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Warfarin: uses, side effects & brands
Warfarin is a long-established blood thinner needing regular INR monitoring. It belongs to the Blood thinner (anticoagulant) group. These reduce the blood’s tendency to clot, preventing strokes and dangerous clots.
Drug type — dosing is set by your doctor
| Measure | Range |
|---|---|
| Drug class | Blood thinner (anticoagulant) |
| Type | Prescription |
| Dose | Individual — ask your doctor or pharmacist |
What it is used for
- Preventing stroke in atrial fibrillation
- Treating and preventing clots in legs or lungs
- Preventing clots with mechanical heart valves
Common brand names
- India: Warf, Uniwarfin
- Worldwide: Coumadin, Jantoven
Common side effects
- Bruising easily
- Bleeding gums or nosebleeds
- Heavier periods
- Hair thinning (uncommon)
Before taking it — precautions
- Needs regular INR blood tests; keep vitamin K foods (leafy greens) steady, not stopped or started suddenly
- Many medicines, antibiotics, painkillers and herbal products change its effect; tell every doctor and dentist
- Must not be used in pregnancy (harm to the baby); tell your doctor about liver disease or bleeding problems
When to see a doctor urgently
- Black or bloody stools, or vomiting blood (urgent)
- Severe headache, confusion or weakness (possible brain bleed, urgent)
- Bleeding that will not stop or large unexplained bruises
Frequently asked questions
Why do I need INR tests?
Warfarin's effect varies with diet, other medicines and illness. The INR test checks that your blood is thinned enough but not too much.
Can I eat green vegetables?
Yes, but keep the amount fairly steady. Sudden big changes in vitamin K foods change how warfarin works.
Can I take painkillers with warfarin?
Avoid aspirin and NSAIDs like ibuprofen unless your doctor advises; paracetamol is usually preferred, but check first.
Explore more
Sources & further reading
- World Health Organization (WHO)
- MedlinePlus — U.S. National Library of Medicine
- Ministry of Health & Family Welfare, India
- Indian Council of Medical Research (ICMR)
Reviewed by Dr. Sanjay Anbu, MBBS. MedDroid is an AI medical assistant and can make mistakes. It provides general health information, not a diagnosis or medical advice — always consult a qualified clinician. In an emergency, contact your local emergency number immediately.