oxybutynin to reduce hot flashes in men receiving androgen-deprivation therapy (ADT) for prostate cancer

Oxybutynin is an anticholinergic agent available in oral and transdermal formulations that is commonly used for treating overactive bladder symptoms and has also shown activity for managing hot flashes (1).

Oxybutynin in in men receiving androgen-deprivation therapy (ADT) for prostate cancer (2):

• 6 week, double-blind, placebo-controlled trial (Alliance A222001) found that 79% of patients taking 5 mg of oxybutynin twice daily experienced at least a 50% reduction in hot flash scores
• found that 2.5 mg and 5 mg doses of oxybutynin produced significant, rapid (within one week), and durable improvements in hot flash frequency, severity, and quality of life compared to a placebo
  • on average, patients on the placebo arm, 2.5 mg oxybutynin arm, and 5 mg oxybutynin arm had reductions in hot flashes/day of 2.15, 4.77 (P = .02), and 6.89 (P < .001), respectively
• treatment was well-tolerated, with dry mouth being the most common side effect
  • dry mouth symptoms were more common among patients receiving oxybutynin, an effect that appeared be dose dependent, which has been previously demonstrated in studies of patients being treated for bladder symptoms
  • patients receiving oxybutynin on this study showed no significant change in IPSS scores related to incomplete emptying or straining
• study authors concluded:
  • “..data demonstrate a consistent, clinically and statistically significant benefit from oxybutynin and provides strong support for its use to manage hot flash symptoms in men receiving ADT..”

Reference:

1. Sexton T, Younus J, Perera F, Kligman L, Lock M. Oxybutynin for refractory hot flashes in cancer patients. Menopause. 2007 May-Jun;14(3 Pt 1):505-9.
2. Stish BJ et al. Alliance A222001: Oxybutynin Versus Placebo for the Treatment of Hot Flashes in Patients Receiving Androgen-Deprivation Therapy for Prostate Cancer. J Clin Oncol. 2026 Jan 26:JCO2501486.