Efficacy and Safety of Low-Dose Intravesical OnabotulinumtoxinA Injections in Female Patients With Detrusor Overactivity With Detrusor Underactivity

Purpose We assessed the effectiveness and safety of using intravesical onabotulinumtoxinA (onabotA; BOTOX) injection with a low dose (75 units) for treating urinary storage symptoms in patients with detrusor overactivity with detrusor underactivity (DODU) compared to using the standard 100 units of onabotA in patients with overactive bladder (OAB). Methods This ambidirectional study included 121 female patients who received intravesical onabotA injections at our hospitals. A total of 87 patients with OAB and 34 patients with DODU were reviewed using a 3-day voiding diary, uroflowmetry, and questionnaires including the International Prostate Symptom Score (IPSS), Overactive Bladder Symptom Score, and Patient Perception of Bladder Condition. Patients were evaluated at baseline, within 2 weeks of treatment, and beyond 3 months after treatment. Results Questionnaire scores of the DODU group demonstrated significant improvement in the short term, with a subsequent decline, but an overall improvement compared to baseline in the long term. Notably, the DODU group exhibited enhanced IPSS voiding scores after the treatment. In the OAB group, most questionnaire scores, excluding the IPSS voiding score, showed significant posttreatment improvement, which was sustained to some extent in the long term. Voiding diary parameters related to storage symptoms were enhanced in both groups. The maximum and mean flow rates decreased in the OAB group but increased in the DODU group, particularly in the short term (P=0.000). The postvoid residual volume increased in both groups after posttreatment, with a mitigated change in the long term. Safety assessments revealed manageable adverse events in both groups with comparable frequencies. Conclusions Low-dose intravesical onabotA for DODU demonstrated a relatively shorter duration of efficacy than OAB. Nonetheless, the treatment improved both storage and voiding symptoms in patients with DODU without significant adverse effects.