Korean J Med.  2011 Jun;80(6):729-733.

A Case of Elevated Prothrombin Time-International Normalized Ratio (PT-INR) Associated with Concurrent Use of Erlotinib and Warfarin

• Kim SK
• Park KS
• Choi SH
• Byun JH
• Woo IS
• Han CH
• Kim HL

Abstract

Erlotinib, an orally active epidermal growth factor receptor (EGFR) tyrosine kinase inhibitor (TKI), is indicated for EGFR mutation-positive patients with poor performance status. Erlotinib is also used as a second-line agent in patients who show disease progression after failure of first-line therapy. Warfarin is administered in patients with advanced cancer for the prevention or treatment of venous thromboembolism. Both erlotinib and warfarin are metabolized in the human liver primarily by the CYP3A4 enzyme system. Thus, erlotinib may inhibit the metabolism of warfarin and clinicians should pay attention to the possible interaction between the two drugs when they are administered concurrently. We report the case of a 50-year-old man who showed changes in the prothrombin time-international normalized ratio (PT-INR) after coadministration of erlotinib and warfarin.

Keyword

Erlotinib; Warfarin; Prothrombin time; Carcinoma, Non-small cell lung

MeSH Terms

Carcinoma, Non-Small-Cell Lung
Disease Progression
Humans
Liver
Middle Aged
Protein-Tyrosine Kinases
Prothrombin
Prothrombin Time
Quinazolines
Receptor, Epidermal Growth Factor
Venous Thromboembolism
Warfarin
Erlotinib Hydrochloride
Protein-Tyrosine Kinases
Prothrombin
Quinazolines
Receptor, Epidermal Growth Factor
Warfarin