Comparison of Two Forms of Hydrocortisone in Patients With Congenital Adrenal Hyperplasia

This study will test a new, extended release form of hydrocortisone called Chronocort in patients with congenital adrenal hyperplasia (CAH). People with CAH do not make enough of the adrenal hormones cortisol and aldosterone, and their adrenal glands make too much of the sex hormone androgen. Medicines called glucocorticoids (hydrocortisone, dexamethasone and prednisone) are currently used to treat CAH, but finding the best dose of these drugs that effectively lowers androgens without causing undesirable side effects, such as weight gain and slow growth rate in children, is often difficult to achieve. Adolescents and adults with CAH due to 21-hydroxylase deficiency may be eligible for this study. Children 16 years of age and older are eligible with confirmation by bone age that they are no longer growing. Participants undergo the following tests and procedures during two inpatient visits one month apart at the NIH Clinical Center: * Medical history and physical examination. * Medications: Following 7 days of Cortef (standard drug treatment for CAH), patients begin taking Chronocort on day 3 of hospitalization and continue the tablets once a day for 1 month. * Blood tests: A catheter (plastic tube) is inserted in a vein and left in place for frequent blood draws in order to avoid repeated needlesticks. Blood is drawn for chemistries, blood count, pregnancy test in women, and for serial tests (up to 26 samples in a 24-hour period) to measure hormone levels. * 24-hour urine test. * Height and weight measurements. Between the two hospitalizations, patients are contacted by NIH weekly to check for possible side effects from Chronocort. Two weeks after the first visit, patients also will have blood drawn by their regular doctor or a local clinic. A few days before the second hospitalization, patients undergo a 20-minute telephone questionnaire about energy level and well being. About 30 days after discharge from the second hospitalization, patients are followed up wi