Anticoagulant drugs

Question 1

Virchow’s triad

Answer 1

Hypercoagulability, endothelial injury and blood stasis

Question 2

Process of haemostasis

Answer 2

Formation of platelet plug (adhesion, aggregation, activation)
Propagation of clotting (pathways activated, clotting cascade, recruiting platelets)
Termination of clotting (limiting clot formation and stopping the cascade)
Fibrinolysis (activating plasmin and lysis of fibrin)

Question 3

Antiplatelet examples

Answer 3

• Aspirin
• Clopidogrel
• Dipyridamole
• Arterial

Question 4

Anticoagulants

Answer 4

• Warfarin
• Heparins
• Apixaban
• Rivaroxaban
• Dabigatran
• Arterial and venous
• DOAC - direct oral anticoagulant drug- replacing warfarin

Question 5

Thrombolytics

Answer 5

TPA

Arterial and venous

Question 6

Anticoagulants

Answer 6

• Treatment of thromboembolism: arterial (warfarin and DOACs) and venous: heparins, DOACs and warfarins
• Prevention of thromboembolism: prevention of stroke with AF (warfarin and DOACs), mechanical heart valves (warfarin), VTE prophylaxis, high risk thrombophilias

Question 7

What is the CHADVASc score

Answer 7

Measures stroke risk in patients with AF
0 = no anticoagulation needed
1 = probably needed
>1 = definitely immediately needed

Question 8

HASBLED score

Answer 8

Bleeding risk for patients on anti-coagulation

Question 9

WELLs score

Answer 9

Assesses the risk of a patient getting a DVT or PE

Question 10

DOAC examples

Answer 10

Apixaban, rivaroxiban and dabigatran

Question 11

How do DOACs work?

Answer 11

• Rivaroxiban and apixiban bind to 10a inhibit activation of thrombin from prothrombin
• Dabigatran binds directly to prothrombin to stop coagulation cascade

Question 12

Side effects of dabigatran

Answer 12

Dyspepsia and GI

Question 13

DOAC reversal

Answer 13

Idarucizumab for dabigatran

Question 14

Heparins

Answer 14

Binds to antithrombin to increase thrombin inhibition

Question 15

Side effects of heparins

Answer 15

bleeding, thrombocytopenia, hypokalaemia, osteoporosis, renal failure = accumulation

Question 16

Fondaparinux

Answer 16

Similar MOA to heparin, used for acute coronary syndrome

Question 17

Warfarin MOA

Answer 17

Inhibits vit K so no serine protease made

Question 18

Which sites depend on reduced vit K?

Answer 18

2,7,9,10

Question 19

Enzyme interactions and warfarin

Answer 19

• Enzyme inducers increase warfarin metabolism and therefore reduce INR
• Enzyme inhibitors increase INR and risk of bleeding

Question 20

When would rivaroxiban be favoured as an anticoagulant?

Answer 20

No bleeding history and easy dosing regime (if pt forgetful)

Question 21

STEMI

Answer 21

Occlusion of coronary arteries caused by atheroma -> ischaemia -> angina
S1Q3T3 sign