Oral Antibiotic Pharmacokinetics in Young Infants

Young infants are at increased risk for serious bacterial infections, yet limited pharmacokinetic data are available to guide evidence-based dosing of oral linezolid in this population. Developmental changes in drug absorption, distribution, metabolism, and elimination during early infancy contribute to variability in drug exposure, making it difficult to optimize dosing using existing recommendations. This prospective pharmacokinetic study will enroll young infants who receive linezolid either as part of routine clinical care or as a single, one-time study dose. Blood samples will be collected to measure plasma linezolid concentrations, and demographic, clinical, laboratory, and medication data will be collected from the medical record. These data will be used to develop pharmacokinetic models and evaluate sources of variability in linezolid exposure, including developmental and clinical factors. The results of this study are expected to improve the understanding of oral linezolid pharmacokinetics in young infants and support the development of model-informed dosing strategies to optimize antibiotic exposure, maximize treatment effectiveness, and minimize toxicity in this vulnerable population.