Warfarin

Question 1

warfarin - mechanism of action

Answer 1

• inhibits epoxide reductase preventing the reduction of vitamin K to its active hydroquinone form.
• this is turn acts as a co-factor in the carbohydrate of clotting factor II, VII, IX, and X and protein C.

Question 2

Indications for warfarin

Answer 2

mechanical heart valves
venous thromboembolism
atrial fibrillation

Question 3

what is used to monitor patients on warfarin?

Answer 3

patients are monitored using the INR, the ratio of the prothrombin time for the patient over the normal prothrombin time.

Question 4

factors that may poteniate warfarin?

Answer 4

• liver disease
• p450 enzyme inhibitors
• drugs which displace warfarin from plasma albumin, e.g. NSAID’s

Question 5

side - effects of warfarin?

Answer 5

• haemorrhage
• teratogenic, although can be used in breastfeeding mothers
• skin necrosis
• purple toes