Calcitriol pulse therapy in patients with end-stage renal failure.

To maximize the effects of calcitriol on parathyroid glands and bone without inducing frequent episodes of hypercalcemia, two new therapeutic approaches, intravenous therapy and intermittent pulse oral administration, have been advocated. To date, detailed results of 23 studies have been reported. All clinical trials were prospective; however, none included a placebo-control group, and only one study reported on bone histology. Review of these data indicates that in principle, both intravenous and pulse oral therapy are equally efficient in decreasing serum parathyroid hormone levels. However, both approaches induce relatively frequent episodes of hypercalcemia and, to a lesser degree, hyperphosphatemia, necessitating close monitoring during therapy. In addition, a subset of patients did not respond to either therapy without clearcut characteristics that would allow them to be identified before the start of therapy. More controlled studies that include bone histology are needed to elucidate this question. At this time, it appears that patients with severe predominant hyperparathyroidism can benefit from intravenous or pulse oral therapy, which may allow them to avoid parathyroidectomy. However, further studies are needed in patients with mild to moderate secondary hyperparathyroidism to determine whether intermittent therapies are superior to daily oral therapy in preventing parathyroid gland hyperplasia and renal bone disease.