Warfarin

Question 1

Drug Class

Answer 1

Vitamin K antagonist

Question 2

Active

Answer 2

Warfarin

Question 3

Indications

Answer 3

Prevention and treatment of DVT

Prevention of thromboembolism in patients with prosthetic heart valves

Prevention of stroke in patients with AF and in patients with previous MI and increased embolic risk

Question 4

Dose Range

Answer 4

Usually start with 5 mg daily for 2 days then adjust according to INR.

Usual maintenance dose, 1–10 mg daily.

Target INR 2-3 except for heart valves which is higher.

Question 5

SE’s

Answer 5

• bleeding
• skin necrosis
• alopecia
• purple discolouration of toes
• allergic reaction
• GI upset (n, v, d)

Question 6

Counselling

Answer 6

Labels: 5, 10a

• Take tablets at about the same time every day; use a calendar or ‘anticoagulant book’ to keep a record of your dose and to mark off the date immediately after taking a dose.
• If you forget to take a dose and it is within 3 hours then you can take it. Otherwise do not take tablets to catch up and skip that dose but take your next dose when it is due and tell your doctor or laboratory. Do not take a double dose.
• Always take the same brand of tablets.
• This medicine is affected by vitamin K which is found in certain foods. Maintain a normal, balanced diet without varying it too much, to keep your intake of vitamin K stable. The foods that are highest in Vitamin K include leafy green vegetables like spinach, cabbage, brussel sprouts, broccoli, parsley etc.
• Avoid drinking large amounts of cranberry juice as this may increase the effects of warfarin.
• Avoid excessive alcohol consumption; 1–2 standard drinks per day is generally safe.
• This medication interacts with many other medications and foods - Tell your doctor and pharmacist that you are taking this medicine before starting or stopping any other medication or taking vitamin supplements, herbal or over-the-counter products.
• Tell your dentist, podiatrist, physiotherapist or chiropractor that you are taking this medication.
• You need regular blood tests with this medication; call for result within 24 hours of the test and before the next dose, in case it needs adjusting. Extra blood tests may be needed while you have any other serious illness.
• Since you have an increased tendency towards bleeding, take extra precautions/avoid activities that may lead to injury. Talk to your doctor.

Extra tips:
• use a non-slip bath mat when bathing
• use a soft bristle toothbrush
• use gloves when gardening and have a clean bandage with you in case you scratch yourself and begin to bleed
• use an electric shaver

• Look out for signs of bleeding and tell your doctor immediately if you have any unexplained bruising, prolonged bleeding, dark red or brown urine, or dark red or black faeces.

Question 7

Monitoring

Answer 7

• INR

- unexplained bruising, prolonged bleeding, dark red or brown urine, or dark red or black faeces