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memantine (me-man-teen)



Therapeutic: anti-Alzheimer's agents

Pharmacologic: N-methyl-D-aspartate antagonist


Moderate-to-severe Alzheimer's dementia.


Binds to CNS N-methyl-D-aspartate (NMDA) receptor sites, preventing binding of glutamate, an excitatory neurotransmitter. Therapeutic Effects: Decreased symptoms of dementia. Does not slow progression. Cognitive enhancement. Does not cure disease.

Adverse Reactions/Side Effects

CNS: dizziness, fatigue, headache, sedation. CV: hypertension. Derm: rash. GI: weight gain. GU: urinary frequency. Hemat: anemia.


Examination and Evaluation




  • Periodically assess body weight and other anthropometric measures (body mass index, body composition). Report a substantial weight gain or increased body fat.


  • Guard against falls and trauma (hip fractures, head injury, and so forth) caused by drowsiness, dizziness, or other drugs; implement fall prevention strategies (See Appendix E).

  • Help patient and family/caregivers explore nonpharmacologic methods to reduce combative episodes and mood disorders (exercise, structured activities, validation therapies, and so forth).

Patient/Client-Related Instruction

  • Instruct patient and family/caregivers to report other bothersome side effects such as severe or prolonged headache, skin rash, or urinary frequency.


Absorption: Well absorbed after oral administration.

Distribution: Unknown.

Metabolism and Excretion: 57–82% excreted unchanged in urine by active tubular secretion moderated by pH- dependent tubular reabsorption. Remainder metabolized; metabolites are not pharmacologically active.

Half-life: 60–80 hr.

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TIME/ACTION PROFILE (blood levels)

PO unknown 3–7 hr 12 hr


Contraindicated in: Severe renal impairment.

Use Cautiously in: Moderate renal impairment (consider ↓ dose); Concurrent use of other NMDA antagonists (amantadine, rimantadine, ketamine, dextromethorphan); Concurrent use of drugs or diets that cause alkaline urine; Conditions that ↑ urine pH including severe urinary tract infections or renal tubular acidosis (lead to ↓ excretion and ↑ levels); OB/Lactation/Pedi: Safety not established. Discontinue drug or bottle-feed.


Drug-Drug: Medications that ↑ urine pH lead to ↓ excretion and ↑ blood levels (carbonic anhydrase inhibitors, sodium bicarbonate).


PO (Adults): 5 mg once ...

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