Disclaimer In an effort to expedite the publication of articles related to the COVID-19 pandemic, AJHP is posting these manuscripts online as soon as possible after acceptance. Accepted manuscripts have been peer-reviewed and copyedited, but are posted online before technical formatting and author proofing. These manuscripts are not the final version of record and will be replaced with the final article (formatted per AJHP style and proofed by the authors) at a later time. Purpose To describe the implementation and operationalization of a β-lactam (BL) therapeutic drug monitoring(TDM) program at a large academic center. Summary BLs are the most used class of antibiotics. Suboptimal antibiotic exposure is a significant concern in hospitalized patients, particularly in those with altered pharmacokinetics. BL-TDM provides clinicians the opportunity to optimize drug concentrations to ensure maximal therapeutic efficacy while minimizing toxicity. However, BL-TDM has not been widely adopted due to the lack of access to assays. The University of Florida Shands Hospital developed a BL-TDM program in 2015. This is a consultative service primarily run by pharmacists and is conducted in all patient care areas. An analysis was performed on the first BL-TDM encounter for 1,438 patients. BL-TDM was most frequently performed for cefepime (61%, n = 882), piperacillin (15%, n = 218), and meropenem (11%, n = 151). BL-TDM was performed a median of 3 days (interquartile range, 1-5 days) from BL initiation. Among patients with available minimum inhibitory concentration (MIC) values and trough concentrations, the pharmacokinetic/pharmacodynamic (PK/PD) target of 100% fT>MIC was attained in 308 patients (88%). BL-TDM resulted in a dosage adjustment in 25% (n = 361) of patients. Conclusion Implementation of a BL-TDM program requires the concerted efforts of physicians, pharmacists, nursing staff, phlebotomists, and personnel in the analytical laboratory. Standard antibiotic dosing failed to achieve optimal PK/PD targets in all patients; utilizing BL-TDM, dose adjustments were made in 1 of every 4 patients.

Background Beta-lactams (BL) are the cornerstone of antimicrobial treatment for infections. Beta-lactam therapeutic drug monitoring (BL-TDM) optimizes drug concentrations to ensure maximal efficacy and minimal toxicity. The goals of this study were to describe the implementation process of a BL-TDM program and to further describe our experience using BL-TDM in clinical practice. Methods This was a retrospective review of adult patients with available BL-TDM between January 2016 and November 2019 at the University of Florida (UF) Health Shands Hospital. Total serum concentrations of BL were measured in the Infectious Diseases Pharmacokinetics Lab (IDPL) at UF, using a validated ultrahigh pressure liquid chromatography assay with triple quadrupole mass spectroscopy (LC-MS-MS). At our institution, TDM is available for 11 BLs and in-house assays are performed from Mon-Fri for most BLs. Results A total of 3,030 BL concentrations were obtained. An analysis was performed on the first BL-TDM encounter in 1,438 patients. The median age was 57 years (IQR, 41-69) and the median BMI was 27.5 kg/m2 (IQR, 22.5-34.5). On the day of BL-TDM, the median serum creatinine was 0.83 (IQR, 0.59-1.30). Fifty-one percent of patients (n=735) were in an ICU at the time of BL-TDM with a median SOFA score of 6 (IQR, 3-9). BL-TDM was most frequently performed on cefepime (61%, n=882), piperacillin (15%, n=218), and meropenem (11%, n=151). The BL was administered as a continuous infusion in 211 (15%) patients. An interim analysis of 548 patients showed that BL-TDM was performed a median of 2 days (IQR, 1-4) from the start of BL therapy and resulted in a dosage adjustment in 26% (n=145). Conclusion BL-TDM was performed in older, non-obese patients with normal renal function. Over half of the evaluated patients were in an ICU at the time of TDM. This finding emphasizes the value of BL-TDM in the ICU setting because altered pharmacokinetics during critical illness has been linked to enhanced BL clearance. Interestingly, BL-TDM resulted in dosage adjustment in 1 in 4 patients who were receiving licensed BL dosing regimens, thus highlighting the role of TDM in dose individualization. BL-TDM was performed most commonly within the 72-hours of therapy initiation. Early BL-TDM has been shown to improve patient outcomes and should be promoted. Disclosures Venugopalan Veena, PharmD, Melinta (Other Financial or Material Support, Received a stipend for participation in a drug registry)Merck (Other Financial or Material Support, Received a stipend for participation in a drug registry) Charles A. Peloquin, Pharm.D., Nothing to disclose