Can we give single antiplatelet agent Aspirin (acetylsalicylic acid) 150mg for the initial 3 months after an acute stroke?

Single Antiplatelet Therapy (Aspirin 150mg) for Initial 3 Months After Acute Stroke

Yes, aspirin 150mg daily is appropriate for the initial 3 months after acute ischemic stroke, though guidelines recommend starting with a higher loading dose (160-325mg) within 24-48 hours, then continuing with a maintenance dose of 75-325mg daily for long-term secondary prevention. 1, 2

Acute Phase Dosing (First 24-48 Hours)

• Start with a loading dose of 160-325mg within 24-48 hours of stroke onset after brain imaging excludes hemorrhage 1, 2
• The initial dose should be chewed (not enteric-coated) to achieve rapid platelet inhibition 1
• If oral administration is not possible, aspirin can be given rectally (325mg) or via nasogastric tube 1, 3
• Do NOT give aspirin within 24 hours of thrombolytic therapy due to increased bleeding risk 1, 2

Maintenance Dosing (After Initial 48 Hours Through 3 Months)

• Continue with 75-325mg daily for ongoing secondary prevention 1, 2
• Your proposed dose of 150mg falls within the recommended therapeutic range and is appropriate 1, 4
• Lower maintenance doses (75-100mg) have similar efficacy to higher doses with fewer gastrointestinal side effects 2

Evidence Supporting Single Antiplatelet Therapy

• Aspirin reduces early recurrent ischemic stroke by approximately 10 events per 1,000 patients treated 4, 3
• The primary benefit is reduction of early recurrent stroke rather than limitation of initial neurological damage 1
• Treatment improves long-term functional outcomes, reducing death or dependency at 6 months 3
• The risk of hemorrhagic stroke is only slightly increased (approximately 2 additional hemorrhagic strokes per 1,000 patients) and does not offset the benefits 4, 5

Important Contraindications and Exceptions

Do NOT use single antiplatelet therapy in these situations:

• Minor stroke (NIHSS ≤3-5) or high-risk TIA (ABCD2 ≥4): These patients should receive dual antiplatelet therapy (aspirin + clopidogrel) for 21-30 days, then transition to single antiplatelet therapy 1, 6
• Within 24 hours of thrombolytic therapy: Aspirin must be delayed to avoid increased bleeding risk 1, 2
• Patients requiring anticoagulation: Those with mechanical heart valves, intracardiac thrombi, or atrial fibrillation may need anticoagulation instead 1
• Active bleeding or aspirin allergy: Consider clopidogrel 75mg daily as an alternative 1

Comparison to Anticoagulation

• Aspirin is superior to anticoagulation for acute ischemic stroke in most patients 1
• Unfractionated heparin and low-molecular-weight heparins do not reduce stroke recurrence and increase intracranial hemorrhage risk 1, 5
• Even in patients with atrial fibrillation, subcutaneous heparin in the acute phase showed no net benefit due to offsetting bleeding complications 1

Duration Beyond 3 Months

• Continue single antiplatelet therapy indefinitely for long-term secondary stroke prevention 1, 2
• The 3-month timepoint is not a stopping point but rather a transition from acute to chronic management 1
• Long-term dual antiplatelet therapy beyond 90 days increases bleeding risk without clear benefit 2

Common Pitfalls to Avoid

• Do not substitute aspirin for IV thrombolysis in eligible patients—aspirin is adjunctive, not a replacement 1, 2
• Do not use doses above 325mg—higher doses increase bleeding without improving efficacy 2
• Do not combine aspirin with clopidogrel beyond 3 months in most stroke patients due to increased bleeding risk 1, 2
• Do not use clopidogrel monotherapy or dual antiplatelet therapy for routine acute ischemic stroke treatment outside the minor stroke/high-risk TIA population 1