A Laboratory Protocol for Routine Therapeutic Drug Monitoring of Beta-Lactams Antimicrobials in Horses and Dogs

<b>Background:</b> Although antibiotic resistance is a well-known issue in veterinary medicine, studies proposing real-time therapeutic monitoring (TDM) are lacking. The objective of the present study was to develop a simple and rapid protocol for the real-time therapeutic monitoring of antibiotics in horses and dogs. <b>Methods:</b> A reliable TDM protocol should encompass guidelines for the definition of plasma/serum collection time points, sample management by the clinical staff, transportation to the laboratory, and the availability of robust and swift analytical technologies. Ampicillin and sulbactam were quantified using liquid chromatography-tandem mass spectrometry (LC-MS/MS) in the plasma or serum of animals treated with ampicillin alone or combined with sulbactam. <b>Results:</b> The method was successfully applied to samples collected from animals hospitalized in our veterinary hospital and proved helpful in understanding the pharmacokinetics of this antibiotic in critically ill patients. <b>Conclusions:</b> Combined with minimum inhibitory concentration (MIC) data, this approach enables PK/PD evaluations to support the development of personalized therapeutic strategies and optimized dosing regimens for animals.