Low-dose oxybutynin for the treatment of urge incontinence: good efficacy and few side effects

Oxybutynin is an efficacious pharmacotherapeutic agent for the treatment of urge incontinence. However, many patients discontinue therapy because of the considerable side effects. This study aims at assessing the efficacy of a low-dose oxybutynin (2.5 mg three times daily) in relation to the concomitant profile of side effects.

Unselected primary care practice patients with involuntary urine loss were eligible for this study. A specially designed questionnaire was used to establish the diagnosis of symptomatic urge incontinence. All patients started with an oral dose of oxybutynin of 2.5 mg three times daily, and the responses with regard to efficacy and side effects were assessed after 2 and 6 weeks. Efficacy was evaluated using subjective patients' impression as well as data extracted from their voiding diaries. Adverse events possibly related to the use of oxybutynin were specifically asked for. Patients who experienced little or no symptomatic relief and who experienced no side effects were given a higher dose (5 mg three times daily).

General practitioners recruited 416 patients with symptomatic urge incontinence. Increasing the dose to 5 mg three times was preferred by 115 patients (28%). After 6 weeks 393 patients reported a partial or complete symptomatic cure (positive responder rate 95%). The average number of micturitions per 24 h decreased from 9.9+/-(SD)3.7 to 6.0+/-2.5 (p<0.001), and the average number of episodes of urine loss per 24 h decreased from 6.0+/-3.6 to 1.7+/-1.8 (p<0.001). A total of 123 patients (30%) reported side effects attributable to the use of oxybutynin; 42 patients (10%) had to stop the medication because of the severity of these side effects.

Successful pharmacological treatment of symptomatic urge incontinence can be given in a primary care setting using oxybutynin. Starting with a low dose of 2.5 three times daily, a subjective and objective efficacy can be achieved with fewer side effects than reported in the literature.