Aspirin for prevention of blood clots

This leaflet is about the use of aspirin to reduce the risk of blood clots developing.

This leaflet has been written specifically about the use of this medicine in children. The information may differ from that provided by the manufacturer. Please read this leaflet carefully. Keep it somewhere safe so that you can read it again.

Your child should not take aspirin if they have ever had a reaction to aspirin or medicines known as non-steroidal anti-inflammatory drugs, used to treat inflammation.

Name of drug

Aspirin
Common brands: Angettes 75®, Caprin®, Nu-Seals® aspirin

Why is it important for my child to take this medicine?

Children who have heart or kidney problems may have an increased risk of blood clots. Blood clots can be dangerous if they form in the brain, lungs or heart. Taking aspirin regularly will help to reduce the risk of blood clots. (This is sometimes described as thinning the blood.)

Aspirin is also used after heart surgery and after organ transplants to reduce the risk of blood clots, and it may also be recommended for children who are at high risk of having a stroke.

You may have heard that aspirin should not be given to children because of the risk of a serious illness called Reye’s syndrome. However, for particular groups of children, the benefits of aspirin in reducing blood clotting far outweigh the risk of developing Reye’s syndrome. Ask your doctor if you are worried about this. More information is given below.

What is aspirin available as?

  • Dispersible tablets: 75 mg (white), 300 mg (white); these contain lactose
  • Enteric-coated tablets: 75 mg (white), 300 mg (white); these contain lactose

When should I give aspirin?

Aspirin is usually given once each day. This is usually in the morning.
Give the medicine at about the same time each day so that this becomes part of your child’s daily routine, which will help you to remember.

How much should I give?

Your doctor will work out the amount of aspirin (the dose) that is right for your child. The dose will be shown on the medicine label.

It is important that you follow your doctor’s instructions about how much to give.

How should I give aspirin?

Dispsersing a tabletDispersible tablets: disperse the tablet (or part tablet) in 5 mL of water (one medicine spoonful). Mix it vigorously – it will make a cloudy mixture. Draw up the right volume into an oral syringe. Your nurse or pharmacist will tell you how much of the mixture to give to your child. Pour any mixture left over down the sink. Do not keep it for another time.

Your doctor or pharmacist may have told you to break the tablet and disperse part of a tablet, to get the right dose.

Enteric-coated tablets should be swallowed whole with a glass of water, milk or juice. Your child should not chew the tablet.

When should the medicine start working?

The medicine should start working after about 3 days, although you will not see any difference in your child.

What if my child is sick (vomits)?

  • If your child is sick less than 30 minutes after having a dose of aspirin, give them the same dose again.
  • If your child is sick more than 30 minutes after having a dose of aspirin, you do not need to give them another dose. Wait until the next normal dose.

What if I forget to give it?

Give the dose as soon as you remember. If you have not remembered when your child goes to bed, do not give the missed dose. If you have missed more than one dose, contact your doctor for advice.

What if I give too much?

If you think you may have given your child too much aspirin, contact your doctor or NHS Direct (0845 4647 in England and Wales; 08454 24 24 24 in Scotland). Have the packet with you if you telephone for advice.

Are there any possible side-effects?

We use medicines to make our children better, but sometimes they have other effects that we don’t want (side-effects).

Side-effects you must do something about

If your child has black stools (poo), contact your doctor straight away or take your child to hospital, as they may have an ulcer.

If your child gets severe vomiting and has viral symptoms (fever [temperature above 38°C], aches and pains), contact your doctor straight away, in case they have Reye’s syndrome.

If your child gets a skin rash during the first 2 weeks of taking aspirin, contact your doctor, as they may be allergic to aspirin. Do not give any more doses of aspirin until your doctor tells you to.

Other side-effects you need to know about

If your child has asthma, they may get more attacks than usual. If this happens, contact your doctor for advice.

  • Your child may get stomach cramps and stomach pain when they first start taking aspirin. If this is still a problem after a week, contact your doctor. Giving each dose with some food may help.

Can other medicines be given at the same time as aspirin?

  • You can give your child medicines that contain paracetamol, unless your doctor has told you not to.
  • Do not give your child ibuprofen or other medicines called non-steroidal anti-inflammatory drugs, unless your doctor has said that you can.
  • Check with your doctor or pharmacist before giving any other medicines to your child. This includes herbal and complementary medicines.

Is there anything else I need to know about aspirin?

Your child should not take aspirin if they have ever had a reaction to aspirin or other medicines known as non-steroidal anti-inflammatory drugs, used to treat inflammation.

  • You may have heard that aspirin should not be given to children because of the risk of Reye’s syndrome. This is a very rare but dangerous disease that affects the brain and liver. Children affected have mostly been less than 5 years of age and have had a viral illness such as chicken pox. It has sometimes affected older children and teenagers.
  • For children at risk, the benefits of low-dose aspirin in reducing blood clots far outweigh the risk of your child developing Reye’s syndrome.

If your child develops viral symptoms (fever [temperature of 38°C or higher], aches and pains, headache) contact your doctor to discuss whether to stop or continue the aspirin. This is important, as the risk of Reye’s syndrome is more likely if your child has a viral illness.

  • Higher doses of aspirin are sometimes used in a rare illness called Kawasaki disease and for rheumatic fever.

General information about medicines

  • Try to give medicines at about the same time(s) each day, to help you remember.
  • Only give this medicine to your child. Never give it to anyone else, even if their condition appears to be the same, as this could do harm.
  • Make sure that you always have enough medicine. Order a new prescription at least 2 weeks before you will run out.
  • Make sure that the medicine you have at home has not reached the ‘best before’ or ‘use by’ date on the packaging. Give old medicines to your pharmacist to dispose of.

Where should I keep this medicine?

  • Keep the medicine in a cupboard, away from heat and direct sunlight. It does not need to be kept in the fridge.
  • Make sure that children cannot see or reach the medicine.
  • Keep the medicine in the container it came in.

Who to contact for more information

Your doctor, pharmacist or nurse will be able to give you more information about aspirin and about other medicines used to prevent blood clots.


You can also get useful information from:


Publication Date

17/11/2011

Copyright Disclaimer

Version 1.2, February 2011 (November 2011). © NPPG, RCPCH and WellChild 2011, all rights reserved. Reviewed by: February 2013.

The primary source for the information in this leaflet is the British National Formulary for Children. For details on any other sources used for this leaflet, please contact us through our website, www.medicinesforchildren.org.uk
We take great care to make sure that the information in this leaflet is correct and up-to-date. However, medicines can be used in different ways for different patients. It is important that you ask the advice of your doctor or pharmacist if you are not sure about something. This leaflet is about the use of these medicines in the UK, and may not apply to other countries. The Royal College of Paediatrics and Child Health (RCPCH), the Neonatal and Paediatric Pharmacists Group (NPPG), WellChild and the contributors and editors cannot be held responsible for the accuracy of information, omissions of information, or any actions that may be taken as a consequence of reading this leaflet.