Antiplatelets, aspirin, low dose


Aspirin is an antiplatelet medicine, which means it reduces the risk of clots forming in your blood.

Low-dose aspirin (usually 75mg a day) may be given to you if you have had:

  • a heart attack
  • a stroke
  • acute coronary syndrome (minor heart attack or unstable angina)
  • atrial fibrillation
  • a coronary artery bypass operation

It may also be given to you if you are considered to be at risk of having a heart attack or stroke. You may be considered to be at risk if you:

  • have high cholesterol
  • have high blood pressure
  • have diabetes
  • smoke

You may also be advised to take low-dose aspirin if you have diabetes and you:

  • have retinopathy (damage to the retina of the eye)
  • have nephropathy (kidney damage)
  • have had diabetes for more than 10 years
  • are over 50 years old
  • are taking medicines for high blood pressure

Treatment with an antiplatelet medicine such as aspirin is usually for life.

Higher doses of aspirin may be given for other conditions, but these pages focus on the use of low-dose aspirin.

Use in children

Aspirin may be given to children under specialist supervision after heart surgery, or to treat children with Kawasaki disease.

Aspirin must not be given to anyone under 16 years old, unless under specialist advice (see Aspirin - considerations for more information).

How it works

Antiplatelet medicines reduce the risk of clots forming in the blood. This reduces your risk of having a stroke or heart attack.

Normally, when there is a cut or break in a small blood vessel, a blood clot forms to plug the hole until the blood vessel heals.

Small cells in the blood called platelets make the blood clot. When a platelet detects a damaged area of a blood vessel, it produces a chemical that attracts other platelets and makes them stick together to form a blood clot.

Aspirin reduces the ability of the platelets to stick together and reduces the risk of clots forming.


A bypass is when the flow of blood or other fluid is redirected, permanently because of a blockage in the body, or temporarily during an operation.


Cholesterol is a fatty substance made by the body that lives in blood and tissue. It is used to make bile acid, hormones and vitamin D.

High blood pressure

Hypertension is when the pressure of the blood in your bloodstream is regularly above 140/90mmHG.


The retina is the nerve tissue lining the back of the eye, which senses light and colour and sends it to the brain as electrical impulses.

Last updated: 03 July 2012

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