Antiplatelet drugs: aspirin, P2Y12 inhibitors and GP IIb/IIIa antagonists
How aspirin, clopidogrel, prasugrel, ticagrelor, dipyridamole and the GP IIb/IIIa antagonists act on platelet activation, and how irreversibility, prodrug activation, CYP2C19 and adenosine explain their timing, interactions and side effects.
Tier 2Medical sciences concept
Written with AI assistance and fact-checked against the sources below. For exam study, not clinical decisions. How notes are made
At a glance
- Platelets adhere via GP Ib-von Willebrand factor, activate, then aggregate when GP IIb/IIIa binds fibrinogen. Thromboxane A2 (TXA2) and ADP amplify activation.
- Aspirin blocks TXA2 synthesis. P2Y12 inhibitors block the ADP receptor. GP IIb/IIIa antagonists block the final common pathway.
- Irreversible drugs (aspirin, clopidogrel, prasugrel) act for the platelet's life. Ticagrelor is reversible, so its offset follows its half-life.
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Sources
- Brieger D, Cullen L, Briffa T et al. National Heart Foundation of Australia and Cardiac Society of Australia and New Zealand: Australian clinical guideline for diagnosing and managing acute coronary syndromes 2025. Heart Lung Circ 2025;34(4):309-397AU/NZHeart, Lung and Circulation (NHFA/CSANZ), 2025
- Therapeutic Guidelines: Cardiovascular (antiplatelet drugs)AU/NZTherapeutic Guidelines Limited, 2026
- Australian Medicines HandbookAU/NZAustralian Medicines Handbook Pty Ltd, 2026
- PBS medicine status: prasugrel for acute coronary syndrome (listed 1 May 2025)AU/NZPharmaceutical Benefits Scheme, 2025
- Wallentin L, Becker RC, Budaj A et al. Ticagrelor versus clopidogrel in patients with acute coronary syndromes (PLATO). N Engl J Med 2009;361:1045-57New England Journal of Medicine, 2009
- Wiviott SD, Braunwald E, McCabe CH et al. Prasugrel versus clopidogrel in patients with acute coronary syndromes (TRITON-TIMI 38). N Engl J Med 2007;357:2001-15New England Journal of Medicine, 2007
- Lee CR, Luzum JA, Sangkuhl K et al. Clinical Pharmacogenetics Implementation Consortium guideline for CYP2C19 genotype and clopidogrel therapy: 2022 update. Clin Pharmacol Ther 2022;112:959-67Clinical Pharmacology & Therapeutics (CPIC), 2022
- Last updated
- 14 November 2026
What changed
- 14 November 2026 Personal emails, About story and Australian-style copy