What to Expect When Starting Memantine
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Introduction
Memantine (Namenda) is an NMDA receptor antagonist used to treat moderate to severe Alzheimer disease. Unlike cholinesterase inhibitors, memantine works by blocking excessive glutamate activity, which is thought to damage neurons in Alzheimer disease. It is often combined with a cholinesterase inhibitor for additional benefit. The dose is increased gradually over 4 weeks to minimize side effects such as dizziness and confusion.
Week-by-week timeline
Starting at 5 mg
Memantine is started at 5 mg once daily. Side effects at this dose are usually mild: dizziness, headache, constipation, or mild confusion. Some families notice slight improvements in behavior even at this early stage.
Increase to 10 mg Daily
Dose increases to 5 mg twice daily (10 mg total). Mild dizziness may occur with the dose change. Monitor for increased confusion, which is usually temporary.
Increase to 15 mg Daily
Dose increases to 10 mg morning and 5 mg evening. The patient may appear slightly more alert. Side effects typically remain mild.
Target Dose: 20 mg Daily
Full dose of 10 mg twice daily is reached. This is the maintenance dose. Cognitive and behavioral stabilization is the primary goal — improvement is modest in most patients.
Assessing Response
By 8-12 weeks, any benefit from memantine is typically apparent. The medication aims to slow deterioration rather than reverse it. Behavioral symptoms like agitation may be reduced.
Long-Term Management
Memantine is a long-term medication. Regular reassessment of cognitive and functional status is recommended. It is well-tolerated in most patients without the GI side effects of cholinesterase inhibitors.
When to call your doctor
Contact your healthcare provider if you experience:
- Severe confusion or sudden worsening of cognitive function
- Hallucinations or severe agitation not present before starting
- Difficulty walking, falls, or sudden coordination problems
- Signs of urinary tract infection: burning urination, fever, increased confusion in elderly patients
- Seizures
- Chest pain or irregular heartbeat
Tips for getting started
Give memantine at consistent times each day. The extended-release (XR) formulation allows once-daily dosing, which may be easier to manage. Administer with or without food. Set up a medication organizer or phone reminder to avoid missed doses. Caregivers should monitor for any behavioral changes and report them to the prescribing physician promptly.
Frequently asked questions
More about Memantine
References
- [Regulatory] FDA Prescribing Information for Namenda (memantine) https://www.accessdata.fda.gov/drugsatfda_docs/label/2013/021487s009lbl.pdf Accessed 2026-03-01.
- [Regulatory] NIH MedlinePlus: Memantine https://medlineplus.gov/druginfo/meds/a604006.html Accessed 2026-03-01.
- [Clinical] Cochrane Review: Memantine for dementia https://www.cochranelibrary.com/cdsr/doi/10.1002/14651858.CD003154.pub6 Accessed 2026-03-01.
Written and fact-checked by PrescriptionDrugs.org Editorial Team
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