Acute exacerbation of chronic bronchitis: expanding short-course therapy

Recent management guidelines for acute exacerbation of chronic bronchitis (AECB) have provided antimicrobial options for different classes of patients according to varying disease severity or risk of treatment failure. In a pivotal, double-blind, double-dummy study comparing azithromycin microspheres (2 g single dose) with the respiratory quinolone levofloxacin (500 mg once daily x 7 days) for the treatment of AECB, the two regimens were equally effective and well tolerated in patients with mild-to-moderate disease (clinical cure rate 93.6% vs. 92.7%, respectively [95% confidence interval (CI) for difference, -3.4, 5.5] and overall bacteriological eradication rate 91.9% vs. 94.4%, respectively (95% CI for difference, -8.8, 3.8). Interestingly, additional post hoc analyses suggest that a single dose of azithromycin also provides comparable clinical efficacy to levofloxacin in patients with a forced expiratory volume in 1 s (FEV1) of less than 70% of the predicted value, a risk factor that would place them in a more severe stratum. These data support azithromycin microspheres as an appropriate option in patients with mild-to-moderate AECB. The potential role of this preparation and other macrolides in patients at higher risk of therapeutic failure requires additional prospective data.