Medication for Dementia - Memantine
This week let’s deep dive into another medication approved for dementia, specifically for Alzheimer’s disease, memantine. Memantine, also known as Namenda in the United States, was originally approved for treatment of moderate to severe Alzheimer’s disease in 2003, but had been around and researched for decades prior to that as a potential anti-diabetic medication.
Memantine is commonly used to try to slow progression of moderate to severe Alzheimer’s disease in conjunction with donepezil. Donepezil targets the acetylcholine system in the brain, whereas memantine targets NMDA (N-methyl-D-aspartate) receptors. The goal of memantine is to block this receptor from its normal neurotransmitter to decrease the excessive stimulation of this receptor that is present in Alzheimer’s disease. Memantine also has several other places it is active in the brain, but this action at the NMDA receptor is the main function.
Currently the data supporting memantine is limited to persons with moderate to severe Alzheimer’s disease. There is a small benefit over six months, which is the usual study time for medications used in dementia, in areas of cognition and ability to perform activities of daily living. One small study did extend treatment for another six months and showed continued benefit. A challenging issue with medications used in dementia is that they may show some statistical significance in studies, but none have proven to be clinically significant. This means that over six months people may score better on research criteria and tests, but ultimately will continue to progress and decline in cognition and function. One study with long term follow up showed after four years, memantine use had no effect on institutionalization (moving to a nursing home). There is no data to support its use in mild Alzheimer’s disease.
Memantine is generally very well tolerated, but it does have side effects; most common are confusion and dizziness, which around 5% of people who take it will experience. More concerningly it can cause aggression and hallucinations, which, although rare, are definite indications to stop this medication.
Ultimately, the decision to take this medication to take this medication for treatment should be a shared and informed decision between the person affected, their loved ones, and the treating physician. Be sure to always talk to those who are important in your life about what Matters to you!
Key Points:
Memantine targets the NMDA receptors in the brain to decrease their over-stimulated state that is present in Alzheimer’s dementia
Current research only supports memantine for moderate to severe Alzheimer’s disease
Talk about what Matters with your loved ones!
