A recent 10-year study has reversed what we thought was a pulmonary disorder caused by a drug called methotrexate (MTX). This drug is used in many conditions, but one in particular has given pulmonary physicians and rheumatologists difficulty for some time.
Rheumatoid arthritis (RA) can be a crippling and painful disease with many findings that are unassociated with the joint symptoms most people associate with this condition. Methotrexate has been used for many years to treat patients with RA in the hopes of reducing inflammation in the joints and relieving deformity and pain. Many patients with RA have been helped with this drug, but one side effect was thought to be a scarring of the lung tissue in some individuals.
The concern over this potential scarring effect of MTX was made worse because RA, itself, can also cause scarring in the lung tissue. When patients with RA who were taking MTX were found to have lung tissue scarring, pulmonary physicians often were asked to determine what the cause was – RA or MTX. This was not an easy distinction to make, and often the MTX was stopped, leaving the patient with increased RA symptoms and exposure to drugs with even greater side effects.
The 10-year study reported from England, firmly stating that MTX does not cause chronic pulmonary fibrosis and the drug should not be stopped when this scarring disease is found. The culprit is the rheumatoid arthritis and treatment should be continued with MTX, and possibly advanced.