American Society of Addiction Medicine issues first national guidance on medetomidine withdrawal
The American Society of Addiction Medicine this week issued the first U.S. national guidance on recognizing and treating people exposed to medetomidine, a potent sedative now mixed into illicit opioids. The document is framed as “considerations” rather than formal guidelines because larger studies have not yet confirmed what clinicians have inferred from practice.
Doctors first noticed the drug in Philadelphia’s street supply in spring 2024, after a weekend cluster of overdoses left patients unusually sedated and bradycardic even after naloxone. None of those patients died, and most went home the same day. The danger became clearer in autumn, when people developed severe withdrawal after repeated exposure. Jeanmarie Perrone, an emergency physician who directs the Penn Medicine Center for Addiction Medicine and Policy and co-authored the guidance, said withdrawal—not the initial overdoses—has caused the worst problems.
Because medetomidine is almost always used with illicit opioids, naloxone remains the first step in overdose, though patients may stay unresponsive after breathing resumes. Low heart rate and blood pressure from acute intoxication can often be managed with intravenous fluids and basic care. Withdrawal typically begins with nausea and vomiting, without the diarrhea of opioid withdrawal; clonidine, an alpha-2 agonist like medetomidine and xylazine, is the recommended first treatment. If pills cannot be kept down, soaring blood pressure and a rapid pulse within hours may require intravenous dexmedetomidine (Precedex). Kory London, an emergency and addiction specialist at Thomas Jefferson University who did not write the paper, said coming off medetomidine can require intensive care and doses of clonidine and dexmedetomidine far higher than those used when xylazine first adulterated fentanyl.
Unlike xylazine, medetomidine does not appear to cause the same severe wounds, but it is a stronger sedative. By the end of 2025 it had been found in at least 18 states. Co-author Michael Lynch, a medical toxicologist at the University of Pittsburgh Medical Center, stressed that local supply testing matters because symptoms can mimic other illnesses, including sepsis.
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