A medicine for moderate-to-severe Alzheimer’s dementia
Memantine
A dementia medicine used in moderate-to-severe Alzheimer’s disease — it does not cure or stop the illness, but can help with symptoms and daily function, and is generally well tolerated.
What is Memantine?
Memantine is used for moderate-to-severe Alzheimer’s disease, either on its own or alongside a different type of dementia medicine. It works differently from the common Alzheimer’s drugs by calming excess activity of a brain chemical (glutamate). It does not cure or reverse dementia, but it can modestly help symptoms, behaviour and everyday function, and it is usually well tolerated.
Education and reference only. This is a plain-language guide to Memantine — it deliberately contains no doses. Doses depend on the person, the brand and the reason for treatment, and belong with your prescriber. Always check the BNF, the product labelling (SmPC) and follow medical advice.
What it is
Memantine is one of the main medicines for Alzheimer’s disease, used in the moderate-to-severe stages (whereas the "cholinesterase inhibitors" such as donepezil are used from the mild stage). It can be taken on its own or combined with one of those medicines. Like all current dementia medicines, it treats symptoms rather than the underlying disease — it does not stop Alzheimer’s progressing — but it can help maintain memory, thinking, behaviour and the ability to manage daily activities for a time. It is taken as a once-daily tablet or liquid.
How it works
In Alzheimer’s disease, nerve cells can be over-stimulated by a brain chemical called glutamate acting on NMDA receptors, and this excess activity is thought to contribute to nerve-cell damage and to interfere with the signals involved in memory and learning. Memantine gently blocks these NMDA receptors, dampening the harmful over-activity while still allowing normal signalling — which can help protect function and ease some symptoms.
What it treats
Conditions Memantine is used for
Practical use
How to take Memantine
General, dose-free guidance — always follow your prescriber's and the leaflet's specific instructions.
- Take it once a day, with or without food; when starting, the amount is usually increased gradually over a few weeks.
- Keep a consistent routine — a carer or reminder system can help ensure it is taken regularly.
- Report significant dizziness, confusion or drowsiness, especially when the dose is being increased.
- Tell the prescriber about kidney problems, as the amount may need reducing.
- Continue it as advised; its benefit is reviewed periodically rather than stopped abruptly.
Weighing it up
Advantages & disadvantages of Memantine
Advantages
- Can modestly help symptoms and daily function in moderate-to-severe Alzheimer’s.
- Generally well tolerated, with fewer digestive side effects than cholinesterase inhibitors.
- Can be combined with a cholinesterase inhibitor, and taken once daily.
Disadvantages
- Does not cure or stop Alzheimer’s disease — benefit is modest and symptomatic.
- Can cause dizziness, headache or confusion, especially early.
- Needs a reduced amount in significant kidney impairment.
Practical use
Good to know
It is important to have realistic expectations: memantine does not cure Alzheimer’s or halt its progression, but it can provide a modest benefit for symptoms and daily function, and it may help with agitation or distress in some people. It is generally well tolerated, with fewer digestive side effects than the cholinesterase-inhibitor drugs, and it is usually built up gradually to reduce side effects such as dizziness. The amount is reduced in significant kidney impairment because it is cleared by the kidneys. Benefit is reviewed over time, and the medicine is continued while it is judged to be helping.
Who should not take it / use with caution
- People with a known sensitivity to it.
- Used at a reduced amount and with care in significant kidney impairment, epilepsy, and some heart conditions.
- Pregnancy and breastfeeding — generally avoided unless specifically advised.
Monitoring
- Cognition, behaviour and daily function (benefit review)
- Kidney function (guides the amount)
- Side effects during dose increases
Side effects
- Common: dizziness, headache, drowsiness, constipation and raised blood pressure.
- Sometimes confusion, hallucinations, or unsteadiness — report these.
- Generally milder on the stomach than the cholinesterase-inhibitor dementia drugs.
Key interactions
- Other medicines acting on the same brain pathway (such as amantadine, ketamine) are avoided together.
- Medicines that make the urine more alkaline can raise memantine levels.
- Care alongside some Parkinson’s and antispasm medicines, and other sedating drugs.
Available as: Tablets and an oral liquid (solution); a combined tablet with a cholinesterase inhibitor exists in some settings.
Answers
Memantine: frequently asked questions
Will memantine cure or stop my dementia?
No — like all current dementia medicines, memantine treats symptoms rather than the disease itself, so it does not cure Alzheimer’s or halt its progression. What it can do is provide a modest benefit for memory, thinking, behaviour and daily function for a period, which can be meaningful for the person and their carers.
How is memantine different from donepezil?
They work in different ways and are used at different stages. Cholinesterase inhibitors like donepezil are used from mild Alzheimer’s and boost a different brain chemical; memantine is used in moderate-to-severe disease and calms excess glutamate activity. The two can sometimes be used together. Memantine also tends to cause fewer digestive side effects.
Is memantine well tolerated?
Generally yes — it is usually well tolerated, especially compared with the cholinesterase inhibitors, and starting it gradually helps reduce early effects like dizziness. Report significant dizziness, confusion or drowsiness, particularly while the dose is being built up.
What if the person has kidney problems?
Memantine is removed by the kidneys, so in significant kidney impairment the amount is reduced to avoid it building up. Make sure the prescriber knows about any kidney problems so the dose can be set safely.
Authoritative sources
- BNF: Memantine hydrochloride.
- electronic Medicines Compendium (SmPC): Memantine (Ebixa).
- NICE NG97: Dementia – assessment, management and support.
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