About warfarin sodium usp
Vitamin K antagonist anticoagulant
Used for
- Prevention and treatment of blood clots
- Prevention of stroke in atrial fibrillation
- Prevention of clots with mechanical heart valves
Usual adult dose
Individualized and adjusted using regular INR blood tests; starting doses vary, often 2–5 mg once daily.
Usual dose in children
Specialist-directed, individualized dosing adjusted with frequent INR tests.
Common side effects
- Bleeding or bruising
- Nausea, vomiting, or diarrhea
- Skin rash
- Rarely, painful skin damage or purple toes
Important warnings
- Can cause serious or fatal bleeding; seek urgent care for heavy bleeding.
- Dose must be guided by INR tests; changes in diet or health can alter it.
- Many medicines, supplements, and alcohol affect warfarin; check before starting or stopping anything.
- Avoid during pregnancy in most cases; mechanical heart valves require specialist assessment.
Pregnancy
Can harm the fetus and cause bleeding. Usually avoided; use requires specialist assessment in exceptional circumstances.
Breastfeeding
Generally compatible with breastfeeding; warfarin passes into milk in very small amounts.
Interactions
- Antibiotics, antifungals, aspirin, and many pain medicines can alter bleeding risk or INR.
- Vitamin K intake changes can affect INR; keep intake consistent.
- Herbal products, including St John’s wort, can affect warfarin.
- Alcohol can alter anticoagulation and increase bleeding risk.
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 It may be incomplete or out of date.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.