Omega-3 acid ethyl esters are prescription drugs that contain eicosapentaenoic acid-ethyl ester and docosahexaenoic acid-ethyl ester that are used in combination with changes in diet to lower triglyceride levels in adults with severe (≥ 500 mg/dL) hypertriglyceridemia, and outside the US, in combination with other drugs to prevent heart attacks. This was the first class of fish oil-based drug to be approved for use as a drug. The first approvals came in Europe in 2001 and the first approval in the US came in 2004. These fish oil drugs are similar to fish oil dietary supplements but the ingredients are better controlled and have been tested in clinical trials.