Validation of a Simplified Netilmicin Dosage Regimen in Infants

Abstract

The aim of this study was to validate a simplified high-dosage, extended-interval netilmicin dosage regimen for infants. A total of 129 infants receiving 163 treatment courses of netilmicin (6 mg/kg every 24 or 36 h depending on gestational age (GA), postnatal age and postmenstrual age) was analysed. Serum netilmicin concentrations were monitored before (C_min), 30 min (C_0.5h) after and 7.5 h (C_7.5h) after the third dose. In 110 patients during first week of life mean C_0.5h was 10.5 mg/l. Mean C_0.5h was significantly lower (9.0 mg/l) in 38 infants older than 1 week of age. 14 of 15 patients with C_min levels≥2 mg/l receiving netilmicin every 36 h were <28 weeks of gestation. In the first week of life significant correlations between GA and elimination half-life (p<0.001) and between plasma creatinine and elevated C_min (p<0.002) were found, but no correlation between C_0.5h and GA. In this high-dosage regimen a dosing interval of 48 h for GA<29 weeks, 36 h for GA 29–36 weeks and 24 h for full term babies seems appropriate, during first week of life, to avoid the majority of elevated trough levels and still obtain maximal therapeutic efficacy.