title: Predicting the clinical efficacy of antibiotics: toward definitive criteria.
abstract: BACKGROUND
  Both the in vitro microbiologic activity of an antibiotic drug and its pharmacokinetic characteristics are important criteria to be considered when predicting clinical efficacy. At present, however, it is not clear which pharmacokinetic parameters are the most useful in determining optimal therapeutic approaches.
  
  
  OBJECTIVE
  To review the various pharmacokinetic properties of antibiotics, with special reference to the cephalosporins, and to consider the contributions that these make to the definitive prediction of clinical efficacy.
  
  
  CONCLUSIONS
  It is important, when attempting to use the pharmacokinetic parameters in conjunction with the minimum inhibitory concentrations for possible pathogens to predict clinical efficacy, to measure the concentration of an antibacterial drug at the site of bacterial proliferation. In most cases bacteria proliferate in the interstitial fluid; therefore it is important to choose an antibiotic that achieves high concentrations in this compartment; the intracellular concentration is less critical. The interstitial fluid concentration is in equilibrium with the free (i.e. non-protein-bound) serum concentration and either of these antibiotic levels is more predictive of clinical efficacy than are intracellular levels.
authors.affiliation: Department of Pharmacology, University of Milan, Italy.
authors.forename: F
authors.initials: F
authors.lastname: Scaglione
mesh_terms: D000900:Anti-Bacterial Agents / Q000493:pharmacokinetics* / Q000627:therapeutic use*; D001424:Bacterial Infections / Q000188:drug therapy*; D002511:Cephalosporins / Q000493:pharmacokinetics* / Q000627:therapeutic use*; D004432:Ear, Middle / Q000378:metabolism; D006801:Humans; D018942:Macrolides; D008826:Microbial Sensitivity Tests
chemical_list: D000900:Anti-Bacterial Agents; D002511:Cephalosporins; D018942:Macrolides