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    Disclaimer
    ☠ 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.

    Metonitazene Encyclopedic
    Encyclopedic
    Typical encyclopedia coverage. Cross-reference for important decisions.
    • 3 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: Metonitazine

    Depressant Research-chemical Opioid

    Summary dose.wiki

    Metonitazene is a high-potency synthetic benzimidazole opioid at least as potent as fentanyl; CFSRE places it up to 500 times the potency of morphine. It has been found unexpectedly in counterfeit oxycodone pills, heroin, and other substances. Overdoses may require higher-than-normal doses of naloxone and multiple administrations to reverse.

    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
    Oral 0.1-0.2mg 0.2-0.5mg 0.5-1mg 1mg+
    Insufflated 0.05-0.1mg 0.1-0.3mg 0.3-0.6mg 0.6mg+
    Light Common Strong Heavy
    Sources

    Oral

    Dose ladder — Drugs.Wiki

    Insufflated

    Dose ladder — Drugs.Wiki

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

    ROA Onset Peak Offset Total
    Oral 5-15 min 30-90 min 2-4 hrs 2.58-5.75 hrs
    Insufflated 1-5 min 30-90 min 2-4 hrs 2.52-5.58 hrs

    Effect Profile

    2 reports

    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 7.6
    Intense 8/10

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

    Euphoria / Warmth ×3
    10
    physical euphoria cognitive euphoria euphoria warmth
    Analgesia ×2
    8
    analgesia pain relief
    Sedation / Relaxation ×1
    7
    sedation drowsiness muscle relaxation
    ⚠ Itching / Nausea ×1
    10
    itching nausea constipation
    Based on reports from:
    Erowid Experience Reports
    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 opioids (e.g., fentanyl, morphine, heroin)

    Effects dose.wiki

    Positive
    Negative
    Neutral
    Positive
    Negative
    Positive
    Negative
    Neutral

    Combinations

    Cross-Check Metonitazene with another substance

    Community Trip Reports

    Anecdotal first-person accounts from Reddit, Erowid, Bluelight, and Dose.wiki. Click a source to expand. Reports are harm-reduction context, not medical guidance. Tags summarise each author's own verdict — how reports are classified.

    Erowid 2 reports 2 neutral visit
    A Serious Product, but Nothing Unexpected neutral exp #115491

    Experiences with narcotics had been so far limited to relatively "manageable" products namely medical morphine and what is considered a "soft" RC, bucinnazine-237. I felt there were still some things left to experience in order to call it quits with narcotics.

    Johnson · 1 - 10 mg vaporized
    Opium 2.0 in a Sense neutral exp #115329

    So I found this product on the interwebz, from a website that contributes to scientific research. They make a blend of base product with glycerine so that it could be used in vaping machines. Opium 2.0 in a sense. Looks badass but it's really just a narcotic which is "prepared" .

    Jackson · repeated vaporized
    Metonitazene's nerd page Pharmacology, chemical data, effect profiles, and more
    →

    Helpful Links

    📘 Experience Reports 📖 dose.wiki
    Add to PsychonautWiki Journal

    The PsychonautWiki Journal logging app doesn't include every substance. To track Metonitazene 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 "Metonitazene (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
    Metonitazene
    Unit
    mg
    Description 
    Metonitazene
Source: SubstanceSearch (substancesearch.com)

Oral dose (mg): threshold 0.1 · light 0.1-0.2 · common 0.2-0.5 · strong 0.5-1 · heavy 1+
Insufflated dose (mg): threshold 0.05 · light 0.05-0.1 · common 0.1-0.3 · strong 0.3-0.6 · heavy 0.6+

Oral duration: onset 5-15m · peak 0.5-1.5h · offset 2-4h · total 2.58-5.75h
Insufflated duration: onset 1-5m · peak 0.5-1.5h · offset 2-4h · total 2.52-5.58h

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 ~ 0.35 mg (Oral).

    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.