Does tooth extraction and perioperative medication affect PT-INR of patients taking warfarin?

Abstract

Background: Various antibiotics and analgesics have been reported to interact with warfarin. Reports that investigate the effects of medication taken for just a few days during tooth extraction on the prothrombin time-international normalized ratio (PT-INR) are rare. Methods: A total of 110 patients receiving long-term stable warfarin therapy underwent tooth extraction without interruption of warfarin treatment. INR values were measured one month before the tooth extraction, the day of the extraction, and one week after the extraction. We investigated the changes of INR values between the day of extraction and one week after the extraction, as well as the various risk factors for increases in INR values.Results: Before and after tooth extraction, the number of patients taking cefcapene pivoxil, amoxicillin, and azithromycin was 57, 36, and 8, respectively. Nine patients were administered ampicillin before tooth extraction and received amoxicillin after their tooth extraction. One week after tooth extraction, the INR values increased beyond the therapeutic range in 3 out of 110 patients (2.7%). The INR values before tooth extraction in these three patients were close to 3.0. The INR value increased by more than twice as much in 1 of 110 patients (0.9%).Conclusion: When a tooth extraction is performed in patients taking warfarin, certain factors could increase the INR, such as interaction between warfarin and antibiotics or analgesics, post-extraction inflammation or infection, and eating disorders due to post-extraction pain. However, our results suggest that it has little effect on the INR values one week after extraction.