Pharmacokinetics and clinical evaluation of aztreonam in pediatric surgery

Pharmacokinetic and clinical studies on aztreonam (AZT) in pediatric surgery were performed and results obtained are summarized below. 1. Plasma and urinary levels of AZT were measured in 6 neonate patients following drip-infusion for 1 hour of AZT (dose of AZT: 20 mg/kg). Plasma levels reached their peak (42.3-50.4 micrograms/ml) at the end of infusion or in 1 hour thereafter except in case 2. In case 2, plasma level reached its peak (36.6 micrograms/ml) at 2 hours after the end of infusion. Plasma levels of AZT decreased rapidly after reaching their peaks, and plasma half-lives (T 1/2) were 1.85-2.84 hours. Urinary recovery rates were 15.7-65.3%. 2. Bile levels of AZT were determined in 8 patients with biliary atresia following 1 hour drip-infusion of AZT (dose of AZT: 20 mg/kg for 4 patients, 40 mg/kg for the other 4 patients). In the 20 mg/kg group, peak levels of AZT in bile were noted 2 hours after the end of infusion, and they were 3.7-7.1 micrograms/ml. Recovery rates in bile in the first 6 hours after the end of infusion were 0.34-0.9%. In the 40 mg/kg group, peak levels of AZT in bile were found at 2 hours and 2-4 hours after the end of infusion, and they were 4.9-8.8 micrograms/ml. Recovery rates in bile in the first 6 hours after the end of infusion were 0.03-0.33%. 3. AZT and ampicillin were administered to 6 patients as prophylaxis against postoperative infections. Another patient with postoperative cholangitis was given AZT alone.(ABSTRACT TRUNCATED AT 250 WORDS)