Pharmacokinetics of cefpodoxime proxetil in healthy young and elderly volunteers.

The influence of age on the pharmacokinetics of cefpodoxime was evaluated in 12 elderly (ages 65-85 years) and 12 weight- and sex-matched young (ages 20-33 years) subjects, each of whom received two cefpodoxime proxetil 200-mg tablets every 12 hours for 14.5 days. Serial blood samples and urine were collected after the first dose on day 1, after the morning dose on day 8, and after the last (morning) dose on day 15. Plasma and urine samples were assayed for cefpodoxime concentrations using HPLC methods. Within each age group, mean pharmacokinetic parameters determined on day 1 were similar to corresponding values on days 8 and 15, indicating that cefpodoxime does not accumulate after twice-daily 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 excretion and renal clearance of cefpodoxime were significantly lower in elderly subjects. Differences in renal clearance were attributed to the corresponding age-related reduction that was noted in creatinine clearance values, whereas the lower urinary excretion of cefpodoxime probably reflected slightly reduced systemic drug absorption in the elderly. 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.