Background and Importance Data about the efficacy and toxicity of vancomycin used by continuous infusion (CI) compared to intermittent infusion (II) are still controversial.

Aim and Objectives To compare the profile of patients treated with II or CI of vancomycin and the frequency of nephrotoxicity within a therapeutic drug monitoring (TDM) programme.

Material and Methods Retrospective pharmacokinetic (PK) study in adult patients treated with II/CI of vancomycin and undergoing TDM in a university hospital during 2022.

Data collected demographics, clinical (serum creatinine (Cr) and estimated glomerular filtration rate (CKD-EPI) (eGFR) at baseline and end of treatment) and pharmacokinetic data (PK).

TDM samples: before dose (Cmin,ss) and 1h after the end of the intravenous infusion (Cmax,ss) (II) or at any time (Css) (CI). Mean area under the curve in plasma (AUC24h) was estimated by a Bayesian software.

Results Patients included: 128: 62.7(14.6) years, 88(68.8%) males, 61 (47.7%) directed treatments. Most frequent pathogens: 22 (17.2%) S . epidermidis, 14 (10.9%) E. faecium and 7 (5.5%) MRSA.

Conclusion and Relevance

• The use of continuous infusion of vancomycin was more frequent among ICU patients, with septic shock and lower baseline serum creatinine.

• The CI group had better renal function at the end of vancomycin treatment and seem to have a lower nephrotoxicity rate.

• Patients treated with CI had a higher severity status (they were more frequently severy-ill and sepsis), what probably could explain the higher in-hospital mortality rate observed. However, more data are needed to study the efficacy and safety of this strategy.

Conflict of Interest No conflict of interest