A Multicenter Randomized Cross-Over Study Evaluating the Efficacy and Safety of Silodosin in Adult Women With Voiding Dysfunction

September 10, 2026 updated by: Said Yaiesh, Jaber Al Ahmad Al Sabah Hospital

Background Voiding dysfunction in adult women is a clinically significant condition associated with impaired quality of life and limited evidence-based pharmacological treatment options. Selective α1A-adrenergic antagonists such as silodosin may reduce urethral resistance and improve voiding efficiency; however, robust randomized data in women remain limited. This study addresses the need for high-quality evidence in this population.

Objectives To evaluate the efficacy and safety of silodosin compared to placebo in adult women with voiding dysfunction using a randomized cross-over study design.

Methods This is a prospective, multicenter, randomized, placebo-controlled cross-over study conducted at Ministry of Health hospitals in Kuwait. Adult women aged 21 years and older with clinically diagnosed voiding dysfunction will be enrolled. Participants will receive silodosin and placebo in a randomized sequence, separated by a washout period. Each participant will serve as her own control.

Expected Results / Conclusions The study is expected to clarify the role of silodosin in improving voiding symptoms in adult women and to provide safety data to guide future clinical practice.

Study Overview

Status

Not yet recruiting

Conditions

Intervention / Treatment

Detailed Description

Background:

Female voiding dysfunction and non-neurogenic lower urinary tract symptoms (LUTS) represent a common yet under-recognized clinical problem that significantly impacts quality of life. Symptoms may include hesitancy, straining, weak urinary stream, prolonged voiding time, and a sensation of incomplete bladder emptying. Despite their prevalence, diagnostic pathways and management strategies in women remain heterogeneous and less well standardized compared to male populations. Current international guidance highlights the complexity of female LUTS and emphasizes the need for better characterization and evidence-based treatment strategies, particularly for voiding-predominant symptoms and functional bladder outlet obstruction [1].

The European Association of Urology (EAU) guidelines on female non-neurogenic LUTS underscore that female voiding dysfunction is multifactorial and often underdiagnosed, with limited high-quality evidence guiding pharmacological management [1]. Similarly, contemporary reviews and International Continence Society (ICS) discussions have highlighted substantial gaps in clinical trials addressing female voiding dysfunction, particularly interventional studies evaluating medical therapies targeting urethral and bladder outlet mechanisms [2,3].

Alpha-adrenergic receptors, particularly the α1A subtype, play an important role in urethral smooth muscle tone. Pharmacological blockade of these receptors has a well-established role in male lower urinary tract symptoms. In women, emerging evidence suggests that alpha-blockers may reduce functional urethral resistance and improve voiding efficiency; however, available data remain limited and heterogeneous. A systematic review and meta-analysis evaluating alpha-blocker use in women with LUTS demonstrated potential symptom improvement but emphasized variability in study design, patient selection, and outcome measures, reinforcing the need for well-designed randomized trials [4]. Additional systematic reviews have similarly reported modest benefits of alpha-blockers in selected female populations, while calling for higher-quality evidence to guide routine clinical use [5].

Non-neurogenic female bladder outlet obstruction and voiding dysfunction remain challenging clinical entities, with recent reviews highlighting the lack of standardized therapeutic pathways and the reliance on extrapolated evidence from male studies [6]. These reviews consistently identify selective alpha-blockade as a promising but insufficiently studied therapeutic option, particularly in women without overt anatomical obstruction.

Silodosin is a highly selective α1A-adrenergic receptor antagonist with a favorable pharmacological profile and established safety record. Recent prospective studies have explored the use of silodosin in women with lower urinary tract and voiding symptoms, suggesting potential improvements in symptom scores and voiding parameters, with acceptable tolerability [7]. Additional studies evaluating silodosin, either alone or in combination with other agents, have further supported its potential role in female LUTS management, though these studies remain limited by sample size, study design, or focus on storage-predominant symptoms [8]. Emerging abstracts and presentations at international continence meetings have continued to highlight growing clinical interest in silodosin for female voiding dysfunction, while reinforcing the need for rigorous randomized controlled trials [7-11].

Given the persistent evidence gaps, the absence of standardized pharmacological treatment for female voiding dysfunction, and the promising yet inconclusive data surrounding selective alpha-blockade, there is a clear need for a well-designed randomized clinical study. A randomized cross-over, placebo-controlled design allows each participant to serve as her own control, minimizing inter-individual variability and reducing unnecessary drug exposure. This approach is particularly well suited for functional voiding disorders and aligns with ethical principles of participant safety and scientific rigor.

This multicenter randomized cross-over study aims to address these gaps by evaluating the efficacy and safety of silodosin in adult women with voiding dysfunction, thereby contributing robust evidence to inform clinical practice and future guideline development.

Aim & Objectives:

Aim: To assess the efficacy and safety of silodosin in adult women with voiding dysfunction.

