Sildenafil, better known by the trade name Viagra, is the most popular drug in the world for the treatment of erectile dysfunction. It has a powerful vasodilatory action that helps the flow of blood into the penis in the presence of sexual arousal, producing an erection even when age, diseases and medications may have made it difficult to obtain. However, the same mechanism of action also makes it useful for other vascular pathologies. And among these there could also be Alzheimer’s, as demonstrated by a new international study just published in the journal Neurology.
The need for drugs against this serious degenerative disease, moreover, is more current than ever, and for years has been leading researchers to explore every possible path to reach their goal. The incidence of Alzheimer’s disease is increasing, due to the aging of the population in developed countries, and in a country like the United States there are already 6.7 million people aged 65 and older living with Alzheimer’s , a number that could more than double by 2060 unless a way is found to reverse this trend.
“Viagra May Help Reduce the Risk of Alzheimer’s Disease”
Identifying a drug already approved for other pathologies that demonstrates a concrete protective effect against Alzheimer’s would be extremely interesting, because it would allow many regulatory steps to be skipped, and to quickly bring the therapy to millions of people who could benefit from it today. For this reason, for years we have been thinking about drugs for erectile dysfunction, known as phosphodiesterase type 5 or PDE5 inhibitors, such as Viagra, whose vasodilatory effect could prove useful against the vascular factors that contribute to the development of Alzheimer’s.
In fact, a 2021 study showed that taking sildenafil reduced the chances of being diagnosed with Alzheimer’s by almost 70%. But the results of another research, shorter and on a smaller number of patients, in 2022 had cast doubt on the protective effects of Viagra. For this reason, the new research published in recent days could be important in moving the needle again.
The study analyzed prescriptions issued to nearly 270,000 men aged 40 and over with a new diagnosis of erectile dysfunction, using electronic medical records from the United Kingdom. About half of the people were prescribed sildenafil or a similar erectile dysfunction drug, which belongs to the same class of drugs as PDE5 inhibitors. The researchers then compared the incidence of Alzheimer’s between patients who took Viagra or another similar drug, and those who did not.
In total, 1,119 men in the study population developed Alzheimer’s disease. And those who were prescribed sildenafil or another similar drug were 18 percent less likely to develop the disease. Furthermore, the risk was even lower for those who had received more than 20 prescriptions over a 5-year period, suggesting the possibility that high doses of the drug are more effective in prevention.
When patients were grouped by drug prescribed, only sildenafil, among all PDE5 inhibitors, was associated with a reduced risk of Alzheimer’s.
“Further research is needed to confirm these findings, delve deeper into the potential benefits and mechanisms of these drugs, and examine optimal dosing,” says Ruth Brauer, pharmacoepidemiologist at University College London and author of the study. “And a randomized, controlled trial with male and female participants will be needed to determine whether these findings are also applicable to women.”