Pharmacokinetics of azlocillin in children with cystic fibrosis.

6-E1(R)-2-(oxo-imidazolidine-1-carboxamido)-2-phenyl-acetamido]- penicillanic acid sodium salt (azlocillin, Securopen) was given in doses of 
100 and 200 mg/kg body weight to children with cystic fibrosis. 
After intravenous bolus infections, the serum half-life was 0.82 +/- 0.12 
h after the lower dose and 0.98 +/- 0.18 h after 
the higher dose. This was consequent to a dose limited elimination 
kinetics due to limitation in both renal and non-renal processes of 
elimination. Upon doubling of the dose from 100 to 200 mg/kg, 
the total body clearance dropped from 13.93 to 5.10 1/h. Evaluation 
of data presented in other publications indicate that a dose limited 
elimination kinetics is the normal situation for azlocillin. Besides, the serum 
concentrations of patients with cystic fibrosis were considerably lower than seen 
in the healthy state. The reason is faster elimination by the 
renal route in cystic fibrosis. 