Intradetrusor Botulinum Toxin A for OAB Via 1 Versus 10 Injections: A Randomized Clinical Trial

February 6, 2026 updated by: Carly Ann Crowder, University of California, Irvine
Patients with either overactive bladder (OAB) or urgency urinary incontinence (UUI) with be randomized (like a flip of a coin) to receive 100 units of bladder Botox® at either one injection site or ten injection sites. Efficacy and patient satisfaction will be measured by questionnaires.

Study Overview

Status

Completed

Conditions

Intervention / Treatment

Detailed Description

Intradetrusor (bladder) Botulinum toxin A (BTA or Botox®) is a well-established treatment for urinary urgency incontinence (UUI).[1,2] While this treatment's efficacy in comparison to alternative therapies including anticholinergic medications and sacral neuromodulation for treatment of UUI has been studied, the ideal number of injection sites within the bladder has not been well established. [3,4] Intradetrusor BTA injections are often completed as an office procedure while the patient is awake. Each injection site can cause discomfort for the patient during the procedure. Urinary tract infection and urinary retention are risks associated with this procedure and could potentially be related to number of injection sites. Currently, there is a lack of information in the literature regarding the optimal number of intravesical BTA injection sites.

Prior studies evaluated efficacy using 100u BTA spread across 20 injections sites, however current practices at local institutions safely use 10 injections sites based on studies showing similar effect and adverse event profiles between use of 10, 20, and 40 injection sites.[5,6] Research using animal models has shown diffuse distribution of BTA within the entire detrusor muscle after just a single BTA injection at one site.[7] This has been corroborated in human studies.[8] A recently published observational pilot study shows promise for single site intradetrusor Botox® injection as it reported a lower rate of urinary retention and similar durability.[9] Similar clinical efficacy with only one to three intravesical BTA injection[s] has also been reported.[10]

In this study, participants will be randomized to receive 100u BTA via intradetrusor injection at one injection site (experimental) versus 10 injection sites (control). Investigators hypothesize that one injection will have similar efficacy to multiple injections and potentially better tolerability and patient satisfaction, due to decreased procedure time and less pain, along with potential for lower adverse event rates, specifically urinary retention and urinary tract infections.

Study Type

Interventional

Enrollment (Actual)

116

Phase

  • Phase 4

Contacts and Locations

This section provides the contact details for those conducting the study, and information on where this study is being conducted.

Study Locations

  • United States
    • California
      • Orange, California, United States, 92868
        • University of California Irvine Medical Center

Participation Criteria

Researchers look for people who fit a certain description, called eligibility criteria. Some examples of these criteria are a person's general health condition or prior treatments.

Eligibility Criteria

Ages Eligible for Study

18 years and older (Adult, Older Adult)

Accepts Healthy Volunteers

Yes

Description

Inclusion Criteria:

  • Female
  • 18 years old or greater
  • Diagnosis of overactive bladder (urinary urgency or frequency, OAB) or urinary urgency incontinence (UUI)

Exclusion Criteria:

  • Have a diagnosis of neurogenic bladder
  • Received intravesical botox injections within prior 6 months
  • Current treatment with either: SNM, PTNS, or OAB medications - need wash out as below
  • SNM - turn device off for at least 2 weeks prior to procedure, off during 3-month follow up window
  • PTNS - no treatments within 2 weeks of start, none during 3-month post-procedure follow up window
  • OAB meds - 2 week wash out period prior to injection, none during 3-month post-procedure follow up window
  • Currently pregnant or trying to get pregnant
  • Contraindications to Botox® - hypersensitivity to Botox®, inability to self-catheterize/refusal to have indwelling catheter
  • Have a UTI (can enroll after treatment)
  • Have urinary retention (PVR>150cc on two occasions)
  • Do not speak English or Spanish

Study Plan

This section provides details of the study plan, including how the study is designed and what the study is measuring.

How is the study designed?

Design Details

  • Primary Purpose: Treatment
  • Allocation: Randomized
  • Interventional Model: Parallel Assignment
  • Masking: Single

Arms and Interventions

Participant Group / Arm
Intervention / Treatment
Experimental: 1 Injection Site
100u Botox® injected at one intradetrusor site
Drug: OnabotulinumtoxinA 100 UNT [Botox]
Intradetrusor (Bladder) Botox Injection at 1 vs 10 injection sites
Active Comparator: 10 Injection Sites
100u Botox® injected at 10 intradetrusor sites
Drug: OnabotulinumtoxinA 100 UNT [Botox]
Intradetrusor (Bladder) Botox Injection at 1 vs 10 injection sites

What is the study measuring?

