Research highlighted the little blue pill as one potential drug to treat dementia
A study found that three existing drugs showed promise for preventing Alzheimer’s disease(Image: Getty)
A widely-prescribed medication could help ward off dementia, new research suggests. The study indicates that Viagra may reduce the risk of Alzheimer’s disease.
It was among three existing medicines identified as having this potential, alongside the shingles vaccine (Zostavax) and a motor neurone disease treatment (riluzole). Researchers hope these drugs could be repurposed to treat or prevent Alzheimer’s disease.
Developing completely new medications can take 10 to 15 years and cost billions of pounds – with no guarantee of success. As reported by Science Daily, repurposing drugs that are already licensed and widely used could provide a faster, safer, and more economical pathway to innovative Alzheimer’s therapies.
As part of the research, published in Alzheimer’s Research and Therapy, an international team of 21 dementia experts from universities, hospitals, and the pharmaceutical industry, together with people living with dementia, assessed 80 existing medications. Their objective was to determine which showed the most promise for treating or preventing Alzheimer’s disease, which represents more than half of all dementia cases.
After several rounds of evaluation, the panel identified three “priority candidates” for additional research. Each medication was chosen because it targets biological mechanisms associated with Alzheimer’s, has demonstrated promising outcomes in cell and animal studies, and is deemed safe for older adults.
Shingles vaccine (Zostava)
This showed the greatest promise for Alzheimer’s prevention. Given that immune system alterations are understood to contribute to Alzheimer’s disease, this vaccine engages with the immune system in a manner that could potentially counteract some of these detrimental changes.
Sildenafil (Viagra)
Studies indicate it might safeguard nerve cells and diminish the accumulation of tau, a protein that builds up abnormally in Alzheimer’s patients. Research conducted on mice revealed that sildenafil enhanced cognitive function and memory, potentially through improved cerebral blood flow.
Globally, around 16 million people are thought to use Viagra. In England, nearly 3.5 million prescriptions for Viagra were dispensed between September 2023 and August 2024.
Riluzole
Riluzole is currently prescribed for motor neurone disease. In animal studies, it has demonstrated improved cognitive performance and reduced levels of tau, a protein associated with Alzheimer’s disease.
What happens next?
Specialists are now calling for clinical trials to determine whether these drugs genuinely offer benefits to those living with Alzheimer’s or those at risk of developing it. Of the three treatments, the shingles vaccine stood out as particularly significant.
It requires just two doses and has a well-established safety record. Previous research suggests that those who received the vaccine were around 16 per cent less likely to develop dementia.
Researchers are looking to launch a large-scale UK clinical trial of the shingles vaccine, using the PROTECT online registry to track participants. PROTECT is a digital platform where volunteers complete annual health and lifestyle questionnaires and take part in brain health research.
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Dr Anne Corbett, professor of Dementia Research at the University of Exeter, said: “Beating dementia will take every avenue of research — from using what we already know, to discovering new drugs to treat and prevent the condition.
“Drug repurposing is a vital part of that mix, helping us turn today’s medicine for one condition, into tomorrow’s treatment for another.
“It’s important to stress that these drugs need further investigation before we will know whether they can be used to treat or prevent Alzheimer’s. We now need to see robust clinical trials to understand their true value and know for certain if they are effective to treat or prevent Alzheimer’s.”
Prof Fiona Carragher, chief policy and research Officer at Alzheimer’s Society, commented: “Dementia devastates lives, but we believe research will beat it. Years ago, we saw aspirin being repurposed from being a painkiller to helping people reduce their risk of heart attack or stroke.
“This is what we want to see in the field of dementia, and why we believe drug repurposing is one of the most exciting frontiers in dementia research.”
The research was financed by Alzheimer’s Society and spearheaded by the University of Exeter, with backing from the National Institute for Health and Care Research (NIHR), the Exeter Biomedical Research Centre, and the NIHR HealthTech Research Centre in Brain Health.
