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Antiplatelet / ACS

Aspirin (Antiplatelet — ACS/PCI)

Brand names: Disprin, Caprin

Used in: Acute Coronary Syndrome & Chest Pain Stroke & TIA

Low-dose aspirin is an antiplatelet used in acute coronary syndromes and for long-term secondary prevention of cardiovascular events; it is not used for routine primary prevention because the bleeding risk usually outweighs benefit.

Dosing — being independently re-sourced

ClinCalc Pro is rebuilding its dose data from primary open sources — the manufacturer SmPC (eMC), the WHO Model Formulary and other official references — under clinician review. This drug's structured dose is not yet published here. Confirm all doses against the product SmPC and your local formulary before prescribing.

US labelling (FDA)

Reference — US labelling, may differ from UK

Directions drink a full glass of water with each dose adults and children 12 years and over: take 4 to 8 tablets every 4 hours not to exceed 48 tablets in 24 hours unless directed by a doctor children under 12 years: consult a doctor

Source: US FDA prescribing information (openFDA / DailyMed), label dated 2024-04-16. Accessed 2026-06-12. US dosing and indications can differ from UK practice — use UK sources for prescribing decisions.

Clinical monograph

How it works

Aspirin irreversibly acetylates cyclo-oxygenase-1 in platelets, blocking thromboxane A2 production and platelet aggregation for the platelet's lifespan.

Prescribing in practice

  • A higher loading dose is given in ACS, followed by a low maintenance dose.
  • Gastrointestinal bleeding risk rises with age and with other antithrombotics, NSAIDs or steroids; consider gastroprotection in higher-risk patients.
  • Avoid in active peptic ulceration and in children (Reye's syndrome risk), and use caution in aspirin-sensitive asthma.

Monitoring

No routine monitoring; review for dyspepsia or bleeding, particularly in older patients and with co-prescribed antithrombotics.

Counselling the patient

  • Take it with or after food.
  • Report black stools, vomiting blood, or persistent indigestion.
  • Do not stop suddenly after a cardiac event without advice.

Evidence & guidelines

Aspirin is standard in ACS and long-term secondary prevention; routine primary-prevention use is no longer recommended for most people.

Reference: ESC STEMI Guidelines 2023; ESC NSTE-ACS Guidelines 2020; NICE NG185 (ACS); SPC Aspirin; Drug verified in RxNorm (NLM); confirm dosing against the manufacturer SPC (eMC). Verify against your local formulary and current prescribing references before prescribing. Monograph status: clinician-reviewed (2026-07-04).

Related

Curated clinical cross-links plus same-class fallbacks.

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