Side-by-Side Comparison · 2026

Bacitracin vs Polymyxin B

Bacitracin vs Polymyxin B — mechanism, half-life, dosing, and research status compared. Which is right for your protocol?

Bacitracin
Antimicrobial Peptide

Bacitracin is a polycyclic peptide antibiotic from Bacillus subtilis licheniformis, first isolated in 1945 from wound cultures of a 7-year-old girl named Margaret Tracy (hence "bacitracin"). It is available OTC in Neosporin and similar triple-antibiotic ointments and is one of th...

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Polymyxin B
Antimicrobial Peptide

Polymyxin B is a cyclic lipopeptide antibiotic from Bacillus polymyxa that was approved in the 1960s and fell out of favor due to nephrotoxicity, but has experienced a major clinical resurgence as a last-resort treatment for carbapenem-resistant Gram-negative infections (Acinetob...

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Key Parameters
Parameter Bacitracin Polymyxin B
Category Antimicrobial Peptide Antimicrobial Peptide
Research FDA Approved (topical) FDA Approved
Half-Life Hours (topical) 6-8 hours
Typical Dose 400-500 units/g ointment 15,000-25,000 units/kg/day IV
Frequency 1-3x daily Every 12 hours IV
Route Topical IV / IM / Topical / Intrathecal
FDA Status Approved (topical) Approved (systemic Gram-negative infections)

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Frequently Asked Questions
What is the difference between Bacitracin and Polymyxin B?
Bacitracin: Bacitracin is a polycyclic peptide antibiotic from Bacillus subtilis licheniformis, first isolated in 1945 from wound cultures of a 7-year-old girl named Margaret Tracy (hence "bacitracin"). It is ava... Polymyxin B: Polymyxin B is a cyclic lipopeptide antibiotic from Bacillus polymyxa that was approved in the 1960s and fell out of favor due to nephrotoxicity, but has experienced a major clinical resurgence as a l...
Which has a longer half-life, Bacitracin or Polymyxin B?
Bacitracin half-life: Hours (topical). Polymyxin B half-life: 6-8 hours.
Can you stack Bacitracin and Polymyxin B?
Bacitracin and Polymyxin B are in the same category and used together in research protocols. Always consult relevant literature and follow appropriate guidelines.

For research use only. Not medical advice. ASCEND does not conduct or endorse any specific research protocol. Always consult relevant scientific literature and regulatory guidelines.