Question

Which of the following is a P2Y₁₂ enzyme inhibitor?

• A. Clopidogrel
• B. Aspirin
• C. Dipyridamole
• D. Tirofiban

Hint:

P2Y$_12$ inhibitors like clopidogrel are crucial in dual antiplatelet therapy, often combined with aspirin, for preventing cardiovascular events.

Answer 1

The Correct Option is A

P2Y12 is the ADP receptor on platelets that, once triggered, drives the platelets to clump together. Blocking this specific receptor is one way antiplatelet drugs prevent clot formation.

1. Clopidogrel: After liver activation, it binds P2Y12 irreversibly and shuts off ADP-driven platelet activation, matching the mechanism the question describes.
2. Aspirin: Targets the COX-1 enzyme and thromboxane production instead, a different platelet pathway altogether.
3. Dipyridamole: Raises cAMP inside platelets through phosphodiesterase inhibition, again bypassing the P2Y12 receptor.
4. Tirofiban: Blocks glycoprotein IIb/IIIa, the receptor platelets use to bind fibrinogen at the very last step of aggregation, not the ADP receptor upstream.

Only one of these four drugs has the ADP receptor itself as its target.

So the correct answer is Clopidogrel.