Approved & therapeutic
Polymyxin B
Poly-Rx
Polymyxin B is a polypeptide antibiotic closely related to colistin, used systemically against multidrug-resistant Gram-negative infection and topically in combination ointments and eye preparations.
Also known as: polymyxin B sulfate
- Status
- Polymyxin B is approved by the U.S. FDA and has official prescribing information.
- Evidence
- Approved labeling. Official prescribing information exists, based on clinical trials in people.
- Half-life
- Approximately 9 to 12 hours after intravenous administration.
- How it's taken
- Intravenous infusion; also topical and ophthalmic preparations
- Mechanism
- Immune modulation
How Polymyxin B works
Polymyxin B binds lipid A in the Gram-negative outer membrane, displacing stabilising divalent cations and disrupting membrane integrity. It also binds and neutralises circulating endotoxin, a property exploited in extracorporeal haemoperfusion devices.
What research has looked at
- Active against carbapenem-resistant Gram-negative organisms including Acinetobacter and Klebsiella.
- Unlike colistimethate it is administered as the active drug rather than a prodrug, so it reaches effective concentrations faster and more predictably.
- It is cleared largely by non-renal routes, so dosing is less dependent on renal function than colistin.
- Widely used topically in combination products, where systemic absorption is negligible.
Evidence level: Approved labeling. Official prescribing information exists, based on clinical trials in people. These are areas studied or reported, not promised effects.
Reported side effects and risks
- Nephrotoxicity, comparable to colistin and dose-limiting.
- Neurotoxicity including paraesthesias, ataxia and neuromuscular blockade.
- Hyperpigmentation of the skin has been reported with systemic use.
- It penetrates the central nervous system poorly, and intrathecal administration has been used for meningitis with its own risks.
- Topical preparations can cause contact sensitisation.
Sources
- FDA approved-drug listing for polymyxin B · U.S. Food & Drug Administration
- DailyMed prescribing information for polymyxin B · NIH · DailyMed
- PubMed research on polymyxin B multidrug resistant gram negative · NIH · National Library of Medicine
- DrugBank record for polymyxin B · DrugBank
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Polymyxin B FAQ
What is Polymyxin B?
Polymyxin B is a polypeptide antibiotic closely related to colistin, used systemically against multidrug-resistant Gram-negative infection and topically in combination ointments and eye preparations.
How does Polymyxin B work?
Polymyxin B binds lipid A in the Gram-negative outer membrane, displacing stabilising divalent cations and disrupting membrane integrity. It also binds and neutralises circulating endotoxin, a property exploited in extracorporeal haemoperfusion devices.
Is Polymyxin B FDA approved?
Yes. Polymyxin B is approved by the U.S. FDA and has official prescribing information. Evidence level: approved labeling. Official prescribing information exists, based on clinical trials in people.
What is the half-life of Polymyxin B?
Reported half-life: Approximately 9 to 12 hours after intravenous administration.
How is Polymyxin B taken?
Intravenous infusion; also topical and ophthalmic preparations.
What side effects have been reported with Polymyxin B?
Reported in the sources: Nephrotoxicity, comparable to colistin and dose-limiting; Neurotoxicity including paraesthesias, ataxia and neuromuscular blockade; Hyperpigmentation of the skin has been reported with systemic use; It penetrates the central nervous system poorly, and intrathecal administration has been used for meningitis with its own risks; Topical preparations can cause contact sensitisation.
Educational summary compiled from the sources listed above. Not medical advice. Peptide Vault does not sell, source or recommend any compound. Talk to a qualified clinician before starting or changing anything.