Home Medicines Donepezil: effect, areas of application, side effects

Donepezil: effect, areas of application, side effects

by Josephine Andrews
Published: Last Updated on 321 views

Donepezil is used for the symptomatic treatment of mild to moderate forms of Alzheimer’s dementia. The active ingredient improves memory and memory, but does not prevent the progression of the disease. Here you can read everything interesting about donepezil: effect, application and possible interactions and side effects.

This is how donepezil works

Donepezil is an anti-dementia drug, i.e. a remedy for dementia. The most common form of dementia is Alzheimer’s disease . This gradually causes nerve cells (neurons) to die in the brain . A large part of the nerve cells has usually already died before the first symptoms appear and the disease is discovered.

A nerve cell can release messenger substances (neurotransmitters) to communicate with other neurons. These transmit their signal by docking onto special docking sites (receptors) in the membrane of neighboring nerve cells.

Acetylcholine is one of the most important neurotransmitters involved in memory , retention and memory. It works like the other messenger substances by docking to its receptors in the membrane of other nerve cells. Thereafter, acetylcholine is split by an enzyme (acetylcholinesterase) into acetate and choline, which no longer act on the receptors, ending the signal. The two cleavage products are taken back into the first nerve cell, linked and can then be released again if necessary.

Since nerve cells not only have one-to-one connections, but one nerve cell is usually in contact with many thousands of other nerve cells, the cells in Alzheimer’s patients are only dying off when a threshold value is exceeded. The remaining cell contacts are then no longer sufficient to transmit signals – the brain can no longer compensate for the loss.

Donepezil is used as a selective inhibitor of the enzyme acetylcholinesterase to alleviate the symptoms of Alzheimer’s disease and improve memory. It therefore inhibits the enzyme so that acetylcholine remains longer on the receptors of the downstream nerve cells – its signal becomes stronger, so to speak.

Despite the loss of brain cells, the remaining nerve cells can still communicate with normal intensity, which improves the memory and memory of Alzheimer’s patients. This can be used to delay the point at which a patient requires care.

Clinical studies on donepezil use in Alzheimer’s confirm a stabilization of cognitive performance (human functions related to perception, learning, memory, thinking and knowledge) for a period of at least six months.

intake, degradation and excretion

After being taken as a tablet, donepezil enters the blood via the intestine and from there crosses the blood-brain barrier into the central nervous system. There it unfolds its effect.

In the liver, donepezil is partially metabolized to active and non-active metabolites. Most of these are excreted in the urine and to a lesser extent in the stool. About 70 hours after ingestion, half of the active ingredient has left the body again.

When is donepezil used?

Donepezil is approved for the symptomatic treatment of mild to moderate Alzheimer’s dementia.

Outside the area of ​​approval (“off-label”), it is also used as a palliative drug in severe Alzheimer’s dementia.

It must be taken continuously to maintain the effect. The effect is dose-dependent, which is why the highest tolerable dose is sought.

How Donepezil is used

The active ingredient is taken as a salt (donepezil hydrochloride) in the form of tablets or orodispersible tablets (dissolve in seconds in the mouth). Treatment usually starts with five milligrams of donepezil once a day.

After one month, the doctor assesses whether the dosage is sufficient or whether it needs to be increased to ten milligrams of donepezil per day. Higher dosages are not recommended.

Therapy should only be given if the patient is in a nursing facility or has a caregiver who will monitor the use of donepezil.

Non-drug support for the patient in the form of a regular daily routine (structuring), the involvement of relatives and paying attention to known reference persons and a familiar environment is also recommended.

What are the side effects of donepezil?

More than ten percent of those treated complain of diarrhea, nausea and headaches. These side effects mainly occur if the dose is increased too quickly.

Loss of appetite, aggressive behavior, agitation, dizziness, insomnia, vomiting, indigestion, skin rashes, muscle cramps, incontinence and tiredness often occur while taking donepezil .

Seizures, slow heartbeat and gastrointestinal bleeding may also occur as side effects in one in a hundred to a thousand patients.

What should be considered when taking donepezil?


Donepezil should not be taken if there is a known hypersensitivity to the active ingredient.


Since donepezil is broken down in the liver mainly by two different enzymes (cytochrome P450 2D6 and 3A4), which also break down other active substances, interactions can occur when these active substances are given in combination.

Examples include many antibiotics (such as erythromycin, metronidazole , chloramphenicol), HIV drugs (such as ritonavir, indinavir), the blood pressure drug verapamil, antifungal drugs (such as fluconazole, ketoconazole, itraconazole), and many herbal remedies (such as valerian , goldenseal, ginseng ) and grapefruit juice.

Some active ingredients ensure that more enzymes are formed in the liver, which then break down donepezil faster. Its effectiveness suffers as a result. This is the case, for example, with drugs used to treat convulsions and epilepsy (such as phenytoin , carbamazepine , oxcarbazepine), the anesthetic phenobarbital, and also some foods (such as ginger , garlic , liquorice).

Patients with respiratory diseases such as asthma or COPD should use donepezil with caution as the risk of acute deterioration may increase.

If non-steroidal anti-inflammatory drugs (NSAIDs such as ASA, ibuprofen , diclofenac ) are taken regularly in addition to donepezil, the risk of gastrointestinal bleeding may increase.

age restriction

Donepezil is not recommended for children and adolescents under 18 years of age. Likewise, due to lack of experience, adult patients with severe hepatic impairment should not take donepezil.

pregnancy and breast feeding period

Pregnant and breastfeeding women should not take Donepezil, as there are no studies on the safety of intake and effectiveness.

How to get medication with donepezil

Donepezil can be obtained from pharmacies in Germany, Austria and Switzerland with a doctor’s prescription.

Since when is Donepezil known?

Donepezil development began in Japan in 1983. The active ingredient was first approved in the USA in 1996. Generics with the active ingredient donepezil have been on the market since 2010.

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