Pharmacokinetics of oxiracetam in elderly patients after 800 mg oral doses, comparison with non-geriatric healthy subjects.

The pharmacokinetics of oxiracetam have been studied in eighteen elderly patients and in six healthy non-geriatric adults. A 800 mg single oral dose was administered in the morning of the first day and repeatedly, every 12 h, from day 2 evening to day 10 morning, to the elderly patients. The healthy non-geriatric adults were given a 800 mg single oral dose of oxiracetam. In healthy non-geriatric subjects after a single oral administration of 800 mg, the normalized plasma levels of oxiracetam for 1 mg/kg dose were similar to those already recorded after a 2000 mg single dose of oxiracetam. Therefore, there was no tendency towards non-linear pharmacokinetics of oxiracetam between 800 and 2000 mg single doses in healthy subjects. After the single oral dose, the mean area under the plasma concentration-time curve of oxiracetam in elderly patients was increased by a factor of two as compared to that observed in non-geriatric healthy subjects whereas the maximum concentration (Cmax) was almost not modified and slightly delayed. This can be explained by a slower absorption and elimination in the elderly patients. The highest oxiracetam levels were predominantly recorded in the oldest patients. The slower elimination (mean T1/2 = 12.3 h in elderly and 7.7 h in healthy subjects) could be attributed to a physiological decrease of the renal function. The volume of distribution was not significantly modified in the elderly patients.(ABSTRACT TRUNCATED AT 250 WORDS)