Researchers have uncovered a drug repurposing potential for sildenafil, a common prescription medication known by the name Viagra, which is used in the treatment of erectile dysfunction. A study suggests Viagra could revolutionize the treatment and help in the prevention of vascular dementia, a condition for which specific therapies are currently unavailable.
Vascular dementia occurs when there is impaired blood flow to the brain, leading to symptoms such as difficulties with reasoning, planning, judgment, memory, and thought processes. Factors such as heart disease, stroke diabetes, high blood pressure, high cholesterol, and smoking raise the risk of developing vascular dementia.
According to the results of the latest study published in the American Heart Association's journal Circulation Research, the use of Viagra could improve blood circulation in the brain and responsiveness in the brain's blood vessels.
"This is the first trial to show that sildenafil gets into the blood vessels in the brain in people with this condition, improving blood flow and how responsive these blood vessels are. These two key factors are associated with chronic damage to the small blood vessels in the brain, which is the commonest cause of vascular dementia. This demonstrates the potential of this well-tolerated, widely-available drug to prevent dementia, which needs testing in larger trials," Dr. Alastair Webb from Oxford University, who led the study, said in a news release.
The study included a clinical trial with 75 participants who had experienced minor strokes and showed signs of small vessel disease. Participants were randomly assigned to receive either sildenafil, a placebo, or cilostazol (a similar drug) for three weeks. To assess the impact of each drug, the researchers conducted cardiovascular physiology tests, ultrasound examinations, and functional MRI scans on all participants.
As per the results of MRI scans and ultrasounds, the use of sildenafil improved blood flow in both large and small brain vessels of the brain. The participants on the drug also had improved blood flow response to carbon dioxide, suggesting better cerebrovascular function.
Although there was reduced blood vessel resistance in the brain with both sildenafil and cilostazol, sildenafil caused fewer side effects compared to cilostazol, particularly reduced risk of diarrhea.
"Professor Webb's findings are very encouraging and highlight the potential for preventing vascular dementia using existing drugs that target the underlying reduction in flow in the small blood vessels in the brain," said Professor Peter Rothwell, Founding Director of the Wolfson Centre for Prevention of Stroke and Dementia.
To further confirm the findings and to explore the impact of sildenafil on a broader scale, researchers recommend conducting larger-scale trials.
