*The bottom line on medications for Alzheimer’s disease*
By Vimal Aga, MD. Board-certified Geriatric psychiatrist and Assistant Professor of Psychiatry,
Oregon Health Sciences University, Portland, OR.
*Overview of medications*
Four medications are currently FDA-approved for the treatment of Alzheimer’s disease.
1. Acetylcholinesterase inhibitors (also called cholinesterase inhibitors): donepezil (Aricept), rivastigmine (Exelon), and galantamine (Razadyne).
2. Memantine (Namenda) is in a class by itself; it is an NMDA receptor antagonist.
(In addition to these four primary medications, a variety of other medications are used to treat behavioral and psychological symptoms of dementia. They are not discussed here.)
The research can be confusing, so here is the bottom line regarding use of these four anti-dementia medications in Alzheimer’s disease:
Donepezil (Aricept) is FDA-approved for the entire spectrum from mild to severe Alzheimer’s disease. However, the recommended dose is different for mild to moderate (5 to 10 mg/day) and for moderate to severe (10 to 23 mg/day) disease.
Galantamine (Razadyne) and rivastigmine (Exelon) are FDA-approved to treat only mild to moderate Alzheimer’s disease. But note: it is not they have been shown to not work in severe Alzheimer’s disease, but just that there are no specific data to show that they do. There is no reason to believe that they are not effective for severe Alzheimer’s disease.
Memantine is effective for and FDA-approved for the treatment of moderate to severe 0Alzheimer’s disease.
In contrast to the cholinesterase inhibitors, the research shows that it is not effective for mild cases of Alzheimer’s disease. So, its use in mild cases is not recommended.
While memantine is FDA-approved for monotherapy in Alzheimer’s disease, it is probably best used as an add-on medication for moderate to severe dementia when the patient is already on a cholinesterase inhibitor.
In moderate to severe dementia, the combination of a cholinesterase inhibitor and memantine is more effective than either medication alone.
What symptoms would this combination help with? Combined treatment with a cholinesterase inhibitor plus memantine is:
– most helpful for behavioral problems,
– less helpful for cognition, and
– minimally helpful for activities of daily living
Which lobe is compromised by vascular episode also influences the choice of treatment by only cholinestrases inhibtors or mixed memantine or mixed MAO B inhibitors or dopamine agonists or Carbidopa and levodopa combination and also by some activating antidepressants like modafinil
Most of the vascular dementia have motor and behavioural variant both
No role of antipsychotics in motor variant