BackUnderstanding Methotrexate Methotrexate is one of the most commonly prescribed arthritis medicines. Learn what to expect if you take it.Updated by Linda Rath | March 18, 2024More than 900,000 people in the U.S. take methotrexate, often as a first-line treatment for rheumatoid arthritis (RA). It’s also used at much higher doses to treat some forms of cancer. In RA and certain other autoimmune diseases, including psoriatic arthritis and juvenile idiopathic arthritis (JIA), it’s an anti-inflammatory, reducing pain and the production of inflammatory proteins. As a disease-modifying antirheumatic drug (DMARD), methotrexate can also slow joint damage and the progress of the disease. This, as well as its long track record and inexpensive price tag, explains why it’s usually the first drug prescribed for RA and JIA. How to take itMost people take methotrexate in pill form, starting at 7.5 mg to 15 mg once a week, which can be increased to a maximum of 25 mg weekly. Some rheumatologists rec...