PBL 8 - new anticoagulants

Question 1

what are the DOACs?

Answer 1

apixaban, dabigatran, edoxaban, rivaroxaba

Question 2

describe apixaban

Answer 2

• direct inhibitor of FXa
• potent oral reversible direct and selective active site inhibitor of FXa
• inhibits free and clot-bound FXa and prothrombinase activity
• has no direct effect on platelet aggregation — indirectly inhibits aggregation induced by thrombin
• prevents thrombin generation and thrombus development

Question 3

describe dabigatran

Answer 3

• prodrug with no activity
• competitive reversible direct thrombin inhibitor
• following oral administration, dabigatran etexilate is rapidly absorbed and converted to active dabigatran by esterase-catalysed hydrolysis in the liver and the plasma
• thrombin enables conversion of fibrinogen to fibrin during the coagulation cascade
• therefore thrombin inhibition prevents the development of a thrombus
• inhibits free thrombin, fibrin-bound thrombin and thrombin-induced platelet aggregation

Question 4

describe edoxaban

Answer 4

• direct inhibitor of FXa
• inhibits free FXa and prothrombinase activity
• prevents thrombin generation and thrombus development (like with apixaban)

Question 5

describe rivaroxaban

Answer 5

• direct inhibitor of FXa

- prevents thrombus development in the same way as apixaban and edoxaban

Question 6

describe warfarin

Answer 6

inhibits synthesis of vitamin K dependent clotting factors eg. FII, FVII, FIX, FX, protein C and protein S

Question 7

dosing for warfarin?

Answer 7

individualised to maintain target INR for that patient and condition that they’re on it for

Question 8

doac’s vs warfarin

Answer 8