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21 Cards in this Set
- Front
- Back
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What are the indirect inhibitors of thrombin? Direct inhibitors?
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Indirect- heparin, LMWH, fondaparinux
Direct- bivalirudin, argatroban |
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What is the structure of heparin?
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Series of glucuronic acid and glucosamine modified by sulfate groups.
Large proteoglycan. |
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What is the mechanism of heparin?
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Binds to AT III, inducing a conformational change to expose the anti-protease site. AT III binds to thrombin and other factors to inactivate them.
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What are the advantages of LMWH?
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Longer half life
Less monitoring Lower incidences of adverse effects. |
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What does Fondaparinux do?
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Activates antithrombin only
Doesn't require monitoring. |
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What are the kinetics of heparin?
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Parental administration
1-2 hour half life, which is dose dependent. LMWH is dose-independent |
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What are the uses for heparin?
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Venous thrombosis and pulmonary embolism, administered with warfarin.
Cardiopulmonary bypass Catheter |
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What is the toxicity of heparin?
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Bleeding- treat with protamine sulfate
Heparin-induced thrombocytopenia Osteoporosis Aldosterone inhibition |
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What is the mechanism for Bivalirudin and Desirudin?
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Binds to thrombin at active site and blocks proteolytic activity.
Decreases interaction with fibrinogen. Treat HIT. |
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What is the mechanism for Argatroban?
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Binds to catalytic site of thrombin.
Treat HIT. |
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What is the mechanism for warfarin?
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Blocks reduction of vitamin K epoxide, which prevents the conversion of N-terminal residues from Glu to Gla in the production of Factors II, VII, IX and X.
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What are the kinetics of warfarin?
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GI
40 hours half life Plasma bound Inactivated by liver |
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What factors decrease effectiviness of warfarin?
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Cytochrome P450 inducers.
vitamin K rich foods |
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What are factors that increase effectiviness of warfarin?
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Displace warfarin from plasma proteins- phenylbutazone, sulfinpyrazone, metronidazole, allopurinol, cimetidine.
Decreased vitamin K- antibiotics |
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What is the toxicity for warfarin?
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Bleeding- administer vitamin K.
Birth defects |
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How does aspirin work as an antiplatelet?
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Inhibits COX, which produces a precursor of TXA2, which stimulates platelet aggregation.
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How do Ticlopidine and Clopidogrel work as antiplatelets?
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Antagonize P2Y12 receptor to block fibrinogen receptor acitivty and decrease platelet aggregation.
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What is the toxicity of antiplatelet drugs?
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N/V/D
Neutropenia Thrombocytopenia |
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What is the use of antiplatelet drugs?
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Phrophylactic
Prevention of CVA after stroke Treat MI with thrombolytics Use with aspirin during angioplasty and stent. |
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What is Abciximab?
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Fab fragment from monoclonal antibody against GPIIb/IIIa. Prevents platelet binding to fibrinogen or von Willebrand factor.
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What is the action of Eptifibatide and Tirofiban?
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GPIIb/IIIa inhibitors.
Not as effective as abciximab. |
