What Are Cholinesterase Inhibitors for Alzheimer's Disease?

Medically Reviewed by Sabrina Felson, MD on August 08, 2022
3 min read

Most medicines for people with Alzheimer’s disease work to improve the symptoms, rather than treat the disease itself. A kind of drug often prescribed soon after you’re diagnosed is called a cholinesterase inhibitor. While these drugs don’t change the course of the disease, they may help you with thinking and memory problems.

Cells in your brain called neurons make a chemical called acetylcholine that helps brain cells communicate with each other. It has a role in many cognitive functions, including:

  • Attention
  • Learning
  • Memory
  • Information processing

It’s also involved in regulating your sleep and helping you respond to stress.

Alzheimer’s disease destroys the neurons that make acetylcholine. So over time, you have less than you need. The acetylcholine you do have is gradually broken down as it gets used. Cholinesterase inhibitors slow this process. That makes more of the chemical available to your brain for as long as possible.

The FDA has approved three cholinesterase inhibitors for Alzheimer’s treatment.

Donepezil (Aricept) treats mild, moderate, and severe Alzheimer’s disease.

  • You take it once a day either as a tablet you swallow or one that dissolves in your mouth.
  • Side effects include fatigue, muscle cramps, nausea, vomiting, loss of appetite, and diarrhea.

Donepezil plus memantine (Namzaric) combines a cholinesterase inhibitor with a different Alzheimer’s medication called an NMDA agonist. The NMDA agonist works to control levels of a different brain chemical called glutamate. The combination is approved to treat moderate to severe Alzheimer’s.

  • You take this once a day as a tablet you swallow.
  • Side effects can include headache, confusion, dizziness, constipation, nausea, vomiting, loss of appetite, and diarrhea.

Galantamine (Razadyne) is used to treat mild-to-moderate Alzheimer’s disease.

  • You take this either twice a day as a tablet you swallow, or once a day as an extended-release capsule.
  • Side effects include headaches, dizziness, nausea, vomiting, loss of appetite, and diarrhea.

Rivastigmine (Exelon) is used for mild to moderate Alzheimer’s disease. In patch form, it’s approved for severe Alzheimer’s too.

  • You take this twice a day as a capsule you swallow. It also comes as a patch you stick to your skin and change daily.
  • Side effects include muscle weakness, indigestion, nausea, vomiting, loss of appetite, and diarrhea. You may have fewer digestive side effects if you use the patch instead of the pill.

If you have side effects when you start taking a cholinesterase inhibitor, they may go away as you get used to the medicine. Your doctor may be able to give you tips to help you manage them, like taking your medication with meals.

Your doctor will probably start you on a low dose and increase it if the side effects don’t bother you. Not everyone responds to every one of these drugs, and they may not work for you at all. You may need to try more than one to find what’s right for you.

Research has found that many people who take cholinesterase inhibitors have modest improvement of their symptoms that can last for several years. You may find you’re able to think more clearly, learn and remember things better, and manage your daily activities more easily. There doesn’t appear to be a difference in how well these drugs work based on your age, gender, or ethnicity.

But the effects of cholinesterase inhibitors are temporary. The drugs don’t stop or fix the damage that Alzheimer’s does to your brain. Eventually, your brain stops making enough acetylcholine for cholinesterase inhibitors to help anymore.

Cholinesterase inhibitors can lower your heart rate and blood pressure. If you already have an unusually slow heartbeat or you take high blood pressure medication, they can make you likely to faint and fall. They might not be a good choice for you if you have:

  • Asthma
  • Certain abnormal heart rhythms (or heartbeats)
  • Kidney disease
  • Liver disease
  • Ulcers

To avoid dangerous interactions, make sure your doctor knows about all medicines and supplements you take.

You should not take a kind of drug called an anticholinergic while you’re taking a cholinesterase inhibitor. Anticholinergics are prescribed for things like depression, psychosis, and bladder problems. They’re also in some over-the-counter cold medicines and sleep aids. The drugs work opposite each other and combining them can make both work poorly.