title: The effects of Ginkgo biloba extracts on the pharmacokinetics and pharmacodynamics of donepezil.
abstract: The effects of ginkgo supplementation on the steady-state plasma concentration of donepezil and the activity of cholinesterase in red blood cells and cognitive function were examined. Fourteen inpatients with Alzheimer's disease received donepezil 5 mg/day, supplemented with extracts of Ginkgo biloba 90 mg/day for 30 days. Blood samples were collected before and during ginkgo supplementation and 30 days after its discontinuation, together with an assessment of cognitive function. Plasma drug concentration was measured using high-performance liquid chromatography (HPLC), and cholinesterase in red blood cells was measured using Ellman methods. Cognitive function was evaluated using the Mini-Mental Scale Examination (MMSE). Plasma concentration of donepezil during ginkgo supplementation (mean +/- SD [95% confidence interval]; 24.4 +/- 12.6 ng/mL [17.1-31.7 ng/mL]) was not significantly different from that before ginkgo supplementation (22.7 +/- 10.3 ng/mL [16.8-28.7 ng/mL]) or that 4 weeks after its discontinuation (25.0 +/- 12.9 ng/mL [17.6-32.4 ng/mL]). There was no significant difference between cholinesterase in red blood cells before ginkgo supplementation (1.75 +/- 0.21 U [1.63-1.87 U]), during ginkgo supplementation (1.91 +/- 0.27 U [1.76-2.07 U]), and 4 weeks after its discontinuation (1.83 +/- 0.29 U [1.66-2.00 U]). Ginkgo supplementation did not alter MMSE scores throughout the study. The present study shows that ginkgo supplementation does not have major impact on the pharmacokinetics and pharmacodynamics of donepezil.
authors.affiliation: Department of Clinical Pharmacology, Hirosaki University School of Medicine, Hirosaki 036-8562, Japan.
authors.forename: Norio
authors.initials: N
authors.lastname: Yasui-Furukori
authors.forename: Hanako
authors.initials: H
authors.lastname: Furukori
authors.forename: Ayako
authors.initials: A
authors.lastname: Kaneda
authors.forename: Sunao
authors.initials: S
authors.lastname: Kaneko
authors.forename: Tomonori
authors.initials: T
authors.lastname: Tateishi
mesh_terms: D000284:Administration, Oral; D000368:Aged; D000544:Alzheimer Disease / Q000175:diagnosis / Q000188:drug therapy; D002800:Cholinesterase Inhibitors / Q000097:blood / Q000494:pharmacology / Q000627:therapeutic use; D002802:Cholinesterases / Q000097:blood / Q000737:chemistry; D002851:Chromatography, High Pressure Liquid; D000077265:Donepezil; D004305:Dose-Response Relationship, Drug; D004334:Drug Administration Schedule; D004347:Drug Interactions; D004359:Drug Therapy, Combination; D004912:Erythrocytes / Q000187:drug effects / Q000201:enzymology; D005260:Female; D020441:Ginkgo biloba; D006801:Humans; D007189:Indans / Q000097:blood / Q000494:pharmacology* / Q000627:therapeutic use; D008297:Male; D008609:Mental Status Schedule; D008517:Phytotherapy; D010880:Piperidines / Q000097:blood / Q000494:pharmacology* / Q000627:therapeutic use; D010936:Plant Extracts / Q000008:administration & dosage / Q000737:chemistry / Q000494:pharmacology*; D018515:Plant Leaves / Q000737:chemistry; D010946:Plants, Medicinal / Q000737:chemistry; D013997:Time Factors
chemical_list: D002800:Cholinesterase Inhibitors; D007189:Indans; D010880:Piperidines; D010936:Plant Extracts; D000077265:Donepezil; D002802:Cholinesterases