[Pharmacokinetic, bacteriological and clinical studies on cefozopran in neonates]

Cefozopran (CZOP) was administered to nine newborn patients with infections at a dose of 20 mg/kg twice or three times daily for 5 to 6 days to evaluate the efficacy, safety and pharmacokinetics of cefozopran. 1. Blood concentrations CZOP was intravenously given to 6 newborn patients by drip infusion at a dose of 20 mg/kg over 30 minutes. The maximum blood concentrations (Cmax) were 38.4 micrograms/ml in a patient aged 0 day, 37.7 and 54.3 micrograms/ml in two patients aged 1 day, 51.3 and 64.1 micrograms/ml in two patients aged 3 days and 51.0 micrograms/ml in a patient aged 5 days. Cmax was lower in the patient aged 0 day. The elimination half life (T 1/2) was 9.2 hours in the patient aged 0 day, 4.9 and 3.7 hours in the patients aged 1 day, 3.1 and 2.4 hours in the patients aged 3 days and 2.9 in the patient aged 5 days, showing a prolongation of T 1/2 in patients of lower age. 2. Urinary excretion Of the 6 patients given CZOP at a dose of 20 mg/kg by intravenous drip infusion over 30 minutes, urine was collected in 5 patients. The cumulative excretion rate within 6 hours after infusion was as low as 19.8% of dose in the patient aged 0 day. The rates were elevated as high as 46.3 and 57.0% of dose in the patients aged 1 day. In the patient aged 3 days, the recovery within 4 hours after infusion was 47.3%. It was 70.6% of dose within 6 hours after dosing in the patient aged 5 days. The urinary recovery within 6 hours after dosing increased with the advance of age. 3. Clinical results Efficacy was evaluable in 7 patients. Of them, 3 had suspected septicemia, 2 pneumonia, 1 intrauterine infection and 1 urinary tract infection. The clinical efficacy was judged "excellent" in all the evaluable patients. Neither adverse drug reactions of signs and symptoms nor abnormal alterations of the laboratory test values were recognized in the 9 patients evaluable for safety. These results suggest that CZOP is an effective and safe drug for treatment of infections in the newborns. As for the dosage and method of administration from the view of the pharmacokinetic data obtained, intravenous drip infusion of 20 mg/kg once or twice daily was considered to be sufficient for patients aged 0 day. For patients aged 1 to 7 days and those aged 8 days or elder, the administration of twice to 3 times daily and 3 to 4 times daily were considered to be sufficient, respectively.