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 compar ed the efficacy and tolerability of clarithromycin modified release (MR) wi th those of amoxicillin/clavulanic acid in 250 adult outpatients with acute exacerbation of chronic bronchitis (AECB). Patients received either clarit hromycin MR 500 mg once daily or amoxicillin/clavulanic acid 500 mg/125 mg three times daily for 7 days. Primary endpoints were sponsor-defined clinic al response and pathogen outcome at the end of treatment. Secondary endpoin ts were sponsor-defined clinical response and pathogen outcome at study end , investigator-defined clinical response at end of treatment and end of stu dy, resolution or improvement of signs and symptoms, eradication of baselin e pathogens, serologic outcome for atypical pathogens, and occurrence of re infection and superinfection. Adverse events and compliance were also evalu ated. Clinical and bacteriologic outcomes with both treatments for all endp oints 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 s ignificantly higher with amoxicillin/clavulanic acid. Ninety-five percent o f patients receiving clarithromycin MR and 80% receiving amoxicillin/clavul anic 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.