warfarin interferes with at least 6 of your body's natural blood-clotting factors. xarelto® is selective, targeting just one critical factor. for afib patients well managed on warfarin, there is limited information on how xarelto® compares in reducing the risk of stroke. don't stop taking xarelto® without talking to your doctor, as this may increase your risk of stroke. while taking, you may bruise more easily or take longer for bleeding to stop. xarelto® can cause serious, and in rare cases, fatal bleeding. it may increase your risk of bleeding if you take certain medicines. get help right away for unexpected bleeding or unusual bruising. do not take xarelto® if you have an artificial heart valve or abnormal bleeding. before starting, tell your doctor about all planned medical or dental procedures and any kidney or liver problems. learn all you can to help protect yourself from a stroke. talk to your doctor about xarelto®.