What is the preferred treatment option for an Alzheimer's patient who experienced nausea with oral medication?

Rivastigmine is preferred in this scenario because it is available in a transdermal patch formulation, which can be particularly useful for patients who experience gastrointestinal side effects, such as nausea, when taking oral medications. The transdermal delivery system allows for a steady release of the medication, minimizing fluctuations in drug levels and often resulting in fewer side effects.

While Donepezil and Memantine are also used in the treatment of Alzheimer's disease, they are primarily available in oral formulations, which may not be suitable for this patient due to their previous experience with nausea. Rotigotine is primarily used for Parkinson's disease and is not an appropriate choice for Alzheimer's treatment.

Therefore, Rivastigmine presents a viable alternative for managing cognitive symptoms in Alzheimer's patients who cannot tolerate oral medications due to nausea.