Southern Nevada health officials are warning that medetomidine, a powerful veterinary sedative known as "rhino tranq," has been found in the Las Vegas-area illicit drug supply, often mixed with fentanyl. Since July 1, 2025, five positive samples have been confirmed, though medetomidine still accounts for less than 1% of all samples collected since September 2024.
In a press release, District Health Officer Dr. Cassius Lockett said, "The detection of medetomidine in our local illicit drug supply is a serious and evolving public health concern." Health officials stress that naloxone should still be administered for opioid overdoses, but rescuers must prioritize rescue breathing and call 9-1-1, as medetomidine can cause prolonged deep sedation unaffected by naloxone, according to Southern Nevada Health District.
What Is Rhino Tranq and Why It Matters
Medetomidine is a veterinary anesthetic similar to xylazine, but it has been reported to cause stronger and longer-lasting sedation, cardiovascular depression and severe withdrawal than earlier "tranq" drugs. As reported by STAT, jurisdictions across the United States have been flagging medetomidine in fentanyl mixtures, and clinicians say it makes overdose care more complicated. Laboratory analyses and industry reports, including a clinical update from Aegis Labs, show that medetomidine detections have climbed sharply in recent years.
How to Respond to a Suspected Overdose
The Health District advises that naloxone should be administered for any suspected opioid overdose, followed by rescue breaths at roughly one breath every five seconds and an immediate call to 9-1-1, because medetomidine's sedative effects are not reversed by naloxone. Clark County surveillance data cited by the agency showed a 50% increase in fentanyl deaths and an almost 42% rise in methamphetamine-involved deaths between September 2024 and August 2025, a backdrop that underscores the local risk. In its release, SNHD urged people who use drugs and clinicians to stay alert for unusually persistent sedation after naloxone is given and to seek emergency care.
Where to Get Test Strips and Help
Free fentanyl and xylazine test strips are available without a prescription at the Main Public Health Center pharmacy at 280 S. Decatur Blvd., and additional pick-up locations are listed on the district's substance-use dashboard, FOX5 reports. Local coverage from the Las Vegas Review-Journal highlights links to SNHD resources and the Post Overdose Team for people seeking treatment or harm-reduction services. If you come across someone who is breathing poorly or not at all, officials say to begin rescue breaths and call 9-1-1 while waiting for emergency responders.
