Researchers have identified three existing, approved drugs-a shingles vaccine, an erectile dysfunction medication, and a treatment for ALS-as potential candidates for treating or preventing alzheimer’s disease, offering a potentially faster and more affordable path to new therapies. The University of Exeter-led study, published in Alzheimer’s Research & Therapy, focused on “drug repurposing,” a strategy gaining traction as traditional drug progress for neurodegenerative diseases faces significant hurdles. With over 6 million Americans currently living with Alzheimer’s, according to the Alzheimer’s Association, this research offers a glimmer of hope for a condition with limited treatment options.
Published on February 7, 2026 – 11:15 PM GMT
A new study led by the University of Exeter and funded by Alzheimer’s Society has identified three already-approved drugs that may play a role in treating or preventing Alzheimer’s disease. The research offers a potentially faster and more cost-effective pathway to finding treatments for the devastating neurodegenerative condition, which currently affects millions worldwide.
The findings, recently published in the journal Alzheimer’s Research and Therapy, highlight the potential of repurposing existing medications. The study points to the shingles vaccine (Zostavax), the erectile dysfunction drug Viagra (sildenafil), and riluzole – currently used to treat amyotrophic lateral sclerosis (ALS) – as promising candidates.
Developing new drugs for dementia is a lengthy and expensive process, often taking 10 to 15 years and carrying no guarantee of success. Repurposing approved drugs offers a quicker, less expensive, and potentially safer alternative, researchers say.
The study, supported by the National Institute for Health and Care Research (NIHR) and the Exeter Biomedical Research Centre, involved a comprehensive review of 80 existing drugs. A panel of 21 international experts from academia, hospitals, the pharmaceutical industry, and individuals living with dementia participated in the effort to identify drugs with the greatest potential to treat or prevent Alzheimer’s, which accounts for over half of all dementia cases.
Three Candidates Targeting Different Pathways
The expert panel prioritized three drugs that each target different biological processes linked to Alzheimer’s disease. These medications have shown positive results in laboratory and animal studies and have established safety profiles for use in older adults.
The shingles vaccine (Zostavax) emerged as a leading candidate. Research suggests a link between shingles and an increased risk of dementia, and the vaccine is thought to potentially protect the brain from damaging changes by boosting the immune response.
Sildenafil (Viagra) is also showing promise, with the potential to protect nerve cells and reduce the buildup of tau protein in the brain. Studies on mice have demonstrated improved cognitive performance, potentially due to increased blood flow to the brain.
Riluzole, the third drug identified, has been shown to reduce levels of tau protein and enhance cognition in animal studies. It is currently used to treat motor neuron disease.
Shingles Vaccine Shows Early Promise
The shingles vaccine stands out as the most promising treatment option due to its simple two-dose regimen and strong safety record.
Previous studies have indicated that individuals who receive the vaccine may have up to a 16% lower risk of developing dementia. Researchers are now planning a large-scale clinical trial in the United Kingdom to further investigate its effectiveness.
“Drug repurposing is a key part of our strategy, helping us to turn today’s drugs into tomorrow’s treatments,” said Dr. Anne Corbett, Professor of Dementia Research at the University of Exeter. “However, robust clinical trials are needed to determine how effective these drugs are at preventing or treating the condition.”
