Researchers at the Cleveland Clinic have determined that there is a drug that is already licensed and on the market that could be used to treat Alzheimer’s disease: Viagra.

Yes, that’s right, sildenafil (branded Viagra on the market) was identified out of more than 1,600 Food and Drug Administration-approved drugs as the most likely to present effective treatment for the degenerative disease using a large gene-mapping network, as it targets both amyloid and tau, two stamps of Alzheimer’s, rather than just one or the other.

“Sildenafil, which has been shown to significantly improve cognition and memory in preclinical models, presented as the best drug candidate,” reports study lead Dr. Feixiong Cheng.

Following the results of the gene-mapping network, the researchers then used a database of more than seven million people’s claims in the US to explore the relationship between sildenafil and Alzheimer’s disease. They discovered that sildenafil users were 69 percent less likely to develop Alzheimer’s than non-sildenafil users after six years of follow-up. The researchers also published further findings on a lab model they developed that showed how sildenafil increased brain cell growth and targeted tau proteins in Nature Aging.

According to Cheng, there is not enough evidence to demonstrate a causal relationship between sildenafil and Alzheimer’s disease, but they will need to conduct randomized clinical trials with both sexes and a placebo control to determine sildenafil’s efficacy.

However, as Dr. Susan Kohlhaas, the director of research at Alzheimer’s Research UK says, “being able to repurpose a drug already licensed for other health conditions could help speed up the drug discovery process and bring about life-changing dementia treatments sooner.”

Source study: Nature Aging—Endophenotype-based in silico network medicine discovery combined with insurance record data mining identifies sildenafil as a candidate drug for Alzheimer’s disease