Many of us make a clear distinction between the drugs we take and the vitamins or supplements we use. It seems logical enough for our brains, but our bodies don’t recognize categories like that. Anything we ingest may get pressed into service. Conversely, supplements might interact with medications or with each other. One reader asks how to safely take fish oil.
How Can You Safely Take Fish Oil?
Q. In a recent health newsletter, I read that you should avoid fish oil supplements if you take a blood thinner. Is this true? If it is, why hasn’t my cardiologist suggested that I stop taking fish oil?
A. A lot depends upon which anticoagulant you are taking. Years ago there were case reports suggesting that fish oil supplements might “thin” the blood too much if someone were taking warfarin (Coumadin). People who took fish oil in conjunction with warfarin had increased INR values on a blood test that indicates a higher risk for hemorrhage (Buckley et al, Annals of Pharmacotherapy, Jan., 2004; Jalili & Jehpour, Archives of Medical Research, Nov. 2007).
The Value of Fish Oil Supplements:
Many people take fish oil to reduce inflammation linked to conditions such as arthritis, asthma and coronary heart disease (Fetterman & Zdanowicz, American Journal of Health-System Pharmacy, July 1, 2009). Fish oil may have mild anti-clotting activity of its own, although it might not be dangerous (Wang et al, Medicines, Sep. 2015). According to a review in Australian Family Physician, you can safely take fish oil at doses under 3000 mg/day even if you also take aspirin, clopidogrel (Plavix) or even warfarin (Kreijkamp-Kaspers et al, Australian Family Physician, July 2015).
The same review notes that there are no studies of fish oil in combination with newer anticoagulant drugs such as apixaban (Eliquis), dabigatran (Pradaxa), prasugrel (Effient), rivaroxaban (Xarelto) or ticagrelor (Brilinta). As a result, it probably would be prudent not to take fish oil if you are taking any such anticoagulant medications.
Your cardiologist may not be aware you are taking fish oil. Or possibly she or he has not seen any studies showing that there is an interaction with your blood-thinning medication. That might explain why you’ve not been given a clear recommendation. Eating fish should not pose a problem. This dietary approach could be a good way to get valuable omega-3 fatty acids, though not at the high doses supplements can provide.