Use of warfarin in the patient with cancer.

ing number of factors, including genetic polymorphism, dietary intake, and drug and food interactions, warfarin may be diffi cult to dose, even in the seemingly uncomplicated patient. Warfarin has been found to be safe and effective in cancer patients,3 but patients with advanced cancer have an increased risk of a supratherapeutic international normalized ratio (INR).4 Active cancer is a predictor of a lengthened time for a supratherapeutic INR to decrease to target levels.5 Additionally, maintaining an INR between 2 and 3 is more diffi cult in cancer patients than in patients without cancer.3,6 Hutten and colleagues studied venous thromboembolism (VTE) recurrence and bleeding and found that cancer patients had a sixfold higher incidence of bleeding than did patients without malignancy.6 Through the presentation of a brief case study Manuscript submitted August 22, 2006; accepted October 25, 2006.