Influence of immunosuppressive therapy with cyclosporine A on the magnesium metabolism after kidney transplantation

During therapy with cyclosporine A (CyA) many kidney transplanted patients show a hypomagnesiaemia. The reason of this finding still is not definitively known, but it could be a renal magnesium (Mg) loss. In 125 renal transplanted patients, aged 19 - 65 (mean: 44,3) years, having been transplanted Since 1 - 16 (mean: 7,8) years, serum and urinary Mg concentrations were measured. In 21 patients treated with CyA/Prednisolon serum Mg levels were significantly (p < 0,05) lower (mean: 0,70 mmol/l) than in 86 patients treated with Azathioprine/Prednisolone (mean: 0,76 mmol/l) and in 18 patients receiving "triple-drug"-therapy (Azathioprine + CyA + Prednisolone) (mean: 0,77 mmol/l). In this 3 groups mean serum creatinine was 137,5 mu mol/l, 139 mu mol/l and 195 mu mol/l. The more pronounced renal dysfunction in the "triple-drug"-group may cause an increase in serum Mg. In CyA-treated patients low Mg levels were associated with high CyA trough levels, but not with an increased magnesiuria. The highest urinary Mg losses were found in the Azathioprine/Prednisolone group (mean: 3,59 mmol/24h). The lowest urinary Mg excretions were noted, when CyA/Prednisolone was applied (mean: 3,03 mmol/24h). These data suggest that urinary Mg excretion is not an appropriate explanation for low serum Mg levels. In order to avoid Mg deficiency serum Mg levels should be measured regularly in CyA-treated patients. If necessary, Mg should be supplemented.