Dexamethasone Therapy of Congenital Adrenal Hyperplasia and the Myth of the “Growth Toxic” Glucocorticoid

The use of long-acting glucocorticoids in the treatment of individuals with Congenital Adrenal Hyperplasia (CAH) has been greeted with controversy. Avoidance of dexamethasone therapy is in part due to the mistaken assumptions that dexamethasone is 30-fold more potent than hydrocortisone in suppressing adrenal activity, resulting in the overtreatment and the “growth toxic” label. However, as shown more than 50 years ago, dexamethasone is 80- to 100-fold (or greater) more potent than hydrocortisone in suppressing adrenal androgen production. When children are treated with low doses of dexamethasone once daily in the morning (0.15–0.3 mg/m(2)/day of dexamethasone versus 10–25 mg/m(2)/day of hydrocortisone), studies involving infants and children show that normal growth and skeletal maturation can be achieved, along with appropriate suppression of adrenal androgen secretion. Due to its high potency, the potential for overtreatment remains high with dexamethasone. Thus, it is imperative that dexamethasone-treated children be closely monitored.