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Alzheimer's Disease Drugs Fact Sheet
Five prescription drugs currently are approved by the U.S. Food and Drug
Administration to treat people who have been diagnosed with Alzheimer's
disease (AD). Treating the symptoms of AD 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 Drugs stops the disease itself.
Treatment for Mild to Moderate AD
Four of these Drugs are called cholinesterase inhibitors. These drugs are
prescribed for the treatment of mild to moderate AD. They may help delay or
prevent symptoms from becoming worse for a limited time and may help control
some behavioral symptoms. The Drugs are: Razadyne® (formerly known as
Reminyl®) (galantamine), Exelon® (rivastigmine), Aricept® (donepezil), and
Cognex® (tacrine). Scientists do not yet fully understand how cholinesterase
inhibitors work to treat AD, but current research indicates that they
prevent the breakdown of acetylcholine, a brain chemical believed to be
important for memory and thinking. As AD progresses, the brain produces less
and less acetylcholine; therefore, cholinesterase inhibitors may eventually
lose their effect.
No published study directly compares these drugs. Because all four work
in a similar way, it is not expected that switching from one of these drugs
to another will produce significantly different results. However, an AD
patient may respond better to one drug than another. Cognex® (tacrine) is no
longer actively marketed by the manufacturer.
Treatment for Moderate to Severe AD
The fifth approved medication, known as Namenda® (memantine), is an
N-methyl D-aspartate (NMDA) antagonist. It is prescribed for the treatment
of moderate to severe AD. Studies have shown that the main effect of
Namenda® is to delay progression of some of the symptoms of moderate to
severe AD. The medication may allow patients to maintain certain daily
functions a little longer. For example, Namenda® may help a patient in the
later stages of AD maintain his or her ability to go to the bathroom
independently for several more months, a benefit for both patients and
caregivers.
Namenda® is believed to work by regulating glutamate, another important
brain chemical that, when produced in excessive amounts, 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.
Dosage and Side Effects
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 inhibitor Drugs. However, the higher the dose, the more
likely are side effects. The recommended effective dosage of Namenda® is 20
mg/day after the patient has successfully tolerated lower doses. Some
additional differences among these Drugs are summarized in the table on the
other side.
Patients may be drug sensitive in other ways, and they 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 Drugs.
For More Information
To learn about support groups, services, research centers, and
publications about AD, contact the following groups:
Alzheimer's Association
225 N. Michigan Avenue, Suite 1700
Chicago, IL 60601
1-800-272-3900
Website: www.alz.org
This non-profit association supports families and caregivers of patients
with AD. Nationwide chapters provide referrals to local resources.
Alzheimer's Disease Education and Referral (ADEAR) Center
PO Box 8250
Silver Spring, MD 20907-8250
1-800-438-4380
Website:
www.alzheimers.org
This service of the National Institute on Aging offers information and
publications on diagnosis, treatment, patient care, caregiver needs,
long-term care, and research related to AD.
U.S DEPARTMENT OF HEALTH AND HUMAN SERVICES
Public Health Service
National Institutes of Health
National Institute on Aging
NIH Publication No. 03-3431
January 2004
Note: The brief summary provided below 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 Drugs or supplements. Drugs
are listed in order, as approved by the U.S. Food and Drug Administration,
starting with the most recent.
DRUG NAME
|
DRUG TYPE AND TREATMENT
|
MANUFACTURER’S RECOMMENDED DOSAGE
|
COMMON SIDE EFFECTS
|
POSSIBLE DRUG INTERACTIONS
|
Namenda® (memantine)
Blocks the toxic effects associated with excess glutamate and regulates
glutamate activation. |
N-methyl D-aspartate (NMDA) antagonist
prescribed to treat symptoms of moderate to severe AD |
- 5 mg, once a day, available in tablet form
- Increase to 10 mg/day (5 mg twice a day), 15 mg/day (5 mg and 10
mg as separate doses), and 20 mg/day (10 mg twice a day) at minimum
of one week intervals if well tolerated.
|
Dizziness, headache,
constipation, confusion |
Other NMDA antagonist Drugs,
including amantadine, an antiviral used to treat the flu,
dextromethorphan, prescribed to relieve coughs due to colds or flu, and
ketamine, sometimes used as an anesthetic, have not been systematically
evaluated and should be used with caution in combination with this
medication. |
| Razadyne® (formerly known as
Reminyl®) (galantamine)
Prevents the breakdown of acetylcholine and stimulates nicotinic
receptors to release more acetylcholine in the brain. |
Cholinesterase inhibitor prescribed to
treat symptoms of mild to moderate AD |
- 4mg, twice a day (8mg/day, available in tablet or capsule form
- Increase by 8mg/day after 4 weeks to 8mg, twice a day
(16mg/day)if well tolerated.
- After another 4 weeks, increase to 12mg, twice a day (24mg/day)
if well tolerated.
|
Nausea, vomiting, diarrhea,
weight loss |
Some antidepressants such as
paroxetine, amitriptyline, fluoxetine, fluvoxamine, and other drugs with
anticholinergic action may cause retention of excess Razadyne® (formerly
known as Reminyl®) in the body, leading to complications; NSAIDs should
be used with caution in combination with this medication.* |
| Exelon® (rivastigmine)
Prevents the breakdown of acetylcholine and butyrylcholine (a brain
chemical similar to acetylcholine) in the brain. |
Cholinesterase inhibitor prescribed to
treat symptoms of mild to moderate AD |
- 1.5mg, twice a day (3mg/day, available in capsule and liquid
form
- Increase by 3mg/day every 2 weeks to 6mg, twice a day (12mg/day)
if well tolerated.
|
Nausea, vomiting, weight loss,
upset stomach, muscle weakness |
None observed in laboratory
studies; NSAIDs should be used with caution in combination with this
medication.* |
Aricept® (donepezil)
Prevents the breakdown of acetylcholine in the brain.
|
Cholinesterase inhibitor prescribed to
treat symptoms of mild to moderate AD |
- 5mg, once a day, available in tablet form
- Increase after 4-6 weeks to 10mg, once a day if well tolerated.
|
Nausea, diarrhea, vomiting
|
None observed in laboratory
studies; NSAIDs should be used with caution in combination with this
medication.* |
Cognex® (tacrine)
Prevents the breakdown of acetylcholine in the brain.
Note: Cognex is still available but no longer actively
marketed by the manufacturer.
|
Cholinesterase inhibitor prescribed to
treat symptoms of mild to moderate AD |
- 10mg, four times a day (40mg/day), in capsule form
- Increase by 40mg/day every 4 weeks to 40mg, four times a day
(160mg/day), if liver enzyme functions remain normal and if well
tolerated.
|
Nausea, diarrhea, possible
liver damage |
NSAIDs should be used with
caution in combination with this medication.* |
* Use of cholinesterase inhibitors can increase risk of stomach ulcers,
and because prolonged use of non-steroidal anti-inflammatory drugs (NSAIDs)
such as aspirin or ibuprofen can also cause stomach ulcers, NSAIDs should be
used with caution in combination with these Drugs.
U.S. DEPARTMENT OF HEALTH AND HUMAN SERVICES
Public Health Service
National Institutes of Health
National Institute on Aging
Published in December 2005
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