Roughly 10 million individuals worldwide have Parkinson’s disease (PD), and unfortunately, that number continues to grow as the population ages. There is no cure for PD, but medications can help control symptoms, often dramatically. Now, according to a large observational study led by scientists at the University of Iowa (UI), with colleagues in Denmark and China, taking a particular type of medication to treat enlarged prostate is associated with a reduced risk of developing Parkinson’s disease.

Their findings are published in JAMA Neurology, in a paper titled, “Association of Glycolysis-Enhancing α-1 Blockers With Risk of Developing Parkinson Disease.”

“A treatment that prevents or delays development of PD is a critical unmet need. Terazosin and closely related drugs were recently discovered to enhance glycolysis and reduce PD progression in animal models and human clinical databases,” the researchers wrote.

The researchers analyzed 300,000 older men from two large, independent patient datasets—the Truven Health Analytics MarketScan database in the United States and national health registries in Denmark—to investigate whether taking terazosin is associated with the development of Parkinson’s disease.

The findings build on previous preclinical research by the team, which showed that terazosin enhances cellular energy levels and can prevent or slow the progression of Parkinson’s disease in animal models.

Using the United States and Danish databases, the team identified 150,000 men newly started on terazosin or similar medications and matched them, based on age and clinical history to 150,000 men newly started on tamsulosin, another drug commonly used to treat enlarged prostate, but has no effect on cellular energy production

“We then tracked the health data on these men to determine how many in each group developed Parkinson’s disease,” explained Jacob Simmering, PhD, UI assistant professor of internal medicine and corresponding author of the study. “Men taking terazosin were 12–37% less likely to develop Parkinson’s disease during follow-up than men taking tamsulosin.”

The researchers also observed that longer duration of use of the energy-enhancing prostate drugs was associated with increased protective effects.

“Despite the relative differences in population and health care system structure, we found a similar protective effect in both countries,” Simmering added. “The replication of the finding in an international cohort is powerful evidence suggesting a causal effect. If these results are confirmed through further investigation, especially a randomized clinical trial, terazosin may provide neuroprotection and potentially prevent—and not just manage—Parkinson’s disease.”

The researchers wrote that future investigations are needed to identify whether a specific subset of patients are more likely to benefit from treatment. These findings can help provide hope and may one day lead to better treatment for this devastating neurodegenerative disease.