[Withdrawing corticosteroid therapy: the stress of the last milligrams...]

Suppression of the hypothalamo-pituitary-adrenal axis (HPA) is a classic complication of corticosteroid therapy. There is some controversy over the conditions necessary to recover normal HPA activity. Most agree that the total duration of treatment, the maximal dose, the total cumulative dose and the the rate of withdrawal are all important factors in predicting HPA suppression. Recent studies provide evidence contradicting this opinion. It is now demonstrated that HPA activity is completely recovered as soon as the prednisone dose falls below 5 mg per day, that adrenal function is totally blocked for doses above 7.5 mg per day, and that an intermediary response to synactene is obtained for daily doses of 7.5 to 5 mg. It is thus reasonable to conclude that corticosteroid therapy can be safely withdrawn when the daily dose is less than 5 mg and, if a higher dose is given, a temporary increment would be indicated in case of stress.