Heart Disease Health Center

Anticoagulants, often called blood thinners, are medicines that slow the clotting of blood. They do not actually thin the blood but increase the time it takes a blood clot to form. Anticoagulants help prevent existing blood clots from becoming larger and may be used to prevent deep vein blood clots or to treat certain blood vessel, heart, or lung conditions.

Safety tips for anticoagulants

• Take the medicine at the same time each day.
• Check with your doctor before using nonprescription drugs, especially ones that contain aspirin or other nonsteroidal anti-inflammatory drugs (such as ibuprofen or naproxen).
• Talk to your doctor before taking any vitamins, supplements, or other natural products.
• Tell any new doctors that you are taking medicine that affects how your blood clots.
• Before any surgery or test (such as a colonoscopy), talk to your doctor about whether you need to stop taking your anticoagulant for a short time before the procedure. Stopping the anticoagulant helps prevent extra bleeding during the surgery or test. Your doctor will tell you when it is safe to start taking your medicine again.
• Be alert for signs of bleeding, and call the doctor immediately if any of the following symptoms occur:
  • Blood in urine, or stools that are red or that look like tar
  • Bleeding from the nose or gums, or spitting up blood
  • New, excessive, or prolonged vaginal bleeding
  • Frequent, severe bruising or tiny red or purple spots on the skin
• To find out how often you should have blood tests, talk to your doctor about the medicines you are taking.

If you take warfarin (such as Coumadin):

• Get regular blood tests to ensure that you are taking the right amount of medicine.
• Eat a balanced diet. Don't suddenly change your intake of vitamin K-rich foods, such as broccoli, brussels sprouts, cabbage, asparagus, lettuce, spinach, and some vegetable juices. It is most important to keep a consistent level of vitamin K foods in your diet. Vitamin K can interfere with the action of warfarin, making it more likely that your blood will clot.
• Avoid excessive use of alcohol. If you drink, do so only in moderation. Alcohol may increase the effect of warfarin.
• Don't use tobacco of any kind.
• If your other doctors prescribe medicines for you, tell them that you are taking warfarin.
• Talk to your doctor before taking any vitamins, supplements, or other natural products. Do not take ginkgo biloba or garlic while using warfarin.
• Avoid activities that have a high risk for injury, such as skiing, football, or other contact sports. If you are taking warfarin, an injury could result in excessive bleeding.
• Wear a seat belt anytime you are traveling in a car.

Preventing minor bleeding while taking anticoagulants