Niacin, or vitamin B3, is beneficial in lowering LDL (bad) cholesterol and triglycerides while raising HDL (good) cholesterol. According to the American Heart Association, it is the most potent medicine for raising HDL cholesterol. It is available as a dietary supplement and usually sold as a gel capsule. Prescription-strength niacin is available in long-acting or extended-release formulations.
Flushing
Hot flashes, or a sudden sensation of heat "flushing" over the neck and face, are a common side effect of niacin therapy. The American Heart Association says it is not a serious side effect and taking an aspirin before taking the niacin can reduce it. Taking niacin at meal times or bedtime can also help. This side effect tends be worse with immediate-release over-the-counter supplements because the dose can vary considerably. Extended-release formulations tend to spread out the dose more evenly throughout the day, reducing the episodes and intensity of flushing. The good news is many people find that over time this side effect goes away.
Itching
A tingling, "pins and needles" or itching sensation is also a common side effect of niacin therapy. Although bothersome, it is not harmful and also tends to go away over time. In addition to taking niacin with a meal or at bedtime, avoiding hot drinks, and starting with low doses can also reduce the tingling sensations.
Rash
Some people may experience a rash associated with the flushing and itching, which may be a reason for decreasing the dose or discontinuing niacin.
Headache, Nausea, Dizziness
According to Medline Plus, if you experience headache, nausea and dizziness you should contact your doctor. Other side effects of niacin therapy that may be serious include fast heartbeat or yellowing of the skin.
Joint Pain
The American Heart Association also says that people with gout, which is a metabolic problem that results in a buildup of uric acid crystals in the joints, need to exercise caution in taking niacin because it can increase gout pain.
Increased Blood Sugar
Similarly, people with diabetes may need to modify the dose of niacin because it may produce an increase in sugar levels in blood and urine.
