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    Mephenaqualone Encyclopedic
    Encyclopedic
    Typical encyclopedia coverage. Cross-reference for important decisions.
    • 1 source
    • 1 ROA with full dose ladder
    • duration data present
    • toxicity data (PsychonautWiki)

    Depressant

    Summary PsychonautWiki

    Mephenaqualone is a central nervous system (CNS) depressant of the quinazolinone class that acts as a sedative and hypnotic. It is an analogue of methaqualone, sharing a similar chemical structure and pharmacological effects.

    Dose Information dose.wiki PsychonautWiki

    ROA Light Common Strong Heavy
    Oral 0.5-1.5mg 1.5-2.5mg 2.5-4mg 4mg+
    Light Common Strong Heavy
    Sources

    Oral

    Dose ladder — dose.wiki, PsychonautWiki

    Onset, Duration & After-effects PsychonautWiki

    ROA Onset Comeup Peak Offset After Effects Total
    Oral 30-42 min 6-12 min 2-4 hrs 10-15 hrs 6-12 hrs 12.6-19.9 hrs

    Tolerance

    Build-up develops over 1–4 weeks of regular use
    Reset Falls after you stop, at a rate that varies from person to person. If you've been using regularly, cut down gradually with medical help rather than stopping suddenly.

    No tolerance chart. Our decay curves for these drugs were estimates, and a curve can make tolerance look longer-lasting than it is, which is the dangerous direction.

    How fast tolerance to these drugs fades after a break has not been measured well enough to draw, so don't count on a dose you used to take still being safe: after time off, start with a much smaller amount and don't use alone. Mixing sedatives with each other, with alcohol or with opioids sharply raises the risk of a fatal overdose. If you've been using regularly, don't stop suddenly: withdrawal from benzodiazepines, alcohol or GHB/GBL can cause seizures or delirium, so get medical help to cut down gradually.

    Sources: FRANK: benzodiazepines · Alcohol and Drug Foundation: GHB · FDA 2020: benzodiazepine boxed warning · FDA 2019: gabapentinoids and breathing · NHS: alcohol use disorder

    Effects

    Positive
    Negative
    Neutral
    Positive
    Negative
    Positive
    Negative
    Neutral
    Mephenaqualone's nerd page Pharmacology, chemical data, effect profiles, and more
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    Helpful Links

    📖 PsychonautWiki
    Import into PsychonautWiki Journal

    The PsychonautWiki Journal app includes Mephenaqualone, but its built-in data can be thinner than ours. Importing this file adds a separate "Mephenaqualone (Substance Search)" custom substance with our dose ranges and durations, so you can log against whichever you prefer. It leaves tolerance out on purpose, for the reason given under Tolerance above.

    ⬇ Download import file Import this file as custom substances and you get "Mephenaqualone (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.

    Ranges are harm-reduction guidance, not a prescription.