Vitamin D therapy in hypoparathyroidism and pseudohypoparathyroidism: weight-related dosages for initiation of therapy and maintenance therapy.

The aims of this study were to determine the dose of vitamin D2 that maintains the serum calcium level within the normal range in hypoparathyroid and pseudohypoparathyroid children and to establish a safe and quickly acting dose for initiating therapy in symptomatic patients. The dose requirement for maintenance therapy was studied in 11 patients and initiation therapy was studied in five newly diagnosed hypocalcemic patients. The results show that (1) the maintenance requirement of vitamin D2 is proportional to body weight and averages 2,000 IU (50 microgram)/kg/day for children of all ages and with all types of hypoparathyroid disorders and the (2) in newly diagnosed symptomatic patients, carefully controlled administration of 8,000 IU (200 microgram) vitamin D2/kg/day for the first one to two weeks corrects hypocalcemia quickly and safely.