Aspirin is an oral medication that is taken for its antiplatelet effect, which reduces incidence of atherothrombotic events (e.g. myocardial infarction/acute coronary syndrome, ischaemic stroke and critical limb ischaemia secondary to peripheral arterial disease).

Maintenance dose or low-dose aspirin (typically 75mg OD) is sufficient to produce antiplatelet effects.

Aspirin is sometimes used as part of dual anti-antiplatelet therapy with an ADP receptor antagonist, like clopidogrel.

Higher doses (300-600mg) of aspirin are used in acute coronary syndrome and prior to percutaneous coronary intervention to increase platelet inhibition and help prevent a further atherothrombotic event.

When deciding whether to start a patient on any antithrombotic drug, ALWAYS weigh-up their risk of thrombosis vs. haemorrhagic risk.