In the U.S.—

Another commonly used name is E2020.

• Dementia symptoms treatment adjunct

Donepezil (doe-NEP-ah-zil) is used to treat the symptoms of mild to moderate Alzheimer's disease. Donepezil will not cure Alzheimer's disease, and it will not stop the disease from getting worse. However, it can improve thinking ability in some patients.

This medicine is available only with your doctor's prescription, in the following dosage form:

Oral
• Tablets (U.S. and Canada)

In deciding to use a medicine, the risks of taking the medicine must be weighed against the good it will do. This is a decision you and your doctor will make. For donepezil, the following should be considered:

Allergies—Tell your doctor if you have ever had any unusual or allergic reaction to donepezil, or to biperiden (e.g., Akineton), bupivacaine (e.g., Marcaine), methylphenidate (e.g., Ritalin), paroxetine (e.g., Paxil), rifabutin (e.g., Mycobutin), or trihexyphenidyl (e.g., Artane). Also tell your health care professional if you are allergic to any other substances, such as foods, preservatives, or dyes.

Pregnancy—Studies have not been done in pregnant women. However, studies in pregnant animals have shown that donepezil may cause unwanted effects on the offspring when the mother is given doses many times higher than the human dose. Before taking this medicine, make sure your doctor knows if you are pregnant or if you may become pregnant.

Breast-feeding—It is not known whether donepezil passes into breast milk. Because of the possibility of serious unwanted effects in the nursing infant, it is important that you discuss the use of this medicine with your doctor if you wish to breast-feed.

Children—Studies on this medicine have been done only in adult patients, and there is no specific information comparing use of donepezil in children with use in other age groups.

Older adults—In studies done to date that have included older adults, some side effects of donepezil have been shown to occur more frequently in older people than in younger adults.

Other medicines—Although certain medicines should not be used together at all, in other cases two different medicines may be used together even if an interaction might occur. In these cases, your doctor may want to change the dose, or other precautions may be necessary. When you are taking donepezil, it is especially important that your health care professional know if you are taking any other prescription or nonprescription (over-the-counter [OTC]) medicines.

• Asthma or
• Lung disease or
• Peptic ulcers, or history of or
• Seizures, or history of or
• Urinary tract blockage—Donepezil may make these conditions worse

• Heart problems—Donepezil may have unwanted effects on heart rate

• Liver problems—Higher blood levels of donepezil may result and increase the chance of side effects

Take this medicine exactly as directed by your doctor in order to improve your condition as much as possible. Do not take more of it or less of it, and do not take it more or less often than your doctor ordered.

Donepezil should be taken at bedtime unless otherwise directed by your doctor. It may be taken with or without food, on a full or empty stomach.

Dosing—

The dose of donepezil will be different for different patients. Follow your doctor's orders or the directions on the label. The following information includes only the average doses of donepezil. If your dose is different, do not change it unless your doctor tells you to do so.

The number of tablets that you take depends on the strength of the medicine.

• For oral dosage form (tablets):
  • For Alzheimer's disease:
    • Adults—5 milligrams (mg) taken at bedtime. Your doctor may increase your dose as needed. However, the dose usually is not more than 10 mg a day.
    • Children—Use and dose must be determined by your doctor.

Missed dose—

If you miss a dose of this medicine, skip the missed dose and go back to your regular dosing schedule. Do not double doses.

Storage—

To store this medicine:

• Keep out of the reach of children.
• Store away from heat and direct light.
• Do not store in the bathroom, near the kitchen sink, or in other damp places. Heat or moisture may cause the medicine to break down.
• Keep the medicine from freezing. Do not refrigerate.
• Do not keep outdated medicine or medicine no longer needed. Be sure that any discarded medicine is out of the reach of children.

It is important that your doctor check your progress at regular visits. This is necessary to allow dose adjustments and to reduce any unwanted effects.

Before you have any kind of surgery, dental treatment, or emergency treatment, tell the medical doctor or dentist in charge that you are using this medicine. Taking donepezil together with certain medicines that are used during surgery or dental or emergency treatments may increase the effects of those medicines and cause unwanted effects.

This medicine may cause some people to become dizzy or drowsy, to have blurred vision, or to have problems with clumsiness or unsteadiness. Make sure you know how you react to this medicine before you drive, use machines, or do anything else that could be dangerous if you are not alert, well-coordinated, and able to see clearly.

If you think that you or someone else may have taken an overdose of this medicine, get emergency help at once. Taking an overdose of this medicine may cause convulsions (seizures) or serious effects on your heart and your breathing. Signs of overdose include increased watering of mouth, increased sweating, low blood pressure, muscle weakness, severe nausea, severe vomiting, slow heartbeat, and troubled breathing.

Along with its needed effects, a medicine may cause some unwanted effects. Although not all of these side effects may occur, if they do occur they may need medical attention.

Check with your doctor as soon as possible if any of the following side effects occur:

• More common
  • Diarrhea;  loss of appetite;  muscle cramps;  nausea;  trouble in sleeping;  unusual tiredness or weakness;  vomiting 
  
  

• Less common
  • Abnormal dreams;  constipation;  dizziness;  drowsiness;  fainting;  frequent urination;  headache;  joint pain, stiffness, or swelling;  mental depression;  pain;  unusual bleeding or bruising;  weight loss 
  
  

• Rare
  • Black, tarry stools;  bloating;  bloody or cloudy urine;  blurred vision ;  burning, prickling, or tingling sensations;  cataract;  chills;  clumsiness or unsteadiness;  confusion;  cough;  decreased urination;  difficult or painful urination;  dryness of mouth;  eye irritation;  fever;  flushing of skin;  frequent urge to urinate;  high or low blood pressure ;  hives;  hot flashes;  increased heart rate and breathing;  increase in sexual desire or performance;  increased sweating;  increased urge to urinate during the night ;  irregular heartbeat;  itching;  loss of bladder control;  loss of bowel control;  mood or mental changes, including abnormal crying, aggression, agitation, delusions, irritability, nervousness, or restlessness;  nasal congestion;  pain in chest, upper stomach, or throat;  problems with speech;  runny nose;  severe thirst;  shortness of breath;  sneezing;  sore throat;  sunken eyes;  tightness in chest;  tremor;  troubled breathing;  wheezing;  wrinkled skin 
  
  

• Symptoms of overdose
  • Convulsions (seizures);  increased sweating ;  increased watering of mouth;  increasing muscle weakness;  low blood pressure;  severe nausea;  severe vomiting;  slow heartbeat;  troubled breathing 
  
  

Other side effects not listed above may also occur in some patients. If you notice any other effects, check with your doctor.