A 65-year-old man presented with gradually worsening exertional angina, and underwent percutaneous coronary intervention with a drug-eluting stent. He was advised to take clopidogrel in addition to aspirin, atenolol and simvastatin.
What is the predominant mechanism through which clopidogrel inhibits platelet aggregation?
A: enhances the effect of circulating antithrombin
B: inhibits binding of adenosine diphosphate
C: inhibits cyclo-oxygenase-1
D: irreversibly binds glycoprotein IIb/IIIa receptor sites
E: prevents production of thromboxane A2
Correct answer: B Explanation B is the best answer. Clopidogrel irreversibly inhibits platelet aggregation via P2Y12 class ADP receptors.
A: Heparin enhances the activity of circulating antithrombin.
C: Aspirin is a weakly selective COX-1 inhibitor.
D: Several drugs bind glycoprotein IIb/IIIa receptor sites on platelets, thereby preventing aggregation. Abciximab has high affinity.
E: Aspirin inhibits production of thromboxane A2, through COX-1 inhibition.