Effect of combination lipid-modifying therapy on the triglyceride lowering effect of fish oil.

Background: Marine fish oil supplements are frequently administered with other lipid medications for treatment of hypertriglyceridemia. The efficacy of fish oil may be reduced in the presence of other lipid agents, particularly fibrates that also act as PPARalpha agonists. We therefore sought to determine the efficacy of fish-oil supplements when coadministered with other lipid-modifying agents.

Methods: Patients receiving fish oil supplements were identified from the computer database of a large governmental HMO. Change in plasma lipoprotein levels after administration of fish oil was compared between patients receiving fish oil as their only treatment and those for whom fish oil was added to other drugs.

Results: A total of 166 evaluable records were identified, 66 from patients treated with fish oil alone and 100 from patients for whom fish oil was added to another agent or other agents. Fish oil effectively reduced triglyceride levels to an equal extent in the fish oil only and fish oil added groups (-30% versus -27% respectively; P = 0.84).

Conclusion: Fish oil effectively reduces plasma triglyceride levels when administered with concomitant lipid medications. These findings suggest the presence of additional and even complementary mechanisms of action of fish oil to lower triglyceride when added to other lipid drugs. These findings validate the common clinical practice of combining fish oil supplements with other lipid-lowering medications in patients with hypertriglyceridemia.