Isotonitazene Stats & Data
CCN(CC)CCn1c(Cc2ccc(OC(C)C)cc2)nc2cc(ccc12)N(=O)=OOIOQREYBGDAYGT-UHFFFAOYSA-NMeasured Affinities
Guide to PHARMACOLOGYMeasured binding and functional data for isotonitazene, curated by the IUPHAR/BPS Guide to PHARMACOLOGY. Each row cites the paper it came from. Lower concentrations mean tighter binding — a value in the sub-nanomolar range indicates a very potent interaction.
| Target | Action | Measure | Value | Concentration | Species | Source |
|---|---|---|---|---|---|---|
| μ receptor OPRM1 | Full agonist | pEC50 | 10.3 | 0.05 nM | Human | PMID 37276825 |
| μ receptor Oprm1 | Full agonist | pKi | 7.95 | 11.22 nM | Rat | PMID 37276825 |
Reading this. pKi, pEC50 and pIC50 are negative log molar values, so a higher number means a tighter interaction; the concentration column converts them for you. Values from non-human species are laboratory measurements and do not translate directly to human effect. Receptor affinity is not a dose — it describes what a molecule binds, not how much of it is safe to take.
Receptor data from the IUPHAR/BPS Guide to PHARMACOLOGY (v2026.2), licensed CC BY-SA 4.0. Matched to this substance by InChIKey.
Effect Profile
CuratedStrong euphoria and pain relief with strong itching/nausea, low sedation
Tolerance & Pharmacokinetics
drugs.wikiNo tolerance chart. Our decay curves for opioids were estimates, and a curve can make tolerance look longer-lasting than it is, which is the dangerous direction.
Opioid tolerance drops fast when you stop, and even a few days off can be enough, so a dose that used to be normal can now stop your breathing. Overdose deaths rise sharply after prison, detox or leaving treatment, and tolerance also falls during a hospital stay. After any break, start with a much smaller amount, try a test dose first, don't use alone, and keep naloxone within reach. Alcohol, benzodiazepines, gabapentinoids and other sedatives make an opioid overdose much more likely.
Sources: FRANK: heroin · National Harm Reduction Coalition · WHO: opioid overdose · Merrall et al. 2010 · Binswanger et al. 2007 · Strang et al. 2003 · FDA 2019: gabapentinoids and breathing
Cross-Tolerances
Harm Reduction
drugs.wikiIsotonitazene (CAS 14188-81-9) was first characterised in illicit markets in 2019 and scheduled by the U.S. DEA in 2020. In vitro and in vivo work shows μ-opioid receptor ‘super-agonism’ and prolonged respiratory depression for its active metabolite N-desethyl isotonitazene versus fentanyl; renarcotisation after naloxone is a concern, so monitor 8–12+ hours and be prepared for repeat antagonist dosing. Drug checking and European monitoring document frequent nitazene involvement in poisonings and counterfeit ‘oxycodone/hydromorphone’ tablets; negative fentanyl test strips do not rule out nitazenes. Where available, use full-spectrum drug checking (e.g., mass spectrometry); FTIR alone may miss <5% constituents and current nitazene-specific strips may not detect all analogues. Microgram potency demands volumetric dosing; avoid weighing tiny amounts directly. For oral/sublingual use, dilute to a low concentration to enable accurate measurement; never inject alcohol/PG-based solutions. Avoid combining with any sedatives. After any abstinence of ≥48 h, markedly reduce dose due to rapid loss of tolerance. Grapefruit and other CYP3A4/CYP2D6 inhibitors can increase effects and overdose risk. If injecting occurs, the safest option is to avoid injection; if not avoided, use sterile water, new equipment, and test a very small ‘allergy dose’ with supervision; never share supplies.
References
Cited references
- EMCDDA technical report on isotonitazene (2020)
- EMCDDA risk assessment on isotonitazene (2020)
- European Drug Report 2025 – nitazenes in deaths/counterfeit meds
- European Drug Report 2024/2025 – detection challenges, higher naloxone needs (anecdotal)
- Isotonitazene PK/PD in rats (Walton et al., 2023)
- MOR super-agonism; prolonged respiratory depression for N-desethyl isotonitazene (iScience 2023)
- iScience full text (open access)
- Metabolic characterization of nitazenes – CYP involvement (2024)
- Toronto Drug Checking – nitazenes found in samples expected to be oxycodone/hydromorphone (2024)
- Saferparty.ch – nitazenes sold as ‘oxycodone’ (2024–2025 warnings)
- Saferparty.ch – nitazene ‘OC80’ counterfeit example (2025)
- Fentanyl test strips: scope/limits (TDCS resource, 2023)
- Nitazene test strips may miss analogues (TDCS brief, 2024)
- DrugWise overview on nitazenes (updated 2025)
- Naloxone clinical guidance (StatPearls, updated)
- Saferparty.ch – general opioid safer-use, injection hygiene, grapefruit caution
- Volumetric dosing harm-reduction basics (Drug Users Bible)