Medicines for dementia are used to help with symptoms that affect thinking and memory. They are also used to help with symptoms that affect mood and how someone behaves. These medicines do not cure dementia and they may only work for some people. They also may only work for a short time (6-12 months). Medicines for dementia are always started by a doctor who specialises in treating dementia. Like all medicines, they may cause a number of side-effects - for example, diarrhoea, feeling sick (nausea) and being sick (vomiting). But, for most people, any side-effects go away after a few weeks.
What is dementia?
Dementia is a condition of the brain which causes a gradual loss of mental ability. This includes problems with memory, understanding, judgement, thinking and language. In addition, other problems commonly develop, such as changes in personality and changes in the way a person interacts with others in social situations. As dementia progresses, a person's ability to look after themself from day to day may also become affected.
There are several causes of dementia. It can be caused by various diseases or disorders which affect the parts of the brain involved with thought processes. Most cases are caused by Alzheimer's disease. Some of the other types of dementia are:
- Vascular dementia. This is due to problems with the blood vessels in the brain. Brain damage is called by a stroke or a series of tiny mini-strokes.
- Dementia with Lewy bodies (DLB). A type of dementia where abnormal proteins called Lewy bodies are found in the brain.
- Dementia with Parkinson's disease.
- Frontotemporal dementia. A type of dementia where specific parts of the brain only are affected.
- Mixed dementia.
However, sometimes it is not possible to say what has caused dementia.
What are medicines for dementia?
Medicines for dementia are used firstly as a treatment to help with symptoms that affect thinking and memory (cognitive symptoms). Secondly, they are used as treatment to help with symptoms that affect mood and how someone behaves (non-cognitive symptoms). They do not cure dementia.
There are four medicines available in the UK which can be prescribed for dementia. These are donepezil, rivastigmine, galantamine and memantine. They are available as tablets, liquids, tablets that dissolve in water, or patches. They come in various brand names.
In addition, there are a number of other medicines that may be prescribed to people who have dementia. For example:
- An antidepressant may be advised if depression is suspected. Depression is common in people with dementia and may be overlooked.
- Aspirin and other medicines to treat the risk factors for stroke and heart disease may be appropriate for some people. This is especially the case for those with vascular dementia.
- Sleeping tablets are sometimes needed if difficulty sleeping is a persistent problem.
- A tranquilliser or an antipsychotic medicine is sometimes prescribed as a last resort for people with dementia who become easily agitated.
The rest of this leaflet only discusses the use of donepezil, rivastigmine, galantamine and memantine. See the separate leaflet called Memory Loss and Dementia for more details.
How do medicines for dementia work?
Medicines for dementia work by increasing the levels of certain chemicals in the brain.
Donepezil, rivastigmine and galantamine belong to a group of medicines called acetylcholinesterase inhibitors. They work by increasing the level of acetylcholine. This is a chemical in the brain that is low in people with Alzheimer's disease.
Memantine works in a different way to acetylcholinesterase inhibitors. It reduces the amount of a brain chemical called glutamate. It is thought that this may help to slow down the damage to brain cells affected by Alzheimer's disease.
When are medicines for dementia usually prescribed?
Your GP will usually refer you to a doctor who specialises in treating dementia, to confirm that you have dementia. The specialist will then decide if you should have treatment. This decision to start treatment and which treatment to start depends on various things. These include what has caused your dementia, what your symptoms are and how severe your dementia is. Dementia is usually classed as being mild, moderate or severe.
Which medicine for dementia is usually prescribed?
Your specialist will decide which treatment is right for you. There are national guidelines for people with dementia that can help your specialist decide which treatment to choose.
One of the following is usually recommended: donepezil, galantamine and rivastigmine for people with mild or moderate Alzheimer's disease, providing that:
- The medicine is started by a specialist in the care of people with dementia.
- A person receiving treatment has regular reviews and assessments of their condition. (Reviews are usually carried out by a specialist team. Carers' views on the person's condition should also be sought before the medicine is started and should be considered during the reviews.)
Memantine can be considered as a treatment option for:
- People who have moderate Alzheimer's disease and who, for some reason, cannot take, or are intolerant to, the acetylcholinesterase inhibitor medicines.
- People who have severe Alzheimer's disease.
