Donepezil is used to treat dementia (a brain disorder that affects the ability to remember, think clearly, communicate, and perform daily activities and may cause changes in mood and personality) in people who have Alzheimer's disease (AD; a brain disease that slowly destroys the memory and the ability to think, learn, communicate and handle daily activities). Donepezil is in a class of medications called cholinesterase inhibitors. It improves mental function (such as memory, attention, the ability to interact with others, speak, think clearly, and perform regular daily activities) by increasing the amount of a certain naturally occurring substance in the brain. Donepezil may improve the ability to think and remember or slow the loss of these abilities in people who have AD. However, donepezil will not cure AD or prevent the loss of mental abilities at some time in the future.

Donepezil comes as a tablet and an orally disintegrating tablet (tablet that dissolves quickly in the mouth) to take by mouth. It is usually taken once a day with or without food, in the evening just before bedtime. Take donepezil at around the same time every day. Follow the directions on your prescription label carefully, and ask your doctor or pharmacist to explain any part you do not understand. Take donepezil exactly as directed. Do not take more or less of it or take it more often than prescribed by your doctor.

Donepezil helps control the symptoms of Alzheimer's disease but does not cure it. Continue to take donepezil even if you feel well. Do not stop taking donepezil without talking to your doctor.

Your doctor may start you on a low dose of donepezil and increase your dose after 4 to 6 weeks. Your doctor may increase your dose again 3 or more months later.

Swallow the 23-mg tablet whole; do not split, crush or chew it. Tell your doctor if you are unable to swallow the tablet whole.

To take the orally disintegrating tablet, place the tablet on your tongue and wait for it to dissolve. Drink some water after the tablet dissolves.

Ask your pharmacist or doctor for a copy of the manufacturer's information for the patient.

This medication may be prescribed for other uses; ask your doctor or pharmacist for more information.

Before taking donepezil,

• tell your doctor and pharmacist if you are allergic to donepezil, any piperidine medications, any other medications, any of the ingredients in donepezil tablets or orally disintegrating tablets. Ask your doctor or pharmacist if you do not know if a medication that you are allergic to is a piperidine medication. Ask your pharmacist or check the manufacturer's patient information for a list of the ingredients.
• tell your doctor and pharmacist what prescription and nonprescription medications, vitamins, nutritional supplements, and herbal products you are taking or plan to take. Be sure to mention any of the following: antihistamines; aspirin and other nonsteroidal anti-inflammatory drugs (NSAIDs) such as ibuprofen (Advil, Motrin) and naproxen (Aleve, Naprosyn); bethanechol (Duvoid, Urecholine); carbamazepine (Tegretol); dexamethasone (Decadron, Dexone); ipratropium (Atrovent); ketoconazole (Nizoral); medications for glaucoma, irritable bowel disease, motion sickness, myasthenia gravis, Parkinson's disease, ulcers, or urinary problems; phenobarbital (Luminal, Solfoton); phenytoin (Dilantin); quinidine (Quinidex); and rifampin (Rifadin, Rimactane). Your doctor may need to change the doses of your medications or monitor you carefully for side effects.
• tell your doctor if you weigh less than 120 lb (55 kg) and if you have or have ever had bleeding in your stomach or intestines; an ulcer; irregular, slow, or fast heartbeat, seizures; difficulty urinating; asthma;chronic obstructive pulmonary disease (a group of lung disease including chronic bronchitis or emphysema); or kidney, liver, or heart disease.
• tell your doctor if you are pregnant, plan to become pregnant, or are breast-feeding. If you become pregnant while taking donepezil, call your doctor.
• if you are having surgery, including dental surgery, tell the doctor or dentist that you are taking donepezil.

Donepezil may cause side effects. Tell your doctor if any of these symptoms are severe or do not go away:

• nausea
• vomiting
• diarrhea
• loss of appetite
• weight loss
• frequent urination
• difficulty controlling urination
• muscle cramps
• joint pain, swelling, or stiffness
• pain
• excessive tiredness
• difficulty falling asleep or staying asleep
• headache
• dizziness
• nervousness
• depression
• confusion
• changes in behavior or mood
• hallucinations (seeing things or hearing voices that do not exist)
• abnormal dreams
• red, scaling, itchy skin

Some side effects can be serious. If you experience any of these symptoms, call your doctor immediately or get emergency medical treatment:

• fainting
• slow heartbeat
• chest pain
• new or worsening breathing problems
• new or worsening stomach pain or heartburn
• black or tarry stools
• red blood in stools
• bloody vomit
• vomit that looks like coffee grounds
• difficulty urinating or pain when urinating
• lower back pain
• fever
• seizures
• discoloration or bruising of the skin

Donepezil may cause other side effects. Call your doctor if you have any unusual problems while you are taking this medication.