Daily low-dose aspirin is a blood thinning medicine also known as acetylsalicylic acid.
Low-dose aspirin comes as tablets and is only available on prescription.
It's also known by the brand names Caprin, Nuprin and Nu-seals.
Uses of low-dose aspirin
Low-dose aspirin helps to prevent heart attacks and strokes if you’re at high risk of them.
Taking low-dose aspirin to prevent heart attacks and strokes is not the same as taking aspirin as a painkiller.
Only take daily low-dose aspirin if your GP prescribes it.
Get emergency help
You might need emergency help if you have a serious allergic reaction (anaphylaxis) or serious side effect.
Serious allergic reaction
A serious allergic reaction to aspirin is rare.
Emergency action required: Call 999 or go to an emergency department if:
- you get a skin rash that may include itchy, red, swollen, blistered or peeling skin
- you're wheezing
- you get tightness in the chest or throat
- you have trouble breathing or talking
- your mouth, face, lips, tongue or throat start swelling
These are warning signs of a serious allergic reaction. You might need to go to hospital.
Serious side effects
Serious side effects are rare.
Urgent advice: Call your GP straight away if you get:
- red, blistered and peeling skin
- coughing up blood or blood in your pee, poo or vomit
- yellow skin or the whites of your eyes turn yellow - this can be a sign of liver problems
- painful joints in the hands and feet - this can be a sign of high levels of uric acid in the blood
- swollen hands or feet - this can be a sign of water retention
When you start taking low-dose aspirin
You may not notice any difference in how you feel after you start taking low-dose aspirin. This does not mean that the medicine is not working.
Carry on taking daily low-dose aspirin even if you feel well, as you'll still be getting the benefits.
Take low-dose aspirin with food so it does not upset your stomach.
You can drink alcohol while taking low-dose aspirin.
Do not drink more than the recommended daily intake of 17 units of alcohol per week for men and 11 units of alcohol per week for women, as it might irritate your stomach.
Check if you can take low-dose aspirin
You can take low-dose aspirin if your GP prescribes it.
It's sometimes called baby aspirin because of the small dose, but it's not safe for children.
Never give aspirin to a child younger than 16, unless their GP prescribes it. Aspirin can be associated with Reye's syndrome in children.
Check with your GP before starting to take low-dose aspirin if you:
- already have a medical condition
- have had an allergic reaction to medicine in the past
- have heavy periods
- are pregnant or trying to get pregnant
- are breastfeeding
- have a history of stomach ulcers or gastrointestinal bleeding after taking certain medicines, including aspirin or ibuprofen
- have any blood clotting disorder such as haemophilia
If you are pregnant, think you might be pregnant or are trying to get pregnant, talk to your GP or pharmacist before taking aspirin.
You should not take aspirin while pregnant unless your GP has told you to.
Your GP may advise you take it during pregnancy:
- to help prevent heart attack and stroke
- to help prevent pre-eclampsia (pregnancy-related high blood pressure)
- if you're having fertility treatment
- if you have had several previous miscarriages
Low-dose aspirin is not approved for these uses. But your GP may decide to use it if they think the potential benefits to your health outweigh the risks. This is called 'off-label use'. Talk to your GP or pharmacist about off-label use.
If you are breastfeeding, talk to your GP or pharmacist before taking aspirin.
Aspirin is not recommended while you're breastfeeding.
But your GP may suggest that you take low-dose aspirin while you're breastfeeding if they think the benefits of the medicine outweigh the possible harm.
How and when to take low-dose aspirin
Always take low-dose aspirin exactly as your GP has advised.
You'll usually take low-dose aspirin once a day. Most people will need to take it for the rest of their life.
Do not take it on an empty stomach. It's best to take it with or just after food. This will make it less likely to upset your stomach.
Low-dose aspirin tablets have a special coating that means they may be gentler on your stomach. Do not chew or crush them because it'll stop the coating working.
If you also take indigestion remedies, take them at least 2 hours before or after you take your aspirin. The antacid in the indigestion remedy affects the way the coating on these tablets works.
If you forget to take it
Do not take a double dose to make up for a forgotten dose.
If you forget to take a dose of aspirin, take it as soon as you remember. If you do not remember until the following day, skip the missed dose.
If you take too much
Taking one or 2 extra tablets by accident is unlikely to be harmful.
Urgent advice: Call your GP straight away if you take too much aspirin by accident and experience side effects such as:
- feeling sick (nausea)
- ringing in the ears (tinnitus)
- hearing problems
- fast breathing
- high temperature of 38 degrees Celsius or higher (fever)
If you need to go to emergency department (ED), do not drive yourself - get someone else to drive you or call 999 or 112 for an ambulance.
Take the aspirin packet or leaflet inside it, plus any remaining medicine with you.
Talk to your GP, a pharmacist or nurse if side effects bother you or do not go away
Side effects include:
- mild indigestion
- feeling or being sick
- loss of appetite
- bleeding more easily than normal - because aspirin thins your blood, it can sometimes make you bleed or bruise more easily, and the bleeding may take longer to stop
Read the patient information leaflet that comes with your medicine for a full list of side effects.
Find your patient information leaflet
Your patient information leaflet is the leaflet that comes with your medicine. You can find a digital version of the leaflet online.
Report side effects
You can report any suspected side effects to the the Health Products Regulatory Authority (HPRA): report an issue - hrpa.ie
Taking low-dose aspirin with other medicines
Some medicines interfere with the way low-dose aspirin works.
If you’re on any other medicines or supplements, check with your GP, a pharmacist or nurse before you start taking low-dose aspirin.
It's safe to take paracetamol with low-dose aspirin.
Do not take ibuprofen at the same time as low-dose aspirin without talking to your GP.
Aspirin and ibuprofen both belong to the same group of medicines called non-steroidal anti-inflammatory drugs (NSAIDs).
Taking them together can increase your chances of side effects like stomach irritation.
This content was fact checked by a pharmacist, a GP, the National Medication Safety Programme (Safermeds) and the Health Products Regulatory Authority (HPRA).