Background and Importance The pharmacokinetic/pharmacodynamic (PK/PD) target for vancomycin has recently been defined as an area under the curve (AUC) over 24 hours/minimum inhibitory concentration (MIC) of 400-600.

Aim and Objectives To evaluate the degree of concordance of recommendations after dose adjustment of vancomycin according to minimum plasma concentration (Cmin) and AUC/MIC ratio.

Material and Methods Retrospective study in adult patients who were treated with vancomycin administered by intermittent perfusion and monitored by the Pharmacy Service at a general hospital during the month of August 2022.

Variables collected: sex, age, weight, height, glomerular filtration rate (according to Cockcroft-Gault), total daily dose and recommendation issued based on the determination of Cmin and AUC/MIC.

Appropriate Cmin were considered 15-20µg/mL in complicated infection (endocarditis, nosocomial pneumonia, meningitis, osteomyelitis/osteoarticular infection and wound infection/abscess) and 10-15µg/mL in all other infections. For the calculation of AUC/MIC, MIC=1µg/mL was assumed. Interpretation of plasma level and individualised vancomycin adjustment was performed using MediWare Pharm++® software using a bicompartmental model and a single vancomycin level (Cmin).

Results Vancomycin treatment was initiated and monitored in 42 patients (52.4% female; 72.3 ± 12.3). Anthropometric parameters (weight: 81.8 ± 17.9kg; height: 163.8 ± 7.9cm; glomerular filtration rate: 61.5 ± 27.0ml/min/1.73m2); total daily dose: 1,878.5mg ± 524.8mg. The recommendation issued was concordant via Cmin and AUC/MIC in 35.7%. In the case of discordance, overexposure was observed in 66.6% of cases.

Conclusion and Relevance Approximately 2 out of 3 recommendations were discordant according to the method used, with a high number of overexposures observed in the case of recommendations based on Cmin. Therefore, despite the small sample size, the implementation of vancomycin therapeutic monitoring according to AUC is considered necessary for the optimisation of therapeutic management.

Conflict of Interest No conflict of interest