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18 Cards in this Set
- Front
- Back
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main anticoagulants
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-heparin
-warfarin -new - dabigitran exilate, rivaroxiban |
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tell me about these bad boys, include ACTION, ADMINISTRATION, USES, SIDE EFFECTS
-heparin... -warfarin -new - dabigitran exilate, rivaroxiban |
HEPARIN
ACTION -binds to and enhances the action of the endogenous anticoagulant ANTITHROMBIN III (a protease inhibitor circulating in the plasma) -HEPARIN-ANTITHROMBIN III COMPLEX binds to and inhibits the action of clotting factors IIa, IXa, Xa, XIa, XII -immediate inhibition of clotting -LMWH inhibits only factor Xa - giving it more conistent effects ADMINISTRATION -not orally active (absorption prevented by high MW and -ve charged sulphate residues) -IV or subcut -does not cross blood-brain barrier or placenta USES -DVT treatment (does not reduce DVT size but stops it growing) -PE treatment -safe in pregnancy SIDE EFFECTS -allergy -haemorrhage -side effects reversed by PROTAMINE - polycationic protein binds to heparin (-ve sulphate residues) and inactivates it |
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tell me about these bad boys, include ACTION, ADMINISTRATION, USES, SIDE EFFECTS, ISSUES
-heparin -warfarin... -new - dabigitran exilate, rivaroxiban |
WARFARIN
ACTION -REDUCED VIT K is essential for CARBOXYLATION OF factors II, VII, IX, X -warfarin blocks VIT K REDUCTASE, thereby preventing carobylation of these factors, meaning they can no longer bind with Ca++, no COAGULATION -delayed effect (takes 3 days for dysfunctinoal factors to replace functional ones) -cr -NOT active in vitro. obviously. ADMINISTRATION -orally active -99% bound to albumin (released by ASPIRIN) -crosses blood/brain barrier and placenta USES -venous thrombosis -to prevent TPE -to prevent embolism in AF -prophylaxis following valve replacement SIDE EFFECTS -haemorrhage -reverse with plasma or clotting factor concentrates, oral vit K (slow) ISSUES -difficult to get optimal dose - albumin binding, accumulation in adipose tissue -monitoring of INR (usually 2.0 - 3.0) |
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tell me about these bad boys, include ACTION, ADMINISTRATION and USES
-heparin -warfarin -new - dabigitran exilate, rivaroxiban.... |
DABIGITRAM EXILATE
- direct thrombin (factor IIa) effect RIVAROXIBAN - direct factor Xa inhibitor both are active immediately, require no monitoring, are expensive, have the letter 'X' in them |
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eg of anticoagulants used IN VITRO
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-HEPARIN
-calcium chelators, eg CITRATE and ethylenediamine tetra-acetic acid (EDTA) |
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what is INR?
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international normalised ratio
derived from ratio of patient's clotting time:normal control value |
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platelets are normally activated by what?
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-collagen
-thrombin -adjacent platelets releasing - ---thromboxane A2, ---ADP ---serotonin (5-HT) |
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what normally suppresses platelet aggregation? how?
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PROSTACYCLIN (PGI2)
--stimulates ADENYLATE CYCLASE ----increases cAMP ------inhibits Ca++ mobilisation ------inhibits aggregation NITRIC OXIDE --stimulates GUANYLATE CYCLASE ----increases cGMP ------inhibits Ca++ mobilisation ------inhibits platelet aggregation and adhesion |
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tell me 5 antithrombolytics
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-aspirin
-dipyramidole -epoprostenol -clopidogrel -abciximab |
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tell me about
-aspirin.... -dipyramidole -epoprostenol -clopidogrel -abciximab |
ASPIRIN
-irreversibly inhibits COX enzyme -inhibits platelet synthesis of thromboxane A2 (cannot recover as platelet have no nucleus) also inhibits endothelial production of prostacyclin, but this can be recovered by new COX synthesis |
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tell me about
-aspirin -dipyramidole.... -epoprostenol -clopidogrel -abciximab |
DIPYRAMIDOLE
inhibits cyclic nucleotide phosphodiesterases which digest cAMP and cGMP |
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tell me about
-aspirin -dipyramidole -epoprostenol... -clopidogrel -abciximab |
EPOPROSTENOL
-stabilised prostacyclin -short duration - used for haemodialysis |
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tell me about
-aspirin -dipyramidole -epoprostenol -clopidogrel.... -abciximab |
CLOPIDOGREL
-blocks platelet ADP receptors, preventing GPIIb/IIIa exposure -used in DAPT with aspirin (different mode of action) |
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tell me about
-aspirin -dipyramidole -epoprostenol -clopidogrel -abciximab.... |
ABCIXIMAB
-MAB to GPIIb/IIa -blocks GPIIb/IIa receptors exposed by any pathway antigenic - can only be used once |
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tell me about these wee fibrinolytic fellows
tissue plasminogen activator (t-PA)... streptokinase |
t-PA
- an enzyme produces by vascular endothelium -CLOT SELECTIVE - only activates plasminogen bound to FIBRIN |
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tell me about these wee fibrinolytic fellows
tissue plasminogen activator (t-PA streptokinase.... |
STREPTOKINASE
-not an enzyme, activates plasminogen by bringing about a conformational change -antigenic |
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what would you use a fibrinolytic for
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- venous thrombosis
-MI -thrombotic stroke -PE |
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how would you treat a haemorrhage caused by a fibrinolytic drug?
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TRANEXAIC ACID - an inhibitor of plasminogen activation
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