BACKGROUND: Alzheimer's disease (AD) is characterized by amyloid-β plaques and neurofibrillary tangles. METHODS: We performed a randomized, double-blind, placebo-controlled trial of donepezil in 300 participants with mild cognitive impairment (MCI). RESULTS: Progression to AD occurred in 12% of the donepezil group versus 19% of the placebo group (hazard ratio 0.62; 95% CI, 0.41-0.94). Nausea, diarrhea, and insomnia were more frequent with donepezil. No deaths were attributed to treatment. CONCLUSIONS: Donepezil delayed progression from MCI to AD, although the effect was modest.
