Thrombosis Flashcards
How does unfractionated heparin work?
Binds antithrombin
Potentiating formation of antithrombin-coagulation factor complex(Xa and IIa)
What indirect thrombin inhibitor can be given to avoid HIT?
Fondaparinux
What is the mechanism for Fondaparinux?
Synthetic polysaccharide that binds active site of antithrombin, inhibits Xa
What is the mechanism of LMWH?
Same as unfractionated heparin except, they inhibit thrombin less effectively
What are the LMWH?
Dalteparin
Enoxaparin
Tinzaparin
The effects of indirect thrombin inhibitors can be reversed with?
Protamine
Exception is Fondaparinux
What is one of the advantages of LMWH?
Longer half-life than heparin
What is the target value for PTT?
2-2.5x normal value
What are the indirect thrombin inhibitors?
Unfractionated heparin Dalteparin Enoxaparin Tinzaparin Fondaparinux
What drug class in warfarin?
Vitamin K antagonist
What is the mechanism for warfarin?
Blocks vitamin K-dependent gamma carboxylation of factors II, VII, IX, X, Protein C & S
(does not affect already synthesized factors)
What is the therapeutic use of warfarin?
Long-term anticoagulation
Why must you use heparin with warfarin therapy?
Thrombosis(protein C depression) –> skin necrosis –> use heparin
Warfarin is monitored by?
PT/INR
Why is warfarin contraindicated in pregnancy?
Because warfarin is a teratogen
Barbiturates are contraindicated with warfarin therapy because?
They enhance metabolism of induce P450, this leads to a lower PT.
What are the direct thrombin inhibitors?
BAD Bivalirudin Argatroban Dabigatran They don't require antithrombin III to work
How do the direct thrombin inhibitors work?
Inactivate fibrinogen-bound and unbound thrombin
Irreversible(Bivalirudin)
Reversible(Dabigatran)
Which direct thrombin inhibitor doesn’t require PT or INR? And why?
Dabigatran
Renal fixed dose clearance
What is Dabigatran used to treat?
DVT
PE
Atrial fibrillation
What are Bivalirudin and Argatroban used to treat?
Percutaneous coronary intervention
Which direct thrombin inhibitor can be used to avoid HIT?
Argatroban
Name the direct Xa inhibitor?
RivaroXAban
ApiXAban
What is the mechanism for direct Xa inhibitors?
Reversible bind active site of Xa
What do direct Xa treat?
DVT/PE prophylaxis
Name the fibrionolytic?
-PLASE lyse those clots
Alteplase(TPA)
Reteplase
Tenecteplase
How do fibrinolytics work?
They lyse already formed clots by activating circulating plasminogen
What are fibrinolytics used to treat?
Acute MI
Acute stroke
Multiple PE
Central DVT
What are the antiplatelets drugs?
Aspirin Dipyridamole Clopidogrel Abciximab Eptifibatide Tirofiban
What is the mechanism of EptiFIBatide and TiroFIBan(antiplatelet)
Fibrinogen analog which competes with endogenous fibrinogen for IIb/IIIa
What is the mechanism of abciximab?
Monoclonal antibody against GpIIb/IIIa
What is the mechanism of Clopidogrel?
Inhibits platelet ADP receptors
What is the mechanism of Dipyridamole?
PDE inhibitor –> increase platelet cAMP
Clopidogrel and aspirin are used to prevent & treat?
MI
ACS
Stroke
How can you reverse the effect of clopidogrel?
Platelet transfusion
