by Soo Borson, M.D.
This question and answer was discussed at the UW Public Forum held on May 17, 2000.
Q. Does Aricept have any side effects?
A. Yes, every drug that is effective can also have adverse side effects. The most common side effects of Aricept and other drugs in the same general class (acetylcholinesterase inhibitors) include nausea, diarrhea, loss of appetite or weight loss, and occasionally urinary incontinence. Most of the time these effects are temporary, and are not usually serious enough to require discontinuation of therapy. Other side effects that can occur at times include nightmares, sleep disruption, or the reverse--increased sleeping. Oftentimes it is possible to avoid side effects, or to treat them when they do occur, by using a lower dose than is usually recommended and working up to the therapeutic dose very slowly. Some people will have to stop taking cholinesterase inhibitors because of side effects, but this is not common. Most people tolerate Aricept very well.
There are some very rare but potentially more serious side effects that can occur. Among the more serious ones is an abnormally slow heart rate, which may cause fainting. This occurs in about 2-5% or less of all people taking Aricept, just slightly above the rates in individuals who take a placebo (inactive agent used in controlled studies of medications). We think that the people who are most vulnerable to this effect are those who already have some interference with cardiac conduction. However, heart disease is not usually a reason to withhold treatment from someone who otherwise might benefit from it.
One important consideration is that other drugs are unlikely to interact with Aricept to cause unwanted side effects. Overall, Aricept is relatively safe, has few side effects, and has been clearly shown to help some individuals with AD. In about 25% of patients, the therapeutic effect is marked; studies show that about 60% benefit significantly in terms of cognition or everyday functioning, although office mental status testing does not always reflect these improvements. Furthermore, in some cases Aricept may improve the effectiveness of other medications used concurrently to treat behavior disturbances or reduce the need for them.