P2Y12 Inhibitor Dosing

Question 1

clopidogrel: reversible or irreversible?

Answer 1

irreversible

Question 2

prasugrel: reversible or irreversible?

Answer 2

irreversible

Question 3

ticagrelor: reversible or irreversible?

Answer 3

reversible

Question 4

clopidogrel: prodrug?

Answer 4

yes

Question 5

prasugrel: prodrug?

Answer 5

yes

Question 6

ticagrelor: prodrug?

Answer 6

no

Question 7

clopidogrel binding site?

Answer 7

ADP binding

Question 8

prasugrel binding site?

Answer 8

ADP binding

Question 9

ticagrelor binding site?

Answer 9

allosteric

Question 10

clopidogrel onset of action?

Answer 10

2-6 hours

Question 11

prasugrel onset of action?

Answer 11

30 minutes

Question 12

ticagrelor onset of action?

Answer 12

30 minutes

Question 13

clopidogrel loading dose?

Answer 13

600mg

Question 14

prasugrel loading dose?

Answer 14

60mg

Question 15

ticagrelor loading dose?

Answer 15

180mg

Question 16

clopidogrel metabolism?

Answer 16

converted by a 2 step process involving 2C19, patients can vary between being a fast or slow metabolizer so someone’s response to clopidogrel can vary

Question 17

prasugrel metabolism?

Answer 17

single step via multiple pathways

Question 18

ticagrelor metabolism?

Answer 18

3A4 primarily

Question 19

clopidogrel percentage of platelet inhibition?

Answer 19

3-40%

Question 20

prasugrel percentage of platelet inhibition?

Answer 20

60-70%

Question 21

ticagrelor percentage of platelet inihbition?

Answer 21

60-70%

Question 22

clopidogrel maintenance dose?

Answer 22

75mg daily

Question 23

prasugrel maintenance dose?

Answer 23

10mg daily (remember: only for PCI!!!)
5mg if pt is <60kg or >75 years old

Question 24

ticagrelor maintenance dose?

Answer 24

90mg BID for 12 months

60mg BID after 12 months

Question 25

how soon to discontinue clopidogrel before surgery?

Answer 25

5 days

Question 26

how soon to discontinue prasugrel before surgery?

Answer 26

7 days

Question 27

how soon to discontinue ticagrelor before surgery?

Answer 27

5 days

Question 28

interactions with clopidogrel

Answer 28

PPIs can decrease efficacy due to CYP2C19

Question 29

high on treatment platelet reactivity occurs with what P2Y12 inhibitor?

Answer 29

may occur in about 30% of patients on clopidogrel, it means that the platelets are still very active and clopidogrel isn’t inhibiting them (this hasn’t been shown to change clinical outcomes)

Question 30

contraindication of prasugrel

Answer 30

history of stroke or TIA.
if patient <60kg,
if patient is older than 75

Question 31

contraindication of ticagrelor

Answer 31

history of cerebral bleed and severe liver disease

Question 32

interactions with ticragelor

Answer 32

concomitant strong CYP3A4 inhibitors/inducers,

do not use with more than 100mg of aspirin (dose related dyspnea and bradyarrhythmias)

Question 33

cangrelor (Kengreal) MOA

Answer 33

reduces ADP induced platelet activation and aggregation by inhibiting the P2Y12 receptor

Question 34

cangrelor onset of action

Answer 34

within 2 minutes of bolus administration, normal platelet activity resumes within 60-90 minutes of discontinuation

Question 35

cangrelor indications

Answer 35

PCI to reduce the risk of MI, repeat coronary revascularization, and stent thrombosis

Question 36

how long to use a P2Y12 inhibitor for ACS?

Answer 36

preferably 1 year

Question 37

how long to use a P2Y12 inhibitor for a bare metal stent?

Answer 37

minimum 1 month (this is because it is a foreign body that platelets will stick to and could cause another clot. Bare metal stents take less time to endotheliazie than drug eluting stents)

Question 38

how long to use a P2Y12 inhibitor for a drug eluting stent?

Answer 38

minimum 3 months