A new study by the Rush Institute for Healthy Aging in Chicago estimates that the number of people living with Alzheimer’s Disease will triple by the year 2050. Like other forms of dementia, Alzheimer’s is characterized by deterioration in cognitive function that ultimately results in difficulty performing life’s every day activities.
Once Alzheimer’s Disease occurs, there is currently no treatment to reverse it or even stop it from getting worse. There are two types of prescription medications that have been shown to influence the course of Alzheimer’s disease progression. One type of medication, called acetylcholinesterase inhibitors, raises the level of a neurotransmitter called acetylcholine in the space (synapse) between neurons. Examples of these drugs are Aricept (Donepezil), Razadyne (Galantamine), and the Exelon patch (Rivastigmine). Studies show that the average person treated with an acetylcholinesterase inhibitor has a small improvement in cognition and in performing daily life activities.
The second type of prescription medication used to affect the course of Alzheimer’s Disease is Namenda (Memantine). It works by blocking a receptor called NMDA.
The current standard of care in treating a person with Alzheimer’s Disease is to start an acetylcholinesterase inhibitor such as Aricept. It is unclear whether adding Namenda offers additional benefit once a person is already taking an acetylcholinesterase inhibitor. While one study seemed to show that adding Namenda slowed the progression of Alzheimer’s, two others did not find this to be the case. Now a study published in the January 1, 2014 issue of the Journal of the American Medical Association shows that while combining Namenda with an acetylcholinesterase inhibitor was not helpful, adding Vitamin E resulted in a slower functional decline.
Researchers selected 613 patients with mild to moderate Alzheimer’s Disease who were already taking an acetylcholinesterase inhibitor. While continuing to take their acetylcholinesterase inhibitors, these patients were randomized to take either 1) Vitamin E, 2) Namenda, 3) Vitamin E plus Namenda, or 4) a placebo. The dose of Namenda was 10 mg twice daily and the dose of Vitamin E was 2,000 IU daily.
After roughly 5 years, researchers found that compared to placebo, patients taking Vitamin E had less deterioration in their ability to perform activities of daily living. This effect was not seen in the groups taking a) Namenda plus Vitamin E or b) Namenda alone.
These results call into question the common practice of adding Namenda to an acetylcholinesterase inhibitor in patients with Alzheimer’s Disease. I wonder if some of us have been prescribing both medications more out of a desire to offer “everything available” than on the grounds of sound evidence. Based on this recent study, it looks like we might better serve patients with Alzheimer’s by adding Vitamin E instead.