Eisai and Pfizer’s Aricept does not ease the agitation and aggression that many patients with Alzheimer’s disease suffer from, according to a new study.

The study, published in the New England Journal of Medicine and conducted by researchers at King’s College London, involved 272 patients with significant Alzheimer's disease-related agitation who were randomised to receive 10mg daily of Aricept (donepezil) or placebo for 12 weeks. The group, most of whom were elderly women with an average age of 84 and were living in residential homes, had previously failed to show improvement in their agitation after up to four weeks of psychosocial, ie drug-free, therapy sessions.

However the results showed that around 20% of patients in each group experienced a 30% or greater improvement in their level of agitation, so donepezil was no better than placebo. The researchers, led by Robert Howard, expressed their disappointment with the findings, as cholinesterase inhibitors such as Aricept ease the cognitive effects of Alzheimer's disease and previous studies had suggested some positive behaviour changes as a secondary outcome.

This was not the case in this trial, however, although this class of medicine is often used for the purpose of reducing agitation, they are not approved by the US Food and Drug Administration and Dr Howard noted that the search for a treatment that does cut down aggressive outbursts goes on. "It is becoming increasingly clear that tranquilisers are not an adequate treatment for managing behavioural symptoms in Alzheimer's patients and their use is associated with serious potential side effects," he said. "Sadly, but importantly, our results show that while donepezil may improve memory and attention in some patients, it is not effective in the management of these distressing behaviours."