anticoagulation drugs

Question 1

clopidogrel, ticlopidine mechanism and risks

Answer 1

irreversibly block ADP receptors (ADP is important for platelet adherence to the endothelium and the coagulation cascade) (also block fibrinogen binding by prenting glycoprotein IIB/IIIa from binding to fibrinogen but this is not emphasized)
can cause hemorrhage, GI bleeds, neutropenia with ticlopidine

Question 2

How does heparin work? How does LMWH work?

Answer 2

heparin bints to antithrombin to increase its activity and prevent clot formation. LMWH binds to factor Xa to prevent clot formation

Question 3

What are the 2 paths for anticoagulation in the body?

Answer 3

1. protein C and protein S work together to cleave and inactivate Va and VIIIa
2. Plasminogen is activated by tPA to become plasmin, which activates fibrinolysis (cleaves fibrin mesh and destroys coagulation factors)

Question 4

abciximab, tirofiban

Answer 4

GP IIb/IIIa inhibitors that prevent platelet aggregation. reduce the risk of thrombus in unstable angina or following coronary vessel intervention.
also eptifibatide

Question 5

What are the adenosine reuptake inhibitors and how the they work?

Answer 5

inhibit activity of adenosine deaminase and phosphodiesterase to increase cAMP and inhibit platelet aggregation. may be used in combo with ASA for stroke/heart valve replacement
aka dipyridamole, cilastazole

Question 6

What are the direct thrombin inhibitors?

Answer 6

lepirudin, argatroban, bivalirudin. these are the leech anticoagulants. can be used instead of heparin for pts with HIT. argatroban is ok in pts with renal failure

Question 7

What are the direct factor Xa inhibitors?

Answer 7

apixiban, rivaroxaban, fondaparinux.