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 AD.
AD research has developed to a point where scientists can look beyond treating symptoms to think about delaying or preventing AD by addressing the underlying disease process. Scientists are looking at many possible interventions, such as treatments for heart disease and type 2 diabetes, immunization therapy, cognitive training, changes in diet, 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 stop or reverse AD and appear to help patients only for months to a few years.
These drugs work by regulating neurotransmitters, the chemicals that transmit messages between neurons. They 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.
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. For example, in a clinical trial sponsored by NIA, scientists are testing whether “passive” immunization with an FDA-approved drug called IGIV can successfully treat people with Alzheimer’s.
Some age-related changes may make AD damage in the brain worse. Researchers think that inflammation may play a role in AD. Studies have suggested that common 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 other 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.
Heart disease and diabetes
Research has begun to tease out relationships between AD and vascular diseases, which affect the body’s blood vessels. Some scientists have found that some chronic conditions that affect the vascular system, such as heart disease and diabetes, have been tied to declines in cognitive function or increased AD risk. Several clinical trials are studying whether treatments for these diseases can improve memory and thinking skills in people with AD or mild cognitive impairment.
A number of studies suggest that factors such as a healthy diet, exercise, and social engagement may be related to the risk of cognitive decline and AD. For example, emerging evidence suggests that physical activity might be good for our brains as well as our hearts and waistlines. Some studies in older people have shown that higher levels of physical activity or exercise are associated with a reduced risk of AD. Clinical trials are underway to study the relationship of exercise to healthy brain aging and the development of AD.
Scientists have also studied whether diet may help preserve cognitive function or reduce AD risk. Some studies have found that a “Mediterranean diet” was associated with a reduced risk of AD. To confirm the results, scientists are conducting clinical trials to examine the relationship between specific dietary components and cognitive function and AD.
Studies are looking into many other possible treatments, including hormones and cognitive training, to see if they might improve thinking skills in people with AD or even prevent AD in people who are at risk. For more information about treatment-related research, visit www.nia.nih.gov/Alzheimers or call the ADEAR Center at 1‑800‑438‑4380.
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 in humans. Study volunteers help scientists learn about 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.
National Institute on Aging