Lecture 7 Antiplatelets

Question 1

what occurs first following endothelial damage?

Answer 1

transient vasoconstriction via neural stimulation reflex and endothelin released from damaged cell

Question 2

platelets bind to exposed collagen via _____ binding the ____ receptor

Answer 2

VWF;

Gp1B

Question 3

After binding VWF, platelets are actiavted and release what three substances ?

Answer 3

ADP, TXA2, 5HT

and Ca

Question 4

binding of ADP induces ____ expression at the platelet surface, which binds _____

Answer 4

Gp2b/3a; fibrinogen

Question 5

intact endothelial cells release ____ and ____ to increase blood flow and inhibit platelet aggregation

Answer 5

PGI2, NO

Question 6

what enzyme is responsible for synthesis of TXA2?

Answer 6

COX 1

Question 7

Aspirin (ASA)’s mechanism of action:

Answer 7

irreversibly inhibits COX1 and COX2 via acetylation

Question 8

at low doses, ASA preferentially inhibits ____, causing _____. at high doses, it inhibits ____.

Answer 8

COX 1, decreased TXA2 synth;

COX 2

Question 9

ASA’s effect on bleeding time? PT? aPTT?

Answer 9

increased bleeding time, no effect on PT or PTT

Question 10

side effects of ASA: ____ due to inhibition of COX 1,

Answer 10

gastric bleeding

Question 11

What is the name of the 2 types of ADP receptors? What general receptor class do they belong to?

Answer 11

P2Y1, P2Y12;

GPCR

Question 12

what is another name of the ADP receptor inhibitor class?

Answer 12

thienopyridines

Question 13

name the 4 ADP receptor inhibitors listed in FA

Answer 13

clopidrogel, ticlodipine, ticagrelor, prasugrel

Question 14

Prausgrel vs ticagrelor:
which is a pro-drug?
which binds irreversibly?
which binds to an allosteric site?

Answer 14

prasugrel,
prasugrel,
ticagrelor

Question 15

_____ may induce TTP by inducing antibodies against what protease?

Answer 15

ticlodipine, ADAMTS13

Question 16

what does ADAMTS13 usually do

Answer 16

cleaves circulating vWF

Question 17

ADP receptor inhibitors are generally used for ______ and _____

Answer 17

acute coronary syndromes, coronary stenting

Question 18

what is the newest drug mentioned in the notes that inhibits ADP receptors?

Answer 18

cangrelor

Question 19

name the 3 GP2b/3a receptor inhibitors

Answer 19

abciximab, tirofiban, eptifibatide

Question 20

which of the Gp2b3a inhibitors….

is a chimeric monoclonal Ab?
is administered IV due to short half life?

Answer 20

abciximab,

tirofiban and eptifibatide

Question 21

what are the two phosphodiesterase inhibitors?

Answer 21

dipyridamole, cilostazol

Question 22

PDE inhibitor mechanism:

increased cAMP opposes ____ signalling, causing decreased platelet aggregation. in addition, they cause general ____

Answer 22

P2Y12;

vasodilation

Question 23

the PDE inhibitors are used for intermittent ____, coronary _____, and angina prophylaxis

Answer 23

claudication;

vasodilation

Question 24

Vorapaxar and atopaxar are ______. they cause decresed release of ____ and prevent thrombin from activating platelets

Answer 24

protease activated receptor (PAR) inhibitors;

Ca

Question 25

vorapaxar and atopaxar inhibit PARs by what?

Answer 25

proteolytic cleavage

Question 26

what kind of half life does vorapaxar have? what is it used with to prevent thrombosis in patients with previous MI?

Answer 26

long (ie 3 to 4 days);

used with aspirin or clopidogrel