Is Vitamin K2 (Menaquinone-7, MK-7) Safe with Warfarin?
Free · No account · based on published sources including NIH ODS, FDA drug labels, and peer-reviewed literature
Advise patients on warfarin to avoid initiating MK-7 supplementation without medical supervision. If MK-7 is clinically indicated (e.g., cardiovascular or bone health), monitor INR very closely and adjust warfarin dose accordingly. Inform prescribers of any MK-7 supplement use.
Why this interaction occurs
MK-7 (menaquinone-7), a form of vitamin K2, directly antagonizes warfarin's mechanism of action through the vitamin K cycle. Changes in MK-7 intake can significantly alter INR stability and anticoagulation control.
Evidence
Evidence level: moderate.
Data source
PubMed - PMID 38172964
Reported safety data
The FDA’s adverse event reporting system (FAERS) has received 134,328 reports mentioning Warfarin. This reflects reported cases involving the medication in general — not confirmed causation, and not specific to the Warfarin + supplement combination on this page.
FAERS reports are voluntary and cannot prove that a drug caused an event. Do not use report counts to assess the safety of this specific drug-supplement pair.
Frequently asked questions
Related interactions
All Vitamin K2 (Menaquinone-7, MK-7) interactions → · All Warfarin interactions →
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Educational only — not medical advice.
Always confirm with your doctor or pharmacist.