How Is Alzheimer's Disease Treated?
Alzheimer’s disease is complex, and it is therefore unlikely that any one drug or other intervention will ever successfully treat it in all people living with the disease. Still, in recent years, scientists have made tremendous progress in better understanding Alzheimer’s and in developing and testing new treatments, including several medications that are in late-stage clinical trials.
Several prescription drugs are already approved by the U.S. Food and Drug Administration (FDA) to help manage symptoms in people with Alzheimer’s disease. And, on June 7, 2021, FDA provided accelerated approval for the newest medication, aducanumab, which helps to reduce amyloid deposits in the brain and may help slow the progression of Alzheimer’s, although it has not yet been shown to affect clinical symptoms or outcomes, such as progression of cognitive decline or dementia.
Most medicines work best for people in the early or middle stages of Alzheimer’s. However, it is important to understand that none of the medications available at this time will cure Alzheimer’s.
Treatment for mild to moderate Alzheimer’s
Treating the symptoms of Alzheimer’s can provide people with comfort, dignity, and independence for a longer period of time and can encourage and assist their caregivers as well. 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.
Scientists do not yet fully understand how cholinesterase inhibitors work to treat Alzheimer’s disease, but research indicates that they prevent the breakdown of acetylcholine, a brain chemical believed to be important for memory and thinking. As Alzheimer’s progresses, the brain produces less and less acetylcholine, so these medicines may eventually lose their effect. 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.
Medications that target the underlying causes of a disease are called disease-modifying drugs or therapies. Aducanumab is the only disease-modifying medication currently approved to treat Alzheimer’s. This medication is a human antibody, or immunotherapy, that targets the protein beta-amyloid and helps to reduce amyloid plaques, which are brain lesions associated with Alzheimer’s. Clinical studies to determine the effectiveness of aducanumab were conducted only in people with early-stage Alzheimer’s or mild cognitive impairment. Researchers are continuing to study whether this medication works to affect a person’s rate of cognitive decline over time.
Before prescribing aducanumab, doctors may require PET scans or an analysis of cerebrospinal fluid to evaluate whether amyloid deposits are present in the brain. This can help doctors make an accurate diagnosis of Alzheimer’s before prescribing the medication. Once a person is on aducanumab, their doctor or specialist may require routine MRIs to monitor for side effects such as brain swelling or bleeding in the brain.
Several other disease-modifying medications are being tested in people with mild cognitive impairment or early Alzheimer’s as potential treatments.
Treatment for moderate to severe Alzheimer’s
A medication known as memantine, an N-methyl D-aspartate (NMDA) antagonist, is prescribed to treat moderate to severe Alzheimer’s disease. This drug’s main effect is 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 his or her ability to use the bathroom independently for several more months, a benefit for both the person with Alzheimer's and 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 the treatment of moderate to severe Alzheimer’s.
|Drug Name||Drug Type and Use||How It Works||Common Side Effects|
|Aducanumab||Disease-modifying immunotherapy prescribed to treat mild cognitive impairment or mild Alzheimer’s||Removes abnormal beta-amyloid to help reduce the number of plaques in the brain||Amyloid-related imaging abnormalities (ARIA), which can lead to fluid buildup or bleeding in the brain; also headache, dizziness, falls, diarrhea, confusion|
|Donepezil||Cholinesterase inhibitor prescribed to treat symptoms of mild, moderate, and severe Alzheimer's||Prevents the breakdown of acetylcholine in the brain||Nausea, vomiting, diarrhea, muscle cramps, fatigue, weight loss|
|Rivastigmine||Cholinesterase inhibitor prescribed to treat symptoms of mild, moderate, and severe Alzheimer's||Prevents the breakdown of acetylcholine and butyrylcholine (a brain chemical similar to acetylcholine) in the brain||Nausea, vomiting, diarrhea, weight loss, indigestion, muscle weakness|
|Memantine||N-methyl D-aspartate (NMDA) antagonist prescribed to treat symptoms of moderate to severe Alzheimer's||Blocks the toxic effects associated with excess glutamate and regulates glutamate activation||Dizziness, headache, diarrhea, constipation, confusion|
|Manufactured combination of memantine and donepezil||NMDA antagonist and cholinesterase inhibitor prescribed to treat symptoms of moderate to severe Alzheimer’s||Blocks the toxic effects associated with excess glutamate and prevents the breakdown of acetylcholine in the brain||Headache, nausea, vomiting, diarrhea, dizziness, anorexia|
|Galantamine||Cholinesterase inhibitor prescribed to treat symptoms of mild to moderate Alzheimer's||Prevents the breakdown of acetylcholine and stimulates nicotinic receptors to release more acetylcholine in the brain||Nausea, vomiting, diarrhea, decreased appetite, dizziness, headache|
|Drug Name||Delivery Method||For More Information|
||Prescribing information (PDF, 343K)|
||Prescribing information (PDF, 594K)|
||Prescribing information (PDF, 284K)|
||Prescribing information (PDF, 604K)|
|Manufactured combination of memantine and donepezil||
||Prescribing information (PDF, 455K)|
||Prescribing information (PDF, 1M)|
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 the drug. There is some evidence that certain people may benefit from higher doses of Alzheimer’s medications. However, the higher the dose, the more likely side effects will occur.
