Pharm

Memantine

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Memantine, Namenda, Ebixa, NMDA Receptor Blocker, N-Methyl-D-Aspartate Receptor Blocker, N-Methyl-D-Aspartate Receptor Antagoinst

  • Mechanism
  1. Amantadine derivative with Dopaminergic effects
  • Dosing
  1. Background
    1. Memantine has a long enough half life to be dosed once daily
    2. Memantine regular once daily has equivalent efficacy to Mamantine XR
    3. Memantine regular is generic in 2015 (with brand name discontinued in 2014)
  2. Memantine (Namenda, Ebixa in Europe)
    1. Start: 5 mg orally daily for at least 1 week
    2. Next: 5 mg orally twice daily for at least 1 week
    3. Next: 10 mg orally each AM and 5 mg orally each night for at least 1 week
    4. Next: 10 mg orally twice daily
  3. Memantine ER (Namenda XR)
    1. Start 7 mg orally daily
    2. Titrate daily dose by 7 mg on a weekly basis to maximum of 28 mg daily
      1. Maximum 28 mg/day (14 mg/day in renal Impairment)
  • Indications
  • Moderate to severe Dementia
  1. Consider as alternative to Cholinesterase Inhibitor (e.g. Aricept) if side effects limit use
    1. Memantine may be better tolerated than Cholinesterase Inhibitors
  2. Previously added on to Cholinesterase Inhibitor protocol for added benefit
    1. Combination therapy no longer recommended due to low efficacy (only helped 1 in 12)
    2. Combination therapy is associated with gastrointestinal side effects, Bradycardia and Syncope
  • Efficacy
  1. Can improve cognition and function
  • Pharmacokinetics
  1. Half-life (Memantine): 60-80 hours
  • Adverse Effects
  1. Common adverse effects
    1. Hypertension
    2. Dizziness
    3. Headache
    4. Constipation
    5. Confusion
    6. Vomiting
  2. Rare but serious adverse effects
    1. Cerebrovascular Accident
    2. Acute Kidney Injury
  • References