Mycophenolate mofetil pharmacokinetics in transplant patients receiving cyclosporine or tacrolimus in combination therapy

Mycophenolate mofetil is a highly effective immunosuppressant drug used in the prophylaxis of organ rejection in combination with cyclosporine or tacr olimus and corticosteroids. The present study is a retrospective data analy sis of the routinely estimated mycophenolic acid plasma trough levels in 60 transplant patients (kidney, n=49; lung, n=11) receiving mycophenolate mof etil in combination with prednisone and cyclosporine (n=45) or tacrolimus ( n=15). Coadministration of cyclosporine instead of tacrolimus resulted in a significant increase of median (rang) of the ratio of dose-ro-concentratio n 0.92 (0.11-8.33) (n=167) versus 0.38 (0.11-14.28) (n=66); P<0.0001. No co rrelation was seen between mycophenolate mofetil dose and mycophenolic acid trough concentrations. The dose-to-concentration in cyclosporine-treated p atients increased significantly (P<0.0001) as the cyclosporine level increa sed, suggesting a possible interaction between mycophenolate mofetil and cy closporine. No correlation was seen between dose-to-concentration and tacro limus blood levels (Px0.215). Further studies are necessary to investigate this issue.