Monday, February 13, 2006

Alzheimer's disease treatment

Your specific treatment for Alzheimer's disease will be determined by your doctor based on:
Your age, overall health, and medical history
Extent of the disease
Your tolerance for specific medicines, procedures, and therapies
Expectations for the course of the diseas
Your opinion or preference
At this time, there is no cure for Alzheimer's disease, there is no way of slowing the progression of the disease, and there is no treatment available to reverse its effects. But medicines can help patients with Alzheimer's disease.
In general, healthy lifestyle changes that protect the body from strokes and heart attacks tend to protect the brain from cognitive decline. Older adults who exercise, maintain their normal body weight, avoid head trauma, have no more than one standard alcoholic beverage daily, and stay socially engaged maintain their cognitive abilities best. These recommendations are appropriate at all stages of disease but need to be tailored to the individual's preferences and abilities.
Adults in early stages could attend courses at a local community college, take classes at a senior center, or participate in library book clubs. Those with moderate or severe disease may benefit from organized activities in an adult day-care setting. Also, treatment of hypertension is important in protecting the brain against cognitive decline, as are prevention and treatment of diabetes with exercise and medications.
Researchers continue to study drugs and other substances as possible treatments for Alzheimer's disease. Carefully designed and conducted studies are necessary to give a clear picture of safety and effectiveness before any approval may be considered. In addition, clinical trials are being conducted on a vaccine to prevent and possibly reverse plaque formation.
Treating mild-to-moderate disease
For now, there is no cure for Alzheimer's disease, there is no way of slowing the progression of the disease, and there is no treatment available to reverse its effects. But medicines known as cholinesterase inhibitors can help patients with mild and moderately severe Alzheimer's disease.
Cholinesterase inhibitors block the action of acetylcholinesterase, the enzyme responsible for the destruction of acetylcholine, a chemical that helps nerve cells in the brain transmit impulses. Reduced levels of acetylcholine in the brain are believed to be responsible for some of the symptoms of Alzheimer's disease. By blocking the enzyme that destroys acetylcholine, these medications increase the concentration of acetylcholine in the brain. This increase is believed to be responsible for the improvement in memory and cognition seen with these medications.
Cholinesterase inhibitors include:
Tacrine (Cognex): Side effects of tacrine include nausea, vomiting, diarrhea, abdominal pain, skin rash, and indigestion. In addition, tacrine can damage the liver, so regular monitoring is necessary. Tacrine is rarely prescribed now because of the liver side effects.
Donepezil (Aricept): Donepezil is the drug most widely used for Alzheimer's disease. Donepezil has fewer and milder side effects than tacrine. Side effects include diarrhea, vomiting, nausea, fatigue, insomnia, and anorexia. Like tacrine, Donepezil does not cure Alzheimer's or slow its progression.
Rivastigmine (Exelon) or galantamine (Razadyne): These newer drugs also work by inhibiting the breakdown of acetylcholine and are similar in benefits and side effects.
In all cases, the drugs seem to primarily help those with mild or moderate symptoms of Alzheimer's disease. The improvement is modest, and the drugs do not halt progression of the disease. These improvements may help reduce caregiver burden, delay nursing home placement, and improve neuropsychiatric problems (such as apathy and agitation). There is some evidence that these benefits may be sustained with treatment of more advanced disease.
Treating moderate to severe disease
Memantine (Namenda) is approved by the FDA for treatment of moderate-to-severe Alzheimer's disease. It blocks the neurotransmitter glutamate from activating special receptors on nerve cells, keeping the cells healthier. Memantine is the first drug to be approved for moderate-to-severe dementia; the cholinesterase inhibitors currently are approved only for mild-to-moderate symptoms.
Clinical studies have found that patients with moderate-to-severe Alzheimer's disease who took memantine performed better on scales measuring the common activities of daily living such as eating, walking, using the toilet, bathing, and dressing as compared with patients on placebo. The lower-functioning patients may benefit the most.
Memantine appears to be safe and effective alone or when used together with a cholinesterase inhibitor. However, as with the cholinesterase inhibitors, the effect on cognition and abilities is modest and may decline after about six months. Research is ongoing to determine long-term benefits.
Memantine is thought to play a protective role in the brain by regulating a chemical messenger called glutamate. Glutamate plays a key role in learning and memory by acting as a kind of "gatekeeper" of some of the brain's other chemicals--allowing certain amounts of these other chemicals (such as calcium, which is required for information storage) to enter the brain's nerve cells. Allowing too much calcium into the nerve cells can damage and destroy them. Memantine keeps the glutamate under better control, which keeps the calcium under better control, which helps keep the brain's nerve cells functioning more normally.
Very few side effects have been reported by patients taking memantine. From the clinical trials, the most commonly reported side effects--and those that were reported at a frequency 2 percent or more than placebo recipients--include dizziness, headache, and constipation.
Other medications and dietary supplements
Vitamin E: Vitamin E, an antioxidant, may be modestly effective in slowing progression in some patients with dementia. One study demonstrated benefit of vitamin E in high doses (1,000 international units twice daily) in people with moderate dementia. The use of vitamin E delayed the time to death, institutionalization, loss of the ability to perform basic activities of daily living, or severe dementia. Other studies have shown little or no benefit, and high doses of the vitamin may have adverse effects on cardiovascular health.
Ginkgo: Ginkgo biloba, an extract from the leaves of the ginkgo tree, has been touted by many as a memory enhancer. Although a 1997 study suggested that a ginkgo extract may be of some value in treating the symptoms of Alzheimer's disease and other forms of dementia, there is no evidence that ginkgo biloba will cure or prevent Alzheimer's disease. Other studies, however, imply that daily use of ginkgo biloba may cause side effects, such as excessive bleeding (especially when combined with daily use of aspirin). To date, there simply is not enough information available for doctors to recommend the broad use of ginkgo biloba for Alzheimer's disease or other forms of dementia.
Selegiline: The drug selegiline may have a benefit equivalent to vitamin E but has more side effects.
Estrogen: Estrogen does not improve cognition when administered to a woman with Alzheimer's disease. In one initial study, researchers at the National Institute on Aging found evidence that giving estrogen to postmenopausal women might lower susceptibility to the changes in the brain associated with Alzheimer's disease. But other studies have found no decrease in risk of developing Alzheimer's disease or any cognitive improvement using estrogen replacement therapy. Because ERT may cause uterine bleeding and its long-term use may be associated with an increased risk of breast cancer, ERT is not routinely used in women with Alzheimer's disease.
Nonsteroidal anti-inflammatory drugs (NSAIDs): Studies of NSAIDs, a class of painkillers that includes ibuprofen and the cox-2 inhibitors, have not shown an ability to treat dementia, and these medications have significant side effects in older adults.
Studies are ongoing with cholesterol-lowering medications, certain diabetes medications, and folic acid supplements.

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