High-dose oral N-acetylcysteine fails to improve respiratory health status in patients with chronic obstructive pulmonary disease and chronic bronchitis: a randomized, placebo-controlled trial

• Type of Material: Article
• Authors: Kara Johnson, Minneapolis VA Health Care System; Charlene E. McEvoy, HealthPartners Research Foundation; Sakina Naqvi, Minneapolis VA Health Care System; Chris Wendt, Minneapolis VA Health Care System; Ronald A. Reilkoff, HealthEast Maplewood Clinic; Ken M. Kunisaki, Minneapolis VA Health Care System; Erin E. Wetherbee, Minneapolis VA Health Care System; David Nelson, Minneapolis VA Health Care System; Rabindra Tirouvanziam, Emory University; Dennis E. Niewoehner, Minneapolis VA Health Care System
• Language: English
• Date: 2016-04-21
• Publisher: Dove Medical Press
• Publication Version: Final Published Version
• Copyright Statement: © 2016 Johnson et al. This work is published and licensed by Dove Medical Press Limited.
• License: Creative Commons Attribution-Noncommercial 3.0 Unported
• Final Published Version (URL): http://dx.doi.org/10.2147/COPD.S102375
• Title of Journal or Parent Work: International Journal of Chronic Obstructive Pulmonary Disease
• ISSN: 1176-9106
• Start Page: 799
• End Page: 799
• Grant/Funding Information: The Minnesota Veterans Medical Research and Education Foundation, the HealthPartners Institute of Education and Research, and the University of Minnesota Graduate School provided financial support for the study.
• Keywords: N-acetylcysteine; COPD; chronic bronchitis
• Research Categories: Health Sciences, Pharmacology; Health Sciences, General

Abstract

Background Clinical outcomes are worse in patients with COPD and chronic bronchitis. N-acetylcysteine (NAC) is commonly prescribed for such patients but with uncertain clinical benefits. We postulated that oral NAC, at much larger doses than those ordinarily prescribed, would improve clinical outcomes in a subset of patients with COPD and chronic bronchitis. Objective The aim of this study was to determine whether very high-dose NAC would improve respiratory health status in patients with COPD and chronic bronchitis. Methods Patients with COPD and chronic bronchitis were enrolled in a randomized, controlled, double-blinded trial. Patients received oral NAC (1,800 mg) or matching placebo twice daily for 8 weeks in addition to their usual respiratory medications. The primary outcome, respiratory health status, was assessed by changes in the St George’s Respiratory Questionnaire. The effects of NAC on lung function and circulating markers of oxidative stress and inflammation were also evaluated. Results We terminated the study prematurely because new external information suggested the possibility of a safety issue. Of the planned 130 patients, 51 were randomized and 45 (22 in the placebo arm and 23 in the NAC arm) completed the study. There was no statistically significant difference between changes in the St George’s Respiratory Questionnaire total score, comparing NAC to placebo (adjusted mean difference, 0.1 U; 95% CI, −7.8 to 8.18 U; P=0.97). There were also no significant NAC-related improvements in any of the secondary outcomes. Conclusion In this 8-week trial, we were unable to show any clinical benefit from a very high dose of NAC in patients with COPD and chronic bronchitis.