Antiplatelets

Question 1

What are antiplatelet drug uses

Answer 1

• since arterial clots are primarily made up of a platelet core, antiplatelet agents are primarily used to prevent arterial clots

Question 2

Which of the antiplatelet drugs have similar function

Answer 2

1) aspirin (cox inhibitor), P2Y12 inhibitors, and other miscellaneous antiplatelets drugs affect only one pathway in platelet activation
2) GP IIb/IIIa inhibitors block the final common step in platelet activation and thus are much more potent antiplatelets

Question 3

Aspirin indications

Answer 3

1) ischemic stroke
2) . TIA
3) chronic stable angina
4) unstable agnina
5) coronary stenting
6) acute myocardial infarction

Question 4

aspirin moa

Answer 4

• irreversible inhibition of COX

- decreases thromboxane a2 production thus reduces platelet activation

Question 5

contradictions to aspirin

Answer 5

use in children and teens with viral infections (reyes syndrome)

Question 6

ADR of aspirin

Answer 6

1) GI bleeds

2) hemorrhagic stroke

Question 7

Clopidogrel (Plavix) indications:

Answer 7

1) acute coronary syndrome (STEMI and NSTEMI)
2) ischemic stroke
3) peripheral atherosclerotic disease

Question 8

US box warning: Clopidogrel (Plavix)

Answer 8

diminished effects in CYP2C19 poor metabolizers

Question 9

MOA Clopidogrel (Plavix)

Answer 9

irreversibly blocks P2Y12 component of ADP receptors on the platelet surface- effects last the duration of the platelet’s life (7-10 days)

Question 10

Contraindications of Clopidogrel (Plavix)

Answer 10

Active pathological bleeding (peptic ulcer, intracranial hemorrhage)

Question 11

Dosage for aspirin

Answer 11

1) 81 mg- maximal effects on platelet function

2) 325 mg- indicated in initial treatment of an acute event (chew 4 aspirin)

Question 12

ADR of Clopidogrel (Plavix)

Answer 12

Bleeding

Question 13

Metabolism/excretion of Clopidogrel (Plavix)

Answer 13

1) must be metabolized by CYP2C19 into active drug
2) CYP2C19 is inhibited by. PPI (drugs used to reduce stomach acid and protect the stomach from GI bleeding)
3) american college of cardiology, aha, etc. issued a consensus document that PPIs may reduce the antiplatelet effects but NOT diminish the effects

Question 14

Prasugrel indications

Answer 14

Acute coronary syndrome

• slightly more effective than clopidogrel- BUT also had a higher risk of major bleeding
• bleeding significantly is increased in patients undergoing a CABG
• may also increase the risk of cancer

Question 15

DRUG INTERACTIONS OF CLOPIDOGREL

Answer 15

• PPIs are used to reduce stomach acid production and to protect the stomach from GI bleeding. But, the 2c19 it inhibited by ppis.
• however, we found out that ppis might reduce the antiplatelet effect but not enough to diminish the effects

Question 16

Prasugrel MOA

Answer 16

irreversibly blocks P2Y12. component of ADP receptors on the platelet surface- effects last the duration of the platelets life (7-10. days)

Question 17

Prasugrel contradictions

Answer 17

active pathological bleeding (peptic ulcer, intracranial hemmorhage) prior TIA or stroke

Question 18

ADR Prasugrel

Answer 18

Bleeding

Question 19

Prasugrel US box warning

Answer 19

Bleeding risk

1) significant sometimes fatal bleeding- avoid in patients with active pathological bleeding or a hx of TIA or stroke
2) in patients 75+ use is generally not recommended
3) do not use in patients likely need urgent CABG sx- d/c 7 day prior to sx (most agents are 5)
4) additional risk factors for bleeding, low body weight, propensity to bleed or hx of bleeding, concomitant medications that increase risk of bleeding
5) suspect bleeding in any patient who is hypotensive
6) IF POSSIBLE, MANAGE BLEEDING WITHOUT D/C PRASUGREL- D/C INCREASES THE RISK OF A SECONDARY EVENT

