Normal Plavix (Clopidogrel) Dosing
The standard maintenance dose of clopidogrel is 75 mg once daily, with a 300 mg loading dose recommended when an immediate antiplatelet effect is needed within hours, particularly in acute coronary syndrome settings. 1
Standard Dosing Regimens
For Acute Coronary Syndrome (ACS)
Loading Dose:
- 300-600 mg oral loading dose should be administered as soon as possible when ACS is suspected or confirmed 2
- The 600 mg loading dose achieves faster and more complete platelet inhibition compared to 300 mg, though both are acceptable 2
- For patients already on chronic 75 mg daily who develop ACS, re-loading with 600-900 mg is more effective than repeating 300 mg 3
- Loading should occur as early as possible before PCI (at least 2-6 hours prior when feasible) 2
Maintenance Dose:
- 75 mg once daily following the loading dose 1
- Continue for at least 12 months after stent placement (bare-metal or drug-eluting) unless bleeding risk outweighs benefit 2
- May extend beyond 12-15 months in selected patients with drug-eluting stents 2
For Stable Cardiovascular Disease
No Loading Dose Required:
- 75 mg once daily without a loading dose for patients with recent MI, recent stroke, or established peripheral arterial disease 1
- Initiating without a loading dose delays antiplatelet effect by several days 1
Special Clinical Scenarios
Post-Fibrinolytic Therapy in STEMI
- 300 mg loading dose for patients under 75 years receiving fibrinolytic therapy 2
- No loading dose recommended for patients ≥75 years due to increased bleeding risk 2
- Continue 75 mg daily for at least 14 days, though 12 months is reasonable 2
Elective PCI
- 600 mg loading dose at least 2 hours before procedure (or 300 mg at least 6 hours before) 2
- For patients with aspirin contraindication: 300-600 mg at least 6 hours before PCI 2
Patients on Chronic Clopidogrel Requiring PCI
- Additional 300-600 mg loading dose before the procedure, even if already on 75 mg daily 3
- 900 mg total loading dose (given in divided doses) provides superior platelet inhibition compared to 300-600 mg in patients on chronic therapy 3
Duration of Therapy
Minimum Duration by Stent Type:
- Bare-metal stent: At least 1 month, ideally up to 12 months 2
- Drug-eluting stent: At least 12 months 2
- Post-ACS without stent: At least 12 months 2
Important Caveats and Contraindications
When to Withhold Clopidogrel
- Discontinue 5-7 days before elective CABG to reduce surgical bleeding risk 2
- The only absolute contraindications are active pathological bleeding or documented hypersensitivity 1
Patients Who Should NOT Receive Prasugrel (Alternative P2Y12 Inhibitor)
- Prior stroke or TIA is a contraindication for prasugrel, NOT clopidogrel 2
- Age ≥75 years or weight <60 kg increases bleeding risk with prasugrel but not clopidogrel 2
Bleeding Risk Considerations
- Dual antiplatelet therapy (clopidogrel + aspirin) increases major bleeding by approximately 1% (from 2.7% to 3.7%) compared to aspirin alone 2
- This modest bleeding increase is outweighed by the 20% reduction in cardiovascular death, MI, and stroke in ACS patients 2
Drug Interactions
- Avoid concomitant use with strong CYP2C19 inhibitors (omeprazole, esomeprazole) as they reduce clopidogrel's antiplatelet activity 2
Renal Function
- No dose adjustment required for renal insufficiency; standard 75 mg daily maintenance dose is appropriate 4
Clinical Evidence Supporting Dosing
The 300 mg loading dose followed by 75 mg daily was the regimen used in landmark trials establishing clopidogrel's efficacy and safety profile 2. Higher loading doses (600 mg) achieve more rapid platelet inhibition within 2-4 hours, which is particularly valuable when PCI is planned urgently 2, 3. The RELOAD study demonstrated that 900 mg loading in patients already on chronic clopidogrel reduces suboptimal response rates from 23.6% (with 300 mg) to 5.3% 3.