Donepezil. Pharmacoeconomic implications of therapy.

Donepezil is a specific acetylcholinesterase inhibitor that can improve symptoms in patients with mild-to-moderate Alzheimer's disease; cognitive function is maintained above baseline levels for up to 1 year and normal decline of cognitive function is slowed. The ability of the patient to perform daily activities and neuropsychiatric symptoms may also be improved by donepezil, but data are limited. Donepezil is not expected to alter the underlying neurodegenerative process, and the response to the drug varies between individuals. In the absence of validated instruments to measure quality of life, it is not clear how donepezil affects this parameter. In a US survey of caregivers of patients with Alzheimer's disease who were being cared for at home at the start of the 6-month study period, treatment with donepezil did not increase overall direct medical costs. The acquisition cost of the drug was balanced by reduced institutionalisation costs. Economic analyses using Markov models from the US, UK and Canada suggest that donepezil initiated in the early stages of disease may be effectively cost neutral as a result of patients remaining in a nonsevere state of disease for a longer time.