Presented at the Neonatal Society 2002 Autumn Meeting.

Pardy K¹, Scorrer T², Doherty C¹

¹ Neonatal Unit, University Hospital of Wales, Heath Park, Cardiff, UK
² Neonatal Unit, St Mary’s Hospital, Portsmouth, UK

Introduction: Gentamicin is widely used as a first line agent in the treatment and prevention of gram negative sepsis in neonates (1). Potential hazards in its use are nephro- and ototoxicity. We investigated whether our current dosing regimen for gentamicin was associated with potentially toxic trough serum levels.

Methods: A retrospective audit of gentamicin levels in infants on the neonatal unit at UHW between January and July 2000 was performed. Outcome measures were trough serum levels and monitoring for toxicity.

Results: 268 investigations of serum gentamicin were performed during the study period. High trough levels were found in 58 tests (21.6%) performed on 50 patients (57.4%). Prescription was according to protocol in 86% of infants. Infants of 24-28 weeks gestation were more likely to experience high trough levels (61%). Monitoring for toxicity was variable. Renal function tested in 78%, and all results were normal. Hearing tests were only performed in 38% of infants, all of which were also normal.

Discussion: Using a well established multiple daily dosing regimen for gentamicin, 57.4% of infants experienced potentially toxic high trough serum drug levels. This was not due to errors in prescription or dose alteration. Furthermore, not all infants were monitored for toxic effects with only 38% of exposed infants receiving a hearing test. Recent studies indicate improved efficacy and reduced toxic levels using once daily dosing of gentamicin in neonates (2). We have therefore adopted a once daily dosing regimen based on this audit which incorporates improved guidelines for the monitoring for toxicity.

References
1. Thureen, PJ., et al. Paediatrics 1999 103:594-598
2. Davies, MW., Cartwright, DW. J. Paediatr. Child Health 1988 34:577-580