The use of dichloromethylene diphosphonate for the management of hypercalcaemia in multiple myeloma.

We have assessed the effects of the diphosphonate, dichloromethylene diphosphonate (Cl2MDP), in 19 patients with hypercalcaemia and increased bone resorption due to myeloma. Cl2MDP (800-3200 mg daily by mouth or 300 mg daily by intravenous infusion) decreased plasma calcium and biochemical indices of increased bone resorption in 16 of 19 patients. This effect persisted for the duration of treatment (up to 14 weeks). Prolonged treatment was associated with a progressive rise in serum alkaline phosphatase and only a transient fall in hydroxyproline suggesting the stimulation of bone repair. Since myeloma is associated with significant morbidity and mortality due to progressive bone loss, these results suggest that long-term treatment of myeloma with Cl2MDP is worthy of further study.