Antiplatelet Therapy

Antiplatelets are a group of medicines that stop blood cells (called platelets) from sticking together and forming a blood clot. Antiplatelet medicines can stop blood clots from forming.

What is antiplatelet therapy?

Antiplatelets are a group of medicines that stop blood cells (called platelets) from sticking together and forming a blood clot.

Whenever there is an injury in your body, platelets are sent to the site of the injury, where they clump together to form a blood clot. This stops the bleeding in your body. If you have a cut or a wound, this is a good thing. But, sometimes, platelets will clump together inside a blood vessel that is injured, swollen (inflamed), or that has plaque build-up (atherosclerosis). When this happens, the platelets can cause a blood clot to form inside the vessel. Platelets can also cause blood clots to form around stents, artificial heart valves, and other devices that are placed inside the heart or blood vessels. Antiplatelet medicines can stop blood clots from forming.

Why do I need antiplatelet therapy?

Patients are usually given antiplatelets if they have a history of

Antiplatelets may also be given to patients during and after angioplasty and stent procedures and after coronary artery bypass surgery. Some patients with atrial fibrillation or valve disease also take antiplatelets.

Are there different types of antiplatelet medicines?

There are many different types of antiplatelet medicines. Even though each type works in a different way, all antiplatelet medicines help to keep platelets from sticking together and forming blood clots.

  • Aspirin is the most common type of antiplatelet medicine. Some patients who are recovering from a heart attack are given aspirin to prevent further blood clots from forming in the coronary arteries. Low-dose aspirin (sometimes called “baby aspirin”) may prevent heart attacks and strokes in people who take it every day.
  • Adenosine diphosphate (ADP) receptor inhibitors are usually given to patients who have had a recent heart attack or stroke, because these patients have a greater risk of having another heart attack or stroke. Doctors may also give this medicine to patients with mitral valve disease or those who have had heart valve replacement. Some patients with peripheral vascular disease (PVD) may also be good candidates for ADP receptor inhibitors, because poor blood circulation in the legs can lead to blood clots.
  • Adenosine reuptake inhibitors are usually given to patients in combination with an anticoagulant. Patients may also take this type of antiplatelet therapy in combination with aspirin if they have a heart condition that increases their risk of blood clots.
  • Glycoprotein IIB/IIIA inhibitors are given by an intravenous (IV) needle directly into the bloodstream, so patients must be in the hospital to receive them. Patients usually receive this type of antiplatelet medicine to prevent blood clots that sometimes form during angioplasty and stent procedures. They are also used in patients with angina who are going to have an angioplasty or stent procedure.
  • Phosphodiesterase inhibitors is most often used in patients with PVD to reduce leg pain that comes with walking (called intermittent claudication). Patients with PVD have a greater risk of developing blood clots in their legs, so some PVD patients need to take antiplatelet medicines. Patients with heart failure should not take this type of antiplatelet medicine, because studies have shown it can lead to death.

How much do I take?

Because there are so many different kinds and strengths of antiplatelet therapy, the amount you should take may vary. Most types of antiplatelet medicines come in a pill form, but some types can only be given to you by IV in the hospital. Talk to your doctor or pharmacist for more information about how and when to take antiplatelet medicines.

What if I am taking other medicines?

Other medicines that you may be taking can increase or decrease the effect of antiplatelets. These effects are called an interaction. Be sure to tell your doctor about every medicine and vitamin or herbal supplement that you are taking, so he or she can make you aware of any interactions.

The following are categories of medicines that can increase or decrease the effects of antiplatelet medicines. Because there are so many kinds of medicines within each category, not every type of medicine is listed by name. Tell your doctor about every medicine that you are taking, even if it is not listed below.

  • Over-the-counter or prescription medicines that contain aspirin
  • Nonsteroidal anti-inflammatory drugs (NSAIDs), such as ibuprofen and naproxen
  • Over-the-counter cough and cold medicines
  • Medicines to prevent seizures
  • Proton-pump inhibitors (PPIs)
  • Medicines for heartburn and reducing stomach acid and acid reflux
  • Tamoxifen
  • Certain medicines for diabetes
  • Certain diuretic medicines (“water pills”)

While taking antiplatelets, you should also avoid smoking and drinking alcohol. Also, tell your doctor or dentist that you are taking antiplatelet medicines before you have any kind of surgical or dental procedure. Because antiplatelets reduce the blood’s ability to clot, taking them before surgical or dental procedures can lead to excess bleeding. You might need to stop taking this medicine for 5 to 7 days before your dental work or surgery, but do not stop taking this medicine without talking to your doctor first.

What else should I tell my doctor?

Talk to your doctor about your medical history before you start taking antiplatelet therapy regularly. The risks of taking the medicine need to be weighed against its benefits. Here are some things to consider if you and your doctor are deciding whether you should begin antiplatelet therapy

  • You have an allergy to antiplatelet medicines, ibuprofen, or naproxen.
  • You are thinking of becoming pregnant, you are pregnant, or you are breast-feeding your baby.
  • You have hemophilia.
  • You have Hodgkin’s disease.
  • You have a stomach ulcer, a bleeding ulcer, or other stomach problems.
  • You have kidney or liver disease.
  • You have coronary artery disease or congestive heart failure.
  • You have high blood pressure.
  • You have asthma.
  • You have gout.
  • You are or ever have been anemic (low red blood cell count in the blood).
  • You have nasal polyps.
  • You take part in sports or other activities that put you at risk for bleeding or bruising.

What are the side effects?

Sometimes a medicine causes unwanted effects. These are called side effects. Not all of the side effects for antiplatelet therapy are listed here. If you feel these or any other effects, you should check with your doctor.

Common side effects:

  • Extreme tiredness (fatigue)
  • Heartburn
  • Headache
  • Upset stomach and nausea
  • Stomach pain
  • Diarrhea
  • Nosebleed

Rare side effects:

  • Allergic reaction, with swelling of the face, throat, tongue, lips, hands, feet, or ankles
  • Skin rash, itching, or hives
  • Throwing up, especially if the vomit has blood in it or looks like coffee grounds
  • Dark or bloody stools or blood in the urine
  • Trouble breathing or swallowing
  • Trouble speaking or slowed speech
  • Unusual bleeding or bruising
  • Fever, chills, or sore throat
  • Fast heartbeat (arrhythmia)
  • Yellowing of your skin or eyes (jaundice)
  • Joint pain
  • Weakness or numbness of your arm or leg
  • Confusion or hallucinations

Again, tell your doctor right away if you have any of these side effects. Do not stop taking your medicine unless your doctor tells you to. If you stop taking your medicine without checking with your doctor, it can make your condition worse.

You may need to take antiplatelet medicines for the rest of your life, depending on your condition. You will need to have your blood tested regularly to see how your blood is clotting. Keep all your appointments with your doctor and the lab, so that your body’s response to antiplatelet therapy can be closely monitored.

You should wear a medical alert bracelet or carry a card in your wallet or purse, so that in the event of an accident, emergency responders will know that you are taking antiplatelet medicines.



The information in this Medicines for Cardiovascular Disease section has been taken from a number of sources. It is meant to give you information about certain medicines, but it does not cover all of the possible uses, warnings, side effects, or interactions with other medicines and vitamin or herbal supplements. This information should not be used as medical advice for individual problems. Please talk to your doctor and/or your pharmacist for prescription instructions.