Extended-release oxybutynin therapy for vasomotor symptoms in women: A randomized clinical trial

Objective: Assess effects of once-daily, extended-release oxybutynin chloride on frequency and severity of vasomotor symptoms in healthy, postmenopausal symptomatic women. Methods: A 12-week, multicenter, double-blind, placebo-controlled, phase 2 clinical trial randomized naturally postmenopausal women experiencing at least seven moderate-to-severe vasomotor symptoms daily to oxybutynin 15 mg once daily (n=73) or placebo (n=75). Co-primary outcomes were the change from baseline to week 12 in the frequency and severity of moderate-to-severe vasomotor symptoms. Results: Significant reductions in both frequency and severity of moderate-to-severe vasomotor symptoms in women who received oxybutynin compared with placebo were observed at all weeks of treatment (P≤0.007, all time points) through week 12. Mean changes in frequency in the oxybutynin and placebo groups were -9.48 and -4.69 episodes/d, respectively, at week 12. Mean changes in severity (scale 0-3) in the oxybutynin and placebo groups were -1.27 and -0.30, respectively, at week 12. At the end of treatment, 73% of women in the oxybutynin group and 26.1% in the placebo group rated symptom improvement "much better" (P≤0.001). Women treated with oxybutynin showed significant improvement in sleep quality, sleep disturbance, and the global sleep index on the Pittsburgh Sleep Quality Index (P≤0.023). Dry mouth was reported by 52.1% of participants given oxybutynin and 5.3% of participants given placebo, leading to discontinuation of oxybutynin in 6.8% of participants. Conclusions: Oxybutynin is an effective, nonhormonal therapy for moderate-to-severe vasomotor symptoms in postmenopausal women.