Repurposing Viagra shows promise as an affordable Alzheimer’s treatment

CLEVELAND, Ohio — It’s no secret what doctors prescribe sildenafil (Viagra) for — and why it’s so popular with men. However, the little blue pill may have an even more important benefit. Surprising new findings by researchers at the Cleveland Clinic suggest the erectile dysfunction drug holds promise as a potential means of treating the most common form of dementia, Alzheimer’s disease.

This latest report details evidence derived from various computational models, insurance claims, and observations of brain cells in Alzheimer’s patients. For reference, sildenafil is the main ingredient in drugs used to treat erectile dysfunction (Viagra), as well as pulmonary arterial hypertension (Revatio).

“Our findings provide further weight to re-purposing this existing FDA-approved drug as a novel treatment for Alzheimer’s, which is in great need of new therapies,” says Feixiong Cheng, Ph.D., who led the research, in a media release. “We used artificial intelligence to integrate data across multiple domains which all indicated sildenafil’s potential against this devastating neurological disease.”

Current estimates show that Alzheimer’s affects over six million Americans, and diagnoses will likely triple over the decades to come. Researchers stress the urgent need for rapid development of new prevention and treatment strategies. Drug repurposing, or the use of an existing drug for new therapeutic purposes, represents just one practical alternative to the costly and time-consuming traditional drug discovery process.

This new work builds on study authors’ earlier findings from 2021 that used computational models to initially identify sildenafil as a potential drug candidate for the prevention and treatment of Alzheimer’s disease.

This time around, Dr. Cheng, director of the Cleveland Clinic Genome Center, and his team performed an analysis on millions of anonymous insurance claims provided by two independent patient databases. This revealed a 30 to 54-percent reduction in the prevalence of Alzheimer’s disease diagnoses among patients who took sildenafil in comparison to others who did not take the drug — even after researchers adjusted for numerous confounding factors.

The study also shows that within the brain cells of Alzheimer’s patients, sildenafil appears to lower levels of neurotoxic tau proteins, considered a hallmark of Alzheimer’s disease. Study authors also note that neurons treated with sildenafil expressed genes related to cell growth, improved brain function, reduced inflammation, and additional processes promoting greater protection against the neural degeneration associated with Alzheimer’s disease.

All in all, this work demonstrates the feasibility of using computer models to identify potential new drug candidates in a fast, reliable manner. More specifically, the study represents a significant step forward in Alzheimer’s drug discovery efforts.

“After integrating this large amount of data computationally, it is rewarding to see sildenafil’s effects in human neurons and real-world patient outcomes,” Dr. Cheng concludes. “We believe our findings provide the evidence needed for clinical trials to further examine the potential effectiveness of sildenafil in patients with Alzheimer’s disease.”

The study is published in the Journal of Alzheimer’s Disease.