Alzheimer's drugs target symptoms, not underlying causes
BY DR. KOMOROFF Universal Uclick
Friday, November 16, 2012
11/16/12 at 4:34 AM
Dear Doctor K: Can you tell me about medications to treat Alzheimer's disease? How do they work?
Dear Reader: The drugs currently available to treat Alzheimer's disease target the symptoms but not the underlying causes of the disease. The memory loss, impaired thinking and personality changes seen in Alzheimer's disease come from a loss of neurons (nerve cells) and their connections with other neurons. The symptoms of Alzheimer's disease also come from a decline in levels of neurotransmitters - brain chemicals that carry messages between nerve cells.
Currently, no treatment prevents or stops Alzheimer's. However, medications can improve symptoms, though only temporarily.
The FDA has approved five drugs for the treatment of Alzheimer's disease: donepezil (Aricept), rivastigmine (Exelon), galantamine (Razadyne, formerly Reminyl), tacrine (Cognex) and memantine (Namenda). I've put a table of these medications, along with their side effects and some additional comments, on my website, tulsaworld.com/DrK
In some people, these drugs lead to modest improvements in memory and cognitive function (such as making decisions and exercising judgment).
Donepezil, rivastigmine, galantamine and tacrine belong to a class of drugs called cholinesterase inhibitors. They raise the levels of acetylcholine in the brain. (A deficiency in this neurotransmitter contributes to the memory problems.) The drugs are effective for mild to moderate Alzheimer's disease.
Memantine works differently. It blocks glutamate, another neurotransmitter. This is beneficial because too much glutamate can destroy neurons.
Will there ever be treatments that can prevent Alzheimer's disease, or that can reverse the disease once it starts? I am cautiously optimistic. Over the past 25 years, enormous progress has been made in understanding what causes Alzheimer's disease.
Write Dr. K at www.AskDoctorK.com or c/o Universal Uclick, 1130 Walnut, Kansas City, MO 64106