Bleeding Risk with Fish Oil and SSRIs
Fish oil supplementation does not increase bleeding risk when combined with SSRIs, and can be safely continued in patients taking these medications together. 1, 2
Evidence for Fish Oil Safety
The highest quality evidence demonstrates that fish oil does not cause clinically significant bleeding, even in high-risk scenarios:
The Society for Perioperative Assessment and Quality Improvement (SPAQI) 2021 consensus explicitly states that fish oil/omega-3 fatty acid preparations should be continued perioperatively, as prior concerns about bleeding risk have not been borne out in prospective studies 1
The European Food Safety Authority confirms that long-term supplemental intakes of EPA and DHA combined up to 5g daily do not increase the risk of spontaneous bleeding or bleeding complications 2
A large multinational randomized controlled trial (n=1516) in cardiac surgery patients receiving high-dose fish oil (8-10g preoperatively, then 2g/d postoperatively) found no increased bleeding risk compared to placebo (OR 0.81,95% CI 0.53-1.24), and actually resulted in fewer blood transfusions 3
Another study of 182 patients taking high-dose fish oil (mean 3g) combined with aspirin AND clopidogrel showed no increase in major or minor bleeding compared to aspirin and clopidogrel alone over 33 months of follow-up 4
SSRI Bleeding Risk Context
SSRIs carry an inherent bleeding risk that is substantially amplified by anticoagulants and NSAIDs, but fish oil does not fall into this high-risk category:
SSRIs increase gastrointestinal bleeding risk (OR 1.2-1.5) at any time during treatment 5
The bleeding risk with SSRIs is substantially higher when combined with antiplatelet agents, NSAIDs, aspirin, or anticoagulants like warfarin 5, 6
Warfarin plus SSRI more than doubles bleeding risk compared to warfarin alone 5
NSAIDs (ibuprofen, naproxen) plus SSRI significantly increase gastrointestinal bleeding risk 5
Clinical Recommendation
For patients taking both fish oil and SSRIs:
Continue fish oil supplementation without dose adjustment or discontinuation 1, 2
Standard doses (1-4g daily) are safe, and even doses up to 5g daily do not increase bleeding risk 2
Focus bleeding risk assessment on concomitant use of NSAIDs, aspirin, antiplatelet agents, or anticoagulants rather than fish oil 5, 6
Screen for over-the-counter NSAID use, which is the most commonly overlooked bleeding risk factor in SSRI-treated patients 5
Consider gastroprotective agents (PPIs) if the patient is taking NSAIDs or has GI risk factors, not because of fish oil 5
Special Monitoring Considerations
For patients on warfarin plus SSRI who are also taking fish oil:
Monitor INR closely when initiating or changing fish oil doses, as fish oil (1-2g daily) can increase INR through antiplatelet effects 2
The bleeding risk elevation comes from the warfarin-SSRI combination (which more than doubles risk), not from adding fish oil 5
One notable exception exists:
- Patients receiving ibrutinib (for chronic lymphocytic leukemia) should avoid fish oil supplements due to reported epistaxis when combined 2
Common Pitfalls to Avoid
Do not discontinue fish oil before surgery based on bleeding concerns—this outdated recommendation is not supported by current evidence 1, 3
Do not attribute SSRI-related bleeding risk to fish oil—the mechanistic concern about fish oil's antiplatelet effects has not translated to clinical bleeding in prospective trials 7, 4, 3
Do not overlook NSAIDs as the primary modifiable bleeding risk factor in SSRI-treated patients 5
Fish oil can reduce platelet aggregation in vitro, but this effect does not increase bleeding risk during or after surgery in randomized controlled trials 1