Imidazole Induction Agent
Pregnancy: Compatible for emergency anaesthetic induction (RSI); rapidly crosses placenta — minimise induction-delivery interval
Etomidate
Brand names: Hypnomidate
Adult dose
Dose: Induction: 0.3 mg/kg IV over 30–60 seconds
Route: IV
Frequency: Single dose for induction
Max: 0.3 mg/kg
Preferred induction agent in haemodynamically unstable patients (minimal cardiovascular depression). Single dose causes transient adrenocortical suppression — do NOT use as infusion (prolonged adrenal insufficiency). Pain on injection — give IV lidocaine 20–40 mg first.
Paediatric dose
Dose: 0.3 mg/kg
Route: IV
Frequency: Single dose
Max: 20 mg per dose
Concentration: 2 mg/mL mg/ml
As for adults: 0.3 mg/kg IV. Myoclonic movements common in children — not a sign of light anaesthesia.
Dose adjustments
Renal
No dose adjustment required
Hepatic
No dose adjustment required
Paediatric weight-based calculator
As for adults: 0.3 mg/kg IV. Myoclonic movements common in children — not a sign of light anaesthesia.
Clinical pearls
- Haemodynamic stability is the key advantage — systolic BP usually unchanged unlike propofol or thiopental
- Adrenal suppression with single dose: clinically significant in septic patients — CORTICUS study showed increased mortality with etomidate in septic ICU patients
- Do NOT use as infusion for ICU sedation — adrenal suppression leads to adrenal crisis
- Myoclonus: pretreat with fentanyl 1 mcg/kg or midazolam to reduce
Contraindications
- Adrenocortical insufficiency (known)
- Infusion use (prolonged adrenal suppression — single dose only)
- Children <10 years (limited data — not recommended by manufacturer)
Side effects
- Myoclonic movements (up to 50% — not seizures)
- Pain on injection (reduce with IV lidocaine pre-treatment)
- Nausea and vomiting
- Adrenal suppression (single dose: 6–12h; prolonged infusion: days)
- Hiccups
Interactions
- Fentanyl — reduces myoclonic activity when given before etomidate
- Other CNS depressants — additive effects
Monitoring
- Blood pressure (continuous)
- SpO2
- Cortisol if patient becomes shocked in first 24h
- ECG
Reference: BNFc; BNF; CORTICUS Study (Sprung et al, NEJM 2008); Miller's Anaesthesia; RCoA RSI Guidelines. Verify against your local formulary and the latest BNF before prescribing.
Related
Curated clinical cross-links plus same-class fallbacks.