The importance of dosing intravenous calcitriol in dialysis patients with severe hyperparathyroidism

The current study evaluates the use of intravenous (IV) calcitriol in 10 patients with severe hyperparathyroidism (HPTH). Patients with parathyroid hormone (PTH) > 1,200 pg/m and serum P < 6.5 mg/dL were studied. Ten patients with a mean PTH of 1,826 +/- 146 pg/mL were treated for a mean of 48 weeks with a dose of IV calcitriol commensurate to the level of PTH. The initial calcitriol dose had to be increased in seven patients. The mean maximum dose of calcitriol was 3.8 micrograms thrice weekly. There was a dramatic decrease in PTH levels, and by the end of the study it was 211 +/- 48 pg/mL. Alkaline phosphatase decreased from 582 +/- 3 to 120 +/- 12 IU/L. Serum Ca and P remained unchanged in most patients. There were three episodes of hyperphosphatemia in one patient, and another had a hypercalcemic episode. In conclusion, patients with severe HPTH respond very well to IV calcitriol, provided that dosing of calcitriol is commensurate to PTH levels, and hyperphosphatemia is kept under control.