Antiplatelet Medicine for Heart Attack and Unstable Angina

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Antiplatelet Medicine for Heart Attack and Unstable Angina


Generic NameBrand Name

How It Works

This medicine prevents the formation of blood clots.

Why It Is Used

Prevent a heart attack or stroke. Antiplatelet medicine is used to help lower the risk of a heart attack or stroke.

After a heart attack. Antiplatelet medicines might be used in the hospital after a heart attack to help blood to flow to the heart.

After angioplasty. If you had angioplasty and now have a stent, you will take antiplatelet medicines to help prevent another heart attack or a stroke. You will probably take aspirin plus another antiplatelet medicine. If you get a drug-eluting stent, you will probably take both of these medicines for at least one year. If you get a bare metal stent, you will take both medicines for at least one month but maybe up to one year. Then you will likely take daily aspirin long term. If you have a high risk of bleeding, your doctor may shorten the time you take these medicines.

How Well It Works

Antiplatelet medicine, taken with aspirin, helps lower the risk of a heart attack or stroke in people who have had angioplasty with a stent. This medicine lowers the risk that blood will clot in the stent and cause a heart attack.1

But for some people, clopidogrel does not work as well as it should, because their bodies may not break down the drug properly. Your doctor may do tests, such as a platelet test, to check on your blood clotting to make sure clopidogrel is working for you.1

Side Effects

All medicines have side effects. But many people don't feel the side effects, or they are able to deal with them. Ask your pharmacist about the side effects of each medicine you take. Side effects are also listed in the information that comes with your medicine.

Here are some important things to think about:

  • Usually the benefits of the medicine are more important than any minor side effects.
  • Side effects may go away after you take the medicine for a while.
  • If side effects still bother you and you wonder if you should keep taking the medicine, call your doctor. He or she may be able to lower your dose or change your medicine. Do not suddenly quit taking your medicine unless your doctor tells you to.

Call 911 or other emergency services right away if you have:

  • Trouble breathing.
  • Swelling of your face, lips, tongue, or throat.
  • Coughing up blood, vomiting blood, or passing black, tarry, or bloody stools. (These are signs of bleeding inside your body.)

Call your doctor right away if you have any unusual bleeding, such as:

  • Blood spots under your skin.
  • A nosebleed that you cannot stop.
  • Bleeding gums when you brush your teeth.

Call your doctor if you have:

  • Hives.

Other side effects of this medicine include:

  • Nausea.
  • Stomach pain or discomfort.

See Drug Reference for a full list of side effects. (Drug Reference is not available in all systems.)

What To Think About

Do not stop taking antiplatelet medicine without talking to your doctor. Make sure you take this medicine, especially if you have a stent. Antiplatelet medicine lowers the risk that blood will clot in the stent and cause a heart attack.

Before any surgery or medical or dental procedure, be sure your doctor or dentist knows that you take an antiplatelet. You might need to stop taking your medicine for a short time beforehand.

Be sure your doctors know all of the medicines that you take. This includes prescription medicine, over-the-counter medicine, vitamins, supplements, and herbal remedies.

For other tips on taking this medicine safely, see:

Click here to view an Actionset.Blood Thinners Other Than Warfarin: Taking Them Safely

Risk of bleeding

Antiplatelet medicine increases the risk of bleeding. This risk of bleeding is higher in some people. Your doctor will balance the benefits and risks of an antiplatelet based on your health. For example, you should not take prasugrel if you have had a stroke or transient ischemic attack (TIA), if you already have a bleeding problem, or if you need surgery very soon.

If you have a high risk of bleeding from taking an antiplatelet, your doctor may suggest you take a proton pump inhibitor or a histamine H2 acid reducer. This medicine may help prevent bleeding in your stomach. If you are taking both aspirin and an antiplatelet, talk with your doctor about how you can lower your risk of bleeding.

Testing for clopidogrel

Your doctor may do tests, such as a platelet test, to check on your blood clotting to make sure clopidogrel is working for you.1

A genetic test might be used to see if you have genes that let your body use clopidogrel. But experts aren't yet sure whether genetic changes keep clopidogrel from preventing a heart attack or stroke.

Taking medicine

Medicine is one of the many tools your doctor has to treat a health problem. Taking medicine as your doctor suggests will improve your health and may prevent future problems. If you don't take your medicines properly, you may be putting your health (and perhaps your life) at risk.

There are many reasons why people have trouble taking their medicine. But in most cases, there is something you can do. For suggestions on how to work around common problems, see the topic Taking Medicines as Prescribed.

Advice for women

If you are pregnant, breast-feeding, or trying to get pregnant, do not use any medicines unless your doctor tells you to. Some medicines can harm your baby. This includes prescription and over-the-counter medicines, vitamins, herbs, and supplements. And make sure that all your doctors know that you are pregnant, breast-feeding, or planning to get pregnant.


Follow-up care is a key part of your treatment and safety. Be sure to make and go to all appointments. And call your doctor if you are having problems. It's also a good idea to know your test results and keep a list of the medicines you take.

Complete the new medication information form (PDF)(What is a PDF document?) to help you understand this medication.



  1. Levine GN, et al. (2011). 2011 ACC/AHA/SCAI Guideline for percutaneous coronary intervention: A report of the American College of Cardiology Foundation/American Heart Association Task Force on Practice Guidelines and the Society for Cardiovascular Angiography and Interventions. Circulation, 124(23): e574–e651.


ByHealthwise Staff
Primary Medical ReviewerKathleen Romito, MD - Family Medicine
Primary Medical ReviewerE. Gregory Thompson, MD - Internal Medicine
Specialist Medical ReviewerStephen Fort, MD, MRCP, FRCPC - Interventional Cardiology
Last RevisedMay 14, 2012

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