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How is AD treated?
AD is a complex disease, and no single “magic bullet” is likely to prevent or cure it. That’s why current treatments focus on several different issues, including helping people maintain mental function; managing behavioral symptoms; and slowing, delaying, or preventing AD.
AD research has developed to a point where scientists can look beyond treating symptoms to think about addressing the underlying disease process. Scientists are looking at many possible interventions, such as cardiovascular treatments, antioxidants, immunization therapy, cognitive training, and physical activity.
What drugs are currently available to treat AD?
No treatment has been proven to stop AD. The U.S. Food and Drug Administration has approved four drugs to treat AD. For people with mild or moderate AD, donepezil (Aricept®), rivastigmine (Exelon®), or galantamine (Razadyne®) may help maintain cognitive abilities and help control certain behavioral symptoms for a few months to a few years. Donepezil can be used for severe AD, too. Another drug, memantine (Namenda®), is used to treat moderate to severe AD. However, these drugs don’t change the underlying disease process.
These drugs work by regulating neurotransmitters, the chemicals that transmit messages between neurons. They also may help maintain thinking, memory, and speaking skills and may help with certain behavioral problems.
Other medicines may ease the behavioral symptoms of AD—sleeplessness, agitation, wandering, anxiety, anger, and depression. Treating these symptoms often makes patients more comfortable and makes their care easier for caregivers.
No published study directly compares the four approved AD drugs. Because they work in a similar way, it is not expected that switching from one of these drugs to another will produce significantly different results. However, an AD patient may respond better to one drug than another.
Also see: AD Medications Fact Sheet
What potential new treatments are being researched?
NIA, part of the National Institutes of Health, is the lead Federal agency for AD research. NIA-supported scientists are testing a number of drugs and other interventions to see if they prevent AD, slow the disease, or help reduce symptoms.
Scientists are very interested in the toxic effects of beta-amyloid—a part of amyloid precursor protein found in deposits (plaques) in the brains of people with AD. Studies have moved forward to the point that researchers are carrying out preliminary tests in humans of potential therapies aimed at removing beta-amyloid, halting its formation, or breaking down early forms before they can become harmful. Specific areas of research include immunization with beta-amyloid and beta-amyloid’s disruption of cellular communication.
The aging process
Some age-related changes may make AD damage in the brain worse. Researchers think that inflammation may play a role in AD. Studies suggest that nonsteroidal anti-inflammatory drugs (NSAIDs) might help slow the progression of AD, but clinical trials so far have not shown a benefit from these drugs. Researchers are continuing to look at how NSAIDs might affect the development or progression of AD.
Scientists are also looking at free radicals, which are oxygen or nitrogen molecules that combine easily with other molecules. The production of free radicals can damage nerve cells. The discovery that beta-amyloid generates free radicals in some AD plaques is a potentially significant finding in the quest to understand AD better.
A number of studies suggest that factors such as exercise, a healthy diet, and social engagement may be related to the risk of cognitive decline and AD. For example, studies in older people have shown that higher levels of physical activity or exercise are associated with a reduced risk of dementia.
Scientists have also studied whether certain foods can impact cognitive decline. One study found that mice that ate a diet high in a type of omega-3 fatty acid had reduced beta-amyloid and plaques in brain tissue. The AD Cooperative Study is now testing this fatty acid, DHA, to see if it can slow cognitive and functional decline in people with mild to moderate AD. Also, large-scale clinical trials are studying whether vitamin E and selenium supplements can help prevent memory loss and dementia.
Many studies are looking into other possible treatments. For example, scientists are studying the effects of ginkgo biloba, an extract from a tree, in delaying cognitive decline and treating AD symptoms. Other studies have suggested that estrogen used by women to treat the symptoms of menopause also protects the brain and could reduce the risk of AD or slow the disease.
What are clinical trials?
People who want to help scientists test possible treatments may be able to take part in clinical trials, which are research studies that test the safety, side effects, or effectiveness of a medication or other intervention. Study volunteers help scientists learn abut the brain in healthy aging as well as what happens in AD. Results of AD clinical trials are used to improve prevention and treatment approaches.
NIA sponsors many AD clinical trials, including those conducted by Alzheimer's Disease Centers located throughout the United States. To find out more about clinical trials, talk with your health care provider or contact NIA’s ADEAR Center at 1-800-438-4380. Or, visit the ADEAR Center clinical trials database at AD Clinical Trials Database. Additional clinical trials information is available at www.ClinicalTrials.gov.
Also see: AD Clinical Trials: Questions & Answers
Other questions? Call the ADEAR Center at 1‑800‑438‑4380 or e‑mail our Information Specialists.