Advertisement

Treatments are needed that work on many patients, stay effective for a long time, ease a broad range of symptoms, improve patients' cognitive function and ability to carry out activities of daily living, and have no serious side effects. Eventually, scientists hope to develop drugs that attack fundamental AD processes, preventing them from damaging function and quality of life.

The Food and Drug Administration has approved two medications for AD. Both act by inhibiting acetylcholinesterase, an enzyme that normally breaks down acetylcholine, a key neurotransmitter in cognitive functioning. This neurotransmitter is produced by one set of neurons that are lost in AD.

The first of these medications, approved in 1993, was tacrine (Cognex). The second, approved in 1996, was donepezil hydrochloride (Aricept). This drug has less severe side effects than does Cognex and is now commonly used to treat mild to moderate symptoms of AD. However, the drug does not stop or reverse the progression of AD, and it appears to help only some AD patients for a period of time ranging from months to about 2 years, so its usefulness is limited.

The growing understanding of the variety of factors involved in AD's development, including oxidative damage and inflammation, have suggested new potentially fruitful avenues for drug treatment research to modify disease progression or to halt it early on.

The NIA's intramural Baltimore Longitudinal Study of Aging and NIA-supported epidemiologic studies are showing that use of estrogen replacement therapy (ERT) and regular use of some non-steroidal anti-inflammatory drugs (NSAIDs) are associated with lower risks of developing AD.

Scientists caution, however, that individuals should not take these medications just in hopes of preserving cognitive function or reducing the chances of developing AD. Results from epidemiologic studies do not mean a cause-and-effect relationship, and much research still needs to be done in studies involving human AD patients (clinical trials) to determine whether the treatments are safe and effective and to see whether they have a beneficial effect on AD development or progression.