Antiplatelets And Anticoagulants

Question 1

In absence of vascular injury, these keep platelets from aggregating released by endothelium

Answer 1

NO - dilates blood vessel

Prostacyclin - binds to platelet receptors to prevent aggregation

Question 2

Platelets adhere to exposed collagen via

Answer 2

von Willebrand Factor

Question 3

Activated irregularly shaped platelets secrete granules that attract and activate even more platelets to site of injury

Answer 3

Platelet activating factor
ADP
Thrombin 
TXA2
Serotonin

Question 4

Platelet receptor that binds to circulating fibrinogen

Fibrinogen binds to two separate platelets that form aggregates

Answer 4

GPIIb/IIIa

Question 5

Platelet activation leads to formation of TXA2 from activation of arachidonic acid by COX -> PGH2 -> TXA2

Irreversibly inactivates COX1 enzyme thus effectively disruptiong clot formation

Answer 5

Aspirin

Question 6

Blocks action of the ADP receptor P2Y12 subtype on PLATELET

Prevents binding of ADP to P2Y12 receptor leading to inactivation of GPIIb/IIIa receptors that bind to fibrinogen to promote cross-linking

Answer 6

ADP P2Y12 inhibitors

Clopidogrel
Prasugrel
Ticagrelor
Ticlodipine

Question 7

Blocks GPIIb/IIIa receptors on PLATELET so it will not bind to fibrinogen and will not cross link

Administered only IV

Answer 7

Abciximab
Eptifibatide
Tirofiban

Question 8

Phosphodiesterase inhibitors responsible for breaking down cyclic AMP to AMP

Blocking phosphodiesterase
INC intracellular levels of cAMP
DEC intracellular Calcium
Inhibition of platelet activation

Answer 8

PDE inhibitors

Dipyridamole
Cilostazol

Question 9

Also inhibits PDE in the vascular wall and
Inhibits uptake of adenosine leading to VASODILATION

Hence used for PAD (narrowing of vessel)

Answer 9

Cilostazol

SE: headache

Question 10

Antiplatelets

Answer 10

Aspirin
ADP P2Y12 inhibitors (Clopid, Prasu, Ticlodipine, Ticagrelor)
GPIIb/IIIa inhibitors (Abciximab, Eptifibatide, Tirofiban)
PDE inhibitors (Cilostazol, Dipyridamole)

SE: bleeding, headache

Question 11

Binds to Anti thrombin III to inactivate Factor Xa and Thrombin

Accelerates Anti thrombin III

Answer 11

Heparin

Question 12

Selectively accelerate inactivation of Factor Xa

Answer 12

Low molecular weight heparin

Enoxaparin
Dalterparin

Question 13

No direct effect on thrombin

Selectively binds to Anti thrombin III thereby inhibiting factor Xa ONLY

Related to LMWH

Answer 13

Fondaparinux

Question 14

Binding to heparin or LMWH to form stable inactive complex

Reverses excessive bleeding caused by heparin drugs

Answer 14

Protamine sulfate

Question 15

Heparin SE

Antibodies made against heparin when it is bound to platelet derived protein called Platelet Factor-4

Platelets clump together form unwanted clots

Answer 15

Heparin-induced thrombocytopenia

Question 16

Direct inhibitors of Factor Xa

Bind directly to active site of Factor Xa preventing it from converting

Prothrombin -> Thrombin

Oral

Answer 16

Apixaban

Rivaroxaban

Question 17

Direct thrombin inhibitors

Answer 17

Univalent direct thrombin inhibitors (bind only to active site)
Bivalent Direct thrombin inhibitors (both active site and exosite-1 fibrinogen binding site)

Question 18

Univalent Direct Antithrombin drugs

Answer 18

Argatobran

Dabigatran

Question 19

Bivalent direct antithrombin

Answer 19

Bivalirudin

Desirudin

Question 20

Direct antithrombin inhibitors are useful in treatment of heparin induced thrombocytopenia because they do not bind to

Answer 20

PA F4

Question 21

Decreases Vitamin K that carboxylases Factors 1972

Inhibits Vitamin K epoxide reductase disrupting Vitamin K dependent synthesis of coagulating factors

Narrow therapeutic windows
Many drug-drug interactions

Monitor with PT and INR

Answer 21

Warfarin

Question 22

Overcomes Warfarin induced bleeding but takes 24 hours

Answer 22

Vitamin K

If emergency transfuse FFP

Question 23

Act on existing clot causing it to dissolve by activating Plasminogen turning them into plasmin

Plasmin is the enzyme that breaks fibrin molecules dissolving clot

SELECTIVE to FIBRIN BOUND PLASMINOGEN, CLOT SELECTIVE DISSOLVES FIBRIN IN THROMBUS

Developed by DNA recombinant technology to mimic TPA

Answer 23

Alteplase
Reteplase
Tenecteplase

Question 24

Thrombolytic produced from culture human kidney cell

Less clot selective and are more likely to cause internal bleeding into any organ system

Answer 24

Urokinase

Question 25

Thrombolytic from streptococcal bacteria

Less clot selective and are more likely to cause internal bleeding into any organ system

Answer 25

Streptokinase

Question 26

Antidote to thrombolytic bleeding

Inhibits plasminogen so plasmin will inactivate fibrinolysis

Answer 26

Aminocaproic acid

Tranexamic acid