The PROTEUS study is a randomized, cross-over, open-label, pharmacodynamic trial designed to compare the antiplatelet effect of reduced maintenance doses of prasugrel and ticagrelor in stable patients who recently had non-ST-elevation acute coronary syndrome (non-ST-elevation myocardial infarction or unstable angina).

Inclusion Criteria:

• provision of informed consent prior to any study specific procedures
• diagnosis of non-ST-segment elevation acute coronary syndrome (non-ST-segment elevation myocardial treatment or unstable angina)
• male or non-pregnant female, aged 18-75 years old

Exclusion Criteria:

• known hypersensitivity to ticagrelor or prasugrel
• presence of contraindications for ticagrelor or prasugrel
• current treatment with oral anticoagulant or chronic therapy with low-molecular-weight heparin
• 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
• 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