Antiplatelet (P2Y12 Inhibitor) Pregnancy: No clinical data on exposure during pregnancy; it is preferable not to use clopidogrel during pregnancy as a precautionary measure. Animal studies do not indicate direct or indirect harmful effects. Breast-feeding should not be continued during treatment. Clopidogrel was not shown to alter fertility in animal studies.

Clopidogrel (Stroke/TIA Secondary Prevention)

Brand names: Plavix

This page covers clopidogrel used for secondary prevention after ischaemic stroke or transient ischaemic attack, where it is an established oral antiplatelet option.

Auto-extracted from the source labelling — not yet independently clinician-verified. These values were distilled from the UK SPC (or the US label where noted) but have not had a clinician sign-off. Confirm against the current SmPC before prescribing.

Adult dose

Dose: Adults with moderate to high-risk TIA (ABCD2 score ≥4) or minor ischaemic stroke (NIHSS ≤3): a loading dose of clopidogrel 300 mg followed by clopidogrel 75 mg once daily, together with acetylsalicylic acid (ASA) 75 mg–100 mg once daily

Route: Oral — may be given with or without food

Frequency: 300 mg loading dose once, then 75 mg once daily. Treatment with clopidogrel and ASA should be started within 24 hours of the event and continued for 21 days, followed by single antiplatelet therapy

OTHER INDICATIONS IN THE SAME SPC (adults and elderly): general dosing is a single daily dose of 75 mg. Non-ST segment elevation ACS (unstable angina or non-Q-wave MI) — initiate with a single 300 mg or 600 mg loading dose (600 mg may be considered in patients <75 years when PCI is intended) and continue 75 mg once daily with ASA 75–325 mg daily, with ASA preferably not higher than 100 mg; clinical trial data support use up to 12 months with maximum benefit at 3 months. ST segment elevation MI — for medically treated patients eligible for thrombolytic/fibrinolytic therapy, 75 mg once daily initiated with a 300 mg loading dose in combination with ASA, with or without thrombolytics, started as early as possible and continued for at least four weeks; patients over 75 years should be initiated without a loading dose. When PCI is intended — 600 mg loading dose for primary PCI and for PCI more than 24 hours after fibrinolytic therapy (administer the 600 mg loading dose with caution in patients ≥75 years), or 300 mg loading dose for PCI within 24 hours of fibrinolytic therapy, then 75 mg once daily with ASA 75–100 mg daily for up to 12 months. Atrial fibrillation — 75 mg once daily with ASA 75–100 mg daily. The 600 mg loading dose is NOT recommended in non-ST segment elevation ACS in patients ≥75 years because of increased bleeding risk. MISSED DOSE: if less than 12 hours after the scheduled time, take the dose immediately and take the next dose at the regular time; if more than 12 hours, take the next dose at the regular time and do not double the dose. If a patient is to undergo elective surgery and antiplatelet effect is temporarily not desirable, discontinue 7 days prior to surgery. Triple antiplatelet therapy (clopidogrel + ASA + dipyridamole) for stroke secondary prevention is not recommended in acute non-cardioembolic ischaemic stroke or TIA because of increased haemorrhage risk. PAEDIATRIC: clopidogrel should not be used in children because of efficacy concerns. HEPATIC IMPAIRMENT: therapeutic experience is limited in patients with moderate hepatic disease who may have bleeding diatheses. Source: eMC SPC for Clopidogrel 75 mg film-coated tablets (§4.2).

Dose adjustments

Renal

Therapeutic experience is limited in patients with renal impairment; no numeric dose adjustment is stated in the SPC.

Dose auto-extracted from UK Summary of Product Characteristics (SPC) via the eMC; US FDA prescribing information (openFDA / DailyMed) — cross-check; US labelling may differ from UK — not yet clinician-verified. Always confirm against the product SmPC and your local formulary before prescribing.

Contraindications

Hypersensitivity to the active substance or to any of the excipients
Severe hepatic impairment
Active pathological bleeding such as peptic ulcer or intracranial haemorrhage

Side effects

Bleeding is the most common reaction, mostly reported during the first month of treatment; in CAPRIE the overall incidence of any bleeding was 9.3%, with severity similar to ASA
Increased major bleeding when combined with ASA (in ACTIVE-A major bleeding 6.7% with clopidogrel + ASA vs 4.3% with placebo + ASA), mainly extracranial and gastrointestinal
Intracranial bleeding — excess in the clopidogrel + ASA group compared with placebo + ASA (1.4% vs 0.8%)
Thrombotic thrombocytopenic purpura (TTP), reported very rarely, sometimes after short exposure — thrombocytopenia and microangiopathic haemolytic anaemia with neurological findings, renal dysfunction or fever; potentially fatal and requires prompt treatment including plasmapheresis
Acquired haemophilia has been reported
Haematological adverse reactions — prompt blood cell count and other appropriate testing whenever symptoms suggestive of bleeding arise

Interactions

ASA, heparin, glycoprotein IIb/IIIa inhibitors, NSAIDs including COX-2 inhibitors, SSRIs and other products associated with bleeding risk such as pentoxifylline — use with caution, increased bleeding risk (SPC §4.4)
Oral anticoagulants — concomitant administration is not recommended as it may increase the intensity of bleeding (SPC §4.4)
Triple antiplatelet therapy with ASA + dipyridamole for stroke secondary prevention — not recommended in acute non-cardioembolic ischaemic stroke or TIA due to increased haemorrhage risk (SPC §4.4; TARDIS showed more and more severe bleeding)
Strong CYP2C19 inducers (e.g. rifampicin) — increase active metabolite levels and platelet inhibition, potentially increasing bleeding risk; avoid concomitant use (SPC §4.4; US labelling §7.1)
CYP2C19 inhibitors — omeprazole and esomeprazole significantly reduce the antiplatelet activity of clopidogrel; avoid concomitant use (US labelling §5.1/§7.2)
Opioids — decreased exposure to clopidogrel; consider use of a parenteral antiplatelet agent (US labelling §7.3)
Full eMC §4.5 was not captured in the fetched source — verify the complete interaction section

Clinical monograph

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.

Reference: CAPRIE Trial (Lancet 1996); CHANCE Trial (Wang et al, NEJM 2013); NICE NG128; Drug verified in RxNorm (NLM); confirm dosing against the manufacturer SPC (eMC). Verify against your local formulary and current prescribing references before prescribing. The structured dose values shown have been reviewed by a clinician. Monograph status: clinician-reviewed (2026-07-04).

Curated clinical cross-links plus same-class fallbacks.

Calculators

Pathways