March 7, 2012 -- The Alzheimer’s drug Aricept helps people with early to moderate signs of the disease maintain a higher level of function, but just how long the drug continues working is not fully understood. A new study may help clear up some confusion.

Aricept is the most widely prescribed medication in a class of Alzheimer’s drugs known as cholinesterase inhibitors. Close to 50% of people stop taking it within a year because of side effects such as weight loss, agitation, and fainting, or because they no longer see any improvements in their mental abilities.

This raises the question of when to stop and what to do next.

Now a new study may provide some much-needed clarity. Aricept can remain effective into the later stages of Alzheimer’s. Adding another drug called Namenda does little to improve these results, even though the combination is common practice.

On its own, however, Namenda may provide some benefits, according to the research. Namenda works on the brain differently than Aricept does. Still, the main goal of this research was to focus more on Aricept’s effectiveness than Namenda’s.

And in the study, those people who stayed on Aricept did better than those who stopped taking it. They scored higher on standard tests measuring their mental ability and also were better able to perform activities of daily living.

These improvements, however, faded in the later stages of  Alzheimer’s.

“The findings are illuminating and this affirms how most of us practice in the U.S.,” says Anton Porsteinsson, MD. He is the William and Sheila KonarProfessor of Psychiatry at the University of Rochester Medical Center in Rochester, N.Y.

“When should we stop?” is a question that comes up often from caregivers and loved ones of people with Alzheimer’s disease who are being treated with Aricept and other Alzheimer’s medicines. “We have this discussion on a regular basis with our patients,” Porsteinsson says.

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Up until now, there was little evidence to support staying on Aricept. “If you stop treatment, they do worse,” he says. ”This substantiates that if someone is doing OK on Aricept and has no side effects, it makes sense to continue.”

And if they do stop Aricept, Namenda is still an option.

“Ongoing treatment matters,” Porsteinsson says.

Does this mean a person with Alzheimer’s will remain independent for longer? It is too soon to say that, Porsteinsson tells WebMD. “What it means is that you stay at a higher level of [mental] function longer. This study didn’t say whether it will keep you out of a nursing home.”
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Peter Davies, PhD, is less enthusiastic about ongoing treatment for Alzheimer’s disease. He is the scientific director of the Litwin-Zucker Center for Research in Alzheimer’s Disease and Memory Disorders at The Feinstein Institute for Medical Research in Manhasset, N.Y.