Prescription-strength niacin proves effective in improving your cholesterol levels, particularly HDL, or "good," cholesterol. But its ability to protect you against heart disease remains in doubt. All types of niacin may cause liver damage, and sustained-release niacin makes you more susceptible. You can incur other serious side effects from taking niacin, so discuss benefits and risks with your doctor before using.
Skin Flushes
Doctors may prescribe niacin in daily doses of up to 3,000 mg -- 3 g -- to help return your cholesterol to heart-healthy levels. If you take more than 100 mg of niacin a day, you may experience skin flushes. This harmless but uncomfortable condition makes your face and chest turn red, and your skin may itch, burn or tingle. Your doctor may prescribe sustained-release formulas to lessen the likelihood or severity of skin flushes. You can purchase over-the-counter formulas of sustained-release niacin. They will not treat cholesterol but will put you at risk of sustaining liver damage.
Liver Damage
If you take niacin, get your liver checked periodically. Liver damage most often occurs after prolonged use, but sometimes affects short-term users. The "Annals of Emergency Medicine" reports that a person who took large doses of over-the-counter niacin in an attempt to pass a drug-screening test required a liver transplant. M.K. Mittal, author of the report, published in April 2007, says that niacin -- regular or sustained-release -- does not help flush toxins out of your system, but poses serious dangers, including liver damage.
Other Side Effects
In addition to liver damage, side effects of taking sustained-release or regular niacin include headaches, nausea, vomiting and diarrhea. More serious side effects include irregular heartbeat, gout, gastrointestinal ulcers and vision loss. If you have kidney disease, taking niacin may make it worse. If you have type 2 diabetes, niacin may cause unhealthy elevations in your blood sugar levels. Such side effects may occur with both prescribed niacin and over-the-counter formulas containing niaicnamide. Some drugstore varieties of niacin contain inositol hexanicotinate. Both the benefits and risks of taking inositol hexanicotinate remain largely unknown.
Considerations
In May 2011, the National Institutes of Health prematurely ended a planned five-year study involving users of sustained-release niacin. Some participants in the study took statins, another cholesterol-lowering drug, and some took statins together with 2,000 mg daily of sustained-release niacin. Persons who took the combination of medications realized greater improvements in their cholesterol levels than persons who only took statins. But the niacin users suffered twice as many strokes and just as many heart attacks as participants who did not take niacin. The study ended 18 months earlier than planned.
References
- University of Maryland Medical Center; Vitamin B3 (Niacin); June 18, 2009
- MedlinePlus: Niacin and Niacinamide (Vitamin B3)
- National Institutes of Health; NIH Halts Clinical Trial on Combination Cholesterol Treatment; May 26, 2011
- CBC News; Niacin Trial For Heart Disease Stopped Early; May 27, 2011
- "Annals of Emergency Medicine"; Toxicity From the Use of Niacin to Beat Urine Drug Screening; Majoj Mittal et al.; April 6, 2007
- "Biotech Business Week"; Emergency Medicine -- Misusing Vitamin to Foil Drug Test May Be Toxic; Plus, It Doesn't Work; April 16, 2007
