In brief
- Ghent University has measured the potency of “cyanazenes,” the newest branch of nitazenes, in the laboratory.
- The primary compound, 5-cyano isotodesnitazene, activated the mu-opioid receptor much less readily than isotonitazene and also less than fentanyl.
- The four variants analyzed proved detectable with BTNX 2.0 nitazene test strips.
A laboratory at Ghent University has quantified 5-cyano isotodesnitazene, the first nitazene to appear with a chemical modification never before described in this group of synthetic opioids. The work was published on August 18 in the journal Drug Testing and Analysis. Two conclusions stand out: the molecule is significantly less potent than its better-known relatives, and the test strips already used by drug checking services can detect it.
From nitazenes to cyanazenes
Nitazenes are synthetic opioids of the 2-benzylbenzimidazole family. They were synthesized in the 1950s and were never approved for medical use. Since 2019, they have had a growing presence in illicit markets, with a very wide range of potencies: several exceed fentanyl. The rapid emergence of new analogs is precisely what complicates the work of forensic laboratories and public health systems.
5-cyano isotodesnitazene, also called isotocyanazene, is one of those versions: the nitro group on the usual skeleton has been replaced by a cyano group. Its trail began at a drug checking service. In January, an international collaboration between two of these services and three academic institutions published the first confirmed identification of the compound in a street-purchased sample in Scientific Reports, using gas chromatography, mass spectrometry, and nuclear magnetic resonance.
What the Belgian laboratory measured
The team formed by Inez M. Lambrecht, Christophe P. Stove, and Marthe M. Vandeputte used a beta-arrestin 2 recruitment cell assay, which serves to compare how easily each molecule activates the mu-opioid receptor. The EC50 values published in the study were 71.5 for 5-cyano isotodesnitazene, 2.55 for isotonitazene, 15.1 for fentanyl, and 49.2 for isotodesnitazene. The EC50 is the concentration required to reach half of the maximum effect of each molecule: the lower the number, the more potent the substance. It took a concentration about 28 times higher of cyanazene than of isotonitazene, and almost five times higher than of fentanyl, to reach that point. The maximum efficacy of the new compound remained at 117% of that of fentanyl.
The authors repeated the experiment with three other cyanazenes, and the pattern held. Their reading is that the cyano group does not compensate for the potency lost by removing the nitro group. They also confirmed receptor activation with an authentic sample of the compound, not just a laboratory standard. And they added the most practical data of all: all cyanazenes analyzed, along with isotodesnitazene, were detectable with the BTNX 2.0 nitazene test strips.
What it implies
It is important to contextualize the scope. This is an in vitro study, performed on cell plates, which compares molecules to each other but does not translate to doses or predict what happens in a person. Less potent does not mean harmless: it remains a mu-opioid receptor agonist with efficacy higher than that of fentanyl in that assay.
The interesting part is something else. The illicit market generates variants faster than controlled substance lists are updated, as was already seen with designer benzodiazepines sold as anxiolytics in Europe, and each new branch raises the question of whether existing detection tools still work. Here, the answer was yes, and with a tool that is already in the field. None of this belongs to the realm of psychedelics, but it does to that of anyone approaching a market without reliable labels: the logic of harm reduction involves knowing what is in front of you before deciding.
Source
- Lambrecht IM, Stove CP, Vandeputte MM. In Vitro Pharmacological Characterization of a Series of 5-Cyano Desnitazene Opioids or “Cyanazenes”. Drug Testing and Analysis, August 18, 2026.
- Barra BFC et al. Collaborative harm reduction efforts lead to the first detection of 5-cyano isotodesnitazene in illicit street drugs. Scientific Reports, January 13, 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.
