Drugs For Alzheimers Disease - Medications For Memory Impairment: Improving Memory Understanding Age Related Memory Loss

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Drugs for Alzheimer's disease

Thus far, no medication has been found to cure Alzheimer's disease or reverse the course of the cognitive and neurological damage it causes. But some drugs seem to temporarily slow the progress of the disease in some people.

Cholinesterase inhibitors. Four medications are available in the United States for treating the symptoms of mild to moderate Alzheimer's: rivastigmine (Exelon), galantamine (formerly Reminyl, renamed Razadyne), donepezil (Aricept), and tacrine (Cognex). All of these drugs are cholinesterase inhibitors. They work by preventing the breakdown of acetylcholine, a neurotransmitter that's important for memory and learning. These drugs are only moderately effective; they might delay the progress of Alzheimer's disease by a number of months, possibly enabling patients to maintain independence for a longer period. Some physicians also prescribe these drugs for mild cognitive impairment.

All four drugs are equally effective in treating the symptoms of Alzheimer's disease. After taking one of them for several weeks, about half of patients are somewhat more alert and better able to care for themselves and engage in activities. The drugs may have other benefits too, according to a report in the Journal of the American Medical Association in 2003. This review of 29 studies found that these drugs might also ease some of the psychiatric symptoms of Alzheimer's, such as depression, anxiety, hallucinations, and delusions.

Where the drugs differ is in convenience of use and severity of side effects. Cognex, the first FDA-approved drug for the treatment of Alzheimer's disease, is rarely prescribed these days because it has the most severe side effects — it can cause liver damage. The side effects of the other drugs are primarily gastrointestinal symptoms, including nausea and diarrhea. Aricept and an extended-release formulation of Razadyne (Razadyne ER) are the most convenient of the drugs because they are taken just once a day, whereas standard Razadyne and Exelon are taken twice a day.

Memantine. Memantine (Namenda) is an NMDA-receptor antagonist, which blocks glutamate, a neurotransmitter, from attaching to NMDA receptors in the brain. Too much glutamate stimulating the receptors can damage neurons and synapses, leading to memory loss and problems with other brain functions. Doctors prescribe memantine alone or in combination with one of the cholinesterase inhibitors for people with moderate to severe Alzheimer's disease, but not for mild cognitive impairment.

Ginkgo biloba. Several small studies have found that an extract from the nuts and leaves of the ginkgo biloba tree is somewhat beneficial to people with Alzheimer's disease. A study published in 2002 suggested a potential mode of action: Ginkgo may help prevent formation of beta-amyloid in the brain, a key pathological feature and possible cause of Alzheimer's. However, other studies have found no beneficial effects.

Gingko biloba

Herbal supplements containing ginkgo are sold over the counter and marketed widely as memory aids, and preliminary research suggests some benefit to healthy people. However, because herbal remedies and supplements are not subject to the same FDA scrutiny as prescription medicines, there's no way to know how the specific content or composition of the product you're buying relates to data published from clinical research trials.

Vitamin E. This vitamin shows some promise for treating Alzheimer's disease. One clinical trial of people with middle-stage Alzheimer's found that taking a very high dose (2,000 IU) of vitamin E slowed the progression of the disease by seven to eight months, a benefit comparable to that of the cholinesterase inhibitors. More research is needed to establish its role in treating Alzheimer's disease.

The news about Vitamin E has not been all positive. A review of previous studies, published in Annals of Medicine in 2005, found that supplements of more than 400 IU marginally increased the risk of death from all causes. However, study sample sizes were small and comprised people with chronic medical illnesses. Additionally, a 2005 study in The New England Journal of Medicine found that vitamin E supplements did not prevent or slow progression of Alzheimer's disease in people with mild cognitive impairment. The National Institute on Aging PREADVISE study (Prevention of Alzheimer's Disease by Vitamin E and Selenium), a large-scale longitudinal study, will provide more definitive information on the potential for vitamin E to prevent the development of Alzheimer's disease in cognitively healthy people.

Statins. If you have high cholesterol as well as a memory disorder, taking one of the class of lipid-lowering medications known as statins might provide a double benefit: lowering your cholesterol level and slowing the progression of memory loss. A study in the Journal of Neurology, Neurosurgery, and Psychiatry in 2005 compared the rate of cognitive decline among people with Alzheimer's disease who were taking statins (for high cholesterol) and people with Alzheimer's who were not taking statins. Those taking statins had a slower rate of decline each year for an average of three years. A large ongoing study called CLASP (Cholesterol Lowering Agent to Slow Progression) is investigating the effectiveness of one of the statins, simvastatin (Zocor), to treat the symptoms of Alzheimer's.

The evidence for statins in the treatment of Alzheimer's disease remains unproven. Although there have been some hopeful findings, doctors do not recommend the use of statins for purposes other than treating high cholesterol. So far, research does not support statins as a preventive measure against Alzheimer's disease.

Last updated:	January 23, 2007