MYCOPHENOLATE MOFETIL - A UNIQUE IMMUNOSUPPRESSIVE AGENT

The mechanism of action, pharmacokinetics, clinical efficacy, adverse effects, and dosage and administration of mycophenolate mofetil are re viewed. Mycophenolate mofetil is used to prevent or treat allograft re jection after solid-organ transplantation. A prodrug, mycophenolate mo fetil is rapidly hydrolyzed to mycophenolic acid after oral administra tion. Mycophenolic add inhibits de novo purine synthesis, resulting in antiproliferative effects on T and B lymphocytes. The absolute bioava ilability of mycophenolic acid is 94% for oral administration; the max imum plasma concentration occurs after two hours. Mycophenolic acid un dergoes hepatic glucuronidation to an inactive salt that is renally ex creted. Clinical trials of mycophenolate mofetil in renal transplant p atients suggest that the drug is effective for the prevention of acute rejection and as rescue therapy. Clinical data on mycophenolate mofet il therapy in liver transplant patients are too limited to permit conc lusions. Clinical trials of the drug for primary immunosuppression in heart transplant patients have not been conducted, but studies of this agent as rescue therapy suggest efficacy. Mycophenolic acid has prove d useful for long-term management of psoriasis. The most common advers e effects of mycophenolate mofetil are gastrointestinal. Nephrotoxicit y and overt hepatotoxicity have not been reported, but the drug may be linked to bone marrow suppression and certain malignancies. Mycopheno late mofetil is available as a 250-mg capsule for oral use. The recomm ended initial dosage is 1 g twice daily. Mycophenolate mofetil appears to be a useful addition to the armamentarium of immunosuppressive dru gs, particularly for kidney transplant patients, but more study is nee ded to clarify role.