Researchers from University College London (UCL) have suggested that drugs used to treat erectile dysfunction could also be linked to a reduced risk of developing Alzheimer’s disease (AD).
Published in the medical journal Neurology, researchers are now calling for further investigations to determine whether erectile dysfunction drugs could be used to prevent the most common form of dementia.
Affecting 900,000 people in the UK, AD is a brain disorder that progressively destroys memory, thinking skills and eventually the ability to carry out simple day-to-day tasks.
Erectile dysfunction drugs were first developed to treat high blood pressure and work by dilating blood vessels to increase blood flow.
Researchers looked at the medical records of nearly 270,000 men over the age of 40 with erectile dysfunction and discovered that those who were prescribed drugs known as phosphodiesterase 5 inhibitors (PDE5Is) were 18% less likely to develop AD compared to those who were not – there were 8.1 cases of AD among those treated with PDE5Is and 9.7 cases in those who did not take them.
PDE5Is work to relax smooth muscle in vessels in the penis to increase blood flow by raising levels of cyclic guanosine monophosphate (cGMP), a nucleotide secondary messenger.
In the brains of people with AD, previous studies have shown that cGMP is present at lower-than-usual levels.
Researchers also found that individuals who were issued the most prescriptions over the five-year study period had a 44% reduction. However, the team warned that they do not have information on whether participants actually used the drugs.
The potential of repurposing drugs already licensed for erectile dysfunction could advance progress and offer potential avenues to prevent or treat dementia-causing diseases.
Further investigation is required to confirm the findings of the study. UCL’s Ruth Brauer, who led the study, suggested that “a randomised, controlled trial with both male and female participants is warranted to determine whether these findings would apply to women as well”.
Dr Leah Mursaleen, head of research, Alzheimer’s Research UK, added: “We also need to understand how this evidence might apply to more diverse populations. The only way to do this is to keep up momentum in dementia research through continued investment.”