December 10, 2004
The drug Exelon, one of three drugs commonly prescribed for the mild to moderate stages of Alzheimer's disease, may offer modest benefits for those with mental decline due to Parkinson's disease, a new report reveals. The study, the first large and rigorous trial testing an Alzheimer's drug in those with Parkinson's disease, appeared in this week's issue of the New England Journal of Medicine.
Parkinson's disease, which affects some one million Americans, is unrelated to Alzheimer's, but both illnesses can damage the brain and cause loss of memory and other vital mental functions. Symptoms of Parkinson's typically appear around age 50 or 60 and usually consist of problems with movement, such as slowness, rhythmic shaking of the hands, tremors, and stiffness. Eventually, though, confusion, loss of memory, and other symptoms of dementia arise in 40 to 80 percent of cases. For those with Parkinson's and dementia, the downward course of decline in memory and mental functions is similar to that which occurs with Alzheimer's.
This is the first study to show that a medication for Alzheimer's may also help those suffering from dementia due to Parkinson's. Although the study only looked at Exelon (generic name rivastigmine), doctors believe the benefits are likely to apply to the related "cholinesterase inhibitor" drugs used for Alzheimer's, namely Aricept (donepezil) and Reminyl (galantamine). Exelon, however, does affect some brain signals that the other drugs don't.
In the study, the benefit provided by Exelon was similar to that which occurs in people suffering from dementia due to Alzheimer's. The drug improved overall cognition, producing a modest improvement equivalent to about a six-month delay in mental function decline. About one in five of the patients were rated as "meaningfully improved" by health professionals.
Researchers analyzed data from 501 participants, who were an average age of 72. The side effects of the drug were similar to those that occur in people with Alzheimer's, with nausea and vomiting the most common complaints. People with Parkinson's who were taking the Alzheimer's drug also had some increase in tremors, although doctors are not sure if this was a result of the drug.
The findings highlight the importance of research into Alzheimer's causes and treatments, not just for the ravages of Alzheimer's disease but for other serious brain ailments like Parkinson's disease as well. For more on the causes and therapies for Alzheimer's disease and how the Fisher Center for Alzheimer's Research is searching for a cure, visit www.ALZinfo.org.
Emre, Murat, et al:"Rivastigmine for Dementia Associated with Parkinson's Disease." New England Journal of Medicine, Dec. 9, 2004: pages 2509 -- 2518.
Aarsland, Andersen Larsen, et al: "The Rate of Cognitive Decline in Parkinson Disease." Archives of Neurology, Vol. 61, Dec. 2004, pages 1906 -- 1911.