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9 Cards in this Set
- Front
- Back
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Where is Heparin found? |
Naturally occurring in liver, lungs and mast cells |
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What is the heparin family ? |
A family of sulphated muco-polysaccharides Sulphated give high -ve charge Come in a range of MW 3-40K Varying structures: Standard, unfractionated |
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Consequences of differing molecular structures of heparin ? |
Different sizes have different functions They can be separated out, applied differently |
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Problems with Heparin? |
Poorly absorbed from oral administration Due to large size of heparin molecules, and its charge Has to be given IV or subcutaneously Risk of Haemorrhage Common to all anticoagulants Mild case: Cease dosage Severe case: Complex Heparin with Protamine, Protamine has a +ve charge Charges bind, clumps with Heparin, unable to be used by body |
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Action of Heparin |
Inhibits action of Thrombin, and Factors X, IX |
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For Heparin action, what needs to be present? |
Antithrombin III (ATIII) ATIII is a protease inhibitor Normally it opposes coagulation |
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Mechanism of Heparin action? |
hepatin binds to both ATIII and thrombin, Forms an inactive Thrombin complex |
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Effect of Thrombin innactivation? |
Thrombin converts Fibrinogen to Fibrin, Stopping this prevents formation of fibrin mesh, making clot less stable |
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Advantages of Low Molecular Weight Heparin? |
LMW Heparin acts faster, and its effects last longer They can only effect factor Xa, not Thrombin |
