← Search & browse all drugs

polymyxin B

S01AA18

Forms & Strengths

Injectable: 500,000 units per vial (sterile lyophilized powder)
Ophthalmic solution: 10,000 units/mL combined with gramicidin/neomycin
Topical ointment: 10,000 units/g combined with bacitracin and/or neomycin

Adult Dosing

Systemic (IV/IM): 15,000 to 25,000 units/kg/day divided every 12 hours in patients with normal renal function
Intrathecal: 50,000 units once daily for 3-4 days, then 50,000 units every other day for meningitis
Ophthalmic: 1 to 2 drops into affected eye(s) every 1 to 4 hours depending on severity

Pediatric Dosing

Systemic (IV/IM): 15,000 to 25,000 units/kg/day divided every 12 hours (use lower end in neonates)
Intrathecal (children >2 years): 50,000 units once daily for 3-4 days, then every other day
Ophthalmic: 1 to 2 drops into affected eye(s) every 1 to 4 hours

Indications

Treatment of severe infections caused by susceptible strains of Pseudomonas aeruginosa
Meningitis caused by susceptible gram-negative pathogens via intrathecal administration
Topical treatment of superficial ocular infections involving the cornea and conjunctiva

Mechanism of Action

Binds to phospholipids in the bacterial cytoplasmic membrane of susceptible gram-negative bacteria
Alters membrane permeability, leading to leakage of intracellular components and cell death
Binds and neutralizes bacterial lipopolysaccharides (endotoxins)

Contraindications

Hypersensitivity to polymyxins or any component of the formulation
Concurrent use of nephrotoxic or neurotoxic drugs when administered systemically
Routine use in premature or newborn infants due to immature renal function

Adverse Reactions

Nephrotoxicity (albuminuria, cellular casts, azotemia, acute tubular necrosis)
Neurotoxicity (facial flushing, dizziness, ataxia, drowsiness, neuromuscular blockade, apnea)
Local irritation, pain at injection sites, and thrombophlebitis

Drug Interactions

Concurrent use with aminoglycosides increases the risk of nephrotoxicity and ototoxicity
Neuromuscular blocking agents (e.g., tubocurarine) may potentiate respiratory depression and apnea
Potentiation of neuromuscular blockade with inhalation anesthetics and opioid analgesics

Curated Content: Needs Vetting Before Put to Clinical Use