How does memantine work?
Memantine works by blocking the effects of a chemical called glutamate. Glutamate sends messages between nerve cells in the brain.
Nerve cells damaged by Alzheimer's disease make too much glutamate which can cause more damage. Memantine protects nerve cells by blocking the effects of too much glutamate.
How long does it take to work?
Memantine can take up to 3 months to begin working, but this will vary from person to person. You will get a follow-up appointment so your doctor can check how well the medicine is working.
Are there any long-term side effects?
There is no evidence that memantine will harm you if you take it for a long time.
How does memantine compare to other medicines for Alzheimer's disease?
There is another group of medicines for Alzheimer's disease called acetylcholinesterase inhibitors (AChE inhibitors).
AChE inhibitors work in a different way to memantine. AChE inhibitors, such as donepezil, galantamine and rivastigmine, increase levels of acetylcholine, a substance in the brain that helps nerve cells communicate with each other.
AChE inhibitors are used for people with early to mid-stage Alzheimer's disease and may also be continued in the later, severe, stages of the disease. Memantine is not thought to be very effective in mild Alzheimer's disease.
If someone is already taking an AChE inhibitor, taking it with memantine may be a more effective treatment. This may be because they work in different ways. The 2 medicines are safe to take together.
Memantine is prescribed for moderate and severe Alzheimer's disease if you cannot take an AChE inhibitor.
How well does memantine work for dementia?
Memantine does not work for everyone. It is not a cure for dementia and your symptoms may gradually get worse, even when you are taking it.
How each person responds to memantine will be different. Some people find it helps with their symptoms a lot. For others, it might seem like it's not working, but it could be preventing symptoms from getting worse.
It's not thought to help symptoms of mild Alzheimer's disease.
In some people with moderate or severe Alzheimer's disease and other types of dementia, it can help improve a range of symptoms affecting memory and coping with daily life like:
- forgetting recent conversations and where you put things
- forgetting how to do things, like making a cup of tea
- thinking slowly, for example taking longer to reply to what someone says
- finding it more difficult to understand complicated things, like managing money
- delusions or feeling anxious or on edge
- being aggressive, for example lashing out at people or being nasty for no reason
- feeling like you do not want to do things
Can I drive or ride a bike?
Some people feel sleepy or dizzy when taking memantine. If this happens to you, do not drive or ride a bike until you feel OK again.
If you've been diagnosed with dementia, you are legally required to inform the DVLA and your car insurance company promptly.
This does not necessarily mean you have to stop driving immediately. Some people with dementia prefer to give up driving because they find it stressful, but others continue driving for some time as long as it's safe for them to do so.
The DVLA will ask for medical reports and possibly a special driving assessment to decide whether you can continue driving.
Find out more about driving and dementia from the Alzheimer's Society.
Can I drink alcohol while taking memantine?
It's usually best to avoid alcohol, or to cut back on your drinking, when taking memantine.
Drinking alcohol can make the symptoms of dementia worse. It can make you more forgetful or confused.
Is there any food or drink that I need to avoid?
You can eat and drink normally while taking memantine.
However, it's very important to tell your doctor if you have recently changed or intend to change your diet, such as switching to a vegetarian or vegan diet. This can affect the way your kidneys work and cause higher levels of memantine in your blood.
If you do change your diet, your dose may need to be changed.