DESCRIPTION. COUMADIN (warfarin sodium) tablets and COUMADIN (warfarin sodium) for injection contain warfarin sodium, an anticoagulant that acts by inhibiting vitamin K⌈dependent coagulation factors. I have chronic atrial fibrillation, and I recently had a frightening attack. Luckily, my Afib attack happened at home when I was with my wife, so everything turned out OK, but I worry about what could happen if I were, for instance, driving. Atrial Fibrillation. What is atrial fibrillation? What causes atrial fibrillation? How common is AFib? How come some people with AFib don't even know it? What is Atrial Fibrillation? Atriall Fibrillation (AFib) refers to an irregular heart beat, which causes a quivering or fluttering sensation rather than the typical rhythmic pumping of the heart. I had RAI treatment on January 28, 2010 to treat Grave's disease. I have been experiencing afib for the last 90 days now. I am at 8 wks. post RAI and am still symptomatic. Eliquis (apixaban) and Coumadin (warfarin) are anticoagulants (blood thinners) used to reduce blood clotting and reduce the risk of stroke, heart attack, and systemic embolism in patients with nonvalvular atrial fibrillation. A decision aid for AFib Stroke Prevention WITH VERY HIGH RISK FOR PATIENTS WITH ATRIAL FIBRILLATION 3 BLEEDING RISK WEIGHING IMPORTANT CONSIDERATIONS Learn more about paroxysmal atrial fibrillation, persistent atrial fibrillation, and permanent atrial fibrillation to understand the progressive nature of afib. My AFib has changed over time. I am currently taking 25mg Flecinaide/Tambacour x2 per day, my specialist wanted me to take double that but this drug scares me to 'death'. I am female and 69 years old and my AFib used to be once every 6-8 months, it then progressed to once every 10 -14 days. I am Anticoagulants and antiplatelets are important for some people with afib to lower stroke risk. Learn how doctors weigh the risks and benefits of afib medications for stroke prevention.