Respiratory function surveillance during prolonged treatment with low-dose methotrexate
Cottin, V.; Tébib, J.; Massonnet, B.; Souquet, P.J.; Bernard, J.P.
Presse Medicale 26(9): 404-406
1997
ISSN/ISBN: 0755-4982 PMID: 9137391 Document Number: 473464
Long-term low-dose methotrexate (MTX) has a proven beneficial effect in patients with rheumatoid arthritis; the main drawback being the risk of interstitial pneumonia. Although estimations have varied, in our recent prospective analysis we observed 4 cases among 124 receiving MTX for rheumatological disorders, i.e. a risk rate of 3.2% Age, sex, disease duration, administration route and daily or cumulative dose do not appear to affect risk, but recent work suggest that renal failure, concomitent use of nonsteroid anti-inflammatory drugs, smoking, past pulmonary history or radiographic anomalies as well as recent withdrawal of corticosteroids are risk factors. Pulmonary function tests can be used to detect acute disorders and regular testing has been proposed to help predicted pulmonary complications in patients receiving long-term MTX. Unfortunately, minimal variations observed to date, for example in forced vital capacity or expiratory volume, do not appear to occur prior to clinical manifestations and may be due to normal aging processes or the pathological effect of the rheumatoid disease itself. In addition, due to the proven efficacy of MTX, randomized trials against a control group not given MTX would be ethically unacceptable. We are thus still unable to predict development of secondary pulmonary complications to long-term low-dose MTX. We therefore recommend testing pulmonary function at treatment onset to establish a reference for subsequent tests performed in case of clinical manifestations during MTX therapy. Patients should be counselled to consult in case of pulmonary symptoms in order to allow diagnosis as early as possible. The most recent data also would suggest that MTX may induce infraclinical alterations of pulmonary function although their significance remains to be clarified.