KEY POINTS
- Polymyxin B works as a cationic detergent, damaging bacterial cytoplasmic membrane and causing leakage of intracellular contents
- Polymyxin E (colistin, colistmethate sodium) is very similar to polymyxin B in spectrum and toxicity
- See below resource “chalk and cheese” for a great comparison of the two
- Polymyxin E (colistin, colistmethate sodium) is very similar to polymyxin B in spectrum and toxicity
- Available as injectable and is used topical intra-operative as well
- Only used for Gram negative bacteria, like Pseudomonas aeruginosa and Acinetobacter baumannii
- A last-line antibiotic and is typically only used when few to no other options exist
- Strongly consider combination therapy when using this antibiotic
- Highly associated with nephrotoxicity
RESOURCES
- Polymyxin B Package Insert
- International Consensus Guidelines for the Optimal Use of the Polymyxins: Endorsed by the American College of Clinical Pharmacy (ACCP), European Society of Clinical Microbiology and Infectious Diseases (ESCMID), Infectious Diseases Society of America (IDSA), International Society for Anti‐infective Pharmacology (ISAP), Society of Critical Care Medicine (SCCM), and Society of Infectious Diseases Pharmacists (SIDP). Pharmacotherapy. 2019.
- Polymyxins: antibacterial activity, susceptibility testing, and resistance mechanisms encoded by plasmids or chromosomes (CMR 2017)
- Nephrotoxicity of polymyxins: is there any difference between colistimethate and polymyxin B? (AAC 2016)
- Colistin and polymyxin B: peas in a pod, or chalk and cheese? (CID 2014)
- Top 5 unanswered questions with invasive drug-resistant Gram negative infections (2016)
- Polymyxin B & colistin tips sheet from Stanford Medicine
- Detailed polymyxin information from antimicrobe.org