A comparison of 5 days of dirithromycin and 7 days of clarithromycin in acute bacterial exacerbation of chronic bronchitis.

The safety and efficacy of dirithromycin and clarithromycin were compared in a single-blind, multicentre study of patients with acute bacterial exacerbation of chronic bronchitis (AECB). Patients received either dirithromycin, 500 mg once daily for 5 days, or clarithromycin, 250 mg twice daily for 7 days. A total of 212 patients entered the study, of whom 191 qualified for efficacy analysis. Favourable post-therapy clinical and bacteriological response rates for qualified patients (95 dirithromycin and 96 clarithromycin) were similar: 89.5% and 68.8% for dirithromycin vs 94.8% and 71.9% for clarithromycin. At late post-therapy evaluation, favourable clinical and bacteriological response rates were achieved in 98.8% and 96.2% of dirithromycin patients and 95.3% and 93.3% of clarithromycin patients, respectively. These differences were neither statistically nor clinically significantly different. Both drugs had similar efficacy against Haemophilus influenzae and both were well tolerated. Dirithromycin, administered as a single daily dose for just 5 days resulted in complete compliance in all but four patients. In clarithromycin-treated patients, requiring a 7-day course of twice-daily treatment, compliance was less satisfactory, with 12 patients failing to comply, though the between-group difference was not statistically significant. It can be concluded that 5 days of dirithromycin, 500 mg once daily is as safe and effective as 7 days of clarithromycin, 250 mg, twice daily in the treatment of AECB.