Donepezil, sold under the brand name Aricept among others, is a medication used to treat dementia of the Alzheimer's type.

[3][4][8] Donepezil is a centrally acting reversible acetylcholinesterase inhibitor and structurally unrelated to other anticholinesterase agents.

[8][5] Common side effects include nausea, trouble sleeping, aggression, diarrhea, feeling tired, and muscle cramps.

[15] The UK National Institute for Clinical Excellence (NICE) recommends donepezil as an option in the management of mild to moderate Alzheimer's disease.

[16] In 2006, the U.S. Food and Drug Administration (FDA) also approved donepezil for treatment of mild, moderate and severe dementia in Alzheimer's disease.

[17] In clinical trials the most common adverse events leading to discontinuation were nausea, diarrhea, and vomiting.

[3][5] Donepezil, like other cholinesterase inhibitors, can cause nightmares due to enhanced activation of the visual association cortex during REM sleep.

[3] People with peptic ulcer disease or taking NSAIDs should use with caution because increased risk of gastrointestinal bleeding was noted.

[5] The precise mechanism of action of donepezil in patients with Alzheimer's disease is not fully understood.

[25] {potential activation of somatostatinergic neurotransmission} However, the development was discontinued after Phase II "since the data reviewed did not indicate clear efficacy of the compound for the treatment of mild to moderate Alzheimer's disease.

[38] In a secondary analysis, a subgroup of individuals with the apolipoprotein E4 genotype showed sustained benefits with donepezil throughout the study.

Emerging literature reports that a subset of patients suffering from restrictive anorexia nervosa have enhanced habit formation compared with healthy controls.