Viagra linked to lower risk of Alzheimer's dementia by US researchers

Scientists in Cleveland have published their study into the effects of Viagra, also known as sildenafil, for people at risk of vascular dementia - the second most common form of dementia after Alzheimer's - which occurs when reduced blood flow damages the brain.

US researchers published their study in the journal Nature Aging, finding that men who were on the drug had a lower risk of Alzheimer's after analysing a database of personal medical data spanning six years and involving more than 7.23m individuals.

The study found that high doses of Viagra (larger than a person would normally take) had the ability to increase brain cell growth and reduce protein accumulation in lab studies of human tissue.

Experts say that this discovery could contribute to repurposing an existing drug which would a be quicker, simpler and cheaper option in treating dementia than developing a brand new treatment.

Lead investigator Dr Feixiong Cheng said: "Because our findings only establish an association between sildenafil use and reduced incidence of Alzheimer's disease, we are now planning a mechanistic trial and a phase II randomized clinical trial to test causality and confirm sildenafil's clinical benefits for Alzheimer's patients."

Other researchers however have questioned whether the drug itself was the main cause in keeping the men's brains healthy.

UK brain research expert Prof Tara Spires-Jones, from the University of Edinburgh, said: "More work will be needed to know whether this drug can indeed lower risk for Alzheimer's disease.

"While these data are interesting scientifically, based on this study, I would not rush out to start taking sildenafil as a prevention for Alzheimer's disease."