What Are the Treatments for Alzheimer’s Disease?

“It doesn’t stop the disease, and it doesn’t make people get better, but it slows down the rate where people get worse,” says Ronald Petersen, M.D., director of the Mayo Clinic Alzheimer’s Disease Research Center. 

Kisunla, made by Lilly and approved by the FDA in July 2024, slowed the loss of thinking and memory skills in a phase 3 study comparing the drug with placebos in patients with early stage Alzheimer’s disease.

This drug “seems to get rid of the amyloid at the core of the plaques,” Leverenz says. “There’s a feeling that this amyloid is what drives the development and progression of the disease early on.”

In an 18-month study giving Kisunla infusions every four weeks compared with placebos, the drug slowed cognitive decline by 38 percent, researchers reported in July in JAMA. Once amyloid levels dropped below a certain level, the drug was stopped.

There are important limitations on the use of Leqembi and Kisunla.

The FDA says the drugs are only for those with mild cognitive impairment or mild-stage dementia.

A person with MCI functions independently but with some inefficiency in daily activities. A person with mild dementia may have memory loss and confusion and trouble handling finances, problems that interfere with independence.

The drugs have a risk, called ARIA, which stands for amyloid-related imaging abnormalities. ARIA usually shows as bleeding of the brain that may be accompanied by swelling. In the large Leqembi study, about 13 percent of patients experienced brain swelling. In the Kisunla study, 25 percent of patients taking the drug experienced brain swelling. Most of these side effects disappeared within four months. 

Because people with two copies of the APOE e4 gene variant, which raises risk for Alzheimer’s disease, are more likely to experience ARIA, patients considered for Leqembi or Kisunla should be tested for APOE e4. Patients taking blood thinners are also at greater risk of brain bleeds while taking these drugs.

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A review of 31 studies of drugs that clear amyloid plaques, published in March 2023 in the journal Neurology, pointed out some brain shrinkage with these drugs. But what shrinks away are the amyloid plaques, says Nick Fox, M.D., professor of neurology and director of the Dementia Research Centre at University College London. “The brain volume shrinkage is related to amyloid removal; amyloid plaques occupy a significant volume in the cortex of the brain in Alzheimer’s disease,” he wrote in an email. “Studies show these plaques can be extensively removed by the immunotherapies thereby leading to a reduction in brain volume.” His paper supporting this conclusion is scheduled for September publication in Lancet Neurology.

What might future treatments look like?

​Amyloid-clearing drugs may need to be paired with other types of drugs designed to remove a protein called tau from the brain. In Alzheimer’s disease, tangles of abnormal tau form inside nerve cells, causing problems in communication between nerve cells. Several tau-removing drugs are being tested in people with Alzheimer’s, including Biogen’s BIIB080, which reduced tau levels by more than 50 percent in a very early clinical trial of 46 patients with early disease.

Researchers, including those supported by AARP and others through the Dementia Discovery Fund, are developing and testing several other approaches to treat Alzheimer's and other dementias.

Drugs to ease behaviors and other symptoms

Several medications are available to treat certain Alzheimer’s symptoms, and some are used for other forms of dementia as well. These treatments do not slow progression of disease. They include:

• Cholinesterase inhibitors. These drugs prevent the breakdown of a brain chemical called acetylcholine that’s important for memory and thinking, says Gary Small, M.D., at Hackensack Meridian Health in New Jersey. Three examples are Aricept (donepezil), Exelon (rivastigmine) and Razadyne (galantamine), all approved for Alzheimer’s. Exelon is also approved to treat dementia associated with Parkinson’s disease.
• Namenda (memantine). This drug inhibits the activity of a brain chemical called glutamate, which sends messages between nerve cells. In Alzheimer’s disease, nerve cells make too much glutamate, which causes damage and cell death. Namenda is approved for people with moderate to severe Alzheimer’s disease. The drug can be used on its own or with a cholinesterase inhibitor, Small says.
• Belsomra (suvorexant). The drug inhibits a brain chemical called orexin, which can keep a person awake. Belsomra is approved to treat insomnia in people with Alzheimer’s disease.

Doctors may prescribe the drugs below to help treat symptoms that may appear in later stages of the disease:

• Antidepressants such as Zoloft (sertraline) to improve mood and irritability, although studies have questioned their effectiveness.
• Antipsychotic medications such as Risperdal (risperidone) or Haldol (haloperidol) for hallucinations, delusions, aggression or agitation. These drugs may not be appropriate for people with Lewy body dementia or Parkinson’s disease dementia, Petersen cautions, as they may worsen behavioral symptoms.
• The first anti-agitation drug to receive FDA approval, which occurred in May 2023. Rexulti (brexpiprazole) is prescribed for Alzheimer’s-related agitation, from pacing and restlessness to verbal and physical aggression. The drug comes with a black box warning, the FDA’s strongest, of an increased risk for death in older people with dementia.

Although there are medications to treat other forms of dementia, they are usually geared to a specific condition, Petersen says. The treatment for vascular dementia, for example, is often aimed at improving blood vessel health, which means getting control of risk factors such as high blood pressure, type 2 diabetes and being overweight.

Editor’s note: This story, originally published Jan. 17, 2024, has been updated with new information.