Warfarin is an antithrombotic agent which is used in the prevention of arterial and venous thrombosis. Dietary vitamin K can inhibit hepatic cytochrome P450 isoenzymes, exhibit drug-food interactions and thus affect the metabolism of warfarin. Fifty two year-old female patient was on warfarin treatment due to acute proximal deep vein thrombosis. Desirable INR (International normalized ratio) was maintained by 7.5 mg/day warfarin treatment. The warfarin dose was gradually increased to 20 mg/day after INR controls exhibiting insufficient doses of warfarin. Since INR was not elevated by this dose, the possibility of a food or drug interaction was considered. The patient had consumed substantial amounts of garden rocket (Eruca Sativa L.) in the last two weeks. The patient was asked to cease the consumption of this food, considering its high content of vitamin K might affect the metabolism of warfarin. Subsequently, her INR value was 2.1 with a warfarin dose of 5mg/day. Her INR was maintained within therapeutic levels with a dose of 7.5 mg/day in the repeated evaluations.

Keywords : Food-drug interactions; warfarin/pharmacology