Donepezil

Original article by Khaleel Loonat | Last updated on 23/1/2016
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Introduction

The introduction of Acetylcholinesterase inhibitors (AChEI) in 1997 had a great impact in the management of Alzheimer's disease (AD), (Birks, 2006). AChEI are usually considered first line pharmacotherapy for mild-moderate AD and donepezil is often the first drug of choice, due to its cost effectiveness.

Mechanism of Action

  • Reversible and a non-competitive inhibitor of Acetylcholinesterase (AChE)
  • Prevents the breakdown of acetylcholine (Ach), (Ach degraded down to acetate and choline by AChE) within the synapses of the brain
  • Increasing the Ach concentration within the brain

 
Cholinergic Hypothesis- States that AD is caused by a reduction of the neurotransmitter Ach.
 

Indications and dose

Mild-moderate AD

  • Oral administration
  • Initially 5mg OD
  • Increase dose to 10mg OD if necessary
  • Doses should be given at bedtime

 

Cautions

  • Asthma, COPD
  • Sick sinus syndrome
  • Supraventricular conduction abnormalities
  • Patients who are susceptible to peptic ulcers

 

Side effects

Common or very common

Abnormal dreams, aggression, agitation, anorexia, diarrhoea, dizziness, fatigue, hallucinations, headache, insomnia, muscle cramp, nausea, pruritus, rash, syncope, urinary incontinence, vomiting. (BNF, 2015)
 

Side effects, further information

AChEI can cause unwanted cholinergic effects and therefore should be started at the lowest dose possible. The dose should be increased according to the patient’s response and tolerability.