Therapeutic dose monitoring of mycophenolate mofetil in dermatologic diseases

Abstract

Background: Mycophenolate mofetil (MMF) is used for prevention of allograft rejection in transplantation medicine. In dermatology it is used as a corticosteroid-sparing agent. The pharmacokinetics of MMF are known to vary by individual. Therapeutic dose monitoring of mycophenolic acid (MPA), the active metabolite of MMF, is used as a guide in transplantation medicine, but limited data exist on the benefit of measuring MPA levels in the management of dermatologic disease.

Objective: We sought to describe the use of MPA level monitoring in the management of dermatologic disease.

Methods: We retrospectively searched for cases of patients who were treated with MMF for a dermatologic condition at our tertiary care center, and who had at least 1 trough level measurement of MPA from January 1, 2003, through November 30, 2009.

Results: Our search identified 24 patients treated with MMF for autoimmune bullous diseases, connective tissue diseases, erythema multiforme, atopic dermatitis, or pyoderma gangrenosum who had at least 1 MPA trough level measured. The range of MPA levels in patients who responded to therapy was 1.2 to 8 μg/mL at a dose range of 1 to 3.5 g/d of MMF. Four cases were analyzed in detail to highlight the use of therapeutic dose monitoring in the management of dermatologic disease.

Limitations: This was a retrospective study.

Conclusion: We recommend monitoring MPA levels only in patients not responding to the standard 2-g/d dosage of MMF. MPA levels can help the dermatologist to increase the dose in patients who have poor absorption or to detect therapeutic noncompliance.