Fish Oil Interactions

Fish oil may increase bleeding risk when combined with warfarin

Apixaban is a direct factor Xa inhibitor that increases bleeding risk on its own. Omega-3 fatty acids in fish oil reduce platelet aggregation in a dose-dependent way; a 2024 JAHA systematic review of 120,643 patients found omega-3 doses of approximately 3 g/day or less of EPA+DHA did not significantly raise bleeding risk, while higher doses (notably high-purity EPA in cardiovascular trials) showed a small absolute increase in bleeding events.

Omega-3 fatty acids in fish oil have mild antiplatelet and anticoagulant effects, reducing thromboxane A2 and prolonging bleeding time. Combined with rivaroxaban's Factor Xa inhibition, this can additively increase bleeding risk, particularly at fish oil doses above 3 g per day.

Naproxen impairs platelet aggregation through COX-1 inhibition, and fish oil EPA and DHA have mild antiplatelet and antithrombotic effects. Combining them can modestly increase bleeding risk, especially at high doses or alongside other blood thinners.

Omega-3 fatty acids in fish oil reduce platelet aggregation and prolong bleeding time slightly, theoretically adding to aspirin's antiplatelet effect. Clinical trials, however, consistently show no clinically significant increase in major bleeding even with high-dose fish oil added to aspirin.