anticoagulants (warfarin)

Question 1

Indications of warfarin?

Answer 1

transient cerebral ischaemic attacks and prophylaxis of: systemic embolization in patients with rheumatic heart disease and atrial fibrillation, insertion of prosthetic heart valves, venous thrombosis, pulmonary embolism

Question 2

Contraindications of warfarin?

Answer 2

48 hours postpartum, significant bleeding, haemorrhagic stroke

Question 3

Mechanism of action of warfarin

Answer 3

inhibits the synthesis of vitamin K dependent clotting factors (2, 4 and 5) by blocking an enzyme (vitamin K epoxidase reductase) that creates vitamin K1, this reduces the coagulant activity of the blood

Question 4

Side effects of warfarin

Answer 4

alopecia, rash, excessive bleeding

Question 5

Monitoring requirements of warfarin

Answer 5

baseline prothrombin time should be monitored, INR (international normalised ratio - how long it takes blood to form a clot) should be determined daily or on alternate days at the beginning of treatment then up to every 12 weeks

Question 6

Treatment cessation of warfarin

Answer 6

increased level of clots

Question 7

Patient and carer advice for warfarin

Answer 7

anticoagulant treatment booklets should be given to all patients and their carers, these include advice, an alert card to be carried by the patient always and a section for recording INR results and dosage. anything that affects vitamin K absorption can increase the effect of warfarin, particularly some antibiotics