Withdrawing a commonly-prescribed Alzheimer’s disease drug from people in the advanced stages of the disease doubles their risk of being placed in a nursing home within a year, according to research published today in The Lancet Neurology.

Researchers funded by the Medical Research Council and Alzheimer’s Society followed 295 people with moderate to severe Alzheimer’s disease to monitor the effects of continuing or discontinuing the drug donepezil – which is typically withdrawn in the later stages of the disease because of a lack of perceived benefit by clinicians. The participants were randomly selected to either continue donepezil or withdraw from the drug by receiving a placebo. These two groups were then each divided to test the effect of receiving another dementia drug, memantine, or a placebo.

The DOMINO trial, conducted by scientists at University College London (UCL), found that withdrawing donepezil doubled the risk of nursing home placement after a year. Memantine was not found to have any effect on risk of nursing home placement.

In the UK, 70% of care home residents have dementia or severe memory problems. The costs of residential care vary across the country, but the average cost is estimated to be between £30,732 and £34,424 per year, for people with dementia. By comparison, the cost of donepezil is around £21.59 per year.

Robert Howard, professor of old age psychiatry at UCL, said: “Our previous work showed that, even when patients had progressed to the moderate or severe stages of their dementia, continuing with donezepil treatment provided modest benefits in cognitive function and in how well people could perform their daily activities.

“Our new results show that these benefits translate into a delay in becoming dependant on residential care, a point that many of us dread. We are all impatient for the advent of true disease-modifying drugs that can slow or halt the Alzheimer process, but donepezil is available right now and at modest cost.”

Dr Kathryn Adcock, head of neurosciences and mental health at the Medical Research Council, said: “This study provides strong evidence that donepezil can benefit people in the more severe stages of Alzheimer’s disease for longer than was expected.  The number of people with dementia is at a critical level and it’s never been more important to invest in research to help doctors make informed decisions about treatments for their patients.

“We currently have no cure for dementia but we are closing the gap and in the meantime, we are committed to developing effective and safe treatments to improve the quality of life for people with Alzheimer’s disease and their care givers.”

Dr Doug Brown, director of research and development at the Alzheimer’s Society, said: “With no new treatments for Alzheimer’s disease in over a decade, it is absolutely crucial that we make the most of the drugs we have available. Residential care can be the best option for someone whose care needs are complex, but it is important that we continue to find better ways to support people with dementia to remain in their own homes for longer.

“These robust findings are of real significance to people with dementia and their families who want to continue living at home for as long as possible. We urge clinicians to consider the implications of this research and adjust their prescribing patterns accordingly.”

In 2001, NICE approved the use of three anticholinesterase inhibitors – which included donepezil – in the early and moderate stages of Alzheimer’s. The drugs had been found to reduce the symptoms of Alzheimer’s and were the first treatments to be approved for the disease.

Previous results published from the DOMINO trial in 2012 were the first to show that continued treatment with donepezil can provide cognitive and functional benefits in people with moderate to severe Alzheimer’s disease, such as retaining the ability to eat, dress and go shopping more independently. A later survey found that two-thirds of old age psychiatrists felt that prescribing practice would change based on the results of this trial.

In the UK, it is estimated that 527,000 people are living with Alzheimer’s disease, the most common form of dementia. An estimated 58,600 people with mild-to-moderate Alzheimer’s disease are currently taking donepezil.