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Antiplatelet — P2Y12 Inhibitor Pregnancy: B

Clopidogrel (Elderly)

Brand names: Plavix

Adult dose

Dose: 75 mg once daily
Route: oral
Frequency: once daily
Max: 75 mg/day (chronic); 300–600 mg loading for ACS
CYP2C19 polymorphism: poor metabolisers have reduced efficacy (up to 30% UK population); PPIs (especially omeprazole) reduce antiplatelet effect

Paediatric dose

Route:
Not routinely licensed in children; limited off-label use in congenital heart disease under cardiology guidance

Dose adjustments

Renal

No dose adjustment required; increased bleeding risk in renal impairment

Hepatic

Use with caution in hepatic impairment

Clinical pearls

  • CAPRIE trial: slightly superior to aspirin for secondary prevention of atherothrombotic events
  • CYP2C19 poor metabolisers (~2–14%): inadequate antiplatelet effect — consider prasugrel or ticagrelor
  • Omeprazole interaction: reduce antiplatelet effect via CYP2C19 competition — switch to pantoprazole

Contraindications

  • Active bleeding
  • Severe hepatic impairment

Side effects

  • Bleeding (GI, intracranial)
  • Bruising
  • Dyspepsia
  • Rash
  • TTP (rare)
  • Neutropenia (rare)

Interactions

  • Aspirin (combination increases bleeding — dual antiplatelet for ACS)
  • Omeprazole/esomeprazole (reduce antiplatelet effect — use pantoprazole if PPI required)
  • Warfarin/DOACs (increased bleeding)
  • NSAIDs

Monitoring

  • Signs of bleeding
  • FBC (TTP monitoring if unexplained neurological symptoms + low platelets)
  • Drug interactions review

Reference: BNFc; BNF 86; NICE NG185; CAPRIE trial. Verify against your local formulary and the latest BNF before prescribing.

Related

Curated clinical cross-links plus same-class fallbacks.

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