Health and government leaders are sounding the alarm about a dangerous substance found in the illegal drug market. The Centers for Disease Control and Prevention (CDC) and the White House’s Office of National Drug Control Policy (ONDCP) released an advisory on Thursday, warning that medetomidine, a veterinary sedative, is now being detected in fentanyl.
Medetomidine, often referred to as “rhino tranq” or simply “mede,” is known for causing heavy sedation. It is an alpha-2 agonist that impacts the nervous system similarly to other veterinary sedatives, like xylazine, and can lead to serious withdrawal symptoms.
This alert comes after a review of various data, including drug testing, clinical case reports, and investigations into overdoses. Reports showed a staggering increase in the number of medetomidine cases: from just 247 in 2023 to over 8,200 in 2025, indicating a rise of more than 3,000%. Alarmingly, about 98% of the samples that tested positive for medetomidine also contained fentanyl.
The drug has been found in at least 18 states, with a concentration primarily in the Northeast and Midwest. Dr. Adam Scioli, the Chief Medical Officer at Caron Treatment Centers in Pennsylvania, expressed concern over this “rapidly evolving development” in the illegal opioid market.
He explained that the presence of medetomidine alongside fentanyl complicates the treatment of overdoses, making it harder for healthcare providers to manage withdrawal and overdose situations. Medetomidine isn’t usually picked up in standard toxicology screenings, which increases the risk of it going unrecognized in medical situations.
Unfortunately, naloxone (Narcan), well-known for reversing opioid overdoses, does not work against medetomidine’s sedative effects. Dr. Scioli noted that while naloxone is key for opioid-related respiratory issues, it won’t alleviate the sedation caused by medetomidine.
The initial effects of medetomidine can include deep sedation, slow heart rate, low blood pressure, and respiratory troubles, especially when mixed with fentanyl. Withdrawal symptoms can begin just hours after use, potentially escalating quickly and requiring intensive medical care.
In one alarming case from May 2024, medetomidine was linked to a group of overdoses in Chicago, resulting in over 175 incidents, hospitalizations, and at least one fatality.
The CDC admits that the surveillance has limitations, acknowledging that their data might not fully represent the situation due to small sample sizes and the possibility of contamination. They emphasized the need for careful assessment going beyond typical opioid treatment models, stressing the importance of collaboration among various health sectors.
Dr. Scioli highlighted that this situation demonstrates the necessity for adaptive and sophisticated addiction care that supports long-term recovery rather than just focusing on immediate stabilization.
