Polymyxin B

Identification

Name
Polymyxin B
Accession Number
DB00781 / J2VZ07J96K
Groups
10 Person ANSI
Description

Polymyxin B became determined inside the 1940s[A176429]. they're primary polypeptides of about eight amino acids and feature cationic detergent action on cellular membranes[A176426]. Polymyxin B is used for infections with gram-poor organisms, but can be neurotoxic and nephrotoxic[A176426,FDA Label]. All gram-fine bacteria, fungi, and the gram-negative cocci, are resistant[A176426]. it's far suitable for remedy of infections of the urinary tract, meninges, and blood circulate, due to prone lines of _Pseudomonas aeruginosa_[FDA Label]. Polymyxin B has a slim healing index and so its use is limited and unlikely to be used first line[A176429].

Pharmacology

Pharmacodynamics

Polymyxin B is an antibiotic that disrupts the outer cell membrane of Gram negative bacteria, binds and neutralizes lipopolysaccharide, and inhibits respiration of Gram-negative bacterial cells[A176426]. Polymyxin B can be given by a number of routes to treat susceptible Gram negative bacterial infections[A176426]. Absorption of the drug is poor (though not necessary for most of its activity) and the excreted drug is unchanged by metabolic processes[A176432,A176390]. Polymyxin B is generally indicated for susceptible Gram negative infections of the urinary tract, meninges, and blood stream[FDA Label].

Indication

Polymyxin B is indicated for the treatment of infections of the urinary tract, meninges, and blood stream, caused by susceptible strains of <i>Pseudomonas aeruginosa</i>[FDA Label].

Action

The alpha and gamma diaminobutyric acid of a positively charged polymyxin B forms an electrostatic interaction with the phosphate groups of a negatively charged lipid A on the outer membrane of a Gram negative bacterium[A176426]. Calcium and Magnesium ions are displaced from phosphates of the membrane lipids, destabalising the lipopolysaccharide (LPS), increasing membrane permeability, causing cytoplasmic leaking, and killing the cell[A176426]. Polymyxin B can also bind and neutralize LPS released during bacterial lysis, preventing reactions to endotoxin[A176426]. A third activity of polymyxin B is the inhibition of type II NADH-quinone oxidoreductases in the bacterial inner membrane, which are essential for respiration[A176426]. Polymyxin is active against common Gram negative bacteria but not Gram negative cocci, Gram positive bacteria, or anaerobic bacteria[A176426].