All available reports of in vitro antibacterial activity, animal and clinical trials, and case reports were reviewed. The polymyxins are amphipathic molecules that interact with lipopolysaccharide in the bacterial outer membrane. They have potent antiendotoxic properties and antibacterial activity against Pseudomonas aeruginosa and many of the Enterobacteriaceae. Dosing must be altered in renal failure since the kidney is the primary route of elimination. Distribution into pleural fluid, joints, and cerebrospinal fluid is poor.
Toxic effects involve the kidney and central nervous system.
The polymyxins are recommended for serious systemic infections caused by gram-negative bacteria that are resistant to other agents.