Polymyxin B sulfate is a mixture of polymyxins B1 and B2, obtained from Bacillus polymyxa strains. They are basic polypeptides of about eight amino acids and have cationic detergent action on cell membranes. Polymyxin B is used for infections with gram-negative organisms, but may be neurotoxic and nephrotoxic. All gram-positive bacteria, fungi, and the gram-negative cocci, N. gonorrhea and N. menigitidis, are resistant. It is appropriate for treatment of infections of the urinary tract, meninges, and blood stream, caused by susceptible strains of Pseudomonas aeruginosa.
Eye contact; parenteral (intrathecal, intramuscular injection, intravenous drip). Not absorbed from the normal alimentary tract.
Mechanism of Toxicity
Polymyxin B sulfate has a bactericidal action against almost all gram-negative bacilli except the Proteus group. Polymyxin B sulfate interacts with the lipopolysaccharide of the cytoplasmic outer membrane of Gram-negative bacteria, altering membrane permeability and causing cell death. It does not need to enter the cell.
Metabolism
Route of Elimination: The drug is excreted slowly by the kidneys.
No indication of carcinogenicity to humans (not listed by IARC).
Uses/Sources
Used in the treatment of infections of the urinary tract, meninges, and bloodstream caused by susceptible strains of Pseudomonas aeruginosa. It may also be used topically and subconjunctivally in the treatment of infections of the eye caused by susceptible strains of Ps. aeruginosa. (3)
Minimum Risk Level
Not Available
Health Effects
Not Available
Symptoms
Facial flushing, dizziness progressing to ataxia, drowsiness, peripheral paresthesias (circumoral and stocking glove), apnea due to concurrent use of curariform muscle relaxants, other neurotoxic drugs or inadvertent overdosage, and signs of meningeal irritation with intrathecal administration, e.g., fever, headache, stiff neck and increased cell count and protein cerebrospinal fluid. Other reactions occasionally reported: Drug fever, urticarial rash, pain (severe) at intramuscular injection sites, and thrombophlebitis at intravenous injection sites. (3)
