BACKGROUND: The role of intravesical botulinum toxin A (BTX-A) injections in bladder pain syndrome/interstitial cystitis (BPS/IC) has not been clearly defined. The aim of this study was to evaluate high-level evidence regarding the efficacy and safety of BTX-A injections for BPS/IC.

MATERIAL AND METHODS: We conducted a comprehensive search of PubMed, Embase, and Web of Science, and conducted a systematic review and meta-analysis of all available randomized controlled trials (RCTs) and controlled studies assessing BTX-A injections for BPS/IC.

RESULTS: Seven RCTs and 1 retrospective study were identified based on the selection criteria. Pooled analyses showed that although BTX-A was associated with a slightly larger volume of post-void residual urine (PVR) (weighted mean difference [WMD] 10.94 mL; 95% confidence intervals [CI] 3.32 to 18.56; p=0.005), patients in this group might benefit from greater reduction in pelvic pain (WMD –1.73; 95% CI –3.16 to –0.29; p=0.02), Interstitial Cystitis Problem Index (ICPI) scores (WMD –1.25; 95% CI –2.20 to –0.30; p=0.01), and Interstitial Cystitis Symptom Index (ICSI) scores (WMD –1.16; 95% CI –2.22 to –0.11; p=0.03), and significant improvement in daytime frequency of urination (WMD –2.36; 95% CI –4.23 to –0.49; p=0.01) and maximum cystometric capacity (MCC) (WMD 50.49 mL; 95% CI 25.27 to 75.71; p<0.00001). Nocturia, maximal urinary flow rate, dysuria, and urinary tract infection did not differ significantly between the 2 groups.

CONCLUSIONS: Intravesical BTX-A injections might offer significant improvement in bladder pain symptoms, daytime urination frequency, and MCC for patients with refractory BPS/IC, with a slightly larger PVR. Further well-designed, large-scale RCTs are required to confirm the findings of this analysis.

Keywords: Botulinum Toxins, Type A - therapeutic use, Administration, Intravesical, Case-Control Studies, Cystitis, Interstitial - physiopathology, Dysuria - physiopathology, Pain Measurement, Pelvic Pain - physiopathology, Publication Bias, Risk Factors, Urination