Variation in absorption and half-life of hydrocortisone influence plasma cortisol concentrations

Summary Background Hydrocortisone therapy should be individualized in congenital adrenal hyperplasia (CAH) patients to avoid over and under replacement. We have assessed how differences in absorption and half‐life of cortisol influence glucocorticoid exposure. Patients and Methods Forty‐eight patients (21 M) aged between 6·1 and 20·3 years with CAH due to CYP21A2 deficiency were studied. Each patient underwent a 24‐h plasma cortisol profile with the morning dose used to calculate absorption parameters along with an intravenous (IV) hydrocortisone (15 mg/m2 body surface area) bolus assessment of half‐life. Parameters derived were maximum plasma concentration (Cmax), time of maximum plasma concentration (tmax), time to attaining plasma cortisol concentration