Top Line: Does oxybutynin reduce hot flashes on ADT?
The Study: Hot flashes are a common problem for men receiving ADT for prostate cancer. In Alliance A222001, 88 patients who were on ADT and reported at least 28 hot flashes per week (average was 10.1 per day) were randomized to receive placebo, oxybutynin 2.5mg twice daily, or oxybutynin 5mg twice daily. Why oxybutynin? The mechanism isn’t completely clear, but its antimuscarinic properties may play a role in modulating central thermoregulatory pathways. The placebo effect was at play as all patients in all three arms saw a reduction hot flashes per day. However, those who took oxybutynin saw a significantly greater reduction. Daily hot flash scores were 4.85 for placebo compared with 9.94 for 2.5 mg BID and 13.95 for 5 mg BID. Furthermore, oxybutynin resulted in no grade 3+ adverse events.
TBL: Oxybutynin significantly reduces hot flash symptoms among men receiving ADT for prostate cancer. | Stish, J Clin Oncol 2026
The Study: Hot flashes are a common problem for men receiving ADT for prostate cancer. In Alliance A222001, 88 patients who were on ADT and reported at least 28 hot flashes per week (average was 10.1 per day) were randomized to receive placebo, oxybutynin 2.5mg twice daily, or oxybutynin 5mg twice daily. Why oxybutynin? The mechanism isn’t completely clear, but its antimuscarinic properties may play a role in modulating central thermoregulatory pathways. The placebo effect was at play as all patients in all three arms saw a reduction hot flashes per day. However, those who took oxybutynin saw a significantly greater reduction. Daily hot flash scores were 4.85 for placebo compared with 9.94 for 2.5 mg BID and 13.95 for 5 mg BID. Furthermore, oxybutynin resulted in no grade 3+ adverse events.
TBL: Oxybutynin significantly reduces hot flash symptoms among men receiving ADT for prostate cancer. | Stish, J Clin Oncol 2026