Etidronate disodium for treating hypercalcaemia of malignancy: a double blind, placebo-controlled study

The efficacy of intravenous etidronate disodium in controlling hypercalcaemia of malignancy was evaluated in a double blind, placebo-controlled study. Twenty patients with known malignant disease and hypercalcaemia were randomly assigned on a 2:1 basis to etidronate 7.5 mg kg-1 body weight or placebo for 3-5 days. All patients received 3000 ml saline and 40 mg furosemide per day. Eighteen patients completed the study. Eleven of twelve in the etidronate group reached normocalcaemia compared to two of six in the placebo group (P = 0.05). The etidronate group showed a greater decrease in serum calcium than the placebo group (P less than 0.02). The renal calcium excretion decreased significantly in the etidronate group, but not in the placebo group. A slight increase in serum creatinine was observed in the etidronate group compared to placebo on the first day of treatment. The difference however disappeared the following days. Intravenous etidronate treatment in combination with rehydration and furosemide constitutes a safe and efficient alternative in the treatment of hypercalcaemia of malignancy, although a first approach always should be rehydration.