Poster 37: Individualized Dosing of Extended-release Oxybutynin is Associated With Improved Outcomes in the Treatment of Urge Incontinence

Abstract

OBJECTIVE: To determine whether flexible dosing with the option to use the full range of approved doses of extended-release (ER) oxybutynin (5–30 mg daily) was associated with improvements in frequency of urge urinary incontinence (UUI) episodes, while maintaining treatment tolerability. METHODS: Data were combined from 3 flexible-dosing studies in which ER oxybutynin dose adjustments were made to achieve a maximal reduction in UUI episodes with acceptable tolerability. Doses were adjusted in 5 mg increments every 4–7 days, until the patient 1) reached complete continence, 2) achieved the highest level of continence attainable while still maintaining tolerability, as judged by each participant, or 3) reached the maximal dose of 30 mg. If the dose was deemed intolerable by the patient, it was reduced by 5 mg. Efficacy outcomes included mean reduction in UUI episodes and responder rate according to 2 definitions: a reduction of 70% or more in UUI episodes, and the attainment of complete continence. RESULTS: Data from 368 patients with UUI or mixed incontinence with urge predominating were pooled. For 30% of patients, the preferred dose was 10 mg daily, whereas 47% of patients were maintained at a dose of ER oxybutynin that was greater than 10 mg. Treatment with individualized doses produced an 83% decrease from baseline in UUI episodes, and 82.6% of patients achieved a decrease in UUI episodes of at least 70%. Complete continence was achieved by nearly 43% of participants overall. The cumulative percentage of patients achieving these goals increased with each dose increment. Therapy was well tolerated, with 7.6% of patients discontinuing because of adverse events. Moderate or severe dry mouth was reported by 23% of patients and was cited as the cause for early withdrawal by 5 (1.4%) patients. Incidence of dry mouth increased with dose (except at 30 mg daily), but no systematic increase in discontinuation rate for adverse events was observed. CONCLUSIONS: Almost half of the patients in this study increased their dose of ER oxybutynin beyond 10 mg. Individualized adjustments in ER oxybutynin dose resulted in effective and well tolerated management of urge incontinence.