Is Quercetin Safe with Warfarin?
Free · No account · based on published sources including NIH ODS, FDA drug labels, and peer-reviewed literature
Avoid this combination without direct physician supervision. If used together, increase INR monitoring frequency to weekly. Discontinue quercetin at least 2 weeks before any surgical procedure.
Why this interaction occurs
Quercetin is a potent inhibitor of CYP2C9 and CYP3A4 enzymes, both involved in warfarin metabolism. Studies show quercetin can significantly increase warfarin AUC and half-life. Quercetin also inhibits platelet aggregation via thromboxane pathway suppression, creating a dual mechanism for bleeding risk elevation.
Evidence
Evidence level: moderate.
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 Quercetin interactions → · All Warfarin interactions →
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Educational only — not medical advice.
Always confirm with your doctor or pharmacist.