Federal health agencies have issued a warning about medetomidine, a dangerous veterinary sedative entering the illicit drug market.
Commonly called “rhino tranq,” the drug is being detected alongside fentanyl at alarming rates. Incidents rose from 247 in 2023 to over 8,200 in 2025-a spike of more than 3,000%.
Medetomidine causes profound sedation and life-threatening withdrawal symptoms. Unlike fentanyl, it does not respond to naloxone (Narcan), used to reverse opioid overdoses.
The CDC reports the drug has been identified in at least 18 states, primarily across the Northeast and Midwest. Co-occurrence with fentanyl increases clinical complexity and risk of severe outcomes.
Symptoms include extreme drowsiness, slow heart rate, low blood pressure, and respiratory depression. Withdrawal can trigger severe hypertension, agitation, and neurological issues, often requiring ICU-level care.
A 2024 outbreak in Chicago involving medetomidine led to over 175 suspected overdoses, with 16 hospitalizations and one fatality.
Experts warn current toxicology tests do not routinely detect medetomidine, delaying diagnosis and treatment. Clinicians are urged to consider broader toxicity models and enhance coordination with public health entities.