"Highly potent synthetic opioids have not played such a prominent role in rising deaths among people who use drugs in the UK. Global drug markets are, however, rapidly evolving. Of particular concern is the emergence of nitazenes: a class of synthetic opioids developed by the pharmaceutical industry in the 1950s but never approved as medicines.3 Like other opioids, nitazenes can cause fatal respiratory depression, and some are hundreds of times more potent than heroin (table).3 In the UK, nitazenes have been detected in substances sold as other opioids, benzodiazepines, and cannabis products.4 This means many consumers are using nitazenes inadvertently, unaware of the risks they face."

Source

Holland A, Copeland CS, Shorter GW, et al. Nitazenes-heralding a second wave for the UK drug-related death crisis?. Lancet Public Health. 2024;9(2):e71-e72. doi:10.1016/S2468-2667(24)00001-X