Essay: Discuss anticoagulants, MOA, evidence, compare new ones to warfarin Flashcards Preview

Module 3 > Essay: Discuss anticoagulants, MOA, evidence, compare new ones to warfarin > Flashcards

Flashcards in Essay: Discuss anticoagulants, MOA, evidence, compare new ones to warfarin Deck (15):
1

Warfarin
- Uses and usage

- Most commonly used anticoagulant

- DVT, PE, AF
- Other thrombotic events

2

Warfarin MOA

- CYP2C9 converts warfarin to s-warfarin

- Prevents Vitamin K-dependent synthesis of Ca-dependent clotting factors

- FII, FVII, FIX and FX

also
- Protein C
- Protein S
- Protein Z

3

Warfarin risk, monitoring (and trouble)

Haemorrhage
- Narrow therapeutic window

Problem with plasma warfarin
- Effect is varied in individuals downstream of plasma concentration so it's useless for monitoring

Monitoring
- INR

4

UF Heparin MOA

- Binds to antithrombin III (AT)

- Conformational change activates AT

- AT inactivates FXa and FIIa (thrombin)*

*Thrombin must also bind the heparin polymer for its inhibition (size dependent)

5

UF Heparin reversal

- Complete reversal with protamine

- Irreversibly binds to heparin and inactivates it

6

NOACs

Non-vitamin K antagonist oral anticoagulants

- Direct inhibitors
- Selective for FIIa (thrombin) or Xa

7

Advantages of NOACs over VKAs

- safety (lower major bleeding incidence)

- wider therapeutic window

- convenience of use

- minor drug/food interactions

- no need for lab monitoring

8

Disadvantages of NOACs vs VKAs

- Contraindications: pregnancy, childhood

- not yet approved for use in some thrombophillic states

- malignancy, mech MV, antiphospholipid syndrome

9

Dabigatran (RE-LY)

- Dabigatran vs warfarin

- similar risk of stroke/ systemic embolism

- lower risk of major haemorrhage

10

Daigatran MOA

- Direct selective FIIa inhibitor

- prevents fibrinogen conversion to fibrin

11

Rivaroxiban (ROCKET-AF)

- as effective at preventing stroke/embolism

- lower risk of intracranial haemorrhage

- lower risk of fatal bleeding

12

Rivaroxiban MOA

- Direct selective inhibitor of FXa

13

Apixaban (ARISTOTLE)

- superior prevention of stroke, systemic embolism

- lower haemorrhage (lower mortality)

14

Thrombin pathway

- FXa converts prothrombin (FII) -> thrombin (FIIa)

- FIIa converts fibrinogen to fibrin

15

Problems with warfarin

- Slow onset of action

- Narrow therapeutic window

- Need for laboratory monitoring

- Drug/food interactions

- High risk of severe bleeding