title: Concentrations of rivastigmine and NAP 226-90 and the cognitive response in Taiwanese Alzheimer's disease patients.
abstract: The aim of this small pilot study was to evaluate the association between plasma concentrations of rivastigmine and its metabolite, NAP 226-90, and cognitive function in patients with Alzheimer's disease (AD). Rivastigmine-treated AD patients, who had been maintained on a fixed regimen of twice daily rivastigmine (6 to 12 mg/d) for ≥6 months, were eligible for evaluation. The assessments included cognitive assessment screening instrument (CASI) and clinical dementia rating scale, conducted at baseline and at 6-month follow-up. The 9 subdomains of CASI at baseline and follow-up were analyzed in relation to the plasma concentrations of rivastigmine and NAP 226-90, as measured by capillary electrophoresis. Logistic regression was performed to adjust for age, gender, education level, apolipoprotein E ε4 genotype status, and baseline CASI score to investigate the association between plasma rivastigmine and NAP 226-90 concentrations and the cognitive response. The total sample consisted of 53 clinically diagnosed AD patients taking rivastigmine only at doses of 6 mg to 9 mg/d because of intolerability at 12 mg/d. Higher rivastigmine concentration was significantly associated with improved or preserved short-term memory and worsened abstraction/judgment (p < 0.05), but not with changes in other domains (p > 0.05). Higher NAP 226-90 concentration was significantly associated with worsened abstraction/judgment (p < 0.05), but not with changes in other domains. Higher plasma rivastigmine concentration was significantly associated with improved or preserved short-term memory but worsened abstraction/judgment. An optimal concentration of rivastigmine should be quantified for each patient because of differential cognitive responses.
authors: Department of Neurology, Kaohsiung Municipal Ta-Tung Hospital, Kaohsiung, Taiwan.
authors: Mei-Chuan
authors: MC
authors: Chou
authors: Chun-Hung
authors: CH
authors: Chen
authors: Ching-Kuan
authors: CK
authors: Liu
authors: Su-Hwei
authors: SH
authors: Chen
authors: Shyh-Jong
authors: SJ
authors: Wu
authors: Yuan-Han
authors: YH
authors: Yang
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D000544:Alzheimer Disease / Q000188:drug therapy / Q000453:epidemiology*; D003072:Cognition Disorders / Q000188:drug therapy / Q000453:epidemiology*; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D008297:Male; D010627:Phenethylamines / Q000627:therapeutic use*; D010636:Phenols / Q000627:therapeutic use*; D048448:Phenylcarbamates / Q000627:therapeutic use*; D010865:Pilot Projects; D000068836:Rivastigmine; D013624:Taiwan / Q000453:epidemiology
chemical_list: C494046:3-(1-dimethylaminoethyl)phenol; D010627:Phenethylamines; D010636:Phenols; D048448:Phenylcarbamates; D000068836:Rivastigmine