Memantine is used to treat moderate to severe Alzheimer's disease. It acts on the glutamatergic system by blocking NMDA receptors.

  • Memantine is indicated for the treatment of patients with moderate to severe AD (i.e. - the MMSE score must be < 20).[1]
  • Glutamate is the main excitatory neurotransmitter in the brain, and binds to the NMDA receptor in the brain.
    • Excessive glutamate release leads to excitotoxicity, which is thought to be a major mechanism of neurodegeneration in ischemia from stroke, trauma from traumatic brain injuries, and neurodegenerative disorders.
    • However, glutamatergic transmission also important for long-term potentiation, and this is a proposed cellular model for learning and memory
  • Memantine is a non-competitive NMDA receptor antagonist that is thought to help prevent excitotoxicity (mediated by Ca2+)
  • Memantine blocks NMDA receptors and so may reduce the negative effects of glutamate, namely the excitotoxicity pathway via NMDA receptor over-activation, which is thought to prevent cell death.
  • Memantine may also be neuroprotective.
  • Week 1: 5 mg PO qAM
  • Week 2: 5 mg PO BID
  • Week 3: 10 mg PO qAM and 5mg PO qHS
  • Week 4: 10 mg PO BID
  • Dose should be halved in patients with renal impairment.[2]
  • Use with caution in patients with severe hepatic or renal impairment
  • Memantine is generally well tolerated. Most common side effects may include insomnia, diarrhea, urinary incontinence, confusion, dizziness, or agitation.
  • Memantine though not as effective, is much better tolerated than acetylcholinesterase inhibitors
  • No major drug interactions.