Methotrexate is a Disease Modifying Anti-Rheumatic Drug (DMARD) that is also known as Trexall, Folex PFS, Rheumatrex Dose Pack, and Methoxtrexate Sodium.
Methotrexate is also known as a treatment for cancer. As a cancer treatment, it is prescribed at significantly higher doses than for arthritis treatment. Methotrexate is also occasionally used to treat certain other diseases as well.
Methotrexate is understood to work by altering how the body uses folic acid (vitamin B9), a vitamin that is needed for cell growth.
Methotrexate is available in oral tablet form and in a liquid injectable form for subcutaneous (under the skin) injection.
Injected methotrexate has a number of benefits over oral methotrexate. It tends to have fewer side effects like nausea and it is absorbed by the body better and more consistently (85% absorption for injected vs. 20-80% variability for oral).
A few small studies have even suggested that the injected form of methotrexate may be a more effective treatment for Rheumatoid Arthritis.
When methotrexate works, most patients start to feel improvement after 6 to 8 weeks. The maximum effect can take 6 to 12 months. If a patient starting on methotrexate doesn't feel any effects after a 3 month "trial period" then the medication is usually stopped.
Important Tests and Risks
Methotrexate is generally a safe medication that is tolerated by most patients taking the lower dosages used to treat arthritis.
Watch Dr. Andy Thompson, a Canadian rheumatologist, introduce Methotrexate in this short video: