Antiplatelet Therapy for Lacunar Infarction
For lacunar infarction, start with aspirin 160 mg loading dose immediately after brain imaging excludes hemorrhage, then continue 81-325 mg daily indefinitely. 1
Acute Phase Management
Initial Loading Dose
- Administer aspirin 160 mg as a one-time loading dose immediately after CT/MRI confirms ischemic stroke and excludes intracranial hemorrhage 1, 2
- Perform dysphagia screening before oral administration 1
- If thrombolysis (tPA) was given, delay aspirin until 24-hour post-thrombolysis scan excludes hemorrhage 1
Maintenance Therapy Selection
Standard approach (most lacunar strokes):
- Continue aspirin 81-325 mg daily indefinitely 1
- Lower doses (81-100 mg) provide equivalent efficacy with fewer gastrointestinal side effects 1, 3, 4
Dual antiplatelet therapy (DAPT) - only for specific high-risk scenarios:
- Reserved for minor stroke (NIHSS 0-3) or very high-risk TIA presenting within 24 hours 1
- Loading: clopidogrel 300-600 mg + aspirin 160 mg 1, 5
- Maintenance: clopidogrel 75 mg + aspirin 81 mg daily for 21-30 days only 1, 6
- Then transition to monotherapy (aspirin or clopidogrel alone) 1
Why Aspirin is Preferred Over Clopidogrel for Lacunar Stroke
Aspirin monotherapy is the standard of care for typical lacunar infarction because:
- Established Level A evidence for stroke prevention in this population 1
- No proven superiority of clopidogrel over aspirin for lacunar stroke specifically 7
- Class I evidence shows adding clopidogrel to aspirin in patients with lacunar stroke already on aspirin does not reduce recurrent stroke risk (HR 0.91,95% CI 0.61-1.37) 7
Clopidogrel monotherapy (75 mg daily) is reserved for:
- Aspirin allergy or intolerance 1
- Patients already on aspirin who had breakthrough lacunar stroke (though evidence is weak - Level B) 1
- If rapid loading needed: 300 mg loading dose, then 75 mg daily 1, 8
Dosing Algorithm
Step 1 - Acute phase (first 24 hours):
- Aspirin 160 mg loading dose (after imaging excludes hemorrhage) 1
Step 2 - Determine if DAPT criteria met:
- NIHSS 0-3 AND within 24 hours of symptom onset AND non-cardioembolic?
Step 3 - Maintenance (day 2 onwards):
- DAPT group: Aspirin 81 mg + clopidogrel 75 mg daily for 21-30 days, then switch to monotherapy 1, 6
- Monotherapy group: Aspirin 81-325 mg daily indefinitely (prefer 81-100 mg for better tolerability) 1
Critical Caveats
Avoid these common pitfalls:
- Do not use DAPT for typical lacunar strokes beyond 24 hours from onset - no benefit, increased bleeding risk 1
- Do not continue DAPT beyond 30 days - bleeding risk (0.9% vs 0.4%) outweighs benefit 1
- Do not give aspirin within 24 hours of tPA administration - increased hemorrhage risk 1
- Do not use aspirin doses >325 mg - no additional benefit, more bleeding 1, 9, 10
- Do not assume clopidogrel is superior to aspirin for lacunar stroke - it is not 7
Special populations:
- Dysphagia: aspirin 80 mg via enteral tube or 325 mg rectal suppository daily 1
- Clopidogrel via enteral tube: 75 mg daily 1
- Consider GI protection (PPI) if high bleeding risk, but avoid omeprazole/esomeprazole with clopidogrel 1, 8
Evidence Quality
The Canadian Stroke Best Practice Recommendations (2018) provide the most recent and comprehensive Level A evidence for this approach 1. The recommendation for aspirin monotherapy in standard lacunar stroke is supported by multiple high-quality trials, while DAPT is only justified in the narrow window of minor stroke/high-risk TIA within 24 hours based on CHANCE and POINT trials 1. Research specifically examining lacunar stroke populations confirms aspirin's efficacy (HR 0.67 for recurrence) 3 and demonstrates no added benefit from dual therapy in typical cases 7.