Essex Police have reported the presence of medetomidine, a veterinary sedative, in heroin seized in June 2025.
While this particular sample was not linked to an overdose death, medetomidine has previously been identified in other drug-related deaths in the county, including a case in March 2025 where it was found alongside nitazine and xylazine. Toxicologists and substance misuse partners have also reported that many affected individuals experience delusions or hallucinations after using drugs containing medetomidine.
What is medetomidine?
Medetomidine is a veterinary anaesthetic and sedative similar to xylazine. It has recently emerged as an illicit drug adulterant, particularly in mixtures containing synthetic opioids like fentanyl. These combinations, sometimes referred to as ‘tranq’, greatly increase sedative effects and overdose risk.
Research from Durham University (May 2025) found that in Philadelphia, medetomidine was present in 87% of fentanyl samples just six months after first being detected. Medetomidine is believed to enhance the euphoric effects of opioids, but it is even more potent and longer-lasting than Xylazine.
Health risks
Overdose or exposure to medetomidine can cause:
- Extreme sleepiness or unresponsiveness.
- Very low blood pressure.
- Slow heart rate.
- Breathing difficulties or respiratory failure.
- Coma or death.
Medetomidine depresses the central nervous system and slows the heart rate. When used with opioids, these effects are intensified, greatly increasing the risk of fatal overdose.
Naloxone use
Medetomidine is not an opioid, so naloxone will not reverse its effects. However, because it is often mixed with opioids, naloxone should still be administered in a suspected overdose, as it can reverse the opioid component and may still save a life.
Actions required
Share this alert with those who might use similar substances or work with those who do, and encourage them to seek help and advice. Ensure those who need to be are aware of the signs of overdose and the appropriate emergency response, including the use of naloxone where indicated. Report any unusual drug-related presentations or adverse reactions through local reporting channels. Stay alert and share this information.
Raising awareness can prevent harm and save lives.
This blog was originally published by Forward. You can read the original post here.
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