Final answer:
None of the drugs listed (Memantine, Donepezil, Rivastigmine, Galantamine) are contraindicated for treating depression in Alzheimer's patients as they are not antidepressants; they are used to improve cognitive function in AD by enhancing acetylcholine neurotransmission.
Step-by-step explanation:
The question pertains to the contraindication of certain drugs in older adult patients with Alzheimer's disease (AD) who also suffer from depression. The medications listed, including Memantine, Donepezil, Rivastigmine, and Galantamine, are primarily used to manage symptoms of AD by targeting the cholinergic system to enhance acetylcholine neurotransmission. These drugs act by inhibiting the enzyme that breaks down acetylcholine, which can improve cognitive function and slow the progression of AD symptoms. It is important to note that antidepressants, not the AD treatments listed, would be the medication class typically considered for treating depression in AD patients. Therefore, none of the options provided (A-D) are directly contraindicated for the treatment of depression in older adults with AD; antidepressant medication would be a separate consideration and could potentially interact with these AD medications.