Understanding niacin formulations.

Niacin is an important therapeutic option for the treatment of dyslipidemias and is the only agent currently available that favorably affects all components of the lipid profile to a significant degree. Niacin has consistently been shown to significantly reduce levels of total cholesterol, low-density lipoprotein (LDL) cholesterol, triglycerides, and lipoprotein (a), while having the greatest high-density lipoprotein (HDL) cholesterol-raising effects of all available agents. Niacin has also been shown to significantly reduce coronary events and total mortality. Niacin is available in 3 formulations: immediate-release (IR), sustained-release (SR), and a newer formulation, niacin extended-release (ER), all of which differ in their pharmacokinetic, efficacy, and safety profiles. Conventional niacin therapy has notable limitations that include flushing, most often seen with IR formulations, and hepatotoxicity, associated with SR formulations. These side effects are related to the absorption rate and subsequent metabolism of niacin as delivered from the different products. Niacin ER has a delivery system allowing absorption rates intermediate to that of niacin IR and SR. As a result, niacin ER achieves the efficacy of niacin IR with a reduced incidence of flushing and without the hepatic effects seen with niacin SR. The pharmacist should be familiar with the differences among and the advantages and disadvantages of each formulation to educate patients and help them achieve the optimal therapeutic benefit of niacin while minimizing adverse effects.