Intravesical Injection of OnabotulinumtoxinA (Botulinum Toxin Type A) in Japanese Patients With Refractory Overactive Bladder

Abstract

Background/aim: Botulinum toxin intravesical injection therapy (hereafter, botulinum therapy) is approved in Japan for treating urinary urgency, frequency, and urinary incontinence due to refractory overactive bladder or neurogenic bladder. Although botulinum therapy is classified as urinary incontinence surgery, it is minimally invasive, effective, and safe. However, there are few reports on the actual use of botulinum therapy and examination of its effects and side-effects. Herein, we report real-world data on botulinum therapy.

Patients and methods: Patients who received botulinum therapy for refractory overactive bladder at the Nara Medical University and affiliated facilities from May 2020 to May 2022 were enrolled. The patient background, treatment efficacy, and safety were retrospectively reviewed.

Results: Twenty-three cases of refractory overactive bladder (age: 68.4±14.1 years; 7 males, 16 females; 17 outpatient, 6 hospitalized) were enrolled. Pretreatment, the overactive bladder symptom score (OABSS) was 10.1±2.7, and post-void residual urine volume was 27.1±31.6 ml. Botulinum was administered once, twice, thrice, and four times in 11, eight, three, and one cases, respectively. OABSS decreased to 6.1±3.2 2 weeks after botulinum therapy (p<0.0001), and the effect persisted at 6.6±3.2 after 12 weeks (p<0.0001). Post-void residual urine volume increased to 74.6±79.2 ml after 2 weeks (p=0.0010), but subsequently improved to 33.9±42.0 ml after 12 weeks (p=0.0002). Adverse events included post-void residual urine volume of 200 ml or more in three patients (7.5%) and urinary retention grade 2 in two (5.0%).

Conclusion: Botulinum therapy is effective and relatively safe for refractory overactive bladders.

Keywords: Botulinum toxin type A; intravesical injection; refractory overactive bladder; urinary incontinence.