Effects of Body Weight on the Safety of High-Dose Donepezil in Alzheimer's Disease: Post hoc Analysis of a Multicenter, Randomized, Open-Label, Parallel Design, Three-Arm Clinical Trial.

Background Donepezil 23 mg is considered for Alzheimer's disease (AD) to optimize cognitive benefits; however, increased adverse events (AEs) can negatively influence drug adherence. We investigated whether body weight (BW) differs based on the presence of AEs, and which baseline factors were relevant to the safety of high-dose donepezil. Methods This study was a post hoc analysis of a multicenter randomized trial between 2014 and 2016. We included patients with moderate to severe AD treated with 10 mg/day of donepezil, and the daily dose was escalated to 23 mg with/without dose titration. Dose titration indicates 15 mg/day of donepezil before escalation or 10 mg and 23 mg/day on alternate days before escalation during the first 4 weeks. The patients were divided into 2 groups based on occurrence of AEs of special interest (AESIs) to compare baseline characteristics. We also assessed relationships between BW and AESIs. Results Among the 160 participants in the safety population, the baseline BWs differed between the AESI (+) (n = 67) and AESI (-) (n = 93) groups. Baseline BW was inversely correlated with the occurrence of AESIs (p = 0.020), and this relationship was prominent in the no-dose titration group (p = 0.009) but absent in the dose-titration groups (p > 0.05). Conclusions BW is the most important factor that correlated with cholinergic AEs. Hence, stepwise dose titration should be considered, particularly in patients with low BW, to minimize the inverse relationship between BW and the occurrence of AEs ("Clinicaltrials.gov" No. NCT02550665 registered on September 15, 2015).