Intervention
Low-Dose Aspirin
Last updated Sun May 17 2026 00:00:00 GMT+0000 (Coordinated Universal Time)
What it is
Low-dose aspirin (75–100 mg/day) irreversibly acetylates COX-1, blocking platelet thromboxane A2 generation for the life of the platelet (~10 days). Used for decades in primary and secondary cardiovascular prevention.
What the modern evidence shows
- Secondary prevention (after a cardiovascular event): clear net benefit.
- Primary prevention in healthy older adults: ASPREE trial showed no reduction in cardiovascular events or dementia and an increase in major bleeding and all-cause mortality.
- Cancer: long-term aspirin reduces colorectal-cancer incidence and mortality (effect emerges after years); USPSTF formerly recommended low-dose aspirin for selected adults 50–59, then withdrew that recommendation in light of ASPREE.
- Pre-eclampsia prevention: clear benefit at 81–162 mg/day in selected pregnancies.
Practical implication
Routine low-dose aspirin for primary prevention in healthy adults is no longer recommended. The decision in individuals with intermediate cardiovascular risk requires careful discussion of bleeding risk.
Safety
- Major bleeding (gastrointestinal, intracranial).
- Allergy / aspirin-sensitive asthma.
- Reye syndrome in children (do not use for febrile illness in under-19s).
Related entries
References
- McNeil, J. J. et al. Effect of aspirin on all-cause mortality in the healthy elderly (ASPREE). N. Engl. J. Med. 379, 1519–1528 (2018).