Write a short note on Etomidate.

Pharmacology & Use

Etomidate is an intravenous induction agent (dose 0.3 mg/kg) whose outstanding feature is cardiovascular stability — it causes minimal hypotension — so it is valued for inducing haemodynamically unstable, elderly or cardiac patients. It acts via GABA_A and has a rapid onset and recovery.

Adverse Effects

Its drawbacks are notable: pain on injection and involuntary myoclonus, a high incidence of postoperative nausea and vomiting, and — most importantly — adrenocortical suppression (it inhibits 11β-hydroxylase). Even a single induction dose transiently suppresses cortisol synthesis, and infusions are not used for this reason (associated with increased mortality in the critically ill).

WHY Not Use It as an Infusion

The reason etomidate is confined to single-dose induction, despite its attractive cardiovascular stability, is its effect on the adrenal cortex: by inhibiting the enzyme 11β-hydroxylase it suppresses cortisol synthesis, and studies of continuous etomidate sedation in critically ill patients showed increased mortality attributable to this adrenal suppression. Even a single induction dose causes a measurable, transient fall in cortisol, which is why the drug is used with particular caution in septic and critically ill patients, in whom an adequate stress cortisol response may be important for survival.

Note

Because even one dose lowers cortisol, etomidate is used thoughtfully in the septic patient, in whom an intact adrenal stress response may matter — and an infusion is never used.

Cardiostable but suppresses cortisol — avoid infusions.

• Etomidate: IV induction agent (0.3 mg/kg); GABA_A; prized for cardiovascular stability.
• Ideal for haemodynamically unstable/cardiac/elderly induction.
• Adverse: pain on injection, myoclonus, PONV, and adrenal suppression (11β-hydroxylase).
• Not used as an infusion (adrenal suppression → harm in critically ill).