If you are currently being treated with any of the following medications, you should not use omega-3 fatty acid supplements, including eicosapentaenoic acid (EPA), docosahexaenoic acid (DHA), and alpha-linolenic acid (ALA), without first talking to your health care provider.

Blood-thinning medications -- Omega-3 fatty acids may increase the effects of blood thinning medications, including aspirin, warfarin (Coumadin), and clopedigrel (Plavix). While the combination of aspirin and omega-3 fatty acids may actually be helpful under certain circumstances (such as in heart disease), they should only be taken together under the guidance and supervision of a health care provider.

Blood sugar lowering medications -- Taking omega-3 fatty acid supplements may increase fasting blood sugar levels. Use with caution if taking blood sugar lowering medications, such as glipizide (Glucotrol and Glucotrol XL), glyburide (Micronase or Diabeta), glucophage (Metformin), or insulin, as omega-3 fatty acid supplements may increase your need for the medication(s).

Cyclosporine -- Taking omega-3 fatty acids during cyclosporine (Sandimmune) therapy may reduce toxic side effects, such as high blood pressure and kidney damage, associated with this medication in transplant patients.

Etretinate and topical steroids -- The addition of omega-3 fatty acids (specifically EPA) to the drug therapy etretinate (Tegison) and topical corticosteroids may improve symptoms of psoriasis.

Cholesterol-lowering medications -- Following certain nutritional guidelines, including increasing the amount of omega-3 fatty acids in your diet and reducing the omega-6 to omega-3 ratio, may allow a group of cholesterol lowering medications known as "statins", including atorvastatin (Liptor), lovastatin (Mevacor), and simvastatin (Zocor) to work more effectively.

Nonsteroidal anti-inflammatory drugs (NSAIDs) -- In an animal study, treatment with omega-3 fatty acids reduced the risk of ulcers from nonsteroidal anti-inflammatory drugs (NSAIDs), including ibuprofen (Motrin or Advil) and naproxen (Alleve or Naprosyn). More research is needed to evaluate whether omega-3 fatty acids would have the same effects in people.