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Extended interval dosing of gentamicin in premature neonates ≤ 28-week gestation


Kamran Yusuf, M.D., Rm 2273, Health Sciences Center, 3330 Hospital Drive NW, Calgary, Alberta, T2N 4N1, Canada.
Tel: 403-210-3930 |
Fax: 403-283-6151 |


Aim:  To evaluate an extended interval dosing (EID) regimen of gentamicin in neonates ≤28-week gestation.

Methods:  In 2008, an EID regimen for gentamicin was introduced for all neonates admitted to the NICU in Calgary. The dosing interval was based on a 22 h level after the first dose of 5mg/kg. We conducted an observational study in 33 infants ≤28-week gestation on the EID regimen from the first day of life and compared gentamicin peak and trough levels with a historical control of 34 infants who received gentamicin in a dose of 2.5 mg/kg every 24 h (TID, traditional interval dosing).

Results:  In the EID group, based on the 22 h level, dosing interval was 36 h in 20 neonates and 48 h in 13 neonates. All neonates, except one, achieved therapeutic peak and trough levels. Compared to the TID group, the EID group had higher peak levels (median 9.8 μg/mL vs. 4.6 μg/mL, p < 0.001) with no difference in trough levels. With target peak levels of 5–12 μg/mL and trough levels of <2 μg/mL, a higher proportion of neonates in the TID group would need dose adjustment.

Conclusion:  In neonates ≤ 28-week gestation, an EID regimen from day one of life, using a single level 22 h after the first dose for dosing interval, achieves therapeutic peak and trough levels and more optimum peak levels as compared to a TID regimen.