Dr Adam Holland is a Public Health Consultant and Co-Chair of the Faculty of Public Health Drugs Special Interest Group. Dr Caroline Copeland is a Senior Lecturer in Pharmacology & Toxicology at King's College London and Director of the National Programme on Substance Abuse Deaths.

What are nitazenes and why do we need to worry about them?

Nitazenes are synthetic opioids - laboratory-produced drugs which act on the same receptors in the brain as morphine and heroin. In the UK, nitazenes have been detected in substances sold as other opioids, like heroin and oxycodone; benzodiazepines, like diazepam; and cannabis products. Some nitazenes are thousands of times stronger than heroin, so people who use them inadvertently – even in small amounts – are at high risk of overdose.

In the last couple of years we’ve seen an increasing number of deaths related to nitazenes, as well as harms related to other synthetic drugs, like the veterinary anaesthetic xylazine, synthetic cannabis, and novel benzodiazepines...