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Researchers say erectile dysfunction drugs such as Viagra may help lower the risk of Alzheimer’s disease. Suzanne Opton/Getty Images
  • Researchers are reporting that erectile dysfunction drugs are associated with a lower percentage of Alzheimer’s cases in men.
  • They say erectile dysfunction drugs increase blood flow, which could help lower the risk of Alzheimer’s disease.
  • Experts say these drugs also need to be tested in women.

Erectile dysfunction drugs may lower the risk of Alzheimer’s disease in men by increasing a person’s blood flow, according to a study published today in the journal Neurology.

Researchers, however, note that study doesn’t necessarily directly prove that erectile dysfunction drugs reduce the risk of Alzheimer’s. It only says there’s an association.

The researchers point out that erectile dysfunction drugs, which dilate blood vessels to allow for more blood flow, were initially developed to treat high blood pressure. But now researchers say there could be yet another benefit.

“Although we’re making progress with the new treatments for Alzheimer’s disease that work to clear amyloid plaques in the brain for people with early stages of the disease, we desperately need treatments that can prevent or delay the development of Alzheimer’s disease,” said Ruth Brauer, a study author and lecturer at the University College London in the United Kingdom, in a press statement. “These results are encouraging and warrant further research.”

The research involved 269,725 male subjects with an average age of 59 who were also recently diagnosed with erectile dysfunction. None had any memory problems or other signs of Alzheimer’s at the beginning of the study.

Researchers followed participants for an average of five years. The study looked at the 55% of subjects with prescriptions for erectile dysfunction drugs and compared them to the 45% of participants who didn’t.

During the follow-up period, 1,119 men developed Alzheimer’s. Among those taking erectile dysfunction drugs, 749 developed Alzheimer’s – a rate of about 8 cases per 10,000 person-years (person-years represent the number of people in the study and the amount of time each one spends participating in the research).

Among those who didn’t take the drugs, 370 developed Alzheimer’s – a rate of more than 9 cases per 10,000 person-years.

Once the research team adjusted for other factors affecting the rate of Alzheimer’s, such as age, alcohol consumption, and whether someone smokes or not, they concluded that men taking erectile dysfunction drugs were 18% less likely to develop Alzheimer’s.

Researchers said the association between erectile dysfunction medications and Alzheimer’s was strongest in men who were prescribed the most medications during the study.

One of the study’s limitations was that the findings were based on prescription records. Researchers couldn’t verify whether subjects actually filled the prescriptions and used the drugs.

“More research is needed to confirm these findings, learn more about the potential benefits and mechanisms of these drugs, and look into the optimal dosage,” Brauer said. “A randomized, controlled trial with both male and female participants is warranted to determine whether these findings would apply to women as well.”

Dr. Clifford Segil, a neurologist at Providence Saint John’s Health Center in California who was not involved in the research, told Medical News Today that potential treatments for Alzheimer’s are not as simple as simply sending more blood through the body.

“When I examine patients with memory loss, the differential includes a condition called vascular dementia or multi-infarct dementia,” Segil said. “Vascular dementia is caused by multiple silent strokes in the brain and poor brain blood flow can cause these strokes. When talking about disrupted flow to the brain, neurologists concentrate on stroke or cerebrovascular accidents.”

Segil said erectile dysfunction drugs work by venous dilation and opening veins increases blood flow.

He noted the drugs are already used for other serious conditions.

“Erectile dysfunction medications are sometimes used by cardiologists to increase blood flow to the heart,” Segil said. “The researchers of this study should do an additional study to determine if vasodilating medications like erectile function have a direct effect on vascular dementia rather than Alzheimer’s dementia.”

Segil added he’s interested to see how the medication would affect females with Alzheimer’s.

“Memory loss remains a multifactorial condition caused by more than one thing,” Segil said.

Dr. J. Wes Ulm, a medical researcher and bioinformatics expert affiliated with the U.S. Department of Health and Human Services, told Medical News Today the study raises intriguing questions.

However, he said the onset of Alzheimer’s may differ from one person to another, which may be why drugs that simply increase blood flow haven’t been pursued more aggressively.

“Other findings have also pointed in a similar direction, (such as) the demonstrated value of smoking cessation and regular exercise in helping to ward off dementia, as well as of certain cognitive activities and forms of engagement — particularly foreign language learning, and possibly also undertakings like crossword puzzles or sudoku — that are likewise associated with improvements in cerebral blood flow to important brain regions,” Ulm said.

“There are other major factors, and it’s still unclear precisely how the molecular findings like senile plaques and neurofibrillary tangles are associated with the onset of dementia — to what extent they’re a cause vs. a correlating effect of something else,” he added.

Dr. Tommy Wood, an assistant professor of pediatrics and neuroscience at the University of Washington who also wasn’t involved in the study, told Medical News Today that cardiovascular risk factors are strongly associated with Alzheimer’s and dementia risk.

“Because of that, therapies that improve blood flow to the brain – ensuring oxygen and nutrients are getting to the active parts of the brain when they’re needed – may well provide a basis for future therapies in the prevention or treatment of those with dementia,” Wood said.

Even without taking medication for erectile dysfunction, there are ways to improve one’s odds against Alzheimer’s by getting more blood to the brain.

“Similarly, we know that physical activity is strongly protective against dementia and one major reason for that is that it supports vascular health and blood flow to the brain,” Wood said. “So, the premise described is certainly plausible.”