|Short description Overview   Donepezil is used to treat mild to moderate dementia a conditions known as Alzheimer&rsquos disease. The drug works by improving the function of nerve cells in the brain. It does this by preventing the breakdown of acetylcholine &ndash a chemical in the brain. Acetylcholine is essential in the processes of reasoning, thinking and memory. People suffering from dementia have a low level of this chemical.   It is important to note that Donepezil does not cure Alzheimer&rsquos disease. The disease will progress with time even when using this medicine.   Donepezil may be prescribed for other purposes not mentioned in this guide.