Let’s Talk About Anticoagulants and Antiplatelet Agents

front page of the Let's Talk About Stroke: Anticoagulants and Antiplatelet Agents resourceAnticoagulants and antiplatelets are medicines that reduce blood clotting in an artery, vein or the heart. Doctors prescribe these to help prevent heart attacks and strokes caused by blood clots. Blood clots can block blood flow to your heart or your brain causing a heart attack or stroke.

Blood clots are made up of red blood cells, platelets, fibrin, and white blood cells. Anticoagulants and antiplatelets keep these parts from sticking together and forming a clot.

What should I know about anticoagulants?

Anticoagulants (sometimes known as “blood thinners”) are medicines that delay the clotting of blood. Examples are heparin, warfarin, dabigitran, apixaban, rivoraxaban and edoxaban.

Anticoagulants make it harder for blood clots to form in your heart, veins and arteries. They also can keep existing clots from growing larger. It’s important to follow these tips while on anticoagulants:

  • Take your medications exactly as prescribed.
  • If you take warfarin, have regular blood tests so your health care provider can tell how the medicine is working.
    • The test for people on warfarin is called a prothrombin time (PT) or International Normalized Ratio (INR) test.
  • Never take aspirin with anticoagulants unless your doctor tells you to.
  • Make sure all your health care providers know that you’re taking anticoagulants.
  • Always talk to your health care provider before taking any new medicines or supplements. This includes aspirin, vitamins, cold medicine, pain medicine, sleeping pills or antibiotics. These can affect the way anticoagulants work by strengthening or weakening them.
  • Discuss your diet with your health care providers. Foods rich in Vitamin K can reduce the effectiveness of warfarin. Vitamin K is in leafy, green vegetables, fish, liver, lentils, soybeans and some vegetable oils.
  • Tell your family that you take anticoagulant medicine.
  • Always carry your emergency medical ID card.

Could anticoagulants cause problems?

If you do as your doctor tells you, there probably won’t be problems. But you must tell them right away if:

  • You think you’re pregnant or you’re planning to get pregnant.
  • Your urine turns pink, red or brown. This could be a sign of urinary tract bleeding.
  • Your stools turn red, dark brown or black. This could be a sign of intestinal bleeding.
  • You bleed more than normal when you have your period.
  • Your gums bleed.
  • You have a very bad headache or stomach pain that doesn’t go away.
  • You get sick or feel weak, faint or dizzy.
  • You often find bruises or blood blisters.
  • You have an accident, such as a bump on the head, a cut that won’t stop bleeding or a fall of any kind.

What should I know about antiplatelet agents?

Antiplatelets keep blood clots from forming by keeping blood platelets from sticking together.

Almost everyone with coronary artery disease, including those who have had a heart attack, stent, or CABG, are treated with aspirin. Aspirin can help prevent an ischemic stroke. It can also help if you have had a TIA or if you have heart problems.

Many heart attack and stroke patients – and people seeking to avoid these events may get dual antiplatelet therapy (DAPT). With DAPT, two types of antiplatelets—aspirin and a P2Y12 inhibitor—are used to prevent blood clots.

P2Y12 inhibitors are usually prescribed for months or years along with aspirin therapy. You may be prescribed one of three of these medications: clopidogrel, prasugrel or ticagrelor. Prasugrel should not be prescribed if you have had a stroke or a transient ischemic attack (TIA). Your doctor will prescribe the best one for you based on your risk of blood clots and bleeding.

Do I need an emergency medical ID?

Yes, always keep it with you. It needs to include:

  • The name of the drugs you’re taking.
  • Your name, phone number and address.
  • The name, address and phone number of your doctor.


How can I learn more?

  1. Call 1-888-4-STROKE (1-888-478-7653) or visit stroke.org to learn more about stroke or find local support groups.
  2. Sign up for Stroke Connection, a free e-newsletter for stroke survivors and caregivers, at StrokeConnection.org.
  3. Connect with others who have also had an experience with stroke by joining our Support Network at stroke.org/SupportNetwork.

Do you have questions for your doctor or nurse?

Take a few minutes to write down your questions for the next time you see your health care provider. For example:

What kind of aspirin or other antiplatelet agent should I take?
What is the right dose for me?


We have many other fact sheets to help you make healthier choices, manage your condition or care for a loved one.
Visit stroke.org/LetsTalkAboutStroke to learn more


© Copyright 2020 American Heart Association, Inc., a 501(c)(3) not-for-profit. All rights reserved. American Stroke Association is a registered trademark of the AHA. Unauthorized use prohibited. DS16078 4/20