Antiplatelet Therapy for Acute Ischemic Stroke in Patients Already on Aspirin 150mg
For patients with acute ischemic stroke already on aspirin 150mg, the recommended approach is to add clopidogrel 300mg loading dose followed by 75mg daily for 21-30 days, then return to antiplatelet monotherapy. 1
Initial Management
- For patients with acute ischemic stroke already on aspirin 150mg, continue the aspirin therapy after confirming absence of intracranial hemorrhage on brain imaging 1
- If the patient received thrombolysis (alteplase), delay initiation of any antiplatelet therapy until after the 24-hour post-thrombolysis scan has excluded intracranial hemorrhage 1
- For non-thrombolyzed patients with mild to moderate stroke (NIHSS 0-3) or high-risk TIA, add clopidogrel to the existing aspirin regimen 1, 2
Dual Antiplatelet Therapy Protocol
- Loading dose: Add clopidogrel 300mg (minimum) to 600mg (maximum) as a one-time loading dose 1, 3
- Maintenance: Continue with clopidogrel 75mg daily plus aspirin 150mg daily for a limited duration of 21-30 days 1, 4
- Dual antiplatelet therapy should be started as soon as possible after brain imaging, ideally within 12 hours but no later than 24 hours after symptom onset 1
- After 21-30 days, discontinue one of the antiplatelet agents and continue with monotherapy indefinitely 1
Evidence Supporting Dual Therapy
- The CHANCE and POINT trials demonstrated that dual antiplatelet therapy with clopidogrel plus aspirin reduced the risk of recurrent stroke compared to aspirin alone when initiated early after minor stroke or high-risk TIA 1, 2
- The INSPIRES trial showed that dual antiplatelet therapy initiated within 72 hours after stroke onset led to a lower risk of new stroke at 90 days (7.3% vs 9.2%) compared to aspirin monotherapy 2
- Short-duration DAPT (≤1 month) started during the early acute ischemic phase was associated with less bleeding than longer DAPT and greater reduction of recurrent strokes compared with monotherapy 4
Duration Considerations
- The optimal duration of dual antiplatelet therapy is 21-30 days 1
- Continuing dual therapy beyond this period increases bleeding risk without additional benefit in stroke prevention 1, 4
- In the POINT trial, for every 1000 patients treated with clopidogrel plus aspirin for 90 days, 15 ischemic strokes would be prevented but 5 major hemorrhages would result 1
Monitoring and Safety
- Monitor for bleeding complications, especially during the dual antiplatelet therapy period 1, 2
- The INSPIRES trial reported moderate-to-severe bleeding in 0.9% of patients on dual therapy versus 0.4% on aspirin alone 2
- Perform dysphagia screening before administering oral medications; in dysphagic patients, medications may be given via enteral tube 1
Special Considerations
- For patients with severe stroke, the benefit of adding clopidogrel is less established 1
- In patients with atrial fibrillation, oral anticoagulation is generally preferred over dual antiplatelet therapy for long-term secondary prevention, but should typically be initiated 1-2 weeks after stroke onset 1
- The loading dose of clopidogrel is essential for rapid platelet inhibition, as the standard 75mg dose takes approximately 5 days to achieve maximal effect 1