L25

Question 1

What are the 2 most potent factors to upregulate GP2b3a receptor for platelet aggregation and thrombus formation?

Answer 1

Thrombin

Collagen

Question 2

Aspirin mechanism

Answer 2

COX inhibitor
X TXA2 synthesis - no platelet aggregation
Permanently inhibits that platelet - must wait for liver to make more
“Weak” anti-platelet

Question 3

Aspirin:

• Dose dep inhibition?
• When does drug become bioavail
• t1/2

Answer 3

Dose dep inhibition of COX
Works in pre-hepatic circulation after GI absorption
- Drug doesn’t need to reach systemic circulation
t1/2 doesn’t really matter - matters how long it takes to make new platelets

Question 4

3 times to use aspirin

Answer 4

Can take 81mg daily to prevent a 1st CV event - really only for high risk pts (stable angina)

1. ↓MI mortality - chew baby aspirin when you have chest pain!
2. CABG graft patency, stents
3. Prior stroke to ↓risk another

Question 5

SE aspirin

Answer 5

Could be allergy

GI

Question 6

What is the mechanism of aspirin resistance?

Answer 6

TXA made b/c platelets express COX2
Dx by ↑TXA in urine
These pts have baseline ↑risk MI, stroke, etc

Question 7

Dipyridamole mechanism

Answer 7

cAMP phosphodiesterase inhibitor on platelets
X TXA2
Not 1st line choice

Question 8

What are the 3 ADP receptor antagonists? Which is already in active form?

Answer 8

Clopidogrel - 2 time cyp2C19 activation
Prasugrel - 1 time “ “
Ticagrelor - active form

Question 9

Mechanism of ADP receptor antagonists

Answer 9

X ADP receptor binding
- No ADP - P2Y12 binding
No Gp2b3a receptor upregulation for platelet aggregation

Question 10

Action of ADP receptor antagonists - which is an important extra

Answer 10

Uses: prevent re-events
↓stent thrombosis
↓N/STEMI recurrence
**TICAGRELOR ↓s CV DEATH RATE

Question 11

What is standard ADP receptor antagonist therapy?

Answer 11

Dual anti-platelet therapy

X + aspirin

Question 12

What should you consider when dosing prasugrel?

Answer 12

End stage renal disease - only get about 1/2 amt of active metabolite you’re exposed to

Question 13

3 situations in which to use prasugrel > clo

Answer 13

Cerebrovasc

Over 75 yo

Question 14

Pts w/ stents placed should be on what type of therapy

Answer 14

Anti-PLATELET for at least a year until stent has been fully endothelialized

Question 15

What are the 2 Gp2a3b receptor antagonists

Answer 15

Abciximab - irreversible

Eptifibatide

Question 16

What is the use of Gp2a3b receptor antagonists

Answer 16

Pre-PCI

Otherwise no benefit for routine use