Donepezil - Use | Dose | Side Effects

This article was medically reviewed by M.Pharm, Marko Tanaskovic on August 12, 2018. To read more about an author, click here.

Donepezil is a drug from the group of acetylcholinesterase inhibitors. By inhibiting this enzyme, this drug increases levels of acetyl choline in the brain (acetyl choline is responsible for memory). Therefore, this medication is used for alleviating the symptoms of dementia in patients with Alzheimer's disease. Alzheimer's disease is a common and unfortunately incurable disease. The only thing you can do is to alleviate symptoms, such as: memory loss, confusion and behavioral changes.

The study that included 4365 patients with mild, moderate and severe dementia due to Alzheimer's disease, has shown that this drug improves cognitive function and behaviour 1

Contraindications and precautions

Donepezil is contraindicated in patients who are allergic to the Donepezil or piperidine derivatives.

In a study published in the scientific journal Drugs Aging, it was stated that this medicine rarely causes side effects and they are usually mild and don't last long.2 Most common side effects are those which occur due to the inhibition of acetylcholinesterase.

Given that there are reported cases of bleeding in the digestive tract after administration of Donepezil 3, this drug must not be used in patients who already have ulcer.

Cases of convulsions due to the application of this drug have also been reported, and this drug should not be administered in patients who suffer from epilepsy. 4

Bearing in mind that acetylcholinesterase is the enzyme that affects the heart function, Donepezil can cause bradycardia and syncope, and it must be applied very cautiously in patients who have heart disease.

Donepezil should be also applied cautiously in the following conditions:

  • If you have asthma or other chronic lung disease
  • If you have kidney problems
  • If you have liverproblems

Pregnancy and breastfeeding

Donepezil belongs to the group C which means that animal studies revealed that this drug may have a negative impact on the baby.

It is excreted in breast milk and should not be used during breastfeeding.

How to use

The starting dose is 5 mg once daily (at bedtime).

After one month, the dose may be increased up to 10 mg that should be taken each night.


If you take a dose higher than 10 mg, you may experience the following symptoms:

  • Drooling
  • Sweating
  • Bradycardia
  • Syncope
  • Unconsciousness
  • Epileptic attack


Tell your doctor if you apply any of the following medications:

  • Other drugs for treating Alzheimer's disease (e.g. galantamine)
  • Ibuprofen and diclofenac (medicines for pain and inflammation treatment)
  • Anticholinergic drugs (e.g. tolterodine, which is used for urinary incontinence treatment)
  • Antibiotics (e.g. erythromycin and rifampicin)
  • Drugs for fungal infections treatment (e.g. ketoconazole)
  • Anticonvulsants
  • Anti-arrhythmic medications
  • Anesthetics

Side effects

The most common side effects of this drug are gastrointestinal symptoms (diarrhea and nausea). Headache may also occur very often.

From other side effects, Donepezil can cause:

  • Common cold
  • Hallucinations
  • Unusual dreams
  • The unpleasant feeling in your stomach
  • Restlessness
  • Uncontrolled urination
  • Stiffness
  • Uncontrolled movements


  1. NCBI link 1
  2. NCBI link 2
  3. BMJ link 3
  4. NCBI link 4

Information on this website are provided for educational purposes only and are not intended for medical advice, diagnosis or treatment.

If you have any concerns or questions about your health, you should always consult with a physician or other health-care professional.

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