The most common side effect of warfarin is bleeding. This is most likely to occur if your INR is too high, and if you put yourself at risk of injury. The risk of bleeding is greatly reduced by managing your therapy well and keeping your INR inside your target range.
Even when your INR is in your target range, you may see a little bleeding, like bruises on your body, or slight gum bleeding when you brush your teeth.
Signs of slight bleeding that you may notice from time to time:
- Gum bleeding while brushing teeth.
- Occasional nose bleeds.
- Easy bruising.
- Bleeding after a minor cut that stops within a few minutes.
- Menstrual bleeding that is a little heavier than normal.
Signs and symptoms of more serious bleeding to watch for include:
- Severe bruising that gets worse.
- Any bleeding that take a long time to stop.
- Unexplained bleeding or bruising
- Menstrual bleeding that is much heavier than usual.
- Red or dark urine.
- Red or black bowel motions.
- Coughing up blood, or anything red.
- Bloody or dark stained vomit.
- Severe headache or dizziness.
- Weakness or lethargy.
- Unusual pain or swelling.
If any of the above symptoms occur you should contact your doctor immediately. If your doctor is unavailable, go to your nearest hospital emergency department.