Is Quercetin Safe with Clopidogrel?
Free · No account · based on published sources including NIH ODS, FDA drug labels, and peer-reviewed literature
Avoid this combination. Quercetin may paradoxically both reduce clopidogrel effectiveness and increase overall bleeding risk. Inform your cardiologist or prescriber about all supplement use.
Why this interaction occurs
Clopidogrel requires CYP2C19-mediated bioactivation to its active thiol metabolite. Quercetin inhibits CYP2C19, potentially reducing active metabolite formation and diminishing antiplatelet efficacy — a concern particularly in high cardiovascular risk patients. Simultaneously, quercetin's direct antiplatelet effects may increase bleeding risk, creating an unpredictable net effect on hemostasis.
Evidence
Evidence level: moderate.
Reported safety data
The FDA’s adverse event reporting system (FAERS) has received 108,615 reports mentioning Clopidogrel. This reflects reported cases involving the medication in general — not confirmed causation, and not specific to the Clopidogrel + 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 Clopidogrel interactions →
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Educational only — not medical advice.
Always confirm with your doctor or pharmacist.