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Updated: Jun 29, 2026

Multiplex Therapeutic Drug Monitoring by Isotope-dilution HPLC-MS/MS of Antibiotics in Critical Illnesses
11:17

Multiplex Therapeutic Drug Monitoring by Isotope-dilution HPLC-MS/MS of Antibiotics in Critical Illnesses

Published on: August 30, 2018

Pharmacokinetics of intravenous polymyxin B in critically ill patients

Alexandre P Zavascki1, Luciano Z Goldani, Guoying Cao

  • 1Division of Infectious Diseases, Hospital de Clínicas de Porto Alegre, Porto Alegre, Brazil.

Clinical Infectious Diseases : an Official Publication of the Infectious Diseases Society of America
|October 9, 2008
PubMed
Abstract

Insights

Polymyxin B, used for resistant infections, showed higher plasma protein binding in critically ill patients. Elimination is mainly nonrenal, suggesting current doses may need reassessment for severe infections.

Area of Science:

  • Pharmacology
  • Critical Care Medicine
  • Infectious Diseases

Background:

  • Polymyxin B is increasingly vital for treating multidrug-resistant Gram-negative bacterial infections.
  • Limited pharmacokinetic data exists for polymyxin B, especially in intensive care settings.

Purpose of the Study:

  • To investigate the pharmacokinetics of polymyxin B in critically ill patients.
  • To determine plasma concentrations, protein binding, and urinary recovery of polymyxin B.

Main Methods:

  • Intravenous administration of polymyxin B to 8 critically ill patients.
  • Collection of plasma and urine samples for polymyxin B concentration analysis.
  • Determination of plasma protein binding using high-performance liquid chromatography.

Main Results:

  • Polymyxin B was well tolerated with peak plasma concentrations ranging from 2.38 to 13.9 mg/L.
  • Urinary recovery of unchanged polymyxin B was low (0.04%-0.86%).
  • Plasma protein binding was significantly higher in patients (78.5%-92.4%) compared to healthy subjects (55.9%).

Conclusions:

  • This study provides initial data on polymyxin B pharmacokinetics in critically ill patients.
  • Polymyxin B is primarily eliminated via nonrenal routes, with clearance independent of renal function.
  • Further research is needed to validate current polymyxin B dosing for severe infections in critically ill populations.

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