Nitazenes are a group of powerful synthetic opioids that were created 50 years ago by a Swiss chemical company as potential pain relief medications. However, they were so potent, they were never approved as a medicine. These drugs are µ-opioid receptor agonists that produce psychoactive effects comparable to morphine, heroin, and oxycodone.
In the past few years, several nitazenes have re-emerged in the illicit recreational drug market. At least 23 variants of nitazines have been confirmed worldwide. Some of them (isotonitazene, metonitazine, protonitazene, and etonitazene) are up to 40 times more potent than fentanyl and 500 times more potent than heroin. They have already caused hundreds of deaths in Europe, the United Kingdom, and North America.
Nitazenes are available in powders, counterfeit prescription medicines, including fake oxycodone and benzodiazepine pills. They have most frequently been combined with fentanyl but may also be used with benzodiazepines, cocaine, heroin, methamphetamine, and tramadol.
Bellingcat has uncovered more than 1,000 online advertisements for 6 of the most common types of nitazenes. These ads offered worldwide delivery. Many of the accounts were linked to companies in China.
The lethal doses for nitazenes in humans, particularly in combination with other drugs, are not known. Many factors influence overdose-related morbidity and mortality, including not only the drug, but also the amount taken, the route of administration, possible drug-drug interactions or drug-alcohol interactions, body weight, opioid tolerance, and underlying health status.
The emergence of nitazenes creates additional concern as people with substance use disorder seek more potent drugs to satisfy their addiction. Routine illicit drug tests do not detect nitrazenes. Physicians treating treating people with drug-induced respiratory depression may not be aware of the presence of nitazenes.
In theory, some nitazenes can be antagonized by the opioid receptor antagonists, such as naloxone and nalmefene, but it is not clear if the high potency and impurities of the nitazenes might limit their effectiveness.
References
Pergolizzi J et al. Old Drugs and New Challenges: A Narrative Review of Nitazenes. Cureus, 2023 Jun; 15(6): e40736. Published online 2023 Jun 21. doi: 10.7759/cureus.40736
The Rise of Nitazines: Chines Suppliers Behind Ads for Deadly Opioids Targeting Europe, Bellingcat.com, January 20, 2025. https://www.bellingcat.com/news/2025/01/20/chinese-link-to-nitazenes-targeting-europe/
How to resolve AdBlock issue? 