Etomidate

How it works

It produces rapid-onset hypnosis predominantly by enhancing inhibitory GABA-A receptor activity in the central nervous system.

Prescribing in practice

• Even a single induction dose suppresses adrenocortical steroid synthesis, so it is not used for maintenance or prolonged sedation and is used with caution in critically ill or septic patients.
• It frequently causes pain on injection and involuntary muscle movements, and is associated with a high incidence of postoperative nausea and vomiting.
• It has minimal analgesic effect, so analgesia must be provided separately, and offers relative haemodynamic stability useful in cardiovascularly compromised patients.

Monitoring

Monitor level of consciousness, oxygenation, ventilation and cardiovascular parameters during induction and recovery.

Counselling the patient

• Warn the patient that injection may sting and that brief muscle twitching can occur.
• Ensure the team is aware adrenal suppression precludes repeated or infusion use.

Evidence & guidelines

Concern over adrenal suppression with etomidate, particularly in critical illness, is well documented in the anaesthetic and intensive-care literature.