Warfarin
Brand: Jantoven (Coumadin, discontinued)
Boxed warning · ISMP high-alert drug
Major or fatal bleeding; regular INR monitoring is required.
- Caution
- Skin necrosis and purple-toe syndrome; contraindicated in pregnancy and active bleeding.
- Pregnancy
- Avoid in pregnancy: crosses the placenta and causes birth defects and fetal bleeding (contraindicated except with mechanical heart valves in some cases).
Common side effects
- Bleeding or bruising
- Nosebleeds
- Bleeding gums
- Blood in urine or stool
Key interactions
- Many drugs raise bleeding risk
- Keep vitamin K foods steady (leafy greens)
- Avoid alcohol excess
- NSAIDs and aspirin raise bleeding risk
Counseling points
- Get regular INR blood tests
- Keep leafy-green intake consistent
- Report unusual bleeding or dark stools
- Use a soft toothbrush and care with sharp objects
- Tell all providers you take a blood thinner
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