A 73-year-old man had been treated with
Aprindine because of
paroxysmal atrial fibrillation. On July 13, 1987, five months after the commencement of
aprindine administration, he developed
dyspnea and low grade
fever. His chest X-ray revealed multiple infiltrative shadows in both lung fields. He was treated by various
antibiotics, but the infiltrative shadows increased. BALF showed increased percentage of lymphocytes and a decrease in the OKT4/T8 ratio, and the histological findings of TBLB carried out on August 6, 1987, showed alveolitis with Masson bodies. The lymphocyte stimulation test by drugs was positive only for
aprindine. After cessation of
Aprindine administration, his complaints and laboratory data improved, but his abnormal shadow on chest X-ray did not diminish completely. Open lung biopsy was performed for differential diagnosis of BOOP, on Sep. 14, 1987. The histopathology of specimens of the lung was compatible with
drug-induced
pneumonitis. The administration of 30 mg of
prednisolone was started on Oct. 14, 1987, and the dosage was decreased gradually. The abnormal shadow on chest X-ray improved. To our knowledge, there has been no reported case of
Aprindine-induced
pneumonitis, and this could be the first report.