Comparative safety and efficacy of clarithromycin and ampicillin in the treatment of out-patients with acute bacterial exacerbation of chronic bronchitis.

In an open, randomized trial, adult non-hospitalized patients with acute bacterial exacerbation of chronic bronchitis were treated with 500 mg clarithromycin twice daily (n = 53) or 500 mg ampicillin four times daily (n = 50). Causative pathogens included S. pneumoniae, M. catarrhalis, H. influenzae, H. parainfluenzae and S. aureus. For clinically evaluable patients, successful outcome (cure or improvement) was noted for 53/53 (100%) clarithromycin-treated patients and 46/47 (98%) ampicillin-treated patients. Clinically significant improvement in signs and symptoms was comparable between treatment groups. There was 100% bacteriological eradication in both treatment groups. Eight patients (15%) in the clarithromycin group and 10 patients (20%) in the ampicillin group reported adverse events, the majority of which were mild or moderate in severity; six events in each treatment group were digestive-system disorders. The new macrolide, clarithromycin, appears to be effective and well-tolerated in the treatment of acute exacerbation of chronic bronchitis.