Aricept (Donepezil)

How does it work?

Aricept tablets and Aricept Evess tablets both contain the active ingredient donepezil hydrochloride, which is a type of medicine called an acetylcholinesterase inhibitor. It works by slowing the breakdown of a compound in the brain called acetylcholine.

Acetylcholine is a natural compound known as a neurotransmitter. Neurotransmitters are stored in nerve cells in the brain and nervous system, and are involved in transmitting messages between the nerve cells. They are necessary for the normal functioning of the brain and nervous system. Acetylcholine in the brain is continually being released by nerve cells, and then broken down by another natural chemical called acetylcholinesterase.

One of the features of Alzheimer's disease appears to be a lower than normal level of acetylcholine in the brain. This is due in part to degeneration of brain cells, in particular those that normally release acetylcholine.

Donepezil increases the level of acetylcholine in the brain. It does this by preventing the action of acetylcholinesterase, the compound that normally breaks it down. This slows the breakdown of acetylcholine that is released from remaining undamaged nerve cells in the brain.

The result of this is increased activity of acetylcholine in the brain. This improves the cognitive processes of thinking, learning and memory, and improves the symptoms of dementia and daily functioning in Alzheimer's disease.

Donepezil is used to treat mild to moderately severe dementia in people with Alzheimer's disease. However, it only slows the worsening of the dementia, rather than being a cure. As a result, your doctor will want to re-assess the patient after they have been taking the medicine for two to four months at the maintenance dose. If there has been no improvement in their symptoms, or they continue to deteriorate, your doctor may decide it is not worth continuing the medicine. For patients who continue treatment, the benefit of the medicine should be reassessed on a regular basis. The medicine should be stopped when it is considered that it is no longer providing a beneficial effect.

Aricept tablets are standard tablets. Aricept Evess tablets are known as 'orodispersible tablets'. They are designed to disintegrate on the tongue in the saliva and then be swallowed either with or without a drink, as the patient prefers. These tablets may be useful for people who don't like to take or can't swallow standard tablets. Both types of tablet should be taken once a day, in the evening before going to bed.

What is it used for?

  • Mild to moderately severe Alzheimer's dementia.


  • The benefit of this medicine in treating dementia or memory loss that are due to causes other than Alzheimer's disease has not been demonstrated. It should only be used to treat dementia that has been confirmed as Alzheimer's disease by a doctor experienced in treating Alzheimer's.
  • A doctor will only prescribe this medicine if the patient has a caregiver available who will regularly make sure that the patient is taking the medicine.
  • This medicine may cause fatigue, dizziness and muscle cramps, particularly when starting treatment or increasing the dose. As a result it may reduce the patients ability to perform potentially hazardous tasks safely.

Use with caution in

  • Decreased liver function.
  • A problem common in the elderly, related to poor control of the working of the heart (sick sinus syndrome).
  • Disturbances of the heart's electrical message pathways (heart conduction defects, eg heart block).
  • History of peptic ulcer.
  • People taking long-term non-steroidal anti-inflammatory drugs (NSAIDs) eg diclofenac, indometacin.
  • History of difficulty passing urine (urinary obstruction).
  • Parkinson's disease.
  • Epilepsy.
  • Asthma.
  • Chronic obstructive pulmonary disease (COPD).

Not to be used in

  • Children.
  • Breastfeeding.
  • Aricept standard tablets contain lactose and are not suitable for people with rare hereditary problems of galactose intolerance, the Lapp lactase deficiency or glucose-galactose malabsorption.

This medicine should not be used if you are allergic to one or any of its ingredients. Please inform your doctor or pharmacist if you have previously experienced such an allergy.If you feel you have experienced an allergic reaction, stop using this medicine and inform your doctor or pharmacist immediately.

Pregnancy and breastfeeding

Certain medicines should not be used during pregnancy or breastfeeding. However, other medicines may be safely used in pregnancy or breastfeeding providing the benefits to the mother outweigh the risks to the unborn baby. Always inform your doctor if you are pregnant or planning a pregnancy, before using any medicine.

  • The safety of this medicine for use during pregnancy has not been established. It should not be used during pregnancy unless considered essential by your doctor. Seek medical advice from your doctor.
  • It is not known if this medicine passes into breast milk. It should not be used by women who are breastfeeding. Seek medical advice from your doctor.

Side effects

Medicines and their possible side effects can affect individual people in different ways. The following are some of the side effects that are known to be associated with this medicine. Because a side effect is stated here, it does not mean that all people using this medicine will experience that or any side effect.

  • Nausea and vomiting.
  • Loss of appetite.
  • Diarrhoea.
  • Fatigue.
  • Difficulty in sleeping (insomnia).
  • Headache.
  • Dizziness.
  • Fainting.
  • Hallucinations.
  • Agitation.
  • Aggressive behaviour.
  • Muscle cramps.
  • Urinary incontinence.
  • Rash or itching.
  • Ulceration or bleeding in the stomach or intestines.
  • Slow heart rate (bradycardia).
  • Seizure.
  • Liver disorders, eg hepatitis.
  • Abnormal movements of the hands, legs, face, neck and tongue, eg tremor, twitching, rigidity (extrapyramidal effects).

The side effects listed above may not include all of the side effects reported by the drug's manufacturer.For more information about any other possible risks associated with this medicine, please read the information provided with the medicine or consult your doctor or pharmacist.

How can this medicine affect other medicines?

It is important to tell your doctor or pharmacist what medicines the patient is already taking, including those bought without a prescription and herbal medicines, before they start treatment with this medicine. Similarly, check with your doctor or pharmacist before any new medicines are taken with this one, to ensure that the combination is safe.

This medicine should not be taken with other medicines that increase the activity of acetylcholine, as this may increase the risk of side effects. These medicines include the following:

  • medicines for myaesthenia gravis, eg neostigmine, edrophonium chloride, distigmine bromide, pyridostigmine bromide
  • other medicines for Alzheimer's disease, eg galantamine, rivastigmine
  • certain medicines for urinary retention, eg bethanechol chloride, distigmine
  • pilocarpine.

This medicine has an opposite effect to anticholinergic medicines, which work by decreasing the activity of acetylcholine. If taken together, anticholinergic medicines and donepezil could therefore oppose each other's effects, which could make one or both medicines less effective. As a result, anticholinergic medicines should be avoided by people taking donepezil. They include the following:

  • anticholinergic medicines for Parkinson's disease, eg procyclidine, benzatropine, orphenadrine, trihexyphenidyl
  • ipratropium bromide for asthma
  • antispasmodics for gut disorders, eg hyoscine, atropine, propantheline
  • medicines for urinary incontinence, eg oxybutinin, flavoxate, tolterodine, propiverine, trospium.

The following medicines may possibly increase the amount of donepezil in the blood:

  • erythromycin
  • fluoxetine
  • itraconazole
  • ketoconzole
  • quinidine.

The following medicines may possibly decrease the amount of donepezil in the blood:

  • carbamazepine
  • phenytoin
  • rifampicin.

Other medicines containing the same active ingredient

There are currently no other medicines available in the UK that contain donepezil as the active ingredient.