A Cochrane review included one study with a total of 15 subjects. Donepezil as compared with placebo produced no significant difference in the duration of delirium developed after elective total joint-replacement surgery. The mean duration of postoperative delirium for the donepezil group was 1.0 day (Standard Error 0.0) while for the placebo group it was 1.3 days (Standard Error 0.19). No other outcomes were measured for the patients who developed delirium.
Comment: The quality of evidence is downgraded by imprecise results (few patients) and by indirectness (relatively young, physically well and cognitively intact patients at low risk of developing delirium).