Daily Variability of Platelet Aggregation in Patients With Myocardial Infarction Treated With Prasugrel and Ticagrelor

Prasugrel and ticagrelor are two oral P2Y12 receptor antagonists recommended as a part of dual antiplatelet therapy with aspirin in patients with acute myocardial infarction. Both drugs exert comparable antiplatelet effect following a loading dose. However, pharmacodynamic differences exist between these P2Y12 receptor inhibitors. Prasugrel is a prodrug that requires hepatic activation and permanently binds to platelet P2Y12 receptors, whereas ticagrelor is an active drug and blocks P2Y12 receptors reversibly. Another important difference is that prasugrel maintenance dose is administered once daily, while ticagrelor requires next dosage every 12 hours. These fundamental distinctions may affect the degree of platelet inhibition on maintenance doses during the first days after acute myocardial infarction.

Inclusion criteria

• provision of informed consent prior to any study specific procedures
• diagnosis of acute ST-segment elevation myocardial infarction or acute non-ST-segment elevation myocardial infarction
• male or non-pregnant female, aged 18-75 years old
• provision of informed consent for angiography and percutaneous coronary intervention

Exclusion criteria

• treatment with ticlopidine, clopidogrel, prasugrel or ticagrelor within 14 days before the study enrollment
• hypersensitivity to ticagrelor or prasugrel
• contraindications for ticagrelor or prasugrel
• current treatment with oral anticoagulant or chronic therapy with low-molecular-weight heparin
• active bleeding
• history of ischemic stroke or transient ischemic attack
• history of intracranial hemorrhage
• recent gastrointestinal bleeding (within 30 days)
• history of moderate or severe hepatic impairment
• history of major surgery or severe trauma (within 3 months)
• patient required dialysis
• manifest infection or inflammatory state
• concomitant therapy with strong CYP3A inhibitors (ketoconazole, itraconazole, voriconazole, telithromycin, clarithromycin, nefazadone, ritonavir, saquinavir, nelfinavir, indinavir, atazanavir) or strong CYP3A inducers (rifampicin, phenytoin, carbamazepine, dexamethasone, phenobarbital) within 14 days and during study treatment
• body weight below 60 kg