Polymyxin_b
Polymyxin B
Antibiotic medication
Polymyxin B, sold under the brand name Poly-Rx among others, is an antibiotic used to treat meningitis, pneumonia, sepsis, and urinary tract infections.[1] While it is useful for many Gram negative infections, it is not useful for Gram positive infections.[1] It can be given by injection into a vein, muscle, or cerebrospinal fluid or inhaled.[1] The injectable form is generally only used if other options are not available.[2] It is also available as the combinations bacitracin/polymyxin B and neomycin/polymyxin B/bacitracin for use on the skin.[3][4]
Common side effects when given by injection include kidney problems, neurological problems, fever, itchiness, and rash.[1] Injections into muscle may result in significant pain.[1] Other serious side effects may include fungal infections, anaphylaxis, and muscle weakness.[1] It is unclear if use during pregnancy is safe for the baby.[1] Polymyxin B works by breaking down the cytoplasmic membrane which generally results in bacterial cell death.[1]
Polymyxin B was approved for medical use in the United States in 1964.[1] It is on the World Health Organization's List of Essential Medicines.[5] It is available as a generic medication.[1] In Europe it is only approved to be applied to the skin as of 2015.[6] It is derived from the bacterium Paenibacillus polymyxa (formerly known as Bacillus polymyxa).[2]