Increased dosage of donepezil for the management of behavioural and psychological symptoms of dementia in dementia with Lewy bodies

Background: As with other types of dementia, the behavioral and psychological symptoms of dementia (BPSD) can make caregiving difficult for patients with dementia with Lewy bodies (DLB). We hypothesized that administration of donepezil at an increased dose of 10 mg/day might dose-dependently improve BPSD in DLB patients with relapse, after their symptoms had been controlled initially by donepezil therapy at the standard dose. Methods: The present study was as an open-label trial. We enrolled 24 patients with DLB (diagnosed according to the Consortium on Dementia with Lewy Bodies Guideline-Revised) who experienced a relapse of BPSD despite treatment with donepezil at the standard dose (5 mg/day). The donepezil dose for these patients was increased to 10 mg/day, and we evaluated the efficacy and safety of this dose escalation strategy. Results: The Neuropsychiatric Inventory (NPI) scores for BPSD showed statistically significant improvements as a result of the increased dosage, except those for anxiety and euphoria, disinhibition, irritability/lability. High-dose donepezil therapy caused gastrointestinal symptoms in 4 patients, but there were no life-threatening adverse events, such as arrhythmias, or no exacerbation of parkinsonian symptoms. Conclusions: We found that donepezil dose-dependently improved relapsing BPSD in these patients. Therefore, increasing the dosage of donepezil is a safe and effective treatment for patients with DLB who experience a relapse of BPSD.