OBJECTIVES: The aims of this study were to compare 12-week outcomes of single-therapy tolterodine (Detrol LA) extended release to intravaginal estrogen (Estrace) for overactive bladder (OAB) symptoms and characterize 24- and 52-week outcomes in women undergoing combined therapy. METHODS: A single-site randomized, open-label trial in women with urinary frequency, urgency, nocturia, and/or urgency urinary incontinence symptoms was performed. Fifty-eight participants were randomized to oral tolterodine extended release daily or intravaginal estradiol cream nightly for 6 weeks then twice per week. The primary outcome was change in Overactive Bladder Questionnaire (OAB-q) symptom bother score at 12 weeks. Secondary outcomes included the Health-Related Quality of Life Questionnaire (HRQL) of the OAB-q and a 3-day bladder diary. At 12 weeks, subjects were offered addition of the alternative therapy with follow-up at 24 and 52 weeks. RESULTS: There was no difference in symptom bother score improvement between the tolterodine and intravaginal estradiol groups baseline to 12 weeks (20.6 +/- 21.7, -15.8 +/- 23.3, respectively, P = 0.45). There was a significant within-group decrease in symptom bother score from baseline to 12 weeks (tolterodine, P < 0.0001, and intravaginal estradiol, P = 0.002). Secondary outcome improvement within groups was noted in the HRQL total, urinary incontinence episodes, and median voiding frequency (all P