About warfarin sodium
Vitamin K antagonist anticoagulant
Used for
- Prevents and treats blood clots, including deep vein thrombosis and pulmonary embolism.
- Prevents stroke and blood clots in atrial fibrillation or with mechanical heart valves.
Usual adult dose
Individualized by blood-test results (INR); often starts at 2–5 mg once daily, then adjusted.
Usual dose in children
Individualized by age, weight, condition, and INR; specialist-supervised dosing is required.
Common side effects
- Bleeding, including bruising or nosebleeds
- Nausea, vomiting, or diarrhea
- Hair loss
- Rarely, painful skin damage or tissue death
Important warnings
- Can cause serious or fatal bleeding; seek urgent care for severe bleeding or head injury.
- Dose needs regular INR blood tests; changes in diet, illness, or medicines can alter results.
- Maintain consistent intake of vitamin K-rich foods; do not start or stop medicines without review.
- Avoid during pregnancy in most cases; mechanical heart valves require specialist assessment.
Pregnancy
Can cause fetal harm, including birth defects and bleeding. Generally avoided during pregnancy except selected specialist-managed cases.
Breastfeeding
Generally considered compatible with breastfeeding; warfarin does not meaningfully enter breast milk.
Interactions
- Many medicines affect warfarin, including antibiotics, antifungals, aspirin, and anti-inflammatory pain relievers.
- Vitamin K supplements and some herbal products can change its effect.
- Alcohol and changes in vitamin K-rich food intake may alter INR.
AI-generated from general medical knowledge, not from this product's official leaflet. It may be incomplete or out of date. Not medical advice — ask a pharmacist or doctor before making any decision.