Pharmacokinetics and Target Attainment of ß-lactam Antibiotics in Older People: A Systematic Review of Current Literature.

Background And Objective: (Patho)physiological changes in older people may influence the pharmacokinetics (PK), and consequently the target attainment, of ß-lactam antibiotics using standard dosing regimens. This systematic review compiles the current knowledge on the PK and target attainment of ß-lactam antibiotics in older people, with the aim to identify priorities for dose optimization in this patient population.

Methods: A systematic literature search of the PubMed and EMBASE databases was conducted. Relevant articles published prior to 1 December 2021 were identified as eligible when they included data on the PK of ß-lactam antibiotics in adults ≥ 65 years of age. Extracted information included reported PK parameters (volume of distribution, clearance [CL], elimination rate constant, intercompartmental CL, elimination half-life, area under the concentration-time curve, maximum and trough concentration), covariates on PK parameters, target attainment rate, and dosing recommendations.

Results: Ninety-one relevant articles were included in this review. Four main ß-lactam subclasses were represented: 59.3% on cephalosporins + cephamycins, 25.3% on penicillins, 15.4% on carbapenems, and 3.3% on monobactams; 65.9% of articles involved intravenous administration, 16.5% mixed administration routes, 12.1% oral administration, and 5.5% intramuscular administration. The majority of studies had a small sample size, often did not include detailed information on the study population and methods, and were fairly old. CL was, on average, decreased, while elimination half-life was prolonged in aged subjects compared with young subjects. Volume of distribution was generally similar between age groups. Most studies identified renal function as the most important contributor to altered drug CL. In only 30.8% of the articles, target attainment was studied, and in 35.7% of these articles, target attainment was found to be suboptimal. Dosing recommendations were incorporated in 87.9% of articles.

Conclusion: Studies frequently fail to provide an evidence-based dosing recommendation for this diverse patient population. Model-based PK studies that address both physiological and disease-related changes are urgently needed. This review identified gaps of knowledge to set priorities for further research.