Therapeutic effects of drug switching between acetylcholinesterase inhibitors in patients with Alzheimer's disease

Aim: To evaluate the therapeutic effects of switching from one acetylcholinesterase inhibitor (ChEI), donepezil, galantamine or rivastigmine, to another in Alzheimer's disease patients. Methods: We retrospectively enrolled 171 Alzheimer's disease patients, whose ChEI medication was changed. The patients were evaluated on three major aspects of dementia – cognitive, affective and activities of daily living (ADL) measures – at 6 months (M) before the drug switch, at the time of drug switch (baseline), and at 3 M and 6 M after the drug switch. Results: The doses of the three ChEI were significantly lower at 6 M after the switch compared with the pre-switch doses. Improvements in apathy were found at 3 M when switching from donepezil to galantamine, but not to rivastigmine, but this switch had adverse effects on ADL. Improvements in cognitive scores at 3 M were also found when switching from galantamine to rivastigmine, but not to donepezil. However, both of these changes improved Abe's Behavioral and Psychological Symptoms of Dementia scores (ABS), except ADL. Switching from rivastigmine to donepezil worsened ABS at 6 M, but preserved cognitive and ADL scores. Conclusions: The present study suggests that despite a relatively lower dose of ChEI after the switch, switching from donepezil or rivastigmine preserved cognitive functions for at least 6 M. Switching from galantamine to rivastigmine improved Mini-Mental State Examination and ABS at 3 M, but did not improve ADL scores. Geriatr Gerontol Int 2017; 17: 1843–1848.