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Diazepam (Valium)

Benzodiazepineprescriptionoral · predicted

Long-acting benzodiazepine (GABA-A PAM) with rapid onset. Parent compound converted to active metabolite desmethyldiazepam (nordiazepam) with ~100-hour half-life, plus further active metabolites oxazepam and temazepam. This metabolite cascade produces extremely long duration of action, effects can persist for days. Used for anxiety, alcohol withdrawal, muscle spasm, status epilepticus, and procedural sedation. Highly lipophilic with rapid CNS penetration.

Projected serum levels — 5 mg, once daily

Diazepam (Valium)Temazepam
Diazepam (Valium) modeled serum levels, 5 mg once daily over 15 days Population-based pharmacokinetic estimate. Steady state reached after approximately 2 days. 0 2.5 5 7.5 10 Day 0 Day 4 Day 8 Day 11 Day 15 Time on a regular schedule ≈ steady state · day 2
Diazepam (Valium) modeled serum levels with a loading dose of 9.1 mg, then 5 mg once daily The first dose is larger so levels approach steady state faster. 0 2.5 5 7.5 10 Day 0 Day 4 Day 8 Day 11 Day 15 Time on a regular schedule

Maintenance schedule: 5 mg once daily (oral).

Loading schedule: 9.1 mg on day 1, then 5 mg once daily — reaching therapeutic levels sooner.

Modeled steady state after ~2 days: peak ≈ 8.0 mg, trough ≈ 3.8 mg body load. Population-based estimate over 15 days for a 5 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
predicted
Half-life
43 h
Common dose
5 mg
Suggested maximum
40 mg/day
Reference dose range
2–40 mg (single dose)
Suggested cadence
once daily
Validated against
10 mg oral — Cmax 0.40 mg/L at 1.3 h

Documented interactions

  • danger
    1,4-BDO (1,4-Butanediol) + Diazepam (Valium) Contraindicated

    1,4-BDO converts to GHB (GABA-B agonist). Diazepam (GABA-A) stacks for respiratory depression and dangerous sedation.

  • danger
    Carbamazepine (Tegretol) + Diazepam (Valium) CYP induction

    Carbamazepine (Tegretol) inducer of CYP3A4 predicted to change Diazepam (Valium) AUC by ~0.38x

  • danger
    Efavirenz (Sustiva) + Diazepam (Valium) CYP induction

    Efavirenz (Sustiva) inducer of CYP3A4 predicted to change Diazepam (Valium) AUC by ~0.26x

  • danger
    Levothyroxine (Synthroid) + Diazepam (Valium) Protein binding

    Diazepam (Valium) may displace Levothyroxine (Synthroid) from plasma protein binding sites, transiently raising free drug concentration. This drug has a narrow therapeutic index; free concentration…

  • danger
    Phenobarbital + Diazepam (Valium) CYP induction

    Phenobarbital inducer of CYP2C19 predicted to change Diazepam (Valium) AUC by ~0.50x

  • danger
    Rifampin + Diazepam (Valium) CYP induction

    Rifampin inducer of CYP3A4 predicted to change Diazepam (Valium) AUC by ~0.26x

Serum checks 223 modeled interaction pairings for diazepam (valium) across your whole stack — absorption conflicts, enzyme inhibition, and nutrient depletion included.

Research behind this entry

  1. Randomized, double-blind comparison of lorazepam and diazepam for the treatment of alcohol withdrawal delirium Saitz R et al. · Journal of General Internal Medicine, 2010 DOI

    RCT comparing benzodiazepines for alcohol withdrawal found both effective, with diazepam's longer-acting metabolites providing smoother tapering effect and fewer breakthrough symptoms.

  2. Pharmacological interventions for benzodiazepine discontinuation in chronic benzodiazepine users Baandrup L et al. · Cochrane Database of Systematic Reviews, 2018 DOI

    Cochrane review documenting the psychological and physiological dependence that develops with long-term diazepam and other benzodiazepine use, and the difficulty of tapering even with pharmacological support.

  3. Clinical pharmacokinetics of diazepam and its active metabolites Greenblatt DJ et al. · Clinical Pharmacokinetics, 1980 DOI

    Classic PK study establishing diazepam half-life of 20-70 hours (mean 43h), rapid absorption (tmax <1h), active metabolite desmethyldiazepam with 100-hour half-life, and cumulative active metabolite effect.

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