Clopidogrel (Stroke/TIA Secondary Prevention)

How it works

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

Prescribing in practice

• The principal hazard is bleeding, so assess bleeding risk and avoid unnecessary combination with other antiplatelets or anticoagulants beyond any defined short dual-therapy window.
• Proton pump inhibitors that strongly inhibit CYP2C19, particularly omeprazole and esomeprazole, may reduce its antiplatelet effect, so an alternative acid-suppressant is preferred if one is needed.
• As a prodrug requiring CYP2C19 activation, response may be reduced in poor metabolisers, a relevant consideration if recurrent events occur on treatment.

Monitoring

No routine platelet-function monitoring is required; review clinically for bleeding and recurrent vascular events at follow-up.

Counselling the patient

• Take once daily and do not stop without medical advice, as stopping increases stroke risk.
• Report unusual bruising, prolonged bleeding, black stools or blood in urine.
• Tell any dentist or surgeon you take an antiplatelet before procedures.

Evidence & guidelines

Long-term single-agent clopidogrel is recommended by NICE for secondary prevention after ischaemic stroke or TIA, with short-term dual antiplatelet therapy supported by trials such as POINT and CHANCE in the acute phase.