Donepezil is an acetylcholinesterase inhibitor (AChI) that improves cognitive function in Alzheimer's disease (AD) patients. However, AChIs are usually associated with peripheral adverse reactions. Here, we investigated the cardiac outcomes in elderly AD patients treated with donepezil. A total of 82 AD patients (age, 75.47±6.53 years) received 5mg or 10mg donepezil (n=41/group) once daily for 12weeks. Next, we examined the heart rate (HR), cardiac rhythm, and PR, QRS, and QTc intervals. Compared to the 5-mg donepezil-treated group, the HR was slower in the 10-mg donepezil-treated group at the 4th, 8th, and 12th weeks of treatment (p=0.041, 0.026, 0.008, respectively). The PR interval was longer in the 10-mg donepezil-treated group at the 12th week of treatment (p=0.022). Compared to the pretreatment values, the post-treatment HR and PR interval in the 10-mg donepezil-treated group were significantly slower and longer, respectively (p=0.002, p=0.005). Further, the HR was significantly correlated to the donepezil dosage (p=0.014). Similarly, donepezil dosage and treatment interval were significantly correlated (p=0.048). Taken together, our findings suggest that 10mg donepezil decreased the HR of elderly AD patients without inducing severe cardiac outcomes. Therefore, AD patients receiving donepezil should undergo regular cardiovascular monitoring. .