Pharmacotherapeutic Group: Anti-dementia drugs, anticholinesterases. ATC Code: N06DA02.
Pharmacology: Pharmacodynamics: Donepezil hydrochloride is a specific and reversible inhibitor of acetylcholinesterase, the predominant cholinesterase in the brain. Donepezil hydrochloride is in vitro over 1000 times more potent an inhibitor of this enzyme than of butyrylcholinesterase, an enzyme that is present mainly outside the central nervous system.
Pharmacokinetics: Absorption: Donepezil is well absorbed with a relative oral bioavailability of 100% and reaches peak plasma concentrations in 3 to 4 hours.
Distribution: Following multiple-dose administration, steady state is reaches within 15 days. Donepezil is approximately 96% bound to human plasma proteins.
Metabolism: Donepezil is excreted in urine. It is metabolized by CYP-450 enzyme 2D6 and 3A4, and undergoes glucuronidation.
Excretion: The elimination half-life of donepezil is approximately 70 hours and the mean apparent plasma clearance is 0.13 L/h/kg.