Other interstitial pneumonitis / fibrosis

Amiodarone induced pulmonary toxicity

Topic Completed: 1 September 2011

Minor changes: 28 September 2020

Copyright: 2003-2021,, Inc.

PubMed search: amiodarone pulmonary toxicity

Elliot Weisenberg, M.D.
Page views in 2020: 994
Page views in 2021 to date: 700
Cite this page: Weisenberg E. Amiodarone induced pulmonary toxicity. website. Accessed October 25th, 2021.
Definition / general
  • Oral antiarrythmic drug, usually used long term
  • 5% - 10% of patients develop lung injury
  • Risk factors are: advanced age, higher dose therapy, lung surgery, oxygen therapy and underlying pulmonary disease; disease may occur without risk factors or at lower doses
  • Drug inhibits phospholipid degradation by lysosomes, resulting in phospholipid accumulation within cells, especially alveolar macrophages
Case reports
  • Drug withdrawal or dose reduction, corticosteroid therapy
  • May have 50% mortality if diffuse alveolar damage is present
Microscopic (histologic) description
  • Intra-alveolar exudate of finely vacuolated foamy macrophages, also present within alveolar septa
  • May have diffuse alveolar damage, cryptogenic organizing pneumonia type changes or changes of nonspecific interstitial pneumonia or desquamative interstitial pneumonia
Cytology description
  • Finely vacuolated, foamy macrophages; variable neutrophils
Electron microscopy description
  • Membrane bound cytoplasmic lamellar inclusions due to drug accumulation in the lungs
  • Morphologic findings are not specific and must be interpreted in conjunction with the clinical history
Back to top
Image 01 Image 02