Alzheimer's: Drugs help manage symptoms

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

Alzheimer's disease is a daunting diagnosis. But working closely with your health care team to find the best strategies to manage your symptoms can help you cope and make life better.

Alzheimer's drugs offer one strategy to help manage memory loss, thinking and reasoning problems, and day-to-day function. Unfortunately, Alzheimer's drugs don't work for everyone, and they can't cure the disease or stop its progression. Over time, their effects wear off.

Research into more-effective Alzheimer's drugs is ongoing. But even if researchers discover better drugs, it will always be important to build a health care team that helps you explore all your treatment options. That may involve taking medication, tapping into your support network, and accessing community resources and services.

Role of current Alzheimer's drugs

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

  • Cholinesterase inhibitors
  • Memantine

These drugs:

  • Work in two different brain chemical messaging systems. Because of this, doctors sometimes prescribe both types at the same time. More research is needed, though, to understand how great the benefit might be from taking both categories of drugs together. Future drugs may target the disease through other strategies.
  • Are approved for specific Alzheimer's stages. These stages — mild, moderate and severe — are based on scores on mental-function tests that assess memory, awareness of time and place, and thinking and reasoning.

    Doctors may, however, prescribe Alzheimer's drugs for stages other than those for which the FDA has approved them. Doctors do this because Alzheimer's stages are not exact, individual responses to drugs may vary, and current 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, may sometimes 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. Clinical trials testing whether Alzheimer's drugs might prevent progression of MCI to Alzheimer's have generally shown no benefit.

Cholinesterase inhibitors

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

Cholinesterase inhibitors can't reverse Alzheimer's disease, and they don't stop the underlying destruction of nerve cells. Because dwindling brain cells produce less acetylcholine as the disease progresses, these medications eventually lose effectiveness.

In clinical studies, all cholinesterase inhibitors, on average, work about equally well. But in individuals, one cholinesterase inhibitor may work better or produce fewer side effects than does another. 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 may help minimize side effects.

Three cholinesterase inhibitors are commonly prescribed:

  • Donepezil (Aricept) is the only Alzheimer's drug approved to treat all stages of the disease. It's taken once a day as a pill. It's usually well tolerated, although the highest dose — a 23-milligram tablet — causes more-frequent side effects than do lower doses. In one study, donepezil appeared to temporarily postpone development of Alzheimer's in some people with mild cognitive impairment (MCI).
  • Galantamine (Razadyne) is approved to treat mild to moderate Alzheimer's. It's taken as a pill or syrup. Galantamine generally isn't recommended to treat MCI, because a large study showed volunteers with MCI who took galantamine had a significantly higher death rate than did those receiving a look-alike, inactive treatment (placebo). That study also showed galantamine didn't help prevent progression of MCI to Alzheimer's disease.
  • Rivastigmine (Exelon) is approved for mild to moderate Alzheimer's disease. It's taken as a pill or syrup. It's also available as a drug-releasing skin patch. Rivastigmine has not been shown to help prevent progression of MCI.
Aug. 18, 2011 See more In-depth