[Pharmacokinetic, bacteriological and clinical evaluation of tazobactam/piperacillin in pediatrics]

Pharmacokinetic, bacteriological and clinical studies were performed in pediatrics on tazobactam/piperacillin (TAZ/PIPC), a combined drug of a new beta-lactamase inhibitor tazobactam and piperacillin at a ratio of 1:4. 1. Serum levels and urinary excretions of TAZ, PIPC and desethyl piperacillin (DEt-PIPC), a metabolite of PIPC, after one shot intravenous administration of 50 mg/kg of TAZ/PIPC to two children (6-7 years old) were investigated. The serum TAZ level at 0.08 hour was 50.8-51.0 micrograms/ml after administration. Then TAZ concentrations gradually decreased with half-lives of 0.38-0.45 hour, and reached 1.0-1.4 micrograms/ml after 2 hours and was not detected after 3 hours and 6 hours. Serum PIPC levels at 0.08 hour was 167.0-231.0 micrograms/ml after administration. Then PIPC concentrations gradually decreased with half-lives of 0.41-0.55 hour, and reached 1.2-2.4 micrograms/ml after 3 hours and was not detected after 6 hours. DEt-PIPC was detected slightly in serum. A ratio of TAZ to PIPC was about 1 to 4 in serum at each time. Urinary recovery rates of TAZ in the first 6 hours after administration of TAZ/PIPC were 33.5-90.1% and those of PIPC were 41.9-77.8% and those of DEt-PIPC were 1.5-2.8%. 2. TAZ/PIPC was administered to 27 pediatric patients (their ages ranged between 2 months and 11 years old) with various infections, and clinical and bacteriological effects and adverse reactions were investigated. Single doses were 26.2-55.6 mg/kg, frequencies of administration were 3-4 times a day, and durations of administration were 3 1/3-7 1/3 days, and total dosages were 4.5-33.75 g. Clinical effects were evaluable in 26 cases. Responses were rated as "good" in acute purulent tonsillitis 1 case and acute purulent otitis media 1 case, as "excellent" in acute sinusitis 1 case, as "excellent" in 2 and "good" in 1 out of 3 cases of acute bronchitis, as "excellent" in 13 and "good" 2 out of 15 cases of acute pneumonia, as "excellent" in acute urinary tract infection 2 cases and as "excellent" in acute enteritis in 1 case, acute appendicitis in 1 case and lymphadentis in 1 case. In all cases, the results were rated as "good" or "excellent". Antimicrobial effects against a total of 10 strains identified or assumed to be pathogenic bacteria were evaluated. The 10 strains of bacteria included 4 strains of Streptococcus pneumoniae, 3 strains of Haemophilus influenzae (2 strains beta-lactamase producing), 2 strains of beta-lactamase producing Moraxella catarrhalis, 1 strain of beta-lactamase producing Morganella morganii. All the bacteria listed here were judged to have been eradicated. Adverse reaction was observed in 1 case with mild diarrhea. As abnormal changes in laboratory data, leucocytopenia in 1 case, elevation of GOT. GPT in 2 cases and eosinophilia in 1 case were observed. On the basis of the findings, TAZ/PIPC was considered to be effective and safe in the treatment of pediatric infections.