The symptoms of Alzheimer’s worsen as brain cells die and the connections between cells are lost. At this writing, three drug companies – Eli Lilly, Pfizer and Hoffman la Roche, are preparing to offer monoclonal antibody drugs to make a real difference. These medications have completed third stage trials, and we hop to see them make a big difference soon. Current drugs cannot alter the progressive loss of cells, but they may help minimize or stabilize symptoms. These medications may also delay the need for residential care.
The Alzheimer’s Society has fought to make existing advanced Alzheimer’s drugs available to early and late stage NHS patients. They continue to campaign for drugs to be made freely available to anyone who may benefit from them, and they should probably be your first resource on this subject.
The existing drugs – before monoclonal antibodies and any gene therapies come onstream – can temporarily slow down the progression of Alzheimer’s
symptoms in some people. Aricept, Exelon and Reminyl all work in a similar way and are known as acetylcholinesterase inhibitors. There is also a newer drug, Ebixa, which works in a different way to the other three.
Aricept, Exelon and Reminyl
Research has shown that there is not enough of the chemical ‘acetylcholine’ in the brains of people with Alzheimer’s disease. Acetylcholine is one of the chemicals that nerve cells use to communicate.
Aricept, Exelon and Reminyl prevent an enzyme known as acetylcholinesterase from breaking down acetylcholine in the brain. Increased acetylcholine lead to increased communication between nerve cells, which may in turn temporarily improve or stabilise the symptoms of Alzheimer’s disease.
Aricept, Exelon and Reminyl work in similar ways. However, Reminyl also appears to act on the nicotinic neuronal receptors in the body, making them release more acetylcholine. As well as stopping acetylcholine breaking down, Reminyl can help more of it to be produced. It is possible that one of these drugs might suit an individual better than another.
The action of Ebixa is quite different to, and more complex than, that of Aricept, Exelon and Reminyl. Ebixa blocks a messenger chemical, known as a neurotransmitter glutamate. Glutamate is released in excessive amounts when brain cells are damaged by Alzheimer’s disease, which causes the brain cells to be damaged further. Ebixa can protect brain cells by blocking this release of excess glutamate.
Medline Plus says “US research has suggested that a combination of Aricept and Ebixa is more effective than Aricept alone. Although this research is not conclusive, there is little evidence to support a contrary view. Ebixa works in a completely different way from the acetylcholinesterase inhibitors.” Whether doctors will be allowed to prescribe both drugs together on the NHS, is unclear.
At present Aricept, Exelon and Reminyl are only used in people with mild to moderate Alzheimer’s disease. They are not effective for everyone and may only temporarily improve memory or delay memory loss. Research is ongoing to find out whether any of these drugs may be effective in the later stages of Alzheimer’s disease. Ebixa, however, can temporarily slow down the progression of symptoms in people in the middle and later stages of the disease. This is the first time a drug has been available for this group of people. There is also a suggestion that Ebixa may slow down the disease process itself.
There are side-effects to be considered with all the drugs used for Alzheimer’s. Side-effects of Ebixa include hallucinations, confusion, dizziness, headaches and tiredness. Caution is also recommended for people with epilepsy and heart problems.
Researchers continue to study drugs that may prevent or slow the progression of Alzheimer’s disease. Nonsteroidal anti-inflammatory drugs (NSAIDs), commonly used to treat arthritis, are an example. So is insulin in certain applications. Very exciting progress has been made at the Peninsula School of Medicine on the role of vitamin D3 and fat derived hormones in searching for ways that Alzheimer’s and other dementias may be stopped at an early stage and even reversed. The new monoclonal antibodies develop by Eli Lilly and others have dramatic potential soon.