Objective: To compare the efficacy of tolterodine and oxybutynin in the treatment of specific, according to their 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 groups, according to the characteristics of the first overactive detrusor contraction during filling cystometrogram: high volume-low pressure (grade-group I), high volume-high pressure (grade-group II), low volume-low pressure (grade-group III) and low volume-high pressure (grade-group IV). The primary outcome measure was average volume of voided urine per micturition.
Results: 107 patients successfully completed the study protocol and were included in the analyses: 40 in group IV, 36 in III, 25 in II and 6 in group I. In groups IV and III both oxybutynin and tolterodine significantly increased the average volume of voided urine per micturition but the differences between the drugs were not significant (p > 0.05). 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.