title: A multicenter, randomized, double-blind, retrospective comparison of 5- and 10-day regimens of levofloxacin in a subgroup of patients aged > or =65 years with community-acquired pneumonia.
abstract: OBJECTIVE
  This subgroup analysis sought to determine the efficacy and tolerability of a 5-day regimen of levofloxacin 750 mg/d compared with a 10-day regimen of levofloxacin 500 mg/d in the treatment of community-acquired pneumonia (CAP) in elderly patients (aged > or =65 years).
  
  
  METHODS
  This subgroup analysis was based on the outcomes in patients aged > or =65 years from a randomized, double-blind, controlled trial conducted at 70 US centers. Patients in Pneumonia Severity Index (PSI) class I/II and III/IV were randomized to receive levofloxacin 750 mg/d for 5 days or levofloxacin 500 mg/d for 10 days. Study investigators assessed clinical and microbiologic outcomes 7 to 14 days after administration of the last dose of medication and collected adverse events for 30 days after the last dose.
  
  
  RESULTS
  This analysis included 177 elderly patients, 80 receiving levofloxacin 750 mg/d for 5 days and 97 receiving levofloxacin 500 mg/d for 10 days. Although most demographic and baseline clinical characteristics were comparable between the 2 groups, the group that received levofloxacin 500 mg/d was older than the group that received levofloxacin 750 mg/d (median age, 76.0 vs 72.5 years, respectively; P = 0.029) and had a higher mean PSI score (90.7 vs 83.1; P = 0.017). Despite the halved duration of therapy, unadjusted clinical success rates were comparable between the 2 groups (89.0% and 91.9% in the 750- and 500-mg arms, respectively; 95% CI, -7.1 to 12.7). Microbiologic eradication rates were 90.3% (28/31) in the 750-mg arm and 87.5% (14/16) in the 500-mg arm (P = NS). Multivariate analysis adjusting for baseline PSI score indicated that treatment assignment was not statistically associated with clinical success (adjusted odds ratio for clinical success with 500-mg dose, 1.92; 95% CI, 0.62 to 5.99). The incidence of treatment-emergent adverse events did not differ between the 2 study treatments. The most common adverse events in both groups were insomnia, constipation, and headache.
  
  
  CONCLUSIONS
  This subgroup analysis found that levofloxacin 750 mg/d for 5 days was well tolerated in the treatment of CAP in elderly patients. Undajusted and adjusted rates of clinical success were statistically similar between levofloxacin 750 mg/d for 5 days and levofloxacin 500 mg/d for 10 days.
authors.affiliation: Pulmonary, Critical Care, and Sleep Medicine Service, Uniformed Services University of the Health Sciences, Bethesda, Maryland, USA. afshorr@dnamail.com
authors.forename: Andrew F
authors.initials: AF
authors.lastname: Shorr
authors.forename: Neringa
authors.initials: N
authors.lastname: Zadeikis
authors.forename: Jim X
authors.initials: JX
authors.lastname: Xiang
authors.forename: Alan M
authors.initials: AM
authors.lastname: Tennenberg
authors.forename: E
authors.initials: E
authors.lastname: Wes Ely
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D000900:Anti-Bacterial Agents / Q000008:administration & dosage / Q000627:therapeutic use*; D017714:Community-Acquired Infections / Q000145:classification / Q000188:drug therapy; D004311:Double-Blind Method; D004334:Drug Administration Schedule; D005260:Female; D006801:Humans; D064704:Levofloxacin; D008297:Male; D015337:Multicenter Studies as Topic; D015242:Ofloxacin / Q000008:administration & dosage / Q000627:therapeutic use*; D011014:Pneumonia / Q000145:classification / Q000188:drug therapy*; D016032:Randomized Controlled Trials as Topic; D012189:Retrospective Studies; D012720:Severity of Illness Index; D016896:Treatment Outcome
chemical_list: D000900:Anti-Bacterial Agents; D064704:Levofloxacin; D015242:Ofloxacin