Colistimethate sodium (CMS) exhibits concentration-dependent bactericidal killing (AUC/MIC = area under curve/minimum inhibitory concentration)) and is often used in combination with other antibiotics against Carbapenemase producing enterobacteriaceae (CPE) bacteria. Traditional dosing regimens for CMS do not attain serum concentrations that would be sufficient for the treatment of infections caused by pathogens with minimum inhibitory concentration (MIC) higher than 0·5 mg/L.
Studies have shown that high dose regimens are more effective with limited increase in irreversible nephrotoxicity.1 Many patients do experience nephrotoxicity but the majority recover renal function. The risk of nephrotoxicity must be balanced against the severity and potential mortality rate of the infection being treated.
The content of this guidance is based on the current UK CMS license and experience of UK specialist pharmacists using it in clinical practice.2
N.B. Always seek specialist advice before initiating treatment with CMS.
This guidance does not cover use of CMS for respiratory infections in cystic fibrosis patients.