Antiplatelet Drugs

Question 1

What processes do antiplatelet drugs target?

Answer 1

1) primary hemostatic plug formation
2) aggregation
3) activation
4) release mechanisms

Question 2

How is a platelet aggregation assay performed?

Answer 2

1) prepare PRP
2) activate platelets
3) measure light transmittance

light goes thru –> aggregation
no light thru –> no agg

Question 3

What 3 things are released by light granules?

Answer 3

1) platelet factor 4
2) beta thromboglobulin
3) platelet derived growth factor (PDGF)

Question 4

What 3 things are released by dark granules?

Answer 4

1) Ca++
2) Serotonin
3) ATP/ADP

Question 5

What products are formed during platelet activation and endothelial interaction?

Answer 5

prostaglandin derivatives
endoperoxides
thromboxanes

Question 6

Why is there a specific niche for antiplatelet agents that cannot be covered by heparin and oral anticoags?

Answer 6

antiplatelet drugs act in arterial circulation

Question 7

What are antiplatelet drugs used for?

Answer 7

primary and secondary prevention of thrombotic cerebrovascular/cardiovasc diseases

Question 8

Name the 4 classes of antiplatelet agents

Answer 8

1) Aspirin - decreased platelet agg
2) COX inhibitors
3) propionic acid derivatives (ibuprofen, naproxen)
4) ADP receptor inhibitors

Question 9

What are the ADP receptor inhibitors?

Answer 9

Ticlopidine
Clopidogrel
Prasugrel
Ticagrelor
Cangrelor

Question 10

True or false: all ADP receptor inhibitors are prodrugs and require transformation into active forms in the liver

Answer 10

TRUE (except for ticagrelor)

Question 11

What is the primary function of antiplatelet drugs?

Answer 11

to decrease platelet aggregation in the arterial system

Question 12

What drug is used for the management of intermittent claudication?

Answer 12

cilostazol

Question 13

Every patient undergoing open heart surgery takes ________ because it is a coronary vasodilator

Answer 13

dipyridamole

Question 14

What are the GP2b/3a inhibitors?

Answer 14

abciximab
tirofiban
eptifabatide

Question 15

What likely causes aspirin resistance?

Answer 15

COX polymorphism

Question 16

How does Clopidogrel act?

Answer 16

blocks ADP receptor so ADP cannot bind to the platelet and recruit more platelets

Question 17

If a patient is not responding to clopidogrel, what do you do?

Answer 17

Give prasugrel

Question 18

What is involved in dual antiplatelet therapy?

Answer 18

aspirin/ADP receptor inhibitors or GP2b/3a inhibitors or dipyridamole

Question 19

What is involved in triple antiplatelet therapy?

Answer 19

aspirin/ADP receptor inhjbitor/cilostazol

Question 20

what are the top 2 clinical applications of antiplatelet drugs?

Answer 20

1) Cerebrovascular disease (transient ischemic attack, complete stroke)
2) Cardiovascular disease (acute MI, unstable angina)

(also CABG, peripheral vascular disease)

Question 21

True or false: drug interactions are minimal with antiplatelet drugs

Answer 21

FALSE they are profound (urokinase, streptokinase and tPA)

Question 22

What are the 2 pathways arachidonic acid is metabolized?

Answer 22

1) COX (into prostaglandins)

2) lipoxygenase (leukotrienes)

Question 23

What is the main mechanism by which aspirin mediates its therapeutic effects?

Answer 23

inhibits thromboxane formation in platelets

Question 24

What is an inhibitor of the lipoxygenase pathway?

Answer 24

zileuton (used to treat asthma)

Question 25

What are 2 leutotriene antagonists?

Answer 25

1) montelkast (asthma/allergies) | 2) zarirlukast (asthma)

Question 26

What exsmye is responsible for the formation of arachidonic acid?

Answer 26

phospholipase A2

Question 27

True or false: fish oil has antiplatelet action

Answer 27

TRUE (forms inactive TXA2)