ABSTRACT
In the late 1950s, methotrexate (MTX) replaced aminopterin. Alternate dosage schedules were developed based on cell cycle information and cancer chemotherapy concepts. Patients with psoriasis involving more than 15%–20% body surface area are considered to have moderate to severe disease. MTX is indicated for the treatment of patients with moderate to severe psoriasis that is unresponsive to topical therapy and for patients with joint involvement. Until the advent of biologics, MTX was the most frequently used treatment for moderate to severe psoriasis since the 1960s. Relative contraindications to therapy with MTX are disease processes that may enhance the toxicity of MTX, particularly liver, kidney, and hematopoietic diseases. Adverse events from short-term or continued use of MTX have been relatively limited with the exception of the concern for hepatic toxicity. In the early years of MTX use, more problems were found when there was inadequate information on how to use the drug safely.
