Cancard contains acetylsalicylic acid 81 mg — low-dose aspirin. At this strength it is not a painkiller. It thins the blood to prevent heart attack and stroke in people who have already had one, or who are at high cardiovascular risk. It is taken daily, long term.
What is Cancard?
Cancard contains acetylsalicylic acid 81 mg — aspirin, at what is usually called the low dose or cardio dose. The name reflects the cardiac purpose rather than any anti-cancer use.
81 mg is far below a pain-relieving amount. A headache dose of aspirin is 300 mg or more. At 81 mg the medicine is doing something quite different, and taking it for pain will not work.
The mechanism explains why. Aspirin blocks cyclo-oxygenase, and unlike other anti-inflammatories it does so irreversibly. In most cells that hardly matters — new enzyme appears within hours. In platelets it matters enormously, because platelets have no nucleus and cannot make replacement enzyme.
So a single low dose disables a platelet’s ability to clump for the rest of its life — about seven to ten days. Taken daily, it keeps a proportion of your platelets permanently inactivated, making the blood less likely to form the clots that cause heart attacks and strokes.
That is the whole point of the small dose: enough to affect platelets, little enough to spare the stomach as much as possible.
What is Cancard commonly used for?
Secondary prevention — in people who have already had a cardiovascular event, where the evidence is strongest:
- After a heart attack.
- After a stroke or transient ischaemic attack (TIA) caused by a clot.
- After a stent, angioplasty or bypass.
- Established angina and coronary artery disease.
- Peripheral arterial disease.
During a suspected heart attack — chewing a tablet while awaiting emergency help is standard advice and saves lives.
Primary prevention — in some people at high cardiovascular risk who have not yet had an event, on individual assessment.
The primary prevention question
This has genuinely changed, and it matters.
Routine daily aspirin for healthy adults who have never had a cardiovascular event is no longer generally recommended. Large trials showed the reduction in heart attacks was largely offset by an increase in serious bleeding, including in the gut and, less commonly, the brain. Guidelines have narrowed accordingly.
If you started taking a daily aspirin on your own initiative, or on advice from some years ago, it is worth asking your doctor whether it still makes sense for you.
If it was prescribed after a heart attack, stroke or stent, keep taking it. In secondary prevention the benefit is clear and substantial, and stopping abruptly is associated with an increased risk of a clotting event.
How Cancard fits into this medicine category
| Group | Examples | Purpose |
|---|---|---|
| Low-dose aspirin | Cancard, Ecotrin, Disprin CV | Antiplatelet; cardiovascular prevention |
| Other antiplatelets | Clopidogrel | Same purpose; used alone or with aspirin |
| Anticoagulants | Warfarin, rivaroxaban | Different clotting pathway; for AF, DVT |
| Statins | Aspavor, simvastatin | Lowers cholesterol; separate risk factor |
| Full-dose aspirin and NSAIDs | Aspirin 300 mg+, ibuprofen | Pain and inflammation |
See the pain, inflammation and musculoskeletal medicines hub.
What to check before using Cancard
Take it with or after food, at the same time each day, and swallow enteric-coated tablets whole.
Tell any doctor, dentist or surgeon that you take it before a procedure. The effect lasts about a week after the last tablet, and whether to pause it beforehand is their decision — do not stop preventive aspirin on your own.
Speak to a doctor or pharmacist if:
- You have a history of stomach ulcers or bleeding. Aspirin causes ulcers and bleeding even at 81 mg.
- You have a bleeding disorder, or take warfarin, clopidogrel or another anticoagulant.
- You have asthma. A recognisable subgroup of people with asthma react badly to aspirin.
- You have kidney or liver disease, or gout — aspirin can raise uric acid.
- You take an anti-inflammatory regularly. Ibuprofen in particular can block aspirin’s antiplatelet effect depending on timing, which defeats the purpose — ask a pharmacist about spacing, and note the same applies to naproxen.
- You take a corticosteroid or an SSRI antidepressant, both of which add to bleeding risk.
- You are pregnant. Low-dose aspirin is sometimes prescribed in pregnancy for specific reasons — never take it on your own initiative.
- The medicine is for anyone under 16, where aspirin is avoided because of Reye’s syndrome.
Follow the dispensing label. This page does not set doses.
Possible cautions and when to ask a pharmacist or doctor
Bleeding is the trade-off, and it is real. Aspirin causes stomach bleeding and increases bleeding elsewhere, including rarely in the brain. That is precisely why routine use in healthy people is no longer advised — and why, after a heart attack, the balance still clearly favours taking it. The calculation depends on your own risk.
Watch for bleeding signs: unusual bruising, bleeding gums, nosebleeds that are hard to stop, blood in the urine, black tarry stools, or vomiting blood or material like coffee grounds.
Some people are prescribed a stomach-protecting medicine alongside long-term aspirin, particularly with a previous ulcer or additional risk factors. Take it.
Do not stop suddenly in secondary prevention.
Enteric coating does not remove the risk. It reduces direct stomach irritation, but most of the ulcer risk comes from the systemic effect on prostaglandins, not from local contact.
Seek urgent medical attention for vomiting blood or coffee-ground material, black tarry stools, a sudden severe headache, one-sided weakness, slurred speech or visual loss, wheezing or difficulty breathing, facial or throat swelling, or ringing in the ears with hearing loss. For chest pain that might be a heart attack, call emergency services — and if advised, chew a tablet while waiting.
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Frequently asked questions
What is Cancard 81 mg used for? Preventing heart attack and stroke by thinning the blood. It is low-dose aspirin, taken daily and long term.
Can I take it for a headache? No. 81 mg is far below a pain-relieving dose. Pain relief needs 300 mg or more, which is a different product and purpose.
Should I take a daily aspirin to prevent a heart attack? Only if a doctor has advised it. Routine use in people who have never had a cardiovascular event is no longer generally recommended, because bleeding risk offsets the benefit.
Can I stop it before surgery or dental work? Tell the surgeon or dentist that you take it and let them decide. Do not stop preventive aspirin on your own.
Can I take ibuprofen with it? Ask a pharmacist. Ibuprofen can block aspirin’s antiplatelet effect depending on timing, and both together increase bleeding risk.
Does the enteric coating make it safe for my stomach? It reduces direct irritation but not the underlying ulcer risk, which comes from the systemic effect rather than local contact.