donepezil
Aricept (donepezil) is an acetylcholinesterase inhibitor originally from Eisai. Taken once daily by mouth, it raises the level of acetylcholine in the brain and is used to treat mild, moderate, and severe dementia of the Alzheimer's type.
This page is based on FDA prescribing information for donepezil, cross-checked with MedlinePlus and the National Cancer Institute dictionary; the mechanism is explained in plain language, and analogies are used only where they stay accurate.
How it works
Explains what the medicine does in the body, not dosing, side effects, or safety.
An analogy
In Alzheimer's disease, the brain cells that release the memory chemical acetylcholine gradually wear out. Donepezil doesn't replace those cells, but it slows the cleanup crew — the enzyme that normally destroys acetylcholine — so more of the chemical lingers at the remaining synapses and the signals can still get through, at least for a while.
In simple terms
Donepezil is a tablet that blocks an enzyme called acetylcholinesterase, which normally breaks down acetylcholine — a chemical the brain uses for memory and thinking. In Alzheimer's disease, the cells that release acetylcholine are damaged, and levels of the chemical fall. By slowing the enzyme, donepezil raises acetylcholine levels at the remaining healthy synapses and can modestly improve or stabilize memory, thinking, and daily function. It does not cure Alzheimer's or stop it from progressing, but it can help symptoms for a time.
In depth
Donepezil is a centrally active, reversible, non-competitive inhibitor of acetylcholinesterase (AChE, EC 3.1.1.7). By binding the catalytic gorge of AChE, it slows hydrolysis of the neurotransmitter acetylcholine, raising synaptic ACh concentrations in cortex and hippocampus and partially compensating for the cholinergic neuron loss characteristic of Alzheimer's disease. Donepezil is highly selective for AChE over butyrylcholinesterase at therapeutic concentrations. It is well absorbed orally, crosses the blood–brain barrier, and is metabolized by CYP2D6 and CYP3A4 with a half-life of approximately 70 hours, supporting once-daily dosing. Clinical efficacy has been demonstrated across mild, moderate, and severe stages of Alzheimer's dementia on cognitive and global clinical endpoints.
See it in motion
A schematic animation of the mechanism — simplified for clarity, not drawn to scale.
Donepezil doesn't replace those cells, but it slows the cleanup crew — the enzyme that normally destroys acetylcholine — so more of the chemical lingers at the remaining synapses and the signals can still get through, at least for a while.
- Donepezil is a tablet that blocks an enzyme called acetylcholinesterase, which normally breaks down acetylcholine — a chemical the brain uses for memory and thinking.
- The enzyme that breaks down the neurotransmitter acetylcholine at synapses; inhibiting it raises acetylcholine levels and partially compensates for the cholinergic neuron loss in Alzheimer's disease.
- By slowing the enzyme, donepezil raises acetylcholine levels at the remaining healthy synapses and can modestly improve or stabilize memory, thinking, and daily function.
- It does not cure Alzheimer's or stop it from progressing, but it can help symptoms for a time.
Target: Acetylcholinesterase (AChE)
The enzyme that breaks down the neurotransmitter acetylcholine at synapses; inhibiting it raises acetylcholine levels and partially compensates for the cholinergic neuron loss in Alzheimer's disease.
Approved uses
Approved uses differ by country and change over time. Always follow your local prescribing information.
Approved uses in United States
FDA- Treatment of dementia of the Alzheimer's type; efficacy has been demonstrated in patients with mild, moderate, and severe Alzheimer's disease
Official sources
The statements on this page trace back to these records.
- U.S. Food and Drug Administration: donepezil prescribing information
U.S. Food and Drug Administration
- MedlinePlus: donepezil
MedlinePlus, U.S. National Library of Medicine
- National Cancer Institute: donepezil hydrochloride
National Cancer Institute
This page explains how the medicine works — it isn’t the patient leaflet. For anything that applies to you, read the leaflet that came with your medicine or ask your pharmacist.
MedUnfold provides educational content and is not medical advice. Always follow your local prescribing information and healthcare professional.