The pharmacokinetics of cefpodoxime were evaluated in 30 paediatric patients (12 females and 18 males, 1.0 to 17.2 years of age) with normal renal and hepatic function following a single oral dose (4.5 ± 0.8 mg/kg, range 2.7 to 5.0 mg/kg) of cefpodoxime proxetil. Cefpodoxime was quantitated from repeated blood and urine samples obtained over a 12-hour postdose period by HPLC. Apparent peak plasma cefpodoxime concentrations ranged between 0.8 and 3.4 mg/L (2.2 ± 0.6 mg/L), and were observed between 2 and 4 hours following drug administration. A lag-time (0.46 ± 0.26 hours, range 0 to 1.1 hours) was evident in 27 of 29 subjects. Mean (± SD) values for the absorption rate constant (Ka), absorption half-life (t½Ka), and time for 90% absorption were 0.84 ± 0.44h−1, 0.82h and 3.6 ± 0.6h, respectively. Values for the elimination rate constant (Kel), apparent total plasma clearance (CL/F) and apparent steady-state volume of distribution (Vdss/F) were 0.41 ± 0.06h−1, 0.42 ± 0.15 L/h/kg (range 0.16 to 0.93 L/h/kg) and 1.08 ± 0.49 L/kg (range 0.47 to 2.9 L/kg), respectively. The mean renal clearance (CLR) for cefpodoxime in 18 subjects was 0.11 L/h/kg and represented 26% of the mean CL/F. Inverse linear correlations were found between patient age and both CL/F (r = 0.67, p < 0.001) and Vdss/F (r = 0.55, p < 0.01), thus demonstrating developmental dependence for these 2 parameters. Accordingly, when CL/F, Vdss/F and Kawere compared between patients less than 5 years of age and those aged 5 years or more, significant differences were found (i.e. 0.57 ± 0.16vs0.36 ± 0.1 L/h/kg for CL/F, 1.52 ± 0.56vs0.89 ± 0.3 L/kg for Vdss/F and 1.12 ± 0.77vs0.73 ± 0.18h−1for Ka); the larger values for each parameter being seen in the youngest age group. These data support a developmental dependence in the disposition of cefpodoxime in paediatric patients following the administration of the prodrug ester, cefpodoxime proxetil.