The Effects of Azithromycin in Treatment-Resistant Cough: A Randomized, Double-Blind, Placebo-Controlled Trial.

BACKGROUND: Chronic cough is a common clinical problem worldwide. Although many patients have underlying precipitating conditions such as asthma, gastroesophageal reflux, or rhinitis, many remain symptomatic despite treating these conditions. New approaches are needed for the treatment of this group of patients.

METHODS: We conducted a randomized, double-blind, placebo-controlled trial to determine whether 250 g of azithromycin three times a week for 8 weeks would affect the Leicester Cough Questionnaire (LCQ) score in 44 patients with treatment-resistant cough. Cough severity on a visual analog scale and bronchial exhaled nitric oxide were measured as secondary outcomes.

RESULTS: There was a clinically important improvement in LCQ score with azithromycin (mean change, 2.4; 95% CI, 0.5 to 4.2) but not placebo (mean change, 0.7; 95% CI, -0.6 to 1.9), but the between-group difference was not statistically significant (P = .12). There were no significant between-group differences for any of the secondary outcome measures. Looking at subgroups of responders, there was a large and significant improvement in LCQ score in patients with chronic cough and a concurrent diagnosis of asthma who were treated with azithromycin (mean, 6.19; 95% CI, 4.06 to 8.32).

CONCLUSIONS: Treatment with low-dose azithromycin for 8 weeks did not significantly improve LCQ score compared with placebo. The use of macrolides for treatment-resistant cough cannot be recommended from this study, but they may have a place in the treatment of chronic cough associated with asthma; this is worthy of further investigation.

TRIAL REGISTRY: WHO International Clinical Trials Registry; No.: ISRCTN75749391. URL: https://apps.who.int.