[Laboratory and clinical studies on tazobactam/piperacillin in the field of pediatrics].

Laboratory and clinical studies on tazobactam/piperacillin (TAZ/PIPC), a combination drug of piperacillin (PIPC) with the new beta-lactamase inhibitor tazobactam (TAZ), were carried out in the field of pediatrics. 1. After intravenous administration of TAZ/PIPC at a dose of 25 mg/kg to one child, the peak plasma levels of TAZ and PIPC were 24.4 micrograms/ml and 119 micrograms/ml respectively after 5 min. The half-lives of TAZ and PIPC were 0.48 and 0.60 hours respectively. Same as 50 mg/kg to two children, the peak plasma levels of TAZ and PIPC were 17.5, 32.2 micrograms/ml and 92.8, 163 micrograms/ml after 5 min. The half-lives of TAZ and PIPC were 0.37, 0.50 hours and 0.51, 0.59 hours. A ratio of TAZ to PIPC was about 1 to 4 in plasma levels. The cumulative urinary recovery rates of TAZ and PIPC in the first 6 hours after intravenous administration were 15.8, 64.9% and 39.8, 53.4%. 2. The antibacterial activity of TAZ/PIPC against clinically isolated organisms was determined. The MICs of TAZ/PIPC were < or = 0.05 microgram/ml against Haemophilus influenzae and Streptococcus pneumoniae and > or = 1.56 micrograms/ml against Escherichia coli, Staphylococcus aureus and Haemophilus parainfluenzae. 3. The clinical efficacy of TAZ/PIPC could be evaluated in 14 patients with various bacterial infections, and was evaluated as "excellent" in 9 patients and as "good" in 5. The overall clinical efficacy rate in 14 cases was 100% and excellent was 64.3%. Bacteriological efficacy rate was 91.7% (10/11). 4. As a side effect, loose stool was observed in one case, no abnormal laboratory test values were observed. It has been concluded that TAZ/PIPC was a useful drug in the field of pediatrics.