Medetomidine

Medetomidine is a veterinary sedative, similar to xylazine (tranq), that was first found in Philadelphia’s drug supply in May 2024. It is not an opioid, but is found in the dope (street opioid) supply. Although similar to xylazine, medetomidine is 100-200 times more potent and can cause longer-lasting sedation and low heart rates, as well as more severe withdrawal symptoms.

Since the introduction of medetomidine, there has been an increase and variation in withdrawal symptoms, a decrease in the number of patients seeking treatment for xylazine-associated wounds, and a decrease in the presence of xylazine in Philadelphia’s drug supply. From May 2024 to November 2024, the percentage of Philadelphia dope samples with medetomidine increased from 29% to 87%, while the percentage of samples with xylazine decreased from 97% to 42%, suggesting that medetomidine is quickly replacing xylazine in the dope supply. During this period, medetomidine was also found in overdose death data from the Philadelphia Department of Public Health’s (PDPH) Medical Examiner’s Office (MEO) and, like xylazine, always found in combination with fentanyl.

Medical and harm reduction responses to medetomidine are evolving. We will continue to update these resources and reports. (last updated 6/6/2025)

Symptoms and Overdose

The main effect of medetomidine is heavy sedation, but it can also cause low blood pressure and slow heart rate, dizziness, extreme tiredness, shortness of breath, nausea, blurred vision, and confusion.

Because of the heavy sedation, opioid overdoses that involve medetomidine may look like an individual is still sedated and non-responsive after receiving naloxone. That is because medetomidine is not an opioid, so the sedation from medetomidine will not be reversed by using naloxone. So, when you are reversing an overdose, it is important to focus on breathing rather than responsiveness. Some tips to focus on breathing include ensuring that the person takes at least one breath every five seconds and is not pale, gray, or blue. If possible, have a plan ready to monitor or transition the person.

Visit our training page to learn how to recognize and reverse an opioid overdose.

Withdrawal

The effects of medetomidine differ from xylazine. This is clearly displayed in new emergency department (ED) syndromic data, which shows a rapid increase in ED visits for substance use withdrawal and a rapid decrease in ED visits for substance use related skin and soft tissue infections following the introduction of medetomidine. Read more about these trends in our May 2025 CHART.

Medetomidine withdrawal has been described in PDPH’s December 2024 HAN and two MMRW reports from the CDC. The symptoms of medetomidine withdrawal can start rapidly and include: 

  • Fast heart rate (>100 beats per minute)  

  • Dangerously high blood pressure (>180/100) 

  • Uncontrollable nausea and vomiting 

  • Tremor  

  • Excessive sweating 

  • Changing levels of alertness 

Most patients who go to the hospital for medetomidine withdrawal need to be admitted to the intensive care unit (ICU). Treatment strategies for medetomidine withdrawal are evolving, and are described in PDPH’s December HAN, as well as the University of Pennsylvania Center for Addiction Medicine and Policy website.  

PDPH recommends a lower threshold in outpatient settings to refer patients experiencing withdrawal to a higher level of care if they are exhibiting severe symptoms.

Fast Facts

  • No. At the moment, we have only found medetomidine in combination with fentanyl, in dope samples.

  • Yes. Medetomidine test strips are now commercially available. These test strips allow individuals to test for the presence or absence of medetomidine in their substances. The Philadelphia Department of Public Health works with local community groups to distribute the tests strips. Find a community partner on the get supplies page. Medetomidine test strips work like fentanyl test strips- you just need to dip the strip in a mixture of a small amount of drug residue and water. Reading the results is the same as reading a fentanyl test strip, two lines mean that it is negative and medetomidine hasn't been detected, and one line means positive and that medetomidine was detected.

    Medetomidine test strips are a new tool. Information on the effects of the drug and recommendations for the use of these test strips can change. Continue to check this page for updated information.

    The Philadelphia Department of Public Health will continue to work with a forensic toxicology lab to test drug samples and identify emerging drugs, including medetomidine.

  • Unfortunately, medetomidine has been found in almost 90% of dope drug samples. However, if you're not sure, you can follow these steps.

    First, try to ask around and see how the drug is making other people feel before you buy or use it. Since medetomidine can cause a really heavy nod, try to use somewhere that you will be safe and won’t fall and hurt yourself. Finally, if you think there is medetomidine in your dope let others know - including someone at your local exchange program - so folks know to be careful.

  • No, other states including North Carolina, Ohio, and Illinois have identified medetomidine in their local supply. Read more about their cases in the Centers for Disease Control and Prevention (CDC)’s Morbidity and Mortality Weekly Report.

  • Not exactly. Medetomidine is not an opioid, so naloxone (NARCAN®) will not reverse a purely xylazine overdose. However, because medetomidine is always found in combination with opioids, including fentanyl, naloxone (NARCAN®) should still be administered whenever an opioid-involved overdose is suspected.

  • Research has not shown an association between medetomidine and skin wounds. Recent data from emergency department visits has shown that rates of substance use related skin and soft tissue infections (including wounds) fell to the lowest rate since Q1 2021 at the same time as the increase in medetomidine and the decrease in xylazine in the dope supply.

    If you are experiencing substance use related wounds, many organizations in the Kensington area offer wound care and supplies. View locations and hours of operation.

    Are you a medical provider looking for recommendations for treating substance use-associated wounds? Visit the resources for healthcare providers page for more information.

  • Yes. Withdrawal from medetomidine can cause racing heart, severe nausea and vomiting, excessive sweating, tremors, and confusion.

Printable Materials

Community alert informational poster about medetomidine causing severe withdrawal, including drug description, effects, sources, precautions, and emergency contacts.
Download Medetomidine Withdrawal Community Alert
Community alert from Philadelphia's Department of Public Health about the presence of medetomidine, a drug found in local drug supply. The alert explains the drug's effects, where it was found, precautions, and resources for help.
Download Medetomidine Community Alert

This page is currently under development. Information regarding medetomidine, its effects, and treatment and harm reduction recommendations are still developing. Resources for community members, non-medical organizations, and healthcare providers will be available on this page as it becomes available. If you have any questions about information or material on this page, contact DPH.Opioid@phila.gov.