The projected prevalence of dementia over the coming decades poses significant challenges to medical services in being able to meet targets for early diagnosis, access to treatment and post-diagnostic support.
Dementia is not a specific disease but rather it is a collection of symptoms that can have several possible causes. The most prevalent type of dementia is Alzheimer’s disease, but there are many other subtypes of dementia including Vascular, Parkinson’s disease, Lewy Body, frontotemporal, head trauma, and HIV/AIDS. As such, the term dementia is considered an umbrella term for a set of symptoms causing a person to have brain changes that interfere with the ability to function and do everyday activities. In addition, there are some types of dementia that are considered reversible, while others cannot be cured at this time.
As far as medication goes, there has been no medication for Alzheimer’s disease approved by the FDA in 18 years. Currently there are three acetylcholinesterase inhibitors that have been approved and available, which include donepezil, galantamine and rivastigmine. These provide symptomatic relief and, at best, may improve the quality of life for people by slowing the progression of cognitive decline.
Unfortunately, there is no current drug treatment that will alter the underlying neuropathological disease process. Nonetheless, at least the current pharmacological treatment does offer some brief symptomatic relief. As with all pharmacological medication the expectations of treatment outcomes need to be carefully managed by the prescriber.
There are two types of medication used to treat Alzheimer’s disease: acetylcholinesterase inhibitors and NMDA receptor antagonists.
Acetylcholinesterase Inhibitors
Donepezil was originally patented as the brand name Aricept, but is more widely available now as just generic donepezil.
Rivastigmine was patented as Exelon and is now also available as other brands, as well as generic rivastigmine.
Galantamine is also known as Razadyne and has been approved for mild-to-moderate stages of Alzheimer’s disease.
NMDA receptor antagonists
Memantine, an NMDA receptor antagonist is an option for managing moderate Alzheimer’s disease in people who are intolerant of or have a contraindication to acetylcholinesterase inhibitors, or those who have advanced stage Alzheimer’s disease.
The cholinergic hypothesis asserts that Alzheimer’s disease is caused by reduced synthesis of the neurotransmitter acetylcholine. This is one of a number of competing hypotheses. It forms the basis for three of the medications that have been approved for use by the FDA. Acetylcholinesterase inhibitors aim to reduce the rate at which acetylcholine is broken down, increasing its concentration.
NMDA receptor antagonists are designed to act on the glutamatergic system by blocking NMDA-type glutamate receptors. The hypothesis that underpins memantine use suggests that glutamate is released in excessive amounts when brain cells are damaged as part of the disease process, which then in itself causes brain cells to be damaged further. Memantine is believed to offer some protection against the potential effects of excess glutamate.
Aducanumab is an experimental drug designed to use antibodies (immune proteins) to remove abnormal amyloid beta proteins from the brain in people with Alzheimer’s disease. The antibody preferentially binds to the aggregated amyloid-beta. This is because it targets an epitope that is not normally accessible in the amyloid-beta monomer. Through this interaction, aducanumab could reduce the number of amyloid plaques present in the brain. Which ultimately may slow neurodegeneration and disease progression. Currently, aducanumab is being considered by the FDA for approval after a rollercoaster ride.
If you or your loved one is worried about new and progressive concerns with memory, language or behavior, you should consult with a medical doctor and specifically consider a referral to a neurologist. Your neurologist may then refer you for a neuropsychological evaluation such as the ones that Dr. Burchette performs for patients seeking an assessment for their memory, language, or thinking concerns. Your neurologist will still be the best resource for helping you to navigate any medications that might be right for your current care. Please consult with your physician before initiating or discontinuing any medications.
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