 The recommended antiplatelet treatment regimen for patients affected by acute coronary syndromes ACS and those undergoing percutaneous coronary intervention PCI consists in the combination of aspirin and a P2Y12 receptor inhibitor. More potent P2Y12 receptor inhibitors, such as ticagrelor, have been developed which are associated with less response variability than clopidogrel and better clinical outcomes. Ticagrelor use has increased significantly because of its more expanded Food and Drug Administration FDA indications compared with prasugrel. However, despite the evidence for sustained efficacy and safety, many physicians limit treatment duration with ticagrelor to the early phases following an ACS mostly due to cost issues and concerns about increased bleeding. Therefore, it is very common in clinical practice to switch patients while on maintenance dosing MD with ticagrelor to treatment with clopidogrel. However, the pharmacodynamic PD effects of switching from ticagrelor to clopidogrel remain unknown. Therefore, the aim of this investigation is to evaluate the PD effects of switching from ticagrelor to clopidogrel. 