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

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 (T1/2 (1) = 0.31 h) and was followed by an elimination phase (t1/2 (2) = 14.67 h). The mean apparent volume of distribution was 0.961/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 X min-1 X kg-1. The plasma concentration 24 h after the infusion was 7.32 mg X 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 X kg-1 appears adequate for therapy in neonates and infants.