N-acetylcysteine in patients with COPD exacerbations associated with increased sputum.

Background: N-acetylcysteine (NAC) has been shown not to alter the clinical outcome in chronic obstructive pulmonary disease (COPD) exacerbations. However, NAC may improve symptoms through its mucolytic effect in the subgroup of patients with increased sputum production. The aims of this study were to determine whether NAC improves symptoms and pulmonary function in patients with COPD exacerbation and increased sputum production.

Methods: This was a placebo-controlled study, where patients with severe COPD and increased sputum production, who were hospitalized for an exacerbation, were included. They were randomized to receive either NAC 200 mg tid or placebo in addition to the usual treatment.

Results: Forty-two patients were included and were equally distributed to NAC and placebo groups. The symptoms, namely, ease of sputum production and dyspnea at rest and on exertion significantly improved in both groups; but there was no difference in improvement between NAC and placebo groups (p = 0.96, 0.62, 0.31, respectively). Similarly, forced expiratory volume-one second (FEV1) and PaO2 levels improved significantly in NAC (964 ± 599-1239 ± 543 ml, p < 0.001, and 57.5 ± 14.5-70.5 ± 16.0 mmHg, p < 0.001, respectively) and placebo groups (981 ± 514-1180 ± 535 ml, p < 0.001 and 57.9 ± 14.3-68.7 ± 19.0 mmHg, p < 0.001, respectively), without any difference between the two groups (p = 0.52 and 0.57). There was no difference in the number of exacerbations during the 6-month follow-up period.

Conclusion: NAC does not have any beneficial effect on clinical outcomes in patients with severe COPD exacerbation associated with increased and/or viscous mucus production.