Ditropan® is indicated for the treatment of urge urinary incontinence, however patients tend to discontinue the medication or decrease the dose due to anticholinergic side effects. OROS® oxybutynin, a continuous release formulation, is expected to have fewer anticholinergic side effects than Ditropan® and may provide equal or better efficacy compared to Ditropan®. This is a randomized, multi-center, double-blind, parallel group, dose-escalation study comparing the efficacy and safety of OROS® oxybutynin to Ditropan® for the treatment of urge or mixed urinary incontinence at the minimum effective dose (MED), the maximum tolerated dose (MTD), or the maximum allowable dose (MAD) permitted under this protocol. Patients in both treatment groups begin study drug treatment at an oxybutynin dose of 5 mg per day. The dose is changed in 5 mg increments at 4- to 7-day intervals, depending on the safety and efficacy of the current dose. The maximum allowable dose for Ditropan® is 20 mg per day, which is the maximum daily adult dose specified in its labeling. Because controlled delivery of oxybutynin by an OROS® dosage form could potentially reduce side effects, it is believed that the drug could possibly be tolerated at doses higher than 20 mg per day. Consequently, the maximum allowable dose for OROS® oxybutynin is 30 mg per day, administered as a single daily dose. The primary measures of effectiveness include the change from baseline in the following assessments: the number of urge urinary incontinence episodes per week, the total number of urinary incontinence episodes, and total void frequency (normal and incontinent). Safety evaluations include the incidence of adverse events, physical examination and medical history, clinical laboratory tests, urinalysis, electrocardiograms (ECGs), vital signs, and the Anticholinergic Effects Assessment (ACEA) questionnaire.~OROS® (oxybutynin chloride) 5 mg tablets, one to six tablets per day (5 mg/day to 30 mg/day) as a single morning oral dose for 11 days up to 70 days, and Ditropan (oxybutynin chloride) 5 mg tablets, one to four tablets per day orally (5 mg per day to 5 mg four times per day) for 10 daysup to 61 days.
The purpose of this study is to compare the efficacy and safety of OROS® oxybutynin to that of Ditropan® (immediate-release oxybutynin) for the treatment of patients with urge or mixed urinary incontinence. Oxybutynin is an antispasmodic, anticholinergic medication for the treatment of the symptoms of overactive bladder.