title: Penetration of intravenous and oral ciprofloxacin into sterile and empyemic human pleural fluid.
abstract: OBJECTIVE
  To compare the penetration of oral and intravenously administered ciprofloxacin into infected (empyemic) and noninfected (sterile) human pleural fluid.
  
  
  METHODS
  Eleven men and 5 women (aged 29-76) were consecutively selected from adult patients referred to the respiratory unit for pleural effusion. In this open-label, prospective trial, 13 patients with sterile pleural effusions were nonrandomly assigned to receive either ciprofloxacin 200 mg (single intravenous dose), 750 mg (single oral dose), or 750 mg (two oral doses per day for 3 days); 3 patients with infected pleural effusions received 750 mg oral doses for 10 days. Simultaneous pleural fluid and venous blood specimens were drawn over 5 hours after single dose or when steady-state was attained, and ciprofloxacin concentrations were measured by HPLC.
  
  
  RESULTS
  Pleural fluid concentrations of ciprofloxacin equaled plasma concentrations 1.5 hours after 200 mg was given intravenously and the pleural/plasma ratio remained > or = 0.9 for 4 hours. After a single 750-mg oral dose, pleural ciprofloxacin concentrations rose from 0 to 1.4 micrograms/mL over 5 hours with the highest pleural fluid/plasma ratio (0.7) at 5 hours. Average steady-state ciprofloxacin concentrations in sterile pleural fluid after 750 mg administered twice daily for 3 days, ranged between 1.1 and 1.8 micrograms/mL with ratios between 0.3 and 0.9 over 4 hours. In empyemic pleural fluid at the same dosage, average steady-state ciprofloxacin concentrations ranged between 1.9 and 3.4 micrograms/mL with ratios between 1.0 and 2.0 over 5 hours.
  
  
  CONCLUSIONS
  Oral ciprofloxacin penetrates into sterile and empyemic pleural fluid with concentrations 30-90 percent and 100-200 percent of plasma concentrations, respectively.
authors.affiliation: Division of Pulmonary and Critical Care Medicine, College of Medicine, Medical University of South Carolina, Charleston.
authors.forename: J
authors.initials: J
authors.lastname: Joseph
authors.forename: L M
authors.initials: LM
authors.lastname: Vaughan
authors.forename: G S
authors.initials: GS
authors.lastname: Basran
mesh_terms: D000284:Administration, Oral; D000328:Adult; D000368:Aged; D002939:Ciprofloxacin / Q000008:administration & dosage / Q000493:pharmacokinetics*; D016724:Empyema, Pleural / Q000378:metabolism*; D005260:Female; D006801:Humans; D007262:Infusions, Intravenous; D008297:Male; D008875:Middle Aged; D010996:Pleural Effusion / Q000378:metabolism*; D011446:Prospective Studies
chemical_list: D002939:Ciprofloxacin