Alzheimer's: Drugs help manage symptoms

Alzheimer's still has no cure, but two types of drugs can help manage symptoms of the disease.

By Mayo Clinic Staff

Alzheimer's drugs might be one strategy to help slow or manage memory loss, thinking and reasoning problems, and day-to-day function. While Alzheimer's drugs don't cure the disease, they can improve quality of life and help prolong independence.

There are two types of medications approved to treat Alzheimer's: those that can temporarily ease some symptoms, and those that can slow the progression of the disease. Medications don't work for everyone, and they may lose effectiveness over time. They tend to be most effective for people with early to moderate Alzheimer's.

Research into more-effective Alzheimer's drugs is ongoing. If you can't take the approved medications or they don't work for you, ask your doctor if you might be eligible for a clinical trial.

Role of current Alzheimer's drugs

The Food and Drug Administration (FDA) has approved different types of drugs specifically to treat symptoms of Alzheimer's disease.

  • Cholinesterase inhibitors
  • Memantine

These drugs:

  • Are approved for specific Alzheimer's stages. These stages — mild, moderate and severe — are based on scores on tests that assess memory, awareness of time and place, and thinking and reasoning.

    Doctors might, however, prescribe Alzheimer's drugs for stages other than those for which the FDA has approved them. Alzheimer's stages aren't exact, individual responses to drugs vary and treatment options are limited.

    If your doctor prescribes medication as part of your Alzheimer's care plan, make sure you understand the drug's potential benefits and risks for your situation.

  • Are not approved for mild cognitive impairment (MCI). This condition, which involves subtle changes in memory and thinking, can be a transitional stage between normal age-related memory changes and Alzheimer's disease. Many people with MCI — but not all — eventually develop Alzheimer's or another dementia.

    Clinical trials testing whether Alzheimer's drugs might prevent progression of MCI to Alzheimer's have generally shown no lasting benefit.

Cholinesterase inhibitors

One way Alzheimer's disease harms the brain is by decreasing levels of a chemical messenger (acetylcholine) that's important for alertness, memory, thought and judgment. Cholinesterase (ko-lin-ES-tur-ays) inhibitors boost the amount of acetylcholine available to nerve cells by preventing its breakdown in the brain.

Cholinesterase inhibitors can't reverse Alzheimer's disease or stop the destruction of nerve cells. These medications eventually lose effectiveness because dwindling brain cells produce less acetylcholine as the disease progresses.

Common side effects can include nausea, vomiting and diarrhea. Starting treatment at a low dose and working up to a higher dose can help reduce side effects. Taking these medications with food also might help minimize side effects.

People with certain types of cardiac arrhythmias shouldn't take cholinesterase inhibitors.

Three cholinesterase inhibitors are commonly prescribed:

  • Donepezil (Aricept) is approved to treat all stages of the disease. It's taken once a day as a pill.
  • Galantamine (Razadyne) is approved to treat mild to moderate Alzheimer's. It's taken as a pill once a day or as an extended-release capsule twice a day.
  • Rivastigmine (Exelon) is approved for mild to moderate Alzheimer's disease. It's taken as a pill. A skin patch is available that can also be used to treat severe Alzheimer's disease.

Memantine for later stages

Memantine (Namenda) is approved by the FDA for treatment of moderate to severe Alzheimer's disease. It works by regulating the activity of glutamate, a messenger chemical widely involved in brain functions — including learning and memory. It's taken as a pill or syrup. Common side effects include dizziness, headache, confusion and agitation.

The FDA has also approved a combination of donepezil and memantine (Namzaric), which is taken as a capsule. Side effects include headache, dizziness, nausea and diarrhea.

When to discontinue Alzheimer's drugs

Because Alzheimer's is a progressive disease, your symptoms and care plan will change over time. If you're taking an Alzheimer's drug, ongoing review of your care plan will include working with your doctor to decide how long you should continue your medication.

Because the effects of Alzheimer's drugs are usually modest, it might be difficult to tell if the drugs are working. However, you can't know if your symptoms might be more severe without your medication.

Talk to your doctor before stopping an Alzheimer's drug, and let your doctor know if your condition worsens after you stop.

Working with your health care team can help you find the best strategies to manage your symptoms and prolong your independence.

Aducanumab

This intravenous infusion therapy is the first drug of its kind to be approved for Alzheimer's disease. It is approved only for patients with mild cognitive impairment and mild dementia due to Alzheimer's disease.

The FDA approved aducanumab under an accelerated approval provision because it reduced brain beta-amyloid, a protein that is thought to be a key part of the Alzheimer disease pathway.

However, the benefits on daily functioning, thinking or memory aren't clear. Side effects can include:

  • Amyloid related imaging abnormalities-edema (ARIA-E), in which the brain swells (edema)
  • Amyloid related imaging abnormalities-hemosiderin deposition (ARIA-H), which includes small brain bleeds (microhemorrhage) and brain bleeding along the surface of the brain (superficial siderosis)

Repeated brain MRIs are needed to detect these changes.

Its current use is limited, because the Centers for Medicare & Medicaid Services (CMS) are working on plans to provide coverage for people with Medicare participating in CMS-approved randomized controlled trials.

Lecanemab

Another Alzheimer's medicine, lecanemab, has shown promise for people with mild Alzheimer's disease and mild cognitive impairment due to Alzheimer's disease. It could become available in 2023.

A phase 3 clinical trial found the medicine slowed cognitive decline in people with early Alzheimer's disease by 27%. Lecanemab works by preventing amyloid plaques in the brain from clumping. This was the largest study so far to look at whether clearing clumps of amyloid plaques from the brain can slow the disease.

Lecanemab is under review by the FDA. Another study is looking at how effective the medicine may be for people at risk of Alzheimer's disease, including people who have a close relative with the disease.

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Oct. 12, 2022 See more In-depth

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