VIENNA, Austria – 4 February 2025: The UNODC Early Warning Advisory on New Psychoactive Substances has evidence of the emergence of nitazenes on a global scale. At this point in time, there are strong signals for a further spread of this group of synthetic opioids.
The first nitazene, isotonitazene, was reported to UNODC only in 2019. By now, this group is already counting 26 different substances (see Figure 1 and 2) being identified in 30 countries in Europe, North America, Oceania, South America and Southeast Asia (see Figure 3).
Figure 1: Number of different nitazenes reported to UNODC EWA over time
Source: United Nations, UNODC Early Warning Advisory on New Psychoactive Substances (EWA), Database (accessed on 21 January 2025).
Note: Data collection for 2024 and 2025 is not yet complete.
*The chemical names of controlled substances in the EWA are identical to the chemical names mentioned in the International Drug Control Conventions.
**These nitazenes were reviewed at the 47th WHO Expert Committee on Drug Dependence (ECDD) meeting in October 2024 and recommended for scheduling (to be added to the Single Convention on Narcotic Drugs of 1961 (Schedule I)). The chemical names are identical to the Annex 1: 47th WHO ECDD summary assessments and recommendations.
Figure 2: Number of different nitazenes reported to UNODC EWA in biological and drug samples by year, 2019-2024*
Source: United Nations, UNODC Early Warning Advisory on New Psychoactive Substances (EWA), Database (accessed on 21 January 2025).
Note: *Data collection for 2024 is not yet complete.
Figure 3: Number of different countries/territories reporting nitazenes to UNODC EWA by year, 2019-2024*
Source: United Nations, UNODC Early Warning Advisory on New Psychoactive Substances (EWA), Database (accessed on 21 January 2025).
Note: *Data collection for 2024 is not yet complete.
In 2023, ten synthetic opioids were reported for the first time to the UNODC EWA. Out of these, seven belonged to the group of nitazenes and three to fentanyl analogues. In 2024, so far seven synthetic opioids have been reported for the first time (data collection is not yet complete): six nitazenes (desnitroclonitazene, fluetonitazene, fluetonitazepyne, isotonitazepyne, methylenedioxynitazene and N-desethyl protonitazene) and one other synthetic opioid (N-propionitrile chlorphine).
During the time period 2019-2024*[1], 292 toxicology cases (22 per cent female, 67 per cent male and 11 percent unknown/not reported) with 13 NPS belonging to the group of nitazenes were notified to the UNODC EWA by seven reporter countries/territories[2]. 82 per cent of all nitazene toxicology cases during this time period were post-mortem cases, followed by 14 per cent clinical admission and 4 per cent drug driving cases. The top three substances most identified in nitazene toxicology cases from 2019 to 2024* were protonitazene (120 cases), metonitazene (110 cases) and isotonitazene (30 cases).
Many of the nitazenes can be even more potent than fentanyl analogues[3]. While more research is needed to better understand their potency and pharmacology, the fact that nitazenes are appearing in a large number of fatal cases is an alert signal. For example in Europe, nitazenes have already led to clusters of overdose events in some countries, such as Ireland and the United Kingdom.
Six nitazenes have been placed under international control, and four more have been recommended for international control by the WHO. In view of the rapid emergence and spread of nitazenes, the four spheres of action of the UNODC Synthetic Drug Strategy, multilateralism, counter narcotics, science-based health responses, and early warning need to be taken into account.
The rapid diversification of nitazenes can pose significant challenges to the work of law enforcement, forensic drug testing and toxicology laboratories and calls for preparedness in terms of improved capabilities, methodologies and routine screening to be able to detect nitazenes.
On the health side, preparedness for outbreaks of overdose events related to the emergence of nitazenes on illicit drug markets could be improved, by strengthening early warning systems, awareness and training of first responders and other people likely to witness an overdose, and overdose prevention and management. Opioid overdoses can be preventable through e.g. comprehensive drug dependence treatment and care programmes and, if witnessed, reversible through an adequate emergency response including the administration of naloxone, an opioid antagonist which rapidly and safely reverses the effects of opioids (for further information, please see the S-O-S initiative, developed by UNODC in collaboration with WHO).
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[1] *Data collection for 2024 is not yet complete.
[2] Although the analysis allows for a broader understanding of the associated harm of nitazenes, it is not an exhaustive representation of the variety and toxicity of nitazenes present globally.
[3] For more information, please see: United Nations Office on Drugs and Crime (UNODC), World Drug Report 2024 (United Nations publication, 2024) or Vandeputte Marthe M. and others, “Characterization of novel nitazene recreational drugs: Insights into their risk potential from in vitro µ-opioid receptor assays and in vivo behavioral studies in mice”, Pharmacological Research, vol. 210, (December 2024).
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For more information, please see:
United Nations Office on Drugs and Crime (UNODC), “June 2024 - UNODC: CND decision on international control of Butonitazene enters into force in June 2024”, news clip, 10 June 2024.
United Nations Office on Drugs and Crime (UNODC), “February 2024 - Nitazenes – a new group of synthetic opioids emerges”, news clip, 7 March 2024.
United Nations Office on Drugs and Crime (UNODC), “Current NPS Threats”, vol. 7, July 2024.
United Nations Office on Drugs and Crime (UNODC), World Drug Report 2024 (United Nations publication, 2024).
European Union Drugs Agency, “EU Drug Market: New psychoactive substances — Distribution and supply in Europe: New opioids”, 27 June 2024.