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    ☠ This is an extremely potent opioid active in microgram doses. Accidental overdose can be rapidly fatal. Naloxone should always be on hand.

    Parafluorofentanyl Encyclopedic
    Encyclopedic
    Typical encyclopedia coverage. Cross-reference for important decisions.
    • 1 source
    • 1 ROA with full dose ladder
    • duration data present
    • 29 combo interactions documented
    • classified Tentative

    Aliases: Pff, 4-fluorofentanyl

    Depressant Opioid

    Summary TripSit

    Rare, little known and extremely potent analogue of Fentanyl developed by Janssen Pharmaceutica in the 1960s. Use with extreme caution and never mix with other depressants.

    Dose Information dose.wiki TripSit

    ROA Light Common Strong Heavy
    Insufflated 10-25ug 25-40ug 40-65ug 65ug+
    Light Common Strong Heavy
    Sources

    Insufflated

    Dose ladder — dose.wiki, TripSit

    Onset, Duration & After-effects TripSit

    ROA Onset Peak After Effects
    Insufflated 0-1 min 2-3 hrs 1-2 hrs

    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

    Combinations TripSit

    Cross-Check Parafluorofentanyl with another substance

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

    💊 Pill Identifier 📖 TripSit
    Add to PsychonautWiki Journal

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

Insufflated dose (µg): light 10-25ug · common 25-40ug · strong 40-65ug · heavy 65ug+

Insufflated duration: onset 0-1m · peak 2-3h · after-effects 1-2h

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 ~ 32.5 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.