Memantine (Namenda) for Alzheimer's Disease
Also known as: Namenda, Namzaric (combination)
The only NMDA receptor antagonist approved for Alzheimer's, targeting glutamate excitotoxicity in moderate-to-severe disease.
Mechanism of Action
Memantine is a low-to-moderate affinity, uncompetitive NMDA receptor antagonist that blocks pathological tonic glutamate signaling while preserving physiological phasic signaling needed for learning and memory. This 'neuroprotective' mechanism reduces excitotoxic calcium influx without completely blocking NMDA receptor function.
General mechanism: Uncompetitive NMDA receptor antagonist. Blocks pathological tonic glutamate signaling while preserving physiological phasic signaling.
Current Evidence
Clinical trials show modest cognitive and functional benefit in moderate-to-severe Alzheimer's. Combination with donepezil (Namzaric) provides additive effects. Well-established safety profile. Does not slow disease progression.
Clinical Status: FDA-approved for moderate-to-severe Alzheimer's (2003). Generic available. Standard of care in combination with cholinesterase inhibitors.
Safety Profile
Well-tolerated. Dizziness, headache, and constipation are common. Fewer GI effects than cholinesterase inhibitors.
Key Research Questions
- Can memantine be combined with anti-amyloid antibodies for synergistic benefit?
- Does memantine's neuroprotective mechanism provide value in early disease stages?
- What role does glutamate excitotoxicity play relative to amyloid and tau pathology?