What is Namenda (memantine) used for?

Namenda (Memantine) Usage

Namenda (memantine) is primarily used for the treatment of moderate to severe dementia of the Alzheimer's type. 1

Mechanism and Indications

• Memantine is an N-methyl-D-aspartate (NMDA) receptor antagonist that works by blocking excessive calcium influx caused by chronic overstimulation of the NMDA receptor 2
• FDA-approved specifically for moderate to severe Alzheimer's disease, not mild cases 1
• Available in immediate-release formulations (twice daily dosing) and extended-release (Namenda XR) 28 mg once-daily capsules 3

Clinical Efficacy

• Memantine improves cognition and global assessment in patients with moderate to severe Alzheimer's disease 4, 5
• Studies demonstrate statistically significant improvements on the Severe Impairment Battery (SIB) and CIBIC-plus scale 4
• Benefits have been shown in multiple domains:
  • Cognition (thinking and memory) 4
  • Global function (overall condition) 4
  • Behavior (with less agitation reported in treatment groups) 4
  • Activities of daily living 4

Treatment Approaches

• Can be used as monotherapy or in combination with cholinesterase inhibitors 5
• Combination therapy with memantine plus a cholinesterase inhibitor has shown superior outcomes compared to cholinesterase inhibitor therapy alone 6
• Extended-release formulation (Namenda XR) offers more convenient once-daily dosing that may improve adherence 3

Adverse Effects

• Generally well tolerated with adverse events occurring at similar rates to placebo 7
• Most common adverse events include headache, diarrhea, and dizziness 3
• Withdrawal rates due to adverse effects range from 9-12% in treatment groups 5

Treatment Duration and Discontinuation

• Consider discontinuation if:
  • Clinically meaningful worsening of dementia occurs over 6 months without other contributing factors 5
  • No clinical benefit is observed during treatment 5
  • Patient progresses to severe or end-stage dementia with dependence in most basic activities of daily living 5
• When discontinuing, use a gradual approach, reducing dose by 50% every 4 weeks until reaching the initial starting dose 6

Clinical Considerations

• For patients with neuropsychiatric symptoms (psychosis, agitation, aggression), continue memantine if there has been a clinically meaningful reduction in these symptoms, even with cognitive and functional decline 5
• While memantine shows statistically significant benefits, the magnitude of effect may not reach clinical significance in all domains 4

Cost-Effectiveness

• Modeled analyses indicate memantine is cost-effective compared to no therapy in terms of cost per quality-adjusted life-year (QALY) gained 8
• Treatment has been associated with increased duration of independence and delayed time to institutionalization 8