@article{oai:hirosaki.repo.nii.ac.jp:00003726,
 author = {Terui, Kazufumi and Takahata, Takenori and Sato, Junya and Ishiguro, Atsushi and Itoh, Jugoh and Hayakari, Makoto and Saijo, Yasuo},
 issue = {1},
 journal = {弘前医学},
 month = {Mar},
 note = {S-1, an oral prodrug of 5-fluorouracil, has been employed in treatment of solid tumors in Japan. We report two patient cases whose international normalized ratio（INR）increased due to concomitant treatment with warfarin and S-1. In case 1, a 63-year-old man, who had taken 3.5 mg/day warfarin for dilated cardiomyopathy, had a subcutaneous hematoma in a left lower eyelid on the ninth course of combination chemotherapy with S-1 and docetaxel for metastatic gastric cancer. His INR increased to 3.68 despite careful monitoring of coagulation parameters. In case 2, a 68-year-old man, who received combination chemotherapy with S-1 and irinotecan for metastatic colorectal cancer, had to reduce the dose of warfarin twice during the same chemotherapy courses because of repeated prolongation of INR. We speculate that multiple mechanisms of unstable INR are involved in strengthening the anticoagulant effect of warfarin. Frequent monitoring of INR is required to prevent unexpected adverse events of coagulation abnormality induced by the interaction between S-1 and warfarin．, 弘前医学. 62(1), 2011, p.80-85},
 pages = {80--85},
 title = {<Case Study>Enhancement of Warfarin Anticoagulant Activity by S-1},
 volume = {62},
 year = {2011}
}