Anticoagulants: warfarin and doac

Question 1

Mode of action of warfarin

Answer 1

Vitamin K antagonist

Vitamin K is essential for production of prothrombin and coagulation factors)

Question 2

How long does warfarin take to have an effect

Answer 2

3 days

Question 3

When is warfarin used

Answer 3

Pts with

• Replaced heart valves
• Atrial fibrillation
• Pulmonary embolism
• DVT

Question 4

How to monitor action of warfarin

Answer 4

INR (prothrombin time increases whilst taking warfarin or due to liver disease)

Question 5

How often to monitor INR

Answer 5

2x per week until you figure out dosage then increase interval gradually

Question 6

How and why can warfarin be reversed

Answer 6

By vitamin K

• If patient is bleeding
• If INR>8-10
• Warfarin overdose

Question 7

How to counsel taking warfarin

Answer 7

Must stick to regimen
Take at 6pm
If miss a dose, then not take 2 doses
-Females should not become pregnant whilst taking warfarin
-avoid excessive consumption of green vegetables and beetroot and liver
-Not have substantial changes to diet

Question 8

If women need anticoagulants, what do you use

Answer 8

LMWHs during pregnancy

Question 9

Mode of action of DOAC dabigatran

Answer 9

Oral thrombin inhibitor

Question 10

Mode of action of DOAC Apixiban and rivaroxaban

Answer 10

Oral inhibitors of activated factor X