Viagra and other anti-impotence drugs linked to lower risk of Alzheimer's in men

Drugs to treat erectile dysfunction, including Viagra, may be associated with a lower risk of Alzheimer's disease, a study of nearly 270,000 men with the disorder revealed.. The study, published by Neurology, does not prove that these drugs reduce the probability of Alzheimer's, it only indicates an observed association, as its authors make clear.

Although the association ends in nothing, the mere possibility that there are already drugs with potential benefit for Alzheimer's disease is an “encouraging result and justifies more research,” says the author of the work Ruth Brauer, from University College London, in the United Kingdom. , who highlights that “we desperately need treatments that can prevent or delay the development of Alzheimer's disease.”

If the suggested association is finally demonstrated, phosphodiesterase type 5 inhibitors, drugs that constitute a pillar in the treatment of erectile dysfunction, could also be used in the neurodegenerative disease. These medications work by dilating blood vessels to allow more blood to flow.

It would not be the first therapeutic repositioning of these drugs: sildenafil, the active ingredient in Viagra, was originally developed for pulmonary arterial hypertension and angina pectoris.. The notable side effect detected in the patients who received it marked the new direction of this pill, which we all already know.

However, before reaching that point, as Ruth Brauer points out, “more research is needed to confirm these findings, learn more about the possible benefits and mechanisms of these medications, and analyze the optimal dosage.”. Therefore, it justifies conducting “a randomized controlled trial with male and female participants to determine whether these findings would also apply to women.”

WHAT IS THE IMPACT OF THE USE OF DRUGS ON THE DEVELOPMENT OF ALZHEIMER'S?

The association between these drugs and a lower risk of Alzheimer's was seen by reviewing the medical records of 269,725 male participants with a mean age of 59 years who had recently been diagnosed with erectile dysfunction; The men did not have any memory or cognition problems at the beginning of the study. They were followed for an average of five years, in which 55% of participants who were prescribed ED medications were compared to 45% who had no prescriptions.. During the study, 1,119 people developed Alzheimer's disease.

Among participants who took the drugs, 749 developed the disease, corresponding to a rate of 8.1 cases per 10,000 person-years (person-years represent both the number of people in the study and the amount of time that each person is followed in the study). Among those who did not take the medications, 370 were diagnosed with Alzheimer's, corresponding to a rate of 9.7 cases per 10,000 person-years.

The research adjusted for other factors that could affect the rate of Alzheimer's disease, such as age, smoking and alcohol consumption.. They found that people who took erectile dysfunction medications were 18% less likely to develop Alzheimer's than people who did not.

The association was stronger in those who wrote more prescriptions during the study period. One of the limitations of the work is that it is based on prescription records, but the researchers are not certain about the participants' use of those prescriptions, a fact highlighted by Ivan Koychev, principal clinical investigator of the UK Dementia Platform, from the University of Oxford: “The study is limited by the challenge of establishing causal relationships in epidemiological studies. “In addition, these types of drugs are often taken as needed, so it is difficult to know how much was actually taken and how often.”

The researcher, however, points out to SMC of the United Kingdom that the reduction in the risk of Alzheimer's is greater as there are more prescriptions, and also “in people with risk factors for heart disease (high blood pressure, diabetes), which suggests “that the effect may be due to neuroprotection through vascular mechanisms.”

The evaluations of other experts collected by SMC of the United Kingdom also indicate that although there is no conclusive evidence that relates the drugs to a lower risk of Alzheimer's, the results do support more research.. “These types of drugs are worth continuing to study in the future,” says Tara Spiers-Jones, president of the British Neuroscience Association and professor at the UK Dementia Research Institute at the University of Edinburgh.

WHAT IS THE ROLE OF NITRIC OXIDE?

Another of these experts, Francesco Tamagnini, a neurophysiologist at the School of Pharmacy at the University of Reading, introduces nitric oxide into the hypothesis, whose role “in the consolidation, encoding and retrieval of memory has been known for some years.”

“Nitric oxide intervenes both peripherally in erectile function (by mediating vasodilation) and centrally in cognition, by modulating neuronal function. For example, it has been observed that nitric oxide-dependent transmission is necessary for perirhinal cortex-dependent visual recognition memory,” as shown in some of their published research.

“Theoretically, it is possible that promoting nitrergic transmission could improve memory function, but the question remains whether the observed association is describing a direct effect.”. This is a great study, but more strong evidence is needed to prove a mechanism of action. “It could be that it exerts a therapeutic effect by directly affecting neurons (if the drug is able to cross the blood-brain barrier) and/or by increasing blood flow, but both hypotheses must be tested.”