Valproic acid doses, concentrations, and clearances in elderly nursing home residents

VPA daily dose and total VPA concentrations for 146 elderly (greater than or equal to65 years) nursing home residents collected from June 1998 to December 2000 in homes located throughout the United States are presented. Average age was 78.5 +/- 8.0 years old. The mean VPA daily dose was 16.2 +/- 11.2 mg/kg and mean total VPA concentration was 48.5 +/- 24.8 mg/L. The majority (56.2%) of the VPA residents are being maintained at total VPA levels <50 mg/L. Mean daily dose (19.4 +/- 11.4, 16.3 +/- 112.1, and 11.3 +/- 7.6 mg/kg/day; p = 0.003) and total VPA concentration (56.4 +/- 25.8, 47.7 +/- 22.6, and 38.7 +/- 23.1 mg/kg/day; p = 0.003) decreased by age groups (65-74, 75-84, and greater than or equal to85 years). Daily dose and total VPA concentration were not different in residents receiving inhibitory or inducing co-medications, between men and women, or by albumin level. Total VPA clearance was similar between men and women, among age groups, or according to inducing or inhibiting co-medications. (C) 2004 Elsevier B.V. All rights reserved.