They raise levels of a brain chemical involved in memory. They do not stop the disease, and the benefit is usually measured in months of stability rather than improvement.
Nausea and appetite loss are common side effects. Whether to continue them as dementia advances is a decision worth revisiting with the prescriber.
Why it matters
They are the drugs most families are offered first, and knowing what they can and cannot do prevents disappointment.
Sources
Where to check this, and where to read more. All external and all authoritative.