Nov23 M1-Pharmacology Antiplatelet Drugs

Question 1

3 drug groups

Answer 1

• inhibit Tx synthesis
• block ADP receptor
• inhibit glycoprotein IIB-IIIA

Question 2

use of anti-platelet drugs

Answer 2

prevent thrombosis

alter evolution of ats

Question 3

2 types of granules found in platelets

Answer 3

delta granules (contain ADP)
alpha granules

Question 4

mechanism of primary plug formation

Answer 4

1. plts recon vWF and collagen and are activate
2. activate plts release ADP, TxA2 and 5HT
3. these substances activate platelets and activate an integrin (glycoprot IIB-IIIA) on their surface
4. this integrin binds fibrinogen and fibrin
5. formation of formalin aggregate

Question 5

what happens to plts when activated

Answer 5

change shape and have processes

Question 6

aspirin action

Answer 6

blocks covalently (irreversibly) COX-1 (acetylates serine residue near its active site) so can’t produce TxA2

Question 7

why aspirin effect irreversible

Answer 7

platelet no nucleus, can’T prod new COX 1

Question 8

why ASA less effective at higher dose (NSAID dose)

Answer 8

Also inhibits prostacyclin prod (prostacyclin is an endogenous anti platelet)

Question 9

where ASA absorbed

Answer 9

stomach and upper SI

Question 10

ASA overdose effect

Answer 10

primary metab pathway saturated. elim becomes order 0 (constant rate no matter dose). significant increase in plasma ASA

Question 11

aspirin effect on bleeding time

Answer 11

prolonged in all patients

Question 12

salicylism def + cause

Answer 12

reduce hearing, ringing in ears, dizziness. cause: mild overdose.

Question 13

aspirin use

Answer 13

secondary prevention of cerebral and cardiac ischemia, MI, …

Question 14

inhibitors of ADP pathway mechanism

Answer 14

block ADP receptor on platelet surface

Question 15

inhibitors of ADP pathway: give drugs

Answer 15

clopidogrel, prasugrel, ticagrelor

Question 16

diff between inhibitors of ADP pathway and ASA

Answer 16

they have no effect on PG metabolism

Question 17

2 inhibitors of ADP pathway used and effect

Answer 17

clopidogrel, prasugrel. irreversibly block ADP receptor

Question 18

how ADP activates platelets

Answer 18

binds two purine receptors. P2Y1 and P2Y12. both must be activated

Question 19

clopidogrel effect

Answer 19

irreversibly blocks P2Y12 receptor

Question 20

clopidogrel pharmacokinetics

Answer 20

given as prodrug, activated by enzymes in cytochrome P450.

Question 21

why clopidogrel resistance exists

Answer 21

genetic variability. some patients have reduced fct variant of CYP2C19 enzyme of the cytochrome P450

Question 22

when clopidogrel used with ASA and when used instead of ASA

Answer 22

clopidogrel in stroke

clopidogrel with aspirin in ACS (acute coronary syndrome)

Question 23

prasugrel effect + diff with clopidogrel

Answer 23

same effect. P2Y12 blocker irreversibly.

less resistance to it

Question 24

ticagrelor mechanism

Answer 24

blocks REVERSIBLY P2Y12

Question 25

ticagrelor when

Answer 25

in ACS, to reduce CV death, MI and stroke (better than clopidogrel)

Question 26

glycoprot IIB-IIIA fct

Answer 26

receptor fo fibrinogen and vWF

Question 27

glycoprot IIB-IIIA inhibitors: potency and administration

Answer 27

best anti plt but replaced by ticagrelor and prasugrel | given by injection

Question 28

abciximab charact and mechanism

Answer 28

Fab fragment of humanize monoclonal Ab against the receptor

Question 29

eptifibatide and tirofiban mechanism

Answer 29

peptide (2nd is small molecule) blocker of fibrinogen binding site on the receptor

Question 30

major side effect of glycoprot IIB-IIIA inhibitors

Answer 30

bleeding and thrombocytopenia

Question 31

arterial vs venous side choice of medication

Answer 31

arterial side: anti platelet drug

Question 32

which for stroke

Answer 32

``` anti platelet (clopidogrel) dabigatran ```

Question 33

which for DVT

Answer 33

UF heparin and then warfarin | LMWH heparin if good kidney function and then warfarin

Question 34

which prevention of cereb or cardiac and ischemia + MI

Answer 34

aspirin

Question 35

which to prevent stroke if prosthetic heart valve or mitral stenosis

Answer 35

warfarin

Question 36

which to prevent stroke in a fib

Answer 36

rivaroxaban

Question 37

which for 6 hours after after acute STEMI

Answer 37

alteplase or tenecteplase