Patients should be monitored when a drug is started. All of these medicines have possible side effects, including nausea, vomiting, diarrhea, allergic reactions, and loss of appetite. Report any unusual symptoms to the prescribing doctor right away. It is important to follow the doctor’s instructions when taking any medication, including vitamins and herbal supplements. Also, let the doctor know before adding or changing any medications.
Managing behavioral symptoms of Alzheimer's disease
Common behavioral symptoms of Alzheimer’s include sleeplessness, wandering, agitation, anxiety, aggression, restlessness, and depression. Scientists are learning why these symptoms occur and are studying new treatments — drug and nondrug — to manage them. Research has shown that treating behavioral symptoms can make people with Alzheimer’s more comfortable and makes things easier for caregivers.
Experts agree that medicines to treat these behavior problems should be used only after other strategies that don’t use medicine have been tried. Learn more about behavioral changes in people with Alzheimer's disease and ways to cope.
Medicines to be used with caution in people with Alzheimer's disease
There are some medicines, such as sleep aids, anti-anxiety drugs, anti-convulsants, and antipsychotics, that a person with Alzheimer’s disease should take only:
- After the doctor has explained all the risks and side effects of the medicine
- After other, safer nonmedication options have not helped treat the problem
People living with Alzheimer’s and their caregivers must watch closely for side effects from these medications.
Sleep aids are used to help people get to sleep and stay asleep. People with Alzheimer’s should NOT use these drugs regularly because they make the person more confused and more likely to fall. There are lifestyle changes people can make to improve their sleep. Learn more about getting a good night's sleep.
Anti-anxiety drugs are used to treat agitation. These drugs can cause sleepiness, dizziness, falls, and confusion. For this reason, doctors recommend they should only be used for short periods of time.
Anti-convulsants are drugs sometimes used to treat severe aggression. Side effects may cause sleepiness, dizziness, mood swings, and confusion.
Antipsychotics are drugs used to treat paranoia, hallucinations, agitation, and aggression. Side effects of using these drugs can be serious, including increased risk of death in some older people with dementia. They should only be given to people with Alzheimer’s when the doctor agrees that the symptoms are severe.
The future of Alzheimer's disease treatments
Alzheimer’s disease research has developed to a point where scientists are exploring a variety of avenues to not only treat symptoms but also address underlying disease processes. In ongoing clinical trials, scientists are developing and testing several possible interventions, including immunization therapy, drug therapies, cognitive training, physical activity, and treatments for cardiovascular disease and diabetes.
For more information about treating Alzheimer's
NIA Alzheimer’s and related Dementias Education and Referral (ADEAR) Center
The NIA ADEAR Center offers information and free print publications about Alzheimer’s and related dementias for families, caregivers, and health professionals. ADEAR Center staff answer telephone, email, and written requests and make referrals to local and national resources.
Explore the Alzheimers.gov portal for information and resources on Alzheimer’s and related dementias from across the federal government.
National Library of Medicine
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.
July 08, 2021