Niacin: an old drug rejuvenated.

Niacin has long been used in the treatment of dyslipidemia and cardiovascular disease. Recent research on niacin has been focused on understanding the mechanism of action of niacin and preparation of safer niacin formulations. New findings indicate that niacin does the following: 1) it inhibits hepatic diacylglycerol acyltransferase 2, resulting in inhibition of triglyceride synthesis and decreased apolipoprotein B-containing lipoproteins; 2) it decreases the surface expression of hepatic adenosine triphosphate synthase beta-chain, leading to decreased holoparticle high-density lipoprotein catabolism and increased high-density lipoprotein levels; and 3) it increases redox potential in arterial endothelial cells, resulting in inhibition of redox-sensitive genes. Flushing, an adverse effect of niacin, results from niacin receptor GPR109A-mediated production of prostaglandin D2 and E2 via DP1 and EP2/4 receptors. DP1 receptor antagonist (laropiprant) attenuates the niacin flush. A reformulated preparation of extended-release niacin (Niaspan; Abbott, Abbott Park, IL) lowers flushing compared with an older Niaspan formulation. These advancements in niacin research have rejuvenated its use for the treatment of dyslipidemia and cardiovascular disease.