In brief
- A team from Ghent University (Belgium) has characterized “cyanazenes,” a previously unknown family of synthetic opioids, in the laboratory.
- They are chemical cousins of nitazenes: they replace a nitro group with a cyano group, a tweak that bypasses the legal definition China used in 2025 to ban that family of substances.
- The first to appear in a real-world sample, detected by drug checking services in Lisbon and Madrid, still activates the opioid receptor with enough potency to warrant concern, though current test strips for nitazenes already detect it.
A study published on August 18, 2026, in the journal Drug Testing and Analysis describes for the first time the behavior of cyanazenes, a new generation of synthetic opioids that have begun circulating as a substitute for nitazenes. The work, authored by Inez Lambrecht, Christophe Stove, and Marthe Vandeputte of the Ghent University Toxicology Laboratory, confirms that these molecules continue to strongly activate the mu-opioid receptor, the same one that triggers sedation and respiratory depression in an overdose.
A Ban, A New Molecule
Nitazenes are a family of synthetic opioids designed in the 1950s and never approved for medical use. Since 2019, they have been infiltrating the illegal opioid market, sometimes mixed with heroin or presented in counterfeit pills. In July 2025, China abruptly banned the entire chemical structure defining nitazenes, a decision that historically has a predictable side effect: as soon as one molecular door is closed, some clandestine laboratory finds a window. Cyanazenes are exactly that—a window: they substitute the nitro group that legally defines nitazenes with a cyano group, a minimal change in the formula that is sufficient to fall outside the scope of the ban without losing much of the effect on the body.
What the New Study Shows
The Belgian team tested four cyanazenes in a cellular assay that measures mu-opioid receptor activation. The most studied, 5-cyano isotodesnitazene, activates that receptor with an average potency (half-maximal effective concentration, or EC50, of 71.5 nanomolar) clearly lower than its nitro-containing cousin, isotonitazene (2.55 nanomolar, about 28 times more potent), but similar to its other relative without any group in that position, isotodesnitazene (49.2 nanomolar). Compared to fentanyl, the standard reference in these studies (15.1 nanomolar), cyanazene is several times less potent at activating the receptor, although it remains a full agonist, capable of activating it to the maximum or even beyond what fentanyl itself achieves. The substance is not just a laboratory experiment: the authors cite the discovery by a Portuguese and Spanish team that, in January 2026, identified 5-cyano isotodesnitazene in a real sample of white powder analyzed by the drug checking services Kosmicare (Lisbon) and Kykeon Analytics (Madrid), in collaboration with universities in Portugal and Australia. Fully characterizing that sample, without having any prior reference standard for the compound, took them less than two weeks.
What It Implies
The researchers themselves insist that these are in vitro data, obtained in laboratory cells and not in people, and that the actual potency in the body also depends on how each substance is metabolized. But there is news of direct interest to those who use drugs or work in harm reduction: the study confirms that the nitazene test strips already used in the field, specifically the BTNX 2.0 version, also detect cyanazenes. In other words, rapid surveillance has not been blinded to this new family, although the pattern repeats: every time a specific chemical structure is banned, a variant appears that bypasses it, and drug checking remains, once again, the first real line of defense against the unknown.
Source
- Lambrecht, I. M., Stove, C. P., Vandeputte, M. M. “In Vitro Pharmacological Characterization of a Series of 5-Cyano Desnitazene Opioids or ‘Cyanazenes'”. Drug Testing and Analysis, August 18, 2026.
Educational content written from a harm reduction perspective and with respect for individual freedom. It is not a substitute for advice from a healthcare professional and is not intended to encourage or condemn any drug use.
