Clinical pharmacology of netilmicin in the newborn

The plasma peak, trough, and peak-trough concentrations of netilmicin given to preterm and term infants were measured after different regimens to determine which dosage would provide satisfactory peak and trough concentrations. In infants aged less than 7 days, dosage regimens of 3.0 or 2.5 mg/kg every 12 hours gave satisfactory peak levels (range 5.2-12.0 micrograms/ml) but troughs were above the desirable maximum level of 3 micrograms/ml in more than half the preterm infants. Subsequently a dosage regimen of 3.0 mg/kg immediately followed by 2.0 mg/kg every 12 hours resulted in trough levels that exceeded 3 micrograms/ml in only 2 of 25 preterm determinations and never in term infants, yet gave satisfactory peak levels (range 4.5-7.4 micrograms/ml). In preterm infants aged 4 to 7 weeks a dosage of 3 mg/kg every 8 hours gave satisfactory peak and trough levels.