Rational Combinations of Polymyxins with Other Antibiotics

Phillip J. Bergen, Nicholas M. Smith, Tyler B. Bedard, Zackery P. Bulman, Raymond Cha, Brian T. Tsuji

Research output: Chapter in Book/Report/Conference proceedingChapter (Book)Otherpeer-review

10 Citations (Scopus)


Combinations of antimicrobial agents are often used in the management of infectious diseases. Antimicrobial agents used as part of combination therapy are often selected empirically. As regrowth and the emergence of polymyxin (either colistin or polymyxin B) resistance has been observed with polymyxin monotherapy, polymyxin combination therapy has been suggested as a possible means by which to increase antimicrobial activity and reduce the development of resistance. This chapter provides an overview of preclinical and clinical investigations of CMS/colistin and polymyxin B combination therapy. In vitro data and animal model data suggests a potential clinical benefit with many drug combinations containing clinically achievable concentrations of polymyxins, even when resistance to one or more of the drugs in combination is present and including antibiotics normally inactive against Gram-negative organisms. The growing body of data on the emergence of polymyxin resistance with monotherapy lends theoretical support to a benefit with combination therapy. Benefits include enhanced bacterial killing and a suppression of polymyxin resistant subpopulations. However, the complexity of the critically ill patient population, and high rates of treatment failure and death irrespective of infection-related outcome make demonstrating a potential benefit for polymyxin combinations extremely challenging. Polymyxin combination therapy in the clinic remains a heavily debated and controversial topic. When combinations are selected, optimizing the dosage regimens for the polymyxin and the combinatorial agent is critical to ensure that the benefits outweigh the risk of the development of toxicity. Importantly, patient characteristics, pharmacokinetics, the site of infection, pathogen and resistance mechanism must be taken into account to define optimal and rational polymyxin combination regimens in the clinic.

Original languageEnglish
Title of host publicationPolymyxin Antibiotics
Subtitle of host publicationFrom Laboratory Bench to Bedside
EditorsJian Li, Roger L. Nation, Keith S. Kaye
Place of PublicationSwitzerland
Number of pages38
ISBN (Electronic)9783030163730
ISBN (Print)9783030163716
Publication statusPublished - 2019

Publication series

NameAdvances in Experimental Medicine and Biology
ISSN (Print)0065-2598
ISSN (Electronic)2214-8019


  • Antibiotic combination therapy
  • Pharmacodynamics
  • Pharmacokinetics
  • Polymyxin
  • Synergy

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