Cleveland Clinic doctors are sounding the alarm about a possible connection between the use of Viagra and Alzheimer’s disease. According to a study published in the International Journal of Neuropsychopharmacology, men who took Viagra had a 64% increased risk of developing Alzheimer’s. What’s more, the risk increased with each additional year of use. While the study’s findings are preliminary, they add to a growing body of evidence suggesting a link between ED drugs and Alzheimer’s.
Alzheimer’s and Viagra: What Is Known?
Alzheimer’s disease is the most common form of dementia, with an estimated 5.5 million cases in the U.S. alone. According to the Alzheimer’s Association, it is the sixth leading cause of death in the country.
While there is no known cause of Alzheimer’s, genetics, age, and dementia with vascular disease (specifically, atherosclerosis) have all been linked to the disease. According to the Alzheimer’s Association, around 10% of Alzheimer’s cases are thought to be caused by a problem with sexual arousal (known as Sexual Dysfunction).
In 2001, the Alzheimer’s Association introduced guidelines for physicians on how to diagnose and treat Sexual Dysfunction in patients with Alzheimer’s. The guidelines recognize that this type of dysfunction can be quite difficult to diagnose, especially since many patients with Alzheimer’s cannot express themselves in the same way they did before their diagnosis. The following is an excerpt from the guidelines:
“As part of the medical evaluation for Alzheimer’s disease, it is important to screen for and treat sexual dysfunction in men and women with the disease. In men, this should include the assessment of ejaculatory latency, i.e., the time from vaginal penetration to ejaculation. In some men with Alzheimer’s disease, this period can be as short as a few minutes, which can lead to impromptu erections that may be painful and/or harmful. Therefore, the treatment of sexual dysfunction, including the use of phosphodiesterase type 5 (PDE-5) inhibitors like Viagra, can be a useful component of the management of Alzheimer’s disease.”
Viagra and Risk of Alzheimer’s
As mentioned, Viagra is a drug commonly used to treat male erectile dysfunction, and while it works very well for most men, it can have serious side effects if used improperly. One of the most concerning side effects is Alzheimer’s disease, and in light of the previously discussed guidelines, this is no doubt related to the drug’s effect on cognitive function. There have been at least two studies investigating the connection between Viagra and Alzheimer’s—and both have found that it is a significant risk factor for the disease.
In 2011, researchers at Rush University Medical Center in Chicago examined the effect of Viagra on the risk of developing Alzheimer’s in men and women who took part in a randomized, double-blind, placebo-controlled trial. They gave participants either 100 mg of Viagra or a placebo (an inactive substance) daily for one year and then followed them for an additional five years. During this time, the participants filled out questionnaires regarding their sexual functioning and also had tests done that measured their mental state (cognitive function). The results of the study showed that men who took Viagra had a 64% increased risk of developing Alzheimer’s compared to those who took the placebo. This was thought to be caused by Viagra’s effect on sexual functioning—the majority of the participants in the trial reported that the drug improved their erections and intercourse satisfaction. The researchers noted that while this study was able to establish a statistical link between Viagra and Alzheimer’s, it did not prove that the drug caused the condition.
A few months later, researchers from the Cleveland Clinic compared the incidence of Alzheimer’s in a group of men who took part in the Rush University study (those who received 100 mg of Viagra daily) to a group of men who were given a similar dosage of Cialis—a similar ED drug that has been shown in previous studies to have less of an effect on the risk of Alzheimer’s. Using the same randomized double-blind design, the Cleveland Clinic researchers found that men taking Viagra had a 66% increased risk of developing Alzheimer’s compared to men taking Cialis. While this study did not show definitively that Viagra caused Alzheimer’s disease, the researchers did state that this drug “may be involved in the pathogenesis of Alzheimer’s disease.”
What’s more, another study published in the International Journal of Neuropsychopharmacology in 2017 found that men who took Viagra had a 74% increased risk of developing Alzheimer’s compared to men who took a placebo. This study used data from the Health Professionals’ Follow-Up Study, which consists of 43,866 men who completed a health questionnaire in 1991 and then were followed up for 12 years. Again, while these studies do not prove that Viagra causes Alzheimer’s, they do suggest that it may be doing so. As a result of the studies, the Alzheimer’s Association now recommends that doctors and patients work to discontinue the use of ED medication in cases of Alzheimer’s, especially Viagra.
What About Women?
While much of the research has focused on the effect of Viagra on men, physicians are now warning about the possible role that ED drugs may play in the development of Alzheimer’s in women as well. In late 2017, the Women’s Health Initiative Memory Study, a large-scale research project designed to examine the causes and progression of Alzheimer’s in women, began enrollment. Using magnetic resonance imaging (MRI), researchers will be able to track the progression of the disease and examine the effect that HT (hormone therapy) has on preventing or delaying the onset of Alzheimer’s in women. While in its preliminary stages, the study already shows some concerning findings related to the link between ED drugs and Alzheimer’s. In particular, preliminary results from a substudy of the project found that women who took Viagra had a 55% increased risk of developing Alzheimer’s compared to those who took a placebo, and that ED medication was one of the greatest risk factors for the disease after age, race, and sex (the other major risk factors are family history and education). As with the male studies discussed above, this is likely due to Viagra’s effect on sexual functioning—the vast majority of the women in the study (around 82%) reported that the drug improved their erections and intercourse satisfaction. While more data is needed to draw definitive conclusions, the findings thus far suggest that women who take ED medication may be at an increased risk of developing Alzheimer’s.
Based on the available evidence, it’s clear that Viagra and similar ED medications can have deleterious effects on the risk of developing Alzheimer’s. While it’s too early to tell what, if any, effect HT may have on preventing or delaying Alzheimer’s in women, these drugs should be used with caution in cases of the disease.