Effects of phenytoin, niacin, gemfibrozil, and omega-3 fatty acids on high density lipoproteins in patients with hypoalphalipoproteinemia

Background. Low levels of high density lipoprotein cholesterol (HDL-C) are a known risk factor for coronary artery disease (CAD). Several drugs are known to be able to raise HDL-C levels, but single study comparison of several drugs has rarely been made. Here we evaluated the effects of niacin, phenytoin, omega-3 fatty acids, and gemfibrozil on levels of HDL-C and its subfractions (HDL₂-C and HDL₃-C) in patients with low HDL-C levels. Methods. Fifty four patients with HDL-C ≤35 mg/dL were randomly assigned to 3 months of blinded treatment with one of four different drugs or placebo. Results. The statistically significant changes (vs. placebo) in HDL-C and triglycerides (TG) were as follows: niacin increased HDL-C by 28% (32 ± 6.3 to 40.8 ± 7.7 mg/dL; p=0.0001); increased HDL₃-C and HDL₂-C by 18% and 48%, respectively (p<0.0005); and decreased TG by 43.5% (203 ± 92 to 115 ± 36; p = 0.002). Phenytoin increased HDL₂-C by 16% (7.9 ± 2.2 to 9.2 ± 2.8; p = 0.004). Omega-3 fatty acids increased HDL₂-C by 19% (7.6 ± 1.6 to 9.0 ± 2.4; p = 0.018) and lowered TG by 24% (p = 0.02). Gemfibrozil raised both HDL-C by 17% (32.1 ± 3.7 to 37.4 ± 8.6, p = 0.02) and HDL₃-C by 17% (24.4 ± 3.5 to 28.5 ± 5.2; p<0.02). TG were reduced by 49% (p = 0.005). Conclusion. The most effective drug for low HDL-C in this group of patients was niacin. (C) 1999 by CHF, Inc.