Pharmacokinetics of ornidazole in neonates and infants after a single intravenous infusion

Summary

The single dose pharmacokinetics of ornidazole has been evaluated in 12 neonates or infants (aged 1 to 42 weeks) after the infusion of 20 mg/kg over 20 min. Plasma disposition was described by a two-compartment open model. The distribution phase was short (T_1/2 (1)=0.31 h) and was followed by an elimination phase (t_1/2 (2)=14.67 h). The mean apparent volume of distribution was 0.96 l/kg⁻¹. These results did not differ from data previous by reported in adults. Total plasma clearance was between 0.4 and 1.4 ml·min⁻¹·kg⁻¹. The plasma concentration 24 h after the infusion was 7.32 mg·l⁻¹, which was above the minimum inhibitory concentration for clinically significant anaerobic bacteria. Based on the pharmacokinetic results and residual concentrations at 24 h, a single daily infusion of ornidazole 20 mg·kg⁻¹ appears adequate for therapy in neonates and infants.