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    ⚠ Opioids carry significant risk of respiratory depression, physical dependence, and fatal overdose. Never combine with other depressants.

    Isomethadone Encyclopedic
    Encyclopedic
    Typical encyclopedia coverage. Cross-reference for important decisions.
    • 2 corroborating sources
    • 1 ROA with full dose ladder
    • duration data present
    • 19 combo interactions documented
    • classified Tentative

    Depressant Opioid

    Summary TripSit

    Once a pharmaceutical drug also known as isoamidone, this opioid analgesic and methadone analogue was withdrawn from the market and is seldom seen today. Rarely abused, though reports state it is around twice as potent as methadone, and more euphoric.

    Dose Information TripSit

    ROA Light Common Strong Heavy
    Oral 1.5-2.5mg 2.5-7.5mg 7.5-15mg 15mg+
    Light Common Strong Heavy

    Onset, Duration & After-effects TripSit

    ROA Onset Peak After Effects Total
    Oral 30-90 min 30-40 hrs 1-24 hrs 30-40 hrs

    Effect Profile

    Scores (1–10) curated from multiple sources:

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

    Full methodology

    Opioid 5.4
    Moderate+ 5/10

    Moderate euphoria with mild pain relief and itching/nausea, low sedation

    Euphoria / Warmth ×3
    7
    euphoria cognitive euphoria mood lift
    Analgesia ×2
    4
    analgesia
    Sedation / Relaxation ×1
    3
    sedation
    ⚠ Itching / Nausea ×1
    4
    constipation dry mouth
    View methodology →

    Add to PsychonautWiki Journal

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

Oral dose (mg): light 1.5-2.5 · common 2.5-7.5 · strong 7.5-15 · heavy 15+

Oral duration: onset 0.5-1.5h · peak 30-40h · total 30-40h · after-effects 1-24h

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 ~ 5 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.

    Tolerance

    Build-up develops within days of regular use; analgesic tolerance faster than respiratory depression tolerance
    Reset 7–14 days for partial reset; full reset may take weeks — tolerance loss greatly increases overdose risk

    Tolerance Decay

    Full tolerance 1d Half tolerance 21d Baseline ~35d

    Effects TripSit

    Positive
    • Analgesia
    • Stimulation
    Negative
    • Dry Mouth
    • Increased heart rate
    • Insomnia
    Neutral
    • Itchiness
    • Relaxant
    • Pupil constriction
    • Sedation
    Positive
    • Euphoria
    • Mood lift
    • Reduced anxiety
    • Cognitive euphoria
    • Wakefulness
    Negative
    • Constipation
    • Anxiety
    • Confusion
    • Compulsive redosing
    Neutral
    • Time distortion
    Positive
    • Increased music appreciation
    • Color enhancement
    • Tactile enhancement
    • Brightened colour
    Negative
    • Light sensitivity
    • Disinhibition
    • Appetite suppression
    • Dehydration
    Neutral
    • Dulled perception
    • Drifting

    Combinations TripSit

    Cross-Check Isomethadone with another substance

    Isomethadone's nerd page Pharmacology, chemical data, effect profiles, and more
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    Helpful Links

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