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[Pharmacology](https://durgical.com/en/pharmacology/) · [Intravenous anaesthetics](https://durgical.com/en/pharmacology/classes/intravenous-anaesthetics/)

# Etomidate

Intravenous anaesthetic that barely changes blood pressure: useful to induce the unstable patient. It transiently suppresses cortisol.

Updated 2026-11-01

- Class: [Intravenous anaesthetics](https://durgical.com/en/pharmacology/classes/intravenous-anaesthetics/)
- Receptor: GABA-A receptor (α1β2γ2)
- ATC code: N01AX07

## ⚠ High-alert medication

An error with this medicine can cause serious harm: double checks and protocols are used.

◎**GABA-A receptor (α1β2γ2)**Etomidate

ⓘ The figure shows etomidate bound to the human α1β2γ2 GABA-A receptor, with GABA present.

**Target in 3D:** GABA-A receptor (α1β2γ2). PDB structure 6X3V (RCSB PDB, public domain). [View the structure at RCSB PDB](https://www.rcsb.org/structure/6X3V) · Drag to rotate · pinch to zoom

## Mechanism of action

Etomidate is an imidazole that enhances the GABA-A receptor: it increases the GABA-activated chloride current, hyperpolarises neurons and produces hypnosis in under a minute, with no analgesic effect. It depresses the heart and circulation very little. At the same time it inhibits adrenal 11-beta-hydroxylase, so cortisol and aldosterone synthesis falls for hours after a single dose.

- Enhances the GABA-A receptor chloride current
- Hypnosis in under a minute, without analgesia
- Blood pressure and cardiac output barely change
- Inhibits 11-beta-hydroxylase: cortisol falls

## Pharmacokinetics

**Distribution**
Reaches the brain quickly; redistribution limits the duration of a dose.

**Metabolism**
Rapid hepatic metabolism to inactive compounds.

**Elimination**
Mainly renal and partly biliary.

**Half-life**
About 75 minutes after the rapid initial fall.

**Onset and duration**
Usually under a minute; anaesthesia is brief.

## Indications

- Induction of general anaesthesia
- Induction in patients with haemodynamic instability or severe cardiovascular disease

## Adverse effects

### Common

- Venous pain on injection
- Myoclonus and other transient muscle movements
- Nausea and vomiting
- Hiccups

### Serious (rare, important)

- Suppression of cortisol and aldosterone production for hours, unresponsive to ACTH
- Seizures in patients with epileptogenic foci
- Brief apnoea and laryngospasm

## Contraindications

- Hypersensitivity to etomidate
- Prolonged infusion (because of adrenal suppression)

## Key interactions

**Opioids, benzodiazepines and other depressants**
Add sedation and respiratory depression.

## What is monitored

- Blood pressure, ECG and saturation
- Airway and ventilation
- In the critically ill: signs of adrenal insufficiency (refractory hypotension)

## Administration and safety

- Only for intravenous bolus injection; not used as a prolonged infusion.
- Contains propylene glycol; use a large vein to reduce pain.
- Staff trained in airway management, with resuscitation equipment available.

## Nursing care

- Before: airway equipment and oxygen ready.
- Explain that myoclonus is expected and in most cases is not a seizure.
- In the septic or critically ill patient: watch blood pressure over the following hours because of adrenal suppression.
- Prevent aspiration: it causes postoperative nausea and vomiting.

## Pregnancy and breastfeeding

There are no adequate studies in pregnant women; in animals, effects on the offspring were seen at high doses.

## Memory aid

ETOMIDATE = «Even heart, Taxes the adrenal»: calm haemodynamics, low cortisol.

## Test yourself

Think of the answer, then tap the question to see it.

## What is the main advantage of etomidate at induction?

It changes blood pressure, contractility and cardiac output very little, so it is useful in unstable patients or those with severe heart disease.

## Which enzyme does etomidate inhibit, and with what consequence?

Adrenal 11-beta-hydroxylase; cortisol and aldosterone synthesis falls for hours, unresponsive to ACTH.

## Which movements are common when etomidate is injected?

Transient muscle movements, mainly myoclonus, more common when there is pain on injection.

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## Related drugs

- [Propofol](https://durgical.com/en/pharmacology/propofol/)
- [Ketamine](https://durgical.com/en/pharmacology/ketamine/)

[← Back to the class: Intravenous anaesthetics](https://durgical.com/en/pharmacology/classes/intravenous-anaesthetics/)

Educational content on how drugs work; not a prescribing guide and no substitute for a health professional's advice. No doses are given.

Sources: [DailyMed - ETOMIDATE injection](https://dailymed.nlm.nih.gov/dailymed/drugInfo.cfm?setid=98002094-f065-4b5f-963f-2c34b5241316) (DailyMed (U.S. National Library of Medicine), 2026); Goodman & Gilman's The Pharmacological Basis of Therapeutics, 14th ed., ch. 24 (McGraw Hill, 2023); [ATCDDD - ATC/DDD Index](https://atcddd.fhi.no/atc_ddd_index/?code=N01AX07) (WHO Collaborating Centre for Drug Statistics Methodology, 2026).

## **Spotted a mistake?** We are always improving for the community. Tell us what is wrong and our team will review it. Report a mistake

Representative model, for educational purposes only.

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