Interv Akut Kardiol. 2008;7(6):220-224

Difficulty of anticoagulant therapy in atrial fibrillation - interactions of warfarin with drugs and food

Kateřina Lefflerová

Klinika kardiologie, Institut klinické a experimentální medicíny, Praha

Atrial fibrillation is the most common cardiac arrhythmia, which promotes trombus formation particularly in the left atrium and increases the overall risk of stroke five-fold. One of the main objectives of treating patients with atrial fibrillation is to prevent thrombo-embolism and reduce risk of stroke. Meta-analysis of large randomized trials showed risk reduction of 68 %, adjusted-dose oral anticoagulation is more effective than aspirin against stroke. The optimal intensity of oral anticoagulation in atrial fibrillation is the value of INR 2.0–2.5. Although effective, vitamin K antagonists have narrow therapeutic window, over-anticoagulation increases risk of bleeding, anticoagulant effect is affected by drugs and food containing vitamin K. There is no special „warfarin“ diet, we must recommend diet with constant vitamin K1 content, edify about possible interactions and necessity of more frequent control of INR.

In spite of difficulty, vitamin K antagonists, such as warfarin still remain the only oral anticoagulants currently recommended for the prevention of stroke in patients with a moderate to high risk of stroke.

Keywords: atrial fibrillation, thromboembolic complications, warfarin, drug and food interactions

Published: December 20, 2008  Show citation