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Midazolam (Versed) in the Emergency Department: Indications, Dosing, and Safety

Midazolam is a short-acting, water-soluble benzodiazepine widely used in the ED for sedation, anxiolysis, and seizure control. Its rapid onset and minimal active metabolites make it ideal for acute settings.

Pharmacokinetics

Onset: IV 1–2 min; IM 5–15 min; IN 5–10 min; PO 15–30 min.
Peak Effect: IV 2–3 min; IM 30 min.
Duration: Clinical sedation 30–60 min (IV); amnesia 1–2 hr.
Metabolism: CYP3A4 → 1-OH-midazolam (active, glucuronidated) → renal excretion. Half-life 1.5–3.5 hr (prolonged in hepatic impairment, elderly, obesity, drug interactions).

Common ED Indications & Dosing (Adults)

Critical Safety Considerations

Respiratory Depression: Dose-dependent; synergistic with opioids, alcohol, other sedatives. **Capnography monitoring mandatory for PSA.**
Hemodynamic Instability: Hypotension (vasodilation, reduced SVR) – caution in hypovolemia, sepsis, elderly.
Paradoxical Reaction: Agitation, disinhibition, combativeness (more in kids, elderly, developmental delay).
Amnesia: Desired for PSA; inform patient.
Contraindications: Acute narrow-angle glaucoma, severe respiratory depression, shock, known hypersensitivity.

Reversal

Flumazenil 0.2 mg IV q1min (max 1 mg then 3 mg/hr) – **Use with caution:** Precipitates withdrawal in BZD-dependent patients; lowers seizure threshold; re-sedation risk (shorter half-life than midazolam). Not routine.

Pediatric Pearls

IN route preferred for seizures (0.2 mg/kg, max 10 mg).
PSA: IV 0.025–0.05 mg/kg (max 2 mg/dose); often combined with ketamine.
Weight-based dosing essential; use Broselow tape.

Midazolam is a high-alert medication. Requires trained provider, monitoring (ETCO2, SpO2, BP, ECG), airway equipment, and reversal agent immediately available.

Emergency Rooms - Related Articles

Indication	Route	Typical Dose	Max/Notes
Procedural Sedation (PSA)	IV	0.02–0.04 mg/kg (1–2 mg) incremental q2min	Total usually ≤0.1 mg/kg; combine with opioid (fentanyl)
Acute Agitation / Chemical Restraint	IM	5 mg (10 mg if severe)	Alternative: IM ketamine 4–5 mg/kg; avoid in excited delirium (risk of respiratory depression)
Status Epilepticus (Pre-hospital / IV access delay)	IM / IN / Buccal	0.2 mg/kg (max 10 mg)	IN preferred (0.2 mg/kg, max 10 mg); faster than IM, non-invasive
Pre-intubation Sedation (RSI adjunct)	IV	0.03–0.1 mg/kg	Not an induction agent; use with etomidate/ketamine/propofol
Alcohol Withdrawal (adjunct)	IV	0.05–0.1 mg/kg q15–30min	With benzodiazepine-resistant cases; monitor for respiratory depression