04/04/2026
Medetomidine in the U.S. Illegal Fentanyl Supply Increasing Risk for Overdose and Severe Withdrawal Syndrome
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.
