Comparison of a 10-mg controlled release oxybutynin tablet with a 5-mg oxybutynin tablet in urge incontinent patients

Oxybutynin has long been used for the treatment of patients with detrusor overactivity and urinary urge incontinence. The short half‐life of oxybutynin administered as a conventional tablet formulation or syrup requires 2–3 times daily dosage to be effective. A new controlled release (CR) tablet for once‐daily administration has been developed. The efficacy and tolerability of this new controlled release tablet was compared to that of a 5‐mg conventional oxybutynin tablet administered twice daily. Seventeen female incontinent patients were studied in a double‐dummy crossover trial. Efficacy and tolerability were assessed by using a voiding diary, pad‐weighing test, visual‐analogue scale (VAS), and questionnaire. Adverse events were recorded spontaneously on a questionnaire by the patients themselves throughout the study. Serum concentrations of oxybutynin and its active metabolite N‐desethyloxybutynin were studied after both a single dose and multiple dosage. There was no difference in efficacy between the two formulations. Depending on the parameters tested, the change from baseline values in a positive direction ranged from 15 to 53%. The incidence of adverse events was similar with both formulations. Oxybutynin or its metabolite showed no cumulation during the multiple dosage with a 10‐mg CR tablet. The controlled release tablet formulation is as effective and as well‐tolerated as the conventional one, but has the advantage of only once‐a‐day dosage, enhancing treatment compliance. Neurourol. Urodynam. 16:533–542, 1997. © 1997 Wiley‐Liss, Inc.