Abstract
Dual antiplatelet therapy including P2Y12 inhibitor is mandatory to prevent stent thrombosis in acute coronary syndrome and prasugrel is more frequently used in Japanese patients than clopidogrel due to its poor metabolizer profile. We describe a case of a patient with prasugrel resistance who was switched to an appropriate antiplatelet therapy based on platelet function testing. Although prasugrel resistance is rare and platelet function test is not common in daily practice, it is important to be familiar with alternative drugs for prasugrel resistance and how to suspect and treat these patients. LEARNING OBJECTIVE: Effects of antiplatelet therapy can be assessed by platelet function test (platelet aggregation test, VerifyNow, etc.).Although routine use of platelet function test has not been recommended, it might be useful in cases with repeated thrombotic events.