The illicit drug supply continues to change, creating new risks for people who use substances and new challenges for healthcare providers. One substance receiving growing attention is medetomidine, a powerful veterinary sedative that is increasingly being detected in the illegal fentanyl supply.
In April 2026, the Centers for Disease Control and Prevention (CDC) issued a health advisory warning about increasing medetomidine detections across the United States, particularly in the Northeast. The agency also warned about a potentially severe withdrawal syndrome associated with repeated exposure.
Understanding what medetomidine is, how it affects the body, and how to respond to a suspected overdose can help individuals, families, treatment providers, and communities navigate an increasingly unpredictable drug supply.
What Is Medetomidine?
Medetomidine is a sedative and pain-relieving medication used in veterinary medicine. It belongs to a class of drugs known as alpha-2 adrenergic agonists.
Medetomidine itself is not approved for use in humans in the United States. However, one of its components, dexmedetomidine, is approved for medical use in people and may be used for sedation during certain procedures or in critical care settings.
Medetomidine can cause profound and sometimes prolonged sedation, a dangerously slow heart rate known as bradycardia, and low blood pressure.
Why Is Medetomidine Showing Up in Fentanyl?
Medetomidine has increasingly been detected alongside illegally manufactured fentanyl.
According to the CDC, medetomidine was first identified in the illegal U.S. drug supply in 2021. Reports to the National Forensic Laboratory Information System increased from 247 in 2023 to 2,616 in 2024 and then to more than 8,200 reports in 2025. More than half of the reports in 2025 came from the Northeast.
The connection with fentanyl is especially significant. Among medetomidine-positive drug samples tested through selected surveillance sites between July and December 2025, 98% also contained fentanyl.
Medetomidine may also be referred to as “rhino tranq,” “mede,” or “dex.”
Researchers initially raised concerns about veterinary medications being diverted into the drug supply. More recent testing, however, suggests that at least some medetomidine found in illegal drugs is being manufactured in clandestine laboratories rather than coming from pharmaceutical or veterinary products.
Why Is Medetomidine Dangerous?
One of the biggest concerns is that people may have no idea medetomidine is present in the drug they are using.
When medetomidine is combined with fentanyl and other substances, recognizing and responding to an overdose may become more complicated.
Profound and Prolonged Sedation
Medetomidine can cause deep sedation that may continue even after naloxone has reversed the opioid effects of fentanyl.
Other signs of medetomidine exposure can include:
- Very slow heart rate
- Low blood pressure
- Extreme drowsiness or unconsciousness
- Prolonged sedation
The CDC has documented heart rates as low as 32 beats per minute in reported cases involving medetomidine.
Does Naloxone Work on Medetomidine?
Naloxone does not reverse medetomidine itself.
However, that does not mean naloxone should be withheld during a suspected overdose.
Fentanyl is present in the overwhelming majority of medetomidine-involved overdoses. Naloxone can reverse the opioid effects of fentanyl and help restore normal breathing even though sedation caused by medetomidine may continue.
If you believe someone is experiencing an overdose:
- Call 911.
- Administer naloxone if it is available.
- Give additional doses every two to three minutes if needed to restore breathing.
- Place the person in the recovery position and keep their airway clear.
- Stay with the person until emergency medical help arrives.
The goal of naloxone is to restore breathing, not necessarily to make the person fully alert.
Medetomidine Withdrawal Can Also Be Dangerous
One of the most concerning developments surrounding medetomidine is the severity of withdrawal associated with repeated exposure.
Stopping medetomidine after regular exposure can trigger an intense withdrawal syndrome that may require emergency care or even treatment in an intensive care unit.
Symptoms can include:
- Dangerously high blood pressure
- Rapid heart rate
- Severe nausea and vomiting
- Tremors
- Chest pain
- Anxiety or agitation
- Fluctuating levels of alertness
Symptoms may begin within hours after a person’s last exposure and can peak approximately 18 to 36 hours later. Severe cases have been associated with serious complications involving the heart and brain.
In Philadelphia, 165 patients across three health systems were hospitalized between September 2024 and January 2025 for fentanyl withdrawal complicated by severe autonomic dysfunction after medetomidine became increasingly prevalent in the local drug supply.
Anyone experiencing severe vomiting, chest pain, extreme changes in blood pressure or heart rate, or changes in consciousness after stopping fentanyl or other illicit opioids should seek emergency medical attention.
Can Medetomidine Be Detected With Test Strips?
Drug checking can provide additional information about what may be present in a substance.
The CDC reports that test strips are now available for several substances, including fentanyl, xylazine, and medetomidine. However, drug test strips are not perfect and can produce false-negative results.
A negative test should never be considered a guarantee that a drug does not contain medetomidine, fentanyl, or another unexpected substance.
Is Medetomidine the Same as Xylazine?
No. Medetomidine and xylazine are different drugs, although both are veterinary medications with sedating effects and both have appeared in the illicit opioid supply.
Medetomidine is another alpha-2 adrenergic agonist, but the CDC describes it as more potent and longer-acting than xylazine. Unlike xylazine, medetomidine has not currently been strongly associated with the severe wounds that have become a major concern with xylazine exposure.
Both substances demonstrate how quickly the illicit drug supply can change.
An Increasingly Unpredictable Drug Supply
Medetomidine is not simply another name appearing on a growing list of drug contaminants. Its increasing presence in fentanyl, prolonged sedating effects, limited response to naloxone, and potential for severe withdrawal create additional challenges for people who use drugs, their families, first responders, and healthcare providers.
Awareness is especially important because people may be exposed to medetomidine without knowing it.
If you or someone you love is struggling with opioid or substance use, treatment is available. Evidence-based addiction treatment can help address substance use, withdrawal, mental health needs, and the other challenges that often accompany addiction.
Help Is Available
The drug supply is changing quickly, but treatment and support are available. If you or someone you love is struggling with fentanyl, opioids, or other substance use, Naaman Network can help.
Our team provides compassionate, evidence-based addiction treatment designed to meet individuals where they are and support lasting recovery.
Contact Naaman Network today to learn more about treatment options and take the next step toward recovery.
