Sketchy Pharm: Antiplatelet Agents

Question 1

What two molecules are exposed when endothelium is damaged?

Answer 1

Collagen and Von Willebrand factor (which binds to collagen)

Question 2

What platelet receptor binds to Von Willebrand factor?

Answer 2

GPIB (just like the 1 Bat being passed right in front of the damaged wall behind home plate)

Question 3

What molecule binds to the P2-Y12 receptor to activate platelet aggregation?

Answer 3

ADP (think of the aggregated players in front of the “Aggregate Da Players” sign, which has the Players Youth 2-12 league notice)

Question 4

Other than ADP, there are two molecules that also stimulate platelet aggregation: _______________.

Answer 4

serotonin (think of the player throwing his smiley-face helmet down) and thromboxane A2

Question 5

True or false: the constitutively expressed molecule thromboxane comes from COX-2.

Answer 5

False. It is constitutively expressed by COX-1.

Question 6

In addition to stimulating platelet aggregation, thromboxane A2 also ____________.

Answer 6

serves to constrict the arteries

Question 7

How does aspirin irreversibly inhibit the COX enzymes?

Answer 7

It adds an acetyl group (just like the acetyl whistle that the umpire is wearing as he throws Couch Cox out of the game).

Question 8

The -grel drugs work by ________________.

Answer 8

irreversibly blocking the ADP receptor (just like the guy with the hot doG GRiLl who is leaning over to catch the ball that would normally go to the players aggregating by the ADP sign –he’s gonna take that ball home, so it’s definitely permanent)

Question 9

What causes aspirin allergy?

Answer 9

Unopposed leukotriene synthesis (think of this effect by the ASA umpire is red in the face)

Question 10

What is a common indication for thienopyridine use?

Answer 10

Peripheral artery disease or MI prevention in someone allergic to aspirin

Question 11

What is dual-antiplatelet therapy?

Answer 11

Aspirin combined with a P2-Y12 antagonist –commonly used with stent thrombosis prevention (think of the corked bat above Couch Cox)

Question 12

Which thienopyridine has a risk of agranulocytosis?

Answer 12

Ticlodipine (just like the guy wearing the Ty CLobb) shirt next to the hot Dog GRiLls holding the hourglass)

Question 13

What is the mechanism of GPIIb/IIIa receptor antagonists?

Answer 13

GPIIb/IIIa is a platelet receptor that binds to fibrin. When many platelets bind to fibrin, a plug is formed. Thus, blocking this receptor prevents plug formation.

Question 14

What are the GPIIb/IIIa antagonists?

Answer 14

Abciximab (just like the Athletic Broadcasting Company ordering all the fibrinogen fries)

Eptifibatide (it has FIB in the name because it prevents binding to fibrin, and the TIED scoreboard should help you associate it with abciximab)

Tirofiban (just like eptifibatide, it has FIB and TIED in the name)

Question 15

What test is used to monitor potential overdose of abciximab, ticlodipine, and ASA?

Answer 15

Bleeding time (which is only used for platelet function)

Question 16

What phosphodiesterase inhibitors are used in the prevention of platelet aggregation?

Answer 16

Dipyramidole and cilostazol (think of (1) the two pyramids above the sign for kids to sign up for cAMP and (2) the boy who LOST the ball –lost-the-ball = cilostazol)

Question 17

How does decreased cAMP prevent platelet aggregation?

Answer 17

Decreased cAMP leads to decreased PKA activity which decreases platelet ability to activate

Question 18

What is coronary steal syndrome?

Answer 18

If you have stenotic coronary vessels, then the parts distal to the stenosis are likely dilated to their maximum. Giving a vasodilator (like cilostazol –with the boy’s dilated sleeves) will only dilated the other, non-coronary vessels which will pull blood away from the coronary system.

Question 19

The main side effect of the GPIIb/IIIa inhibitors is ______________.

Answer 19

thrombocytopenia (like the broken plates next to the fry salesmen)

Question 20

True or false: you could use abciximab on someone with Glanzmann thromasthenia.

Answer 20

False. GT is an autosomal recessive defect in GPIIb/IIIa, so abciximab would do nothing.

Question 21

Those with Bernard-Soulier have a defect in which protein?

Answer 21

GPIb (like Von Bill Clinton who was full of BS)