Objective: To compare trough and peak serum gentamicin concentrations in neonatal patients using two dosing regimens.
Method: A retrospective audit of gentamicin serum concentrations obtained with the current neonatal gentamicin-dosing regimen (regimen 1) was conducted. Results were then compared with the introduction of a new regimen (regimen 2). Preliminary results necessitated a change to a further dosage schedule (regimen 3), where data was again collected.
Results: For regimen 1, 79% of patients achieved satisfactory trough concentrations, 30% achieved satisfactory peak concentrations, and 16% achieved a satisfactory combined trough and peak concentration. For regimen 2, 80% of patients achieved satisfactory trough concentrations, 63% achieved satisfactory peak concentrations, and 48% achieved a satisfactory combined trough and peak concentration. For regimen 3, 76% of patients achieved satisfactory trough concentrations, 56% achieved satisfactory peak concentrations, and 45% achieved a satisfactory combined trough and peak concentration.
Conclusion: Regimen 3 shows a marked improvement in serum gentamicin concentrations. However neonates in the 32-38 weeks post-conceptional age group achieved higher trough and peak serum gentamicin levels than expected. Therefore the dosage interval in this group of neonates will be increased from 18 hourly to 24 hourly dosing, and regimen reaudited.