Nintedanib is a small molecule tyrosine kinase inhibitor that blocks receptors including platelet-derived growth factor receptor (PDGFR) α and β, fibroblast growth factor receptor (FGFR) 1–3, and vascular endothelial growth factor receptor (VEGFR) 1–3. In addition, nintedanib inhibits the kinases Lck (lymphocyte-specific protein tyrosine kinase), Lyn (protein tyrosine kinase), Src (proto-oncogene protein tyrosine kinase), and CSF1R (colony-stimulating factor receptor 1). Nintedanib competitively interacts with the adenosine triphosphate (ATP)-binding site of these kinases and blocks intracellular signaling cascades that have been shown to be involved in the pathogenesis of fibrotic tissue remodeling in interstitial lung diseases.