What is the recommended dosage and administration instructions for Clopidogrel (Plavix) 75mg?

Clopidogrel 75mg Dosage and Administration

For maintenance therapy after acute coronary syndrome or stent placement, administer clopidogrel 75 mg once daily orally, continuing for at least 12 months in patients who are not at high risk of bleeding. 1

Loading Dose Recommendations

The loading dose varies significantly based on clinical context:

• For STEMI undergoing primary PCI: Administer 600 mg loading dose as early as possible or at the time of PCI for more rapid and potent platelet inhibition compared to 300 mg 1

• For STEMI with fibrinolytic therapy:

  • Age ≤75 years: 300 mg loading dose 2
  • Age >75 years: No loading dose, start with 75 mg daily 2

• For elective PCI in stable CAD:

  • 600 mg at least 2 hours before procedure, OR
  • 300 mg at least 6 hours before procedure (best established evidence when time permits) 2, 3

• For patients already on 75 mg maintenance dose requiring reloading: A 900 mg loading dose provides significantly better platelet inhibition than 300 or 600 mg, reducing suboptimal response rates from 23.6% (300 mg) to 5.3% (900 mg) 4

Maintenance Therapy Duration

Duration depends on stent type and bleeding risk:

• Bare-metal stent: At least 1 month (minimum 2 weeks if high bleeding risk), ideally up to 12 months 2, 1

• Drug-eluting stent (sirolimus): At least 3 months, ideally up to 12 months 2

• Drug-eluting stent (paclitaxel): At least 6 months, ideally up to 12 months 2

• After brachytherapy: Continue indefinitely 2

Concomitant Aspirin Therapy

Dual antiplatelet therapy is essential:

• Loading: Aspirin 162-325 mg immediately before PCI 2, 1
• Maintenance: Aspirin 81 mg daily (preferred dose) indefinitely 2, 1

Administration Instructions

• Timing: Take once daily at the same time each day for consistent drug levels 3
• Food: Can be taken with or without food, as absorption is unaffected 5
• Missed dose: If a dose is missed, take the next scheduled dose (do not double up) 6

Critical Warnings and Contraindications

Absolute contraindications include:

• Active pathological bleeding (peptic ulcer, intracranial hemorrhage) 6
• Hypersensitivity to clopidogrel or any component 6

Important drug interactions to avoid:

• Omeprazole and esomeprazole: Significantly reduce clopidogrel's active metabolite; avoid concomitant use 6
• Opioids: Decrease clopidogrel exposure; consider parenteral antiplatelet agents in acute settings 6

CYP2C19 poor metabolizers: Patients with two loss-of-function alleles have diminished antiplatelet effect and higher rates of adverse cardiac events; consider alternative P2Y12 inhibitors (prasugrel or ticagrelor) 6

Surgical Considerations

Discontinue clopidogrel at least 5 days (preferably 7 days) before elective surgery with major bleeding risk, unless the urgency for revascularization outweighs bleeding risks 1, 3

Premature discontinuation significantly increases stent thrombosis risk, particularly catastrophic in patients with unprotected left main, bifurcating left main, or last patent coronary vessel 3

Special Populations

• Renal impairment: No dose adjustment necessary 5
• Mild-to-moderate hepatic impairment: No dose adjustment necessary 5
• Elderly patients: Standard 75 mg maintenance dose appropriate for all age groups studied 5
• No adjustment needed based on: Gender, weight, or race 5

Monitoring

No routine hematological monitoring is required 5, though in very high-risk patients (unprotected left main, last patent vessel), platelet aggregation studies may be considered with dose increase to 150 mg daily if <50% platelet inhibition is demonstrated 2