How It Works
Warfarin helps prevent the
formation of blood clots by increasing the time it takes a blood clot to form.
This also prevents an existing clot from getting larger.
Why It Is Used
Warfarin is used to lower the
risk of stroke in people who have
atrial fibrillation. Your doctor may recommend
warfarin based on your risk factors and on whether you can take
warfarin safely. Anything that increases your risk for a disease or
problem is called a risk factor. The more risk factors you have, the greater
your risk of stroke.
Risk factors for stroke include:
Warfarin can reduce the risk of stroke in anyone with
atrial fibrillation. Even after your heart rhythm is under control, you may
still take warfarin. Some people go in and out of atrial fibrillation without
even knowing it. Taking warfarin can lower your chances of having a blood clot
or a stroke.
You will likely take warfarin for at least
3 weeks before and 1 to 3 months after cardioversion.
-
Atrial fibrillation: Should I take anticoagulants to prevent stroke?
How Well It Works
Warfarin can help reduce the risk of stroke in people who have atrial fibrillation.
Side Effects
Bleeding is the most common side effect
of warfarin.
Know the signs of bleeding
Call 911 if:
- You cough up blood.
- You vomit blood or what looks like coffee grounds.
- You pass maroon or very bloody stools.
Call your doctor right away if:
- You have new bruises or blood spots under your skin.
- You have a nosebleed that doesn't stop quickly.
- Your gums bleed when you brush your teeth.
- You have blood in your urine.
- Your stools are black and look like tar or have streaks of blood.
- You have heavy period bleeding or vaginal bleeding when you are not having your period.
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.
Warfarin may also cause a 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:
-
Warfarin: Taking your medicine safely.
Know
what to do if you miss a dose of anticoagulant.
Pregnancy. Do not take warfarin if you are pregnant or may become pregnant. If you are
taking warfarin and think you may be pregnant, call your doctor. Warfarin can cause birth defects. If you
become pregnant while taking warfarin, your doctor may recommend that you
switch to another anticoagulant medicine called heparin while you are pregnant.
Complete the new medication information form (PDF)(What is a PDF document?)
to help you understand this medication.