Teriparatide Efficacy in the Treatment of Severe Hypocalcemia After Kidney Transplantation in Parathyroidectomized Patients: A Series of Five Case Reports

Abstract

BACKGROUND: Teriparatide is a recombinant human parathormone (PTH 1-34) currently approved for the treatment of osteoporosis with high risk of fracture. In this study, we analyze the efficacy and safety profile of teriparatide therapy in severe and prolonged hypocalcemia after kidney transplantation in patients previously submitted to parathyroidectomy. METHODS: The authors report results from a series of five hemodialyzed patients (mean age: 50±15 years; three female) previously submitted to parathyroidectomy to control secondary hyperparathyroidism. All patients had developed severe refractory hypocalcemia (calcium minimum levels: 5±1.4 mg/dL) early after kidney transplantation. The effect of teriparatide in calcemia and phosphatemia levels was analyzed, and variations in calcium and vitamin D analog requirements were analyzed. Secondary effects and serum creatinine changes were also ascertained. RESULTS: Teriparatide therapy was initiated 32±14 days after the development of hypocalcemia. As a result, calcemia levels increased (median±standard deviation [SD]: 6.7±0.8 vs. 8.5±0.8 mg/dL, P=0.024) allowing suspension of intravenous calcium in two patients and reduction of calcitriol doses (mean±SD: 1.1±0.38 vs. 0.55±0.27 μg/day, P=0.004). In addition, phosphatemia levels (median±SD: 5.1±1.5 vs. 3.9±0.5 mg/dL, P=0.09) and calcium carbonate requirements (mean±SD: 13.8±9.4 vs. 7.2 ±3.7 g/day, P=0.9) exhibited declining trends. No secondary effects were observed and creatinemia remained stable. CONCLUSIONS: Our data strongly suggest that refractory hypocalcemia after kidney transplantation in patients with low PTH levels can be successfully treated with teriparatide. PTH analog therapy leads to faster normalization of calcemia, permits earlier suspension of intravenous calcium supplementation, and reduces calcitriol requirements.