Cholinergic foundations of Alzheimer's disease therapy.

Cholinesterase inhibitors (ChEI) represent the drug of choice for Alzheimer's disease (AD) treatment. They produce significant improvement on cognitive as well as non-cognitive function for a period up to 1 year during the first 3 years following clinical diagnosis. The magnitude of cognitive improvements is similar for different ChEI, however, differences are seen with regard to incidence and severity of side effects, optimal ChE inhibition, pharmacokinetic properties and mode of administration.