II. Mechanism

  1. Amantadine derivative with Dopaminergic effects

III. 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)

IV. 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

V. Efficacy

  1. Can improve cognition and function

VI. Pharmacokinetics

  1. Half-life (Memantine): 60-80 hours

VII. 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

VIII. References

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Cost: Medications

memantine (on 5/17/2017 at Medicaid.Gov Survey of pharmacy drug pricing)
MEMANTINE 5-10 MG TITRATION PK Generic $0.41 each
MEMANTINE HCL 10 MG TABLET Generic $0.20 each
MEMANTINE HCL 5 MG TABLET Generic $0.19 each
namenda (on 1/1/2017 at Medicaid.Gov Survey of pharmacy drug pricing)
NAMENDA 10 MG TABLET Generic $0.20 each
NAMENDA 2 MG/ML SOLUTION $2.11 per ml
NAMENDA 5 MG TABLET Generic $0.19 each
NAMENDA 5-10 MG TITRATION PK Generic $0.41 each
NAMENDA XR 14 MG CAPSULE $12.43 each
NAMENDA XR 21 MG CAPSULE $12.43 each
NAMENDA XR 28 MG CAPSULE $12.42 each
NAMENDA XR 7 MG CAPSULE $12.39 each
NAMENDA XR TITRATION PACK $12.33 each

Ontology: Memantine (C0025242)

Definition (MSH) AMANTADINE derivative that has some dopaminergic effects. It has been proposed as an antiparkinson agent.
Concepts Pharmacologic Substance (T121) , Organic Chemical (T109)
MSH D008559
SnomedCT 406457005, 406458000
LNC LP100043-1, MTHU035864
English 1,3-Dimethyl-5-aminoadamantane, 1-Amino-3,5-dimethyladamantane, Memantin, Memantine, Tricyclo(3.3.1.13,7)decan-1-amine, 3,5-dimethyl-, DIMETHYLAMINOADAMANTANE 01 03 05, Memantine [Chemical/Ingredient], memantin, memantine, MEMANTINE, Memantine (product), Memantine (substance)
Swedish Memantin
Czech memantin
Finnish Memantiini
Russian MEMANTIN, 1,3-DIMETIL-5-AMINOADAMANTAN, D 145, 1,3-ДИМЕТИЛ-5-АМИНОАДАМАНТАН, МЕМАНТИН
German DIMETHYLAMINOADAMANTAN 01 03 05, 1,3-Dimethyl-5-Aminoadamantan, Memantin
Polish Memantyna
Japanese メマンチン塩酸塩, 1,3-ジメチル-5-アミノアダマンタン, メマンチン, 塩酸メマンチン
Spanish memantina (producto), memantina (sustancia), memantina, 1,3-Dimetil-5-aminoadamantano, Memantina
French Mémantine
Italian Memantina
Portuguese 1,3-Dimetil-5-aminoadamantano, Memantina

Ontology: NMDA receptor antagonist (C0598695)

Concepts Pharmacologic Substance (T121)
SnomedCT 414858002, 406456001
English NMDA receptor antagonist (substance), N-methyl-D-asparate (NMDA) receptor antagonist, N-methyl-D-aspartate (NMDA) receptor antagonist, N-methyl-D-asparate (NMDA) receptor antagonist (substance), NMDA receptor antagonist, n-methyl-D-aspartate receptor antagonist, N-methyl-D-aspartate (NMDA) receptor antagonist (substance), NMDA receptor antagonist (product), N-methyl-D-aspartate receptor antagonist (substance), n-methyl-D-aspartate receptor antagonist (product), N-methyl-D-aspartate receptor antagonist
Spanish antagonista del receptor de N-metil-D-aspartato (producto), antagonista del receptor de N-metil-D-aspartato, antagonista del receptor de NMDA, antagonista del receptor de N-metil-D-aspartato (sustancia)

Ontology: Namenda (C1330412)

Concepts Pharmacologic Substance (T121) , Organic Chemical (T109)
MSH D008559
English Namenda XR, Namenda