Background: Donepezil is a first-line drug for the treatment of Alzheimer's disease (AD). However, there are no meta-analyses on efficacy and safety of high-dose versus standard-dose donepezil in the treatment of moderate-to-severe AD.

Research design and methods: We searched for randomized controlled trials (RCTs) from 1993 to May 2021 PubMed, Cochrane Library, EMBASE, Web of Science, and Scopus databases. The outcomes of the meta-analysis included cognitive function, global assessment, and the incidence of adverse events and serious adverse events.

Results: Five RCTs (2974 people) were included in this meta-analysis. The improvement of cognitive function was significant among the patients with the treatment of high-dose donepezil [SMD = 0.12, 95% CI: 0.03 ~ 0.22; p = 0.01]. Between the two groups, there was no significant difference in global assessment. Compared with standard-dose donepezil, there was no difference in the incidence of adverse events when high-dose donepezil was used. However, it was found that high-dose donepezil administration increased the risk of heart problems through subgroup analysis of the two serious adverse events.

Conclusion: High-dose donepezil is more effective than standard-dose donepezil in improving cognitive function of the elderly with moderate-to-severe AD. However, more attention should be paid to patients with heart problems when high-dose donepezil was used.