Pharmacy Times

Reliant Pharmaceuticals' Omacor (omega-3-acid ethyl esters)

Author: Carolyn Soo, PharmD, and Phung Hoach

Coronary artery disease (CAD) is the most common type of heart disease, afflicting approximately 13 million people in the United States.1,2 Common risk factors include age, family history of heart disease, hypertension, obesity, diabetes, smoking, physical inactivity, and hypercholesterolemia.3 Specific lipid abnormalities, such as hypertriglyceridemia, also have been associated with CAD.

Although several options exist for treating lipid disorders, a pharmaceutical preparation of omega-3 polyunsaturated fatty acids (PUFAs) was approved by the FDA in November 2004.

Omacor, manufactured by Reliant Pharmaceuticals, is indicated to manage hypertriglyceridemia as an adjunct to diet. It also may be used as adjuvant therapy for secondary prevention in post-myocardial infarction (MI) patients.4

Pharmacology

Omacor is a lipid-regulating agent known as omega-3-acid ethyl esters. The ethyl esters are a combination of eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA). The mechanism of action is not clearly delineated, although a reduction in hepatic synthesis of triglycerides may be due to EPA and DHA because they are poor substrates for the enzymes responsible for triglyceride synthesis.4,5

Clinical Studies

A 1-year, double-blind, randomized trial examined the safety, tolerability, and effectiveness of omega-3 PUFAs in lowering triglycerides in patients with established coronary heart disease and persisting hypertriglyceridemia (serum triglycerides >2.3 mmol/L). Fifty-nine patients were enrolled and received either Omacor 2 g twice daily or placebo, in combination with simvastatin 10 to 40 mg daily. Serum triglycerides were significantly decreased by 20% to 30%, and very low-density lipoprotein cholesterol was reduced by 30% to 40%, in patients taking omega-3 PUFAs at 3, 6, and 12 months, compared with either baseline or placebo (P < .005). Overall, Omacor was well-tolerated by the participants.6

The GISSI-Prevenzione trial observed the effects of omega-3 PUFAs and vitamin E on morbidity and mortality in post- MI patients. The multicenter, open-label study enrolled approximately 11,400 patients with recent MIs (<3 months) to receive either 1 g of omega-3 PUFAs, 300 mg of vitamin E, either alone or in combination, versus standard care. The primary combined end point included the rate of all-cause death, the rate of cardiovascular death, nonfatal MI, and nonfatal stroke. The results demonstrated that treatment with omega-3 PUFAs only, through 4-way analysis, significantly lowered the risk of the primary end point, with a relative risk decrease of 15% (P = .023). In the combined-treatment group, cardiovascular death, nonfatal MI, and nonfatal stroke showed a relative decrease in risk of 20% (P = .008).7

Safety

The most common adverse events associated with Omacor include dyspepsia, flu-like symptoms, and taste distortion.4,5 Omacor may prolong bleeding time in patients taking anticoagulants, antiplatelets, salicylates, and nonsteroidal anti-inflammatory agents. Betablockers, estrogens, and thiazide diurectics may decrease the therapeutic effect of Omacor.4,5

Outlook

Omacor is available in 1-g gelatin soft capsules, with each gram containing roughly 900 mg of omega-3 ethyl esters—465 mg of EPA and 375 mg of DHA.4 The recommended daily dose for Omacor in the treatment of hypertriglyceridemia is 4 g per day as 1 single dose or in 2 divided doses.8 The 1-g, once-daily dose is recommended for the management of post-MI patients.8 Omacor appears to be a safe, effective, and tolerable option for lowering triglycerides and mortality rate in post- MI patients.

Dr. Soo is a senior research pharmacist with the Investigational Drug Service at Brigham and Women's Hospital, Boston, Mass. Ms. Hoach is a sixth-year PharmD candidate from Northeastern University, currently on clinical clerkship in the Investigational Drug Service at Brigham and Women's Hospital.

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