Is Evening Primrose Oil Safe with Warfarin?
Free · No account · based on published sources including NIH ODS, FDA drug labels, and peer-reviewed literature
Avoid combining Evening Primrose Oil with Warfarin. If already taking both, inform your prescriber immediately and monitor INR levels closely. Do not stop either without medical guidance.
Why this interaction occurs
Evening Primrose Oil contains gamma-linolenic acid (GLA) which inhibits platelet aggregation and thromboxane synthesis. Combined with Warfarin's anticoagulant mechanism, this significantly increases bleeding risk and may unpredictably elevate INR values.
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 Evening Primrose Oil interactions → · All Warfarin interactions →
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Educational only — not medical advice.
Always confirm with your doctor or pharmacist.