Namenda (Memantine) Indication
Namenda (memantine) is FDA-approved for the treatment of moderate to severe dementia of the Alzheimer's type. 1
Primary Indication
Memantine is specifically indicated for moderate to severe Alzheimer's disease, where it functions as an uncompetitive N-methyl-D-aspartate (NMDA) receptor antagonist. 1
The FDA label clearly states this is the sole approved indication, distinguishing it from cholinesterase inhibitors which are typically used in mild to moderate disease. 1
Clinical Evidence Supporting the Indication
Moderate to Severe Alzheimer's Disease
Memantine demonstrates statistically significant improvements in cognition (measured by Severe Impairment Battery) and global assessment (CIBIC-plus scale) in patients with moderate to severe Alzheimer's disease. 2, 3
The drug shows consistent benefit in this population across multiple domains including quality of life, though the magnitude of cognitive improvement may not always reach the threshold traditionally considered clinically significant (4-point change on ADAS-cog). 4, 5
Meta-analyses confirm statistically significant treatment effects for memantine at 20 mg/day in moderate to severe Alzheimer's disease and vascular dementia populations. 4
Mild to Moderate Alzheimer's Disease (Not FDA-Approved)
Evidence for memantine in mild to moderate Alzheimer's disease is equivocal and this is NOT an FDA-approved indication. 6, 7
Studies in mild to moderate disease show inconsistent results, with memantine failing to demonstrate statistical significance on ADAS-cog scores (P = 0.25). 4
One European trial showed early benefits at 12 and 18 weeks but lost significance at 24 weeks due to unexpectedly high placebo response. 7
Combination Therapy
Memantine can be used as monotherapy or combined with cholinesterase inhibitors (particularly donepezil) in moderate to severe disease. 2, 3
Combination therapy with memantine plus donepezil shows superior outcomes compared to donepezil alone across all four domains: cognition, activities of daily living, global outcome, and behavior. 2, 3
The American Academy of Neurology recommends this combination approach for moderate to severe Alzheimer's disease. 3
Off-Label Considerations
Guidelines suggest memantine may be continued for Parkinson's disease dementia, dementia with Lewy bodies, or vascular dementia, though these are not FDA-approved indications. 2
Memantine should be discontinued for indications other than these specific dementia types. 2