Probabilities of Pituitary-Adrenal Responsiveness After Steroid Therapy

Abstract

Small dosages of adrenal steroids may be administered continuously for years without clinical evidence of pituitary-adrenal unresponsive-ness. Thus, the ingestion of 20 mg of hydrocortisone or related steroids for several years by 117 patients with acne, hirsutism, etc. was not attended by any events suggestive of hypopituitarism or hypoadreno-corticism. On 80 occasions these patients passed uneventfully through stressful diagnostic procedures. Unresponsiveness to intravenous mepyrapone which can be demonstrated during prolonged and uninterrupted small dosage steroid therapy is temporary and does not indicate that surgical stress will prove hazardous. Thus, the administration of hydrocortisone and then dexamethasone to 42 healthy adult males for 3 years was attended by unresponsiveness to intravenous mepyrapone during but not 5 weeks after such therapy. Fifteen surgical procedures were performed during temporary interruption of the steroid therapy without untoward event. Huge amounts of steroids can be given for at least 1 month without fear of subsequent pituitary-adrenal hypofunction. Thus, the daily ingestion of 300 mg of hydrocortisone for 30 days by 11 healthy adults did not prevent the usual responses to mepyrapone 5 weeks after completion of therapy. Our limited experiences indicate that large daily dosages may be continued for 1 year or longer before residual hypofunction can be expected in some. If large dosages of steroids are to be given for years, our data suggest that an intermittent schedule, i.e. on 3 to 5 successive days of each week, is generally not associated with pituitary-adrenal hypofunction. In Cushing''s syndrome of 7 and 8 years duration removal of the adrenal adenoma was followed by normal responsiveness to mepyrapone 6 and 15 months following surgery.