The same medications that treat erectile dysfunction might also help combat what’s known as vascular dementia — a common kind of age-related cognitive decline that happens when damaged blood vessels in the brain deprive cells of oxygen and nutrients.
Erectile dysfunction drugs work by increasing blood flow to the penis. In a new clinical trial published February 8 in Alzheimer’s & Dementia, scientists tested whether these medications might also help improve blood flow to the brain in older adults with narrowing brain arteries and symptoms of vascular dementia.
“Narrowing of the brain arteries is a common contributor to cognitive decline in older people and currently has no treatment,” says Jeremy Isaacs, MBBS, a principal clinical investigator on the trial and a neurologist at St. George’s University Hospitals in London.
For the trial, participants had two magnetic resonance imaging scans (MRIs) at least one week apart. One brain scan was done after they took a 20-milligram dose of the erectile dysfunction pill tadalafil (Cialis) and the other was done after they took a placebo pill. The goal was to see if MRIs showed increased blood flow with tadalafil.
Overall, the MRIs didn’t show a significant increase in blood flow in the brain after participants took a single dose of tadalafil.
However, when researchers looked only at results for participants over 70 years old, they did observe increased blood flow in white matter, a part of the brain that’s involved in the development of vascular dementia.
“This was a landmark study in which we attempted to reverse the reduction in brain blood flow characteristic of this condition,” Dr. Isaacs says. “Although we did not find a significant effect following a single dose of tadalafil, we can’t rule out the possibility of benefits from longer term use, for which further research is needed.”
Beyond its small size, another limitation of the trial is that it included some participants who were under age 50 — too young to experience meaningful changes in blood flow in the brain from one dose of an erectile dysfunction drug. It’s possible that the results might be more apparent if the trial had included only elderly participants or administered more doses of tadalafil over a longer period of time.
There is some previous research to suggest that erectile dysfunction drugs might play a role in preventing dementia.
One study, published in December 2021 in Nature Aging, for example, examined insurance claims data for 7.23 million people and found that patients taking the erectile dysfunction drug sildenafil (Viagra) were 69 percent less likely to develop Alzheimer’s disease, the most common form of dementia.
And a research review published in April 2020 in the Journal of Alzheimer’s Disease Reports found sildenafil associated with increased nerve tissue growth in the brain and less inflammation, both of which have been tied to a lower risk of dementia.
It makes sense that sildenafil and other erectile dysfunction drugs might have brain health benefits because they increase blood flow, according to Len Horovitz, MD, an internist and pulmonary specialist with Lenox Hill Hospital in New York City, who was not involved in the current study.
“Anything that increases blood flow will have a beneficial effect on brain function,” Dr. Horovitz said. “It wouldn’t surprise me if this is going to be a promising treatment — although whether it offers prevention, it’s hard to say.”
