Metyrapone acts by interfering with the cytochrome P450 system and mainly affects 11b-hydroxylation. This causes a relative increase in the production of the immediate precursor steroid, 11-deoxycortisol, with a concomitant decrease in cortisol synthesis. These actions have been exploited in the development of a test of pituitaryΓÇôadrenal function which has been used clinically.
