Switching from Oral Cholinesterase Inhibitors to a Transdermal Donepezil Patch Attenuated Gastrointestinal Symptoms and Allowed Treatment Continuation in Three Patients with Alzheimer's Disease in Clinical Settings.

Background: Cholinesterase inhibitors (ChEIs) are commonly prescribed for the treatment of Alzheimer's disease (AD) and achieve long-term benefits for cognition and survival in real-world settings. However, the discontinuation rate is high due to their side effects, with gastrointestinal (GI) symptoms hampering long-term prescriptions. The risk of side effects associated with rivastigmine was previously shown to be lower with transdermal delivery than with oral capsules; however, this has yet to be examined in detail for donepezil, the most widely used ChEI. The daily application of a donepezil transdermal patch was officially approved in Japan in 2023. The incidence of side effects was lower with the donepezil transdermal patch than with oral donepezil in healthy volunteers, but has not yet been assessed in clinical settings. Results: We herein report three AD patients in two different memory clinics who developed GI symptoms with oral ChEIs that were attenuated by switching to the donepezil transdermal patch. Conclusions: The donepezil transdermal patch may improve tolerability and adherence in patients who develop gastrointestinal adverse effects with oral donepezil.