Question 20

Ticagrelor Indications

Answer 20

ACS, primary prevention of. ischemic cv events in CAD, minor ischemic stroke or high risk TIA
-more effective than clopidogrel (but fatal IC hemorrhage)

Question 21

US box warning ticagrelor

IMPORTANT

Answer 21

1) bleeding risk
2) ASPIRIN DOSES >100 MG CAN REDUCE THE EFFECTIVENESS OF TICAGRELOR AND SHOULD BE AVOIDED ( USE 81MG DOSE ASPIRIN INSTEAD)

Question 22

MOA of ticagrelor

Answer 22

reversible P2Y12 inhibition-reduces platelet aggregation

-inhibition of platelet aggregation is around 60% 24 hours after d/c of maintenance dosing

Question 23

contraindications of ticagrelor

Answer 23

active pathological bleeding or hx of ich

Question 24

ADR of ticagrelor

Answer 24

dyspnea

Question 25

cangrelor indications

Answer 25

used in patients who remain a high risk of thrombotic event and cannot tolerate a P2Y12 or at times used in cardiogenic shock

Question 26

cangrelor moa

Answer 26

Reversible P2Y12 inhibition- reduces platelet activation - activation in 2 minutes (ONLY IV AGENT) - total effects end about 1 hour after d/c - transition to p2y12 (stop cangrelor and immediately start oral agent)

Question 27

contradictions of cangrelor

Answer 27

signficant active bleeding

Question 28

ADR cangrelor

Answer 28

bleeding

Question 29

vorapaxar indications

Answer 29

history of MI or established peripheral artery disease | -reduce thrombotic event in combination with clopidogrel or aspirin (or both)

Question 30

vorapaxar MOA

Answer 30

PAR-1 antagonist- inhibit platelet aggregation

Question 31

contradictions of vorapaxar

Answer 31

hx of stroke, tia,ic hemm

Question 32

ADR vorapaxar

Answer 32

bleeding

Question 33

glycoprotein iib/iiia inhibitors

Answer 33

eptifibitide and tirofibam

Question 34

glycoprotein iib/iiia inhibitors indications

Answer 34

the most effective antiplatelet drugs - prevent ischemic events in those undergoing PCI- prevent re-occlusion following coronary artery revascularization with PCI- typically used on primary PCI facilities

Question 35

US box warnings: glycoprotein iib/iiia inhibitors

Answer 35

none

Question 36

glycoprotein iib/iiia inhibitors MOA

Answer 36

reversible blockade of GP iib/iiia receptors on platelets and thereby inhibit the final step of aggregation - prevent aggregation stimulated by all factors including collagen...

Question 37

contraindications: glycoprotein iib/iiia inhibitors

Answer 37

1) active abnormal bleeding within the previous 30 days or a hx of bleeding diathesis 2) hx of stroke within 30 days or hx of hemorrhagic stroke 3) severe HTN 4) major sx within the preceding 6 weeks

Question 38

dipyridamole/aspirin (aggrenox) indications

Answer 38

prevent. recurrent stroke or tia | - shown more effective than either drug alone - the clinical trial was tainted by scientific scandal

Question 39

dipyridamole/aspirin (aggrenox) us box warnings

Answer 39

none

Question 40

dipyridamole/aspirin (aggrenox) MOA

Answer 40

dipyridamole inhibits the uptake of adenosine into platelets- prevents platelet activation/ aggregation

Question 41

dipyridamole/aspirin (aggrenox) contradictions

Answer 41

same as aspirin

Question 42

route dipyridamole/aspirin (aggrenox)

Answer 42

oral capsules | - note: there is not enough aspirin for primary prevention of MI (ony 50mg and you need > 80 mg)