Anticoagulant medicines help prevent the formation of blood clots. People with atrial fibrillation have an increased risk of developing blood clots and having a stroke because of the changes in normal blood flow through the heart. But not everyone needs to take anticoagulants. And not everyone can take anticoagulants.

You may not be able to take anticoagulants if you:

• Have bleeding problems related to ulcers or unexplained blood in the stool.
• Have a high risk of falling.
• Are unable to take the medicine as directed.
• Have uncontrolled high blood pressure.
• Drink large amounts of alcohol.
• Have another medical condition (such as a brain tumor), a recent head injury, a history of hemorrhagic stroke, or recent surgery.

Anticoagulants are recommended for most people with atrial fibrillation who are age 65 or older and can take anticoagulant medicines safely. Anticoagulant medicines, such as warfarin, are recommended for anyone who has any high risk factors for stroke—such as previous stroke, high blood pressure, or heart valve disease—or more than one moderate risk factor—such as having diabetes or being 65 or older. Anticoagulants reduce the risk of stroke in most people who have atrial fibrillation. Talk to your doctor about whether you should take anticoagulants.

You may use aspirin if you do not have any other risk factors for stroke and you are younger than age 65.