High Doses of Alzheimer’s Drug Should Be Avoided, Advocacy Group Says

August 24, 2011

High doses of the Alzheimer’s drug Aricept should be avoided by some Alzheimer’s patients because of the risk of potentially serious side effects, according to the consumer advocacy group Public Citizen. The drug, also known by its generic name donepezil, is one of the most popular drugs given to ease the symptoms of Alzheimer’s disease.

Aricept comes in several different strengths, the highest being 23 milligrams, which is approved for moderate to severe Alzheimer’s. The group contends that lower doses, like the 10-milligram or 5-milligram doses used to treat mild to moderate Alzheimer’s, can be just as effective for improving memory and attention while posing fewer risks.  This is a generalization and should not be applied uniformly to all patients.  The needs of a given Alzheimer’s patient should be assessed by the patient’s doctor, and it should be decided what dose is best or most effective for an individual patient. 

“Data show that the 23-mg dose of donepezil is significantly more toxic than the 10-mg dose,” which is also approved for moderate to severe Alzheimer’s, said Dr. Sidney Wolfe, director of Public Citizen’s Health Research Group. “Combined with its lack of improved clinical benefits, this leads to only one conclusion: that the 23-mg dose should be immediately withdrawn from the market.”

The group also cautioned consumers against doubling-up doses of the 10-milligram pill. Aricept is normally taken once daily.

Side effects of Aricept include a slowed heart rate, fatigue, dizziness and agitation. Other side effects, like vomiting, which occurred more than three times as often with the 23-milligram dose as the 10-mg dose, can be particularly hazardous to an older person with Alzheimer’s, because it can lead to pneumonia and other problems. Serious bleeding is also a concern.

Some patients who take the drug, even at the lower doses, cannot tolerate the side effects and stop taking it.

The Food and Drug Administration, which reviews evidence for drug safety and effectiveness, approved the higher dose of Aricept. They say that based on studies, the higher doses can be a good choice for certain people with more advanced Alzheimer’s.

All medications have side effects, and it’s important for anyone caring for an Alzheimer’s patient who is taking medications to be aware of them. Often the dose of a drug can be adjusted or an alternative drug can be prescribed, greatly improving a patient’s quality of life.

Common side effects of Aricept include headache, which occurs in about 10 percent of people, insomnia (9 percent), dizziness (8 percent), urinary incontinence (7 percent), muscle cramps (6 percent), digestive upset (5 percent), and nervousness, hostility, confusion, depression or hallucinations (2 to 3 percent). Aricept stays in the system about two weeks, so even after the drug is withdrawn or the dose is lowered, side effects may persist for several weeks.

Aricept belongs to a class of drugs known as cholinesterase inhibitors. Other drugs in that group include Exelon (rivastigmine) and Razadyne (galantamine). Combining these and other drugs may also cause untoward side effects or adverse reactions. 

By ALZinfo.org, The Alzheimer’s Information Site. Reviewed by William J. Netzer, Ph.D., Fisher Center for Alzheimer’s Research Foundation at The Rockefeller University.

Source: Public Citizen Health Research Group, Physicians’ Desk Reference


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