Research Finds That Viagra Could Help Treat Alzheimer’s Disease

Sildenafil may be best known to people through its use for erectile disfunction as Viagra. However, it’s also used as a therapy for pulmonary hypertension as Revatio. Now, there’s hope that it could be helpful against Alzheimer’s disease, as well.

Using data from more than 7 million patients, a Cleveland Clinic research team recently screened more than 1,500 FDA-approved drugs to determine which could be repurposed as possible therapies for Alzheimer’s. In findings published in the journal Nature Aging, they say sildenafil is associated with a 69% lower incidence of Alzheimer’s. The next step would be clinical trials to test its effectiveness with Alzheimer’s patients.

Dr. Jean Yuan, program director of Translational Bioinformatics and Drug Development at the National Institute on Aging, says, “This paper is an example of a growing area of research in precision medicine where big data is key to connecting the dots between existing drugs and a complex disease like Alzheimer’s. This is one of many efforts we are supporting to find existing drugs or available safe compounds for other conditions that would be good candidates for Alzheimer’s disease clinical trials.”

To search for possible therapies among more than 1,600 FDA-approved drugs, the team used a large gene-mapping network to integrate genetic and other biologic data. Sildenafil was ultimately chosen as the best option, with researchers explaining that it has been shown to improve cognition and memory in preclinical trials.

To investigate sildenafil’s benefits, the team looked at data from more than 7 million Americans who either were or weren’t taking the drug. The data included patients who were using drugs currently in active Alzheimer’s clinical trials, including losartan and metformin, or have not yet been linked with treatment of the disease, including diltiazem and glimepiride.

After six years, those using sildenafil were 69% less likely to develop Alzheimer’s than those who were not using it. Compared with patients taking the other drugs, the risk was also substantially lower: 55% lower compared with losartan, 63% compared to metformin, 65% compared to diltiazem, and 64% compared with glimepiride.

Dr. Feixiong Cheng, who led the research, says, “Notably, we found that sildenafil use reduced the likelihood of Alzheimer’s in individuals with coronary artery disease, hypertension and type 2 diabetes, all of which are comorbidities significantly associated with risk of the disease, as well as in those without.”

The team then developed an Alzheimer’s patient-derived brain cell model using stem cells to test sildenafil further. Through this, they found that the drug increased brain cell growth and decreased the hyperphosphorylation of tau proteins, a hallmark of the disease. They say this shows how the therapy could impact the changes Alzheimer’s inflicts on the brain. However, there’s more work to do to determine how helpful sildenafil may be.

Dr. Cheng says, “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.”

The team hopes their method of screening drugs will also help find treatments for other neurodegenerative diseases.