Skip to Content
UW Health SMPH
American Family Children's Hospital
SHARE TEXT

Warfarin for Deep Vein Thrombosis

Examples

Generic NameBrand Name
warfarinCoumadin

How It Works

Normally, when an injury that causes bleeding occurs, the body sends out signals that cause blood to clot at the wound, and then the clot naturally breaks down as the wound heals. A person prone to abnormal clotting has an imbalance between clot formation and clot breakdown.

Warfarin prevents new clots from forming and prevents existing clots from growing by stopping the production of certain proteins that are needed for blood to clot. Warfarin does not break up or dissolve existing blood clots. Warfarin is a type of anticoagulant medicine.

Why It Is Used

Warfarin is used to prevent or treat deep vein thrombosis and pulmonary embolism.1

If you have a high risk of these problems, such as having a recent surgery, you might take warfarin for a short time, about a few weeks.

If you have had deep vein thrombosis or pulmonary embolism, you might take warfarin for a longer time, such as 3 months or longer. The length of time will vary based on your health.

How Well It Works

Warfarin reduces the chance that a new blood clot will form or that an existing blood clot will get larger.

Side Effects

All medicines have side effects. But many people don't feel the side effects, or they are able to deal with them. Ask your pharmacist about the side effects of each medicine you take. Side effects are also listed in the information that comes with your medicine.

Here are some important things to think about:

  • Usually the benefits of the medicine are more important than any minor side effects.
  • Side effects may go away after you take the medicine for a while.
  • If side effects still bother you and you wonder if you should keep taking the medicine, call your doctor. He or she may be able to lower your dose or change your medicine. Do not suddenly quit taking your medicine unless your doctor tells you to.

Allergic reaction

Call 911 or other emergency services right away if you have:

  • Trouble breathing.
  • Swelling of your face, lips, tongue, or throat.

Call your doctor if you have:

  • Hives.

Bleeding

Call 911 or other emergency services right away if you have:

  • A sudden, severe headache that is different from past headaches. (It may be a sign of bleeding in the brain.)

Call your doctor now or seek immediate medical care if you have:

  • Any abnormal bleeding, such as:
    • Nosebleeds.
    • Vaginal bleeding that is different (heavier, more frequent, at a different time of the month) than what you are used to.
    • Bloody or black stools, or rectal bleeding.
    • Bloody or pink urine.

If you are injured, apply pressure to stop the bleeding. Realize that it will take longer than you are used to for the bleeding to stop. If you can't get the bleeding to stop, call your doctor.

Other side effects of warfarin include:

  • Skin rash.

See Drug Reference for a full list of side effects. (Drug Reference is not available in all systems.)

What To Think About

When you take warfarin, you need to take extra steps to avoid bleeding problems.

  • Get regular blood tests.
  • Prevent falls and injuries.
  • Eat a steady diet, and pay attention to foods that contain vitamin K.
  • Tell your doctors about all other medicines and vitamins that you take.

For more information, see:

Click here to view an Actionset. Warfarin: Taking Your Medicine Safely.

Know what to do if you miss a dose of anticoagulant.

Taking medicine

Medicine is one of the many tools your doctor has to treat a health problem. Taking medicine as your doctor suggests will improve your health and may prevent future problems. If you don't take your medicines properly, you may be putting your health (and perhaps your life) at risk.

There are many reasons why people have trouble taking their medicine. But in most cases, there is something you can do. For suggestions on how to work around common problems, see the topic Taking Medicines as Prescribed.

Advice for women

If you are pregnant, do not take warfarin. Warfarin can cause miscarriage or birth defects. If you are taking warfarin, talk to your doctor about how you can prevent pregnancy.

If you think you might be pregnant: Call your doctor. If you are pregnant, you will take heparin during your pregnancy.

If you plan on getting pregnant: Talk with your doctor. You and your doctor will decide which medicine you will take—warfarin or heparin—while trying to get pregnant.

Checkups

Follow-up care is a key part of your treatment and safety. Be sure to make and go to all appointments, and call your doctor if you are having problems. It's also a good idea to know your test results and keep a list of the medicines you take.

Complete the new medication information form (PDF) (What is a PDF document?) to help you understand this medication.

References

Citations

  1. Antithrombotic drugs (2011). Treatment Guidelines From The Medical Letter, 9(110): 61–66.

Credits

By Healthwise Staff
E. Gregory Thompson, MD - Internal Medicine
Jeffrey S. Ginsberg, MD - Hematology
Last Revised August 9, 2013

This information does not replace the advice of a doctor. Healthwise, Incorporated disclaims any warranty or liability for your use of this information. Your use of this information means that you agree to the Terms of Use. How this information was developed to help you make better health decisions.

© 1995-2014 Healthwise, Incorporated. Healthwise, Healthwise for every health decision, and the Healthwise logo are trademarks of Healthwise, Incorporated.