Does prophylactic antibiotic administration for tooth extraction affect PT-INR in patients taking warfarin?

Abstract

Background: Various antibiotics have been reported to interact with warfarin. Reports to have investigated the effects of prophylactic antibiotic administration for tooth extraction in patients taking warfarin 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: Our results suggest that prophylactic antibiotic administration has little effect on their INR values when patients on stable warfarin therapy undergo tooth extraction. Surgeons have to take attention if the patients whose INR values are close to 3.0 before their extraction.