Overview
Memantine is an NMDA receptor antagonist used for the treatment of moderate to severe Alzheimer's disease. It works by regulating glutamate activity in the brain to help maintain cognitive function. It is available in various formulations including immediate-release and extended-release tablets.
Mechanism of Action
Memantine is a low to moderate affinity uncompetitive antagonist of NMDA receptors. It binds preferentially to NMDA receptor-operated cation channels, blocking the effects of pathologically elevated tonic levels of glutamate that may lead to neuronal dysfunction.
Indications
- Treatment of moderate to severe dementia of the Alzheimer's type
Common Doses
- 5 mg
- 10 mg
- 7 mg extended-release
- 14 mg extended-release
- 21 mg extended-release
- 28 mg extended-release
Dosage
For immediate-release: Initial dose of 5 mg once daily, titrated weekly to target dose of 10 mg twice daily. For extended-release: Initial dose of 7 mg once daily, titrated weekly to target dose of 28 mg once daily. Dosage adjustments required for renal impairment.
Contraindications
- Hypersensitivity to memantine or any component of the formulation
Side Effects
- Dizziness
- Headache
- Constipation
- Confusion
- Hypertension
- Somnolence
- Hallucinations
- Vomiting
- Fatigue
- Pain
Interactions
- Drugs that alkalinize urine (carbonic anhydrase inhibitors, sodium bicarbonate) may decrease elimination
- NMDA antagonists (amantadine, ketamine, dextromethorphan) may increase risk of adverse effects
- Use with other centrally acting drugs may increase CNS effects
Counseling Points
- Take exactly as prescribed, do not adjust dose without consulting healthcare provider
- Extended-release capsules should be swallowed whole, not chewed or crushed
- Report any new or worsening confusion, hallucinations, or dizziness
- Maintain adequate hydration
- Inform all healthcare providers about all medications being taken