Alzheimer's Disease

Dementia is an umbrella term used to describe various conditions which damage brain cells and lead to a loss of brain function over time. Dementia causes a progressive decline in a person’s mental functioning. It is a broad term, which describes a loss of memory, intellect, rationality, social skills and normal emotional reactions. The symptoms of dementia develop gradually over a period of years. The progression of these diseases is largely unpredictable for each individual.

Facts in brief
Dementia has a life changing physical, emotional and mental impact on the affected person and their primary carer and family. There are more than 100 conditions that cause dementia. While the risk of dementia increases with age, it is not a natural part of ageing. Dementia affects approximately one in 20 of people aged over 65 years. This rises to one in five in the 80 plus age group. While it is comparatively rare, dementia can affect younger people. There are approximately 3,800 people under the age of 65 with Younger Onset Dementia in the Ireland. A person with dementia will live for an average of four to eight years, depending on their age at diagnosis. Alzheimer's disease, the most common cause of dementia in Ireland, accounts for more than 50% of all cases; the second most common form is vascular dementia, which may be preventable.

Risk Factors

The risk factors for Alzheimer's disease include increasing age being female, family history, head injury, Parkinsons, hypothyroidism, exposure to dietary aluminium, cardiovascular disease, smoking and high alcohol intake

Health maintenance

As Alzheimer’s disease progresses, various conditions develop that may lead to death, such as septicemia, pneumonia and upper respiratory infections, nutritional disorders, pressure sores, fractures, and wounds. In the early stages of Alzheimer’s disease, health maintenance activities should be encouraged including exercise, the control of high blood pressure and other medical conditions, annual immunization against influenza, dental hygiene, and the use of eyeglasses and hearing aids as needed. In later phases of the disease, it is important to address basic requirements such as nutrition, hydration, and skin care.

Diagnosis

There is no straightforward test for Alzheimer’s Disease so diagnosis is difficult, particularly in the early stages. Diagnosis is usually made by excluding other causes such as infection, vitamin deficiency, thyroid problems, brain tumour, depression and the side effects of drugs which all can produce similar symptoms. Diagnosis involves a variety of medical assessments and observations. Assessment usually includes a mini mental state examination (MMSE). Specialists can only make a probable diagnosis. However, clinicians with experience in memory loss are able to diagnose AD to within 80-90% accuracy.

Medication

Medication can slow down progression of AD but is not a cure. Medication should be used in conjunction with non-drug treatment options. For more information on non-drug options, call into Whelehans or discuss with your GP. Four drugs are approved for treatment of dementia in Alzheimer’s Disease (AD) in the UK and Ireland. These are donezepil (ARICEPT^®), galantamine (REMINYL^®), rivastigimine (EXELON^®) and memantine (EBIXA^®). The first three are cholinesterase inhibitors and memantine is a NMDA receptor antagonist. All of these drugs must be started under specialist care. All these drugs now have less expensive but equally effective generic equivalents. These treatments can help improve a person’s memory and enable the person to retain new information for longer. The most common side effects are nausea, vomiting, diarrhoea and anorexia. These can be a particular problem because many people with AD loose weight. However,these side effects wear off after a few weeks in most people. 

Studies have demonstrated modest improvement in cognitive symptoms with cholinesterase inhibitors. Some studies demonstrated a beneficial effect for up to two years after starting treatment. There are no studies of longer periods of medication but most patients can expect that, in time, they will stop responding to treatment as the disease progresses. If the effect wear off, some prescribers recommend a ‘drug holiday’, for example the drug is stopped for six weeks and then started slowly again.

Donepezil has demonstrated in the short term (six months) a beneficial effect on mood and behaviour. Rivastigmine is licensed to treat dementia in Parkinson’s disease. Exelon 4.6mg/24hr transdermal patch and Exelon 9.5mg/ 24hr transdermal patch have been recently launched. The initial dose is 4.6mg/24hr for a minimum of four weeks, and if tolerated, can be increased to 9.6mg/24hr which is considered the recommended effective dose. The rivastigmine patch is considered to have fewer side effects than the capsule version.  Of the four drugs available memantine is the only one licensed to treat moderate severe AD.

There are no guidelines to recommend one drug over another. Donepezil and modified release galantamine only need to be taken once a day which is convenient. Rivastigimine and memantine need to be taken more often though memantine is often given as a single dose in the morning (ie) 2 x 10mg memantine tablets in the morning. There is also insufficient evidence to support the use vitamin E in AD. Further studies are required to test the benefits of Ginkgo biloba.

This article is shortened for this Health Blog. More detailed information and leaflets is available in Whelehans or check www.whelehans.ie

Eamonn Brady is a pharmacist and the owner of Whelehans Pharmacy, Pearse St, Mullingar. If you have any health questions e-mail them to info@whelehans.ie