Skip to content
Dr. Grey AI

Peptide

Polymyxin B

Polymyxin B is a cyclic lipopeptide antibiotic discovered in the 1940s from Paenibacillus polymyxa. Re-established as last-resort therapy for MDR/XDR gram-negative infections including carbapenem-resistant Enterobacteriaceae (CRE), MDR Pseudomonas aeruginosa, and MDR Acinetobacter baumannii. Multicenter studies (n=312): 70.5% 14-day survival for CRGNB infections. Less nephrotoxic than colistin. Non-renal elimination allows use without dose adjustment for renal impairment. SAFETY CONCERN: Dose-limiting nephrotoxicity (35-60% AKI incidence); narrow therapeutic window.

Research notice. This page is for education and research. Peptides may not be FDA-approved for human use and may only be legally available for research. Talk to a qualified clinician before considering any peptide.

Best evidence
Grade A
Conditions studied
1
Outcomes
10
Graded outcomes
4321

Evidence by condition

  • Strong
  • Moderate
  • Limited
  • Very limited

1 condition, plus general outcomes

Multidrug-Resistant Bacterial Infections

Multidrug-Resistant Bacterial Infections: outcomes studied for Polymyxin B
GradeOutcomeEffectSizeStudiesPeopleStudies list
Carbapenem-Resistant GNB Infections

Prospective multicenter study (n=312): 14-day survival 70.5% for CRGNB infections. Site-specific outcomes: LRTI 67.7%, IAI 80.3%, BSI 69.7% survival. Last-resort efficacy against otherwise untreatable MDR pathogens.

Improves (the measure goes up)Moderate effect12 studies

Studies that measured carbapenem-resistant gnb infections

and 2 more in the citations list

Nephrotoxicity Risk

SAFETY CONCERN: AKI incidence 35-60% across studies. Risk factors: duration of use, BMI, advanced age, concomitant nephrotoxins. Generally reversible upon discontinuation. Possibly milder than colistin-associated nephrotoxicity.

Worsens (the measure goes up)Moderate effect9 studies

Studies that measured nephrotoxicity risk

MDR Pseudomonas aeruginosa

Rapid bactericidal activity against MDR P. aeruginosa with low acquired resistance rates. MIC90 generally 1-2 mg/L. Essential option when all other antipseudomonal agents have failed.

Improves (the measure goes up)Moderate effect7 studies

Studies that measured mdr pseudomonas aeruginosa

MDR Acinetobacter baumannii

Retained activity against extensively drug-resistant A. baumannii. Organism cleared in 88% of patients in clinical studies. Critical therapy for nosocomial Acinetobacter infections.

Improves (the measure goes up)Moderate effect7 studies

Studies that measured mdr acinetobacter baumannii

Pediatric Efficacy

Population PK study (n=19 pediatric patients): Clinical success 73.7% with only 5.3% AKI rate. Weight-based dosing (1.33-2.53 mg/kg/day). Lower nephrotoxicity risk in pediatric population.

Improves (the measure goes up)Moderate effect7 studies

Studies that measured pediatric efficacy

General

General: outcomes studied for Polymyxin B
GradeOutcomeEffectSizeStudiesPeopleStudies list
Kidney Function

10 human trials support this finding. Human clinical trial data available.

Improves (the measure goes up)Moderate effect10 studies

Studies that measured kidney function

Safety/Tolerability

11 human trials support this finding. Human clinical trial data available.

Improves (the measure goes up)Moderate effect10 studies

Studies that measured safety/tolerability

Antimicrobial Activity

5 preclinical studies support this finding. Primarily preclinical evidence.

Improves (the measure goes up)Small effect4 studies

Studies that measured antimicrobial activity

Sepsis Outcomes

4 human trials support this finding. Human clinical trial data available.

Improves (the measure goes down)Small effect4 studies

Studies that measured sepsis outcomes

Anti-Inflammatory Activity

2 preclinical studies support this finding. Primarily preclinical evidence.

Improves (the measure goes up)Small effect2 studies

Studies that measured anti-inflammatory activity

Key findings

  • Carbapenem-Resistant GNB InfectionsMultidrug-Resistant Bacterial InfectionsImproves (the measure goes up)
  • Nephrotoxicity RiskMultidrug-Resistant Bacterial InfectionsWorsens (the measure goes up)
  • MDR Pseudomonas aeruginosaMultidrug-Resistant Bacterial InfectionsImproves (the measure goes up)

Safety notes in the studies

  • Risk factors: duration of use, BMI, advanced age, concomitant nephrotoxins.
  • Lower nephrotoxicity risk in pediatric population.

