Methotrexate in Moderate to Severe Psoriasis: Review of the Literature and Expert Recommendations

Methotrexate (MTX) is the most frequently used conventional systemic drug in the treatment of psoriasis. Despite over 50years of experience in this setting, certain aspects of the use of this drug in clinical practice are still little standardized and poorly understood. For this reason, a group of 15 experts took part in a consensus development conference to achieve consensus on a series of recommendations on the use of MTX in psoriasis. The guidelines, which were developed on the basis of a systematic review of the literature, were validated by 2 rounds of voting and categorized by level of evidence and grade of recommendation. Before MTX can be used to treat moderate to severe psoriasis, the patient must be evaluated to assess the suitability of the treatment, including consideration of vaccination status and screening for tuberculosis and pregnancy. The recommended starting dose for a patient with no risk factors is 10 to 20mg/wk, the therapeutic dose for most patients is 15mg/wk, and the maximum dose is 20mg/wk. Most patients who respond to treatment will show improvement within 8weeks. Parenteral administration of MTX is desirable when there is a risk of erroroneous dosing, nonadherence, gastrointestinal intolerance, or inadequate response to the therapeutic dose taken orally. Noninvasive methods are preferred for monitoring hepatotoxicity. MTX is a good treatment option for patients with a history of cancer, but is not recommended in patients with chronic hepatitisB infection or individuals who are seropositive for human immunodeficiency virus.