Exelon (rivastigmine) will be available in the UK as a new treatment for Alzheimer’s disease from the end of May 1998. Produced by Novartis Pharmaceuticals, Exelon is not a cure for Alzheimer’s disease. However, it can temporarily ‘slow down’ the progression of symptoms.
The brain is made up of millions of nerve cells, each communicating with each other using chemical messengers called neurotransmitters. One of these neurotransmitters is called acetylcholine. Once acetylcholine has carried out its task of communicating between two nerve cells it is removed by a chemical called acetylcholinesterase.
As Alzheimer’s disease slowly progresses, there is a gradual reduction in the amount of acetylcholine available to be used. This is because the nerve cells in the outer part of the brain and those deep within the brain are continually breaking down. Exelon works by reducing the amount of the acetylcholinesterase, allowing more of the acetylcholine to be available. Drugs which work in this way are referred to as ‘acetylcholinesterase inhibitors’.
Exelon is used for patients with mild to moderate Alzheimer’s disease. It is not effective in every person and will only temporarily improve memory or delay memory loss.
When testing the drug, Novartis included a range of older people who are often excluded from clinical trials, such as those with heart disease or those taking other medications. The patients were therefore more like those typically seen in ordinary GP surgeries and specialist clinics in hospitals. Overall, approximately 3,300 patients took part in the trial. Studies are continuing to see how Exelon works over time.
Exelon is taken twice a day, normally in the morning and evening. People will start with a low dose of 3mg per day and the doctor will increase this to a dose that best suits them, usually of between 6 to 12mg per day. The greatest benefits are often seen on the higher doses so the doctor will probably aim to give a patient as high a dose as possible.
Not everyone suffers the same side effects or has them for the same length of time. The most frequent side effects include mild sickness, headaches, dizziness, stomach pains and sweating. These do not tend to last for very long. However, if they do persist it is important to speak to the doctor. It is also important when starting any new treatment to ask the doctor how the drug may interact with any other medication being taken.
Exelon is only obtainable on prescription through a doctor. This most probably will be a consultant, with subsequent prescriptions issued by the GP. It is important to discuss with the doctor any possible benefits, risks or side effects which might exist. It is impossible to predict the potential benefits from the use of any anti-dementia drug. Some will improve, some will not , while some will continue to deteriorate. The person who is taking the drug must be able to consent to its use.
Aricept (or donepezil hydrochloride), produced by Eisai and co-marketed with Pfizer, was the first drug licensed in the UK for NHS prescription specifically for Alzheimer’s disease. It was launched in April 1997.
Another drug called metrifonate is under development by Bayer, and trials have taken place in the USA, UK, France and Germany. Bayer has applied for a product licence from the European Medicines Control Agency and is hoping that metrifonate will be approved in 1998.
Galanthamine, originally isolated from bulbs of the snowdrop and narcissus, is under development by Shire. Clinical trials are taking place in the USA and Europe.
Soon there will be a number of drugs available for the treatment of Alzheimer’s disease. If a person does not respond to one, they may find another effective. None of these new drugs will cure Alzheimer’s disease or repair damaged brain cells – they will only relieve symptoms.
Researchers are working to develop drugs that are more effective than the acetylcholinesterase inhibitors with fewer side effects.
Propentofylline, a potential neuroprotector, is being developed by a German company called Hoechst and may be used for the treatment of both Alzheimer’s disease and vascular dementia.
Acetyl-L-carnitine (Levacecarnine) is an acetyltransferase stimulant developed by Sigma Tau in Italy for the treatment of Alzheimer’s disease. This drug enhances cell energy production.
Page Text supplied by The Alzheimer's Disease Society of Great Britain