PHARMACOKINETICS OF CEFPODOXIME PROXETIL IN HEALTHY-YOUNG AND ELDERLYVOLUNTEERS

The influence of age on the pharmacokinetics of cefpodoxime was evalua ted in 12 elderly (ages 65-85 years) and 12 weight- and sex-matched yo ung (ages 20-33 years) subjects, each of whom received two cefpodoxime proxetil 200-mg tablets every 12 hours for 14.5 days. Serial blood sa mples and urine were collected after the first dose on day I, after th e morning dose on day 8, and after the last (morning) dose on day 15. Plasma and urine samples were assayed for cefpodoxime concentrations u sing HPLC methods. Within each age group, mean pharmacokinetic paramet ers determined on day 1 were similar to corresponding values on days 8 and 15, indicating that cefpodoxime does not accumulate after twice-d aily dosing of cefpodoxime proxetil. Based on this result, parameters were pooled across days in each age group. No significant differences were observed between healthy and elderly volunteers in area under the plasma concentration-time curve for the 12-hour dosing interval, peak plasma concentration, or time to peak concentration. Mean urinary exc retion and renal clearance of cefpodoxime were significantly lower in elderly subjects. Differences in renal clearance were attributed to th e corresponding age-related reduction that was noted in creatinine cle arance values, whereas the lower urinary excretion of cefpodoxime prob ably reflected slightly reduced systemic drug absorption in the elderl y. Differences in these parameters between groups were less than 30%, and were unlikely to be of clinical importance. The data indicate that dose adjustment of cefpodoxime in elderly subjects having normal (age -adjusted) creatinine clearance values is not required.