BISPHOSPHONATE-INDUCED HYPOCALCEMIA: REPORT OF 3 CASES AND REVIEW OF LITERATURE

Objective: To report 3 cases of bisphosphonate-induced hypocalcemia and review the relevant literature. Methods: We present the clinical and laboratory findings in 3 cases of bisphosphonate-induced hypocalcemia, and discuss the pathophysiologic mechanisms and the pertinent literature. Results: In our first patient (case 1), symptomatic hypocalcemia developed after intravenous administration of pamidronate for management of multiple myeloma. He had vitamin D insufficiency and impaired renal function at the time of pamidronate therapy. Our second patient (case 2) presented with symptomatic hypocalcemia 12 weeks after initiation of alendronate therapy for osteoporosis. Her serum 25-hydroxyvitamin D level was low (3 ng/mL), attributable to a combination of poor vitamin D intake, limited exposure to sunlight, use of phenytoin, and previous intestinal resections. In our third patient (case 3), hypocalcemia developed on 2 different occasions, each episode occurring after intravenous administration of pamidronate...