Cochrane for Clinicians

Putting Evidence into Practice

Role of Mucolytics in the Treatment of Chronic Bronchitis or COPD


Am Fam Physician. 2020 Jul 1;102(1):16-17.

Author disclosure: No relevant financial affiliations.

Clinical Question

Are oral mucolytics safe and effective at reducing the number of acute exacerbations, days of disability, and hospital admissions in patients with chronic bronchitis or chronic obstructive pulmonary disease (COPD)?

Evidence-Based Answer

Oral mucolytic agents may reduce the number of acute exacerbations in patients with chronic bronchitis or COPD (number needed to treat [NNT] = 8 over an average of nine months; 95% CI, 7 to 10). Although mucolytics do not appear to impact lung function or quality of life, they are associated with a small reduction in days of disability per month (mean difference [MD] = −0.43 days; 95% CI, −0.56 to −0.30) and decreased hospital admissions (NNT for 17 months = 19; 95% CI, 12 to 59). Mucolytics are not associated with an increase in adverse effects.1 (Strength of Recommendation: B, based on inconsistent or limited-quality patient-oriented evidence.)

Practice Pointers

COPD is the fourth leading cause of death in the United States, with the majority of cases attributed to tobacco use.1,2 COPD is characterized by persistent respiratory symptoms and chronic airflow limitation due to a mixture of small airway disease and parenchymal destruction.3 Current clinical practice guidelines require spirometry to establish the diagnosis of COPD.3 Many patients with chronic bronchitis have COPD. Acute exacerbations are the largest contributor to health care costs related to COPD and are characterized by an increase in the volume or purulence of sputum.1 The authors of this review sought to determine the potential role of mucolytics in the treatment of chronic bronchitis or COPD.

This Cochrane review included 38 randomized controlled trials (published between 1976 and 2017) involving 10,377 participants.1 The authors looked for placebo-controlled trials investigating a range of oral mucolytic therapy given for at least two months in adults with chronic bronchitis or COPD. The mean age of participants ranged from 40 years to 71 years.

Author disclosure: No relevant financial affiliations.


show all references

1. Poole P, Sathananthan K, Fortescue R. Mucolytic agents versus placebo for chronic bronchitis or chronic obstructive pulmonary disease. Cochrane Database Syst Rev. 2019;(5):CD001287....

2. Centers for Disease Control and Prevention. Disease of the week. COPD. Updated November 5, 2019. Accessed November 8, 2019.

3. Global Initiative for Chronic Obstructive Lung Disease. Global strategy for the diagnosis, management, and prevention of chronic obstructive pulmonary disease (2019 report). Accessed October 30, 2019.

4. Definition and classification of chronic bronchitis for clinical and epidemiological purposes. A report to the Medical Research Council by their Committee on the Aetiology of Chronic Bronchitis. Lancet. 1965;1(7389):775–779.

5. National Institute for Health and Care Excellence. Chronic obstructive pulmonary disease in over 16s: diagnosis and management. NICE guideline [NG115]. Updated July 2019. Accessed October 30, 2019.

6. Wedzicha JA, Calverley PMA, Albert RK, et al. Prevention of COPD exacerbations: a European Respiratory Society/American Thoracic Society guideline. Eur Respir J. 2017;50(3):1602265.

7. Criner GJ, Bourbeau J, Diekemper RL, et al. Prevention of acute exacerbations of COPD: American College of Chest Physicians and Canadian Thoracic Society guideline. Chest. 2015;147(4):894–942.

8. Department of Veterans Affairs, Department of Defense. VA/DoD clinical practice guideline for the management of chronic obstructive pulmonary disease. December 2014. Accessed October 30, 2019.

These are summaries of reviews from the Cochrane Library.

This series is coordinated by Corey D. Fogleman, MD, assistant medical editor.

A collection of Cochrane for Clinicians published in AFP is available at



Copyright © 2020 by the American Academy of Family Physicians.
This content is owned by the AAFP. A person viewing it online may make one printout of the material and may use that printout only for his or her personal, non-commercial reference. This material may not otherwise be downloaded, copied, printed, stored, transmitted or reproduced in any medium, whether now known or later invented, except as authorized in writing by the AAFP. Contact for copyright questions and/or permission requests.

Want to use this article elsewhere? Get Permissions

More in Pubmed


Jan 2022

Access the latest issue of American Family Physician

Read the Issue

Email Alerts

Don't miss a single issue. Sign up for the free AFP email table of contents.

Sign Up Now

Navigate this Article