Pimavanserin is an antipsychotic which alleviates symptoms such as paranoia or delusions and works by blocking a very specific nerve receptor in the brain.
Crucially it does not produce the side effects associated with similar drugs which sedate patients and can increase the speed of deterioration in brain function.
Their use leads to 1,660 unnecessary strokes and 1,800 unnecessary deaths in the UK every year.
Reseachers at the University of Exeter Medical School tested pimavanserin in a placebo-controlled trial of 180 patients with Alzheimer’s disease psychosis to study its efficacy and safety.
Ninety of them were given pimavanserin and 90 of them a placebo.
Professor Clive Ballard, who led the research, said: “Psychosis is a particularly terrifying symptom of Alzheimer’s disease.
“People may experience paranoia, or see, hear or smell things that are not there. It’s distressing both for those experiencing the delusions and for their carers.
“It’s particularly encouraging that most benefit was seen in those with the most severe psychotic symptom, as this group is most likely to be prescribed antipsychotics.
“We are talking about vulnerable elderly, frail people who are suffering terrifying symptoms, being sedated with current antipsychotics even though its well known that they cause terrible health issues and even death in people with dementia and have very little benefit.
Pimavanserin’s ability to reduce psychotic symptoms in dementia is now being assessed in a larger-scale clinical trial in the US.
As many as 22 million people worldwide who are living with Alzheimer’s disease will experience psychotic episodes.