Comparative study of dirithromycin and azithromycin in the treatment of acute bacterial exacerbations of chronic bronchitis.

We compared the clinical and microbiological efficacy of dirithromycin with that of azithromycin in outpatients with acute bacterial exacerbations of chronic bronchitis who could be graded into stage III according to Ball's system of stratification. A total of 80 patients was studied. Of these, 40 were treated with dirithromycin as a once-daily dose of 500 mg for 5 days, and 40 with azithromycin as a once-daily dose of 500 mg for 3 days.