Aspirin

Aspirin has two very different uses

Aspirin (acetylsalicylic acid) is one of the oldest and most widely used medicines. At standard doses it relieves pain and reduces fever. At low daily doses (75mg) it prevents blood clots — protecting against heart attack and stroke in people at high risk. These uses require different doses and medical guidance.

Pain and fever relief

Standard 300mg aspirin tablets used for:

• headache and migraine
• period pain
• toothache
• muscle and joint aches
• fever

Typical dose: 300mg to 600mg every 4 to 6 hours as needed. Maximum 4g (12 x 300mg tablets) in 24 hours unless advised otherwise. Take with or after food to protect the stomach.

Also available as dispersible tablets — dissolve in water before drinking.

Low-dose aspirin for heart and stroke prevention

75mg daily low-dose aspirin makes blood platelets less sticky, reducing clot formation. Used long-term in people who have had:

• heart attack
• stroke or TIA (mini-stroke)
• angioplasty or stent insertion
• certain heart conditions at high clot risk

Do not start low-dose aspirin for prevention without GP advice. The balance of benefit versus bleeding risk depends on your individual cardiovascular risk, age, and medical history. For people who have never had a heart event, aspirin is not routinely recommended for primary prevention.

Aspirin during a suspected heart attack

If you suspect a heart attack, call 999 first. The call handler may advise chewing one 300mg aspirin tablet while waiting for the ambulance — if you are not allergic to aspirin and have not been told to avoid it.

Chewing (not swallowing whole) allows faster absorption. Do not delay calling 999 to find aspirin.

Side effects and risks

Common:

• stomach irritation, indigestion, nausea
• increased bleeding tendency — nosebleeds, bruising

Serious (seek urgent help):

• stomach or gut bleeding — black tarry stools, vomiting blood
• allergic reaction — wheezing, swelling, rash
• Reye’s syndrome in children — never give aspirin under 16

Who should avoid or use cautiously:

• history of stomach ulcers or GI bleeding
• bleeding disorders
• asthma triggered by aspirin/NSAIDs
• severe kidney or liver disease
• pregnancy (especially third trimester) — paracetamol preferred
• children and teenagers under 16

Aspirin vs ibuprofen and paracetamol

Paracetamol — gentler on the stomach; first choice for many people including pregnancy.

Ibuprofen — anti-inflammatory; do not take with aspirin without advice — combined NSAID use increases bleeding risk.

Aspirin — anti-inflammatory and antiplatelet; unique role in cardiovascular prevention at low doses.

A pharmacist helps choose the right option for your situation.

Taking aspirin safely

• take with food if it upsets your stomach
• tell doctors and dentists you take aspirin — including before surgery
• inform them before any anticoagulant (warfarin, apixaban) is started
• stop only on medical advice — sudden stopping after long-term use may increase clot risk

Enteric-coated aspirin

Some low-dose aspirin has a gastro-resistant coating to reduce stomach irritation. It still carries bleeding risk — the coating does not eliminate it entirely.

Aspirin and other medicines

Aspirin interacts with:

• warfarin and other anticoagulants — increased bleeding
• other NSAIDs — ibuprofen, naproxen
• SSRIs — some antidepressants increase bleeding risk
• methotrexate — aspirin affects clearance

Tell your GP and pharmacist about all medicines you take.

When to see a GP

• before starting daily low-dose aspirin for heart protection
• if you have stomach pain, black stools, or vomiting blood while taking aspirin
• if you need pain relief regularly — underlying causes should be assessed

Children and aspirin

Never give aspirin to children under 16, especially during viral illnesses (chickenpox, flu). Use paracetamol or ibuprofen (age-appropriate) instead.

Common questions

What is aspirin used for?

Pain relief (headache, toothache, period pain), reducing fever, and at low daily doses (75mg) preventing blood clots in people who have had a heart attack, stroke, or TIA. It is also used briefly after some heart procedures and in certain arthritis conditions.

What dose of aspirin should I take for pain?

Standard tablets are 300mg — one to two tablets every 4 to 6 hours, maximum 12 tablets in 24 hours. Follow the packet. Low-dose 75mg tablets are for clot prevention, not pain — do not use them interchangeably without medical advice.

Should I take aspirin to prevent a heart attack?

Only if prescribed or recommended by a GP after assessing your individual risk. Low-dose aspirin prevents clots but increases bleeding risk — the balance favours aspirin in people who have already had a heart attack or stroke, but is less clear for people who have never had one.

Can I take aspirin with other painkillers?

Do not take aspirin with ibuprofen or other NSAIDs without advice — combined use increases stomach bleeding risk. Paracetamol can usually be taken alongside aspirin if needed. Check with a pharmacist.

Why should children not take aspirin?

Aspirin in children and teenagers (under 16) is linked to Reye's syndrome — a rare but serious liver and brain condition, especially after viral infections. Use paracetamol or ibuprofen for children instead.

Sources

• NHS — Aspirin for pain relief
• NHS — Low-dose aspirin