The magnesium included as a pharmaceutical excipient in phosphate binders might affect the serum magnesium levels of dialysis patients

Abstract

【Objectives】To calculate the phosphate binder pill burden relative to all oral drugs prescribed to dialysis patients and to examine whether the magnesium (Mg) contained in phosphate binders as a pharmaceutical excipient affects the serum Mg levels of such patients. 【Methods】The oral drugs prescribed to 520 chronic hemodialysis patients were categorized according to their pharmacological classes, and then the percentage of phosphate binders among all drugs was calculated based on the daily number of prescribed pills. The serum Mg levels of the phosphate binder-prescribed patients and non-phosphate binder-prescribed patients were compared. The relationship between the number of prescribed pills and the serum Mg level was also analyzed. In addition, we measured the Mg content of the phosphate binders using inductively coupled plasma mass spectrometry. 【Results】The mean daily pill burden was 17.8 pills/patient, and phosphate binders accounted for 35% (6.2 pills) of all pills. The serum Mg levels of the phosphate binder-prescribed patients were significantly higher than those of the non-phosphate binder-prescribed patients. In addition, the patients’ serum Mg levels were positively correlated with the number of prescribed pills. Multivariate regression analysis showed that pill number quintile was a significant independent predictor of the serum Mg level in 169 patients who were receiving monotherapy with precipitated calcium carbonate 500 mg (SANWA), the most commonly prescribed drug at our hospital. Furthermore, this drug contained 1.8 mg/g of Mg, which was much higher than the Mg concentrations of the other phosphate binders. 【Conclusion】There is a possibility that the Mg included in phosphate binders as a pharmaceutical excipient might affect the serum Mg levels of dialysis patients because of the frequent use of such pills.