The expansion of isotonitazeno, a synthetic opioid known as ISO, has triggered international alerts due to its high potency and the risk of it being sold mixed with other drugs or in counterfeit pills. According to a report published August 18, the United Nations Office on Drugs and Crime (UNODC) Early Warning System warned in early August about the growing presence of this substance, which belongs to the nitazene family and can be five to nine times more potent than fentanyl.
Isotonitazeno was originally developed as a medication during the 1950s but was later discontinued. It reappeared on the illegal market in early 2020 and can currently be produced clandestinely through synthetic processes. The substance can appear as powder for inhalation or injection, in tablets, or in liquid forms intended for vaporization.
Dr. Iván Meléndez, a health official for Hidalgo County, Texas, stated that the high potency of the substance can cause respiratory depression, which can lead to a person stopping breathing. Former DEA agent Leo Silva noted that a primary risk involves consumers being unaware of the actual contents of pills purchased on the illegal market.
Data from February 2026 shows that nitazenes comprise a family of high-potency synthetic opioids including various analogs. Since isotonitazeno was first reported to the UNODC in 2019, the organization has received reports of 34 nitazene analogs found in seized drugs and toxicological analyses in at least 37 countries.
The DEA previously warned about nitazenes in 2022 after detecting isotonitazeno in the Washington metropolitan area. The agency reported that the substance could be mixed with fentanyl or heroin and sold as other drugs, including counterfeit tablets imitating Dilaudid and oxycodone. Identification requires laboratory analysis, making it difficult for consumers to know they are consuming a different opioid.
In the United States, approximately one thousand people have died from this drug. Its presence has been detected in more than 13 states, with higher consumption reported in Chicago. While reports of nitazenes remain lower than those for fentanyl, authorities maintain vigilance due to the substance's potency and its potential for being mixed with other substances.
Narcan, a medication used to reverse fentanyl overdoses, can also act against isotonitazeno, though information suggests that higher doses may be required. The UNODC continues to monitor the evolution and diversification of the synthetic opioid market as new analogs emerge.
