedative with no approved use in humans, according to a national study of urine drug tests. The number is climbing, especially in parts of the country where xylazine barely showed up just two years ago.

The Opioid Crisis in Wastewater

Researchers analyzed 42,307 urine drug tests collected from patients in primary care, behavioral health, and substance use treatment settings between March 2023 and September 2025. All tested positive for fentanyl. Of those, 7,156 samples, or 16.91%, also tested positive for xylazine.

The trend lines tell the real story. In the Eastern United States, where xylazine has circulated for years, positivity climbed from 11.11% to 19.63% over the study period. The numbers peaked at 42.31% of samples in a single month. 

In the West, where xylazine essentially had no presence at the start of the study, positivity rose from 0% to 13.46%. It’s a sign that the drug has actively spread into markets that hadn’t seen it before.

Testing also found that people whose samples tested positive for heroin were more than twice as likely to also test positive for xylazine. Higher fentanyl concentrations also strongly linked to higher odds of xylazine detection. In other words, xylazine doesn’t show up at random. It travels with the heaviest exposure to other substances.

Driving the Trend

Interestingly, while more people test positive for xylazine, the actual concentration found in positive samples has dropped. In eastern states like New York, median xylazine levels fell sharply after an early 2023 peak. Researchers think manufacturers and distributors may be adjusting how much xylazine they mix into fentanyl, whether in response to reports of severe skin wounds and prolonged sedation, or because new state laws and restrictions on veterinary xylazine supplies make it harder to source in bulk.

That’s a mixed signal for people who use drugs. More positive tests means more people are being exposed to xylazine somewhere in their supply, even if any individual dose tends to be smaller than it once was.

Fentanyl’s Role

Fentanyl remains the driver of the opioid crisis, and this study only counted samples where fentanyl was already present. Now, xylazine rides along inside a fentanyl supply that’s already dangerous. Since xylazine isn’t an opioid, naloxone doesn’t reverse its sedative effects, so more people testing positive for both drugs together matters for how overdoses get treated on the ground.

Researchers also flagged medetomidine, a chemically similar veterinary sedative. Medtomidine is starting to show up as a possible replacement for xylazine in some markets, but wasn’t part of this study’s testing panel. That means the true scope of veterinary sedatives mixed into the fentanyl supply right now may be larger than these numbers capture.

Harm Reduction and Treatment Works

People who use drugs have a practical takeaway. A fentanyl test strip might confirm fentanyl but says nothing about what else it contains. Xylazine-specific test strips exist and are increasingly available through harm reduction programs, though access still varies by state and city.

Naloxone remains essential and should be carried by anyone using opioids or spending time with someone who does. Since xylazine keeps a person sedated even after naloxone reverses the opioid component of an overdose, calling emergency services after administering naloxone matters more than ever when xylazine exposure is a possibility.

Medication for opioid use disorder (MOUD), including methadone and buprenorphine, remains a first-line treatment option regardless of what adulterants are present in someone’s supply. 

Narcotics Anonymous meetings also offer ongoing peer support for people building a recovery plan around opioid use, whether or not they are using MOUD alongside it.

NA Still a Top Option

NA meetings remain a critical first step to recovery, from either fentanyl or any other substance. Meetings are free, confidential, and build fellowship that lasts a lifetime, through the good times and bad.

Getting started is easy. Just dial 800-934-1582(Sponsored) to speak with an expert about local opioid addiction treatment options. Or browse our directory to find chapters anywhere across the United States.