Randomized, multicentre study of the efficacy and tolerance of azithromycin versus clarithromycin in the treatment of adults with mild to moderate community-acquired pneumonia. Azithromycin Study Group

Eur J Clin Microbiol Infect Dis. 1998 Dec;17(12):828-33. doi: 10.1007/s100960050201.


Adults with mild to moderate community-acquired pneumonia were treated with azithromycin (500 mg once daily for 3 days) or clarithromycin (250 mg twice daily for 10 days) and clinically assessed between days 3 and 7 and days 12 and 16. Patients classified as improved at the day 12-16 visit were also evaluated between days 19 and 23. Two hundred three patients were treated (101 with azithromycin, 102 with clarithromycin). A satisfactory clinical response was recorded at the end of therapy in 83 of 88 (94%) evaluable azithromycin-treated and 84 of 88 (95%) evaluable clarithromycin-treated patients (P=0.518). At day 19-23, only one patient in each treatment group had relapsed. Thirty-one of 32 (97%) pathogens isolated from patients in the azithromycin group were eradicated, compared with 32 of 35 (91%) isolated from clarithromycin patients. In all patients with atypical pneumonia, the clinical response was satisfactory at follow-up. Incidences of treatment-related adverse events were similar for the two groups (P=0.815). Two (2%) clarithromycin patients discontinued therapy due to severe treatment-related adverse events; none in the azithromycin group did. This study shows that a 3-day, once-daily course of azithromycin is as clinically effective and well tolerated as a 10-day, twice-daily course of clarithromycin in the treatment of mild to moderate community-acquired pneumonia.

Publication types

  • Clinical Trial
  • Comparative Study
  • Multicenter Study
  • Randomized Controlled Trial
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adolescent
  • Adult
  • Aged
  • Anti-Bacterial Agents / therapeutic use*
  • Azithromycin / therapeutic use*
  • Clarithromycin / therapeutic use*
  • Community-Acquired Infections / drug therapy
  • Female
  • Humans
  • Male
  • Middle Aged
  • Pneumonia, Bacterial / drug therapy*
  • Pneumonia, Bacterial / microbiology
  • Treatment Outcome


  • Anti-Bacterial Agents
  • Azithromycin
  • Clarithromycin