Metabolic effects of diphosphonate in primary hyperparathyroidism

Six patients with primary hyperparathyroidism (PHPT) and one with squamous cell carcinoma of the esophagus with parathyroid hormone excess received disodium ethane-1-hydroxy-1,1-diphosphonate (EHDP) at a daily dose of 20 mg/kg orally. During treatment, the decrease in urinary calcium, total urinary hydroxyproline, and fasting urinary calcium suggested an inhibition of bone resorption. Serum calcium intestinal absorption of calcium and urinary cyclic adenosine monophosphate (cAMP) did not change significantly. This preliminary study indicates a possible role of diphosphonates in the management of inoperable cases of primary hyperparathyroidism or pseudohyperparathyroidism.