Mucolytics are oral medicines that increase expectoration of sputum byreducing its viscosity. Improved expectoration of sputum may lead to areduction in exacerbations of chronic obstructive pulmonary disease (COPD).

The purpose of new study published in The Cochrane Database ofSystemic Reviews were – to determine whether treatment with mucolyticsreduces exacerbations and/or days of disability in patients with chronicbronchitis or COPD; to assess whether mucolytics lead to improvement in lungfunction or quality of life; and to determine frequency of adverse effectsassociated with use of mucolytics. 

Here, the Cochrane Airways Group Specialised Register and referencelists of articles were searched on 12 separate occasions—most recently on 23April 2019. Randomized studies that compared oral mucolytic therapy versusplacebo for at least two months in adults with chronic bronchitis or COPD wereselected. Overall, this review included 38 trials, recruiting a total of 10 377participants. The studies selected, investigated mucolytics including –N-acetylcysteine, carbocysteine, erdosteine, and ambroxol, given at least oncedaily. 

Findings from 28 studies including 6 723 participants showed thatpatients receiving mucolytics may be more likely to be exacerbation-free duringthe study period compared to those given placebo. On the other hand, the typeor dose of mucolytic did not seem to alter the effect size, nor did theseverity of COPD, including exacerbation history. While longer studies depictedsmaller effects of mucolytics than were reported in shorter studies. Mucolyticuse was associated with a reduction of 0.43 days of disability per participantper month compared to the use of placebo. Additionally, the incidence ofhospitalizations was lower among the group receiving mucolytics –moderate-certainty evidence. Investigators reported improved quality of lifeand reduced adverse events with mucolytics. However, no clear difference wasnoted between mucolytics and placebo for mortality.

It was concluded that in participants with chronic bronchitis or COPD,treatment with mucolytics leads to a small reduction in the likelihood ofhaving an acute exacerbation, in days of disability per month and possiblyhospitalizations. 

Source:  The Cochrane Database of SystemicReviews. 2019 May 20;5(5):CD001287. doi:10.1002/14651858.CD001287.pub6.