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Chapter 16. Antiplatelet Therapies in Contemporary Percutaneous Coronary Intervention

Ticlopidine was the first P2Y12 inhibitor to be used clinically for dual antiplatelet therapy after stent placement. Ticlopidine was quickly replaced by clopidogrel, however, because of which of the following disadvantages or side effects?

A. Twice-daily dosing

B. High incidence of gastrointestinal upset

C. Neutropenia/thrombocytopenia

D. All of the above

The correct answer is D

Ticlopidine 250 mg twice a day (along with aspirin) was the antiplatelet therapy used in the first clinical study to prove that antiplatelet therapy was superior to anticoagulation (ie, warfarin) in patients who received stents. However, there were a significant proportion (8%-10%) of patients who suffered nausea and diarrhea while taking ticlopidine. More serious bone marrow suppression was less frequent. Clopidogrel was better tolerated, did not cause bone marrow suppression, and was dosed once daily—all significant advantages.

The TRITON-TIMI 38 trial compared prasugrel to clopidogrel in patients with acute coronary syndrome (ACS) receiving drug-eluting stents. Which of the following subgroups was identified in a post hoc analysis as patients who did not benefit from prasugrel because of an excess of bleeding complications?

A. Patients over the age of 75

B. Patients over 80 kg in weight

C. Patients with a prior transient ischemic attack (TIA)

D. A and C

E. B and C

F. A, B, and C

The correct answer is D

Patients in the TRITON-TIMI 38 trial benefitted from more reliable protection from ischemic events provided by prasugrel compared to clopidogrel, although at a cost of more frequent serious bleeding events. For the majority of patients in the trial, the net effect was still benefit, even when considering bleeding. Post hoc analysis identified 3 groups in whom the bleeding was equal to ischemia prevention, and so there was no benefit: patients older than 75, patients with body weight less than or equal to 60 kg, and patients with a prior TIA or stroke. These findings led to labeling instructions that indicate that use of this medication should be restricted in patients who meet these criteria.

Which of the following antiplatelet medications achieves its therapeutic effect by interfering with the functioning of the P2Y12 receptor on platelets?

A. Vorapaxar

B. Aspirin


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