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Antiplatelet / ACS

Clopidogrel (ACS / Post-PCI)

Brand names: Plavix

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

Clopidogrel is an oral antiplatelet (a P2Y12 inhibitor) used in acute coronary syndromes, after percutaneous coronary intervention, and for secondary prevention after ischaemic stroke or in peripheral arterial disease.

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

Acute coronary syndrome ( 2.1 ) – Initiate clopidogrel tablets with a single 300 mg oral loading dose and then continue at 75 mg once daily. – Initiating clopidogrel tablets without a loading dose will delay establishment of an antiplatelet effect by several days. Recent MI, recent stroke, or established peripheral arterial disease: 75 mg once daily orally without a loading dose. ( 2.2 ) 2.1 Acute Coronary Syndrome In patients who need an antiplatelet effect within hours, initiate clopidogrel tablets with a single 300 mg oral loading dose and then continue at 75 mg once daily. Initiating clopidogrel tablets without a loading dose will delay establishment of an antiplatelet effect by several …

Source: US FDA prescribing information (openFDA / DailyMed), label dated 2024-05-17. Accessed 2026-06-12. US dosing and indications can differ from UK practice — use UK sources for prescribing decisions.

Clinical monograph

How it works

Clopidogrel is a prodrug whose active metabolite irreversibly blocks the platelet P2Y12 ADP receptor, inhibiting platelet activation and aggregation for the platelet's lifespan.

Prescribing in practice

  • Often used with aspirin as dual antiplatelet therapy for a defined period after ACS/PCI, then continued as a single agent.
  • Stopping early after a coronary stent risks stent thrombosis — seek specialist advice before interrupting for surgery.
  • Activation depends on CYP2C19; effect is reduced in poor metabolisers and may be reduced by strong CYP2C19 inhibitors.
  • Bleeding risk is increased, especially with other antithrombotics or NSAIDs.

Monitoring

No routine monitoring of antiplatelet effect in standard practice; remain alert to bleeding.

Counselling the patient

  • Do not stop without advice, especially after a recent stent — stopping early can cause a clot.
  • Report bleeding or prolonged bruising.
  • Tell clinicians and dentists before procedures.

Evidence & guidelines

Dual antiplatelet therapy after ACS/PCI is guideline-directed; clopidogrel is also used for long-term secondary prevention where indicated.

Reference: CURE Trial (Yusuf et al. NEJM 2001); ESC NSTE-ACS 2020; ESC STEMI 2023; SPC Plavix; 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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