Medetomidine is a very strong sedative that has been found mixed into illegal drugs. This page explains what it is, why it is a risk, and what you can do to keep yourself and other people safer.
What is medetomidine?
Medetomidine is a sedative used by vets. It belongs to the same family of drugs as xylazine but is much stronger, and its effects can last longer. It is sometimes called “rhino tranq”.
Medetomidine is not an opioid. It is most often found mixed with opioids such as heroin, fentanyl or nitazenes. In the UK it has also been found in fake tablets sold as diazepam.
Why is it a risk?
You may not know you are taking it. Medetomidine is not sold on its own. It is added to other drugs, and you cannot see, smell or taste it.
It causes very heavy sedation. Medetomidine can leave people deeply unconscious for hours. It slows the heart, lowers blood pressure and can slow breathing. Mixed with opioids, the risk of a fatal overdose is higher.
Naloxone does not reverse it. Naloxone only works on opioids. It is still vital to give it, because medetomidine is nearly always mixed with an opioid, but the person may stay sedated after their breathing returns.
Withdrawal can be a medical emergency. People who have been using drugs containing medetomidine regularly can become very unwell within hours of stopping. Symptoms include a racing heart, very high blood pressure, severe vomiting that will not stop, shaking, sweating and confusion. This needs hospital treatment.
Being unconscious for a long time carries its own risks. People can be injured by lying in one position for hours, get dangerously cold, or be robbed or assaulted.
Reducing the risk
The only way to avoid the risk completely is not to take drugs that could contain medetomidine. If you are going to use, these steps can lower the risk:
- Try not to use alone. If you are with others, take turns so someone is always able to respond.
- Start low and go slow. Take a small test dose first and wait before taking more, especially with a new batch or a new supplier.
- Carry naloxone. It will not reverse medetomidine, but it will reverse the opioids it is usually mixed with, and that can save a life.
- Use somewhere safe. Choose a place where you will be warm, out of harm’s way, and found quickly if you become unconscious.
- Do not stop suddenly on your own. If you think your drugs have contained medetomidine and you want to stop or cut down, talk to us first so it can be done safely.
- Avoid mixing. Using medetomidine or opioids with alcohol, benzodiazepines, pregabalin or gabapentin greatly increases the risk of overdose.
- Only take tablets that came from a pharmacy. Tablets bought online or from a dealer may not contain what the packaging says.
Test your drugs. Medetomidine test strips are available free from Wirral Ways. They can show if medetomidine is present, but they are not a guarantee. A strip only tests the small sample you put on it, and it will not detect fentanyl, nitazenes or xylazine (we have separate test strips for those). Even after a negative result, start low, go slow, and keep naloxone close.
Signs of an overdose
Someone may be overdosing if they:
- cannot be woken, or do not respond to your voice or touch
- are breathing very slowly, shallowly, or not at all
- are making snoring, gurgling or choking sounds
- have blue or grey lips and fingertips
- have pale, cold or clammy skin
- have a very slow pulse
What to do if someone overdoses
- Call 999 and ask for an ambulance. Say the person is unresponsive and not breathing properly.
- Give naloxone if you have it. Follow the instructions in the kit. Anyone can give naloxone in an emergency.
- If they are breathing, put them in the recovery position (on their side, with their head tilted back to keep the airway open).
- If they are not breathing, follow the instructions from the 999 call handler. They will talk you through what to do.
- Watch their breathing, not whether they wake up. If breathing has not improved after 2 to 3 minutes, give another dose of naloxone. If they are breathing normally but still unconscious, that may be the medetomidine. Keep them in the recovery position and keep checking their breathing.
- Stay with them until help arrives. Naloxone wears off, and the overdose can return.
Do not put the person in a bath, give them anything to eat or drink, or leave them to sleep it off.
Signs of medetomidine withdrawal
Call 999 if someone who uses opioids or street tablets regularly has stopped or run out and has:
- a racing or pounding heart
- severe vomiting that will not stop
- heavy shaking or sweating
- confusion or extreme restlessness
Tell the ambulance crew that medetomidine may be involved. Usual treatment for opioid withdrawal may not be enough on its own.
Get support
You do not have to be ready to stop using to talk to us. We offer free, confidential support, including harm reduction advice, drug test strips, wound care advice and support, and naloxone kits with training on how to use them.
Phone: 0151 556 1335
Email: wirral.services@cgl.org.uk
Website: www.wirralways.org.uk
If you are worried about someone else’s drug use, we can support you too.
Last Updated on 2 October 2026