Nicotinamide, (ni-kə-tē-nə-mīd) also known as
niacinamide and
nicotinic amide, is the
amide of
nicotinic acid (vitamin B
3 / niacin). Nicotinamide is a water-soluble
vitamin and is part of the
vitamin B group. Nicotinic acid, also known as
niacin, is converted to nicotinamide
in vivo, and, though the two are identical in their vitamin functions, nicotinamide does not have the same pharmacological and toxic effects of
niacin, which occur incidental to niacin's conversion. Thus nicotinamide does not reduce cholesterol or cause flushing, although nicotinamide may be toxic to the liver at doses exceeding 3 g/day for adults. In cells, niacin is incorporated into
nicotinamide adenine dinucleotide (NAD) and
nicotinamide adenine dinucleotide phosphate (NADP), although the pathways for nicotinic acid amide and nicotinic acid are very similar. NAD+ and NADP+ are
coenzymes in a wide variety of enzymatic
oxidation-reduction reactions. Commercial production of niacin and niacinamide (several thousand tons annually) is by hydrolysis or aminolysis of 3-cyanopyridine (nicotinonitrile).