Abstract
The fundamental trials on intravenous administration of tobramycin (TOB) were studied in a total number of 29 neonates and premature babies who was divided into 3groups by their ages; 0-3, 4-7 and 8 or more days after birth. Moreover, the results obtained in them were compared with those in a small number of infants and the school children reported previously to investigate the possibility of administration of the drug to neonates and premature babies.
1. Analysis of the pharmacokinetics of TOB in neonates and premature babies demonstrated that its halflife (T1/2) became shorter with age; it was 5.37, 4.28 and 3.03 hours at the age of 0-3, 4-7 and 8 or more days, respectively when 1.5mg of the drug per kg body weight is instilled into the vein for 30 minutes. A similar trend was observed at a dose of 3.0mg per kg body weight.
2. Although the number of subject was small, T1/2 averaged 2.07hours at the dose of 1.5 mg/kg in 2 infants and 1.40hours at 3.0mg/kg in 3 infants.
These results indicate that administration of TOB based on the same conception as that in infants and school children should be avoided in neonates and premature babies.
Especially in0-3, 4-7day-old neonates and premature babies the behavior of the drug in the body suggests that once or twice administration a day may be safer and better to avoid its accumulation.
The peak serum concentrations in neonates and premature babies were slightly higher with decrease in number of days after birth, but it was not specially high as compared with those in infants and school children. It is, therefore considered that 1.5mg/kg is an adequate single dose to moderate cases.
On the basis of the above-mentioned results of the pharmacokinetic study we are confirming the clinical safety and utility of TOB in cases in which its administration is essential.
