Diffuse Infiltrative Lung Disease Associated with Flecainide

We present two patients who developed subacute diffuse infiltrative lung disease while receiving flecainide for supraventricular arrhythmia. They had bilateral subpleural lung opacities on computed tomography. Bronchoalveolar lavage revealed increased numbers of lymphocytes and eosinophils, and a low CD4/CD8 ratio. Nonspecific interstitial pneumonia was documented by open lung biopsy in patient 1. The outcome was favorable after flecainide withdrawal and prednisone treatment. Drug-induced pneumonitis should be suspected in patients treated with flecainide presenting with subacute diffuse infiltrative lung disease.