Clinical evaluation of chronic nephrotoxicity of long-term cyclosporine A treatment in adult patients with steroid-dependent nephrotic syndrome.

Aim: Chronic nephrotoxicity of long-term cyclosporine A (CsA) treatment is a matter of concern in patients with steroid-dependent nephrotic syndrome (SDNS). Methods: Twenty-eight adult NS patients (25, minimal-change nephrotic syndrome (NS); three, focal-segmental glomerulosclerosis) were divided into three groups. Group A was continuously treated with CsA for more than 5 years (143 +/- 40 months, 1.3 +/- 0.4 mg/kg per day at final analysis, n = 12); group B had been previously treated with CsA (70 +/- 27 months, n = 6); and group C had been treated with corticosteroids alone (n = 10). The clinical variables related to chronic CsA nephrotoxicity were examined. Results: In groups A and B, estimated glomerular filtration rate decreased from 86 +/- 22 and 107 +/- 17 to 83 +/- 23 and 88 +/- 13 mL/min per 1.73 m(2), respectively, at final analysis (both P < 0.05). Serum magnesium levels in group A were significantly lower than those in group B or C (A, 1.78 +/- 0.16 mg/dL; B, 2.00 +/- 0.14 mg/dL; C, 2.03 +/- 0.10 mg/dL; A vs B, C, P < 0.01), and a significant correlation between these and the duration of CsA treatment was found (r = -0.68, P < 0.001). There was a trend towards a correlation between the duration of CsA administration and urinary alpha(1)-microglobulin (r = 0.38, P = 0.07). Conclusion: Mild decrease in renal function and hypomagnesemia were found in adult SDNS patients with long-term CsA treatment. Careful monitoring of renal function, blood pressure and serum magnesium levels is necessary.