Memantine (Namenda)

Class

NMDA receptor antagonist

Mechanism

Noncompetitive antagonist of NMDA-type glutamate receptors, reducing excitotoxicity implicated in neurodegeneration

FDA-Approved Use

Moderate to severe Alzheimer’s disease (AD)

Off-Label Use

Vascular dementia, dementia with Lewy bodies (DLB), post-stroke apathy, catatonia (second-line)

Formulation

Oral tablets, oral solution, extended-release capsules

Titration

Start at 5 mg p.o. daily; titrate weekly as tolerated to 10 mg twice daily (20 mg/day)

Dose Range

5–20 mg/day

Kinetics

Half-life approximately 60–80 hours; primarily renal excretion; dose adjustment required in renal impairment

Common AEs

Dizziness, confusion, headache, constipation, fatigue

Serious/Rare AEs

Rare hypersensitivity reactions

Monitoring

Monitor for tolerability, especially in elderly and medically complex patients; renal function monitoring recommended in severe impairment

Black Box Warning

None

Considerations

May improve cognitive symptoms in AD and vascular dementia. Limited evidence supports use in post-stroke cognitive impairment, Parkinson’s disease dementia, multiple sclerosis (MS), and traumatic brain injury (TBI)-related cognitive decline. Monitor closely for tolerability in elderly and medically complex patients.