Benzodiazepine (long-acting) Pregnancy: Avoid — neonatal floppy infant syndrome, withdrawal symptoms; cleft lip/palate signal in 1st trimester (data conflicting). Specialist obstetric/psych input if essential.

Diazepam

Brand names: Valium, Diazemuls (IV emulsion), Stesolid (rectal)

Adult dose

Dose: Acute anxiety: 2 mg TDS, max 30 mg/day in divided doses, ≤4 weeks. Status epilepticus: 10 mg IV (Diazemuls) over 2 min; repeat after 10 min if needed; or 10–20 mg PR (Stesolid) if no IV access. Alcohol withdrawal (alternative to chlordiazepoxide): 10 mg QDS day 1 reducing over 5–7 days. Muscle spasm: 2–15 mg/day. Sedation pre-procedure: 5–20 mg PO 1–2 hrs before, or 0.1–0.2 mg/kg IV.

Route: Oral / IV / PR / IM (avoid — erratic absorption)

Frequency: TDS–QDS for chronic; PRN for acute

Max: 30 mg/day chronic; 30 mg cumulative IV in status epilepticus before second-line therapy

Avoid IM — slow erratic absorption. Diazemuls (lipid emulsion) is preferred IV form — reduces thrombophlebitis vs aqueous Valium. Half-life 20–100 hours (with active metabolite desmethyldiazepam) — accumulates in elderly and liver disease.

Paediatric dose

Dose: 0.3 mg/kg

Route: IV / PR

Frequency: Status epilepticus dose

Max: 10 mg per dose

Status epilepticus: 0.3 mg/kg IV (max 10 mg) or 0.5 mg/kg PR (max 20 mg). Repeat after 10 min if seizure persists. Febrile convulsions: rectal Stesolid 5 mg <3 yrs, 10 mg ≥3 yrs. APLS Pathway.

Dose adjustments

Renal

No specific adjustment but caution.

Hepatic

Reduce dose 50% in moderate impairment; AVOID in severe — accumulation, risk of hepatic encephalopathy. Use lorazepam (no active metabolites) instead.

Paediatric weight-based calculator

Patient weight (kg)

Status epilepticus: 0.3 mg/kg IV (max 10 mg) or 0.5 mg/kg PR (max 20 mg). Repeat after 10 min if seizure persists. Febrile convulsions: rectal Stesolid 5 mg <3 yrs, 10 mg ≥3 yrs. APLS Pathway.

Clinical pearls

First-line for status epilepticus IV (10 mg) or rectal (10–20 mg PR) per APLS / NICE — buccal midazolam 10 mg is now often preferred in community for convulsive seizures.
Alcohol withdrawal: equivalent to chlordiazepoxide; some centres prefer diazepam for smoother taper due to long active-metabolite half-life (less inter-dose anxiety).
DO NOT use IM — absorption is erratic and slower than oral.
Diazemuls IV (5 mg/ml lipid emulsion) reduces thrombophlebitis; aqueous Valium injection should be diluted and given slowly.
Equivalent doses: diazepam 10 mg ≈ chlordiazepoxide 25 mg ≈ lorazepam 1 mg ≈ alprazolam 1 mg ≈ temazepam 20 mg.
Falls risk in elderly is dose-related and significant — review need every 4 weeks; taper by 10% every 1–2 weeks if discontinuing chronic use.
If chronic prescription, check for misuse/diversion risk and review necessity at every consultation.

Contraindications

Severe respiratory disease, sleep apnoea
Severe hepatic impairment
Myasthenia gravis
Acute narrow-angle glaucoma
Phobic or obsessional states (relative — risk of dependence)
Pregnancy and breastfeeding (relative — neonatal effects)
Concurrent strong opioids (relative — major mortality risk)

Side effects

Sedation, drowsiness, ataxia
Anterograde amnesia
Falls and hip fractures (especially elderly)
Respiratory depression (esp. with opioids — black-box warning)
Tolerance, dependence, withdrawal seizures
Paradoxical reactions: agitation, aggression, disinhibition
Hangover effect (long t½)
Thrombophlebitis (IV — use Diazemuls emulsion)
Apnoea after rapid IV push

Interactions

Opioids: fatal respiratory depression — MHRA black-box warning
Alcohol: additive CNS / respiratory depression
CYP3A4 inhibitors (fluconazole, ritonavir, cimetidine): ↑ levels
CYP3A4 inducers (rifampicin, phenytoin, carbamazepine): ↓ levels
Other CNS depressants (gabapentinoids, antipsychotics): additive
Levodopa: theoretical reduction in efficacy

Monitoring

Sedation, respiratory rate (acute IV use)
Falls risk (elderly)
Review need every 2–4 weeks for chronic use

Reference: BNFc; BNF 90; BNF for Children 2024; NICE NG217 (Epilepsies in adults 2022); APLS Pathway; MHRA Drug Safety Update Apr 2020 (benzodiazepines + opioids); SmPC Diazemuls. Verify against your local formulary and the latest BNF before prescribing.

Curated clinical cross-links plus same-class fallbacks.

Calculators