May be useful in selected patients with ischemic/thrombotic events while compliant with a clopidogrel regimen Clinical utility not rigorously established but less likely to be necessary given lesser degree of variation in response Clinical utility not rigorously established but less likely to be necessary given lesser degree of variation in response Genotyping Identifies patients with a diminished (CYP2C19 *2, *3 alleles) or enhanced (CYP2C17 allele) to form active metabolite. Role of genotyping in clinical management not rigorously established. Clinical utility not rigorously established but less likely to be necessary given lesser degree of variation in response Clinical utility not rigorously established but less likely to be necessary given lesser degree of variation in response Risk of bleeding Standard dosing with clopidogrel is associated with less bleeding than with prasugrel and ticagrelor. Higher doses of clopidogrel are associated with greater risk of bleeding than standard dose clopidogrel. Risk of spontaneous, instrumented, and fatal bleeds higher with prasugrel compared with standard dose clopidogrel Risk of non-CABG bleeds higher with ticagrelor compared with standard dose clopidogrel Transition to surgery Wait 5 d after last dose Wait 7 d after last dose Wait 5 d after last dose ASA indicates aspirin; BMS, bare-metal stent; DES, drug-eluting stent; CABG, coronary artery bypass graft; PCI, percutaneous coronary intervention; PPI, proton pump inhibitor; TIA, transient ischemic attack; and UA/NSTEMI, unstable angina/non ST-elevation myocardial infarction. Appendix 5. Flowchart for Class I and Class IIa Recommendations for Initial Management of UA/NSTEMI *A loading dose followed by a daily maintenance dose of either clopidogrel (LOE: B), prasugrel (in PCI-treated patients), or ticagrelor (LOE: C) should be administered to UA/NSTEMI patients who are unable to take ASA because of hypersensitivity or major GI intolerance. 