COMPARISON OF THE EFFICACY OF 2 INJECTABLE FORMS OF VITAMIN-D-3 AND ORAL ONE-ALPHA IN TREATMENT OF SECONDARY HYPERPARATHYROIDISM IN PATIENTS ON MAINTENANCE HEMODIALYSIS

In the present study, we compared the efficacy of two intravenous form s of vitamin D-3 [Calcijex: 1,25(OH)(2)D-3 and One-Alpha: 1(OK)D-3] an d that of oral One-Alpha in the treatment of secondary hyperparathyroi dism in patients receiving maintenance hemodialysis. Twenty patients w ere assigned to 1 of 2 treatment groups (A and B) which were matched f or age, sex, and duration of maintenance hemodialysis. None of the pat ients included had chronic liver disease or had received drugs known t o interfere with hepatic enzymes. All patients had received a stable d ose of oral calcium and One-Alpha for a minimum period of 1 year, whic h maintained corrected serum calcium at the upper limit of the normal range. At the start of the study, oral One-Alpha was replaced by Calci jex in group A and injectable One-Alpha in group B. Treatment was main tained for 3 months (phase I). Subsequently, injectable vitamin D-3 wa s discontinued and all patients received their previous dose of oral O ne-Alpha for a period of I month. Finally, oral One-Alpha was disconti nued again and the injectable forms of vitamin D-3 were crossed over i n the 2 treatment groups for another 3 months (phase II). The results showed that the serum concentrations of 1,25(OH)(2)D-3, measured 48 h after intravenous injection of One-Alpha, were not different from that produced by an equivalent dose of Calcijex in the same group of patie nts. Furthermore, overall analysis of intact parathyroid levels during the cross-over, using ANOVA with repeated responses, indicated that t he two analogues were equipotent as regards suppression of PTH secreti on. In our study, treatment with intravenous vitamin D-3 led to signif icant suppression of PTH secretion. These results were achieved by a l ower drug dosage of vitamin D-3 and at lower trough blood levels of 1, 25(OK)(2)D-3 as compared to those of oral One-Alpha. Our findings are in favor of the early use of either forms of injectable vitamin D-3 in the treatment of secondary hyperparathyroidism.