Cholinesterase inhibitors

Cholinesterase inhibitors block the enzyme that breaks down acetylcholine, a chemical messenger involved in memory and thinking. Donepezil, rivastigmine, and galantamine treat the symptoms of Alzheimer disease dementia but do not stop the disease from progressing. Nausea, vomiting, diarrhea, loss of appetite, and trouble sleeping are common. The extra acetylcholine can slow the heart rate and cause fainting, and it can increase stomach acid, raising the risk of stomach bleeding.

• DonepezilKnown brand names include Aricept.