Repeat intradetrusor injections of onabotulinum toxin a for refractory idiopathic overactive bladder patients: a single-center experience.

Objectives: : The objective of the study was to evaluate the safety and efficacy of repeat intradetrusor onabotulinum toxin A injection in patients with idiopathic overactive bladder refractory to anticholinergic medications. Furthermore, 2 doses, 100 and 150 U, were compared.

Methods: : We prospectively enrolled 60 patients in our investigator-initiated, single-center randomized trial. Thirty patients were randomized to each dosage arm. Total study duration was 3 years. Patients were eligible to receive 6 onabotulinum toxin A injections. Subjects completed a 3-day voiding diary and Urogenital Distress Inventory 6 (UDI-6) questionnaire and graded their quality of life on a visual analog scale (VAS) before study enrollment and at week 6 after every injection. The outcome was based on the amount of improvement noted on the UDI-6 and VAS scores at 6 weeks post every injection as compared with study enrollment.

Results: : There were 9 men and 51 women. The mean UDI-6 and VAS scores improved significantly (P = 0.0001) at week 6 after initial onabotulinum toxin A injection, and no change was seen when comparing repeat injections; 20% and 10% of the patients randomized to 150 and 100 U required performing clean intermittent catheterization, respectively. The mean UDI-6 scores after repeat onabotulinum toxin A injections did not differ significantly between 100 and 150 U.

Conclusions: : Repeat injections of onabotulinum toxin A are capable of significantly improving UDI-6 scores and quality of life in refractory patients with idiopathic overactive bladder. There was no evidence of decreased efficacy after repeat injections. Lower clean intermittent catheterization rates were noted in patients randomized to 100 U as compared with 150 U. Both doses, 100 and 150 U, were equally efficacious.