A cheap off-patent drug that relieves some symptoms of Alzheimer’s disease may also help keep people at an advanced stage of the illness out of nursing homes, at least for a while.

Research showed that withdrawing the commonly-used drug donepezil in moderate-to-severe patients doubled their risk of moving into nursing care within a year, although it made no difference during the following three years.

Donepezil, originally sold by Eisai and Pfizer as Aricept and now available generically for just over £20 a year, works by raising the levels of chemicals within the brain that allow nerve cells to communicate. Like other existing Alzheimer’s treatments, it cannot slow the disease process itself.

It is currently only approved for mild-to-moderate disease, so patients often stop taking it when they deteriorate. But Robert Howard of University College London, who led a publicly-funded study of the drug, said it was time to reconsider this.

We are all impatient for the advent of true disease-modifying drugs that can slow or halt the Alzheimer’s process

“People will look at our trial and it will make them think that these drugs have more to offer in severe Alzheimer’s disease than perhaps was previously thought,” he told reporters.

The new study is important, he believes, because it shows how a drug could change lives by keeping sufferers at home, thereby saving on residential dementia care that costs more than £30,000 a year.

“We are all impatient for the advent of true disease-modifying drugs that can slow or halt the Alzheimer’s process, but donepezil is available right now and at modest cost,” Howard said.

The new findings, published in the journal Lancet Neuro-logy, are a follow-up of trial data after donepezil modestly improved cognitive scores in advanced Alzheimer’s patients in 2012. Because it was a secondary analysis, other experts said the results should be viewed as exploratory.

Drug companies including Eli Lilly, Biogen and Roche are working to develop true disease-modifying drugs for the memory-robbing disease, although progress is proving slow.