title: An update on the arsenal for multidrug-resistant Acinetobacter infections: polymyxin antibiotics.
abstract: OBJECTIVE
  To review recent clinical pharmacokinetic and pharmacodynamic data to optimize dosing regimens for polymyxin B and colistin for treatment of infections due to A. baumannii.
  
  
  METHODS
  A literature search was performed using the search terms Acinetobacter, polymyxin, colistin, polymyxin B on MEDLINE. Additional references were identified from the resulting citations.
  
  
  RESULTS
  Increasing the dose of polymyxin B or colistin and using either in combination with other antibiotic agents demonstrates improved antimicrobial activity against Acinetobacter spp. Polymyxin B, unlike colistin, is available as an active drug and appears to be relatively unaffected by renal function. This is advantageous both for patients with renal impairment and for those with intact renal function. Achieving therapeutic serum concentrations of colistin may be difficult for those with intact renal function due to rapid clearance of the prodrug, colistimethate sodium (CMS). Clinical data are still lacking for polymyxin B, and it remains to be seen whether advantages demonstrated in PK/PD analyses will persist in the larger scale of patient care and safety.
  
  
  CONCLUSIONS
  The use of higher doses of either colistin or polymyxin B, as well as combination with other antibiotics, may prevent emerging resistance and preserve the activity of polymyxins against A. baumannii.
authors.affiliation: University of California, Los Angeles Health System, Department of Pharmaceutical Services, 1250 16th Street Pharmaceutical Services, Room B470 Santa Monica, CA, 90404 USA. Electronic address: zkassamali@mednet.ucla.edu.
authors.forename: Zahra
authors.initials: Z
authors.lastname: Kassamali
authors.affiliation: University of Washington School of Pharmacy, Department of Pharmacy, 1959 NE Pacific Street, Box 356015, EA-152 Seattle, WA 98195 USA. Electronic address: Rupali@uw.edu.
authors.forename: Rupali
authors.initials: R
authors.lastname: Jain
authors.affiliation: University of Illinois College of Pharmacy, Department of Pharmacy Practice, 833 South Wood Street, RM164, MC886, Chicago, IL 60612. Electronic address: danziger@uic.edu.
authors.forename: Larry H
authors.initials: LH
authors.lastname: Danziger
mesh_terms: D000151:Acinetobacter Infections / Q000188:drug therapy*; D040981:Acinetobacter baumannii; D000900:Anti-Bacterial Agents / Q000008:administration & dosage / Q000493:pharmacokinetics / Q000494:pharmacology / Q000627:therapeutic use*; D003091:Colistin / Q000008:administration & dosage / Q000493:pharmacokinetics / Q000494:pharmacology / Q000627:therapeutic use*; D024901:Drug Resistance, Multiple, Bacterial; D004359:Drug Therapy, Combination; D006801:Humans; D011112:Polymyxin B / Q000008:administration & dosage / Q000493:pharmacokinetics / Q000494:pharmacology / Q000627:therapeutic use*
chemical_list: D000900:Anti-Bacterial Agents; D011112:Polymyxin B; D003091:Colistin
keywords: Acinetobacter infections/drug therapy; Anti-bacterial Agents/administration & dosage; Colistin/administration & dosage; Polymyxins/pharmacology; Polymyxins/therapeutic use