Pharmacokinetics and clinical studies on aztreonam in neonates

Pharmacokinetic and clinical studies on aztreonam (AZT) were performed in neonates. Serum concentrations and urinary excretion of AZT were determined in 12 neonates with ages between 0 and 7 days (birth weights were between 1,260 and 3,500 g) upon intravenous injection or 1 hour drip intravenous infusion of AZT at 20 mg/kg. Serum concentrations of AZT at 1 hour after i.v. administration were 54.0 +/- 12.5 micrograms/ml, and half-lives were 6.01 +/- 0.70 hours. Serum concentrations of AZT reached their peaks at the end of drip infusion with levels of 42.1 +/- 17.6 micrograms/ml in the d.i.v. group and half-lives were 6.40 +/- 1.88 hours. Urinary recovery rates in the first 12 hours after administration were 28.5 +/- 6.4% for the i.v. group and 32.3 +/- 13.9% for the d.i.v. group. AZT was administered to 12 neonatal patients (2 cases of sepsis, 2 cases of suspected sepsis, 3 cases of pneumonia, 2 cases of urinary tract infection and 3 cases for prophylaxis), and clinical effectiveness, bacteriological efficacy and adverse reactions were evaluated. Clinical efficacies in 9 cases except 3 cases with prophylactic use were excellent in 1 case, good in 5 cases, fair in 1 case, poor in 1 case and unknown in 1 case, thus the efficacy rate was 75%. Bacteriological effects in 3 strains with Gram-negative bacilli were eradicated in 2 strains and unchanged in 1 strain, hence the bacteriological eradication rate was 66.7%. Increased GOT and GPT were observed in 1 cases as abnormal laboratory test results, but the abnormality was not serious.(ABSTRACT TRUNCATED AT 250 WORDS)