Effect of induction of anaesthesia with etomidate on corticosteroid synthesis in man

The effects of a single bolus dose of etomidate 0.3 mg kg-1 or thiopentone 5 mg kg-1, on the synthesis of corticosteroid hormones and adrenocorticotrophic hormone (ACTH), were compared for 24 h in 12 patients, undergoing minor surgery under general anaesthesia. Following opioid premedication i.m. and general anaesthesia, plasma cortisol concentrations decreased transiently within the first hour of anaesthesia in all 12 patients. The six patients who received etomidate had statistically higher plasma 11-deoxycorticosterone concentrations at 4 and 24 h than those who had received thiopentone (P less than 0.01). Throughout the study, no difference in plasma cortisol, corticosterone or ACTH concentrations were found between the two groups. We have demonstrated a biochemical effect of a single bolus dose of etomidate consistent with incomplete inhibition of adrenocortical mitochondrial 11 beta-hydroxylase activity, but no clinically significant adrenocortical suppression.