Study Links Viagra Use to Lower Risk of Alzheimer’s Disease

In the 1980s, the pharmaceutical company Pfizer began research into using sildenafil, a drug it had just synthesized, to treat angina and other cardiovascular conditions such as hypertension. In 1991, they began testing it on people, but the results were not what they expected. Nor can we say that it was a failure on a commercial level. Although it did not become popular for its intended use, it entered the pharmaceutical market in 1998 under the trade name Viagra. The story doesn’t end there, as a study published this Wednesday found a possible link between using erectile dysfunction medications and a lower risk of developing Alzheimer’s disease.

Work published in the magazine Neurology, from the American Academy of Neurology, followed a total of 269,725 men over age 59 who were diagnosed with erectile dysfunction over a five-year period, and 55% of them received medications for the problem. Over the five years that the study lasted, 1,119 volunteers developed Alzheimer’s disease, and after adjusting for factors such as age, smoking and alcohol consumption, the authors determined that those who took medications for erection problems were more likely to develop the condition. 18% lower. .

Great study, but with limitations

“These results are encouraging and justify further research,” says study co-author Ruth Brower of University College London, who points to the importance of finding “treatments that can prevent or delay the progression of Alzheimer’s disease.” The work, however, has some limitations: it is purely observational, cannot establish a cause-and-effect relationship, and is based on drug prescriptions, so it is impossible to know whether patients actually took them.

However, “this is a large study that shows an association between prescription of phosphodiesterase type 5 inhibitors and a reduced risk of Alzheimer’s disease in men” and “the risk appears to be dose dependent,” says a senior fellow at the UK Dementia Platform. researcher Ivan Koichev, talking with Science Media Center of Spain. That is, the work not only shows a connection, but it is stronger the more often drugs such as Viagra are prescribed.

“While this is an encouraging discovery, it does not yet confirm whether these drugs are directly responsible for reducing the risk of Alzheimer’s disease, or whether they can slow or stop the disease,” says Alzheimer’s UK research director Leah. Mursaleen., which indicates the direction of clinical trials that can confirm this relationship as cause-and-effect. In any case, the expert notes that “the possibility of reusing drugs already approved for the treatment of other diseases could accelerate progress and open new opportunities for preventing or treating diseases that cause dementia.” Koichev agrees, noting that this is a “promising strategy” because of its “known safety profile.”

In particular, drugs against erectile dysfunction are inhibitors of phosphodiesterase type 5, an enzyme that modulates the intensity of erections. This study raises the possibility that this therapeutic effect “directly affects neurons if the drug is able to cross the blood-brain barrier and/or increase blood flow,” explains a neuroscientist from the university’s Faculty of Pharmacy. Reading, Francesco Tamagnini. This researcher had already described in 2013 how nitric oxide, a gas that regulates blood pressure, interferes both peripherally with erectile function and in the modulation of neuronal function.