How does warfarin work?
Warfarin blocks vitamin K, which is essential for blood clotting. This slows down the clotting process and reduces the risk of harmful clots forming.
What is warfarin used to treat?
Warfarin is commonly prescribed for:
- Preventing strokes and blood clots in people with atrial fibrillation (AF)
- Treating and preventing deep vein thrombosis (DVT) and pulmonary embolism (PE)
- Preventing blood clots in people with mechanical heart valves
- Certain clotting disorders (such as antiphospholipid syndrome)
Who can take warfarin?
Warfarin is suitable for most adults at risk of blood clots, as prescribed by a doctor.
Who might not be able to take warfarin?
Warfarin may not be suitable if you:
- Have active bleeding or a bleeding disorder
- Have severe liver or kidney disease
- Have uncontrolled high blood pressure
- Are pregnant (warfarin is not usually recommended during pregnancy)
Can I take warfarin if I’m pregnant or breastfeeding?
Warfarin isn’t usually recommended during pregnancy, as it may harm the baby. However, it may be used in some cases under medical supervision. If you are breastfeeding, warfarin is generally considered safe, but speak to your doctor first.
What if I miss a dose?
If you forget a dose, take it as soon as you remember on the same day. If you only remember the next day, skip the missed dose—do not take two doses at once.
How effective is warfarin?
Warfarin is highly effective at preventing blood clots when taken as prescribed and monitored regularly.
What should I do if I take too much?
Taking too much warfarin can cause serious bleeding. If you experience unusual bruising, blood in your urine or stool, or unexplained bleeding, seek urgent medical attention.
What dose of warfarin is usually taken?
- Typical dose: Varies for each person and is adjusted based on INR (International Normalised Ratio) blood tests
- Monitoring: Regular blood tests are needed to ensure the correct dose
Your doctor will determine the correct dose based on your blood clotting levels.
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What are the side effects of warfarin?
Common side effects include:
- Increased bruising
- Bleeding gums or nosebleeds
- Nausea or stomach discomfort
Serious side effects, such as severe bleeding, black stools, or coughing up blood, require urgent medical attention.
How should I take warfarin?
Warfarin is taken as tablets, usually once daily, with or without food. Always follow your doctor’s instructions.
When should warfarin be taken?
Warfarin is usually taken at the same time each day, often in the evening to allow for INR test adjustments.
What are the brand names for warfarin?
Warfarin is available as a generic medicine, but some branded versions include:
- Marevan
- Coumadin (outside the UK)
Final thoughts
Warfarin is an effective anticoagulant, but it requires regular monitoring and careful use to avoid bleeding risks. If you experience any unusual symptoms, speak to your doctor or pharmacist immediately.
