Which medication is a glutamate receptor antagonist that may benefit a patient with severe Alzheimer disease symptoms?

Memantine is indeed a glutamate receptor antagonist and is used to manage moderate to severe symptoms of Alzheimer's disease. It works by blocking the activity of glutamate at the NMDA (N-methyl-D-aspartate) receptors. In Alzheimer's disease, excessive glutamate activity can lead to neuronal toxicity and contribute to the cognitive decline seen in patients. By acting as an antagonist, memantine helps to regulate glutamate levels, thus providing neuroprotective effects and helping to improve cognitive function and daily living activities for those suffering from advanced Alzheimer’s disease.

Other medications listed in the choices primarily function as cholinesterase inhibitors (such as rivastigmine and galantamine) or as dopamine agonists (like pramipexole), and they do not target the glutamate receptor pathway. Cholinesterase inhibitors increase levels of acetylcholine, which can help with symptom management but does not specifically address the glutamate-mediated excitotoxicity that may occur in Alzheimer's disease. Therefore, memantine stands out as the appropriate treatment option for the particular need addressed in the question.