Primary Outcome Measures

Outcome Measure
Measure Description
Time Frame
Change in Overactive Bladder Questionnaire Long Form Score (Symptoms Severity Sub-scale)(OAB-Q LF)
Time Frame: change from baseline OAB-Q score to 3 wk post-procedure score

Participants will be asked to Overactive Bladder Questionnaire Long Form prior to receiving the Botox procedure. The OAB-Q LF symptom severity sub-scale score will be compared prior to procedure and again to score at 3 weeks after procedure.

The OAB-q Symptom Severity Score will be computed at baseline and 3 weeks (and 3 months) using the standard scoring algorithm. Minimum value of symptom severity subscale is 8, maximum is 48. A higher score means worse symptoms. A lower score means less symptoms.
change from baseline OAB-Q score to 3 wk post-procedure score

Secondary Outcome Measures

Outcome Measure
Measure Description
Time Frame
Post-void Residual (PVR)
Time Frame: PVR collected at 3 wk post-procedure
A PVR will be collected via either urethral catheterization or bladder scan (ultrasound in clinic) at 3 weeks post-procedure as a marker of urinary retention. The PVRs will be compared between study and control groups
PVR collected at 3 wk post-procedure
Number of Participants With Urinary Tract Infection (UTI)
Time Frame: anytime after procedure, until at least 3 months post-procedure.
Urine culture will be sent for any patient with urinary tract infections symptoms (eg: worsening urgency, frequency, dysuria).
anytime after procedure, until at least 3 months post-procedure.
Change in Overactive Bladder Questionnaire Long Form Score (Health Related Quality of Life)(OAB-Q LF HRQL Subscale)
Time Frame: comparison of baseline OAB-Q HRQL score to 3 month post-procedure score
Participants will be asked to complete Overactive Bladder Questionnaire Long Form prior to receiving the Botox procedure. The OAB-Q LF HRQL sub-scale score will be compared prior to procedure and again to score at 3 months after procedure. The score range for the OAB-Q LF HRQL score is 0-100. An increased score equates to improvement in quality of life. A positive change equates to improvement in quality of life. A negative change equates to decreased quality of life.
comparison of baseline OAB-Q HRQL score to 3 month post-procedure score
Number of Patients With Patient Global Impression - Improvement (PGI-I) Score of 1
Time Frame: 3 months after botox procedure
Participants will complete PGI-I Questionnaire at 3 months after procedure. The minimum value is 1 (very much better) and maximum value score is 7 (very much worse). A higher score indicates worse symptoms. A lower score indicates better symptoms or more improvement.
3 months after botox procedure
Visual Analogue Scale (VAS) - Pain
Time Frame: immediately after procedure
Participants will complete VAS-pain immediately post-procedure as a pain and tolerability assessment. Score on a scale of (0-100) with 0 being no pain and 100 being highest level of pain.
immediately after procedure

Collaborators and Investigators

This is where you will find people and organizations involved with this study.

Sponsor

University of California, Irvine

Collaborators

Kaiser Permanente
St. Joseph Hospital of Orange

Investigators

  • Principal Investigator: Carly Crowder, MD, UC Irvine
  • Study Director: Taylor Brueseke, MD, UC Irvine
  • Study Chair: Felicia Lane, MD, UC Irvine

Publications and helpful links

The person responsible for entering information about the study voluntarily provides these publications. These may be about anything related to the study.

General Publications

Study record dates

These dates track the progress of study record and summary results submissions to ClinicalTrials.gov. Study records and reported results are reviewed by the National Library of Medicine (NLM) to make sure they meet specific quality control standards before being posted on the public website.

Study Major Dates

Study Start (Actual)

May 1, 2022

Primary Completion (Actual)

December 31, 2023

Study Completion (Actual)

March 31, 2024

Study Registration Dates

First Submitted

March 15, 2022

First Submitted That Met QC Criteria

March 24, 2022

First Posted (Actual)

April 4, 2022

Study Record Updates

Last Update Posted (Actual)

February 25, 2026

Last Update Submitted That Met QC Criteria

February 6, 2026

Last Verified

February 1, 2026

More Information

Terms related to this study

Additional Relevant MeSH Terms

Other Study ID Numbers

  • 309

Plan for Individual participant data (IPD)

Plan to Share Individual Participant Data (IPD)?

NO

Drug and device information, study documents

Studies a U.S. FDA-regulated drug product

Yes

Studies a U.S. FDA-regulated device product

No

product manufactured in and exported from the U.S.

Yes

This information was retrieved directly from the website clinicaltrials.gov without any changes. If you have any requests to change, remove or update your study details, please contact register@clinicaltrials.gov. As soon as a change is implemented on clinicaltrials.gov, this will be updated automatically on our website as well.

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