What is the recommended duration of dual antiplatelet therapy (DAPT) with aspirin and clopidogrel after a Transient Ischemic Attack (TIA)?

Duration of Dual Antiplatelet Therapy After TIA

For patients with high-risk TIA (ABCD2 score ≥4), dual antiplatelet therapy with aspirin plus clopidogrel should be initiated within 12-24 hours and continued for 21 days, followed by single antiplatelet therapy. 1

Initiation and Loading Dose

• Start DAPT as early as possible, ideally within 12-24 hours of symptom onset (and no later than 7 days after onset) 1
• Administer loading doses: aspirin 160-325 mg PLUS clopidogrel 300-600 mg 2
• Continue with maintenance doses: aspirin 81 mg daily plus clopidogrel 75 mg daily 1, 2

Duration: 21 Days is the Standard

• The optimal duration is 21 days based on pooled analysis of the CHANCE and POINT trials, which demonstrated that the benefit of DAPT is confined to the first 21 days after the event 3
• The American Heart Association/American Stroke Association guidelines specify a range of 21-90 days, but 21 days represents the sweet spot where efficacy is maximized while minimizing bleeding risk 1
• The European Stroke Organisation makes a strong recommendation for exactly 21 days of aspirin plus clopidogrel based on high-quality evidence 4

After 21 Days: Transition to Single Antiplatelet

• Switch to single antiplatelet therapy (either aspirin 81 mg daily OR clopidogrel 75 mg daily) after completing the 21-day DAPT course 1, 5
• Continue single antiplatelet therapy indefinitely for long-term secondary prevention 5

Alternative Regimen (Ticagrelor-Based)

• An alternative is ticagrelor 180 mg loading dose plus aspirin, followed by ticagrelor 90 mg twice daily plus aspirin for 30 days, then single antiplatelet therapy 2
• This represents a weak recommendation based on moderate-quality evidence 4

Critical Safety Considerations

• Do NOT continue DAPT beyond 90 days - prolonged use significantly increases major hemorrhage risk (hazard ratio 2.22-2.32) without additional benefit 1, 5
• Major hemorrhage risk is higher with DAPT (0.9%) compared to aspirin alone (0.4%), though the absolute increase is small 6
• The benefit-to-risk ratio favors DAPT only during the first 21 days, with most stroke prevention occurring in the first week 3

Who Qualifies for DAPT After TIA?

• High-risk TIA defined as ABCD2 score ≥4 1
• Noncardioembolic mechanism (if cardioembolic, anticoagulation is preferred) 1
• Presenting within 24 hours of symptom onset 1, 4

Common Pitfalls to Avoid

• Do not use DAPT for low-risk TIA (ABCD2 score <4) - use single antiplatelet therapy instead 5
• Do not delay initiation - efficacy is time-dependent, with maximum benefit when started within the first 24 hours 1, 3
• Do not continue DAPT indefinitely - the bleeding risk outweighs benefit after 21-30 days 1, 5, 3
• Do not use triple antiplatelet therapy - this is associated with excess hemorrhage risk 1