Men undergoing treatment for prostate cancer may soon have a recent option for managing a common and often debilitating side effect: hot flashes. A recently published study in the Journal of Clinical Oncology indicates that oxybutynin, a medication typically prescribed for overactive bladder, significantly reduces the frequency and intensity of these hot flashes compared to a placebo.
The findings offer a potential breakthrough for the estimated 60% to 80% of men experiencing hot flashes as a result of androgen-deprivation therapy (ADT), a standard treatment for prostate cancer. These vasomotor symptoms can severely disrupt sleep, mood, and overall quality of life, sometimes even leading patients to consider discontinuing vital treatment. Finding effective and well-tolerated management strategies for hot flashes is therefore a critical area of research.
The phase 2 clinical trial, conducted by researchers at the Alliance for Clinical Trials in Oncology (A222001), enrolled 88 men with prostate cancer who reported frequent hot flashes whereas receiving ADT. Participants were randomly assigned to receive either 2.5 mg or 5 mg of oxybutynin twice daily, or a placebo, for a period of six weeks. The primary endpoint of the study was the change in patient-reported hot flash scores from baseline at the end of the treatment period.
Results showed a clear benefit for those receiving oxybutynin. Men in the higher-dose group (5 mg twice daily) experienced an average reduction of nearly seven hot flashes per day, compared to just two fewer hot flashes per day in the placebo group, according to the study published January 26, 2026 via HealthDay. Notably, over 75% of men in the 5 mg oxybutynin group reported at least a 50% reduction in the severity of their hot flashes.
Oxybutynin’s Impact on Quality of Life
Beyond simply reducing the number of hot flashes, the study similarly demonstrated improvements in patients’ daily functioning and overall quality of life. Participants taking oxybutynin reported less disruption to sleep, work, social activities, and general well-being. Improvements were measured using the Hot Flash-Related Daily Interference Scale (HFRDIS), with the 5 mg oxybutynin arm showing a significant improvement of over 20 points compared to the placebo group, as detailed in the Journal of Clinical Oncology.
“Hot flashes are often underestimated in men, but they can have a real and lasting impact on quality of life during prostate cancer treatment,” explained Dr. Bradley J. Stish, the study’s first author and a radiation oncologist at Mayo Clinic. “This trial shows that oxybutynin can provide significant relief with a favourable safety profile.”
Safety and Tolerability
The study also highlighted the favorable safety profile of oxybutynin. No treatment-related serious adverse events were reported during the six-week trial. The most commonly reported side effect was dry mouth, which was more prevalent at the higher dose of 5 mg twice daily. This aligns with the known side effects of oxybutynin when used for its primary indication of overactive bladder.
Researchers noted that oxybutynin has previously shown effectiveness in reducing hot flashes in women, but evidence supporting its use in men was limited prior to this study. The findings, as reported by PubMed, expand the available treatment options for men experiencing this challenging side effect of prostate cancer treatment.
Future Research and Clinical Implications
While these results are promising, researchers emphasize the necessitate for larger, more comprehensive studies to confirm these findings and determine the optimal dosage of oxybutynin for managing ADT-associated hot flashes. Further investigation is also warranted to understand the underlying mechanisms by which oxybutynin alleviates these symptoms in men.
“These results expand the options available to clinicians and patients who are trying to manage a challenging side effect of prostate cancer treatment,” Dr. Stish added. “Having additional, well-tolerated choices matters.”
The availability of a relatively safe and effective treatment option like oxybutynin could significantly improve the quality of life for many men undergoing ADT for prostate cancer. As research continues, clinicians will be better equipped to personalize treatment plans and address this often-overlooked side effect.
Disclaimer: This article is for informational purposes only and should not be considered medical advice. Please consult with a qualified healthcare professional for any health concerns or before making any decisions related to your health or treatment.
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