What is warfarin?
Warfarin is a blood thinner that is taken as a pill (Coumadin). It acts more slowly than heparin and can be used over longer periods of time.
Warfarin is used after a heart attack to reduce the risk of death, another heart attack, or stroke. It is also used to prevent blocked-vessel (ischemic) strokes if you have atrial fibrillation, blood clotting disorders, or replacement heart valves. Warfarin is also used to prevent harmful blood clots from developing in the deep veins of the lower legs and in the lungs while you are confined to bed after a stroke or heart attack and have difficulty moving.
Who might receive warfarin for stroke?
If you have had a blocked-vessel (ischemic) stroke caused by a heart attack you should be given warfarin for at least 3 months and up to 1 year. You should also be given coated aspirin at the same time in doses up to 162 mg each day.5
Warfarin reduces the chances of having a first or repeat blocked-vessel (ischemic) stroke in women with atrial fibrillation at high risk for stroke.1, 3 Women with a moderate risk for stroke may also take warfarin to prevent a stroke after discussing it with their doctor.3
In women who have already had a stroke and have atrial fibrillation, warfarin should be used to help prevent another stroke. One study of 4052 patients (39% were women) found that warfarin halved the odds of having another stroke in people with atrial fibrillation.9
Women who are eligible for a carotid endarterectomy or carotid stenting will be asked to stop taking warfarin for a few days before and after the procedure; for those few days they will take heparin to prevent blood clots.
Pregnant women with a blocked-vessel (ischemic) stroke or TIA who have replacement heart valves and are at high-risk for blood clotting disorders may be given warfarin, but because there are risks to the baby this should only be done after you and your doctor have discussed the possible risks. Warfarin can be given until the middle of the third trimester, and then replaced by heparin or LMWH until delivery.5
Who should not receive warfarin?
You should not take warfarin if you have suffered a bleeding stroke or have a history of bleeding problems. Warfarin can cause problems for the baby in pregnant women, and should only be taken after careful consideration of the risks.
What are the risks of warfarin?
The major risk of warfarin is excessive bleeding from a fall or even minor cuts such as a razor nick. If you have to take warfarin, you'll be advised to avoid activities that might cause injury. Women taking warfarin must have regular blood tests to measure the blood's ability to clot. Other possible side effects include gas, tiredness, and, rarely, purple toe syndrome (with long-term use). Purple toe syndrome occurs when the toes and sides of the feet turn a dark purple color that fades if your raise your legs; if left untreated it can cause gangrene.
If you are taking warfarin you should limit your intake of foods that contain vitamin K, a vitamin involved in blood clotting: examples include green vegetables (such as lettuce and broccoli), avocado, and egg yolks.
Warfarin Quick Reference Table
| Warfarin | |
| Generic name: | warfarin |
| Brand name: | Coumadin |
| How it is given: | Pill |
| What it is used for: |
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| You should not be treated with it if: |
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| Pregnancy/nursing: | Warfarin can cause problems during pregnancy. However, in certain situations the benefits may outweigh the risks. Discuss these risks with your doctor. |
