How Is Alzheimer's Disease Treated?

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Several prescription drugs are approved by the U.S. Food and Drug Administration (FDA) for Alzheimer’s disease to help either manage the symptoms of or to treat the disease. Most FDA-approved drugs work best for people in the early or middle stages of Alzheimer’s. There are currently no known interventions that will cure Alzheimer’s.

Medications for mild to moderate Alzheimer’s disease

Treating the symptoms of Alzheimer’s can help provide people with comfort, dignity, and independence for a longer period of time and also assist their caregivers. Galantamine, rivastigmine, and donepezil are cholinesterase inhibitors that are prescribed for mild to moderate Alzheimer’s symptoms. These drugs may help reduce or control some cognitive and behavioral symptoms.

Cholinesterase inhibitors prevent the breakdown of acetylcholine, a brain chemical believed to be important for memory and thinking. As Alzheimer’s progresses, the brain produces less acetylcholine and, over time, these medicines lose their effectiveness. Because cholinesterase inhibitors work in a similar way, switching from one to another may not produce significantly different results, but a person living with Alzheimer’s may respond better to one drug versus another.

Lecanemab is an FDA-approved immunotherapy to treat early Alzheimer’s. It targets the protein beta-amyloid to help reduce amyloid plaques, one of the hallmark brain changes in Alzheimer’s. Clinical studies to determine the effectiveness of lecanemab were conducted only in people with early-stage Alzheimer’s, or mild cognitive impairment due to the disease. Study results showed lecanemab slowed the rate of cognitive decline among study participants over the course of 18 months and reduced the levels of amyloid in the brain. Currently, insurance may only cover this medication in specific situations.

Before prescribing this medication, doctors may order PET scans or an analysis of cerebrospinal fluid to evaluate whether amyloid deposits are present in the brain. Possible side effects of this medication include brain swelling and bleeding. In rare instances, the side effects may be serious or life-threatening. Due to this potential risk, monitoring with routine MRIs is required.

Several other medications to treat Alzheimer’s are being tested in people with mild cognitive impairment or early Alzheimer’s.

Medications for moderate to severe Alzheimer’s disease

A medication known as memantine, an N-methyl-D-aspartate (NMDA) antagonist, can be prescribed for moderate to severe Alzheimer’s. This drug is prescribed to decrease symptoms, which could enable some people to maintain certain daily functions a little longer than they would without the medication. For example, memantine may help a person in the later stages of the disease maintain their ability to use the bathroom independently for several more months, a benefit for both people with Alzheimer’s and their caregivers.

Memantine is believed to work by regulating glutamate, an important brain chemical. When produced in excessive amounts, glutamate may lead to brain cell death. Because NMDA antagonists work differently from cholinesterase inhibitors, the two types of drugs can be prescribed in combination.

The FDA has also approved donepezil, the rivastigmine patch, and a combination medication of memantine and donepezil for moderate to severe Alzheimer’s.

Brexpiprazole is an atypical antipsychotic that has been approved to treat agitation associated with Alzheimer’s. See below for more information on managing behavioral symptoms and antipsychotics.

Dosage and side effects of Alzheimer's disease medications

Doctors usually start patients at low drug doses and gradually increase the dosage based on how well a patient tolerates it. There is some evidence that certain people may benefit from higher doses of Alzheimer’s medications. However, the higher the dose, the more likely unwanted side effects will occur.

Patients should be monitored when a drug is started. All of these medicines have possible side effects that may include nausea, vomiting, diarrhea, allergic reactions, loss of appetite, headaches, confusion, dizziness, and falls. Report any unusual symptoms to the prescribing doctor right away.

It is important to follow your doctor’s instructions when taking any medication, including vitamins and herbal supplements. Talk with your doctor before adding or changing any medications.

• Alzheimer’s disease medications

  The following list provides an overview of Alzheimer’s medications. Talk with your health care providers about your options and which ones may be most appropriate for you.

  FDA-approved medications to manage symptoms

  • Brexpiprazole. Atypical antipsychotic. Treats agitation resulting from Alzheimer’s. Possible side effects include common cold symptoms, dizziness, high blood sugar, and stroke. Delivered once a day through a tablet.
  • Donepezil. Cholinesterase inhibitor. Treats symptoms of mild, moderate, and severe Alzheimer’s by preventing the breakdown of acetylcholine in the brain. Possible side effects include nausea, vomiting, diarrhea, insomnia, muscle cramps, fatigue, and weight loss. Delivered once a day through a tablet.
  • Galantamine. Cholinesterase inhibitor. Treats symptoms of mild to moderate Alzheimer’s by preventing the breakdown of acetylcholine and stimulates nicotinic receptors to release more acetylcholine in the brain. Possible side effects include nausea, vomiting, diarrhea, decreased appetite, weight loss, dizziness, and headache. Delivered through an extended-release capsule taken once a day or through a tablet or liquid taken twice a day.
  • Memantine. NMDA antagonist. Treats symptoms of moderate to severe Alzheimer’s by blocking the toxic effects associated with excess glutamate and regulates glutamate activation. Possible side effects include dizziness, headache, diarrhea, constipation, and confusion. Delivered once or twice a day through a tablet, liquid, or an extended-release capsule.
  • Memantine and Donepezil (manufactured combination). NMDA antagonist. Treats symptoms of moderate to severe Alzheimer’s by blocking the toxic effects associated with excess glutamate and prevents the breakdown of acetylcholine in the brain. Possible side effects include headache, nausea, vomiting, diarrhea, dizziness, anorexia, and ecchymosis (small bruising from leaking blood vessels). Delivered through an extended-release capsule once a day.
  • Rivastigmine. Cholinesterase inhibitor. Treats symptoms of mild, moderate, and severe Alzheimer’s by preventing the breakdown of acetylcholine and butyrylcholine (a chemical similar to acetylcholine) in the brain. Possible side effects include nausea, vomiting, diarrhea, weight loss, indigestion, decreased appetite, anorexia, and muscle weakness. Delivered through a capsule twice a day or through a skin patch that is replaced once a day.

  FDA-approved medications to treat Alzheimer's

  • Lecanemab. Disease-modifying immunotherapy. Treats mild cognitive impairment or mild Alzheimer’s by removing abnormal beta-amyloid to help reduce the number of plaques in the brain. Possible side effects include brain swelling and bleeding, headache, cough, diarrhea, nausea, vomiting, fever, chills, body aches, fatigue, high blood pressure, low blood pressure, and low oxygen. Delivered through IV over one hour every two weeks.

For more information about treating Alzheimer's disease

This content is provided by the NIH National Institute on Aging (NIA). NIA scientists and other experts review this content to ensure it is accurate and up to date.

Content reviewed: September 12, 2023