Etomidate adrenal suppression — FRCA Primary MCQ

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HardPharmacologyEtomidate adrenal suppressionFRCA Primary

A septic 72-year-old requires emergency laparotomy and receives etomidate for induction because of cardiovascular instability. The next morning vasopressor requirements remain high despite fluids and antibiotics. Which enzyme inhibition is most relevant?

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Correct answer: E — 11β-hydroxylase

Etomidate inhibits adrenal steroidogenesis, particularly 11β-hydroxylase, reducing cortisol synthesis after even a single dose. Acetylcholinesterase inhibition would relate to neuromuscular reversal, not refractory septic shock. Cyclo-oxygenase and monoamine oxidase are unrelated to this endocrine effect. Etomidate is haemodynamically stable at induction, but its adrenal effect is an important trade-off in sepsis.

Reference: Peck, Hill & Williams Pharmacology for Anaesthesia and Intensive Care; Ganong Review of Medical Physiology