Warfarin

Question 1

What class of drug is warfain?

Answer 1

Vitamin K antagonist

Question 2

What are the uses of warfarin?

Answer 2

• venous thromboembolism
• PE
• DVT + secondary prevention
• superficial vein thrombosis
• AF when DOAC not suitable
• pre cardio version
• after prosthetic heart valves

Question 3

What is the mechanism of action?

Answer 3

• Inhibition of vitamin K dependent clotting factors
• Inhibits conversion of vitamin K to active reduced form by inhibiting VKOR

Question 4

What are the adverse drug drug reactions of warfarin?

Answer 4

• bleeding
• epistaxis
• spontaneous retroperitoneal bleeding

Question 5

What are important drug drug interaction with warfarin?

Answer 5

• CYP2C9 inhibitor
• other anticoagulants
• phenytoin, barbiturates, rifampicin, St John’s wort: increase [plasma]
• NSAIDs: both bind to albumin