This study will test the ability of extended release nifedipine (Procardia XL), a blood pressure medication, to permit a decrease in the dose of glucocorticoid medication children take to treat congenital adrenal hyperplasia (CAH).

This protocol is designed to assess both acute and chronic effects of the calcium channel antagonist, nifedipine, on the hypothalamic-pituitary-adrenal axis in patients with congenital adrenal hyperplasia. The multicenter trial is composed of two phases and will involve a double-blind, placebo-controlled parallel design. The goal of Phase I is to examine the ability of nifedipine vs. placebo to decrease adrenocorticotropic hormone (ACTH) levels, as well as to begin to assess the dose-dependency of nifedipine effects. The goal of Phase II is to evaluate the long-term effects of nifedipine; that is, can attenuation of ACTH release by nifedipine permit a decrease in the dosage of glucocorticoid needed to suppress the HPA axis? Such a decrease would, in turn, reduce the deleterious effects of glucocorticoid treatment in CAH.

Inclusion Criteria:

• diagnosed with Congenital Adrenal Hyperplasia (CAH)
• normal ECG during baseline evaluation

Exclusion Criteria:

• history of liver disease, or elevated liver function tests
• history of cardiovascular disease