Donepezil (Aricept) explained

What Donepezil is

Donepezil is a cholinesterase inhibitor licensed for mild to moderate Alzheimer's Disease. It increases acetylcholine levels in the brain by blocking the enzyme acetylcholinesterase. Acetylcholine plays a central role in attention and memory; Alzheimer's Disease reduces it. By raising acetylcholine, Donepezil partially compensates and improves day-to-day function in about six in ten people who tolerate it.

Donepezil is taken as a tablet, available in 5 mg and 10 mg strengths, including an orodispersible form that melts on the tongue (useful when swallowing tablets is difficult).

Who Donepezil is for

NICE Technology Appraisal TA217 recommends Donepezil for adults with mild to moderate Alzheimer's Disease, including the Alzheimer's component of Mixed Alzheimer's and Vascular Dementia. It is also sometimes used cautiously in Dementia with Lewy Bodies.

Donepezil is not recommended for Mild Cognitive Impairment, for pure Vascular Dementia without an Alzheimer's component, or for Behavioural Variant Frontotemporal Dementia.

How Donepezil is prescribed

The standard titration

• Starting dose: 5 mg once daily, usually at bedtime.
• Increase after four weeks if well tolerated: 10 mg once daily.
• Maximum dose: 10 mg once daily.

Some people stay on 5 mg long term because it suits them; others tolerate the 10 mg dose easily. Your prescriber will adjust to your situation.

Before starting

An ECG is recommended before starting, to check for slow heart rate (bradycardia) or conduction problems. A list of current medicines is reviewed for interactions, and any history of asthma, peptic ulcer or seizures is taken into account.

What to expect in the first weeks

The most common early side effects are gastrointestinal: nausea, occasional vomiting, loose stools or diarrhoea, and reduced appetite. These typically settle within one to two weeks. Taking the dose with the evening meal can help, as can adequate hydration.

Vivid dreams or sleep disturbance occur in a minority. If these are bothersome, moving the dose to the morning often helps.

Benefit, if it occurs, is usually noticeable after six to twelve weeks of the 10 mg dose. Common observations from families include clearer conversation, better engagement with familiar tasks, and reduced apathy. The improvement is often modest but meaningful.

Common side effects to watch for

Anyone with significant new chest pain, fainting, very slow pulse, or seizure-like activity should seek urgent advice (NHS 111 or 999).

Drug interactions

Donepezil is generally well behaved. Specific interactions to be aware of include:

• Other medicines that slow the heart rate (some beta blockers, Digoxin, Verapamil, Diltiazem) may add to bradycardic effects.
• Anticholinergic medicines (some bladder, gastrointestinal, sleep and antidepressant medicines) counter the action of Donepezil and may worsen cognition. A GP-led medication review is often valuable.
• Non-steroidal anti-inflammatory drugs (NSAIDs) can increase the risk of gastric irritation when combined with Donepezil.

Your pharmacist is a good first port of call for interaction checks, particularly when over-the-counter medicines are added.

Monitoring and review

A three-month review is standard after dose escalation, with a six- to twelve-month follow-up thereafter. The review looks at:

• Tolerability and side effects;
• Symptomatic response (family feedback, repeat cognitive testing such as ACE-III);
• Pulse and blood pressure;
• Whether to continue, switch (for example to Rivastigmine patch), or add Memantine.

Many people remain on Donepezil for years. There is no fixed cut-off when the medicine "stops working"; the question to ask at each review is whether the benefit, however modest, is still worth the side effect profile.

Stopping Donepezil

Some people stop Donepezil because of side effects, change of formulation, or progression to severe dementia. Sudden withdrawal can occasionally produce a measurable step-down in function over a few weeks. A planned, supervised taper is preferred.

Generic Donepezil and brand names

Donepezil is now generic and inexpensive. Brand names include Aricept and Aricept Evess (orodispersible). Different brands contain the same active ingredient and are interchangeable; the orodispersible form is useful when swallowing tablets is difficult.

Donepezil and driving

The medicine itself does not prevent driving. However, the underlying dementia diagnosis must be reported to the DVLA. The DVLA decides on a case-by-case basis after medical input and, where indicated, a practical driving assessment. See our driving and DVLA page.

Considering a private assessment?

If you would like to be assessed for a possible dementia diagnosis, or to discuss whether Donepezil or another treatment is appropriate, The Dementia Service offers virtual private memory assessments, ECG, structured reporting and shared-care prescribing with your GP.