Studies cited

33 studies from PubMed

  1. Polymyxin B delivery systems: smart solutions for improved antibacterial activity and reduced toxicity.Journal of drug targeting, 2025 · PMID 40617810
  2. Polymyxin B and silver nanoparticles: a nanotechnology-driven approach to overcome antibiotic resistance.Drug development and industrial pharmacy, 2025 · PMID 40757877
  3. Relationship between plasma polymyxin B concentrations and acute kidney injury in critically ill elderly patients: Findings from a prospective study.The Journal of international medical research, 2025 · PMID 39956623
  4. Clinical outcomes and pharmacokinetics/pharmacodynamics of intravenous polymyxin B treatment for various site carbapenem-resistant gram-negative bacterial infections: a prospective observational multicenter studyAntimicrob Agents Chemother, 2024 · PMID 40047414
  5. Polymyxin B Hemoperfusion in Septic Shock: Finding the Right Patients by Analyzing Real-World Big Data.Blood purification, 2023 · PMID 35654006
  6. Polymyxin B-related neurotoxicity: a brief case report.European journal of hospital pharmacy : science and practice, 2023 · PMID 37286311
  7. Effectiveness, nephrotoxicity, and therapeutic drug monitoring of polymyxin B in nosocomial pneumonia among critically ill patientsAnn Pharmacother, 2022 · PMID 35586931
  8. Population pharmacokinetics and clinical outcomes of polymyxin B in paediatric patients with multidrug-resistant Gram-negative bacterial infectionsJ Antimicrob Chemother, 2022 · PMID 35924405
  9. Trough polymyxin B plasma concentration is an independent risk factor for its nephrotoxicity.British journal of clinical pharmacology, 2022 · PMID 34449094
  10. Population pharmacokinetics of polymyxin B and dosage strategy in critically ill patients with/without continuous renal replacement therapy.European journal of pharmaceutical sciences : official journal of the European Federation for Pharmaceutical Sciences, 2022 · PMID 35609779
  11. Efficacy and safety of intraventricular polymyxin B plus continuous ventricular drainage for the treatment of intracranial infection caused by drug-resistant Acinetobacter baumannii.Annals of palliative medicine, 2022 · PMID 35249326
  12. Clinical outcomes and safety of polymyxin B in the treatment of carbapenem-resistant Gram-negative bacterial infections: a real-world multicenter studyFront Pharmacol, 2021 · PMID 34656132
  13. Polymyxin B-modified conjugated oligomer nanoparticle for targeted identification and enhanced photodynamic antimicrobial therapy.Chemical communications (Cambridge, England), 2021 · PMID 34633009
  14. Does renal function matter for polymyxin B?British journal of clinical pharmacology, 2021 · PMID 33325056
  15. Risk factors for nephrotoxicity associated with polymyxin B therapy in Chinese patients.International journal of clinical pharmacy, 2021 · PMID 33439427
  16. Effect of Different Dosage Frequency of Polymyxin B on Rat Nephrotoxicity.Drug design, development and therapy, 2021 · PMID 33623370
  17. Nanocapsule system tackles polymyxin B toxicity.Nature reviews. Nephrology, 2021 · PMID 34545227
  18. Efficacy and safety of polymyxin B in carbapenem-resistant gram-negative organisms infections.BMC infectious diseases, 2021 · PMID 34607561
  19. Lysophosphatidylcholine Potentiates Antibacterial Activity of Polymyxin B.Antimicrobial agents and chemotherapy, 2020 · PMID 32988824
  20. Polymyxin B clinical outcomes: A prospective study of patients undergoing intravenous treatmentJ Glob Antimicrob Resist, 2019 · PMID 30666679
  21. Treatment with a polymyxin B filter to capture endotoxin in sepsis patients: is there a signal for therapeutic efficacy?Intensive care medicine, 2019 · PMID 30511248
  22. Population Pharmacokinetics of Polymyxin BClin Microbiol Infect, 2018 · PMID 29238962
  23. Modulation by Polymyxin-B Hemoperfusion of Inflammatory Response Related to Severe Peritonitis.Shock (Augusta, Ga.), 2017 · PMID 27984535
  24. Nephrotoxicity of Polymyxins: Is There Any Difference between Colistimethate and Polymyxin B?Antimicrobial agents and chemotherapy, 2017 · PMID 27993859
  25. Role of Renal Drug Exposure in Polymyxin B-Induced Nephrotoxicity.Antimicrobial agents and chemotherapy, 2017 · PMID 28096166
  26. Polymyxin B Nephrotoxicity: From Organ to Cell Damage.PloS one, 2016 · PMID 27532263
  27. Polymyxin B hemoperfusion in sepsis: growing body of evidence and occasional conflicting results.Blood purification, 2015 · PMID 25998615
  28. Uptake of polymyxin B into renal cells.Antimicrobial agents and chemotherapy, 2014 · PMID 24733472
  29. Population pharmacokinetics of intravenous polymyxin B in critically ill patients: implications for selection of dosage regimensClin Infect Dis, 2013 · PMID 23697744
  30. Polymyxin B-immobilized fiber column hemoperfusion therapy for septic shock.Shock (Augusta, Ga.), 2011 · PMID 21654557
  31. Polymyxin B for the treatment of multidrug-resistant pathogens: a critical reviewClin Infect Dis, 2007 · PMID 17878146
  32. Polymyxin B nephrotoxicity and efficacy against nosocomial infections caused by multiresistant gram-negative bacteriaAntimicrob Agents Chemother, 2003 · PMID 12878536
  33. Inhibition of lipopolysaccharide-induced TNF-alpha production by semisynthetic polymyxin-B conjugated dextran.Biotechnology therapeutics, 1994-1995 · PMID 8608324