Memantine use in Alzheimer disease is appropriate for which stage?

• A. Early stage only
• B. Moderate to severe Alzheimer disease
• C. Preclinical stage
• D. All stages equally

Answer: (B)

Memantine works by blocking NMDA receptors to reduce glutamate-related excitotoxicity, which becomes more clinically relevant as Alzheimer disease advances. This mechanism translates into meaningful benefits primarily in moderate to severe stages, where neuronal loss and glutamatergic dysregulation are more pronounced. In this stage, memantine can be used alone or added to a cholinesterase inhibitor to improve cognition and daily functioning. It is not indicated in the preclinical or very early symptomatic phase, where evidence of benefit is lacking, and it isn’t used equally across all stages. Therefore, the appropriate stage for memantine use is moderate to severe Alzheimer disease.