• A Anzueto, C L Fisher, T Busman, and C A Olson.
• Division of Pulmonary Diseases/Critical Care Medicine, University of Texas Health Science Center at San Antonio, 78284-7885, USA. anzueto@uthscsa.edu
• Clin Ther. 2001 Jan 1;23(1):72-86.

BackgroundClarithromycin has established efficacy and safety in the treatment of respiratory infections.ObjectiveThis study examined the efficacy and safety of a new extended-release formulation of clarithromycin compared with amoxicillin/clavulanate in the treatment of acute exacerbation of chronic bronchitis (AECB).MethodsThis phase IIIB, multicenter, randomized, parallel-group, investigator-blinded study in patients with AECB and productive cough with purulent sputum compared treatment with extended-release clarithromycin (two 500-mg tablets once daily for 7 days) and amoxicillin/clavulanate (one 875-mg tablet twice daily for 10 days). Assessments were performed before treatment, between study days 10 and 12 (or within 48 hours after premature discontinuation), and between study days 17 and 21 (test of cure).ResultsOf 287 patients randomized and treated, 270 were clinically evaluable (137 clarithromycin, 133 amoxicillin/clavulanate). Treatment groups were well matched in terms of demographic characteristics, medical condition, and history. Among clinically evaluable patients at test of cure, 85% and 87% of clarithromycin- and amoxicillin/clavulanate-treated patients, respectively, demonstrated clinical cure (as defined in 1998 draft US Food and Drug Administration guidelines); among clinically and bacteriologically evaluable patients, 92% versus 89%, respectively, demonstrated bacteriologic cure. Overall pathogen eradication rates were similar in the 2 groups (88% clarithromycin, 89% amoxicillin/clavulanate). Rates of premature discontinuation of study drug for any reason differed between treatments: 3% (4/142) of clarithromycin-treated patients versus 12% (17/145) of amoxicillin/clavulanate-treated patients (P = 0.005). One percent (2/142) and 6% (8/145) of the respective treatment groups discontinued study drug because of adverse events. Adverse events generally occurred with a similar frequency in the 2 groups; however, taste alteration was more common with clarithromycin (9/142 [6%]) than with amoxicillin/clavulanate (1/145 [1%]; P = 0.01). Mean severity scores for gastrointestinal adverse events showed a significant difference between groups (1.16 for clarithromycin-treated patients and 1.58 for amoxicillin/clavulanate-treated patients: P = 0.016).ConclusionsThe results of this study demonstrate the clinical and bacteriologic equivalence and improved gastrointestinal tolerability of a 7-day course of once-daily extended-release clarithromycin relative to a 10-day course of twice-daily amoxicillin/clavulanate in the treatment of AECB.

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