Drug Therapy for Alzheimer's

Writer: Prahalad Srinivasan

Editor: Vijaya Varadarajan & Brianna Viets

As one of the most commonly diagnosed brain disorders in the USA, Alzheimer's Disease affects over 3 million Americans each year. Due to the severity and redundancy of the disorder, different drug therapies are administered to patients in an attempt to reduce the effects the disease has on the human body. While there is currently no definite cure for Alzheimer's, multiple drugs are approved by the FDA to treat the disorder.

Approved Drugs:

Currently, there are 3 drugs approved by the Food and Drug Administration (FDA) for usage against Alzheimer's:

The Generic Name of each drug is given, along with the trade name in parenthesis.

Galantamine (Razadyne®) - taken as a pill

Rivastigmine (Exelon®) - taken as a pill

Donepezil (Aricept®) - taken as a pill

Memantine (Namenda®) - taken as a syrup

Galantamine, Rivastigmine, and Donepezil are grouped as cholinesterase inhibitors, meaning they work to boost levels of acetylcholine in the brain. When cholinesterase inhibitors enter the blood flow, they bind to receptors, triggering the release of the chemical acetylcholine. This means acetylcholine allows neurons to connect and transmit information throughout the brain, the primary function affected by Alzheimer’s Disease.

Memantine is grouped as an NMDA (N-Methyl-D-Aspartate) antagonist, meaning it binds to receptors to prevent the effects of a chemical called glutamate. Glutamate is released in excessive amounts by nerve cells affected by Alzheimer’s and can lead to the destruction of other functioning nerve cells in the brain. By binding to the NDMA receptor, memantine is able to prevent excessive amounts of glutamate from being released, controlling the damage Alzheimer’s can cause to the patient’s brain.

Treatment Plans:

Different drugs must be used to manage and treat the different stages of Alzheimer’s differently. Drugs with different effects can also be used in combination in order to restrict several different effects of the disease.

Stages of Alzheimer’s Disease (Farr Law Firm)

Mild to Moderate Alzheimer's:

Currently, the 3 FDA-approved cholinesterase inhibitors for Alzheimer’s treatment (Galantamine, Rivastigmine, and Donepezil) are most effective in controlling mild to moderate symptoms. If identified in an earlier stage, these drugs can be used to reduce the impacts of the disease over a longer period of time.

Moderate to Severe Alzheimer's:

Currently, the only FDA-approved NMDA antagonist, Memantine, is deemed most effective for controlling more moderate to severe stages of Alzheimer’s. They are often taken along with the cholinesterase inhibitors to produce a stronger effect in order to reduce symptoms for as long as possible.

Efficacy:

Ultimately, Alzheimer's Disease damages and injures crucial nerve cells in the brain, greatly impacting basic functions of the central nervous system. Unfortunately, the disease cannot be completely removed from the brain either, because of the lasting impact the condition has on nerve cells. However, while researchers work to develop a long-term solution for Alzheimer’s, drugs can be used to control and restrict the spread of Alzheimer’s in the brain, allowing those affected to retain important functions for a longer period of time. This means the currently approved drugs are the best available solutions for Alzheimer's Disease, even though they are not 100% effective.

Now that we understand the available treatments for Alzheimer’s, we can evaluate Alzheimer’s links with other conditions. Make sure to tune in to our next blog post which will discuss the connection between Down Syndrome and Alzheimer’s.

Glossary:

Acetylcholine: a neurotransmitter that plays a role in memory, learning, attention, arousal and involuntary muscle movement

Bibliography:

“How Alzheimer’s Drugs Help Manage Symptoms.” Mayo Clinic, Mayo Foundation for Medical Education and Research, 30 Aug. 2023, www.mayoclinic.org/diseases-conditions/alzheimers-disease/in-depth/alzheimers/art-20048103.

“Medications for Alzheimer’s Disease.” Stanford Health Care (SHC) - Stanford Medical Center, stanfordhealthcare.org/medical-conditions/brain-and-nerves/alzheimers-disease/treatments/medications.html#:~:text=Treatment%20for%20mild%20to%20moderate,disease%20from%20worsening%20over%20time. Accessed 27 Oct. 2023.

“How Is Alzheimer’s Disease Treated?” National Institute on Aging, U.S. Department of Health and Human Services, www.nia.nih.gov/health/how-alzheimers-disease-treated. Accessed 27 Oct. 2023.

professional, Cleveland Clinic medical. “Acetylcholine (ACH): What It Is, Function & Deficiency.” Cleveland Clinic, my.clevelandclinic.org/health/articles/24568-acetylcholine-ach. Accessed 27 Oct. 2023.

Carvalho, Karinne Marieta, et al. Alzheimer’s Drug Table. Jan. 2015. ResearchGate, ResearchGate, https://www.researchgate.net/figure/FDA-approved-drugs-for-Alzheimers-disease-19_tbl1_282529834. Accessed 18 Nov. 2023.

Farr, Evan H. Progression of Alzheimer’s Disease. 26 Oct. 2018. Farr Law Firm, https://www.farrlawfirm.com/elder-law-blogs-news/the-7-stages-of-alzheimers/. Accessed 18 Nov. 2023.