Symptomatic hypocalcemia following combined calcitonin and mithramycin therapy for hypercalcemia due to malignancy

Three patients with malignant disease received the usual recommended doses of mithramycin and calcitonin, either concurrently or concomitantly, because of severe life-threatening hypercalcemia. All three patients developed severe, symptomatic hypocalcemia. The mechanisms for this phenomenon are discussed. A possible synergism between calcitonin and mithramycin may prove to be hazardous in such patients and this possibility must be kept in mind when these agents are being considered as a combination treatment for hypercalcemia.