Medications and How They Work

The current method of treatment for Alzheimer’s disease is focused around slowing the progression of the disease since a cure for Alzheimer’s disease has not been discovered yet.

The FDA (U.S. Food and Drug Administration) has approved 5 medications for this treatment of symptoms (see Figure above).

These 5 medications can be divided into 2 categories based on how they work in the body. 

The first category, cholinesterase inhibitors, includes four of the five drugs: donepezil (Aricept), galantine (Razadyne), rivastigmine (Exelon), and tacrine Cognez), and the second category, NMDA receptor antagonists, includes memantine (Namenda).

In order to understand how these drugs work on the brain, we must first understand how a normal brain works. The brain is similar to mass communication system, with chemicals that are passed between brain cells  (these chemicals are called neurotransmitters) that serves as messengers to pass the information along from cell to cell. In Alzheimer’s disease, this communication pathway is damaged causing the brain to lose information (memory loss, etc.) and make it more difficult for the brain to learn new things. 

Cholinesterase inhibitors prevent a very important neurotransmitter (Acetylcholine) from being broken down (by a protein called cholinesterase). This allows the neurotransmitter to stay active in the brain longer, promoting continued communication among the brain cells.

NMDA (N-methyl-D-aspartate) receptor antagonists focus on slowing the process of cell damage in Alzheimer’s disease as apposed to promoting communication directly. NMDA receptor antagonists prevents a different neurotransmitter (glutamate) from working on its targeting brain cell (also known as a neuron). In Alzheimer’s disease, there is too much glutamate release from damaged cells, leading to a faster progression of cell damage. NMDA receptor antagonists prevent glutamate from doing its job as effectively, which can slow down the progressive cell damage process.

Figure: FDA-approved drugs. (n.d.). Retrieved February 6, 2015.

Source: Current Alzheimer's Treatments. (n.d.). Retrieved February 6, 2015, from http://www.alz.org/research/science/alzheimers_disease_treatments.asp#how