MINERALOCORTICOID REPLACEMENT IN ADDISON'S DISEASE

Abstract
Eight patients with treated Addison''s disease were studied receiving different doses of fludrocortisone together with a constant intake of glucocorticoid. Plasma renin activity (PRA), blood pressure, pulse rate and plasma K and urea concentrations were measured after 2 wk periods on each dose. In 2 patients, PRA measurements indicated that mineralocorticoid replacement therapy was inadequate. In 4 others, PRA remained normal throughout the study, even after fludrocortisone had been discontinued, suggesting that the drug was unnecessary for the maintenance of normal Na balance in these patients. Asymptomatic fludrocortisone overdosage was indicated by a low plasma K concentration, but not by PRA measurements which failed in this study to distinguish between adequate and excessive mineralocorticoid replacement.