Adverse effects associated with the use of donepezil in general practice in England

Donepezil is an acetylcholinesterase inhibitor indicated for the symptomati c treatment of mild to moderate Alzheimer's disease. It is reported to have a relatively favourable side-effect profile. We report here on a pharmacov igilance study carried out post-marketing in England. An observational coho rt study using the technique of Prescription-Event Monitoring was carried o ut. Some 1762 patients (mean age 72.9 years; 42% male) were followed up for 6 months minimum. The commonest adverse events were nausea, diarrhoea, mal aise, dizziness and insomnia. Aggression, agitation and abnormal dreams wer e uncommonly associated with the drug. There were no cardiac rhythm disturb ances or liver disorders causally associated. The commonest adverse drug re actions are already reported in the product information. Given the relative ly small size of this cohort, the signals of abnormal dreams and psychiatri c disturbance as possible adverse drug reactions need further investigation in carefully planned studies.