Medetomidine in the U.S. Illegal Fentanyl Supply Increasing Risk for Overdose and Severe Withdrawal Syndrome
Apr. 2, 2026
At a glance
Distributed via the CDC Health Alert Network
April 2, 2026, 10:00 AM ET
CDCHAN-00527
This is an official Health Advisory
Summary
The Centers for Disease Control and Prevention (CDC), in conjunction with the White House Office of National Drug Control Policy (ONDCP), is issuing this Health Advisory to notify public health professionals, clinicians, laboratorians, and people at risk for overdose about increasing reports from U.S. jurisdictions detecting medetomidine in the illegal drug supply and a severe withdrawal syndrome due to medetomidine exposure. Medetomidine (also known as 'rhino tranq,' 'mede,' or 'dex') is not approved for human use but is approved for sedation and analgesia in dogs. Its dextro-isomer, dexmedetomidine, is approved for procedural sedation in humans. Medetomidine has been increasingly detected in law enforcement drug seizures, drug product and paraphernalia samples, and in wastewater samples, with the highest concentrations in the Northeast region. Testing of illegal drug samples and clinical specimens has identified racemic mixtures of levomedetomidine and dexmedetomidine isomers without the preservatives commonly found in medical or veterinary formulations, making diversion of pharmaceutical products unlikely. Since pharmaceutical-grade products contain only dexmedetomidine, these findings suggest medetomidine is being synthesized in clandestine laboratories.
Medetomidine can cause profound sedation, bradycardia, and hypotension. Stopping medetomidine following regular use may lead to severe withdrawal, similar to clonidine withdrawal, with symptoms including hypertension, anxiety, nausea, vomiting, and fluctuating alertness, that can require emergency or intensive care. Because fentanyl is involved in most overdoses involving medetomidine, opioid overdose reversal medications (OORM; e.g., naloxone) should be administered to restore normal breathing in suspected overdoses.
Public health professionals can use syndromic surveillance to detect medetomidine-related intoxication or withdrawal signs and symptoms. Public health and public safety agencies and clinicians should collaborate to monitor the local drug supply and share timely information to align clinical and public health action. Clinicians should consider medetomidine in suspected opioid overdoses with prolonged sedation unresponsive to OORM administration, consult a toxicologist or poison control at 1-800-222-1222, and report unusual cases to the appropriate health department.
Background
Despite declines in U.S. drug overdose deaths since 2022 that continued in 2025, the illegal drug supply remains unpredictable. Illegally made fentanyl continues to be involved in most overdose deaths and is frequently mixed with other drugs, such as benzodiazepines or xylazine. Medetomidine, an alpha-2 adrenergic agonist sedative, more potent and longer-acting than clonidine and xylazine, was first identified in the illegal drug supply in 2021 and began appearing sporadically with fentanyl in multiple jurisdictions including Chicago, Philadelphia, and Pittsburgh from mid-2023 to mid-2024. By late July 2024, medetomidine had been detected in drug samples and biological specimens from people who use illegal opioids in at least 18 states and the District of Columbia.
https://www.cdc.gov/han/php/notices/han00527.html