Anti-Platlet (Drugs)

Question 1

Acetylsalicylic Acid

Answer 1

NSAID
- Anaesthetic and Anti-platelet

MOA:
- Irreversibly inhibits COX-1
–> Prevents TXA2 synthesis
–> Can no longer stimulate platelet aggregation

• Inhibition lasts for life span of platelets

Question 2

Ticlopidine

Answer 2

Thienopyridines (Pro-drug)
- Anti-platlets

MOA:
- Irreversible, non-competitive antagonists of ADP
–> Inhibits P2Y12 and blocks ADP from binding preventing Platelet aggregation

• Causes Side Effects
• Low neutrophils
• Low platelet counts

Question 3

Clopidogrel

Answer 3

Thienopyridines (Pro-drug)
- Anti-platlets

MOA:
- Irreversible, non-competitive antagonists of ADP
–> Inhibits P2Y12 and blocks ADP from binding preventing Platelet aggregation

• Some patients are poor metabolizers

Question 4

Prasugrel

Answer 4

Thienopyridines (Pro-drug)
- Anti-platlets

MOA:
- Irreversible, non-competitive antagonists of ADP
–> Inhibits P2Y12 and blocks ADP from binding preventing Platelet aggregation

• Fastest biotransformation, causes more bleeding

Question 5

Ticagrelor

Answer 5

Non-Thienopyridine P2Y12 Antagonist
- Anti-platelet

MOA:
- Reversible allosteric P2Y12 antagonist

• Worse adverse effects than clopidogrel

Question 6

DAPT

Answer 6

Duel Anti-Platelet Therapy

• ASA + Clopidogrel / Ticagrelor / Prasugrel

Question 7

Dipyridamole

Answer 7

PDE Inhibitor
- Anti-Platelet

MOA:
- Prevents PDE from breaking cAMP
–> More cAMP = More inhibition of platelets

Secondary MOA:
- Decrease Platelet TXA2
- Increase endothelial PGI2 synthesis
- Blocks adenosine reuptake
(platelet inhibitor)

Question 8

Abciximab

Answer 8

Glycoprotein IIb/IIIa Antagonist
- Anti-platelet

MOA:
- GPIIb/III Antagonist
–> Prevents activation of complex
–> Fibrinogen binds to inactivated complex
–> Nothing happens
–> Prevent platelet aggregation

Question 9

Eptifibatide

Answer 9

Glycoprotein IIb/IIIa Antagonist
- Anti-platelet

MOA:
- Competes with Fibrinogen for GPIIb/III
–> Lowers Fibrinogen binding to complex
–> Prevents platelet aggregation

Question 10

Tirofiban

Answer 10

Glycoprotein IIb/IIIa Antagonist
- Anti-platelet

MOA:
- Competes with Fibrinogen for GPIIb/III
–> Lowers Fibrinogen binding to complex
–> Prevents platelet aggregation

Question 11

Vorapaxar

Answer 11

Protease Activated Receptor 1 Antagonist
(Competitive antagonist of PAR 1)
- Anti Platelet

MOA:
- Inhibits thrombin activating platelets

• Causes severe bleeding