Nonhypnotic low-dose etomidate for rapid correction of hypercortisolaemia in Cushing's syndrome

We determined the adrenostatic potential of low-dose nonhypnotic etomidate in six patients with Cushing's syndrome (ectopic Cushing's syndrome, n = 2; Cushing's disease, n = 3; bilateral adrenal adenoma, n = 1). Etomidate was given as a continuous infusion for 32 h in a dose of 2.5 mg/h (n = 5) or 0.3 mg/kg/h (n = 3), respectively. Saline was given during a control period. The responsiveness to exogenous ACTH was studied during placebo and 7 and 31 h after commencing etomidate by administration of 250 micrograms 1-24 ACTH i.v. Etomidate (2.5 mg/h) led to a consistent decrease in serum cortisol in all patients from a mean of 39.4 +/- 13.3 to 21.1 +/- 5.7 micrograms/dl after 7 h (P less than 0.05 compared with placebo). After 24 h cortisol was reduced further to a mean steady state concentration of 12.3 +/- 5.7 micrograms/dl (P less than 0.05). At the end of the infusion period the cortisol increase in response to ACTH was reduced but not abolished. In contrast, a dose of 0.3 mg/kg/h etomidate induced unresponsiveness of serum cortisol to exogenous ACTH within 7 h. However, sedation was observed in two out of three patients at this dose, while during etomidate in a dose of 2.5 mg/h no side effects were seen. We conclude that low-dose nonhypnotic etomidate reduces serum cortisol to within the normal range in patients with Cushing's syndrome.(ABSTRACT TRUNCATED AT 250 WORDS)