Aspirin for prevention of blood clots

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Aspirin for prevention of blood clots

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

Information-Standard-logoThis leaflet has been written for parents and carers about how to use this medicine in children. Our information sometimes differs from that provided by the manufacturers, because their information is usually aimed at adult patients. 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 (acetylsalicylic acid)
Brand names: Caprin®, Micropirin®, 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, 300 mg
  • Enteric-coated tablets: 75 mg, 300 mg

These may contain lactose and aspartame.

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?

Dispersible-tabletsDispersible tablets: disperse the tablet in a small amount of water, your doctor or pharmacist will tell you how much to use. Mix it vigorously – it will make a cloudy mixture. Give the mixture to your child straight away. You can give it using a medicine spoon or oral syringe.

  • Occasionally, the only way to provide the correct dose of aspirin for your child will be to give part of a tablet or to disperse a tablet in a small amount of water and give some of the mixture. Your doctor or pharmacist will let you know if this is necessary and explain what to do.
  • This method should only be used when there is no other option and you have been told to do it. 
  • Any unused mixture should be poured into a paper towel and put in the bin. Do not pour it down the sink.

TabletsEnteric-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.

If your child is sick again, seek advice from your family doctor, pharmacist or hospital. They will decide what to do based on your child’s condition and the specific medicine involved.

What if I forget to give it?

If you remember before bedtime, give the missed dose. You do not need to wake up a sleeping child to give a 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 local NHS services (details at end of leaflet). 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 gets bad stomach pain, brings up (vomits) blood or their stools (poo) are very dark, contact your doctor or take your child to hospital straight away, 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.

There may, sometimes, be other side-effects that are not listed above. If you notice anything unusual and are concerned, contact your doctor. You can report any suspected side-effects to a UK safety scheme at http://www.mhra.gov.uk/yellowcard.

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, anti-coagulants (for example, warfarin), 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?

Aspirin is one of a group of drugs called non-steroidal anti-inflammatory drugs (NSAIDs). If your child has previously reacted to other drugs of this type, you should tell your doctor before starting aspirin.

  • 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. Contact your doctor to discuss whether to stop or continue the aspirin.
  • 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.
  • 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: 
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