LONG-TERM HIGH-DOSE INTRAVENOUS CALCITRIOL THERAPY IN END-STAGE RENAL-DISEASE PATIENTS WITH SEVERE SECONDARY HYPERPARATHYROIDISM

We prospectively studied the long-term effects of intravenous calcitri ol in 17 hemodialysis patients with severe secondary hyperparathyroidi sm (HPT) for 25.7 +/- 3.4 (+/- SE) months. Calcitriol was given thrice weekly after dialysis. Subsequently, changes were made every 3-4 week s based upon serum chemistries. Total calcium and inorganic phosphorus were measured weekly; alkaline phosphatase (AP) and IRMA-PTH were mea sured monthly. Inorganic phosphate was controlled with calcium supplem ents. With calcitriol therapy both IRMA-PTH and AP decreased from 876 +/- 113 to 65 +/- 13 pg/ml (p less than or equal to 0.001) and 432 +/- 106 to 103 +/- 15 U/ml (p less than or equal to 0.001), respectively. Each patient had a reduction in IRMA-PTH and AP. Nadir IRMA-PTH occur red at 55.4 +/- 7.3 weeks. The maximum and mean maximum doses of calci triol were 8.0 and 4.1 +/- 0.4 mu g, thrice weekly, respectively. Hype rcalcemia tended to occur in those patients who were hypercalcemic pri or to the initiation of intravenous calcitriol therapy. All hypercalce mic episodes were asymptomatic and reversed either by temporary withdr awal or lowering of the calcitriol dose. Hyperphosphatemia developed i n those patients with a history of elevated serum phosphates, and was mostly related to dietary and medication noncompliance. We conclude th at intravenous calcitriol was uniformly effective and safe for the lon g-term therapy of severe HPT in ESRD. Careful attention to serum phosp hate control is required.