Donepezil Therapy in Alzheimer's Disease

Clinical Efficacy and Dosage

The American College of Physicians recommends starting donepezil 5 mg once daily in the evening, then increasing to 10 mg daily after 4-6 weeks if tolerated, for patients with mild to moderate Alzheimer's disease 1, 2
Donepezil produces a 2.7-point improvement on the 70-point ADAS-Cog scale compared to placebo, in patients with mild to moderate Alzheimer's disease 2
Approximately 20-35% of patients with mild to moderate Alzheimer's disease show a 7-point improvement on neuropsychological tests, equivalent to reversing one year's cognitive decline, when treated with donepezil 1, 2
Clinicians rate global clinical state more positively in treated patients with mild to moderate Alzheimer's disease, with a relative risk of improvement 2.01 on CIBIC-plus scale, when using donepezil 2
Efficacy of donepezil is maintained for up to 4.9 years in patients with mild to moderate Alzheimer's disease 1

For patients with moderate to severe Alzheimer's disease, the American Academy of Neurology recommends initiating donepezil first using the same dosing schedule, then adding memantine after establishing donepezil therapy 1, 2
Combination therapy with memantine shows superior outcomes compared to cholinesterase inhibitor monotherapy, in patients with moderate to severe Alzheimer's disease 1
The combination of donepezil and memantine produces significant benefits on global clinical status, neuropsychiatric symptoms, and reduced caregiver distress, in patients with moderate to severe Alzheimer's disease 3
Adding memantine to stable donepezil therapy provides additional cognitive benefit, with a standardized mean difference 0.36, in patients with moderate to severe Alzheimer's disease 3

The American Geriatrics Society recommends taking donepezil with food to reduce gastrointestinal side effects, such as nausea, vomiting, and diarrhea 1
Donepezil is not hepatotoxic, unlike tacrine, and can be used as a safer alternative 1

The American Academy of Neurology recommends considering stopping donepezil if clinically meaningful worsening occurs over 6 months without other contributing factors, or if no clinical benefit is observed during treatment, in patients with Alzheimer's disease 2, 3
However, donepezil should be continued if there has been a clinically meaningful reduction in neuropsychiatric symptoms, even with cognitive and functional decline, in patients with Alzheimer's disease 3

Donepezil demonstrates statistically significant improvements on ADAS-Cog in patients with vascular dementia, though with a smaller effect size than in Alzheimer's disease 4
Treatment with donepezil does not prevent disease progression, and the illness continues to advance even during treatment, in patients with Alzheimer's disease 2