Drug interactions
omega-3 fatty acids (fish oil) + warfarin
For healthcare professionals — reference only. This page is a brief summary, not medical advice and not a substitute for official labeling or clinical judgement. Always verify before prescribing or dispensing.
Overview
Additive effects on hemostasis may increase bleeding risk; INR impact is variable/minimal but reported. Risk higher with initiation, dose changes, or high-dose fish oil.
Mechanism of action
Antiplatelet effects of omega-3 fatty acids (↓ platelet aggregation) with anticoagulation by warfarin; possible modest INR increase in some cases.
Clinical management
Do not avoid routinely, but monitor closely. Check INR within 1–2 weeks after starting, stopping, or changing fish oil dose; counsel on bleeding. Avoid or use caution with >3 g/day EPA+DHA. Adjust warfarin dose if INR rises.
Drug reference
References
- Lovaza (omega-3-acid ethyl esters) Prescribing Information — FDA Label
- Omega-3 fatty acids: Drug information — Lexicomp
- Warfarin: Drug information — Lexicomp
Frequently asked questions
Can I take omega-3 fatty acids (fish oil) with warfarin?
The interaction is rated: Moderate. Additive effects on hemostasis may increase bleeding risk; INR impact is variable/minimal but reported. Risk higher with initiation, dose changes, or high-dose fish oil.
How serious is the interaction between omega-3 fatty acids (fish oil) and warfarin?
The interaction is rated: Moderate. Evidence level: Moderate.
How is the interaction between omega-3 fatty acids (fish oil) and warfarin managed?
Do not avoid routinely, but monitor closely. Check INR within 1–2 weeks after starting, stopping, or changing fish oil dose; counsel on bleeding. Avoid or use caution with >3 g/day EPA+DHA. Adjust warfarin dose if INR rises.
Why do omega-3 fatty acids (fish oil) and warfarin interact?
Antiplatelet effects of omega-3 fatty acids (↓ platelet aggregation) with anticoagulation by warfarin; possible modest INR increase in some cases.
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