Calcitriol therapy in renal transplant patients with mild-moderate hyperparathyroidism

A significant number of renal transplant patients mantain high PTH levels after transplantation. The present study evaluates the efficacy of calcitriol treatment (0,5 mu g/day) for the control of secondary hyperparathyroidism in normocalcemic renal transplant patients. The study included 8 patients with normal renal graft function (creatinine < 3 mg/dl) during 32 +/- 21 months (range 16-65 months). In all patients PTH values were greater than 70 pg/ml. PTH, calcium, phosphorus, alkaline phosphatase, and creatinine were measured before and after 3.9 +/- 1.5 months of calcitriol treatment. Treatment was then discontinued and 4.1 +/- 1.9 months later (range 2-7.7 months) the biochemical parameters including PTH were reevaluated. The PTH levels and alkaline phosphatase decreased significantly after calcitriol treatment without changes in calcium and phosphorus. After the 4.1 months free of treatment the PTH values increased to levels close to the baseline values. The alkaline phosphatase remained low despite the discontinuation of treatment. During the treatment period, there was a moderate increase in serum creatinine (from 1.9 +/- 0.5 to 2.2 +/- 0.6 mg/dl; p < 0.05) and remained at this level after cesation of treatment. In conclusion, the administration of low dose of calcitriol (0.5 mu g/day) reduces PTH level in renal transplant patients with moderate secondary hyperparathyroidism.