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Flunitrazepam (Rohypnol)

Benzodiazepineoral · inferred

Very potent benzodiazepine (~10x diazepam potency) with rapid onset hypnotic, sedative, anxiolytic, and amnestic effects. Positive allosteric modulator at the benzodiazepine site of GABA-A. Rapid GI absorption. Long half-life (18-26h) with active metabolites contributing to prolonged sedation. CYP3A4 and CYP2C19 substrate. Notorious for drug-facilitated sexual assault — many countries have banned or severely restricted it. No medical indication in the US (Schedule I in some states, Schedule IV federally with import ban); still prescribed as hypnotic in some countries.

Projected serum levels — 0.50 mg, as needed (shown daily)

Flunitrazepam (Rohypnol)
Flunitrazepam (Rohypnol) modeled serum levels, 0.50 mg as needed (shown daily) over 15 days Population-based pharmacokinetic estimate. Steady state reached after approximately 2 days. 0 0.25 0.50 0.75 1 Day 0 Day 4 Day 8 Day 11 Day 15 Time on a regular schedule ≈ steady state · day 2
Flunitrazepam (Rohypnol) modeled serum levels with a loading dose of 0.93 mg, then 0.50 mg as needed (shown daily) The first dose is larger so levels approach steady state faster. 0 0.25 0.50 0.75 1 Day 0 Day 4 Day 8 Day 11 Day 15 Time on a regular schedule

Maintenance schedule: 0.50 mg as needed (shown daily) (oral).

Loading schedule: 0.93 mg on day 1, then 0.50 mg as needed (shown daily) — reaching therapeutic levels sooner.

Modeled steady state after ~2 days: peak ≈ 0.76 mg, trough ≈ 0.36 mg body load. Population-based estimate over 15 days for a 0.50 mg dose at a 70 kg reference body mass — the interactive app scales curves to your doses, timing, and body mass.

Key facts

Category
Benzodiazepine
Route modeled
Oral
Model confidence
inferred
Half-life
22 h
Common dose
0.50 mg
Suggested maximum
2 mg/day
Reference dose range
0.25–2 mg (single dose)
Suggested cadence
as needed (shown daily)
Validated against
1 mg oral — Cmax 0.012 mg/L at 1 h

Documented interactions

  • contraindicated
    Efavirenz (Sustiva) + Flunitrazepam (Rohypnol) CYP induction

    Efavirenz (Sustiva) inducer of CYP3A4 predicted to change Flunitrazepam (Rohypnol) AUC by ~0.19x

  • contraindicated
    Rifampin + Flunitrazepam (Rohypnol) CYP induction

    Rifampin inducer of CYP3A4 predicted to change Flunitrazepam (Rohypnol) AUC by ~0.19x

  • danger
    Carbamazepine (Tegretol) + Flunitrazepam (Rohypnol) CYP induction

    Carbamazepine (Tegretol) inducer of CYP3A4 predicted to change Flunitrazepam (Rohypnol) AUC by ~0.29x

  • danger
    Clarithromycin (Biaxin) + Flunitrazepam (Rohypnol) CYP inhibition

    Clarithromycin (Biaxin) mechanism_based of CYP3A4 predicted to change Flunitrazepam (Rohypnol) AUC by ~2.29x

  • danger
    Dasatinib (Sprycel) + Flunitrazepam (Rohypnol) CYP inhibition

    Dasatinib (Sprycel) time_dependent_inhibitor of CYP3A4 predicted to change Flunitrazepam (Rohypnol) AUC by ~2.00x

  • danger
    Diltiazem + Flunitrazepam (Rohypnol) CYP inhibition

    Diltiazem mechanism_based of CYP3A4 predicted to change Flunitrazepam (Rohypnol) AUC by ~2.29x

Serum checks 83 modeled interaction pairings for flunitrazepam (rohypnol) across your whole stack — absorption conflicts, enzyme inhibition, and nutrient depletion included.

Research behind this entry

  1. Pharmacokinetics of flunitrazepam following single dose oral administration in healthy volunteers Drouet-Coassolo C et al. · European Journal of Drug Metabolism and Pharmacokinetics, 1989

    PK study establishing flunitrazepam oral bioavailability ~85%, tmax 1h, half-life 18-26h, and active metabolite N-desmethylflunitrazepam contributing to prolonged sedation.

  2. Drug-facilitated sexual assault — a review of the forensic and clinical aspects Negrusz A, Gaensslen RE · Journal of Forensic Sciences, 2003 DOI

    Comprehensive review documenting flunitrazepam as a prototypical drug-facilitated sexual assault agent due to its rapid onset, high potency, pronounced anterograde amnesia, and ease of covert administration in beverages.

2 published studies referenced in the app, each with a plain-language summary.