[Multicenter, double-blind study of oral acetylcysteine vs. placebo]

The mucolytic activity of acetylcysteine (NAC) was evaluated in a double-blind, placebo controlled, clinical trial performed in three pneumology centres and involving a total of 215 patients with the following diagnoses: 84 acute bronchitis, 95 superinfections of chronic bronchitis, 36 complicated bronchitis in patients with severe chronic respiratory insufficiency. Treatment consisted of 1 sachet of 200 mg NAC t.i.d. for 10 days. Standard antibiotic therapy (amoxycillin 1.5 g/day) was concurrently administered for 7 days. Statistical analysis comparing sputum volume and viscosity, sedation of cough and improvement of PEFR in 108 NAC and in 107 placebo treated patients, showed that NAC was very significantly more effective than placebo. The effect of NAC was negligible in the 36 patients with complicated bronchitis, whereas it was evident and remarkable in patients with acute and chronic bronchitis.