A medication commonly used to treat overactive bladders significantly reduced hot flashes in men receiving hormone therapy for prostate cancer.
The phase 2 study, published in the Journal of Clinical Oncology, found that oxybutynin worked better than a placebo at reducing how often hot flashes occurred and how intense they were in such patients.
Men who took oxybutynin also reported improvements in their day-to-day functioning and overall quality of life.
Hot flashes affect an estimated 60% to 80% of men receiving androgen-deprivation therapy, and can interfere with sleep, mood and overall well-being.
For some patients, these symptoms are severe enough to make it difficult to continue treatment.
“Hot flashes are often underestimated in men, but they can have a real and lasting impact on quality of life during prostate cancer treatment,” says study first author and Mayo Clinic radiation oncologist Dr Bradley Stish.
“This trial shows that oxybutynin can provide significant relief with a favourable safety profile.”
The study enrolled 88 men with prostate cancer who were experiencing frequent hot flashes while receiving androgen-deprivation therapy.
Participants were randomly assigned to receive oxybutynin at one of two doses, or a placebo, for six weeks.
Men who received the higher dose of oxybutynin experienced the greatest benefit, with an average reduction of nearly seven hot flashes per day, compared with about two fewer hot flashes per day in the placebo group.
More than three-quarters of the men receiving the higher dose achieved at least a 50% reduction in hot flash severity.
Patients taking oxybutynin also reported less disruption to sleep, work, social activities and overall quality of life.
No treatment-related serious adverse events occurred during the study.
The most common side effect was dry mouth, which was more frequent at higher doses.
Oxybutynin has previously been shown to reduce hot flashes in women, but evidence in men had been limited.
“These results expand the options available to clinicians and patients who are trying to manage a challenging side effect of prostate cancer treatment,” says Dr Stish.
“Having additional, well-tolerated choices matters.”
Researchers note though that larger studies will be needed to confirm the findings and determine the optimal dose.
