Clinical efficacy of dirithromycin in acute exacerbations of chronic bronchitis.

The efficacy and safety of seven days treatment with oral dirithromycin 500 mg given once daily was compared with oral erythromycin 250 mg qid in patients with acute bacterial exacerbations of chronic bronchitis. A total of 393 patients received dirithromycin and 409 erythromycin. Of 101 dirithromycin-treated patients analysed for efficacy, 87 (86%) had favourable clinical responses compared with 72/81 (89%) of those treated with erythromycin. Proven or presumed pathogen elimination was noted in 85/101 (84%) dirithromycin-treated patients and 66/81 (82%) erythromycin treated patients. Late post-therapy responses were also similar between treatment groups. Favourable clinical responses were noted in 89% of patients treated with dirithromycin and 91% of those receiving erythromycin. A favourable bacteriological response was noted in 87.5% and 89.6% of the dirithromycin- and erythromycin-treated groups, respectively. Adverse events were also similar between treatment groups. Gastrointestinal events were the most common events in both groups of patients; erythromycin was associated with a significantly higher incidence of diarrhoea (P = 0.003). Dirithromycin was associated with a higher incidence of lung events (P = 0.043). It is concluded that dirithromycin given once a day is comparable in efficacy and safety to four-times-daily erythromycin in the treatment of acute bacterial exacerbations of chronic bronchitis.