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Blood Thinners: What You Should Know 

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What is a blood thinner?

There are two basic types of blood thinners: antiplatelets and anticoagulants.

  • Antiplatelet drugs keep blood cells (or platelets) from sticking together and help lower the risk of heart attack or stroke. Aspirin is a common antiplatelet that you can buy over-the-counter. Talk to your doctor before taking aspirin to lower your risk of stroke or heart attack.
  • Anticoagulants keep proteins in the blood from causing clots. Common forms of these drugs are heparin in IV form and warfarin in pill form. Some brand names for warfarin are Coumadin®, Dicumarol® and Miradon®. Your doctor may have you take this kind of medicine if you have a risk for clots forming in your leg veins, an abnormal heart rhythm or an artificial hart valve.

Why do I need to take a blood thinner?

If your doctor prescribes a blood thinner, this is likely because you are at risk for blood clots. Blood clots block blood flow in your arteries and veins, even those in your heart and brain. These clots can cause many health problems, such as heart attack and stroke.

Your doctor may have you take a blood thinner if you:

  • Have had recent surgery
  • Have had or are at risk for a stroke or heart attack
  • Have a blood vessel disease or heart disease
  • Have an abnormal heart rhythm known as atrial fibrillation
  • Have poor blood flow
  • Have blood that tends to clot
  • Have had a blood clot
  • Have had heart problems since birth

Do blood thinners really thin my blood?

Blood thinners do not really make your blood thin. Instead, they work by keeping blood clots from forming and growing in your veins or arteries. They help your body lengthen the time it takes for blood clots to form.

To form a blood clot, specific proteins must be in your blood. These proteins are made by your liver. Eating foods with vitamin K, such as spinach and kale, helps your liver make these proteins. Blood thinners block the formation of clotting proteins that require vitamin K.

What do I need to stay healthy while on blood thinners?

  • Blood thinners can cause harm if not taken the right way and under the care of a doctor. Here are some things to keep in mind if you are taking blood thinners:
  • If you take blood thinners like warfarin, you will need to have regular blood tests at set times. These tests help your doctor see how much blood thinner you need to take. How much you need to take will depend on how thick or thin the medicine is making your blood. It will be important to keep your scheduled clinic visits for these tests. If you are taking aspirin or clopidogrel (but no warfarin), you will not need blood tests.
  • Be sure to take the medicine as directed and for as long as your doctor instructs.
  • Do not perform unsafe activities that could cause you to bleed or bruise.
  • Be sure to carry a medical ID card that will let others know you are on blood thinners in case you are in an accident.

Ask your doctor about what you should eat while taking blood thinners. Vitamin K can keep blood thinners from working as well as they should. Vitamin K is found in foods such as leafy greens, fish, spinach, brussel sprouts and liver. You should eat about the same amount of these foods each day while you take the blood thinner. 

What do I need to tell my doctor?

  • Tell your doctor about all the medicines you are taking right now, even over-the- counter drugs like vitamins, aspirin, or anti-inflammatory agents.
  • Talk to your doctor before you start taking a new medicine while on blood thinners, even over-the-counter drugs.
  • Tell all your health care workers that you are taking a blood thinner, even your dentist.
  • Talk to your doctor first before you stop taking your medicines, especially if you were given a blood thinner to prevent a blood clot after surgery or a stent procedure.
  • Always talk to your doctor about any side effects you feel while taking this medicine, particularly if you notice any bruising or bleeding.

Gill Heart Services

Coumadin Clinic: The UK Gill Heart Institute offers a clinic to watch over patients taking Coumadin/warfarin to make sure their international normalize ration (INR) levels stay in the proper range (most often between two and three). If the patient's level drops too low, there is a risk for clots, while if it rises too much, there is a risk for bleeding.

When you start taking Coumadin, it is very important for your doctor to watch you closely or for you take part in a clinic like the one at the Gill Heart Institute. Patients should be checked monthly and even more often when first starting on the medicine or with changes to diet, prescriptions or health problems. To enroll in the Gill Heart Institute Coumadin Clinic, you must be referred by your doctor. For an appointment, call 859-323-0295. 


UK Gill Heart Center
To schedule an appointment or find out more about heart-related diseases and blood thinners, call 1-800-333-8874 or 859-257-1000.

National Institutes of Health
Information about illnesses, blood thinners, tutorials and other resources.

American Heart Association
Offers information for heart-related diseases, medications, support groups and learning resources.

American Stroke Association
A division of the American Heart Association that provides information about stroke, prevention and medicines.

Page last updated: 8/7/2015 12:54:05 PM

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