Vitamin K reverses warfarin's blood-thinning effect
What's happening
Warfarin works by inhibiting vitamin K-dependent clotting factors. Supplementing vitamin K directly counteracts this mechanism, potentially causing dangerous blood clots. Even dietary vitamin K changes can destabilize INR (International Normalized Ratio).
Recommendation
Do NOT supplement vitamin K while on warfarin without medical supervision. Maintain consistent vitamin K intake from food. Inform your doctor of any diet changes.
Timing
Avoid combination entirely
Sources
— FDA Warfarin Label
— American Heart Association
— PMID: 18179505
Frequently Asked Questions
Can I take vitamin k and warfarin together?
Vitamin K reverses warfarin's blood-thinning effect. Do NOT supplement vitamin K while on warfarin without medical supervision. Maintain consistent vitamin K intake from food. Inform your doctor of any diet changes.
How should I time vitamin k and warfarin?
Avoid combination entirely
Is this interaction dangerous?
This interaction is rated “Danger” by Formulate. Warfarin works by inhibiting vitamin K-dependent clotting factors. Supplementing vitamin K directly counteracts this mechanism, potentially causing dangerous blood clots. Even dietary vitamin K changes can destabilize INR (International Normalized Ratio).
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