Drug treatments
There is an immense amount of research taking place into new drug treatments for Alzheimer's disease and the other dementias.
Cholinesterase inhibitors
The main compounds used are the cholinesterase inhibitors (also known as anti-cholinesterase drugs). Four have been licensed for use in many countries. These drugs work by reducing the breakdown of acetylcholine in the brain. Acetylcholine is a chemical substance that occurs naturally in the brain and enables nerve cells in the brain to pass messages to each other. Research has shown that many people with Alzheimer's disease have a reduced amount of acetylcholine, and it is thought that the loss of this chemical interferes with memory function.
The cholinesterase inhibitors include donepezil (Aricept®), galantamine (Reminyl® or Razadyne®), and rivastigmine (Exelon®). An earlier drug of this type was tacrine (Cognex®), which has mostly been superseded by the newer compounds because of its significant side effects. Side effects of these drugs may include diarrhoea, nausea, insomnia or vivid dreams, fatigue and loss of appetite.
It is important to realise that these drugs are not a cure, and can only stabilise some of the symptoms of early to mid stage Alzheimer's disease for a limited period of time.
NMDA receptor antagonist
More recently, a different type of drug has become available, which works to modify the function of the NMDA receptor. This is involved with the chemical transmitter glutamate, and research has suggested that too much glutamate is damaging or toxic to the nerve cell. Memantine (known as Ebixa®, Axura® or Namenda®) has been licensed in several countries for treatment of moderate to severe Alzheimer's disease. It is the first drug for people in the later stages of the disease. Although memantine can help with the symptoms, there is no evidence that it modifies the underlying pathology of the disease.
Other drugs
A number of other treatments, including Vitamin E, oestrogen and anti-inflammatory drugs have shown some promising associations, but are not yet proven for routine use. Nootropics, such as Ginkgo Biloba, are available in many countries. Ginkgo seems to improve cerebral blood flow, but consistent improved outcomes with it have not yet been clinically demonstrated.
There is increasing evidence that diet and cholesterol may play a role in the development of the plaques which are characteristic of the pathology in Alzheimer's disease. Research is underway into the use of cholesterol lowering drugs, statins, in the treatment of Alzheimer's disease. Controlled trials of statins are assessing whether the rate of decline in Alzheimer's disease can be modified or slowed by these medications.
Other kinds of drugs are sometimes useful for controlling some of the symptoms of dementia, such as sleeplessness and agitation. In general, however, the use of drugs such as sleeping pills or tranquillisers should be kept to a minimum if someone has dementia, as they can cause increased confusion.
Further information
- Standard Prescriptions for Alzheimer's (Alzheimer's Association USA)
- Alternative Treatments (Alzheimer's Association USA)
- Drug treatments (Alzheimer's Society UK)
- Complementary and alternative medicine and dementia (Alzheimer's Society UK)
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