Warfarin is an anticoagulant (blood thinner). It helps to keep blood flowing smoothly in your body by decreasing the amount of certain substances (clotting proteins) in your blood.
Warfarin is used to treat blood clots (such as in deep vein thrombosis – DVT or pulmonary embolus – PE) and/or to prevent new clots from forming in your body which can reduce the risk of stroke, heart attack, or other serious conditions.
This medication can cause serious bleeding if it affects your blood clotting proteins too much. Some of the side effects are dizziness or weakness, coughing up blood, vision changes, red or brown urine, black or bloody stool, joint pain, headache or stomach pain, severe bleeding including heavier than normal menstrual bleeding.