Pharm: Antiplatelet Drugs

Question 1

What is the general mechanism of anti-platelet drugs?

Answer 1

Inhibition of primary hemostatic plug formation, aggregation, activation and release mechanisms

Question 2

Describe the contents of light and dark granules

Answer 2

Light: PF4, beta-thromboglobulin, PDGF
Dark: Ca2+, Serotonin, ATP/ADP

Question 3

What are the products of platelet activation and endothelial interaction?

Answer 3

Prostaglandin derivatives
Endoperoxides
Thromboxanes

Question 4

What site do anti-platelet have activity in that anticoagulants do not?

Answer 4

The arterial circulation

Question 5

What are the main classes of antiplatelet agents?

Answer 5

1) Aspirin
2) COX inhibitors
3) NSAIDs
4) ADP receptor inhibitors
5) Dipyridamole
6) Cilostazol
7) GPIIb/IIIa inhibitors
8) Prostacyclin analogue

Question 6

What are the most widely used ADP receptor inhibitors?

Answer 6

Clopidogrel and prasugrel

Question 7

Which ADP receptor inhibitors are prodrugs that require liver transformation?

Answer 7

Ticlopidine, Clopidogrel and prasugrel

Question 8

What is the effect of dipyridamole?

Answer 8

Coronary vasodilatation

Question 9

What is the indication for Ciostazol?

Answer 9

Management of intermittent claudication

Question 10

What are the drugs that inhibit GPIIb/IIIa receptors?

Answer 10

Tirofiban
Eptifibatide
Abciximab

Question 11

What is the risk with aspirin resistance?

Answer 11

May cause recurrent ischemic vascular events in patients taking low dose aspirin

Question 12

What is the mechanism of action of clopidogrel?

Answer 12

Selective inhibition of the ADP receptor, leading to inhibition of platelet aggregation

Question 13

Describe the population variation of clopidogrel and prasugrel

Answer 13

Prasugrel has less population variation than clopidogrel. A significant portion of the population is non-respondant to clopidogrel due to a polymorphism.

Question 14

Is antiplatelet monotherapy typically used?

Answer 14

No, dual antiplatelet therapy is often used because single target therapy is not sufficient.

Question 15

What are the clinical applications of antiplatelet drugs?

Answer 15

Cerebrovascular disease (TIA, stroke)
Coronary artery disease (MI, unstable angina)
Saphenous vein coronary artery bypass grafts
Peripheral vascular disease
Small vessel disease
Prevention of thrombosis on artificial surfaces

Question 16

What drugs interact with anti-platelet drugs?

Answer 16

Thrombolytic agents
Heparin/LMW heparin/Oral anticoagulants
Warfarin
Antithrombin agents

Question 17

What are the two pathways of arachadonic acid metabolism?

Answer 17

Cyclooxygenase pathway to form PGs

Lipoxygenase pathway to form LTs

Question 18

What are the main regulators of prostacyclin and thromboxane synthesis?

Answer 18

Endothelial lining
Lipoproteins and other blood components
Diet, drugs, hemodynamics

Question 19

Describe the balance between PGI2 and TXA2 and how it is modulated

Answer 19

Healthy individuals should COX pathways that favor PGI2 over TXA2 in order to prevent clotting.

Aspirin blocks TXA2 formation in order to tip the balance in favor of PGI2

Question 20

Describe the pharmacology of omega 3 fatty acid

Answer 20

Contains acids that compete with AA in the PG pathway in order to inhibit the effects of TXA2

Question 21

Which antiplatelet drugs must be given via IV?

Answer 21

The GP IIb/IIIa inhibitors are the only antiplatelet drugs not given orally

Question 22

What is the mechanism of action of dipyridamole and cilostazol?

Answer 22

Phosphodiesterase inhibitors

Question 23

What are the eicosanoids?

Answer 23

Monteleukast
Zafirleukast
Zieuton

Question 24

What is the mechanism of action of monteleukast and zafirleukast?

Answer 24

Leukotriene receptor inhibitors

Question 25

What is the main side effect of the eicosanoids?

Answer 25

Hypotension

Question 26

What antiplatelet drugs are used to treat asthma?

Answer 26

Zafirleukast and Zieuton

Treatment for “aZZma”