Multiple-ascending dose ( MAD ) study : Japanese ( n = 36 ) and Caucasians ( n = 36 ) received single doses of 100 mg or 300 mg ticagrelor ( day 1 ) , twice-daily 100 mg or 300 mg ticagrelor , or placebo ( days 4 9 ) , and single doses of 100 mg or 300 mg ticagrelor ( day 10 ) .