Blood Thinners

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Basics

• Summary
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• Diagnosis and Tests

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• Related Issues
• Specifics
• Genetics

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Research

• Statistics and Research
• Clinical Trials
• Journal Articles

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• Patient Handouts

Summary

Blood thinners are medicines that prevent blood clots from forming. They also keep existing blood clots from getting larger. Clots in your arteries, veins, and heart can cause heart attacks, strokes, and blockages. You may take 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

There are two main types of blood thinners. Anticoagulants such as heparin or warfarin (also called Coumadin) slow down your body's process of making clots. Antiplatelet drugs, such as aspirin, prevent blood cells called platelets from clumping together to form a clot.

When you take a blood thinner, follow 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 will probably 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.

Start Here

• Anti-Clotting Agents Explained (American Heart Association)
• Anticoagulants (Texas Heart Institute) Also in Spanish
• Anticoagulants and Drug-Food Interactions (National Jewish Health)
• Blood Thinner Pills: Your Guide to Using Them Safely (Agency for Healthcare Research and Quality) Also in Spanish
• What Are Anticoagulants and Antiplatelet Agents? (American Heart Association) - PDF
• What You Need to Know When Taking Anticoagulantion Medication (National Jewish Health) - PDF

Diagnosis and Tests

• Pharmacogenetic Tests (National Library of Medicine) Also in Spanish
• Therapeutic Drug Monitoring (National Library of Medicine) Also in Spanish

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) Also in Spanish
• Bridging Anticoagulation: Is it Needed When Warfarin Is Interrupted Around the Time of a Surgery or Procedure? (American Heart Association)
• Heparin-Induced Thrombocytopenia (American Heart Association) - PDF
• Medication Interactions: Food, Supplements and Other Drugs (American Heart Association)
• Prothrombin Time Test and INR (PT/INR) (National Library of Medicine) Also in Spanish
• Warfarin Side Effects: Watch for Interactions (Mayo Foundation for Medical Education and Research) Also in Spanish

Specifics

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

Genetics

• Genetics Home Reference: clopidogrel resistance (National Library of Medicine)
• Genetics Home Reference: warfarin resistance (National Library of Medicine)
• Genetics Home Reference: warfarin sensitivity (National Library of Medicine)

Statistics and Research

• Commonly Prescribed Blood Thinner Associated with Higher Risk of Post-Surgery Complications (National Institute of Arthritis and Musculoskeletal and Skin Diseases)
• Millions Taking Aspirin Without Clear Benefit (National Institutes of Health) Also in Spanish

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)

Journal Articles References and abstracts from MEDLINE/PubMed (National Library of Medicine)

• Article: Dosage of heparin for patency of the totally implanted central venous...
• Article: The Role of Anticoagulation in COVID-19-Induced Hypercoagulability.
• Article: Venous Thromboembolism in COVID-19: Towards an Ideal Approach to Thromboprophylaxis, Screening,...
• Blood Thinners -- see more articles

Find an Expert

• National Heart, Lung, and Blood Institute

Patient Handouts

• Aspirin and heart disease (Medical Encyclopedia) Also in Spanish
• Clopidogrel (Plavix) (Medical Encyclopedia) Also in Spanish
• How to give a heparin shot (Medical Encyclopedia) Also in Spanish
• Taking warfarin (Coumadin) (Medical Encyclopedia) Also in Spanish