Nitrofurantoin-induced interstitial pulmonary fibrosis. Presentation and outcome.

Four cases of interstitial pulmonary fibrosis associated with nitrofurantoin therapy are analysed along with 45 other reported cases of this disease in order to review the presenting features and outcome and to determine the role of steroid therapy. Most patients were elderly (mean age, 66 years); women were more commonly affected (71%). All patients had been treated with nitrofurantoin for longer than six months (mean, 31 months). The usual presenting symptoms were dyspnoea and non-productive cough which had been present for periods for two weeks to six years (mean, 9.4 months). After cessation of nitrofurantoin therapy, the condition of 32 patients improved. In seven patients the symptoms remained unchanged. In one case, progressive deterioration of the condition ensued. There was no difference in outcome between patients who were treated with steroids and those who were not. Steroid therapy is probably not indicated in mild cases.