A potent class of synthetic opioids known as nitazenes is rapidly emerging worldwide, raising serious concern among researchers. Originally developed in the 1950s as painkillers but never approved due to their extreme risk, nitazenes are now appearing on the dark web as fentanyl listings decline.
Key facts:
Up to 500 times stronger than morphine; even trace amounts can be lethal.
In the United Kingdom, 179 deaths were recorded in the year to May 2024; thousands are suspected in the United States since 2019.
28 countries have reported seizures of at least 20 nitazene variants.
Many overdoses occur unintentionally, as nitazenes are often sold as heroin, MDMA, or oxycodone.
Naloxone remains effective for reversing overdoses, but awareness is limited.
Researchers link the rise to China’s 2019 ban on fentanyl and to the anonymity of cryptocurrency-based drug markets, which have facilitated global distribution.
Source: Nature (October 2025). DOI: 10.1038/d41586-025-03280-5