Niacin (nicotinic acid) in large amounts has been used to decrease low-density lipoprotein (LDL) cholesterol and triglyceride levels and to increase high-density lipoprotein (HDL) cholesterol levels. Symptoms may include flushing and, rarely, hepatotoxicity.
Niacin derivatives include nicotinamide adenine dinucleotide (NAD) and nicotinamide adenine dinucleotide phosphate (NADP), which are coenzymes in oxidation-reduction reactions. They are vital in cell metabolism.
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Immediate- and sustained-release preparations of niacin (but not nicotinamide) may affect lipid levels. Despite lowering LDL levels, niacin supplements have shown no benefit in terms of reducing cardiovascular disease; because niacin supplementation is also associated with an increase in adverse events, it is no longer recommended ((but not nicotinamide) may affect lipid levels. Despite lowering LDL levels, niacin supplements have shown no benefit in terms of reducing cardiovascular disease; because niacin supplementation is also associated with an increase in adverse events, it is no longer recommended (1, 2).
High doses of niacin (3000 mg/day) may cause jaundice, abdominal discomfort, blurred vision, worsening of hyperglycemia, and precipitation of preexisting gout. High-dose High doses of niacin (3000 mg/day) may cause jaundice, abdominal discomfort, blurred vision, worsening of hyperglycemia, and precipitation of preexisting gout. High-doseniacin has the potential to cause complications among people with a liver disorder.
Flushing, which is prostaglandin-mediated, is more common with immediate-release preparations. It may be more intense after alcohol ingestion, aerobic activity, sun exposure, and consumption of spicy foods. Flushing is minimized if niacin is taken after meals or if aspirin (325 mg, which may work better than lower doses) is taken 30 to 45 minutes before is taken after meals or if aspirin (325 mg, which may work better than lower doses) is taken 30 to 45 minutes beforeniacin. The chance of severe flushing can be reduced by starting immediate-release niacin at a low dose (eg, 50 mg 3 times a day) and increasing it very slowly. . The chance of severe flushing can be reduced by starting immediate-release niacin at a low dose (eg, 50 mg 3 times a day) and increasing it very slowly.
Hepatotoxicity may be more common with some sustained-release preparations. Some authorities recommend checking levels of uric acid, blood glucose, and plasma aminotransferases every 6 to 8 weeks until the dose of niacin has been stabilized.
References
1. HPS2-THRIVE Collaborative Group, Landray MJ, Haynes R, et al. Effects of extended-release niacin with laropiprant in high-risk patients. . Effects of extended-release niacin with laropiprant in high-risk patients.N Engl J Med. 2014;371(3):203-212. doi:10.1056/NEJMoa1300955
2. Ferrell M, Wang Z, Anderson JT, et al. A terminal metabolite of niacin promotes vascular inflammation and contributes to cardiovascular disease risk. . A terminal metabolite of niacin promotes vascular inflammation and contributes to cardiovascular disease risk.Nat Med. 2024;30(2):424-434. doi:10.1038/s41591-023-02793-8
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