Doctors often prescribe anticoagulants (blood thinners) to A-Fib patients to prevent blood clots that can result in stroke. Studies show the most commonly prescribed anticoagulant, Coumadin (warfarin), has reduced the risk of stroke by 68 percent. To reach this stage of defense, it is imperative to maintain the proper amount of Coumadin in the blood stream since too little can lead to clots and too much can lead to severe bleeding. A-Fib patients should follow their doctor’s instructions closely and monitor their blood levels regularly because many drugs, dietary supplements and foods can negatively influence blood levels.