MINNEAPOLIS, MN – Certain drugs used to treat urinary symptoms due to an enlarged prostate may be associated with a reduced risk of dementia with Lewy bodies, according to a study published in the June 19, 2024, online issue of Neurology^®, the medical journal of the American Academy of Neurology. Dementia with Lewy bodies is a progressive neurodegenerative disorder that can cause memory and thinking issues, movement problems and issues such as hallucinations. 

The results do not prove that these drugs reduce the risk of dementia with Lewy bodies; they only show an association. 

“These results are exciting because right now there are no drugs to prevent or treat dementia with Lewy bodies, which is the second most common neurodegenerative type of dementia after Alzheimer’s disease,” said study author Jacob E. Simmering, PhD, of the University of Iowa in Iowa City. “If we can determine that an existing drug can offer protection against this debilitating disease, that has the potential to greatly reduce its effects.” 

The study looked at male participants taking different types of drugs to treat urinary problems caused by an enlarged prostate, a common problem for older men. The drugs terazosin, doxazosin and alfuzosin could block brain cell death by activating an enzyme important for energy production in brain cells. Previous studies have shown an association between these drugs and Parkinson’s disease, which is similar to dementia with Lewy bodies. 

For the study, researchers looked at a health information database for male participants who had started taking one of those three drugs. They were compared to people who took two other types of prostate drugs that do not activate the same enzyme—tamsulosin and the 5a-reductase inhibitors finasteride and dutasteride, called 5ARIs. 

Overall, there were 126,313 people taking terazosin, doxazosin or alfuzosin, 437,045 people taking tamsulosin and 80,158 people taking a 5ARI. Researchers followed the participants for an average of three years to see who developed dementia with Lewy bodies. 

There were 195 people who developed the disease among those taking terazosin, doxazosin or alfuzosin, for a rate of 5.21 cases per 10,000 people per year. Among those taking tamsulosin, there were 1,286 cases, for a rate of 10.76 per 10,000 people per year. Among those taking 5ARIs, there were 193 cases, for a rate of 7.78 per 10,000 people per year. 

Once researchers matched the groups by age, other health conditions and other factors that could explain the differences between groups, they found that people taking terazosin, doxazosin or alfuzosin were 40% less likely to develop dementia with Lewy bodies than people taking tamsulosin and 37% less likely than people taking the 5ARIs. The risk of developing the disease was similar among those taking tamsulosin and the 5ARIs. 

“More research is needed to follow people over time and determine whether there is a cause-and-effect relationship here, but it is promising to think that these drugs could have a protective effect on this disease that will likely affect a larger number of people as the population ages,” Simmering said. 

Since only male participants were included in the study, the results may not apply to female participants. Another limitation of the study is that dementia with Lewy bodies can be difficult to diagnose, so it’s possible that not all people with dementia with Lewy bodies were correctly diagnosed.