Anti-platelets

Question 1

Aspirin MOA?

Answer 1

Inhibits COX-1 enzyme=> AA not converted into PGH2=> Thromboxane not produced=> Decreased platelet aggregation.

Question 2

Dipyramidole MOA?

Answer 2

Phosphodiesterase inhibitor.

- Decreases cAMP and cGMP=> Inhibits platelet activation and aggregation.

Question 3

Clopidogrel MOA?

Answer 3

ADP receptor antagonist. (P2Y12 rec. antagonist).
Acts as a pro-drug. Activated by CP450.
Irreversibly binds to P2Y12 rec.=> Blocks amplification and inhibits Thromboxane production.

Question 4

Prasugrel MOA?

Answer 4

ADP receptor antagonist. (P2Y12 rec. antagonist).
Acts as a prodrug. Activated by CP450.
Irreversibly binds to P2Y12 rec.=> Blocks amplification and inhibits thromboxane production.

Greater inhibitory effect than clopidogrel but greater risk of bleeding.

Question 5

Ticagrelor MOA?

Answer 5

ADP receptor antagonist (P2Y12 rec. antagonist)
Acts directly.
Reversibly inhbits P2Y12 rec=> Blocks amplification and inhibits Thromboxane production.

Question 6

GP IIb/IIIa antagonists MOA?

Answer 6

Abciximab, Tirofiban, Eptifibatide.

Abciximab binds to RGD site on GP IIb/IIIa receptor=> Prevents fibrinogen binding.