In a patient recently diagnosed with Parkinson's disease dementia, which medication is most likely to be prescribed?

• A. Rivastigmine
• B. Donepezil
• C. Galantamine
• D. Memantine

Answer: (A)

Parkinson's disease dementia involves a loss of cholinergic neurons, leading to cognitive decline and difficulties with daily function. To help with these symptoms, medicines that increase acetylcholine in the brain are used. Rivastigmine is particularly suitable here because it inhibits both acetylcholinesterase and butyrylcholinesterase, addressing a broader cholinergic deficit seen in Parkinson’s-related dementia. It has specific approval for Parkinson’s disease dementia and has shown in trials to produce modest but meaningful improvements in cognition and daily activities. Starting at a low dose and titrating helps limit side effects such as nausea and weight loss, and using the patch can further reduce GI issues. Other agents like donepezil and galantamine are approved mainly for Alzheimer's disease, and memantine is not the first choice for Parkinson’s dementia due to limited supporting evidence in this condition. Thus, rivastigmine is the best fit for treating Parkinson’s disease dementia in this scenario.