Anticoagulation Clinic

The What's, Why's and What If's of Warfarin Therapy

What is Warfarin (Coumadin™)?

Warfarin is an anticoagulant ('anti' means 'against', 'coagulant' means 'blood clotting') that helps to decrease the clotting ability of the blood so that harmful clots are prevented.

Why Do I Need Warfarin?

Your medical condition may cause your blood to form clots you do not need. Although clotting is a normal body function, blood that clots too quickly can cause serious problems. Clots can break away and move from one part of your body to another. If a clot moved to your brain, it may cause a stroke.

What Else Should I Do While Taking Warfarin?

If you observe one or more of these warning signs of a stroke or 'brain attack', call a doctor or 911 right away.

• Sudden weakness or numbness of the face, arm or leg
• Sudden dimness or loss of vision, particularly in one eye
• Sudden difficulty speaking or understanding speech
• Sudden severe headache with no known cause
• Unexplained dizziness, or sudden falls, especially with any of the other signs.

(Warning signs may last a few moments and then disappear. They are signs of a serious condition that won't go away without a medical help.)

• Tell anyone giving you medical or dental care that you are taking warfarin
• Use a soft bristle toothbrush and waxed dental floss
• Avoid injury
• Refill prescriptions before running out.

How Do I Take Warfarin?

• Make sure it's the right tablet (right color)
• Check number on the tablet (mg strength)
• Use the same manufacturer consistently
• Take the tablet at the same time every day
• Take it exactly as you were told by your doctor

Why and When Do I Need Blood Tests?

Blood tests determine the warfarin dosage that you need – your warfarin dosage may not be the same as other patients.

Blood needs to be tested daily or every few days after your first dose of warfarin until your protime/INR results remain stable in the range that gives you protection against blood clots. After that, the time between blood tests will depend on how well your doctor thinks that you are responding to warfarin therapy.

A normal time for retesting is every 1-4 weeks after a stable dosage has been determined. You have a goal INR, most often between 2-3.

What is My Warfarin Dosage?

You take the dosage of warfarin that keeps you anticoagulated to an INR of between 2 and 3. Below 2, the risk of clot increases and above 4.5, the risk of bleeding increases.

What Things May Change My Protime/INR Test Results?

• Sickness eg: diarrhea, infection, fever
• Diet – stay consistent with green vegetable consumption
• Level of activity
• Other medications (prescription and non-prescription)
• No aspirin or NSAIDS – unless specifically instructed to take low dose aspirin by your physician.
• There are 26 known drug interactions – antibiotics and anti-fungals are the most important.
• Alcohol – limit your consumption to 2 drinks per day and none if you have a history of alcoholism or liver disease.
• Tell your doctor and anticoagulation clinic within 48 hours if any of the above change.

Why Do I Need to Pay Attention to My Diet?

Try to eat a healthy and balanced diet, but watch your intake of foods that are rich in vitamin K which helps blood to clot.

Vitamin K is found in most things that we eat, but is concentrated in green, leafy vegetables:

• Broccoli
• Cabbage
• Endive
• Mustard greens
• Spinach
• Brussels sprouts
• Collards
• Kale
• Parsley
• Turnip greens

Taking warfarin doesn't mean that you can't eat these foods, but you need to keep the amount that you eat steady – eat the same portion size and types on a consistent basis. Call the anticoagulation clinic within 48 hours if you change your diet.

What Should I Not Do?

• Do not take an extra pill to 'catch up'
• Do not take warfarin if you are or may become pregnant
• When you start or stop any medication notify the anticoagulation clinic within 48 hours.
• Do not experiment with health food store or alternative remedies such as vitamins or herbs until you have contacted the anticoagulation clinic.

What Should I Do If I Have:

• A serious fall or hit your head: Go to the emergency department
• Unusual black and blue marks on your skin: Call your doctor and the anticoagulation clinic, or it severe, go to the emergency room.
• Bleeding that does not stop: Press and hold the site for 5 minutes. If the bleeding does not stop, go to the emergency room.
• More bleeding than usual eg: bleeding of gums from brushing – contact the anticoagulation clinic or go to the emergency room if serious.
• Unusual vaginal bleeding or heavier menstrual bleeding: Contact the anticoagulation clinic or go to the emergency room if serious.
• Different color stools or urine than usual: Go to the emergency room immediately, even if this occurs one time only.
• Fever, sickness, diarrhea or infection longer than 48 hours: Contact your doctor first and then the anticoagulation clinic. If you have severe symptoms, go to the emergency room.
• Coughing or throwing up blood: Go to the emergency room immediately.
• Abdominal pain or any sudden worsening pain anywhere: Call your doctor and/or go to the emergency room.
• Trouble breathing, chest pain or if you feel new or increasing severe dizziness or weakness: Go to the emergency room

For all of the above, contact the anticoagulation clinic within 48 hours of the event.