Effect of salmon calcitonin and etidronate on hypercalcemia of malignancy

Hypercalcemia of malignancy is a commonly encountered serious clinical problem that often requires aggressive therapy. In order to combine the rapid hypocalcemic effects of calcitonin with the more delayed effect of a bisphosphonate, we administered etidronate, 7.5 mg/kg/day intravenously and salmon calcitonin, 100 IU subcutaneously, every 12 hours for 3 days in 9 patients with hypercalcemia associated with malignancy. The mean serum calcium concentration fell from 3.33 +/- 0.1 mmol/liter (mean +/- SEM) to 2.88 +/- 0.1 mmol/liter within 24 hours (P less than 0.001). All patients had a fall in the serum calcium concentration of greater than 0.5 mmol/liter and it returned to normal in 7 of the 9 patients. We conclude that the combination of salmon calcitonin with etidronate more effectively lowers the serum calcium concentration in patients with hypercalcemia of malignancy then the use of either agent alone.