A comparative study of clarithromycin modified release and amoxicillin/clavulanic acid in the treatment of acute exacerbation of chronic bronchitis

This phase III, investigator-blind, randomized, parallel-group study compared the efficacy and tolerability of clarithromycin modified release (MR) with those of amoxicillin/clavulanic acid in 250 adult outpatients with acute exacerbation of chronic bronchitis (AECB). Patients received either clarithromycin MR 500 mg once daily or amoxicillin/clavulanic acid 500 mg/125 mg three times daily for 7 days. Primary endpoints were sponsor-defined clinical response and pathogen outcome at the end of treatment. Secondary endpoints were sponsor-defined clinical response and pathogen outcome at study end, investigator-defined clinical response at end of treatment and end of study, resolution or improvement of signs and symptoms, eradication of baseline pathogens, serologic outcome for atypical pathogens, and occurrence of reinfection and superinfection. Adverse events and compliance were also evaluated. Clinical and bacteriologic outcomes with both treatments for all endpoints were statistically equivalent, as were total adverse events, although the incidences of digestive disturbances (13% vs 4%) and discontinuations due to adverse events (8 vs 2 patients; P less than or equal to .05) were significantly higher with amoxicillin/clavulanic acid. Ninety-five percent of patients receiving clarithromycin MR and 80% receiving amoxicillin/clavulanic acid were 100% compliant with medication (P less than or equal to .05). Clarithromycin MR and amoxicillin/clavulanic acid are both well tolerated and effective as therapy for AECB; however, clarithromycin produced fewer side effects and discontinuations and higher compliance rates.