Among patients with the lung disorder non-cystic fibrosis bronchiectasis, treatment with the antibiotic azithromycin or erythromycin resulted in improvement in symptoms but also increased the risk of antibiotic resistance, according to two studies appearing in the March 27, 2013 issue of JAMA.

Macrolide antibiotics have antibacterial and anti-inflammatory properties that can provide effective treatment of bronchiectasis, an obstructive lung disease that can cause recurrent lung infections, a disabling cough, shortness of breath, and potential respiratory failure. The macrolide antibiotics have been shown beneficial in treating cystic fibrosis (CF), and findings from small studies suggest a benefit in non-CF bronchiectasis, according to researchers.

First Study: Azithromycin

Scientists from the Netherlands conducted a multicenter, randomized, placebo-controlled trial in 14 hospitals among 83 outpatients with non-CF bronchiectasis and 3 or more lower respiratory tract infections in the preceding year. As part of the study, 43 participants received azithromycin and 40 received a placebo.

A total of 117 exacerbations treated with antibiotics were reported during one year of treatment, two-thirds (78) of which occurred in the placebo group. Eighty percent of participants (32 out of 40) receiving placebo had at least one exacerbation during the study period. Meanwhile, only 46.5% of participants (20 out of 43) receiving azithromycin had at least one exacerbation.

“We conclude that macrolide maintenance therapy was effective in reducing exacerbations in patients with non-CF bronchiectasis,” the authors wrote. “In this trial, azithromycin treatment resulted in improved lung function and better quality of life but involved an increase in gastrointestinal adverse effects and high rates of macrolide resistance.”

Second Study: Erythromycin

Meanwhile, an additional randomized controlled trial looked at the benefits of erythromycin for adult patients with non-CF bronchiectasis with a history of two or more infective exacerbations in the preceding year.

A total of 117 patients received twice-daily erythromycin ethylsuccinate (400 mg) or matching placebo. Researchers found that erythromycin significantly reduced protocol-defined pulmonary exacerbations (PDPEs), with total of 76 for the erythromycin group vs 114 for the placebo group., according to the study.

“Erythromycin reduced 24-hour sputum production and [lessened] lung function decline compared with placebo. Erythromycin increased the proportion of macrolide-resistant oropharyngeal streptococci,” wrote lead author David J. Serisier, MBBS, DM, of Mater Adult Hospital in South Brisbane, Australia.

“In conclusion, long-term low-dose erythromycin significantly reduced exacerbations, protected against lung function decline, reduced sputum production, and significantly increased macrolide resistance in oropharyngeal streptococci.”