Will suburothelial injection of small dose of botulinum A toxin have similar therapeutic effects and less adverse events for refractory detrusor overactivity?

Objectives. To investigate whether suburothelial injection of different doses of botulinum A toxin (BTX-A) will have a similar therapeutic effect but fewer adverse events than 200 U BTX-A in patients with refractory detrusor overactivity. Methods. A total of 75 patients with detrusor overactivity refractory to anticholinergics were enrolled and randomized to receive 100, 150, or 200 U of BTX-A injected into the suburothelial space at 40 sites. Urinary incontinence was graded on a self-reported scale of 0 to 3, representing continence and mild, moderate and severe incontinence, respectively. The therapeutic effects, adverse events, and urodynamic parameters were assessed at 3 months. Results. An excellent result at 3 months was obtained in 34.8%, 36%, and 40.7% of patients treated with 100, 150, and 200 U of BTX-A, respectively. The patients who received 100 U of BTX-A had a lower incidence of a large postvoid residual urine volume (150 mL or more) than did those who received 150 or 200 U (30.4% versus 52% and 72%, respectively, P = 0.01 1) after treatment. The posttreatment urodynamic parameters were similar between the patients who received 150 or 200 U of BTX-A, but the changes in bladder capacity and postvoid residual urine volume were greater than those for the patients who received 100 U. The duration of therapeutic effectiveness was significantly shorter for the patients treated with 100 U compared with that for those treated with 150 or 200 U of BTX-A. Conclusions. Suburothelial injection of 100 U of BTX-A achieved a similar rate of excellent results and had significantly fewer adverse events compared with 150 or 200 U.,The dose of suburothelial BTX-A also affected the duration of therapeutic effectiveness.