J Clin Oncol

Oxybutynin shows promise for hot flashes in men on hormone therapy for prostate cancer

February 13, 2026

In the phase 2 randomized, double‑blind, placebo‑controlled Alliance A222001 trial, oxybutynin significantly reduced the frequency and severity of hot flashes in men undergoing androgen‑deprivation therapy (ADT) for prostate cancer. The study enrolled 88 men (81 evaluable) with at least 28 weekly hot flashes and compared oxybutynin 2.5 mg twice daily, 5 mg twice daily, or placebo over six weeks. Both oxybutynin doses produced substantially greater improvements than placebo, with average daily hot flash reductions of 4.77 (2.5 mg) and 6.89 (5 mg) vs. 2.15 with placebo, and larger declines in severity scores. Benefits appeared within the first treatment week and were sustained throughout the study period.

Treatment was well tolerated, with dry mouth as the most common adverse event and no grade ≥3 treatment‑related toxicities reported. Meaningful improvements in quality‑of‑life interference scores were seen among oxybutynin recipients.

Clinical takeaway: Oxybutynin may offer a safe, effective, and rapidly acting option for managing ADT‑associated hot flashes and may help patients maintain adherence to hormone therapy by reducing symptom burden.

Source:

Stish BJ, et al. (2026, January 26). J Clin Oncol. Alliance A222001: Oxybutynin Versus Placebo for the Treatment of Hot Flashes in Patients Receiving Androgen-Deprivation Therapy for Prostate Cancer. https://pubmed.ncbi.nlm.nih.gov/41587370/