When to reduce high dose aspirin (acetylsalicylic acid) in patients with a history of stroke?

When to Reduce High Dose Aspirin in Stroke Patients

For patients with a history of stroke, high-dose aspirin (160-325 mg) should be reduced to a maintenance dose of 81-100 mg daily after 21-30 days of initial treatment, depending on the specific stroke subtype and whether dual antiplatelet therapy was used. 1

Initial Aspirin Dosing in Acute Stroke

• In patients with acute ischemic stroke or TIA who were not previously on antiplatelet therapy, a single loading dose of 160-325 mg aspirin should be administered after intracranial hemorrhage is ruled out on neuroimaging 2, 1
• For patients with acute ischemic stroke who cannot take oral medications due to dysphagia, rectal aspirin 325 mg daily or aspirin 81 mg daily via enteral tube are appropriate alternatives 1, 2
• In patients treated with tPA (tissue plasminogen activator), aspirin therapy should be delayed until after the 24-hour post-thrombolysis scan has excluded intracranial hemorrhage 1

Transitioning from High to Low Dose Aspirin

For Minor Ischemic Stroke or High-Risk TIA with Dual Antiplatelet Therapy (DAPT):

• For patients with minor ischemic stroke (NIHSS ≤3) or high-risk TIA (ABCD2 ≥4) on DAPT with aspirin and clopidogrel:

  • Initial loading doses: aspirin 160-325 mg and clopidogrel 300-600 mg 1, 2
  • DAPT is indicated for 21 days 1
  • After 21 days, transition to single antiplatelet therapy with aspirin 81 mg daily or clopidogrel 75 mg daily for long-term secondary prevention 1

• For patients with mild-moderate ischemic stroke (NIHSS ≤5) or high-risk TIA on DAPT with aspirin and ticagrelor:

  • Initial loading doses: aspirin 300-325 mg and ticagrelor 180 mg 1, 2
  • DAPT is indicated for 30 days 1
  • After 30 days, transition to long-term single antiplatelet therapy with aspirin 81-100 mg daily 1

For Standard Antiplatelet Monotherapy:

• For patients on aspirin monotherapy for secondary stroke prevention:
  • Initial high-dose aspirin (160-325 mg) in acute phase 1, 3
  • After the acute phase (typically 2-4 weeks), transition to a maintenance dose of 81-325 mg daily for long-term secondary prevention 1
  • The lowest effective dose (81-100 mg) is generally preferred for long-term therapy to minimize bleeding risk while maintaining efficacy 1

Evidence for Aspirin Dose Reduction

• Long-term antiplatelet therapy with aspirin 81-325 mg daily is indicated for secondary stroke prevention in patients with non-cardioembolic ischemic events 1
• Lower doses of aspirin (81-100 mg) are as effective as higher doses for long-term secondary prevention while potentially reducing gastrointestinal side effects 1, 4
• The American Heart Association/American Stroke Association guidelines recommend aspirin 50-325 mg daily for secondary stroke prevention, with no additional benefit demonstrated for doses above this range 1

Special Considerations

• For patients with extracranial carotid or vertebral artery dissection, antiplatelet therapy should be continued for at least 3 months before considering dose reduction 1
• For patients already taking aspirin at the time of stroke, changing to another antiplatelet medication (such as clopidogrel) may be considered rather than increasing the aspirin dose 1
• Continuous use of DAPT (aspirin plus clopidogrel) for >90 days is associated with excess risk of hemorrhage and is not recommended for routine long-term secondary prevention 1

Clinical Pitfalls to Avoid

• Avoid enteric-coated aspirin for the initial loading dose as it has a slower onset of action 2
• Do not continue high-dose aspirin (>325 mg daily) long-term as it provides no additional benefit over lower doses but increases bleeding risk 1, 4
• Avoid continuing dual antiplatelet therapy beyond the recommended duration (21-30 days depending on the regimen) unless there is a specific indication, as prolonged DAPT increases bleeding risk without additional benefit for most patients 1