Clodronate. A randomized study in the treatment of cancer-related hypercalcemia.

Malignancy-associated hypercalcemia is a common and recalcitrant problem. Current modes of therapy are often ineffective or prohibitively toxic. Clodronate disodium is a diphosphonate capable of inhibiting bone resorption resulting in a hypocalcemic effect. In this randomized, placebo-controlled study, we investigated the effect of hydration only (Rx-1) vs the effect of hydration plus either intravenously administered clodronate disodium, 4 mg/kg of body weight per day for three days (Rx-2) or intravenously administered clodronate disodium, 12 mg/kg of body weight given once only (Rx-3). By the third day of observation, Rx-2 produced a significant 2.8 mg/dL (0.70 mmol/L) reduction in serum calcium levels, whereas Rx-1 and Rx-3 did not produce a significant hypocalcemic effect when compared with baseline values. There were no toxicities observed. Intravenously administered clodronate appears to be an excellent agent for the acute treatment of malignancy-associated hypercalcemia.