Fish Oil With Blood Thinners Like Warfarin
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Can you take fish oil with blood thinners?

From FDA labels, public health agencies and published studies · Reviewed

Short answer: Often, but it is worth telling your prescriber. The NIH Office of Dietary Supplements says fish oil can have antiplatelet effects at high doses and might raise INR with warfarin, but most research found 3 to 6 g a day did not significantly change anticoagulation. A 2014 review found no rise in clinically significant bleeding. Prescription omega-3 labels still say people on blood thinners should have INR checked periodically.

What the NIH fact sheet says

The NIH Office of Dietary Supplements (ODS) omega-3 fact sheet names warfarin (Coumadin) and similar anticoagulants as its example of a medicine interaction. Its points, in order:

  • Fish oil can have antiplatelet effects at high doses, though it appears to be less potent than aspirin.
  • Fish oil might prolong clotting times, shown by a higher INR, when taken with warfarin.
  • Most research indicates that 3 to 6 g a day of fish oil does not significantly affect the anticoagulant status of people taking warfarin.
  • A 2014 review concluded that omega-3s do not affect the risk of clinically significant bleeding.
  • FDA-approved package inserts for prescription omega-3s say studies did not produce clinically significant bleeding episodes, but also say people taking them with anticoagulants should be monitored periodically for changes in INR.

Why warfarin users are asked to report supplements

Warfarin has a narrow window between too little effect and bleeding, and its dose is set from INR results. The MedlinePlus warfarin page tells patients to let their doctor and pharmacist know about all vitamins, nutritional supplements and herbal products, because some may increase bleeding risk. It lists several, including coenzyme Q10, garlic, ginkgo and ginseng, along with aspirin and NSAID pain relievers.

Fish oil is not on that MedlinePlus list, but the prescription omega-3 labels' INR monitoring line, as summarized by ODS, is why a prescriber may want to know about it. See vitamin K and warfarin for the dietary side.

Newer blood thinners and antiplatelet drugs

The ODS fact sheet discusses warfarin and similar anticoagulants. It does not give data for newer anticoagulants such as apixaban or rivaroxaban, or for antiplatelet drugs such as clopidogrel, so this page cannot say how fish oil combines with them. Their labels and your prescriber or pharmacist are the place to check.

ODS lists commonly reported side effects of omega-3 supplements as usually mild: unpleasant taste, bad breath, heartburn, nausea, stomach discomfort, diarrhea, headache and smelly sweat. It also notes that two large trials found 4 g a day of omega-3s for several years slightly raised the risk of atrial fibrillation (an irregular heart rhythm) in people with or at high risk of heart disease.

What to note

The ODS findings are about grams of omega-3 fish oil, and capsule strengths vary. Useful notes for an anticoagulation visit: the product, how many capsules a day, the EPA and DHA content from the label, the date you started, and any unusual bruising or bleeding. Dose Track logs supplements with their amount alongside your INR results and warfarin doses.

Read more on Dose Track: Omega-3 fish oil guide · Krill oil · Cholesterol · Blood clots on TRT

General education drawn from labels, public health agencies and published studies, not personal medical advice. Your prescriber, pharmacist and the label that came with your medicine are the final word. Questions for other users? Ask in the Dose Track community.
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Frequently asked questions

Does fish oil thin your blood?+
ODS says fish oil can have antiplatelet effects at high doses, though it appears less potent than aspirin, and a 2014 review found no rise in clinically significant bleeding.
Can I take fish oil with warfarin?+
ODS says fish oil might raise INR with warfarin, but most research found 3 to 6 g a day did not significantly change anticoagulation. Tell your prescriber so INR can be watched.
How much fish oil is safe with blood thinners?+
ODS reports that most research found 3 to 6 g a day did not significantly affect warfarin. It does not set a safe limit; your prescriber can advise.
Does fish oil interact with apixaban or Eliquis?+
The ODS fact sheet discusses warfarin and similar anticoagulants and does not give data for newer blood thinners. Check with your prescriber or pharmacist.

Sources

  1. NIH Office of Dietary Supplements: Omega-3 fatty acids, fact sheet for health professionals
  2. MedlinePlus: Warfarin (drug information)

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