(NIA) Several prescription drugs are currently approved by the U.S. Food and Drug Administration (FDA) to treat people who have been diagnosed with Alzheimer’s disease. Treating the symptoms of Alzheimer’s can provide patients with comfort, dignity, and independence for a longer period of time and can encourage and assist their caregivers as well.
It is important to understand that none of these medications stops the disease itself.
Medications called cholinesterase inhibitors are prescribed for mild to moderate Alzheimer’s disease. These drugs may help delay or prevent symptoms from becoming worse for a limited time and may help control some behavioral symptoms. The medications include: Razadyne® (galantamine), Exelon® (rivastigmine), and Aricept® (donepezil).
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; therefore, cholinesterase inhibitors may eventually lose their effect.
No published study directly compares these drugs. Because they work in a similar way, switching from one of these drugs to another probably will not produce significantly different results. However, an Alzheimer’s patient may respond better to one drug than another.
A medication known as Namenda® (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 delay progression of some of the symptoms of moderate to severe Alzheimer’s. It may allow patients to maintain certain daily functions a little longer than they would without the medication. For example, Namenda® may help a patient 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 patients and caregivers.
The FDA has also approved Aricept® and Namzaric®, a combination of Namenda® and donepezil, for the treatment of moderate to severe Alzheimer’s disease.
Namenda® 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 very differently from cholinesterase inhibitors, the two types of drugs can be prescribed in combination.
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 patients may benefit from higher doses of the cholinesterase inhibitors. However, the higher the dose, the more likely are side effects. The recommended effective dosages of drugs prescribed to treat the symptoms of Alzheimer’s and the drugs’ possible side effects are summarized in the table below.
Patients should be monitored when a drug is started. 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.
|Clinical trials are the best way to find out if promising new treatments are safe and effective in humans. Volunteer participants are needed for many Alzheimer’s trials conducted around the United States. To learn more, talk with your doctor or visit the ADEAR Center’s listing of clinical trials at www.nia.nih.gov/Alzheimers/ResearchInformation/ClinicalTrials. More information is available at www.ClinicalTrials.gov.|
For More Information
To learn about support groups, research centers, research studies, and publications about Alzheimer’s disease, contact the following resources:
Alzheimer’s Disease Education and Referral (ADEAR) Center
The National Institute on Aging’s ADEAR Center offers information and publications for families, caregivers, and professionals on diagnosis, treatment, patient care, caregiver needs, long-term care, education, training, and research related to Alzheimer’s disease. Staff members answer telephone, email, and written requests and make referrals to local and national resources. Visit the ADEAR website to learn more about Alzheimer’s and other dementias, find clinical trials, and sign up for email updates.
Alzheimer’s Foundation of America
Medications to Treat Alzheimer’s Disease
Note: This brief summary does not include all information important for patient use and should not be used as a substitute for professional medical advice. Consult the prescribing doctor and read the package insert before using these or any other medications or supplements. Drugs are listed in order of FDA approval, starting with the most recent.
|DRUG NAME||DRUG TYPE AND USE||HOW IT WORKS||COMMON SIDE EFFECTS|
|Namenda® (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, constipation, confusion|
|Razadyne® (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, weight loss, loss of appetite|
||Cholinesterase inhibitor prescribed to treat symptoms of mild to moderate Alzheimer’s||Prevents the breakdown of acetylcholine and butyrylcholine (a brain chemical similar to acetylcholine) in the brain||Nausea, vomiting, diarrhea, weight loss, loss of appetite, muscle weakness|
||Cholinesterase inhibitor prescribed to treat symptoms of mild to moderate, and moderate to severe Alzheimer’s||Prevents the breakdown of acetylcholine in the brain||Nausea, vomiting, diarrhea|
Manufacturer’s Recommended Dosage to Treat Alzheimer’s Disease
MANUFACTURER’S RECOMMENDED DOSAGE
FOR MORE INFORMATION
||For current information about this drug’s safety and use, visit www.namenda.com. Click on “Prescribing Information” to see the drug label.|
||For current information about this drug’s safety and use, visit www.razadyneer.com. Click on “Important Safety Information” to see links to prescribing information.|
||For current information about this drug’s safety and use, visit www.fda.gov/cder. Click on “Drugs@FDA,” search for Exelon, and click on drug-name links to see “Label Information.”|
||For current information about this drug’s safety and use, visit www.fda.gov/cder. Click on “Drugs@FDA,” search for Aricept, and click on drug-name links to see “Label Information.”|
*Available as a generic drug.
National Institute on Aging