Symptomatic hypocalcaemia and renal impairment associated with bisphosphonate treatment in patients with multiple myeloma.

We report three cases of severe hypocalcaemia associated with i.v. bisphosphonate treatment in patients with multiple myeloma. All patients had symptomatic hypocalcaemia, including a tonic-clonic seizure and tachyarrhythmia in one case. Two cases were associated with the development of acute renal failure, whereas the third patient had pre-existing renal impairment. We recommend that bisphosphonates be used with caution in patients with myeloma and renal impairment, that vitamin D deficiency be corrected prior to treatment (to reduce the risk of hypocalcaemia) and that serum calcium and renal function be monitored during treatment.