Macrolide antibiotics such as azithromycin have anti-inflammatory properties as well as antimicrobial and antiviral effects. Reports suggesting that macrolide antibiotics might be beneficial to asthma patients have arisen regularly over the years but have tended to be contradictory leading to a lack of conviction in this possibility.
The authors of this new paper have attempted to strengthen the evidence that supports the use of azithromycin by designing a double blinded clinical trial with reasonable (420) sample size and running the trial over 48 weeks. Consequently the result has high statistical strength and finds that there is a reduction of one quarter (61% down to 44%) of the number of people having at least one asthma exacerbation per patient year (probability of this result being due to chance <0.0001).
Patients on azithromycin had 1.07 exacerbations per patient year compared with 1.86 exacerbations per patients year for the placebo, a 43% reduction in exacerbations.
Quality of Life scores (a measure derived directly from patients own opinions on how well they feel) were also significantly improved.
Importantly azithromycin is recommended for use as an add-on therapy for persistent asthma.