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# NMDA receptor antagonists (anti-dementia)

Memantine blocks overactive NMDA glutamate channels. Used in moderate to severe Alzheimer disease; it eases symptoms but does not stop the disease.

Updated 2026-11-01

## What they are

Memantine is the anti-dementia drug of this group. It can be used alone or with a cholinesterase inhibitor such as donepezil. Amantadine, a weaker NMDA antagonist, is filed with the antiparkinson drugs.

## Mechanism of action

Excess glutamate keeps NMDA channels open and may harm neurons. Memantine is a low-to-moderate affinity, uncompetitive (open-channel) blocker: it enters the open pore and leaves quickly, damping the background noise while sparing normal signalling.

Target: NMDA-type glutamate receptor (channel pore)

## Key points

- Indicated for moderate to severe dementia of the Alzheimer type; no evidence that it slows neurodegeneration.
- Cleared by the kidney largely unchanged: dose is adjusted in kidney failure, and alkaline urine raises its levels.
- Combining it with other NMDA antagonists (amantadine, ketamine, dextromethorphan) has not been studied well and calls for caution.

## Drugs in this class

- [**Memantine** An NMDA receptor blocker for moderate to severe Alzheimer disease. It eases symptoms modestly and is cleared by the… NMDA glutamate receptor (channel pore)](https://durgical.com/en/pharmacology/memantine/)

## Test yourself

Think of the answer, then tap the question to see it.

## What kind of NMDA blocker is memantine?

An uncompetitive, open-channel blocker of low to moderate affinity.

## For which stage of Alzheimer disease is memantine indicated?

Moderate to severe dementia.

## Which change in urine raises memantine levels?

Alkaline urine (for example with sodium bicarbonate or carbonic anhydrase inhibitors), which slows its excretion.

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Educational content on how drugs work; not a prescribing guide and no substitute for a health professional's advice. No doses are given.

Sources: [DailyMed - MEMANTINE HYDROCHLORIDE tablet, film coated](https://dailymed.nlm.nih.gov/dailymed/drugInfo.cfm?setid=d0a5e0fc-04e3-417d-bef3-9b309ff71597) (DailyMed (U.S. National Library of Medicine), 2026); [Memantine: MedlinePlus Drug Information](https://medlineplus.gov/druginfo/meds/a604006.html) (MedlinePlus (U.S. National Library of Medicine), 2026); [ATCDDD - ATC/DDD Index](https://atcddd.fhi.no/atc_ddd_index/?code=N06DX) (WHO Collaborating Centre for Drug Statistics Methodology, 2026).

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License: CC BY 4.0 (https://creativecommons.org/licenses/by/4.0/). Cite as: DurgiPedia (durgical.com), https://durgical.com/en/pharmacology/classes/nmda-receptor-antagonists/