[Pharmacokinetic, bacteriological and clinical studies of ceftizoxime in neonates and low birth weight infants].

Ceftizoxime (CZX), one of the fifth group in cephem-antibiotics classified by Fujii, was administrated intravenously with a one shot dose of 20 mg/kg to neonates and low birth weight infants with ages ranged 4-21 day old and plasma and urinary concentrations and urinary recovery rates of the drug were determined. Clinical, prophylactic and bacteriological effects of CZX were evaluated and adverse reactions and effects on laboratory test values due to this drug were studied in 22 neonates and low birth weight infants (0-76 day old) consisting of 16 cases with various bacterial infections including presumptive cases of bacterial infections and 6 cases with prophylactic administration against infectious diseases. An average CZX daily dose of 55.3 mg/kg was given once or divided into 2-4 times daily (twice: 16 cases, 3 times: 3 cases, 4 times: 2 cases) through intravenous one shot administration for 6 days on the average. The results obtained are summarized as follows. 1. Neonates and low birth weight infants were classified into 3 groups by age: 4-7, 8-14, 15-21 day old. Plasma peak levels of CZX were observed at an average of 5 minutes after administration in all 3 groups with mean values of 58.3, 74.9 and 76.9 micrograms/ml, respectively, and the 4-7 day old-group showed a lower value than with other 2 groups. Mean values of AUC were 218.9, 221.0 and 197.0 micrograms.hr/ml, respectively, and no notable difference was observed within each group. Mean values of half-lives of CZX were 3.61, 2.72 and 2.37 hours, respectively, and the younger group tended to have the longer value. 2. Urinary concentrations of CZX ranged 10.9-1.190 micrograms/ml in all of the 3 groups during 0-2, 2-4, 4-6, 6-8 hours after administration. Mean values of urinary recovery rates during 8 hours of the 3 age-groups were 60.1, 68.7, 56.7%, respectively. The oldest group showed the lowest mean value because one of the cases had the lowest value of 34.5% for an unknown reason. 3. Clinical effect of CZX in 16 cases with various bacterial infections and presumptive bacterial infections was evaluated with an efficacy rate of 87.5%. The prophylactic effect was recognized in all 6 cases that were given CZX to prevent infectious diseases. 4. The bacteriological effect was evaluated in only one case with an infection due to Escherichia coli, which was eradicated by the treatment.(ABSTRACT TRUNCATED AT 250 WORDS)