Warfarin is widely used as a preventive and therapeutic medicine for thromboembolism, and there are not a few cases in which the patients who are to undergo anticancer drug treatment are taking it. Warfarin interacts with many medicines and one should take precautions in the treatment with fluorouracil anticancer drug against the situations where the anticoagulant effect is strengthened and bleeding complications appear. I experienced a few cases in which the patients who were carefully achieving good control of combined application had serious bleeding complications when they were given Loxoprofen additionally, on which I will report.Background
The factors of bleeding complications are ‘combined application of loxoprofen, which has a high protein binding ratio, inhibits the metabolism of warfarin and strengthens the anticoagulant effect’, ‘the platelet aggregation inhibition effect of loxoprofen’, ‘furthering the bleeding tendency by loxoprofen's inhibiting COX-1 such as gastrointestinal tract ulcer’, etc.The course of the cases
The regimen is mFOLFOX, FOLFIRI and XELOX. In every case, the patient was taking warfarin orally and then added with the treatment with fluorouracil anticancer drug and the dose was changed on a timely basis, which had favorable outcome of anticoagulation treatment, and it was to such condition where loxoprofen was added. The serious bleeding occurred 12 days after taking Loxoprofen for the early cases and 18 days for the late cases, and some needed blood transfusion as PT-INR was 15.42.Issue
Loxoprofen is frequently used to control cancer-related pain and it is highly likely that patients undergoing anticancer drug treatment are administered with it. In addition to cancer-related pain, it can be also prescribed in the areas of dentistry and orthopedics. It is necessary to actively disseminate such interaction information to medical staff and patients.