A new study describes in using Viagra: for treatment against Alzheimer's disease.
Researchers at the Cleveland Clinic used a massive gene-mapping network to combine genetic and other data to identify which of the more than 1,600 FDA-approved medications could be a viable treatment for Alzheimer's disease.
They assigned treatments that target both amyloid and tau - two hallmarks of Alzheimer's disease - better rankings than drugs that only target one of the two.
The best pharmacological candidate was sildenafil, which has been demonstrated to improve cognition and memory in preclinical animals, according to Feixiong Cheng, the study's lead researcher.
Sildenafil is sold under the brand name Viagra.
Researchers then compared sildenafil users to non-users in a database of claims from more than 7 million patients in the U.S. to look into the link between sildenafil and Alzheimer's disease outcomes.
After six years of follow-up, they discovered that sildenafil users were 69% likely than non-sildenafil users to develop Alzheimer's disease. To learn more about sildenafil's potential role in Alzheimer's disease, scientists created a lab model that showed the drug increased brain cell growth and targeted tau proteins, providing insight into how it might influence disease-related brain changes.
The study does not prove a causal link between sildenafil and Alzheimer's disease, according to Cheng. To determine sildenafil's efficacy, he noted, randomized clinical trials involving both sexes with a placebo control were required.
Because males are more commonly prescribed sildenafil, the study was unable to find any possible benefits in females in terms of Alzheimer's risk.
Because of its main function - increasing blood flow by relaxing or expanding blood vessels - sildenafil was originally developed as a cardiac medication. Doctors realized it had a similar impact elsewhere in the body, including the arteries of the penis, and it became a successful erectile dysfunction medication.
However, experts believe it may have more applications. Sildenafil is already prescribed for pulmonary hypertension in both men and women.
Hundreds of millions of individuals worldwide are affected by Alzheimer's disease, the most common form of age-related dementia. Despite the growing number of cases, there is presently no effective treatment available.
Although the specific cause of this type of dementia is unknown, doctors do know that abnormal protein deposits accumulate in the brains of those who suffer from it.
Experts say that work like this is interesting because repurposing an existing drug could be faster, easier, and less expensive than researching and developing a brand new treatment.
The findings were published in Nature Aging.
