Objective: To compare the efficacy, safety, and tolerability of azithromycin and amoxicillin in the treatment of patients with infectious exacerbation of chronic obstructive pulmonary disease. Methods: This study was conducted at six medical centers across Brazil and included 109 patients from 33 to 82 years of age. Of those, 102 were randomized to receive either azithromycin (500 mg/day for three days, n = 49) or amoxicillin (500 mg every eight hours for ten days, n = 53). The patients were evaluated at the study outset, on day ten, and at one month. Based on the clinical evaluation of the signs and symptoms present on day ten and at one month, the outcomes were classified as cure, improvement, or treatment failure. The microbiological evaluation was made through the culture of sputum samples that were considered appropriate samples only after leukocyte counts and Gram staining. Secondary efficacy evaluations were made in order to analyze symptoms (cough, dyspnea, and expectoration) and pulmonary function. Results: There were no differences between the groups treated with azithromycin or amoxicillin in terms of the percentages of cases in which the outcomes were classified as cure or improvement: 85% vs. 78% (p = 0.368) on day ten; and 83% vs. 78% (p = 0.571) at one month. Similarly, there were no significant differences between the two groups in the secondary efficacy variables or the incidence of adverse effects. Conclusion: Azithromycin and amoxicillin present similar efficacy and tolerability in the treatment of acute exacerbation of chronic obstructive pulmonary disease.

Keywords: Amoxicillin/therapeutic use; Azithromycin/therapeutic use; Bronchitis, chronic/drug therapy;