Fish Oil and Warfarin: what the published research says
PubMed indexes 8 records that name Fish Oil and Warfarin together, either in the title or in an interaction, co-administration, or pharmacokinetic context. Each one is listed below with its study design and, where the abstract states one, the authors’ own conclusion, quoted and linked. This page reports that literature. It does not tell you whether to combine them.
Every statement below is attributed to a named, dated, linked source.
This page lists published research relevant to Fish Oil and Warfarin. It deliberately does not state whether the combination is safe, whether it interacts, in which direction, at what dose, or how far apart to take them.
A study appearing here is not proof that an interaction exists. Two substances can be named together in a paper that never tested them in combination, and a source listed as background may cover only one of them.
Findings are quoted from each abstract as the authors wrote them. NutriStack has not re-analysed, pooled, or reconciled them, and they may disagree with each other.
NutriStack’s own interaction assessment for this pair is not published here. It has not completed qualified-human clinical review, so it is withheld from search. See the publication gate.
Nothing here is medical advice. Decisions about prescription medication and supplements belong with your prescriber or pharmacist, who can see your full regimen.
The research
8 studies naming Fish Oil and Warfarin.
Strongest relevance first: papers naming both substances in the title, then human trials and systematic reviews.
Journal of trauma nursing : the official journal of the Society of Trauma Nurses · 2017 · PMID 28033135
Case ReportsHuman subjects
“Masked by its many benefits, the risks of omega-3 fatty acid supplementation are often underappreciated, particularly its ability to inhibit platelet aggregation and promote bleeding in patients taking anticoagulant medications. The following details the clinical case of an elderly patient taking warfarin and fish oil supplementation whose warfarin-induced coagulopathy could not be reversed after suffering blunt head trauma.”
American journal of cardiovascular drugs : drugs, devices, and other interventions · 2017 · PMID 28197979
Clinical Trial, Phase I
“OM3-CA did not affect the pharmacokinetics or pharmacodynamics of warfarin or the pharmacodynamic effects of ASA. OM3-CA did not affect platelet function when co-administered with ASA.”
Archives of medical research · 2007 · PMID 17923275
Case ReportsHuman subjects
“Although drug interaction reference texts classify warfarin-trazodone interaction as late-onset and clinically insignificant, this has been questioned in other studies. This particular case illustrates a possible interaction between warfarin and these two medications.”
“These findings are important because of the wide availability of omega-3 fatty acids and the propensity for use of complementary and alternative medicine in patients with cardiovascular disease who are already taking antiplatelet and/or anticoagulant agents. Judicious use of these combinations is advised, and pharmacists can play an important role in educating patients and other health care providers about the bleeding risks associated with combination therapy.”
The Annals of pharmacotherapy · 2004 · PMID 14742793
Case ReportsHuman subjects
“This case reveals a significant rise in INR after the dose of concomitant fish oil was doubled. Patients undergoing anticoagulation therapy with warfarin should be educated about and monitored for possible drug-herb interactions. Pharmacists can play a crucial role in identifying possible drug interactions by asking patients taking warfarin about herbal and other alternative medicine product use.”
“Omega-3 supplementation with fish and krill oil does not significantly affect long-term warfarin control and bleeding and thromboembolic events when consumed concurrently in patients managed at an anticoagulation clinic.”
Journal of thrombosis and thrombolysis · 1998 · PMID 10767122
“One bruising episode was reported, yet no major bleeding episodes were observed during the study. Fish oil supplementation in doses of 3-6 grams per day does not seem to create a statistically significant effect on the anticoagulation status of patients receiving chronic warfarin therapy.”
“Evidence of low-strength indicates benefits of omega-3 fatty acids (plus statin, or calcium channel blockers and antiplatelets) and garlic (plus nitrates or warfarin) on triglycerides and HDL-C, respectively. Safety concerns, however, persist.”
Names Fish Oil and Warfarin together in an interaction, co-administration, or pharmacokinetic context.
Limitations
What this evidence cannot tell you.
Search-based evidence indexes have real limits, and it is worth being explicit about them:
Selection. These records were found by searching PubMed titles and abstracts for both substance names alongside interaction and pharmacokinetic terms. Relevant work that phrases things differently, or is not indexed in PubMed, will be missing.
No effect size. The quoted conclusions are the authors’ words about their own study. We have not extracted effect direction or magnitude, and a single study’s conclusion is not a consensus.
Population mismatch. Findings in healthy volunteers, animals, or a specific patient group may not transfer to you, your dose, or your formulation.
Absence is not safety. Few published studies means the combination is under-studied, which is not the same as established as safe.
Nearby evidence
Other pairs with published research.
Pages covering Fish Oil or Warfarin alongside a different substance.
NutriStack is a free iPhone app for organising a supplement routine: what you take, when, and what the published record says about it. Its exploratory interaction checker covers Fish Oil, Warfarin, and several hundred other substances.
The checker is a research and organisation tool, not a clinical decision aid, and its per-pair assessments are excluded from search until they pass claim-level review.
NutriStack is an informational and organizational tool, not a medical service, and not a substitute for professional advice. Always consult a qualified healthcare professional before starting, stopping, or changing any supplement or medication.
