Blood-clotting factors. xarelto® is selective... ...targeting just one critical factor, interacting with less of your body's natural blood-clotting function. don't stop taking xarelto® without talking to your doctor as this may increase risk of blood clots. while taking, you may bruise more easily, or take longer for bleeding to stop. it may increase your risk of bleeding if you take certain medicines. xarelto® can cause serious, and in rare cases, fatal bleeding. get help right away for unexpected bleeding, unusual bruising, or tingling. if you've had spinal anesthesia, watch for back pain...