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Cholinesterase inhibitors

Here’s How Cholinesterase Inhibitors Work for Alzheimer’s

By Simon Spichak, MSc | May 6th, 2022

Cholinesterase inhibitor drugs could help turn back the clock on Alzheimer’s symptoms by treating cognitive impairment.

More than a third people over the age of 85 will get Alzheimer’s disease during their lifetime. As the population of many countries around the world ages, the amount of people who develop Alzheimer’s is expected to double by 2030

The majority of treatments, including acetylcholinesterase inhibitors (also called cholinesterase inhibitors), target the cognitive symptoms of the disease. This does not prevent the disease from progressing or restore dying or damaged parts of the brain. However, these treatments may be useful for managing the cognitive symptoms of Alzheimer’s. 

First approved in 1997, cholinesterase inhibitors are a class of drugs that treat cognitive impairment and allow people to manage everyday tasks — like cleaning, dressing themselves or brushing their teeth. 

While not without side effects, cholinesterase inhibitors can provide symptomatic relief to people living with Alzheimer’s. 

How Do Cholinesterase Inhibitors Work?

Neurons can communicate with each other through chemical messengers called neurotransmitters. Acetylcholine — one such neurotransmitter — is involved in many important brain functions. It is released by neurons located in the basal forebrain, an area that starts to die early in Alzheimer’s. 

In Alzheimer’s, acetylcholine is no longer being sent to other regions of the brain, leading to impairments in: 

Cholinesterase inhibitors help mitigate these issues. Normally, after acetylcholine has reached and activated another neuron, it is recycled by an enzyme. This class of drugs blocks the enzyme, making acetylcholine and its effects last longer.

Currently, there are three approved drugs within this class:

  • Galantamine (brand name Razadyne)
  • Donepezil (brand name Aricept)
  • Rivastigmine (brand name Exelon)

Why Cholinesterase Inhibitors Treat Alzheimer’s Symptoms

Acetylcholine is one of the most common neurotransmitters in the human body. It is no surprise that some of its functions overlap with the deficits that occur in Alzheimer’s disease. 

Galantamine, one of the cholinesterase inhibitor drugs FDA-approved to treat mild to moderate Alzheimer’s dementia symptoms, may have secondary effects in the brain, making neurons more sensitive to acetylcholine. A recent study renewed interest in galantamine: Compared to donepezil and rivastigmine, people taking galantamine were less likely to develop severe dementia. 

Dr. Andrew Budson, chief of cognitive and behavioral neurology at the Veterans Affairs Boston Healthcare System and professor of neurology at Boston University, explained how cholinesterase inhibitor drugs work: “One way to think about Alzheimer’s disease is as a clock that is ticking down until you run out of time, and your memory and other cognitive functions are gone,” Budson told Being Patient in a discussion about galantamine. “By blocking the metabolism of acetylcholine, the acetylcholinesterase inhibitors drugs galantamine, donepezil, and rivastigmine can boost up memory equivalent to turning back the clock on Alzheimer’s disease by six to 12 months.”

Side Effects of Acetylcholinesterase Inhibitors

Common side effects of these drugs include: 

  • Nausea
  • Diarrhea
  • Vomiting
  • Decreased appetite
  • Loss of appetite
  • Muscle cramps
  • Fatigue
  • Insomnia
  • Dizziness
  • Headache

It is recommended to take with a full meal as it can reduce some of the gastrointestinal side effects. 


According to available data, cholinesterase inhibitors do appear to be an effective treatment for Alzheimer’s disease’s cognitive symptoms.  

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