Arizil

Arizil Mechanism of Action

donepezil

Manufacturer:

Y.S.P. Industries

Distributor:

Y.S.P. Industries
Full Prescribing Info
Action
Pharmacology: Pharmacodynamics: Donepezil is a piperidine derivative, chemically distinct from the other agents in this class. Donepezil demonstrates relatively high selectivity for central nervous system acetylcholinesterase, with minimal peripheral activity. It reversibly and noncompetitively inhibits centrally-active acetylcholinesterase, the enzyme responsible for hydrolysis of acetylcholine. This is expected to result in increased concentrations of acetylcholine that are available for synaptic transmission. Alzheimer's disease is characterized by cholinergic deficiency in the cortex and basal forebrain, which contributes to cognitive deficits. Donepezil does not alter the course of the underlying dementing process.
Pharmacokinetics: Absorption: Donepezil hydrochloride is well absorbed from the gastrointestinal tract, maximum plasma concentrations being achieved within 3 to 4 hours after ingestion. Food did not affect the absorption of donepezil hydrochloride.
Distribution: It is about 95% bound to human plasma proteins, mainly albumin.
Metabolism: Donepezil is metabolized in the liver. Donepezil undergoes partial metabolism via the cytochrome P450 isoenzyme CYP3A4, and to lesser extent by CYP2D6, to 4 major metabolites. About 11% of a dose is present in plasma as 6-O-desmethyldonepezil, which has similar activity to the parent compound.
Excretion: Over 10 days, about 57% of a dose is recovered from the urine as unchanged drug and metabolites, and about 15% from the faeces; 28% remains unrecovered suggesting accumulation. The elimination half-life is about 70 hours. Steady-state concentrations are achieved within 3 weeks of the start of therapy.
*Sex, race and smoking history have no clinically significant influence on plasma concentrations of donepezil hydrochloride.
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