The Centers for Disease Control and Prevention (CDC), in collaboration with the White House Office of National Drug Control Policy, recently issued a Health Advisory about the spread of medetomidine in the illicit drug supply.
Medetomidine is a non-opioid sedative, often mixed with fentanyl. It’s informally known as “rhino tranq,” “mede,” and “dex.” This drug is extremely dangerous. A study cited by the Philadelphia Department of Health found that medetomidine is 100–200 times more potent than xylazine, a k a “tranq”––a street drug known for causing ugly lesions and open wounds in users. The CDC warned that medetomidine can cause sedation, bradycardia, and hypotension, adding that it can lead to “severe withdrawal” (though it does not lead users to develop wounds). The symptoms of withdrawal from medetomidine include hypertension, anxiety, tachycardia, chest pains, tremors, nausea, vomiting, and fluctuating alertness.
Medetomidine emerged in the drug supply in 2021. The number of samples of medetomidine reported to the DEA increased from 247 in 2023 to 2,616 in 2024 and 8,233 in 2025––a 33x increase between 2023 and 2025. Most of these reports were in the northeast, with the fewest in the west. The drug has been associated with “overdose clusters,” according to the CDC. An incident in Chicago in 2024 identified 12 confirmed, 26 probable, and 140 suspected overdoses involving medetomidine. Prior to this, medetomidine had not been identified in Chicago’s drug supply. Additional clusters were reported in Philadelphia and Pittsburgh in 2024.
More broadly, medetomidine appears to be displacing xylazine in the illicit drug supply. In Philadelphia in May 2024, 97% of fentanyl samples contained xylazine and 29% contained medetomidine. By November 2024, this pattern had inverted, with 87% of fentanyl samples containing medetomidine and 42% containing xylazine. Medetomidine has been detected in 46 overdose deaths in Philadelphia since May 2024.
Sara Carter, the director of the Office of National Drug Control Policy, said, “medetomidine represents a real threat to communities, and this once again reaffirms that the only safe level of illegal drug use is zero.” That’s exactly right.