A short-term multicenter, randomized double-blind dose titration study of the efficacy and anticholinergic side effects of transdermal compared to immediate release oral oxybutynin treatment of patients with urge urinary incontinence

Purpose: We compared the short-term efficacy, safety and tolerability of transdermal versus oral oxybutynin in adults with urge urinary incontinence. Materials and Methods: Volunteers with detrusor instability currently responding to oral immediate release oxybutynin were enrolled in our study. Those patients presenting with recurrence of incontinent symptoms after a 8-week washout underwent confirmatory cystometrogram with subsequent randomization to transdermal or oral treatment. Matching active and placebo medications included matrix patches applied twice weekly and capsules taken 2 or 3 times daily. Dose titration was based on anticholinergic symptoms. Outcome measures included comparison of baseline to 6 week changes in incontinence episodes on a 3 day urinary diary, a visual analog scale far efficacy and anticholinergic symptoms reported on a questionnaire. Safety monitoring included adverse events and skin tolerability of the transdermal system. Results: A total of 76 patients were enrolled and 74 completed at least 4 weeks of treatment. Mean age in the transdermal and oral groups was 64 and 63 years, and 87% and 97% were female, respectively, Daily incontinent episodes decreased in the transdermal and oral groups (7.3 to 2.4 [66%] and 7.4 to 2.6 [72%], respectively, p = 0.39). The visual analog scale reduction in urinary leakage improved from washout in both groups (p <0.0001) with no difference between them (p = 0.9). Dry mouth occurred in significantly fewer patients in the transdermal (38%) compared with those in the oral group (94%, p <0.001). Of the patients in the transdermal group 67% noticed a reduction in dry mouth severity compared with previous oral treatment, and 90% had none or mild skin erythema. Conclusions: Transdermal delivery of oxybutynin resulted in comparable efficacy and a significantly improved anticholinergic side effect profile compared with oral administration in adults with urge urinary incontinence.