Alterations of cyclosporin A metabolism induced by mycophenolate mofetil.

Unexpectedly lower CsA 2-h levels were found in patients who received additional immunosuppression by MMF in our center. The aim of this study is to prove whether there are differences in CsA metabolization when MMF is added to treatment. In 33 children who received an immunosuppression of prednisolone and CsA as well as in 15 children who were treated with additional MMF, C2 and C0 were taken. In 11 children, full AUC of CsA were obtained. C2 levels differed significantly (p < 0.05) between patients treated with (617 +/- 230 ng/mL) and without MMF (750 +/- 271 ng/mL) but with similar CsA dosages. C2 correlated better with the AUC than CsA levels at other time points with r = 0.95. The equation AUC = 139 + 6.17 x C2 was calculated to match best in a C2-limited sampling strategy. This formula proved to be safer than equations that had been published before. According to our findings, we suspect that MMF alters the CsA metabolism. When MMF is used in pediatric transplant recipients, either target values of CsA have to be changed or patients may require higher doses of CsA.