Memantine is used in moderate to severe Alzheimer's disease. Its mechanism of action is:
- A Acetylcholinesterase inhibition, increasing synaptic acetylcholine
- B Uncompetitive NMDA receptor antagonist, reducing glutamate excitotoxicity ✓
- C Muscarinic M1 receptor agonist
- D Beta-amyloid aggregation inhibitor
Correct answer: B. Uncompetitive NMDA receptor antagonist, reducing glutamate excitotoxicity
Explanation
Memantine is an uncompetitive, low-affinity NMDA receptor antagonist that blocks tonically active, pathological NMDA receptor activation (glutamate excitotoxicity) while sparing physiological synaptic transmission required for learning and memory. It is approved for moderate-severe AD (MMSE 3-14). Cholinesterase inhibitors (donepezil, rivastigmine, galantamine) inhibit AChE. They can be combined — donepezil + memantine is standard for moderate-severe AD.
Reference: Kaplan & Sadock's Synopsis of Psychiatry, 11th ed.
High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP
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