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A new, more powerful sedative is entering the illicit drug supply and raising serious concerns for individuals, families, and healthcare providers alike. Its name is medetomidine, a drug commonly used in veterinary sedation under strict medical supervision. But now, it is appearing in street drugs, often unknowingly mixed with fentanyl, and contributing to complex, hard-to-reverse overdoses across the U.S.
In this article, we’ll explore what medetomidine is, how it compares to xylazine, the dangers it presents, and what people should know about treatment, including when Medication-Assisted Treatment (MAT) may be appropriate.
What Is Medetomidine, AKA ‘Rhino Tranq’?
Medetomidine (pronounced meh-deh-TOH-mih-deen) is a central nervous system depressant in a class of drugs called alpha-2 adrenergic agonists. It is FDA-approved for veterinary use as a potent sedative and pain reliever. A closely related medication, dexmedetomidine (brand name Precedex®), is used in human hospitals to sedate patients in intensive care.
However, medetomidine is not approved for human use outside of clinical settings, and it is not safe for recreational use, injection, or unsupervised consumption.
What Is Medetomidine Used For?
In clinical and veterinary settings:
- Medetomidine is used to sedate animals during surgery or procedures.
- Dexmedetomidine is used in hospitals to calm critically ill patients, often those on ventilators.
On the street, medetomidine is:
- Illegally added to fentanyl to intensify or prolong sedation
- Found in counterfeit pills or powders, often without the user’s knowledge
Medetomidine vs. Xylazine: What’s the Difference?
Xylazine, also known as "tranq," has been widely reported in the drug supply and is known for causing deep sedation and severe tissue damage. Now, medetomidine is rapidly replacing xylazine in many U.S. cities.
According to STAT News, medetomidine was found in 87% of fentanyl samples tested in Philadelphia by late 2024, up from just 29% six months earlier. Meanwhile, xylazine presence dropped to 42%.
Key Differences:
- Medetomidine is up to 200 times more potent than xylazine (BCCDC)
- Unlike xylazine, medetomidine does not cause skin wounds
- It causes stronger cardiovascular suppression and deeper sedation
- Both are non-opioid sedatives and do not respond to naloxone
What Are the Side Effects of Medetomidine?
Street users consuming medetomidine, often unknowingly, may experience:
- Extremely low heart rates (as low as 20 beats per minute)
- Respiratory depression
- Prolonged unconsciousness
- Initial high blood pressure followed by low blood pressure
- Dizziness, nausea, and confusion
- Hypothermia
- Effects lasting 90 minutes or longer, especially when combined with fentanyl or benzodiazepines
(Source: BCCDC Substance Info Sheet, Oct 2024; NPR)
Medetomidine Overdose: Why Naloxone Might Not Work
Because medetomidine is not an opioid, naloxone (Narcan®) does not reverse its effects. It may still help with the opioid portion of a mixed-drug overdose, but people may remain heavily sedated even after it is administered.
In overdose cases:
- Victims may have no pulse or breathing even after naloxone
- Emergency responders must provide oxygen, CPR, and immediate hospital transport
- Timely supportive care is essential
Medetomidine Withdrawal Symptoms Can Be Life-Threatening
According to addiction experts at the University of Pennsylvania, medetomidine withdrawal can be more dangerous than xylazine withdrawal (STAT News). It can cause sudden increases in heart rate and blood pressure, which may raise the risk of stroke or heart failure.
Common symptoms include:
- Severe agitation
- Sweating and shaking
- High blood pressure
- Elevated heart rate
- Potential damage to organs
What Is Medetomidine Called on the Street?
Street names for medetomidine are still emerging, but confirmed slang includes “Rhino Tranq” (rhino tranquilizer), “Dex” (from dexmedetomidine), and “Mede” (short for medetomidine). In most cases, it’s not sold on its own. Instead, it is typically mixed into fentanyl, heroin, or counterfeit pills, making it highly dangerous.
Is MATClinics Treatment Appropriate for Individuals Using Medetomidine?
MATClinics specializes in treating opioid, alcohol, and stimulant use disorders, and while medetomidine itself is not an opioid, it is increasingly being found in the illicit drug supply, often mixed into opioids and counterfeit pills.
Over the last two months, 8–12% of incoming MATClinics patients have tested positive for medetomidine. Our providers focus on treating the underlying opioid use disorder, even when medetomidine or other non-opioid substances are also present, offering evidence-based care to help patients safely begin recovery despite the risks in today’s drug supply.
MATClinics Offers:
- Suboxone® (buprenorphine/naloxone) treatment
- Sublocade® and Vivitrol® injections
- Therapy, psychiatry, and case management
- Support for complex polysubstance use
Patients experiencing repeated overdoses, difficult withdrawal, or mental health concerns related to medetomidine-laced opioids are encouraged to reach out.
What To Do If You Suspect Medetomidine Exposure
If someone shows signs of medetomidine exposure, including heavy sedation, slow breathing, or a low heart rate:
- Call 911 immediately
- Administer naloxone if available
- Perform rescue breathing or CPR if trained
- Request hospital transport
Once stabilized, the person can begin evidence-based, compassionate treatment at MATClinics. Our providers are trained to manage opioid-related complications, even when sedatives like medetomidine are involved.
Final Thoughts: Staying Ahead of a Changing Drug Landscape
The illicit drug supply is changing rapidly, and medetomidine is one of the most dangerous additions. It increases overdose risk, complicates withdrawal, and does not respond to naloxone.
While MATClinics does not treat sedative use disorders directly, we provide care for the opioid-related risks of medetomidine and offer comprehensive support for recovery.
If you or someone you know is struggling with opioid use in Maryland, contact MATClinics to get help today.
Sources
- British Columbia Centre for Disease Control (BCCDC). Medetomidine Substance Info Sheet, October 2024
- STAT News. “Sedative 'dex' is replacing 'tranq' and causing excruciating withdrawal”, May 2025
- NPR. “Gangs mix another potent sedative into U.S. street drugs causing 'mass overdoses’”, June 2024