Effervescent compositions containing N-acetylcysteine

An oral effervescent composition comprising at least 50% w/w of N-acetylcysteine, at least 20% w/w of a carbonate or bicarbonate salt, without an additional organic or inorganic acid, and from 3.5% to 15% w/w of a mixture of pharmaceutically acceptable excipients comprising a sweetener, a flavorant, and a diluent, wherein the oral effervescent composition results in an unit dose of N-acetylcysteine selected from the group consisting of 0.5 g, 1.0 g, 1.5 g, 2.0 g and 2.5 g.