Drug treatments in Alzheimer's
This leaflet is about the drugs used to treat Alzheimer's
disease. It discusses how the drugs work, why they are prescribed,
their side-effects and alternative treatments. Alzheimer's disease
is only one of many possible causes for memory problems in people.
The other causes are described in detail in our leaflet on memory problems and dementia.
What are Cholinesterase inhibitors?
(also known as Acetylcholinesterase Inhibitors)
These are the main drugs used for Alzheimer's disease in the
UK. Three drugs are currently licensed:
|| Other name
There are no major differences between these drugs. They are
all designed to help the symptoms of Alzheimer's disease
- for example, memory loss and anxiety. They are not a cure, though
they may help people to keep their independence for longer.
What effect can these drugs have?
They can improve memory. They can also have general benefits
including improving alertness and motivation. It may take some
months for there to be a noticeable improvement or slowing down of
memory loss. Some people feel brighter in their mood and
will be able to do things that were too hard for them, such as
What side-effects are there?
The most common side-effects are feeling sick, loss of
appetite, tiredness, diarrhoea, muscle cramps and sometimes poor
sleep. These may be reduced or avoided by increasing the dose
slowly, or taking the medicine after food. The side-effects usually
fade after a few weeks and will go away if the medicine is stopped.
More information about side-effects can be obtained from your
doctor or by reading the leaflet that comes with the
How do they work?
Acetylcholine is a chemical that helps pass messages between
certain brain cells involved in memory. In Alzheimer's disease,
these brain cells start to die and the amount of acetylcholine is
very much reduced. Memory starts to suffer. Cholinesterase
Inhibitors reduce the breakdown of acetylcholine and increases its
levels in the brain. This reduces some of the symptoms of
How well do they work?
About 50-60% of people on these drugs show a slight
improvement or a stabilisation of their condition over 6
months. Unfortunately, not everyone benefits from these drugs,
and if no improvement or stabilisation is seen in the first few
months, then they should be stopped.
How should these drugs be taken?
It is usual to start on a low dose which is gradually
increased. Don't be put off by any side-effects early on in the
treatment as these usually wear off after a few weeks. It is
important to take the drugs every day for them to be
How long should these drugs be taken?
These drugs are usually prescribed for a trial period
of 3 to 4 months to see if they show signs of helping. There
is no clear view as to how long they should be taken. If the
condition progresses in spite of treatment, there may come a point
when you and your doctor decide that there is little point in
staying on them.
Who can prescribe these drugs?
A specialist, rather than your GP, will prescribe
the medicine during this trial period. You will usually
see the specialist in a hospital clinic. You may need blood tests
and a brain scan to exclude any other causes for the memory loss.
In some areas, the specialist will continue to prescribe the drug
if they conclude that it is working. In other areas, the GP will
prescribe it after the trial period.
This drug is also known as Ebixa. It is thought to work by
affecting a chemical in the brain called glutamate. In Alzheimer's
disease, too much glutamate leaks out of damaged brain cells and
interferes with learning and memory. In some studies, Memantine was
shown to improve the memory and behaviour of people
with dementia in the medium and later stages. Memantine
can be used for people who find they are intolerant to
The main side-effects of Memantine - which are usually mild -
are nausea, restlessness, stomach ache and headache. This drug is
used in moderate dementia if the cholinesterase inhibitors cause
undue side-effects. It may also help in the more severe stages of
This is a naturally occurring substance extracted from the
Maidenhair tree. It has long been thought to enhance memory.
However, a recent study looked at the effects in Ginkgo in
over 3000 people taking it for an average of 6 years.
Unfortunately, Ginkgo did not stop dementia developing and, in a
small number of people with heart problems, it actually seemed to
make their dementia worse.
Another large analysis of Gingko which included patients
diagnosed with Alzheimer's disease (925 patients from nine trials)
also showed no consistent pattern of benefit
associated with Ginkgo biloba. However, Gingko was
generally considered to be safe.
This is a natural substance found in oils from
soya beans, sunflower seeds, corn and cotton seed, as well as
whole-grain foods, fish-liver oils and nuts. Vitamin E
has many functions in the body. Vitamin E deficiencies are
A recent review of several large studies of Vitamin E found
that it has no benefits in mild cognitive impairment (a noticeable
and measurable decline in cognitive abilities including memory and
thinking skills) or Alzheimer's. Of more concern, the review
also discovered that high doses of Vitamin E may increase the risk
There are lots of drug trials happening all the time to look for
new medications which might help in the treatment of Alzheimer's
disease. Currently, there are trials seeking to find new cognitive
enhancers; these are drugs or supplements that
may improve memory, intelligence, motivation, attention, and
concentration. Other research is seeking to find 'disease
modifying' medications which can alter the course
of Alzheimer's disease to stop its progression.
In the future there will also be more trials of medications to
be used before the disease becomes evident through memory loss.
These are called preventative medications, but they have not yet
been tried in humans.
It may be possible to try some of these newer treatments by
entering into a drug trial. Speak to your GP, a specialist or a
national organisation, such as the Alzheimer's Society, for
- Memory problems and dementia. A
leaflet by the Royal College of Psychiatrists.
- Donepezil, Galantamine,
Rivastigmine (review) and Memantine for the Treatment of
Alzheimer's Disease, National Institute for Health and Care
- Access to drugs:
Alzheimer's Society (2011).
- Ginkgo Biloba - JAMA 2008; 300:2253-62.
- Ginkgo Biloba for cognitive impairment and dementia: Cochrane
- Vitamin E for Alzheimer's disease and Mild Cognitive
Impairment, Cochrane Review 2012.
This leaflet was produced by the Royal College of
Psychiatrists' Public Education Editorial Board.
Series editor: Dr Philip Timms
Expert Review: Dr Thomas Manders and Dr Laura Hill
Last updated: October 2013; Review date: October
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