There’s a Wave Coming. No. It’s Here.

By Dr. Kent S. Hoffman, Co-Founder of AddictionHelp.com

Just when we began to understand the damage caused by xylazine in the fentanyl supply, something worse has already arrived.

It’s called medetomidine, or “Dex” on the street. And I’m here to say, plainly and urgently: this changes the game again.

Dex is a potent, dangerous veterinary sedative that is not approved for human use. It’s structurally similar to Precedex, a drug we use in hospitals to sedate patients during intensive care or short procedures. Dex slows the heart, lowers blood pressure, and induces deep sedation.

And now, it’s showing up with increasing frequency in the illicit fentanyl supply.

According to a detailed report published by Lev Facher of STAT News on May 1, 2025, Dex has already surpassed xylazine in prevalence in Philadelphia, found in up to 80% of fentanyl samples. It has also been detected in Florida, but without better surveillance, we don’t know how far this is spreading. And that’s a big part of the problem.

Naloxone Isn’t Enough Anymore

Let me be clear: Naloxone (Narcan) will reverse the opioid in fentanyl—but not the sedation of Dex.

Someone may receive naloxone and still remain unconscious. Their breathing may still be depressed. Their blood pressure may remain dangerously low. Their heart rate may not recover. These aren’t signs of Narcan failure. They’re symptoms of a non-opioid sedative doing what it’s built to do—except now it’s in the hands of street chemists.

As a physician, this is terrifying. As someone who’s spent his life treating people with opioid use disorder, I know how easily this could be misunderstood by both clinicians and families.

A Second Withdrawal—One We’re Not Ready For

There’s something else we need to talk about: Dex causes its own withdrawal.

Patients who have unknowingly been using Dex-laced fentanyl aren’t just opioid-dependent anymore. They are now also dependent on a potent sedative.

When they try to stop, they may not just experience typical opioid withdrawal. They may also develop rebound hypertension, severe agitation, and cardiovascular stress, effects that are essentially the reverse of what Dex does during intoxication.

This is uncharted territory for many Suboxone providers and outpatient programs, who are trained to treat opioid withdrawal but not withdrawal from alpha-2 adrenergic sedatives.

That knowledge gap could create real suffering and increase the risk of relapse.

So What Do We Do? Carefully, and With Data

Let me be cautious here.

While theoretical options are being discussed—like clonidine or even tapers using related sedatives such as Precedex or the veterinary reversal agent atipamezole—we do not yet have clinical research or clear guidance on how to treat Dex withdrawal in humans.

We need to study this urgently and not jump to conclusions. Until then, we must tread carefully.

New Tools Are Emerging—and We Need to Use Them

One bright spot: point-of-care test strips for Dex already exist.

Clinicians can use them alongside fentanyl test results to better understand what substances patients have been exposed to. But those results mean little if they’re isolated in individual offices.

That’s why I believe we need to establish state-level reporting systems—voluntary, de-identified databases where clinicians can report positive Dex findings. If we start collecting that data consistently, we might finally get a handle on where Dex is, how fast it’s spreading, and how many people it’s impacting.

Right now, we’re in the dark.

And in addiction medicine, darkness kills.

We’ve Been Here Before—But This Time, It’s Worse

We’ve seen how the street supply can evolve. Heroin to fentanyl. Fentanyl to xylazine. Now, xylazine to Dex.

Each shift leaves our systems scrambling to respond.

But Dex is different. Its effects are more potent, its presence is harder to detect, and its withdrawal is less understood. Every piece of this makes recovery harder, riskier, and more complex—not just for patients but also for families, providers, and first responders.

We need testing. We need research. We need education.

And most of all, we need to admit that we’re not ready for what’s already here.

About the Author:
Dr. Kent S. Hoffman is a board-certified addiction medicine physician and the co-founder of AddictionHelp.com. He has treated thousands of patients for opioid use disorder and works nationally to improve ethical standards and clinical outcomes in addiction care.