Oral Calcitriol Therapy in Hemodialysis Patients with Secondary Hyperparathyroidism: The Effect of Dose Adjustment According to Therapeutic Responses

Lee, J S; Kang, J Y; Yoo, H S; Jung, Y O; Park, S; Lee, S K; Park, J S

Abstract

Calcitriol therapy is a mainstay for the treatment of secondary hyperparathyroidism in chronic renal failure. However, controversy exists over the appropriate route, frequency and dose of calcitriol replacement and the increased risk of hypercalcemia and hyperphosphatemia during calcitriol therapy is a main complication. To examine the effect of the therapy with low dose oral pulse therapy and dose adjustment according to therapeutic responses, we prospectively evaluated serum IRMA-PTH, alkaline phosphatase, total calcium and inorganic phosphate, bone mineral density in 17 hemodialysis patients with secondary hyperparathyroidism for 12 months. Low dose oral pulse calcitriol was initiated and subsequently the dose adjustments were made every month based upon the biochemical parameters. Total calcium and inorganic phosphate were measured every week for the first four week and then every 2 weeks; alkaline phosphatase and IRMA-PTH were measured monthly. Before and after the treatment, bone mineral density was measured by dual energy X-ray absorptiometry. With calcitriol therapy, both IRMA- PTH and alkaline phosphatase decreased from 702+/-83 to 311+/-94pg/mL(p<0.001), and from 468+/-74U/L to 201+/-57U/L(p<0.01), respectively. The mean dose of calcitriol was 3.7+/-0.5microgram per week and mean maximum doses of calcitriol was 5.6+/-0.5microgram per week. The incidence of hypercalcemia and hyperphosphatemia was 5.2% and 11.3%, respectively. The bone mineral density of lumbar spine(p=0.010) and femoral neck(p=0.017) was increased but that of distal ulnar was not. Conclusively, low dose oral calcitriol pulse therapy and dose adjustment according to therapeutic responses, effectively suppresses the secondary hyperparathyroidism as well as minimize the incidence of hypercalcemia and hyperphosphatemia.