Amiodarone Pulmonary Toxicity

Amiodarone, a benzofuran derivative, has proven useful in the control of serious cardiac arrhythmias. We reviewed the English language medical literature to characterize clinical, radiographic, scintigraphic, pathologic, diagnostic, and prognostic data concerning amiodarone pulmonary toxicity. Our review showed that features consistent with amiodarone pulmonary toxicity include exertional dyspnea, fever, and high sedimentation rates, usually in patients taking larger maintenance doses. Positive findings on gallium scan, foamy alveolar macrophages on lung biopsy or bronchoalveolar lavage, and resolution of abnormal chest roentgenogram upon withdrawal of amiodarone and/or institution of corticosteroid therapy support a diagnosis of amiodarone pulmonary toxicity. Conversely, maintenance doses of 400 mg or less daily, normal lung diffusing capacity and bronchoalveolar lavage or lung biopsy specimens without foamy alveolar macrophages are features that make amiodarone pulmonary toxicity unlikely. Amiodarone pulmonary toxicity should be considered in any patient who has new or clinical worsening of respiratory symptoms and/or abnormalities on chest roentgenogram. Congestive heart failure is often present in these patients and must be excluded before a diagnosis of amiodarone pulmonary toxicity can be considered. Amiodarone pulmonary toxicity also needs to be distinguished from pulmonary infection. Therefore, amiodarone pulmonary toxicity remains a clinical diagnosis relying upon a composite of clinical, radiographic, and histopathologic findings.