Pulmonary Fibrosis and Nitrofurantoin1–3

A 72-year-old white woman experienced the gradual development of dyspnea for 3 years, with rapid progression of symptoms in the preceding year. The patient had been treated with nitrofurantoin intermittently for 3 years and nitrofurantoin macrocrystals continuously for an additional 3 years. She had clinical, pathologic, and radiographic evidence of chronic pulmonary fibrosis and interstitial pneumonia believed to be secondary to nitrofurantoin hypersensitivity. Light and electron micrographs were consistent with this diagnosis. An immunofluorescent study negated the role of antigen-antibody complex formation as part of chronic pulmonary nitrofurantoin reaction. Treatment with prednisone improved the symptoms but did not alter the physical findings, radiographs, or pulmonary function.