WASHINGTON — Federal health officials are warning about a powerful veterinary sedative showing up more frequently in the illicit drug supply.
The Centers for Disease Control and Prevention (CDC), in conjunction with the White House Office of National Drug Control Policy (ONDCP), has issued a health advisory on medetomidine, also known as “rhino tranq,” “mede,” or “dex.” The drug is not approved for human use but is used for sedation and pain control in animals, including dogs.
According to the CDC, medetomidine is being detected more often in law enforcement drug seizures, drug samples, and even wastewater testing, with the highest concentrations reported in the Northeast.
Health officials warn the drug can cause severe side effects, including profound sedation, slowed heart rate, and dangerously low blood pressure.
“Medetomidine represents a real threat to communities, and this once again reaffirms that the only safe level of illegal drug use is zero,” said Director of National Drug Control Policy Sara Carter in a press release.
People who regularly use the drug may also experience intense withdrawal symptoms if they stop, including high blood pressure, anxiety, nausea, vomiting, and changes in alertness. These symptoms can require emergency or intensive care.
“The public health community, as well as those who put themselves at risk of overdose due to illegal drug use, need to be aware of ever-evolving dangers,” said Carter.
The CDC says fentanyl is involved in most overdoses linked to medetomidine. In suspected overdoses, opioid reversal medications such as naloxone should still be administered.
Medetomidine, which is more potent and longer-acting than clonidine and xylazine, was first identified in the illicit drug supply in 2021. The CDC says it began appearing sporadically alongside fentanyl in several cities, including Chicago, Philadelphia, and Pittsburgh, between mid-2023 and mid-2024. By late July 2024, the drug had been detected in both seized drug samples and biological specimens from people using illicit opioids in at least 18 states and the District of Columbia.
Since then, its spread has accelerated. Reports submitted to the National Forensic Laboratory Information System (NFLIS), which tracks drug seizures analyzed by forensic labs, increased by 950%, rising from 247 reports in 2023 to 2,616 in 2024. That number climbed another 215% in 2025, reaching 8,233 reports.
Cases were most heavily concentrated in the Northeast and Midwest , followed by the South and the West.
More recently, from October 2025 through January 2026, medetomidine was detected every week in treated wastewater in at least one of 14 states participating in a national monitoring program, another sign that the drug’s presence is continuing to grow.
