Fish Oil and Warfarin
Supplement–drug interaction evidence from the TruthStack database.
| Severity | HIGH |
|---|---|
| Evidence Tier | Moderate |
| Interaction Type | BLEEDING RISK |
| Mechanism | PHARMACODYNAMIC |
| Last Reviewed | 2026-02-24 |
Summary
Omega-3 fatty acids have antiplatelet properties and may potentiate warfarin anticoagulant effects through reduced thromboxane A2 synthesis. FAERS: 2,371 adverse event reports. Meta-analyses show modest INR increases with high-dose omega-3 (>3g/day). Monitor INR when initiating or changing omega-3 dose.
Higher-Concern Contexts
This interaction may be of particular concern in the following contexts:
- anticoagulant use
CYP Enzyme Profiles
Published CYP enzyme data for compounds in this interaction:
Warfarin: CYP1A2 substrate (weak), CYP2C9 substrate (strong), CYP3A4 substrate (moderate)
Shared Pharmacodynamic Endpoints
Both compounds influence the same physiological endpoints in the same direction:
| Endpoint | Direction | Fish Oil | Warfarin |
|---|---|---|---|
| COAGULATION | DECREASE | WEAK | STRONG |
Cumulative effect on shared endpoints may exceed individual compound profiles. This is relevant to discussion with a prescribing clinician.
API Reference
Open, unauthenticated. Returns JSON. Developer documentation
Sources
Primary: 18775582