A randomized double-blind crossover trial of intradetrusor injection of botulinum a toxin for severe and refractory idiopathic detrusor overactivity in women

Abstract

Intradetrusor injection of onabotulinum A toxin (BTX-A) is an effective regimen for the highly prevalent condition in women of overactive bladder. The optimal dose of BTX-A has not been definitively established. Women (n = 13) with overactive bladder including urge incontinence refractory to at least two different oral/transdermal anticholinergic regimens and who had idiopathic detrusor overactivity were randomized to 100-unit and 200-unit doses utilizing a double-blinded crossover design. One woman (100-unit dose) experienced prolonged urinary retention. For the remaining patients, quality of life parameters estimated using the overactive bladder questionnaire baseline showed no significant difference between either dose regimen at 3, 6, 9 and 12 months follow up. Urodynamic data were recorded at (pre-treatment) and at 3 months after each treatment. Mean (SD) volume at first leakage was 178 (82) ml and 327 (115) ml for 200 units and 226 (131) ml and 215 (139) ml for 100 units (p < 0.001). Significant differences (p < 0.05) between baseline and 3 months in favour of the 200-unit dose were also observed in bladder capacity; volume at first urgency sensation; volume at first detrusor contraction. Changes in voiding parameters between baseline and 3 months for maximal flow rate, maximal detrusor pressure, and post-void residual volume were not significantly different for the two doses. Mean (SD) maximal voided volumes recorded on the patients' bladder diaries were 178 (82) ml and 327 (115) ml for 200 units and 226 (131) ml and 215 (139) ml for 100 units (p < 0.001). The following bladder diary parameters were not significantly different: daytime frequency; nocturia; incontinence episodes. Thus, for the subset of women with idiopathic detrusor overactivity, although urodynamic parameters suggest 200 units to be superior, this did not translate to any clinically meaningful improvement over 100 units.