4. Ticagrelor is a new, direct, reversible P2Y12 receptor antagonist, which has rapid and potent antiplatelet effect. In patients who have an acute coronary syndrome with or without ST-segment elevation, treatment with ticagrelor as compared with clopidogrel significantly reduced the rate of death from vascular causes, myocardial infarction, or stroke without an increase in the rate of overall major bleeding.