Aricept (Donepezil), is a centrally acting reversible acetyl cholinesterase inhibitor. Its main therapeutic use is in the treatment of Alzheimer‘s disease where it is used to increase cortical acetylcholine. Donepezil is postulated to exert its therapeutic effect by enhancing cholinergic function. This is accomplished by increasing the concentration of acetylcholine through reversible inhibition of its hydrolysis by acetylcholinesterase. If this proposed mechanism of action is correct, donepezil’s effect may lessen as the disease process advances and fewer cholinergic neurons remain functionally intact.