People with uncontrolled asthma can significantly slash their number of exacerbations by adding azithromycin to their treatment regimen, Australian research shows.

Published in The Lancet by Professor Peter Gibson and colleagues from the Hunter Medical Research Institute in Newcastle, NSW, the AMAZES study involved 420 people with uncontrolled asthma who were randomised to oral azithromycin 500mg three times a week (n=213) or placebo (n=207).

At 48 week follow up patients who took azithromycin had fewer asthma exacerbations compared with placebo (1.07 vs 1.86 per year).

They also had fewer severe exacerbations requiring corticosteroids or hospitalisation (0.61 vs 1.07 per year), improved asthma control and asthma related quality of life.

The antibiotic macrolide was also associated with fewer respiratory tract infections, but rates of diarrhoea were higher with azithromycin compared to placebo (34% vs 19%).

“Using azithromycin in addition to inhaled corticosteroids and long-acting bronchodilators could substantially improve the health of people with uncontrolled persistent asthma,” the study authors concluded.

However, they noted that while azithromycin was a “valuable addition to existing regimens for treating asthma”, the potential impact of antimicrobial resistance was an “important barrier to the long-term use of macrolides for airway diseases”.

In an accompanying editorial Professor Guy Bruselle from Ghent University Hospital in Belgium and Professor Ian Pavord from Nuffield Department of Medicine in Oxford, UK, advised that to minimise microbial resistance add-on therapy with azithromycin should be restricted to patients with frequent exacerbations at time periods with the greatest risk of exacerbations, such as winter.

“Future studies with potentially safer non-antibiotic macrolides in uncontrolled severe asthma are warranted,” they added.