Effect of Sevelamer Hydrochloride on the Serum Calcitriol Concentration in Hemodialysis Patients

Back ground: There are no published clinical data in hemodialysis (HD) patients with mineral bone disorder (CKD-MBD) regarding the effect of sevelamer hydrochloride on the absorption of the oral calcitriol. Objectives: The aim of the present study was to determine the association of the sevelamer hydrochloride and serum 1-25(OH)2D concentration during oral calcitriol therapy. Methods: This was a before-and-after study in HD patients. Forty-six patients co-administered with phosphate-binder and calcitriol for CKD-MBD therapy took lanthanum carbonate (LC) and sevelamer hydrochloride (SH) for 4 weeks, respectively with calcitriol. The serum 1-25(OH)2D concentration was assessed after each period. Results: Serum 1-25(OH)2D concentration was significantly reduced with co-administration of SH compared to LH (mean, calcitriol with LC→SH: 19.9 pg/ml → 14.2 pg/ml, p < 0.001). The mean dosage of calcitriol, LH and SH was 0.32 mcg/day, 1443 mg/day and 3897 mg/day, respectively. Conclusion: SH significantly reduced serum 1-25(OH)2D concentrations after oral calcitriol administration compared to LH in HD patients. When we use SH as a phosphate binder with calcitriol for HD patients with CKD-MBD, we should consider the inhibitory effect of SH on oral calcitriol absorption.