Methotrexate for Rheumatoid Arthritis: Long Term Use Considered Safe

The results of a recent study published in the Annals of the Rheumatic Diseases indicate that the drug methotrexate (MTX) appears to be safe for long term treatment of rheumatoid arthritis.  This conclusion was based on data collected from 88 studies that involved patients treated with methotrexate for at least 2 years.

Methotrexate is classified as a disease-modifying anti-rheumatic drug also known as a DMARD.  Methotrexate had been used to treat psoriasis and cancer prior to its approval by the U.S. Food & Drug Administration in 1988 to treat rheumatoid arthritis. It is also used to treat other autoimmune diseases including ankylosing spondylitis, psoriatic arthriis, lupus and vasculitis. It can take from 6 to 12 weeks to feel the full effect of this medication.  Taken once weekly via either 2.5 mg tablets or self injection,  methotrexate blocks certain enzymes that affects the production of folic acid which is necessary for growing cells. Therefore it is necessary to take folic acid suppliments while on methotrexate.

It is important to avoid drinking alcohol while using this medication because of the increased risk of liver damage.  Methotrexate can cause abnormal liver function so it is necessary to have blood work monitoring done every 8 weeks. The 88 studies concluded that 13% of people taking methotrexate experienced elevated liver enzymes however only 3.7% had to stop using the drug due to liver toxicity. Other side effects include nausea, vomiting ( may be based on the dosage), mouth sores, rash, diarrhea, blood count abnormalities,  persistent dry cough, unexplained shortness of breath, cirrhosis of the liver ( rarely), gradual hair loss, and sensitivity to sunlight.  Some over the counter and prescription medications may increase the toxicity of methotrexate so it is important to check with your doctor or pharmacist before taking any additional medication. Methotrexate can cause birth defects and can cause complications during pregnancy.  It should not be taken if you plan on starting a family.

Patients in the study experienced side effects but usually mild. Methotrexate rates of discontinuation were less than gold, sulfasalazine and penicillamine but more than plaquenil in this study.

Of the 88 studies only 2 assessed the relationship between methotrexate and cardiovascular disease. One study concluded that there was no increased risk of cardiovascular disease, the other suggested that there may be a reduced risk.  There was no increased risk of infections linked to methotrexate.