title: Phase III, randomized, double-blind study of clarithromycin extended-release and immediate-release formulations in the treatment of patients with acute exacerbation of chronic bronchitis.
abstract: BACKGROUND
  Clarithromycin has an established efficacy and safety profile in the treatment of respiratory tract infections.
  
  
  OBJECTIVE
  The purpose of this study was to compare the clinical and bacteriologic efficacy and tolerability of clarithromycin extended-release and immediate-release formulations in patients with acute exacerbation of chronic bronchitis (AECB).
  
  
  METHODS
  In a phase III, randomized, double-blind, parallel-group, multicenter study. patients aged > or =12 years with signs and symptoms of AECB and a productive cough with purulent sputum received treatment with extended-release (two 500-mg tablets once daily) or immediate-release (one 500-mg tablet twice daily) clarithromycin for 7 days. Assessments were performed before treatment, within 48 hours after treatment, and at the test-of-cure visit (study days 19-21). Patients who took > or =1 dose of study drug were included in the safety analysis.
  
  
  RESULTS
  Of 620 patients randomized and treated, 182 were clinically and bacteriologically assessable (100 in the extended-release group and 82 in the immediate-release group). Treatment groups were well matched with respect to demographic characteristics and medical and social history. At the test-of-cure visit, 83% (83/100) of patients in the extended-release and 82% (67/82) of patients in the immediate-release group achieved clinical cure; 86% (85/99) and 85% (70/82), respectively, demonstrated bacteriologic cure. Overall pathogen eradication rates were 86% (100/116) in the extended-release group and 88% (86/98) in the immediate-release group. The most frequently reported adverse events were diarrhea (6% in extended-release group vs 4% in immediate-release group; no significant difference), taste alterations (4% in each group), and nausea (3% in each group); no clinically meaningful changes in laboratory values or vital signs, as assessed by the investigator, were observed.
  
  
  CONCLUSIONS
  This study suggests that clarithromycin extended-release and immediate-release formulations have equivalent clinical and bacteriologic efficacy and tolerability in patients with AECB.
authors.affiliation: Clinicos Clinical Research, Colorado Springs, Colorado 80904, USA.
authors.forename: J L
authors.initials: JL
authors.lastname: Adler
authors.forename: W
authors.initials: W
authors.lastname: Jannetti
authors.forename: D
authors.initials: D
authors.lastname: Schneider
authors.forename: J
authors.initials: J
authors.lastname: Zhang
authors.forename: R
authors.initials: R
authors.lastname: Palmer
authors.forename: G
authors.initials: G
authors.lastname: Notario
mesh_terms: D000208:Acute Disease; D000328:Adult; D000368:Aged; D000900:Anti-Bacterial Agents / Q000008:administration & dosage / Q000627:therapeutic use*; D001991:Bronchitis / Q000188:drug therapy* / Q000503:physiopathology; D002908:Chronic Disease; D017291:Clarithromycin / Q000008:administration & dosage / Q000627:therapeutic use*; D003692:Delayed-Action Preparations; D004311:Double-Blind Method; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D010349:Patient Compliance
chemical_list: D000900:Anti-Bacterial Agents; D003692:Delayed-Action Preparations; D017291:Clarithromycin