Can Viagra Cut Risk of Alzheimer’s Disease? What We Know

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  • A new study has found that people who took Viagra may be less likely to develop Alzheimer’s disease.
  • Experts stress more study is needed to verify the results.
  • Currently, there’s no cure for Alzheimer’s disease.

An erectile dysfunction drug, also used to treat high blood pressure, has already shown promise to treat or prevent Alzheimer’s disease (AD).

Now, new research adds to evidence finding this well-known drug might help reduce the risk of developing the degenerative condition.

“After searching [the] literature, we found multiple animal studies showing potential treatment effects of sildenafil in various AD preclinical models,” lead researcher Feixiong Cheng, PhD, of Cleveland Clinic’s Genomic Medicine Institute, told Healthline.

Cheng and team analyzed data from more than 7 million people to find sildenafil (Viagra) significantly reduced the likelihood of Alzheimer’s disease.

According to researchers, their findings, recently published in the journal Nature Aging, suggest it might soon be prescribed to fight dementia.

Study looked at over 1,000 FDA approved drugs

The study used insurance data, a large gene-mapping network, and integrated genetic and other information to discover which of about 1,600 Food and Drug Administration (FDA) approved drugs showed effectiveness against Alzheimer’s disease.

Researchers focused on drugs that target two proteins considered markers of Alzheimer’s disease, amyloid and tau, compared with drugs that only target one of them.

According to Cheng, many drug discovery projects targeting either protein alone failed in the past 20 years.

But for this project, they tested a new theory that “dual targeting” both amyloid and tau at the same time may provide better clinical benefits for people with Alzheimer’s.

He explained that Alzheimer’s disease is a “complex disease caused by many factors,” and multi-target drugs or combination therapy to target more than one disease pathway might offer greater benefits in treating the disease.

“By testing this novel hypothesis, we identified sildenafil as potential treatment of AD,” said Cheng.

Participants were nearly 70% less likely to develop Alzheimer’s disease

After a 6-year follow-up, Cleveland Clinic researchers found that people who took sildenafil were 69 percent less likely to develop Alzheimer’s disease than those who didn’t take the medication.

To further examine the drug’s potential to treat Alzheimer’s disease, Cheng and team created a lab model that showed sildenafil targeted tau protein and increased brain cell growth, revealing how the drug might work against the degenerative condition.

It’s important to note the study did not find sildenafil actually reduced the risk of Alzheimer’s disease. It was only associated with it. Cheng admitted there were limiting factors that indicate a need for more research.

“Although we adjusted many confounding factors in our patient data analysis based on our sizeable efforts, possible confounding factors may exist by our limited clinical knowledge of this complex disease,” he said.

Cheng emphasized that the findings must be confirmed in clinical trials before sildenafil can be used as a treatment for Alzheimer’s disease.

“We are working hard to pursue a RCT (randomized control trial) in the next step,” said Cheng.

Study had significant limitations

“This study looks at data from a very large number of people, but there are several important limitations to consider,” Professor Tara Spires-Jones, DPhil, deputy director of the Centre for Discovery Brain Sciences at the University of Edinburgh, said in a statement.

According to Spires-Jones, study data came from insurance claims, aren’t very detailed, and did not include information on other important risk factors for Alzheimer’s, like sex, risk genes, and socioeconomic status.  

 Spires-Jones pointed out there are other possible explanations for these findings.

“For example, we know that brain changes start decades before dementia symptoms [show] and it is possible that these early Alzheimer’s changes reduce sex drive, thus people wouldn’t ask for a prescription for erectile dysfunction,” she explained.

Only one drug has been approved to treat Alzheimer’s

Aducanumab (Aduhelm) is a recently FDA approved drug to treat Alzheimer’s disease. So far, it’s the only drug approved for this purpose.

It was granted accelerated FDA approval. This program allows for earlier approval of drugs to treat serious conditions and fill an “unmet medical need” based on a marker, such as laboratory measurement, physical sign, or other measure that might predict clinical benefit.

“Aducanumab is not a cure for Alzheimer disease,” Dr. Winston Chiong, member of the American Academy of Neurology (AAN) Ethics, Law, and Humanities Committee, told the Psychiatric Times.

“This is a high-cost drug that was approved by the FDA without convincing evidence of benefits and with known harms,” he noted.

According to the Weill Institute for Neurosciences, about 40 percent of people receiving aducanumab experience brain inflammation called amyloid-related imaging abnormalities (ARIA).

The condition involves brain bleeding, brain swelling, or both.

“Nearly 10 percent of those using the drug will likely need to discontinue their treatment due to concerns related to ARIA,” according to the institute.

Lifestyle changes that might reduce Alzheimer’s risk

A study published in June 2020 found that following at least 4 out of 5 healthy lifestyle behaviors could reduce dementia risk by 60 percent.

The behaviors were:

  • being physically active
  • not smoking
  • consuming light to moderate amounts of alcohol
  • eating a high quality diet
  • being mentally active

The plant-based Mediterranean-DASH Intervention for Neurodegenerative Delay (MIND) diet is the high quality diet researchers recommend.

“This observational study provides more evidence on how a combination of modifiable behaviors may mitigate Alzheimer’s disease risk,” Dr. Richard J. Hodes, director of the National Institute on Aging, said in a statement.

The bottom line

A new study finds that sildenafil, a drug FDA approved to treat high blood pressure and erectile dysfunction, may reduce the likelihood of developing Alzheimer’s disease by 69 percent.

Experts say the study had serious limitations and only shows an association with reduced risk.

They also say that simple lifestyle changes, like not smoking and keeping physically active, could significantly reduce the risk of dementia.

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