Niacin for dyslipidemia: considerations in product selection.

The efficacy and safety profiles of various forms of niacin for treating dyslipidemia are described. Niacin is well recognized for treating dyslipidemia in adults and has been shown to be effective in reducing coronary events. It has a broad range of effects on serum lipids and lipoproteins, including lowering total cholesterol, low-density-lipoprotein (LDL) cholesterol, and triglycerides. Niacin is the most effective lipid-modifying drug for raising high-density-lipoprotein (HDL) cholesterol levels and has been shown to lower Lp(a) lipoprotein. Niacin reduces triglycerides and very-low-density-lipoprotein and LDL cholesterol synthesis, primarily by decreasing fatty acid mobilization from adipose tissue. Niacin appears to raise HDL cholesterol by reducing hepatic apolipoprotein A-l clearance and enhancing reverse cholesterol transport. Niacin is metabolized through a conjugation or nicotinamide pathway. Standard immediate-release niacin is metabolized primarily through the conjugation pathway, which results in a high frequency of flushing. Long-acting niacin is metabolized through the nicotinamide pathway, which results in less flushing but increases the risk of hepatotoxicity. Extended-release niacin has a more balanced metabolism and causes fewer of both types of adverse effects. Improved serum lipid levels during niacin therapy have been associated with clinical and angiographic evidence of reduced coronary artery disease, especially when combined with statins. Niacin is particularly useful for managing high triglyceride and low HDL cholesterol levels as well as the lipid abnormalities associated with metabolic syndrome, including those commonly encountered in patients with diabetes. Several niacin products are available with significant differences in their safety and efficacy profiles. Health care providers must consider the differences between agents when recommending niacin for dyslipidemia treatment.