Effects of S-carboxymethylcysteine on tracheal mucus velocity.

The effects of S-carboxymethylcysteine on tracheal mucus velocity were assessed in a double blind crossover study between 2 grams S-carboxymethylcysteine and placebo. Subjects included six healthy non-smokers, eight smokers with small airway disease and chronic simple bronchitis, and eight subjects with chronic obstructive bronchitis. Tracheal mucus velocity was measured prior to and two and three hours after each subject had ingested S-carboxymethylcysteine or placebo. No significant change in tracheal mucus velocity occurred after placebo or S-carboxymethylcysteine in any of the groups, indicating that the drug has no acute effect on mucus transport.