Blood Thinners

Summary

What are blood thinners?

Blood thinners are medicines that prevent blood clots from forming. They do not break up clots that you already have. But they can stop those clots from getting bigger. It’s important to treat blood clots, because clots in your blood vessels and heart can cause heart attacks, strokes, and blockages.

Who needs blood thinners?

You may need a blood thinner if you have:

• Certain heart or blood vessel diseases
• An abnormal heart rhythm called atrial fibrillation
• A heart valve replacement
• A risk of blood clots after surgery
• Congenital heart defects

What are the different types of blood thinners?

There are different types of blood thinners:

• Anticoagulants, such as heparin or warfarin (also called Coumadin), slow down your body’s process of making clots.
• Antiplatelets, such as aspirin and clopidogrel, prevent blood cells called platelets from clumping together to form a clot. Antiplatelets are mainly taken by people who have had a heart attack or stroke.

How can I take blood thinners safely?

When you take a blood thinner, follow the directions carefully. Blood thinners may interact with certain foods, medicines, vitamins, and alcohol. Make sure that your health care provider knows all of the medicines and supplements you are using.

You may need regular blood tests to check how well your blood is clotting. It is important to make sure that you’re taking enough medicine to prevent clots, but not so much that it causes bleeding.

What are the side effects of blood thinners?

Bleeding is the most common side effect of blood thinners. They can also cause an upset stomach, nausea, and diarrhea.

Other possible side effects can depend on which type of blood thinner that you are taking.

Call your provider if you have any sign of serious bleeding, such as:

• Menstrual bleeding that is much heavier than normal
• Red or brown urine
• Bowel movements that are red or black
• Bleeding from the gums or nose that does not stop quickly
• Vomit that is brown or bright red
• Coughing up something red
• Severe pain, such as a headache or stomachache
• Unusual bruising
• A cut that does not stop bleeding
• A serious fall or bump on the head
• Dizziness or weakness

Start Here

• Anticoagulants Texas Heart Institute
• Anticoagulants and Drug-Food Interactions National Jewish Health
• Blood Thinner Pills: Your Guide to Using Them Safely Agency for Healthcare Research and Quality
• What Are Anticoagulants and Antiplatelet Agents? American Heart Association

Specifics

• Anticoagulation (Blood Thinners) and Congenital Heart Defects American Heart Association
• Antiplatelet Therapy Texas Heart Institute
• Daily Aspirin Therapy: Understand the Benefits and Risks Mayo Foundation for Medical Education and Research
• Patient’s Guide to Taking Warfarin American Heart Association

Patient Handouts

• Antiplatelet drugs – P2Y12 inhibitors Medical Encyclopedia
• Aspirin and heart disease Medical Encyclopedia
• How to give a heparin shot Medical Encyclopedia
• Taking warfarin (Coumadin) Medical Encyclopedia

Related Issues

• Blood Thinners and Dental Care American Academy of Oral Medicine
• Blood Thinners: Can I Still Get Blood Clots? Mayo Foundation for Medical Education and Research
• Medication Interactions: Food, Supplements, and Other Drugs American Heart Association
• Prothrombin Time Test and INR (PT/INR) National Library of Medicine
• Warfarin Side Effects: Watch for Interactions Mayo Foundation for Medical Education and Research

Clinical Trials

• ClinicalTrials.gov: Anticoagulants National Institutes of Health
• ClinicalTrials.gov: Heparin National Institutes of Health
• ClinicalTrials.gov: Platelet Aggregation Inhibitors National Institutes of Health
• ClinicalTrials.gov: Warfarin National Institutes of Health

Genetics

• Clopidogrel resistance: MedlinePlus Genetics National Library of Medicine
• Warfarin sensitivity: MedlinePlus Genetics National Library of Medicine

Find an Expert

• National Heart, Lung, and Blood Institute National Heart, Lung, and Blood Institute

Diagnosis and Tests

• Pharmacogenetic Tests National Library of Medicine
• Therapeutic Drug Monitoring National Library of Medicine

Journal Articles

• Blood Thinners

Encyclopedia

• Taking warfarin (Coumadin, Jantoven) – what to ask your doctor Medical Encyclopedia