Gentamicin Pharmacokinetics in Neonates Undergoing Therapeutic Hypothermia for Hypoxic Ischemic Encephalopathy.

Purpose: The purpose of this study was to review the pharmacokinetic profile of gentamicin among neonates with hypoxic ischemic encephalopathy (HIE) undergoing therapeutic hypothermia (TH) treatment.

Methods: This was a retrospective study of neonates with HIE undergoing TH in the neonatal intensive care unit who received gentamicin between 2009 and 2014. Demographic information, diagnoses, laboratory test results, and medication administration and monitoring information were collected, and data were analyzed using SciPy.

Results: A total of 57 neonates were analyzed. The median birth weight was 3.25 kg (interquartile range [IQR] 2.8-3.68), and median gestational age was 39 weeks (IQR 38-40). An elevated gentamicin trough level (defined as > 2 mg/L) was observed in 61% (35/57) of neonates. Half of the neonates (49%) had multiple gentamicin trough levels obtained, and 4% of the neonates were switched to an alternate agent. There was a significant difference in the number of dosing interval changes in neonates with elevated gentamicin trough levels compared with those with therapeutic gentamicin trough levels (P < 0.001). Of the neonates with elevated gentamicin trough levels, 14% (5/35) failed their hearing screen (P = 0.389).

Conclusions: Neonates with HIE undergoing TH may have an altered pharmacokinetic profile, requiring multiple blood draws so medication levels can be monitored and doses adjusted. Traditional gentamicin dosing regimens may not be ideal for this patient population, and further guidance is required for alternative treatment regimens.