Overview of vancomycin monitoring, drug exposure and dosage adjustment in adults
To optimise drug exposure and minimise toxicity, therapeutic drug monitoring is recommended for all patients expected to receive vancomycin for more than 48 hours.
Optimal vancomycin drug exposure in a 24-hour period needs to balance therapeutic efficacy, drug toxicity and resistance development. The recommended vancomycin drug exposure is an area under the concentration–time curve over a 24-hour period (AUC24) of 400 to 600 mg.hr/L (for infections other than central nervous system infections). Trough concentrations are only used as a surrogate for an AUC24. Directly determining AUC24 allows use of target exposures and lower vancomycin doses, which has been shown to reduce the risk of nephrotoxicity (ie acute kidney injury).
In vitro data suggest that a daily AUC24 of 400 mg.hr/L is required for effectiveness in the treatment of methicillin-resistant Staphylococcus aureus (MRSA) bacteraemia. Nephrotoxicity increases with daily and cumulative drug exposure, particularly at AUC24 exposures more than 600 to 650 mg.hr/LRybak 2020.
Minimising drug toxicity and optimising therapeutic efficacy may be difficult in S. aureus bacteraemia when the minimum inhibitory concentration (MIC) is more than 1 mg/L; seek expert advice. The recommended vancomycin AUC24 targets in these guidelines assume that the MIC is 1 mg/L.
For adults undergoing haemodialysis, see Vancomycin dosing, monitoring and dosage adjustment in adults undergoing dialysis.