We randomly assigned 5170 patients within 24 hours after onset of minor stroke or high-risk transient ischemic attack to clopidogrel-aspirin therapy ( loading dose of 300 mg of clopidogrel on day 1 , followed by 75 mg of clopidogrel per day for 90 days , plus 75 mg of aspirin per day for the first 21 days ) or to the aspirin-alone group ( 75 mg/d for 90 days ) .