Comparison of the Efficacy of Tolterodine and Oxybutynin in Different Urodynamic Severity Grades of Idiopathic Detrusor Overactivity K. Giannitsas * , P. Perimenis, A. Athanasopoulos, K. Gyftopoulos, G. Nikiforidis, G. Barbalias Departments of Urology and Medical Physics, Patras University, Patras,Greece Accepted 29 July 2004 Available online 17 August 2004 Abstract Objective: To compare the efficacy of tolterodine and oxybutynin in the treatment of specific, accor urodynamic grade of severity, populations with overactive detrusor. Methods: In this open,randomized, two-way crossover study 128 women with urodynamically confirmed, idiopathic detrusor overactivity were recruited. Patients were categorized in 4 grades of severity gr to the characteristics of the first overactive detrusor contraction during filling cystometrogram: high pressure (grade-group I), high volume–high pressure (grade-group II), low volume–low pressure (gra and low volume–high pressure (grade-group IV). The primary outcome measure was average volume of void urine per micturition. Results: 107 patients successfully completed the study protocol and were included in the analyses: 36 in III, 25 in II and 6 in group I. In groups IV and III both oxybutynin and tolterodine significantly in average volume of voided urine per micturition but the differences between the drugs were not sign In group II neither of the drugs achieved significant changes in the outcome measure (p > 0.05). Conclusions: Tolterodine and oxybutynin are clinically equipotent in treating detrusor overactivity in specific severity groups of patients, although urodynamic effects are somewhat different. # 2004 Elsevier B.V. All rights reserved. Keywords:Overactive bladder; Severity; Treatment; Tolterodine; Oxybutynin 1. Introduction The overactive detrusor is a common urodynamic finding. Frequency, urgency and/or urge incontinence are the characteristic symptoms of this condition which seriously impair affected individuals’ quality oflife [1]. The grading of overactivity severity on the basis of urodynamic findings is more orless arbitrary and subjective and, although it seems to correlate to clinical severity [2], it has failed to meaningfully predict therapeutic outcome [3]. A number of medications, with common mechani of action the blockade of the cholinergically mediat detrusor contraction [4] have been tried for the trea ment of this disorder with varying degrees of succe The more frequently prescribed drugs are oxybutyn and tolterodine and their efficacy and safety have b assessed in detail [5,6].Although tolterodine has a superior side effect profile and tolerability, the effic cies of the two drugs seem to be equal in unselecte populations with overactive detrusor [7]. Neverthele patients who fail to improve on one drug, can do ve well on the other and vise versa. So far,there are neither clinical nor urodynamic criteria to predict th likelihood of a patient responding better to one or t other of these medications. The objective of this stu European Urology European Urology 46 (2004) 776–783 * Corresponding author. Present address: 90 Bizaniou Street, Athens 12136, Greece. Tel.+30 6947613550; Fax: +30 2610994668. E-mail address: giannitsascon@yahoo.gr (K. Giannitsas). 0302-2838/$ – see front matter # 2004 Elsevier B.V. All rights reserved. doi:10.1016/j.eururo.2004.07.021