Efficacy and safety of calcium acetate-magnesium carbonate in the treatment of hyperphosphatemia in dialysis patients

A phosphate binder combining calcium and magnesium offers an interesting therapeutic option to control hyperphosphatemia in dialysis patients. We investigated the effectiveness and tolerance of calcium acetate-magnesium carbonate (Ca-Mg). This is a 16-week prospective study including 16 dialysis patients. After an initial two-week washout period, serum phosphorus (sPho) ≥1.8 mmol/L, serum calcium (sCa) ≤2.6 mmol/L, and serum magnesium ≤1.5 mmol/L were the main inclusion criteria. The initial dose of Ca-Mg depended on sPho level and was titrated for every two weeks to have a sPho ≤ 1.8 mmol/L. A second two-week washout period followed the 12 weeks of treatment. Ca-Mg significantly reduced the mean sPho levels from 2.14 to 1.75 mmol/L by the end of the 12-week treatment period (P <0.006). Two weeks after the completion of the Ca-Mg study, the mean sPho levels increased to 2.2 mmol/L. The mean sCa levels did not significantly change during the Ca-Mg trial. The mean serum intact parathyroid hormone declined significantly from 446 pg/mL at the beginning of the study to 367 pg/mL at the end of the 12-week treatment period (P = 0.0002). Digestive tolerance was good in all patients which allowed good compliance. There were no episodes of hypercalcemia. However, six patients had a moderate hypermagnesemia (21 episodes) requiring adjustment of treatment dose. The Ca-Mg proved to be effective in the control of hyperphosphatemia in dialysis patients with good clinical and biological tolerance. Thus, in patients with hypercalcemia or poor tolerance to calcium carbonate, Ca-Mg might be a good alternative.