Methotrexate is an effective and frequently used medication for the treatment of psoriatic arthritis. Long-term therapy is usually required for effective treatment. Methotrexate side effects are a common reason for discontinuation. A Cochrane Review¹ of 6 randomized controlled trials in rheumatoid arthritis demonstrated that concomitant use of folic acid reduced gastrointestinal toxicity, abnormal transaminase elevation, and patient withdrawal symptoms from methotrexate with no reduction in efficacy. This recommendation is likely to apply to methotrexate use in other conditions such as psoriatic arthritis. Between 87.7% and 91% of patients were prescribed folic acid; a chart review of a subset of patients who did not receive a folic acid prescription showed frequent use of nonprescription, over-the-counter folic acid preparations.
- Shea B, Swinden MV, Tanjong Ghogomu E, Ortiz Z, Katchamart W, Rader T, Bombardier C, Wells GA, Tugwell P. Folic acid and folinic acid for reducing side effects in patients receiving methotrexate for rheumatoid arthritis. Cochrane Database Syst Rev. 2013 May 31;(5):CD000951.