Interaction between capecitabine and gemcitabine with warfarin in a patient with pancreatic cancer

Gemcitabine is the only chemotherapeutic agent approved by the U.S. Food and Drug Administration (FDA) for the treatment of advanced pancreatic cancer. 5-fluorouracil or its oral pro-drug, capecitabine is the second most commonly used agent in this malignancy. Capecitabine or 5-fluorouracil is the second most common agent used either in second-line or as a radiosensitizer. Thromboembolism requiring anticoagulation is a common paraneoplastic complication in these patients. We report a patient with pancreatic cancer, challenged with maintaining the international normalized ratio (INR) with gemcitabine-capecitabine combination, and later with gemcitabine monotherapy with concomitant warfarin, as well as, a brief review of the literature. Patients with pancreatic cancer who receive warfarin and gemcitabine should be monitored for any potential drug interactions. Frequent prothrombin time and INR evaluations are suggested for anticoagulated patients receiving gemcitabine, especially when combined with capecitabine.