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Warfarin (Coumadin®) Patient Information Sheet
By: Kristi Durret PharmD
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Warfarin - Many medications and supplements can thin the blood, and when used with warfarin, can lead to serious bleeds. Avoid unnecessary over the counter pain relievers other than acetaminophen, herbal and supplement products, and keep in mind that other prescriptions can thin the blood, for example: most antidepressants.
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What is warfarin for?
• Warfarin is an anticoagulant (also known as a blood thinner) that is meant to prevent blood clots. It is used to prevent heart attack, stroke and blood clots in your arteries and veins.

How does it work?
• Your liver makes clotting factors that help the blood to clot and stop bleeding. However, sometimes these clots can be harmful in certain medical conditions. Warfarin prevents the clotting factors that require Vitamin K from being formed which reduces the risk of dangerous blood clots in your body.

How do I take warfarin?
• Take this medication exactly as it is prescribed.
• Your dose can be affected by the environment, other medications you are taking, your diet and several other factors.
• Take each dose of warfarin at the same time each day with a full glass of water. You may take it with or without food.
• If you miss a dose take it as soon as you remember. If it is almost time for your next dose, skip the missed dose and wait until it is time to take your medication. Never double your dose.
• If you need to have any surgical procedures (including dental) while taking warfarin you may need to stop taking it before the procedure. Make sure the surgeon knows you are taking warfarin.
• Store your medication at room temperature away from heat and light and out of the reach of children.

What tests will I need to have for monitoring?
• When you are first starting warfarin and anytime you stop taking it and re-start it you will need a series of frequent blood tests to determine the appropriate dose for your body. This is called a PT/INR and it measures how fast your blood clots. Your doctor will monitor these closely to ensure you are reacting correctly.
• Do not take more or less than is recommended by your doctor at any given time. You will continue to have blood tests on a regular basis during your therapy after your dose is established to continue to assess your response.

What side effects should I know about?
• Signs of a serious allergic reaction include hives, difficulty breathing and swelling of your face, tongue, lips or throat. If this occurs contact your doctor immediately.
• Contact your doctor immediately if any of the following occur:
     o Skin discoloration anywhere on your body or temperature change, this may indicate a clot that is blocking blood flow to a part of your body
     o Purple toes or fingers
     o Pain in your stomach, back or sides
     o Severe dizziness, headache or weakness
     o Persistent diarrhea
     o Easy bruising or bleeding that will not stop
     o Pink or brown urine
     o Urinating less than usual
     o Red or black, tarry stools
     o Coughing up blood
     o Vomiting of blood that looks like coffee grounds
     o Nosebleeds or bleeding gums
     o Sudden headache, confusion, problems with vision, speech or balance
     o Sudden leg or foot pain
     o Sudden numbness or weakness, especially on one side of the body
• Other less serious side effects are more likely to occur
     o Excessive gas or bloating
     o Diarrhea, nausea or vomiting
     o Hair loss
     o Loss of appetite, weight loss
• Talk to your doctor about any side effects you experience that are bothersome to you.

Drug interactions:
• Many medications interact with warfarin and may cause an increased or decreased PT/INR (e.g. analgesics like Tylenol®, medicines for high cholesterol, antibiotics). Do not start or stop taking any medications including over the counter medications or herbal products without first asking your doctor. Always keep a list of all your medications to show your doctor and pharmacist.
• Avoid taking aspirin or NSAIDs including ibuprofen (Motrin®, Advil®), diclofenac (Voltaren®), naproxen (Aleve®, Naprosyn®), piroxicam (Feldene®), celecoxib (Celebrex®), indomethacin and others. These affect blood clotting and may cause serious bleeding in your stomach or intestines if used with warfarin.
• Avoid taking herbal products including bromelains, coenzyme Q10, cranberry, danshen, dong quai, garlic, ginkgo biloba, ginseng or St. John’s wort. Do not take any of these products without asking your doctor first. Some of these products can increase your risk of bleeding while taking warfarin.

Nutrient interactions:
• Vitamin K decreases the efficacy of warfarin. It is okay to eat foods that contain Vitamin K like liver, broccoli, brussel sprouts, spinach, collards, cabbage and other leafy green vegetables. Vitamin K is also found in pea soup, dill pickles and coleslaw. However, do not make sudden changes in your diet with these foods without telling your doctor.
• Avoid drinking alcohol as this can increase some side effects of this medication.
• Avoid eating cranberries, drinking cranberry juice or taking herbal products containing cranberries.
• Avoid smoking cigarettes or chewing tobacco.

Signs and symptoms of bleeding:
• Easy bruising
• Black, tarry stools
• Small, broken blood vessels under the skin
• Excessive bleeding from cuts or wounds
• Bleeding from the gums
• Heavy menstrual periods in women
If bleeding does occur and the cut is small, apply constant pressure to the wound until the bleeding stops. This may take up to 10 minutes. If it persists longer than this, continue to apply pressure and seek medical attention. If the cut is large apply pressure and seek medical attention immediately.

Avoiding bleeding:
• Shaving: Use an electric razor or hair removal cream instead of shaving with a razor blade.
• Teeth brushing: Use a soft bristled brush and brush and floss gently.

Avoiding falls:
• A common reason for a bleed to begin is falling.
• Take an adequate amount of calcium and Vitamin D to prevent osteoporosis which increases your risk of falling.
• Be careful when rising from a sitting or lying down position. Take time to gain your balance and allow your blood pressure to adjust to the change. If you feel lightheaded sit back down.
• Remove throw rugs from the floors in your house. These can cause you to trip.
• Repair cracks and rough edges in your driveway and sidewalk. Keep walkways clear of objects like tools and lawn equipment. Be careful when snow or ice is present.
• Always use your walker or cane if you have one. Use handrails for support while climbing stairs and using the bathroom or bathing.
• Do not attempt to climb ladders or foot stools. Ask someone else to help you obtain items that are out of reach.
If you do fall call your doctor right away, especially if you hit your head.

Other safety tips:
• Carry an ID card or wear a medical alert bracelet so that in case of emergency any care provider will know you are taking warfarin. All healthcare providers should be aware that you are taking this medication including dentists.
• If you are planning on traveling keep your medication with you at all times. Do not place in checked baggage or leave in the car.
The information provided in this website is aimed at helping people become empowered through knowledge to help protect themselves from medication related harm. You should consult with your physicians before making any changes to your prescription regimen, including herbal, supplement and over the counter products recommended by your physician(s). Increased awareness about the medications and products you are taking will help you have an effective problem solving discussion with your physician(s) and care managers.
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