Drug interactions
Vitamin a + Warfarin
Severity: Minor
Vitamin a and Warfarin: minor interaction.
Last updated
For healthcare professionals — reference only. This page is a brief summary, not medical advice and not a substitute for official labeling or clinical judgement. Always verify before prescribing or dispensing.
Summary
High-dose vitamin A has been reported to increase warfarin effect and bleeding tendency. Evidence is limited and mostly with large doses.
What this interaction means in plain words
Vitamin a and Warfarin have a small, usually unimportant interaction. Most people can take both; the pharmacist may still mention it so that any unexpected effect is recognised.
Vitamin a belongs to Gastrointestinal Tract; Warfarin belongs to Cardiovascular.
Why it happens
Mechanism unclear; possibly interference with vitamin K-dependent coagulation.
What to do
Avoid high-dose vitamin A supplements and check INR if supplementation changes.
What to ask your pharmacist
- Is there anything I should notice while taking both?
- Do I need to tell my doctor at the next visit?
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Other interactions of Warfarin
- Defibrotide + Warfarin Contraindicated
- Ketorolac + Warfarin Contraindicated
- Abciximab + Warfarin Major
- Acetylsalicylic acid + Warfarin Major
- Adagrasib + Warfarin Major
- Amiodarone + Warfarin Major
Other interactions of Vitamin a
- Acitretin + Vitamin a Major
- Etretinate + Vitamin a Major
- Isotretinoin + Vitamin a Major
- Palovarotene + Vitamin a Major
- Bexarotene + Vitamin a Moderate
- Minocycline + Vitamin a Moderate
Frequently asked questions
Can I take Vitamin a with Warfarin?
MediHelp rates the interaction as minor. Vitamin a and Warfarin have a small, usually unimportant interaction. Most people can take both; the pharmacist may still mention it so that any unexpected effect is recognised. High-dose vitamin A has been reported to increase warfarin effect and bleeding tendency. Evidence is limited and mostly with large doses.
How serious is the interaction between Vitamin a and Warfarin?
MediHelp rates it minor, on a four-level scale (minor, moderate, major, contraindicated) based on published labels and references. What to do, in brief: Avoid high-dose vitamin A supplements and check INR if supplementation changes.
What other medicines interact with Warfarin?
MediHelp also lists interactions of Warfarin with, for example, Defibrotide, Ketorolac, Abciximab. The full list is on the Warfarin page.
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