Fosazepam
Encyclopedic
Encyclopedic
Typical encyclopedia coverage. Cross-reference for important decisions.
- 2 corroborating sources
- 1 ROA with full dose ladder
- duration data present
- 27 combo interactions documented
- dose data not in PW/TripSit (unverifiable)
- 2 corroborating sources
- 1 ROA with full dose ladder
- duration data present
- 27 combo interactions documented
- dose data not in PW/TripSit (unverifiable)
Summary
Fosazepam is a water-soluble phosphate ester derivative of diazepam with approximately 10-fold lower potency (100 mg fosazepam equals 10 mg diazepam). It is a prodrug that is metabolized to desmethyldiazepam (nordiazepam), which has a very long elimination half-life of approximately 72 hours. This long-acting metabolite can cause extended sedation and accumulation with repeated dosing.
Dose Information
Dose basis. Dose ranges are not well-established in formal literature; figures below are compiled primarily from user reports and cross-benzodiazepine equivalence heuristics. Start at the low end if untested, measure with a 0.001 g scale or volumetric solution to avoid measurement error. Reference-dose heuristics are inherently uncertain and should not be treated as safe for all users. (Dose figures and this note are from Drugs.Wiki.)
| ROA | Light | Common | Strong | Heavy |
|---|---|---|---|---|
| Oral | 5-10mg | 10-30mg | 30-50mg | 50mg+ |
Sources
Oral
Dose ladder — Drugs.WikiOnset, Duration & After-effects
| ROA | Onset | Comeup | Peak | Offset | Total |
|---|---|---|---|---|---|
| Oral | 30-90 min | 1-2 hrs | 2-4 hrs | 4-8 hrs | 7.5-15.5 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)
Strong euphoria with moderate anxiolysis and sedation, mild cognitive impairment
Tolerance
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
Cross-Tolerances
Effects
Effect glossary — · full glossary
Combinations
Cross-Check Fosazepam with another substanceHelpful Links
Add to PsychonautWiki Journal
The PsychonautWiki Journal logging app doesn't include every substance. To track Fosazepam there, start adding an ingestion, search for the name, and choose to add it as a custom substance. Paste these values:
Fosazepam Source: SubstanceSearch (substancesearch.com) Oral dose (mg): threshold 2-5 · light 5-10 · common 10-30 · strong 30-50 · heavy 50+ Oral duration: onset 0.5-1.5h · come-up 1-2h · peak 2-4h · offset 4-8h · total 7.5-15.5h · after-effects 12-72h 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 ~ 20 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.
Report an issue or suggest an edit
Spotted incorrect or dangerous information, have a correction, a new study, or a useful addition for Fosazepam? Let us know. Reports are reviewed by moderators — this is not posted publicly.