L28 - Anticoagulant therapy Flashcards
Name the three classes of antiplatelet drugs
Cyclooxygenase inhibitor
ADH receptor antagonist
Glycoprotein IIb, IIIa receptor inhibitors
What is the mode of action of aspirin
Inhibits cyclooxygenase
Decrease TXA2
Decresae platelet aggregation
What is the clinical usage of aspirin
Myocardial infaction and stroke
Use in combination with ADH receptor anatgonist in stenting and coronary angioplasty
What are the side effects of aspirin
Risk of prolonged bleeding and increase incidence of gastric irritation and bleeding
What are the two examples of ADH receptor antagonist
Clopiogrel
Prasugrel
What is the mode of action of ADH receptor anatogonist
Inhibit ADH pathway
Decrease platelet aggregation
What is the clinical usage of ADH receptor anatgonist
Use in patient who can’t tolerant aspirin
Use in combination with aspirin for stenting and coronary angioplasty
What are the examples of glycoprotein IIb, IIIa receptor inhibitors
Abciximab
Eptifitabine, tirofiban
What is abciximab?
It is a monoclonal antibodies binding IIb/ IIIa receptor
What are eptifibatine and tirobatine
reversible inhibitors for IIb and IIIa receptor
What are the mode of action of IIb/ IIIa receptor antagonist
IIb/ IIIa are finial commmon pathway for activation of platelets (binding to fibrinogen)
IIb/ IIIa inhibit that
What is the clinical usage of glycoprotein IIb/ IIIa receptor antagonist
Stenting and coronary angioplasty
What are APTT and PT used for in monitoring drug usuage
APTT: heparin
PT: warfin
What are the pharmacological properties of heparin (short term? long term? cross placenta?)
Intermediate - short term use
Doesn’t cross placenta
What are the usuage of heparin?
Stenting and coronary angioplasty
Myocardial infarction
What are the side effects and contraindication of heparin
Bleeding
Haemophilia
Hypersensitivity reaction
What is the pathogenesis of HIT
Antibody development
Target against heparin
Decrease in paltelet, thrombosis
What is the treatment for HIT
Removal of heparin treatment
Protamine sulphate -> combined with heparin as a stable complex
Direct thrombin inhibitor
What is the mode of action of heparin
It allow stronger binding of antithrombin to factor X and thrombin
Inhibit the coagulation pathway
Give two other relatives of heparin
Exonaparin
Fondaparinux
Give three examples of direct thrombin inhibitor
Oral - dabigatron
Parenteral - hirudin, lepirudin, argatroban
What is the mode of action of thrombin inhibitor
Inhibition of thrombin -> decrease fibrin production and platelet activation -> no clot is produced
Give an example of direct factor Xa inhibitor
Rivaroxaban, apixaban
What is the mode of action of warfin
It is structually similar to vitamin K, acting as an antagonist
How is warfin metabolised
Heavily protein bound an by liver cytochrome P450 enzmye
What are the clinical uses of Warfin
Short term: prevent venous thrombosis and pulmonary embolism
Long term: atrial fibrillation –> reduction of thrombosis
prosthetic heart valve –> clot formation
What are the adverse effects of warfin
Bleeding
Cross placenta
Interaction with significant number of drugs
How to reverse warfin toxicity
Dtop using the drugs
Prescribe vitamin K1
Name the four types of thrombolytic drugs and their pharmacological properties/ mode of action
Streptokinase - form comple with proactivator complex => conversion of plasminogen to plasmin => plasmin break down fibrin
Anitreplase - streptokinase plasminogen complex
Urokinase -enzymatic activity -> convert plasminogen to plasmin
tPa -> direct activation of plasminogen -> plasminogen to plasmin -> plasmin breaks down fibrin
What are the therapeutic use of thrombolytic drugs
Multiple pulmoanry emboli, central deep venous thrombosis, acute myocardial infarction
What is the adverse effect of thrombolytic drugs
What can the side effect be treated with
Bleeding
Tranexamic acid or fresh plasma or coagulation factor
What are the source of vitamin K
K1 - green vegetables
K2 - bacteria in the human gut
Give two examples of fibrinolytic inhibitors
Aminocaproic acid
Tranexamic acid
What is the mode of action of fibrinolytic inhibitors
competitor inhibitor of plasminogen activation
