BACKGROUND: Combining cyclosporin (CsA) and prednisone with mycophenolate mofetil (MMF) results in a significant reduction in the rate of biopsy-proven acute rejection after kidney transplantation. This is achieved with a standard daily MMF dosage of 2 or 3 g. Whether monitoring of the pharmacologically active metabolite mycophenolic acid (MPA) will lead to improved safety and efficacy is unclear. METHODS: We monitored MPA trough levels in 18 kidney transplant recipients treated with CsA, prednisone, and MMF (63 samples) and in 11 patients (31 samples) treated with prednisone and MMF only, in a cross-sectional study. All patients were at least 3 months after transplantation with stable graft function. All patients were treated with 2 g MMF for at least 3 months and 10 mg prednisone. RESULTS: The MPA trough levels in the CsA-treated patients were significantly lower (P<0.0001; Mann-Whitney) than those in patients on MMF and prednisone only (mean MPA levels 1.98+/-0.12 vs 4.38+/-0.40 mg/l respectively). CONCLUSIONS: Although all patients were treated with an identical MMF dose, a significant difference was found in the MPA trough levels between CsA- vs non-CsA-treated patients. This suggests that CsA influences the MPA trough level. The level at which CsA affects the MPA trough levels is unclear.

*Kidney Transplantation, Cross-Sectional Studies, Cyclosporine/*therapeutic use, Humans, Immunosuppressive Agents/*pharmacokinetics, Mycophenolic Acid/*analogs & derivatives/*blood/pharmacokinetics, Research Support, Non-U.S. Gov't, Transplantation, Homologous
hdl.handle.net/1765/9068
Nephrology, Dialysis, Transplantation
Erasmus MC: University Medical Center Rotterdam

Smak Gregoor, P.J.H, van Gelder, T, Hesse, C.J, van der Mast, B.J, van Besouw, N.M, & Weimar, W. (1999). Mycophenolic acid plasma concentrations in kidney allograft recipients with or without cyclosporin: a cross-sectional study. Nephrology, Dialysis, Transplantation. Retrieved from http://hdl.handle.net/1765/9068