Levofloxacin pharmacokinetics in adult cystic fibrosis

Chest. 2007 Mar;131(3):796-802. doi: 10.1378/chest.06-1524.


Background: Cystic fibrosis (CF) patients have enhanced renal clearance of aminoglycosides and several beta-lactams and require higher dosages. Levofloxacin is a fluoroquinolone with extensive renal elimination and enhanced penetration into lungs and Pseudomonas aeruginosa (PA) biofilms. We studied the preliminary pharmacokinetic and pharmacodynamic (PK/PD) relationship of levofloxacin in CF.

Methods: Twelve patients at least 18 years old with a mild-to-moderate pulmonary exacerbation and fluoroquinolone-sensitive PA colonization received oral levofloxacin, 500 mg qd, for 14 days. Steady-state serum concentrations were collected after 3 to 7 days, and sputum samples for PA densities were collected before and after levofloxacin. PK/PD relationships for reducing PA sputum densities were evaluated.

Results: When compared to published data on non-CF patients, CF patients had similar area under the curve for 24 h (AUC(24)), total clearance, volume of distribution, maximum serum concentration (Cpmax), and elimination half-life: mean, 7.33 microg x h/mL/kg (SD, 1.70); 2.43 mL/min/kg (SD, 0.74); 1.33 L/kg (SD, 0.37); 7.06 microg/mL (SD, 2.35); and 6.44 h (SD, 1.1), respectively. Time to reach maximum serum concentration (Tmax) in CF was longer: mean, 2.20 h (SD, 0.99) vs 1.1 h (SD, 0.4) [p < 0.01]. Preliminary PK/PD analysis failed to demonstrate trends for decreasing PA sputum densities with increasing Cpmax/minimum inhibitory concentration (MIC) ratio and AUC(24)/MIC ratio.

Conclusion: CF levofloxacin pharmacokinetics corrected for body weight are similar to non-CF, except for Tmax. Standard levofloxacin dosing (especially monotherapy) is unlikely to produce maximum therapeutic effectiveness. Additional levofloxacin studies in CF are necessary to evaluate its sputum concentrations; the benefits of higher daily dosages (>/= 750 mg); and establish PK/PD targets for managing PA pulmonary infections.

Publication types

  • Clinical Trial, Phase IV
  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adolescent
  • Adult
  • Anti-Bacterial Agents / pharmacokinetics*
  • Anti-Bacterial Agents / therapeutic use
  • Cystic Fibrosis / blood*
  • Cystic Fibrosis / drug therapy
  • Female
  • Humans
  • Kidney Function Tests
  • Levofloxacin*
  • Male
  • Metabolic Clearance Rate / physiology
  • Ofloxacin / pharmacokinetics*
  • Ofloxacin / therapeutic use
  • Pneumonia, Bacterial / blood*
  • Pneumonia, Bacterial / drug therapy
  • Pseudomonas Infections / blood*
  • Pseudomonas Infections / drug therapy
  • Pseudomonas aeruginosa / drug effects
  • Sputum / microbiology


  • Anti-Bacterial Agents
  • Levofloxacin
  • Ofloxacin