A MEDICATION used to treat overactive bladder was able to reduce hot flashes in men receiving androgen deprivation therapy for prostate cancer, according to a study published Jan. 26, 2026, in the Journal of Clinical Oncology.

The study assessed the use of oxybutynin in 81 men who were on androgen deprivation therapy and reported at least 28 hot flashes a week, significantly impacting their quality of life. The men received either 2.5 milligrams of oxybutynin, 5 milligrams of oxybutynin or a placebo. Androgen deprivation therapy is a common type of hormone therapy used to treat prostate cancer that can lower testosterone levels and slow the growth of cancer cells. Not all patients receiving androgen deprivation therapy will experience side effects, but hot flashes do occur in 75% to 80% of patients, says Brad Stish, a radiation oncologist at Mayo Clinic Comprehensive Cancer Center in Rochester, Minnesota, who was the lead author on the study.

After six weeks, people who received the 2.5 milligram dose of oxybutynin reported about five fewer hot flashes per day and people who received 5 milligrams reported about seven fewer per day. People in the placebo group reported two fewer hot flashes per day. The researchers also measured hot flash scores, which assessed the reported frequency and intensity of hot flashes. At the end of six weeks, 79% of people receiving the 5-milligram treatment reported at least a 50% reduction in hot flash scores. There was a 57% reduction in the 2.5-milligram group and 32% reduction for those receiving a placebo.

“The real big takeaway was that there was a clear and broad effect from oxybutynin on reducing hot flashes, not only in number but also in severity,” Stish says.

Oxybutynin, a medication primarily used to treat overactive bladders since its introduction in 1975, has also been shown to reduce hot flashes for women experiencing menopause and is already used by some oncologists to treat hot flashes in prostate cancer patients. This study reinforces its efficacy to reduce hot flashes and potentially strengthens the case for using oxybutynin compared with similar drugs that have different side effect profiles, Stish says.

“We feel like this is something that should be part of conversations with prostate cancer patients who are experiencing hot flashes,” Stish says.

Options for Managing Hot Flashes

Paul Leger, an oncologist at Georgetown Lombardi Comprehensive Cancer Center in Washington, D.C., says he doesn’t think the recent study results will impact his decision making in caring for prostate cancer patients in his practice. “It’s adding information to what we already knew,” Leger says, adding that he believes the relatively small sample size of the study potentially calls for a larger follow-up.

Both Stish and Leger say hot flash treatments come with the risk of side effects. Oxybutynin can cause urinary retention, a condition where a person may not be able to completely empty their bladder of urine, which could be more uncomfortable depending on the size and location of a prostate tumor. Research has indicated that oxybutynin could impact cognition, including impairing memory and elevating the risk for dementia.

Leger has studied the efficacy of another approach to manage hot flashes among prostate cancer patients: waiting it out. Many men with early-stage cancer take a short course of hormone therapy and hot flashes abate within months of ending treatment, mirroring testosterone recovery. Leger points out that even patients who received a placebo in the oxybutynin study reported improvements, which suggests perception could be important and that offering reassurance that hot flashes will end could help some people. But he stresses that if a patient feels hot flashes are detrimental to daily life, they should speak with their oncologist about options.

“Some patients will find it very difficult to cope with hot flashes,” Leger says. Men who develop hot flashes while taking ADT for prostate cancer often report disrupted sleep, increased fatigue, and difficulties with concentration, work performance, and social interactions. “Particularly when we have an impression it causes a significant impact … I offer some kind of treatment.”

Kyle Bagenstose is a Philadelphia-based reporter specializing in health and environmental topics.