Empirical gentamicin dosing based on serum creatinine levels in premature and term neonates

Empirical gentamicin dosing based on serum creatinine (SCr) levels in premature and term neonates was evaluated.

This single-center, retrospective cohort study was conducted in a standalone children's hospital with a level IIIB, 44-bed neonatal intensive care unit (NICU). Data were abstracted and collected for all neonates admitted to the NICU from March 5, 2012, through March 5, 2014. Patients were included in the study if gentamicin was administered within the first 7 days of life, a trough gentamicin level was measured, and the neonate had a baseline SCr level measured within the first 24 hours of life. A series of logistic regressions was conducted to determine if gentamicin trough levels were influenced by gestational age (≤29 weeks [group 1], 30 weeks to 34 weeks and 6 days [group 2], and ≥35 weeks [group 3]) and SCr level (0.81-0.99 mg/dL [mildly elevated] and ≥1 mg/dL [elevated]).

Of the 577 neonates reviewed during the study period, 507 met the inclusion criteria. Mildly elevated and elevated SCr levels were significantly associated with the presence of an elevated gentamicin trough (p < 0.001). When the effect of gestational age was evaluated, the data suggested that SCr is a strong predictor of elevated gentamicin troughs.

Neonates with a gestational age of ≥30 weeks who had an SCr level of ≥1 mg/dL within the first 12-24 hours of life were more likely to have an elevated gentamicin trough level than their counterparts with normal SCr levels.