Cinacalcet-induced hungry bone syndrome

Cinacalcet is a type II calcimimetic approved for treatment of secondary hyperparathyroidism in patients with end-stage renal disease. It is generally well tolerated with the most common side effects being nausea and vomiting. Symptomatic hypocalcemia is rare, and persistent hypocalcemia has not been reported to date. We present a case of a 66-year-old woman on chronic outpatient hemodialysis who was initiated on cinacalcet when her intact parathyroid hormone was 1091 pg/mL (normal 15-75 pg/dL). Two weeks later she developed diffuse muscle twitching. The patient required a 72-hour hospitalization and treatment with a continuous intravenous calcium infusion for symptomatic hypocalcemia. The intact parathyroid hormone level at this time was 176 pg/mL. This case is the first report of cinacalcet-induced prolonged and symptomatic hypocalcemia, closely resembling the hungry bone syndrome described in some patients with secondary hyperparathyroidism following surgical parathyroidectomy.