NEW YORK — A combination of niacin and omega-3 fatty acids produced a dramatic drop in triglyceride levels and a large rise in HDL cholesterol levels in a controlled study in 14 patients with atherogenic dyslipidemia.
The combination was also effective in a separate study with seven patients who had type 2 diabetes, William L. Isley, M.D., said at an international symposium on triglycerides and HDL.
Although the combined use of the two over-the-counter (OTC) drugs is not approved by the Food and Drug Administration, both agents are safe and so the combination is worth trying in appropriate patients, said William S. Harris, Ph.D., professor of medicine at the University of Missouri-Kansas City and a coinvestigator on the study. Neither study received commercial support, he said.
The first study enrolled 14 patients without diabetes who had fasting serum triglyceride levels of 150–500 mg/dL, fasting HDL-cholesterol levels lower than 40 mg/dL in men or lower than 50 mg/dL in women, and normal LDL cholesterol levels. None of the participants was on any other lipid-lowering medication.
Seven patients were randomized to daily treatment with 1 g of immediate-release niacin t.i.d., and 3.4 g of omega-3 fatty acids. The other seven patients were treated with placebo. In this study, the fish oil formulation used was Omacor, a semipurified formulation that received FDA approval for prescription sale in the United States late last year.
After 16 weeks of treatment, patients in the active treatment arm had an average drop of 52% in their serum triglyceride levels, and an average rise in HDL cholesterol of 33%. In the placebo group, triglyceride levels rose by an average of 10%, and HDL cholesterol levels rose by an average of 4%, said Dr. Isley, an endocrinologist at the Mayo Clinic in Rochester, Minn.
Patients treated with the niacin and fish oil combination had a modest 6% rise in serum glucose, and an 11% rise in serum levels of LDL cholesterol.
The fall in triglycerides and rise in HDL cholesterol seen in this study were substantially greater than what's been seen with niacin treatment alone. In past studies, a niacin regimen produced a drop in triglyceride levels of about 20%–25%, and a boost in HDL cholesterol of about 15%, Dr. Harris told this newspaper at the symposium, which was sponsored by the Giovanni Lorenzini Medical Foundation.
The second study enrolled seven patients with type 2 diabetes in a crossover study that involved 16 weeks of treatment with the active combination and 16 weeks of treatment with placebo. In this study, the niacin regimen was the same as in the first study: 1 g of drug t.i.d. The fish oil dosage was 3.3 g of omega-3 fatty acids daily, administered as six capsules of an OTC formulation. Three patients remained on the statin regimen that they had been on when they entered the study.
Serum triglyceride levels averaged 238 mg/dL at baseline, and fell to an average of 114 mg/dL after 16 weeks of active treatment, a 52% drop. After 16 weeks of placebo treatment, the average serum triglyceride level was 233 mg/dL.
Serum levels of HDL cholesterol averaged 40 mg/dL at baseline, and rose to 63 mg/dL with active treatment, a 58% increase. After 16 weeks on placebo, the average HDL cholesterol level was 38 mg/dL.
During the study, patients showed no significant change in serum levels of LDL cholesterol or hemoglobin A1c.