Nitazenes are a class of lab-made (synthetic) opioids that may be as powerful or more powerful than fentanyl.4 They were developed in research labs in the 1950s as potential pain relievers but never marketed. Nitazenes are most often sold as a white powder or tablets. People may not be aware that they have taken nitazenes, as they may be added to other substances, including fentanyl, heroin, and benzodiazepines.5
Nitazenes began to re-emerge in the drug supply in 2019, after the U.S. Drug Enforcement Administration banned fentanyl-related substances.6,7 Researchers and authorities are monitoring nitazenes, including isotonitazene, protonitazene, etonitazene, N-piperidinyl etonitazene, and metonitazene. Many nitazenes are listed as Schedule 1 drugs under the Controlled Substances Act.
Like all opioids, nitazenes can slow breathing, blood pressure, and heart rate to dangerously low levels, potentially contributing to overdose. Preliminary NIDA-supported research shows that the opioid overdose reversal medication naloxone is effective with isonitazene, metonitazene, and N-piperidinyl etonitazene, though it may require repeated doses.8 More research is needed to confirm these findings with additional nitazenes and in larger groups of people. Fentanyl test strips do not detect nitazenes.