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Phar 505 > Pharmacology of Antiplatelet Medications > Flashcards

Pharmacology of Antiplatelet Medications Flashcards

1
Q

What are the three functions of platelets

A

Platelet adhesion, Platelet activation, platelet aggregation

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2
Q

T/F: Platelet receptors usually have interactions with just injured endothelium

A

True

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3
Q

What are the two main receptors of platelet adhesion

A

Collagen via GPVI, vWF via GP1b

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4
Q

T/F: The collagen and Gp1B vW receptors are only used for platelet adhesion

A

False: The collagen and Gp1B vW receptors also aid in platelet activation along with platelet adhesion

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5
Q

What protein is a potent activator of platelets, what receptors do this

A

Thrombin, PAR 1 and PAR 4

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6
Q

Why are alpha-2 and beta-1 receptors on platelets leading to activation

A

There could possibly be a high catecholamine surge due to vascular injury promoting a coagulation state

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7
Q

What are platelet receptor agonist for other platelet receptors that cause activation of the platelet

A

ADP: P2Y12 and P2Y1 receptors, Serotonin: 5-HT2A receptor, Thrombixin: TPa and TPb receptor

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8
Q

What occurs once the platelet is activated

A

The platelet will undergo a conformational change that exposes GP2b/3A receptor

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9
Q

How does the exposure of GP2b/3A receptor and Fibrinogen receptor lead to aggregation

A

The receptors bind to fibrinogen molecules also bound to GP2b/3A receptors causing binding to other platelets forming a blood clot

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10
Q

What is the average life span of circulating platelets

A

5 to 9 days

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11
Q

What leads to thrombus formation

A

Clotting cascade turns fibrinogen to fibrin clot

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12
Q

T/F: Aspirin is the best antiplatelet medication becuase it can be used for primary and secondary prevention of many different events

A

True

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13
Q

What is the common antiplatelet drug class used aside from Aspirin, what is the most common medication in the drug class

A

P2Y12 inhibitors, Clopidogrel

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14
Q

What are the P2Y12 inhibitor drugs besides clopidogrel, what are they usually used for, which only has one indication

A

Prasugrel, Ticagrelor, Cangrelor/ Secondary prevention of acute coronary syndrome and vascular procedure/ Cangrelor is only indicated for vascular procedure and not other secondary preventions

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15
Q

What are the GP2A/3b inhibitor drugs, what are they indicated for

A

Abciximab, Eptifibatide, Tirofiban/ Secondary prevention of acute coronary syndrome and vascular procedure

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16
Q

T/F: GP2A/3b inhibitor drugs can be taken on a monthly regimen

A

False: These drugs are only given IV and for vascular procedure

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17
Q

What are the phosphodiesterase inhibitors, which is used with Aspirin, for what indication

A

Dipyridamole and Cilostazol, Dipyridamole, Stroke and TIA

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18
Q

What causes prostaglandin H2 to be formed in the body

A

arachidonic Acid is converted by COX-1 and COX-2 into prostaglandin G2, prostaglandin G2 will be converted by peroxidase to Prostaglandin H2

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19
Q

What are the possible two most common lipids that prostaglandins are converted to, what enzymes does each conversion

A

Thrmoboxane A2 (TXA2)/ Thromboxane synthase, Prostacyclin (PGl2)/ Prostacyclin synthase

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20
Q

What are the functions of Thromboxane A2 (TXA2)

A

Vasoconstriction, Platelet activation and aggregation

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21
Q

What are the functions of Prostacyclin (PGl2)

A

Vasodilation, Inhibits platelet activation

22
Q

T/F:Prostaglandin H2 can cuase inflammation through formation into PGl2 as well as other prostaglandins

A

True

23
Q

How much aspirin is needed to inhibit COX-1

A

50-325 mg/day

24
Q

What is the MOA of aspirin

A

Acetylates serine residue near active site of COX-1 and irreversibly inhibits TxA2 production for lifespan of platelet

25
Q

T/F: Giving more aspirin leads to more inhibition of platelet activity

A

False: Complete inactivation of COX-1 is with 75 mg/day and increasing more will not cause more effects

26
Q

How often does Aspirin resistance happen

A

1/4 of patients

27
Q

What are the proposed mechanisms for nonresponses to Aspirin

A

COX-1 changes and drug interactions with NSAIDs

28
Q

Which P2Y12 inhibitor is a prodrug, what enzymes cause metabolism

A

Clopidogrel, CYP219 twice

29
Q

T/F: Genetic polymorphism of CYP12 can effect how well clopidogrel works and mostly effects Asians

A

True

30
Q

Which PY12 inhibitor is first metabolized by esterases in the blood stream and CYP12

A

Prasugrel

31
Q

Which PY12 inhibitors are drugs as soon as they are in the body

A

Ticagrelor

32
Q

T/F: Clopidogrel is a better platelet inhibitor than prasugrel

A

False: Prasugrel cause 90% platelet effect compared to Clopidogrel reaching peak effect at 60%

33
Q

T/F: Clopidogrel can reach its max platelet inhibition sooner if the loading dose is increased

A

True

34
Q

What is the max platelet aggregation for Ticagrelor

A

90%

35
Q

Why is the peak effect of Clopidogrel delayed compared to the newer genrations

A

It needs conversion by the liver to be effective

36
Q

Which PY12 inhibitor is IV

A

Cangrelor

37
Q

What is the dose of Ticagelor

A

180mg/90mg BID

38
Q

What drugs do Ticagelor interat with

A

Strong CYP3A4 inhibitors and inducers

39
Q

T/F: Clopidogrel and Prasugrel have irreversible receptor binding last at least 3 to 10 days

A

True

40
Q

T/F: GP2A/3B receptors can be around 50K to 100K on platelets andare prime targets for antithrombosis

A

True

41
Q

What are the GP2A/3B inhibitor medications

A

Abciximab, Eptifibatide, Tirofiban

42
Q

What is the duration of action of abciximab, eptifibatide, tirofiban

A

two days, 2-4 hours, 3-4 hours

43
Q

Which of the GP2A/3B inhibitors are renally eliminated

A

Eptifibatide and Tiofiban

44
Q

What happens intracellularly when ADP binds to the P2Y12 and P2Y1 receptors causing regulation of platlet activation

A

Adynlate cyclase converts ATP and GTP into cAMP and cGMP leading to decreased platelet activation

45
Q

How do phospodiesterases cause increase platelet activation

A

Decreases cAMP and cGMP by converting them to AMP and GMP

46
Q

What are the phosphodiesterase inhibitors

A

dipyridamole and cilostazol

47
Q

What is a huge antiplatelet adverse reaction

A

bleeding (gastrointesitnal, intracranial, vascular access sites)

48
Q

What antiplatelet drug class have the highest incidence of thrombocytopenia, which particular one needs the most caution

A

GP 2b/3a inhibitors, Abciximab

49
Q

T/F: Clopidogrel can cause thrombotic thrombocytopenia pupura (TTP)

A

True

50
Q

T/F: Ticagrelor can cause ventricular pause and Ticlopidne can cause myelosuppresion

A

True

Phar 505 (33 decks)

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