The Collaborative International Dictionary of English v.0.48:

niacinamide \niacinamide\ n.
   The amide of niacin (nicotinic acid), called also
   nicotinamide. It was at one time called vitamin B3, and
   can function to relieve nicotinic acid deficiency. Chemical
   formula C6H6N2O, chemically it is 3-pyridinecarboxamide.

   Syn: nicotinic acid amide, nicotinamide.
        [PJC]