Pulmonary lesions and autoimmune reactions after long-term nitrofurantoin treatment.

Hypersensitivity reactions in two women with pulmonary lesions, autoimmune reactions with positive antinuclear factor and liver damage following long-term nitrofurantoin treatment are discussed. One patient had taken nitrofurantoin for more than 1 year and the other for more than 2 when their symptoms appeared. They were in a very poor condition, but recovered when the drug was withdrawn. Lymphocyte transformation test in vitro showed significant blast-transformation, indicating the involvement of immunological mechanisms. Treatment with corticosteroids had not been instituted.