1988 Volume 41 Issue 3 Pages 262-275
1. Ten neonates 0 to 28 days old (gestation: 37-42 weeks; birth weight: 2, 160-3, 640g) received 20mg/kg CTRX (8 cases) or 10mg/kg (2 cases) by intravenous bolus injection, while 9 infants 35 days to 9 months old (gestation: 37-43 weeks; birth weight: 2,800-3,560g) received 20mg/kg by intravenous bolus injection, and their blood drug concentrations and urinary drug excretions were examined.
Average blood levels of CTRX in the 20mg/kg dosage group were 114±14.6μg/ml at 30 minutes, 109±12.8μg/ml at 1 hour, 100±12.6μg/ml at 2 hours, 87.9±15.8μg/ml at 4 hours, 72.8±15.3μg/ml at 6 hours, and 50.1±12.3μg/ml at 12 hours in the neonates; and 11320.0 g/ml at 30 minutes, 101±14.7μg/ml at 1 hour, 83.6±9.3μg/ml at 2 hours, 70.3±10.7μg/ml at 4 hours, 56.9±8.6μg/ml at 6 hours, and 35.7±9.2μg/ml at 12 hours in the infants.
Average half-lives of CTRX in blood were 10.3±4.5 hours in the neonates, and 6.6±1.9 hours in the infants.
Average blood concentrations of CTRX in the 10mg/kg dosage neonate group were 63.8±6.0μg/ml at 30 minutes, 57.8±2.5μg/ml at 1 hour, 53.5±0.7μg/ml at 2 hours, 41.8±7.4μg/ml at 4 hours, 32.4±5.9μg/ml at 6 hours, and 20.8±1.1μg/ml at 12 hours, and the half-life was 7.2±0.4 hours.
These results suggest that blood concentrations are apparently dose-related in the neonate period; that the peak levels of the neonate and infant groups were similar (the levels at 30 minutes) not showing a relationship to age, gestation period or to birth weight; and that the higher the age was the shorter the half-life became with the half-life in the one week old group was 1.5 times as long as that in the older infant group. The half-life in the younger infant group, however, was similar to that in the older infant group.
Urinary excretion was examined in 4 neonates and 2 infants. Average urinary recovery rates in 12 hours after intravenous injection were 40.8±8.3% in the neonate group and 44.8±12.8% in the infant group, showing that CTRX is excreted well even in the neonate period.
2. CTRX was administered into 13 neonates with bacterial infections (age: 0-26 days), and the clinical efficacy, bacteriological efficacy, and side effects were examined. In principle, 20mg/kg was given once or twice a day for neonates aged up to 7 days, and twice for those aged 8 days or more.
The clinical efficacies in 5 with acute pneumonia, 3 with acute bronchitis, 2 with acute urinary tract infection, and 1 case each with suspected sepsis, periproctal abscess and staphylococcal scalding skin syndrome were excellent in 9 cases, good in 3 and fair in 1 (efficacy rate: 92.3%).
Concerning bacteriological efficacy, 1 strain each of pathogens Staphylococcus aureus, Staphylococcus epidermidis, Streptococcus agalactiae, Haemophilus influenzae, Klebsiella pneumoniae, and 2 strains of Escherichia coli, were all eradicated except S. aureus which was reduced; the eradication rate was 85.7%.
No side effects were noted in any of the cases. As laboratory abnormalities, eosinophilia, thrombocytopenia and elevation of GOT were observed in 1 case each, but these findings were confirmed normal on a follow up retest.
The above results show that CTRX is a useful and safe drug even in the neonate period.
