Donepezil

How it works

It reversibly inhibits acetylcholinesterase, increasing synaptic acetylcholine to partially compensate for the cholinergic deficit characteristic of Alzheimer's disease.

Prescribing in practice

• Its cholinergic action can cause bradycardia and heart block, so use with caution in patients with conduction abnormalities, sick sinus syndrome or those on rate-limiting drugs, and review unexplained syncope.
• Cholinergic effects may also exacerbate asthma or COPD, peptic ulcer disease and bladder outflow obstruction, and lower the seizure threshold.
• Dose-related nausea, diarrhoea, insomnia and vivid dreams are common; taking it in the morning can reduce sleep disturbance.

Monitoring

Assess cognition, function and tolerability periodically and review cardiovascular status, including pulse, particularly in those with conduction risk factors.

Counselling the patient

• Nausea and loose stools are common initially and often settle.
• Report fainting, slow heartbeat or dizziness.
• It helps symptoms rather than curing the underlying condition.

Evidence & guidelines

NICE recommends acetylcholinesterase inhibitors including donepezil for managing mild to moderate Alzheimer's disease, supported by randomised trial evidence of symptomatic benefit.