Once versus twice daily dose of gentamicin therapy in Thai neonates

To compare the peak and trough gentamicin concentrations in neonates after a once (ODD) vs. twice daily dosing (TDD) to establish the appropriate dosage for Thai neonates.

Neonates of gestational age > or = 34 weeks, or body weight > or = 2000 g, suspected of having bacterial infection were randomized to receive gentamicin intravenously, either 5 mg/kg every 24 hours or 2.5 mg/kg every 12 hours. The peak and trough serum gentamicin levels (SGLs) were measured. Serum creatinine cued nephrotoxicity.

Neonates were evaluated and baseline characteristics between the groups were compared. The ODD and TDD group had a mean gentamicin peak and trough concentration of 10.1 +/- 3.0 vs. 7.8 +/- 2.0 microg/ml (p < 0.05) and 1.6 +/- 1.1 vs. 2.6 +/- 1.2 microg/ml (p < 0.05), respectively. The peak SGL of > or = 4 microg/ml was achieved in 100% vs. 96% of the ODD vs. TDD group, respectively. SGL troughs > or = 2 microg/ml were detected less often in the ODD group (22% vs. 68%, p < 0.05). Abnormal change in serum creatinine was not observed in either group.

A once daily dose of gentamicin 5 mg/kg achieved a significantly higher peak SGL and safer trough than a twice-daily dose of 2.5 mg/kg albeit about a quarter of the ODD group had high troughs. A single daily dose of gentamicin 3.5-4 mg/kg/d in Thai neonates should be tested.