A new review led by researchers at the University of Exeter suggests that three already‑approved medicines might be repurposed to slow or even prevent Alzheimer’s disease. Rather than waiting for brand‑new compounds, the team examined drugs already in everyday use to see which ones could also protect the brain.
Why Repurposing Matters
Dementia remains the top cause of death in the United Kingdom, affecting roughly one million people, and about one in three newborns will develop some form of it during their lives. Building a novel drug from scratch typically demands 10–15 years of research and billions of pounds, with no guarantee of success. By redirecting medicines that have already passed safety checks, scientists hope to cut development time, lower costs, and bring effective treatments to patients faster.
How the Candidates Were Chosen
An international panel of 21 experts from universities, hospitals, the pharmaceutical sector, and patient groups evaluated 80 existing medications. After several rounds of scoring, three compounds emerged as the most compelling based on three criteria: relevance to Alzheimer’s‑related biology, positive signals in cell or animal experiments, and a well‑established safety profile for older adults.
Priority Drugs
- Shingles vaccine (Zostavax) – Emerging evidence links the varicella‑zoster virus to dementia. The vaccine’s ability to modulate the immune system may help offset the inflammatory changes that drive Alzheimer’s pathology.
- Viagra (sildenafil) – Pre‑clinical work shows the drug can shield neurons and curb the accumulation of tau protein. In mice, sildenafil also boosted memory performance, possibly by enhancing cerebral blood flow.
- Riluzole – Currently used for motor neuron disease, riluzole improved cognitive test scores and reduced tau levels in animal models, suggesting a neuroprotective effect.
Shingles Vaccine Leads the Pack
Among the three, the shingles vaccine stands out for its simplicity—just two doses are required—and its long safety record. Observational studies have hinted that vaccinated individuals are roughly 16 % less likely to develop dementia later in life. Researchers are now pushing for a large‑scale UK clinical trial that would enroll volunteers from the PROTECT online registry, a platform that tracks health and lifestyle data for brain‑health studies.
Other Compounds Reviewed
The panel also considered five additional drugs—fingolimod, vortioxetine, microlithium, dasatinib, and cytisine—but they did not meet the strict threshold to become “priority” candidates.
Expert Perspectives
Professor Anne Corbett, a dementia researcher at Exeter, emphasized that tackling Alzheimer’s will require every viable strategy, from novel drug discovery to clever repurposing of existing medicines. She warned that robust clinical trials are essential before any of these agents can be recommended for routine use.
Fiona Carragher, Chief Policy and Research Officer at Alzheimer’s Society, likened drug repurposing to the story of aspirin—originally a painkiller, now a staple for heart‑attack prevention. She called the approach one of the most exciting frontiers in dementia research today.