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Polymyxin B

Peptide

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.

Quick Answer

What it is

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.

Key findings

  • Grade A: Carbapenem-Resistant GNB Infections (Multidrug-Resistant Bacterial Infections)
  • Grade A: MDR Pseudomonas aeruginosa (Multidrug-Resistant Bacterial Infections)
  • Grade A: MDR Acinetobacter baumannii (Multidrug-Resistant Bacterial Infections)

Safety

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

This peptide information is for educational and research purposes only. Peptides may not be FDA-approved for human use and may only be legally available for research purposes. Consult qualified healthcare professionals before considering any peptide compounds.

ℹ️ Quick Facts: Polymyxin B

Quick Facts: Polymyxin B

  • Best Evidence:Grade A
  • Conditions Studied:1
  • Research Outcomes:10
  • Grade A Findings:4
  • Grade B Findings:3
  • Key Effect:Multidrug-Resistant Bacterial Infections
A4
B3
C2
D1
1 conditions · 10 outcomes

Detailed Outcomes

A
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.
moderate↑Improves
A
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.
moderate↑Improves
A
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.
moderate↑Improves
A
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.
moderate↑Worsens
B
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.
moderate↑Improves
B
Safety/Tolerability
11 human trials support this finding. Human clinical trial data available.
moderate↑Improves
B
Kidney Function
10 human trials support this finding. Human clinical trial data available.
moderate↑Improves
C
Antimicrobial Activity
5 preclinical studies support this finding. Primarily preclinical evidence.
small↑Improves
C
Sepsis Outcomes
4 human trials support this finding. Human clinical trial data available.
small↓Improves
D
Anti-Inflammatory Activity
2 preclinical studies support this finding. Primarily preclinical evidence.
small↑Improves

Research Citations (33)

Polymyxin B delivery systems: smart solutions for improved antibacterial activity and reduced toxicity.
(2025)
PMID: 40617810
Polymyxin B and silver nanoparticles: a nanotechnology-driven approach to overcome antibiotic resistance.
(2025)
PMID: 40757877
Relationship between plasma polymyxin B concentrations and acute kidney injury in critically ill elderly patients: Findings from a prospective study.
(2025)
PMID: 39956623
Clinical outcomes and pharmacokinetics/pharmacodynamics of intravenous polymyxin B treatment for various site carbapenem-resistant gram-negative bacterial infections: a prospective observational multicenter study
(2024)
PMID: 40047414
Polymyxin B Hemoperfusion in Septic Shock: Finding the Right Patients by Analyzing Real-World Big Data.
(2023)
PMID: 35654006
Polymyxin B-related neurotoxicity: a brief case report.
(2023)
PMID: 37286311
Effectiveness, nephrotoxicity, and therapeutic drug monitoring of polymyxin B in nosocomial pneumonia among critically ill patients
(2022)
PMID: 35586931
Population pharmacokinetics and clinical outcomes of polymyxin B in paediatric patients with multidrug-resistant Gram-negative bacterial infections
(2022)
PMID: 35924405
Trough polymyxin B plasma concentration is an independent risk factor for its nephrotoxicity.
(2022)
PMID: 34449094
Population pharmacokinetics of polymyxin B and dosage strategy in critically ill patients with/without continuous renal replacement therapy.
(2022)
PMID: 35609779

Related Peptides

Colistin (Polymyxin E)

Peptide

1 shared condition · 9 outcomes

Colistin is a cyclic lipopeptide antibiotic (polymyxin E) discovered 1947, FDA-approved 1959. Administered as inactive prodrug colistimethate sodium (CMS) for parenteral use. WHO Essential Medicine and critically important for human medicine. Last-resort therapy for MDR gram-negative infections. Meta-analysis of 5 RCTs (n=377): 36% nephrotoxicity incidence vs 15% comparators (NNH=5). Pediatric review (17 studies, n=312): Effective for BSI, pneumonia, meningitis in neonates. SAFETY CONCERN: Dose-dependent nephrotoxicity (40-45% incidence); neurotoxicity reported; 75% AKI recovery upon discontinuation.