Medications and Drugs
Pharmacy Author: Emmanuel Saltiel,
Pharm. D.
Medical Editor: Jay Marks, M.D.
GENERIC NAME: donepezil
BRAND NAME: Aricept, Aricept ODT
DRUG CLASS AND MECHANISM: Donepezil is an oral medication used to treat
Alzheimer's disease. It belongs to a class of drugs called cholinesterase
inhibitors that also includes tacrine (Cognex). Scientists believe that
Alzheimer's disease may result from a deficiency in chemicals (neurotransmitters)
used by nerves in the brain to communicate with one another. Donepezil inhibits
acetylcholinesterase, an enzyme responsible for the destruction of one
neurotransmitter, acetylcholine. This leads to increased concentrations of
acetylcholine in the brain, and the increased concentrations are believed to be
responsible for the improvement seen during treatment with donepezil. Donepezil
improves the symptoms but does not slow down the progression of Alzheimer's
disease. Donepezil was approved by the FDA in 1996.
PRESCRIPTION: yes
GENERIC AVAILABLE: no
PREPARATIONS: Aricept is
available in 5 and 10 mg tablets. Aricept ODT (orally disintegrating tablets)
also are available in 5 and 10 mg tablets.
STORAGE: Tablets should be stored at room temperature, 15-30°C (59-86°F).
PRESCRIBED FOR: Donepezil is used for the treatment of mild to moderate
dementia of the Alzheimer's type.
DOSING: Donepezil is generally taken once daily at night prior to retiring.
Its absorption is not affected by food so that it may be taken with or without
food.
DRUG INTERACTIONS: Drugs with anti-cholinergic properties that can cross into
the brain, such as atropine, benztropine (Cogentin), and trihexyphenidyl
(Artane) counteract the effects of donepezil and should be avoided during
therapy with donepezil.
Donepezil is metabolized (eliminated) by enzymes in the liver. The rate of
metabolism of donepezil may be increased by medications that increase the
amounts of these enzymes, such as carbamazepine (Tegretol), dexamethasone
(Decadron), phenobarbital, phenytoin (Dilantin), and rifampin (Rifadin). By
increasing elimination, these drugs may reduce the effects of donepezil.
Ketoconazole (Nizoral) has been shown to block the enzymes in the liver that
metabolize donepezil. Therefore, concurrent use of ketoconazole and donepezil
may result in increased concentrations of donepezil in the body and possibly
lead to donepezil side effects. Quinidine (Quinidex, Quinaglute) also has been
shown to inhibit the enzymes that metabolize donepezil and may cause donepezil
side effects.
PREGNANCY: It is not known whether donepezil is harmful to the fetus. Safe
use during pregnancy has not been established.
NURSING MOTHERS: It is not known whether the donepezil is secreted into
breast milk or if breast-feeding while taking donepezil is safe for the nursing
infant.
SIDE EFFECTS: The most frequently reported side effects associated with
donepezil include headache, generalized pain, fatigue, dizziness, nausea,
vomiting, diarrhea, loss of appetite, weight loss, muscle cramping, joint pain,
insomnia, and increased frequency of urination.
Tacrine (Cognex), another anticholinesterase medication used in the treatment
of Alzheimer's disease, is associated with liver toxicity. Donepezil does not
appear to be associated with liver toxicity.
Reference: FDA Prescribing Information
Last Editorial Review: 6/2/2003
Report Problems to the Food and Drug Administration
You are encouraged to report negative side effects of prescription drugs to the FDA. Visit the FDA MedWatch website or call 1-800-FDA-1088.
- Drug Interactions - Learn about potential drug interactions you may be exposed to. Drug interactions can occur with prescription drugs, OTC medication, vitamins, herbs, and supplements.
- Alzheimer's Disease - Learn about Alzheimer's disease, a common cause of dementia. Symptoms and warning signs include: memory loss, difficulty performing familiar tasks, disorientation to time and place, misplacing things, and more.
- Drugs: What You Should Know About Your Drugs - Find out what you should know about your drugs such as side effects, warnings and precautions, storage information, and if a generic version is as good as the brand name.
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