September 1, 2006
New research shows that popular medications for the treatment of mild to moderate Alzheimer's disease produced similar benefits in easing the symptoms of the memory-robbing ailment. The benefits, however, were modest. And although Alzheimer's drugs may temporarily improve symptoms, none of the currently available medicines do anything to stop the relentless downward progression of disease. In addition, these drugs can produce side effects that in some people are troubling enough that they must stop taking them.
The drugs are known as "cholinesterase inhibitors" because they help modulate a brain enzyme important for memory and thought. All are prescribed for the earlier, mild-to-moderate stages of Alzheimer's disease. They include Aricept (generic name donepezil), Exelon (rivastigmine), and Razadyne (galantamine).
An older cholinesterase inhibitor called Cognex (tacrine) is no longer prescribed because it can cause liver damage. Another Alzheimer's drug, called Namenda (memantine), is prescribed for more serious and severe stages of Alzheimer's and was not examined in the current research.
What the Research Showed
The new research found that the cholinesterase inhibitors Aricept, Exelon, and Razadyne were modestly and similarly effective for the treatment of symptoms of mild to moderate Alzheimer's disease. "Despite the slight variations in the mode of action of the three cholinesterase inhibitors, there is no evidence of any differences between them with respect to efficacy," said study leader Jacqueline Birks, MA, MSc, CStat, from the Cochrane Dementia and Cognitive Improvement Group at Oxford University in England. The findings were presented at the 10th International Conference on Alzheimer's Disease and Related Disorders in Madrid, Spain
The researchers pooled results of 10 different drug trials involving some 7,300 patients. They found that taking these drugs for six months to two years produced modest benefits compared to a dummy pill (placebo). People taking these drugs, on the whole, tended to score better on tests that measure cognitive abilities, including thinking and memory. Doctors also tended to note some improvement in patients taking one of these drugs while examining them.
There was also some evidence that people with mild to moderate Alzheimer's who were taking these drugs could better carry out activities of daily living, such as getting dressed or caring for themselves. There were also fewer problem behaviors, such as aggression. However, none of the treatment benefits were dramatic, and individual treatment results vary from person to person.
As with all drugs, those used to treat Alzheimer's can produce troubling side effects, including digestive upset, nausea, and diarrhea. Side effects caused 29 percent of those taking one of these drugs to stop taking them, compared to 18 percent of people who were taking a placebo. Aricept appeared to produce fewer side effects than the other drugs. If you or someone you care for is taking these drugs, discuss the benefits and drawbacks with your physician.
10th International Conference on Alzheimer's Disease and Related Disorders, Madrid, Spain, July 19, 2006.