Diazepam
Valium
Long-acting benzodiazepine
Allosteric positive modulator at GABA-A. Hypnotic, anxiolytic, anticonvulsant, skeletal-muscle relaxant. Produces highly lipid-soluble + active metabolites (desmethyldiazepam, oxazepam, temazepam) → very long total duration in elderly + chronic dosing.
Indications
- •Acute seizure / status epilepticus (when lorazepam unavailable)
- •Alcohol withdrawal (long-acting auto-tapering profile useful)
- •Skeletal-muscle spasm (back spasm, MS)
- •Procedural anxiolysis (less popular than midazolam; longer hangover)
Dosing
| Context | Adult | Pediatric |
|---|---|---|
| Status epilepticus (when lorazepam unavailable) | 5–10 mg IV slow; repeat q5–10 min, max 30 mg | 0.1–0.3 mg/kg IV (max 10 mg) |
| Alcohol withdrawal | 5–20 mg PO/IV q1–4 h CIWA-driven; long half-life self-tapers | — |
| Anxiolysis | 2–10 mg PO bid–qid | — |
Pharmacokinetics
IV onset 1–5 min (very fast — high lipid solubility). Peak <30 min IV. Half-life parent 20–50 h, metabolites 50–100 h. Hepatic CYP3A4 + CYP2C19 metabolism.
Hemodynamic effects
Mild hypotension on rapid push.
Respiratory effects
Dose-dependent respiratory depression; worse with opioids.
Side effects
- !Sedation, prolonged in elderly
- !Confusion, ataxia (Beers-Criteria flagged)
- !Respiratory depression
- !Phlebitis with IV (propylene glycol vehicle)
- !Withdrawal
Contraindications
- ×Acute narrow-angle glaucoma
- ×Severe respiratory depression
- ×Sleep apnea without ventilatory support
- ×Pregnancy (Category D)
Clinical pearls
- ★REDISTRIBUTION TRAP IN STATUS: diazepam acts within minutes (lipid solubility) but redistributes back into peripheral fat fast — clinical effect wears off in 15–30 min while metabolites accumulate. Lorazepam preferred for status because it stays at brain levels longer.
- ★ALCOHOL WITHDRAWAL: long-acting profile self-tapers — useful for inpatient detox protocols where titration discipline is hard. Liver disease shifts choice to lorazepam (no CYP).
- ★ELDERLY AVOID: Beers Criteria flags benzos generally; diazepam particularly because of metabolite accumulation. Half-life can extend past 100 h in elderly.
- ★RECTAL FOR SEIZURES (HOME): Diastat rectal gel for caregivers managing seizure clusters at home — no IV needed.
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Other drugs in Benzodiazepines & Reversal
- Midazolam
GABA-A potentiation at benzodiazepine receptor.
- Flumazenil
Competitively binds benzodiazepine site on GABA-A receptor → displaces benzo agonists → reverses sedation, respiratory depression, amnesia.
- Lorazepam
Allosteric positive modulator at GABA-A receptors → ↑frequency of Cl⁻ channel opening → membrane hyperpolarization. Hypnotic, anxiolytic, anticonvulsant, anterograde amnesia. Glucuronidated only — no CYP metabolism — useful in liver disease.
Browse all classes: /reference/drugs