Factors affecting the initial serum concentration of teicoplanin in pediatric patients: A single-center retrospective analysis

Background The glycopeptide antibiotic teicoplanin (TEIC) is used to treat infections caused by methicillin-resistant Staphylococcus aureus and other gram-positive bacteria. Because higher target trough concentrations are now recommended, higher loading dose (LD) regimens have been proposed. However, the factors affecting Ctrough levels and the safety of high-dose regimens remain unclear. This study aimed to investigate the factors that should be considered in the loading dose (LD) regimen of TEIC in pediatric patients and assess the safety of a higher LD. Methods We enrolled pediatric patients aged 1–14 years with available TEIC concentrations measured between August 2013 and December 2024. Factors affecting the initial Ctrough and the initial Ctrough divided by LD per kilogram of body weight (C/D ratio) were investigated. Safety assessment included serious adverse reactions at the time of initial Ctrough measurement. Results In total, 108 patients were enrolled in this study. Of 108 enrolled patients, 64 patients were measured initial Ctrough on day 4. Fifty-four patients received higher LD (average 54.2 mg/kg/3 days) than the standard regimen, with 33 patients (52%) not achieving an initial Ctrough of 15 μg/mL. Linear regression analysis showed that the initial Ctrough was associated with age (p = .008), eGFR (p < .001), and serum albumin level (p = .017). The C/D ratio on day 4 was associated with eGFR (p < .001) and the presence or absence of febrile neutropenia (FN) (p = .046). Further analysis restricted to patients with FN indicated that bone marrow transplantation (BMT) (p = .046) affected the C/D ratio. Serious adverse reactions occurred in five cases. Conclusions Clinical conditions, such as FN and BMT, which cause an increase in eGFR, may affect the initial Ctrough in pediatric patients. Moreover, a higher LD was well-tolerated. When determining the LD, clinical conditions must be considered.