Medetomidine: What to Know About the Powerful Veterinary Sedative Showing up in the Drug Supply

Medetomidine is appearing more often in illegal drugs, usually mixed with fentanyl. People may not know they're taking it, so it's important to understand the risks and how to respond to an overdose.

What is medetomidine? 

Medetomidine is a powerful animal sedative approved only for veterinary use. It can cause extreme sleepiness, a slow heart rate and low blood pressure. It isn’t an opioid. It’s similar to xylazine, sometimes called tranq, but the CDC reports that medetomidine is stronger and lasts longer. 

It was first detected in the U.S. illegal drug supply in 2021 and is now most often found with fentanyl, sometimes without a person's knowledge.

How widespread is medetomidine? 

The number of federal laboratory reports rose from 247 in 2023 to 2,616 in 2024 and 8,233 in 2025. These are tested drug samples, not people or overdoses, but the sharp increase shows that medetomidine is spreading. 

How does medetomidine affect the body? 

A person who has taken medetomidine may experience: 

• Prolonged, extreme sleepiness or deep sedation 

• Slow or irregular breathing 

• A slow heart rate 

• Low blood pressure 

• Dizziness, confusion, nausea or blurred vision 

Does naloxone work on medetomidine overdoses? 

Naloxone can't reverse medetomidine because it isn't an opioid. But it's usually mixed with opioids, especially fentanyl. That's why naloxone should still be given whenever an overdose is suspected. It can reverse the opioid part of the overdose and won't harm someone if no opioids are present. 

The person may still be deeply asleep after receiving naloxone, even if the opioid overdose has been reversed. Focus on whether they're breathing normally, not only on whether they wake up. 

An overdose is a medical emergency. Give naloxone and call 911, even if the person begins breathing again. 

What should you do if you suspect an overdose? 

• Call 911 immediately and administer naloxone if it’s available. 

• Lay the person on their back. 

• Insert the naloxone nozzle into one nostril and press the plunger. 

• If the person doesn’t respond within two to three minutes, give another dose. 

• Stay with them until emergency services arrive. They may remain deeply asleep because naloxone doesn’t reverse medetomidine. 

Learn more about how to respond to an overdose. 

What does medetomidine withdrawal look like? 

Someone who regularly uses substances containing medetomidine can develop severe withdrawal when they stop. Symptoms may begin quickly and can include: 

• Dangerously high blood pressure or a fast heart rate 

• Anxiety or restlessness 

• Severe nausea and vomiting 

• Shaking or heavy sweating 

• Confusion or going in and out of awareness 

Severe withdrawal can damage the body's organs and may require intensive care. Call 911 or go to a hospital if severe symptoms develop. 

How can people who use substances reduce risks? 

Because medetomidine may be present in the drug supply without a person’s knowledge, it can be difficult to avoid exposure completely.  

• Never use alone. Have someone nearby who knows where the naloxone is, how to use it and when to call for help. 

• Know the signs of medetomidine withdrawal. As aforementioned, withdrawal can begin quickly, and may cause dangerously high blood pressure, a fast heart rate, nausea, vomiting, shaking, sweating, or confusion.  

• Avoid mixing substances with alcohol, anxiety medications such as Xanax or Valium, or other substances that can slow breathing. 

• Use in a safe place to reduce the risk of falling or being injured if you become very sleepy. 

• Pay attention to local public health alerts about changes in the drug supply. 

How to get help

Support is available, and recovery is possible. Because medetomidine is usually mixed with fentanyl, care may initially need to address both opioid and medetomidine withdrawal, followed by treatment for substance use disorder. Medications can help treat opioid cravings and lower the risk of overdose. 

Visit Shatterproof Treatment Atlas to find treatment services near you, filter by type and see which providers accept your insurance. If severe withdrawal symptoms are present, seek emergency medical care. 

The illegal drug supply is changing quickly. Accurate information can help people understand the risks, respond to overdoses, and seek care without judgment.