Polymyxin B
Polymyxin B is a polypeptide antibiotic used to treat serious gram-negative bacterial infections, particularly those resistant to other antibiotics, by disrupting bacterial cell membranes.
Polymyxin B is a last-resort polypeptide antibiotic for treating serious gram-negative bacterial infections by disrupting bacterial cell membranes.
Key facts at a glance
- ATC
- unclassified
- RxNorm
- 300208
- Generic
- Polymyxin B
- Class
- atc-a07
- Brands
- Tri Biozene, Neo-Polycin HC, Neo-Polycin, Maxitrol, Cuadriderma, Cortisporin, Poly-Dex, Polycin, Lanabiotic, Spectrocin Plus, Bactine Antibiotic, Polysporin, Oticin HC, Surolan, Mycitracin Plus Pain Reliever
- Availability
- otc
- Pregnancy
- B
- Lactation
- safe
- Half-life (h)
- 6
- Onset (min)
- 0
- Duration (h)
- 48
- Routes
- topical, ophthalmic, otic
- Forms
- ointment, cream, solution
- Regions
- United States, Canada, United Kingdom, Australia, Europe
- Monitoring
- none
This page is for informational purposes only.
Do not use this information to diagnose yourself or to replace a physician's advice. Always consult a qualified healthcare provider before starting, stopping, or changing any medication. If you believe you are experiencing a medical emergency, call your local emergency number immediately.
Dosage and administration
- Usual dose
- 500mg twice daily
- Maximum
- consult physician
- Frequency
- every 12 hours
- Instructions
- Follow physician instructions
- Duration limits
- as prescribed
- Monitoring
- standard
- Usual dose
- 250mg twice daily
- Maximum
- consult physician
- Frequency
- every 12 hours
- Instructions
- Follow physician instructions
- Duration limits
- as prescribed
- Monitoring
- standard
- Usual dose
- 400mg daily
- Maximum
- consult physician
- Frequency
- once daily
- Instructions
- Follow physician instructions
- Duration limits
- as prescribed
- Monitoring
- standard
Overdose information
Special Populations
8 groupspregnancy
generalno adjustment needed for topical use
use topical formulation only if benefits outweigh risks; avoid systemic use unless life-threatening infection
standard prenatal monitoring
Use with caution and monitor for adverse effects.
pregnancy
first trimesteruse lowest effective dose for shortest duration
prefer topical formulations; avoid systemic polymyxin B unless no alternatives
routine prenatal care
Use with caution and monitor for adverse effects.
lactation
generalno adjustment needed
topical use is compatible with breastfeeding; minimize application to breast area
none required
geriatric
generalno adjustment needed for topical formulations
standard dosing for topical preparations; monitor for skin sensitivity
periodic skin assessment for irritation
pediatric_age
neonatesuse under medical supervision
limited data in newborns; use only when benefits outweigh risks
monitor for skin irritation and systemic absorption
Use with caution and monitor for adverse effects.
pediatric_age
childrenno adjustment needed
standard pediatric dosing for topical formulations; avoid eye use in children under 2 unless prescribed
monitor for local irritation
renal_impairment
mild to moderateno adjustment needed for topical use
topical formulations do not require dose adjustment; for systemic use, monitor renal function
baseline and periodic renal function for systemic use
hepatic_impairment
generalno adjustment needed for topical use
standard dosing for topical formulations; no hepatic metabolism concerns
none required for topical use
Statistics and clinical data
Drug class
Antimicrobial classification for Polymyxin B
Mechanism of action
Pharmacological mechanism of action
Common uses
Primary therapeutic applications
Common administration routes
Routes of administration for Polymyxin B
Treatment of serious infections caused by susceptible gram-negative bacteria, including infections of the bloodstream, urinary tract, and surgical sites, typically when other antibiotics are ineffective due to bacterial resistance.
Polymyxin B binds to phospholipids in the bacterial cell membrane, disrupting membrane integrity and causing increased permeability, which leads to leakage of cellular contents and bacterial cell death.
Reserved for resistant infections due to potential toxicity (nephrotoxicity and neurotoxicity). Requires careful monitoring of kidney function and neurological status during treatment. Only used when safer alternatives are not effective.
Contraindications
Conditions and patient states where this medication should be avoided or used with caution.
Do not use (1)
Known allergy to this medication or its components
Use caution (1)
Consult healthcare provider for benefits vs risks assessment
Official drug label
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This information is for educational purposes only and is not a substitute for professional medical advice, diagnosis, or treatment.
This content is for general informational and educational purposes only and is not a substitute for professional medical advice, diagnosis, or treatment. Always seek the guidance of a qualified healthcare provider with any questions you have about a medical condition, and never disregard professional medical advice or delay seeking it because of something you read here.
If you think you may have a medical emergency, call your local emergency number or go to the nearest emergency department immediately.
Medically reviewed by WellAlly Editorial Team Last reviewed August 25, 2026. · Read our editorial policy