Fentanyls continue to account for the largest share of harm from the non-medical use of NPS synthetic opioids, in particular in North America, but the arrival on the market of nitazenes and orphines , which are often more potent than fentanyls, has led to a number of acute emergencies and fatal outcomes, raising public health concerns across a growing number of countries
In recent years, new synthetic opioids – nitazene analogues (2019), brorphine (2019) and other orphine analogues (2024) – that may be more potent than fentanyls have emerged in different countries.
Nitazenes appear to be more geographically widespread than fentanyls. Since the first report identifying the presence of isotonitazene, in 2019, at least 34 nitazenes have been identified across 37 countries. In 2024 alone, 29 countries reported to UNODC the presence of nitazenes on their market, compared with 18 countries that reported the presence of fentanyl analogues
Synthetic opioids have been sold in various forms, such as tablets, crystals, powder and vape refills, sprayed on plant material or even on blotter paper, or sold as falsified pharmaceutical opioids, benzodiazepines and even as opioids and stimulants.
In addition to the inherent harms associated with these substances, the risk associated with synthetic opioids also stems from the unpredictable nature of the drug supply, including variability in concentration, dilution and adulteration with other substances (e.g., xylazine and/or medetomidine).
