Medications for Alzheimer's Disease

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MINDY KIM-MILLER, MD, PhD
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Question:

My mother-in-law was recently diagnosed with Alzheimer’s disease. What medications can she take for it?

–Anonymous, IL

Answer:

While there is no cure for Alzheimer’s disease (AD), there are medications that may slow disease progression and help improve memory and function in those with AD. Medications can also help manage some of the more challenging symptoms of AD, including agitation, aggression, depression, and sleep issues. By working with healthcare professionals, you can help determine the best treatment for your loved one with AD. Here are a few types of treatments:

Cholinesterase Inhibitors

The available cholinesterase inhibitors include:

  • Rivastigmine (trade name Exelon®): Approved by the Federal Drug Administration (FDA) to treat mild to moderate AD.
  • Galantamine (trade name Razadyne®, formerly Reminyl®): FDA-approved to treat mild to moderate AD.
  • Donepezil (trade name Aricept®): This is the only treatment approved by the FDA to treat all stages of AD – mild, moderate, and severe. It may also delay the onset of AD in people who have mild cognitive impairment (MCI) for about a year.
  • Tacrine (trade name Cognex®): No longer marketed due to its side effects.

Cholinesterase inhibitors increase the level of acetylcholine, a chemical in the brain used for memory and learning. In AD, the brain makes less acetylcholine. By slowing the breakdown of acetylcholine, cholinesterase inhibitors can improve or delay cognitive and functional impairments in about half of the people who take them.

Possible side effects of cholinesterase inhibitors include diarrhea, vomiting, nausea, fatigue, and insomnia. Because of varying response and side effects and possible interactions with other medications, doctors may try different cholinesterase inhibitors until the most effective one is found for each individual.

NMDA Antagonist

Memantine (trade name Namenda®) is approved for the treatment of moderate to severe AD. It can delay progression of behavioral and psychological symptoms and help those with AD to maintain abilities such as going to the bathroom independently for a little longer.
Memantine works by blocking a glutamate receptor called N-methyl D-aspartate (NMDA). Glutamate is a brain chemical that, in high levels, may lead to brain cell death. In AD, the brain makes too much glutamate. Memantine helps decrease glutamate activity, which may help slow the loss of brain cells and delay disease progression. Possible side effects of memantine include dizziness, confusion, tiredness, headache, constipation, and sometimes agitation and delusions.

Studies suggest that combination therapy using memantine with a cholinesterase inhibitor (donepezil, rivastigmine, or galantamine) may be more effective than using either alone. Once a person starts taking these medications for AD, it is important to continue taking them, as studies suggest that stopping them can lead to rapid progression of symptoms.

Additional Treatments

In addition to the FDA-approved drugs for treating AD, the American Academy of Neurology has stated that vitamin E supplements (alpha-tocopherol) may delay symptom progression in some people with AD. However, there is currently no evidence that vitamin E is effective in slowing the progression of MCI to AD. One should consult a physician prior to taking vitamin E due to possible side effects, including increased risk of bleeding.

Alternative treatments for AD are also available, including dietary supplements. Most of these are not regulated by the FDA or quality-controlled. There may be limited research on their effectiveness and side effects. Please consult a physician before starting an alternative treatment as there may be serious side effects or drug-drug interactions.

A popular supplement for AD treatment that is currently not FDA-approved is Ginkgo biloba. Studies have been inconsistent regarding its efficacy. Some studies report that Ginkgo biloba is safe and may improve or stabilize mental and social functioning in those with dementia. One study found that it was as effective as donepezil in treating AD.

Medications are also available for the management of some of the behavioral symptoms of AD. For example, anti-psychotic medications can help treat psychosis and paranoia. Anti-anxiety medications can help manage agitation and aggression. However, there is a high risk of side effects and drug-drug interactions among the elderly and those with AD. In general, non-drug therapies for behavioral symptoms can be effective in all stages of AD and should be attempted before starting drug therapy. If drug therapy for behavioral symptoms is necessary, it should be used in conjunction with non-drug therapies. With any medication, one should be cautious and work with healthcare professionals, especially when using multiple medications.

Dr. Mindy Kim-Miller is a trained medical physician who provides useful, but general answers to questions provided by online visitors. While Dr. Mindy can not provide specific medical advice or services, we hope you find her responses useful in your personal education. All information is provided for informational and educational purposes only and is not meant to be a substitute for professional medical advice, diagnosis or treatment. If you suspect you have an illness or disease, or a health related condition of any kind, seek professional medical care with an appropriate health care professional immediately. Do not postpone or delay seeking treatment or disregard professional advice based upon the general answers provided by Dr. Mindy. Dr. Mindy’s advice is not intended to substitute for a visit to your personal physician or other qualified health provider. Any specific medical concerns or questions you may have should be directed to your personal physician or other qualified health provider.

References:

Alzheimer’s Association. (2007) FDA-approved treatments for Alzheimer’s. http://www.alz.org/national/documents/topicsheet_treatments.pdf.
Daiello LA. (2007) Current issues in dementia pharmacotherapy. Am J Manag Care. 13 Suppl 8:S198-202.
Hill C. (2008) Treatment of Alzheimer’s. About.com. http://alzheimers.about.com/od/treatmentofalzheimers/a/treatments.htm.
Mazza M, Capuano A, Bria P, et al. (2006) Ginkgo biloba and donepezil: a comparison in the treatment of Alzheimer’s dementia in randomized placebo-controlled double-blind study. Eur J Neurol. 13:981-5.
National Institute on Aging. (2008) Alzheimer’s disease medications fact sheet. http://www.nia.nih.gov/Alzheimers/Publications/medicationsfs.htm.
Seow D, Gauthier S. (2007) Pharmacotherapy of Alzheimer disease. Can J Psychiatry. 52:620-9.