Donepezil, marketed under the trade name Aricept, is a medication used in the palliative treatment of Alzheimer's disease. Donepezil is used to improve cognition and behavior of people with Alzheimer's, but does not slow the progression of or cure the disease. Common side effects include loss of appetite, gastrointestinal upset, diarrhea, difficulty sleeping, vomiting, or muscle cramping. It was developed by Eisai and Pfizer and is sold as a generic by multiple suppliers. Donepezil acts as a centrally acting reversible acetylcholinesterase inhibitor.