Duration of Dual Antiplatelet Therapy After Ischemic Stroke
For patients who have had an ischemic stroke, dual antiplatelet therapy (DAPT) should be used for 21-30 days only, specifically in those with minor stroke (NIHSS ≤3) or high-risk TIA (ABCD2 ≥4), followed by lifelong single antiplatelet therapy. 1
Treatment Algorithm Based on Stroke Severity
Minor Stroke or High-Risk TIA (NIHSS ≤3, ABCD2 ≥4)
Initiation timing and loading doses:
- Start DAPT as soon as possible after brain imaging excludes hemorrhage, ideally within 12 hours and no later than 24 hours of symptom onset 1
- Give loading doses: Clopidogrel 300-600 mg plus Aspirin 160-325 mg 1
Maintenance regimen:
- Aspirin 81 mg daily plus Clopidogrel 75 mg daily for 21-30 days 1
- Alternative: Aspirin 75-100 mg daily plus Ticagrelor 90 mg twice daily for 30 days 1
After DAPT completion:
- Switch to single antiplatelet therapy (aspirin 81-325 mg daily OR clopidogrel 75 mg daily) and continue indefinitely 1
Moderate to Severe Stroke
- Single antiplatelet therapy only (aspirin 160 mg loading dose, then 81-325 mg daily) 1
- DAPT is not recommended for moderate-severe strokes 1
Critical Evidence Supporting 21-30 Day Duration
The Canadian Stroke Best Practice guidelines specifically limited DAPT to 21-30 days (rather than the 90 days studied in POINT trial) based on risk-benefit analysis 1:
- For every 1000 patients treated with DAPT for 90 days: 15 ischemic strokes prevented but 5 major hemorrhages caused 1
- Major hemorrhage risk significantly increased with 90-day DAPT (0.9% vs 0.4%, HR 2.32) 1
- The World Stroke Organization 2023 guidelines similarly recommend 21 days for aspirin-clopidogrel combination 1
Important Caveats and Contraindications
Do NOT use DAPT if:
- Patient received thrombolysis (alteplase) - delay antiplatelet therapy until 24-hour post-thrombolysis scan excludes hemorrhage 1
- Cardioembolic stroke mechanism - these patients require anticoagulation, not DAPT 1
- High bleeding risk exists (prior bleeding on DAPT, coagulopathy, oral anticoagulant use) 1
Special consideration for carotid stenosis:
- Patients with high-grade carotid stenosis requiring urgent endarterectomy may need aspirin monotherapy instead of DAPT to reduce perioperative bleeding risk 1
GI protection:
- Consider proton pump inhibitor in patients at higher risk of GI bleeding during DAPT 1
Why Not Longer Duration?
Prolonged DAPT (≥1 year) after stroke is not recommended because 1, 2:
- When continued for 2-3 years, DAPT shows no additional reduction in ischemic stroke risk 1
- Bleeding risk accumulates over time, negating any potential benefit 1, 2, 3
- The benefit of DAPT is concentrated in the early high-risk period (first 21-90 days) after the index event 1, 2
The evidence is clear: short-term DAPT (21-30 days) provides optimal risk-benefit ratio, while prolonged therapy increases bleeding without additional stroke prevention benefit. 1, 2