The pharmacokinetics and toxicity of once-daily tobramycin therapy in children with cystic fibrosis.

The pharmacokinetics and toxicity of once-daily intravenous tobramycin were studied prospectively in seven children with cystic fibrosis. Mean 1 h post-dose concentrations of 21.9 mg/L (S.D. 3.0) and 40.2 mg/L (S.D. 8.1) were achieved following tobramycin doses of 8 mg/kg and 15 mg/kg, respectively. The half-life (mean 2.3 h) was unchanged at the two doses, as were the total clearance and volume of distribution. All patients responded well to therapy. No nephrotoxicity occurred, but one patient showed transient ototoxicity.