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    Disclaimer
    ☠ This substance has been associated with serious adverse events including fatalities. Use extreme caution.
    ☢ This substance has an extremely narrow safety margin. Small dosing errors can lead to life-threatening effects.
    ☠ Nitazene-class opioids are extremely potent, often exceeding fentanyl in strength. Even trace amounts can be fatal. Fentanyl test strips do NOT detect nitazenes — a negative strip does not rule one out. Naloxone works, but often needs repeated doses, and re-sedation can follow once it wears off: call emergency services and stay with the person.
    🧪 This is a research chemical with limited data on its long-term health effects, toxicity profile, and safe dosage ranges.
    ⚠ Opioids carry significant risk of respiratory depression, physical dependence, and fatal overdose. Never combine with other depressants.

    Isotonitazepyne Encyclopedic
    Encyclopedic
    Typical encyclopedia coverage. Cross-reference for important decisions.
    • 2 corroborating sources
    • 2 ROAs with full dose ladders
    • duration data present
    • 29 combo interactions documented
    • classified Research-chemical
    • dose data not in PW/TripSit (unverifiable)

    Aliases: Npi, Iso-pyne

    Depressant Research-chemical Opioid

    Summary dose.wiki

    Isotonitazepyne (also known as Iso-pyne) is a synthetic opioid of the benzimidazole class, encountered as a research chemical and acting as a central nervous system depressant. It is approximately 1000 times more potent than morphine in vitro, with active doses in the microgram range, making volumetric dosing or pre-measured nasal spray formulations essential. Counterfeit pharmaceutical pills marketed as oxycodone and containing 3-4 mg per pill have caused multiple fatalities in Europe.

    Dose Information Drugs.Wiki

    Dose basis. The dose figures on this page are not clinical data. They are aggregated from community reports by a secondary source whose own notes state there is no human pharmacokinetic study behind them, and our internal audit flags this substance's dosing as unverifiable. Treat them as a rough orientation, not a safe range. This is a microgram-active opioid: a normal milligram scale cannot weigh a dose of it accurately, and a weighing error here is measured in lethal multiples rather than percentages. Volumetric dosing is the only defensible method, and batch-to-batch potency in the unregulated supply varies enormously. Assume full respiratory depression, keep naloxone to hand, never dose alone, and never combine with benzodiazepines, alcohol or other depressants.

    ROA Light Common Strong Heavy
    Insufflated 25-100µg 100-300µg 300-600µg 600µg+
    Oral 50-150µg 150-400µg 400-800µg 800µg+
    Light Common Strong Heavy
    Sources

    Insufflated

    Dose ladder — Drugs.Wiki

    Oral

    Dose ladder — Drugs.Wiki
    ☠ 3–4 mg per pill oral Counterfeit pills: multiple fatalities

    “Counterfeit pharmaceutical pills marketed as oxycodone and containing 3-4 mg per pill have caused multiple fatalities in Europe.” — encyclopedia summary

    Onset, Duration & After-effects dose.wiki Drugs.Wiki

    ROA Onset Comeup Peak Offset After Effects Total
    Insufflated 5-15 min 5-10 min 30-90 min 1-2 hrs 1-3 hrs 1.66-3.92 hrs
    Oral 15-30 min 10-20 min 30-90 min 1-2 hrs 1-3 hrs 1.92-4.33 hrs

    Effect Profile

    Scores (0–10) curated from multiple sources:

    • Effect keyword matching from PsychonautWiki catalog
    • Weighted by importance: core (×3), major (×2), minor (×1)

    Full methodology

    Opioid 7.3
    Strong+ 7/10

    Strong euphoria and pain relief with strong itching/nausea, mild sedation

    Euphoria / Warmth ×3
    10
    physical euphoria cognitive euphoria euphoria warmth
    Analgesia ×2
    8
    pain relief analgesia
    Sedation / Relaxation ×1
    5
    sedation muscle relaxation
    ⚠ Itching / Nausea ×1
    10
    itching nausea constipation
    View methodology →

    Tolerance

    Build-up develops within days of regular use; analgesic tolerance faster than respiratory depression tolerance
    Reset Falls quickly once you stop, at a rate you can't judge. After any break, treat your tolerance as gone.

    No 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

    Other benzimidazole opioids (nitazenes)
    Fentanyl analogues

    Effects dose.wiki

    Positive
    Negative
    Neutral
    Positive
    Negative
    Positive
    Negative
    Neutral

    Combinations

    Cross-Check Isotonitazepyne with another substance

    Isotonitazepyne's nerd page Pharmacology, chemical data, effect profiles, and more
    →

    Helpful Links

    📖 dose.wiki
    Add to PsychonautWiki Journal

    The PsychonautWiki Journal logging app doesn't include every substance. To track Isotonitazepyne there, start adding an ingestion, search for the name, and choose to add it as a custom substance. Paste these values:

    ⬇ Download import file Import this file as custom substances and you get "Isotonitazepyne (Substance Search)" with every route's full dose ladder and timeline, no typing. Works on iOS and Android (v15+); the format is confirmed by the app's developer. The manual values below work for older versions.
    Name
    Isotonitazepyne
    Unit
    µg
    Description 
    Isotonitazepyne
Source: SubstanceSearch (substancesearch.com)

Insufflated dose (µg): threshold 25 · light 25-100 · common 100-300 · strong 300-600 · heavy 600+
Oral dose (µg): threshold 50 · light 50-150 · common 150-400 · strong 400-800 · heavy 800+

Insufflated duration: onset 5-15m · come-up 5-10m · peak 0.5-1.5h · offset 1-2h · total 1.66-3.92h · after-effects 1-3h
Oral duration: onset 15-30m · come-up 10-20m · peak 0.5-1.5h · offset 1-2h · total 1.92-4.33h · after-effects 1-3h

Note: ranges are harm-reduction guidance, not a prescription. Start low, go slow, and test your substances.

    Tip: for quicker logging you can also add a Custom Unit in the app, e.g. common dose ~ 200 µg (Insufflated).

    The app keeps custom substances simple, so the full dose ranges live in the description text above. Ranges are harm-reduction guidance, not a prescription.