Ticagrelor: positive, negative and misunderstood properties as a new antiplatelet agent

Dual antiplatelet therapy is essential for the management of acute coronary syndrome. In particular, combination therapy using aspirin with a platelet ADP (i.e. P2Y12 ) receptor inhibitor, such as clopidogrel, prasugrel or, more recently, ticagrelor, has been recommended for patients with acute coronary syndrome. Pharmacological agents that reversibly inhibit platelet aggregation without metabolic activation in the liver are believed to reduce cardiovascular mortality compared with the current drug of choice for antiplatelet therapy, namely clopidogrel. These findings are based on a multicentre, double-blind, double-dummy, randomized controlled trial. Numerous factors are postulated to contribute to the improved survival of patients who take ticagrelor compared with those taking clopidogrel, including the risk of myocardial infarction, heart failure, arrhythmia and bleeding. In addition, clopidogrel may lead to a much higher incidence of infection. Although ticagrelor has recently been approved for use in the US and exhibits superiority over other antiplatelet agents, certain concerns remain regarding its use, including lung injury and dyspnoea, thus raising the issue of its true superiority over clopidogrel or prasugrel. Recent studies into ticagrelor report conflicting data, with certain aspects of its mechanisms of action still not fully understood. Ticagrelor has beneficial effects following its clinical application, such as achieving overall higher reductions in mortality compared with the use of clopidogrel and prasugrel. Harmful effects associated with the use of ticagrelor include a higher incidence of dyspnoea and major bleeding compared with clopidogrel.