Prescribing-label excerpts
Polymyxin B Sulfate
Reference for: Polymyxin B. Source presentation: injection, powder, for solution. Source route: intramuscular; intrathecal; intravenous; ophthalmic.
The source label presents its clinical-pharmacology findings together. These selected passages retain the source’s study context; the full label provides the complete discussion.
Clinical pharmacology
Polymyxin B sulfate has a bactericidal action against almost all gram-negative bacilli except the Proteus group. Polymyxins increase the permeability of bacterial cell membrane leading to death of the cell. All gram positive bacteria, fungi, and gram-negative cocci are resistant to polymyxin B.
For specific information regarding susceptibility test criteria and associated test methods and quality control standards recognized by FDA for this drug, please see: www.fda.gov/STIC.
Polymyxin B sulfate is not absorbed from the normal alimentary tract. Since the drug loses 50 percent of its activity in the presence of serum, active blood levels are low. Repeated injections may give a cumulative effect. Levels tend to be higher in infants and children. The drug is excreted slowly by the kidneys. Tissue diffusion is poor and the drug does not pass the blood brain barrier into the cerebrospinal fluid. In therapeutic dosage, polymyxin B sulfate causes some nephrotoxicity with tubule damage to a slight degree.
Selected passages from the cited U.S. prescribing label. The studies concern the source product and populations named in each passage; they do not establish Walter-product bioequivalence, an approved indication, or the kinetics of another fixed combination. Tables and the full prescribing information remain available in the source.
Source: DailyMed: Polymyxin B Sulfate — injection, powder, for solution
Reference accessed . Label revision: 2026-06-22.
