Metabolized in the liver via the cytochrome P-450 system, tacrolimus is approved for use in liver, renal, heart, bone marrow, and other transplantations. Toxicity is similar to cyclosporine, with nephrotoxicity being a major adverse effect. Tacrolimus should not be administered concomitantly with cyclosporine. The drug inhibits nucleic acid synthesis, suppressing cell-mediated hypersensitivity and altering antibody production. Azathioprine is metabolized in the liver and erythrocytes.
Renal function has minor effects on levels.
The drug causes a dose-dependent reduction in leukocyte and platelet counts. Development of severe renal dysfunction warrants closer monitoring with possible reduction in dosage. The major toxicities are neutropenia and thrombocytopenia. Mycophenolate Mycophenolate mofetil is an antibiotic isolated from Penicillium species with immunosuppressant properties. Its mechanism of action is similar to azathioprine but does not cause as much bone marrow suppression.