Health supplements containing omega-3 fatty acids are widely used to treat a variety of health conditions, including heart disease and high cholesterol. Although omega-3 fatty acid supplements, such as fish oil, have shown promising health benefits and are generally safe, they may cause interactions with certain prescription medications, particularly Coumadin. Like any health supplement, ask your doctor before taking omega-3 supplements, especially if you are on Coumadin.
Interaction
Omega-3 fatty acid supplements, such as fish oil, can potentially increase the activity of medications that have an anti-coagulant effect on the blood, warns the University of Maryland Medical Center. Coumadin, which is the brand name of the anti-coagulant medication warfarin, is a widely used anti-coagulant medication that may be affected by omega-3s. Increasing the activity of anti-coagulants can increase the risk of excess bleeding or bruising. You should only take omega-3 supplements at the same time as Coumadin if directed to do so by your doctor or another qualified health care provider.
Case Reports
There are at least two reports of interactions between fish oil supplements and Coumadin. The activity of Coumadin is reported by a measurement known as the international normalized ratio, or INR. Taking fish oil at the same time as Coumadin has been reported to increase INR levels, reports an article published in the medical journal "Annals of Pharmacotherapy." This effect usually disappears after patients stop taking fish oil, strongly suggesting the effect is caused by the fish oil.
Dangers
When the INR is increased, blood takes longer to clot. High INR levels indicate that small cuts or bumps may result in uncontrollable bleeding and severe blood loss. In one case, the increase in INR was so large that the patient was immediately hospitalized to control the risk of severe bleeding, reports an article published in the medical journal "Achives of Medical Research."
Mechanism
The exact reason behind the effect of omega-3 fatty acid supplements on Coumadin is poorly understood. Doctors theorize that omega-3 fatty acids may affect the process of platelet aggregation in which specialized blood cells known as platelets clump together to form a blood clot. Alternatively, omega-3 fatty acids may interact with a parallel chain of biochemical coagulation reactions that require vitamin K, explains the article published in the "Annals of Pharmacotherapy."
References
- "Annals of Pharmacotherapy"; Decreased Warfarin Effect After Initiation of High-Protein, Low-Carbohydrate Diets; S.J. Beatty et al.; April 2005
- "Annals of Pharmacotherapy"; Fish Oil Interaction with Warfarin; M.S. Buckley et al.;; January 2004
- "Archives of Medical Research"; Extremely Prolonged INR Associated with Warfarin in Combination with Both Trazodone and Omega-3 Fatty Acids; M. Jalili and A.R. Dehpour; November 2007
- MedlinePlus: Fish Oil; February 2011
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