Niacin affects all lipid parameters favorably. It is one of the only agents that reduces Lp (a) significantly (up to 30 per cent). Unfortunately, compliance is poor because of frequent side effects. Flushing and pruritus, gastrointestinal discomfort, glucose intolerance, and hyperuricemia often accompany use of niacin, hepatotoxicity is rare but is more commonly seen with the sustained released preparation. It is often heralded by a dramatic reduction in lipid levels. There are limited data on long-term therapy with this agent. Niacin may be particularly useful for patients who do not have substantial elevations in their LDL-C levels, and low doses may be used to treat diabetic dyslipidemia. High doses should be avoided in those with a history of gout, peptic ulcer disease, or active hepatic disease. Extended release preparations are to be used and not sustained release ones.