Drug interactions in transplantation.

Cyclosporine, tacrolimus, and mycophenolate are selective immunosuppressive agents commonly prescribed to prevent organ rejection. Drug interactions that increase their blood levels could expose transplant recipients to serious side effects, while drug interactions that decrease their blood levels may cause rejection episodes as a result of inadequate immunosuppression. Cyclosporine and tacrolimus are metabolized by the cytochrome P-450 enzyme system. Drugs that induce, inhibit, or compete for the same cytochrome P-450 enzyme could affect blood levels of these immunosuppressive agents.