Erectile Dysfunction Drugs Linked to Lower Risk of Alzheimer’s Disease, Study Finds
In a surprising twist, a new study conducted by scientists in the UK has found that erectile dysfunction drugs, such as sildenafil (commonly known as Viagra), may be linked to a lowered risk of Alzheimer’s disease. While the findings do not establish a cause-and-effect relationship, they do suggest that further clinical trials should be conducted to confirm the potential benefits of these drugs.
Sildenafil and similar drugs fall under the category of phosphodiesterase type 5 inhibitors (PDE5Is). Originally developed to treat hypertension and chest pain, these drugs were later discovered to be highly effective in alleviating erectile dysfunction. This led to the creation of the iconic little blue pill, Viagra.
However, these drugs have uses beyond treating erectile dysfunction. Some have been approved for the treatment of pulmonary hypertension, or high blood pressure in the arteries of the lung. Scientists have also been exploring their potential for other medical conditions in both humans and animals.
One particularly intriguing possibility is their potential in combating Alzheimer’s disease. In 2021, a study funded by the National Institutes of Health (NIH) found evidence suggesting that sildenafil could prevent or delay the onset of Alzheimer’s in older individuals. The study indicated that taking the drug could reduce the relative risk of developing Alzheimer’s by up to 69% compared to not taking it, based on insurance claims data. However, a separate NIH-funded study conducted in October 2022 using Medicare data failed to find any link between reduced Alzheimer’s risk and sildenafil.
These conflicting findings caught the attention of Ruth Brauer, an epidemiologist at the University College London, and her team. They decided to conduct their own investigation using medical record data collected through the UK’s National Health Service. The advantage of this data was its long follow-up period and the inclusion of lifestyle variables that could affect Alzheimer’s risk.
Brauer’s team analyzed data from 269,725 older male residents who were newly diagnosed with erectile dysfunction and either given a prescription for a PDE5I or not. The outcomes of these two groups were tracked for an average of five years. By the end of the study period, 1,119 people had been diagnosed with Alzheimer’s disease. The results showed that those taking a PDE5I, specifically sildenafil, were significantly less likely to have Alzheimer’s compared to those who didn’t take the drug. After adjusting for other factors, the reduced risk was approximately 18%. It’s important to note that this reduced risk was only observed with sildenafil and not other PDE5Is, but this discrepancy may be due to the smaller number of users of these drugs rather than any biological difference.
The findings of Brauer’s study, published in the journal Neurology, suggest a more modest benefit from these drugs compared to the 2021 study. However, the fact that any protective effect was observed was surprising, considering the similar methodology used in the 2022 study. The longer follow-up data available to Brauer’s team may explain the different results. Brauer believes that this research could point to a real connection between PDE5Is and Alzheimer’s prevention.
While there are still many unanswered questions about this link, such as how these drugs work to prevent or delay Alzheimer’s, there are promising theories. Since PDE5Is are known to relax blood vessels, they may improve blood flow in the brain, which could have a neuroprotective effect. Animal data also suggests that these drugs may indirectly increase levels of acetylcholine, an important neurotransmitter for cognition that is depleted in individuals with Alzheimer’s.
It’s important to note that neither Brauer’s study nor any other study to date provides conclusive evidence that PDE5Is can stop Alzheimer’s. However, given the urgent need for treatments that can prevent or slow down this devastating condition, the authors argue that these drugs deserve further investigation from other researchers. Ideally, a randomized control trial should be conducted, involving both men and women diagnosed with mild cognitive impairment. Participants would be randomized to receive a PDE5I in conjunction with standard Alzheimer’s treatment or the standard treatment plus a placebo. Their cognitive outcomes would be tracked over time, providing a comprehensive understanding of the potential therapeutic benefits of these drugs.
In conclusion, while the link between erectile dysfunction drugs and a lower risk of Alzheimer’s disease is not yet fully understood, the findings of this study offer hope for potential new avenues of treatment. Further research is needed to confirm these findings and explore the mechanisms behind this connection. If proven effective, these drugs could provide much-needed relief for individuals at risk of developing Alzheimer’s and their families.
