Methotrexate in dermatology.

Methotrexate is a folic acid analog pioneered for use in inflammatory diseases by dermatologists, and used successfully for over 40 years for a wide variety of cutaneous diseases. In addition to its antiproliferative properties, methotrexate has other more recently recognized anti-inflammatory properties related to its effects on adenosine. Further research concerning its mechanism of action and genetic enzymatic variations suggest future possibilities for maximizing therapy and predicting adverse events. In this review the present authors will explore methotrexate's pharmacokinetics, mode of administration, dosing guidelines, side effect profile, and medication interactions. In addition, the present authors hope to offer practical guidelines for dose initiation and adjustment, and to summarize new research on its mechanism of action and implications for future therapy.