Nitazenes are a group of very strong synthetic opioids. This page explains what they are, why they carry a high risk of overdose, and what you can do to keep yourself and other people safer.
What are nitazenes?
Nitazenes are opioids made in a laboratory. They were first developed in the 1950s as painkillers but were never approved as medicines, so they have no medical use.
There are many different nitazenes and their strength varies. Some are similar in strength to fentanyl. Others are far stronger, and can be hundreds of times stronger than heroin.
Nitazenes are Class A drugs. They have been found in drugs sold across the UK and have been linked to deaths.
Why are they a risk?
You may not know you are taking them. Nitazenes are rarely sold as nitazenes. They are mixed into heroin, or pressed into fake tablets sold as oxycodone, diazepam, alprazolam (Xanax) or other medicines. You cannot see, smell or taste them.
They affect people who do not use opioids. Because nitazenes turn up in fake benzodiazepines and other tablets, people with no opioid tolerance can take them without knowing. The risk of overdose is very high.
They are not mixed evenly. One part of a batch, or one tablet in a strip, can contain far more than another.
They work fast. Nitazenes can slow or stop breathing within minutes, which leaves less time to get help.
Tolerance does not fully protect you. Even people who use opioids every day can overdose on a very small amount.
Reducing the risk
The only way to avoid the risk completely is not to take drugs that could contain nitazenes. 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. Naloxone is a medicine that temporarily reverses an opioid overdose, and it works on nitazenes. Make sure the people around you know where it is and how to use it.
- Avoid mixing. Using opioids with alcohol, benzodiazepines, pregabalin or gabapentin greatly increases the risk of overdose.
- Take extra care after a break. Your tolerance drops quickly after time in hospital, prison, detox or any period of not using.
- Only take tablets that came from a pharmacy. Tablets bought online or from a dealer may not contain what the packaging says. Carry naloxone even if you do not think you are taking an opioid.
Test your drugs. Nitazene test strips are available free from Wirral Ways. They can show if nitazenes are present, but they are not a guarantee. A strip only tests the small sample you put on it, and it does not detect every type of nitazene. Fentanyl test strips will not pick up nitazenes, so use the right strip for each. 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 very small (pinpoint) pupils
- have pale, cold or clammy skin
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.
- Give another dose of naloxone if there is no response after 2 to 3 minutes. Nitazenes are very strong, so several doses may be needed.
- Stay with them until help arrives. Naloxone wears off, and the overdose can return, sometimes more than once.
Do not put the person in a bath, give them anything to eat or drink, or leave them to sleep it off.
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, fentanyl and nitazene test strips, 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