These medicines are not usually used for people with other types of dementia. However, rivastigmine can be used for people with mild-to-moderately severe dementia who also have Parkinson's disease. So, doctors may suggest this medicine for this group of people. Also, an acetylcholinesterase inhibitor medicine may sometimes be suggested for people with DLB who have problems with challenging or disruptive behaviour (non-cognitive symptoms).
How well do medicines for dementia work?
It is thought that about half the people treated with a cholinesterase inhibitor will see an improvement in symptoms that affect thinking and memory. Whether they help with other symptoms such as aggression and agitation has still not been confirmed. The improvement in symptoms is usually only seen for about 6-12 months.
For memantine, some studies have shown that it can slow down the progression of symptoms in some cases.
How should I take these medicines?
It is usual to start with a low dose. This is then increased over a period of weeks to a target treatment dose. The dose is increased slowly because when you first start taking these medicines you may develop some unpleasant side-effects - for example, diarrhoea, feeling sick (nausea) and being sick (vomiting). Most people who develop side-effects find that after a period of time they go away. If you are tolerating a low dose well, your doctor will increase your dose, if needed. How often the dose is increased depends upon which medicine you are taking. For example, if you are taking galantamine, the dose is increased every four weeks. If you are taking rivastigmine tablets, the dose is increased every two weeks. See the leaflet that came with your medicine for more information.
What is the usual length of treatment?
Medicines for dementia are usually only continued for as long as they are thought to be having a worthwhile effect on symptoms.
What about side-effects?
Medicines for dementia cause side-effects in some people. However, if side-effects do occur, they are usually minor and often go away after a few months.
The most common side-effects of anticholinesterase inhibitors include:
- Muscle cramps.
- Feeling tired (fatigue).
- Feeling sick (nausea).
- Being sick (vomiting).
- Not sleeping well (insomnia).
- Being incontinent of urine.
Other less common side-effects include:
- Symptoms of the common cold.
- Loss of appetite.
- Mental health disorders.
- Fainting and seizures.
- A thumping heart (palpitations).
- Flushing or sweating.
Memantine may cause:
- Feeling out of breath.
- High blood pressure.
Other less common side-effects include:
- Blood clots (thrombosis).
- Heart problems.
- Feeling tired.
- Seeing things or hearing things which are not real (hallucinations).
- Problems with walking.
The above is not an exhaustive list but highlights the more common possible side-effects. For a full list of side-effects see the information leaflet that comes with the medicine.
Who cannot take medicines for dementia?
In general, most people are able to take these medicines. Caution may be needed in people with certain medical problems. For example, people with severe liver or kidney problems may not be able to take them, or they may need a lower dose. Care also needs to be taken in people who have had fits in the past.
Can I buy medicines for dementia?
No - you cannot buy medicines for dementia. They are only available on prescription.
How to use the Yellow Card Scheme
If you think you have had a side-effect to one of your medicines you can report this on the Yellow Card Scheme. You can do this online at the following web address: www.mhra.gov.uk/yellowcard.
The Yellow Card Scheme is used to make pharmacists, doctors and nurses aware of any new side-effects that medicines or any other healthcare products may have caused. If you wish to report a side-effect, you will need to provide basic information about:
- The side-effect.
- The name of the medicine which you think caused it.
- The person who had the side-effect.
- Your contact details as the reporter of the side-effect.
It is helpful if you have your medication - and/or the leaflet that came with it - with you while you fill out the report.
Did you find this information useful?
Further help & information
Further reading & references
- Alzheimer's disease - donepezil, galantamine, rivastigmine and memantine; NICE Technology Appraisal Guidance, March 2011
- Dementia; NICE CKS, March 2010 (UK access only)
- British National Formulary; NICE Evidence Services (UK access only)
- Dementia: Supporting people with dementia and their carers in health and social care; NICE Clinical Guideline (November 2006, last updated September 2016)
- Supporting people to live well with dementia; NICE Quality Standard, April 2013
- Dementia; NICE Quality Standard (June 2010)
- Birks J; Cholinesterase inhibitors for Alzheimer's disease. Cochrane Database Syst Rev. 2006 Jan 25 (1):CD005593.
Disclaimer: This article is for information only and should not be used for the diagnosis or treatment of medical conditions. EMIS has used all reasonable care in compiling the information but make no warranty as to its accuracy. Consult a doctor or other health care professional for diagnosis and treatment of medical conditions. For details see our conditions.