Is Warfarin Safe with Quercetin?
Free · No account · based on published sources including NIH ODS, FDA drug labels, and peer-reviewed literature
Do not combine quercetin with warfarin without close medical supervision. Monitor INR frequently and report any unusual bruising or bleeding immediately.
Why this interaction occurs
Quercetin inhibits CYP2C9, the primary enzyme responsible for warfarin metabolism. This inhibition can significantly raise warfarin plasma levels, increasing anticoagulant effect and risk of serious bleeding events.
Evidence
Evidence level: moderate.
Reported safety data
The FDA’s adverse event reporting system (FAERS) has received 1,497 reports mentioning Quercetin. This reflects reported cases involving the medication in general — not confirmed causation, and not specific to the Quercetin + 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 Warfarin interactions → · All Quercetin interactions →
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Educational only — not medical advice.
Always confirm with your doctor or pharmacist.