Objectives:

  • To compare voiding symptoms during silodosin and placebo treatment periods
  • To assess patient-reported symptom improvement
  • To evaluate the safety and tolerability of silodosin
  • To compare outcomes between treatment sequences

Study Type

Interventional

Enrollment (Estimated)

150

Phase

  • Phase 2

Contacts and Locations

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

Study Contact

  • Name: Said M Yaiesh, BMBCh MSurg MSurgEd KBU
  • Phone Number: +96597964200
  • Email: syaiesh@hotmail.com

Study Contact Backup

  • Name: Tariq F Al-Shaiji, BMBCh FRCSC
  • Phone Number: +96599773789
  • Email: tshaiji@gmail.com

Study Locations

  • Kuwait
    • Kuwait
      • Kuwait City, Kuwait, Kuwait, 00000
        • Amiri Hospital
        • Contact:
        • Contact:
        • Principal Investigator:
          • Meshari F Almutairi, BMBCh KBU
      • Kuwait City, Kuwait, Kuwait, 00000
        • Farwaniya Hospital
        • Contact:
        • Contact:
        • Principal Investigator:
          • Awad Thahir, MD KBU
      • Kuwait City, Kuwait, Kuwait, 00000
        • Jaber Al Ahmad Al Jaber Al Sobah Hospital
        • Contact:
        • Contact:
        • Principal Investigator:
          • Said M Yaiesh, BMBCh

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

  • Adult
  • Older Adult

Accepts Healthy Volunteers

No

Description

Inclusion Criteria:

Eligible participants must have clinically significant voiding symptoms including one or more of the following:

  • Difficulty initiating voiding
  • Slow urinary stream
  • Intermittent urinary stream
  • Straining to void
  • Sensation of incomplete bladder emptying

AND at least one objective parameter suggestive of impaired bladder emptying:

  • Post-void residual urine volume ≥100 mL
  • Maximum urinary flow rate (Qmax) <15 mL/sec with voided volume >150 mL
  • Abnormal pressure-flow findings where available"

Exclusion Criteria:

  • Pregnancy or breastfeeding
  • Active urinary tract infection
  • Neurogenic bladder dysfunction
  • Significant pelvic organ prolapse requiring intervention
  • Previous bladder outlet or urethral surgery
  • Severe renal or hepatic impairment

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: Crossover Assignment
  • Masking: Quadruple

Arms and Interventions

Participant Group / Arm
Intervention / Treatment
Experimental: Silodosin → Placebo
Participants will receive silodosin 8 mg orally once daily for 8 weeks, followed by a 2-week washout period, then matching placebo once daily for 8 weeks.
Drug: Silodosin 8 mg
Silodosin 8 mg oral capsule administered once daily for 8 weeks. In the crossover design, participants will receive silodosin during one treatment period and matching placebo during the alternate treatment period, separated by a 2-week washout period.
Drug: Placebo
Matching placebo oral capsule administered once daily for 8 weeks. The placebo will be identical in appearance and packaging to silodosin to maintain masking. Participants will receive placebo during one treatment period and silodosin during the alternate treatment period, separated by a 2-week washout period.
Experimental: Placebo → Silodosin
Participants will receive matching placebo orally once daily for 8 weeks, followed by a 2-week washout period, then silodosin 8 mg orally once daily for 8 weeks.
Drug: Silodosin 8 mg
Silodosin 8 mg oral capsule administered once daily for 8 weeks. In the crossover design, participants will receive silodosin during one treatment period and matching placebo during the alternate treatment period, separated by a 2-week washout period.
Drug: Placebo
Matching placebo oral capsule administered once daily for 8 weeks. The placebo will be identical in appearance and packaging to silodosin to maintain masking. Participants will receive placebo during one treatment period and silodosin during the alternate treatment period, separated by a 2-week washout period.

What is the study measuring?

Primary Outcome Measures

Outcome Measure
Measure Description
Time Frame
Change in Total International Prostate Symptom Score (IPSS) Following Treatment
Time Frame: Beginning and end of each 8-week treatment period (Weeks 0-8 and Weeks 10-18).
Change in total International Prostate Symptom Score (IPSS) from the beginning to the end of each 8-week treatment period. The IPSS consists of 7 symptom questions, each scored from 0 to 5, giving a total score ranging from 0 to 35, with higher scores indicating more severe lower urinary tract symptoms. The treatment effect of silodosin will be compared with that of placebo within the crossover design.
Beginning and end of each 8-week treatment period (Weeks 0-8 and Weeks 10-18).

Secondary Outcome Measures

Outcome Measure
Measure Description
Time Frame
Change in IPSS Voiding Subscore
Time Frame: Beginning and end of each 8-week treatment period (Weeks 0-8 and Weeks 10-18).
Change in the International Prostate Symptom Score (IPSS) voiding subscore from the beginning to the end of each 8-week treatment period. The voiding subscore comprises the IPSS items relating to incomplete emptying, intermittency, weak stream, and straining; higher scores indicate greater symptom severity.
Beginning and end of each 8-week treatment period (Weeks 0-8 and Weeks 10-18).
Change in Overactive Bladder Symptom Score (OABSS)
Time Frame: Beginning and end of each 8-week treatment period (Weeks 0-8 and Weeks 10-18).
Change in total OABSS from the beginning to the end of each 8-week treatment period. Higher scores indicate greater overactive bladder symptom severity.
Beginning and end of each 8-week treatment period (Weeks 0-8 and Weeks 10-18).
Change in Quality-of-Life Score
Time Frame: Beginning and end of each 8-week treatment period (Weeks 0-8 and Weeks 10-18).
Change in the IPSS quality-of-life score from the beginning to the end of each 8-week treatment period. The score ranges from 0 (delighted) to 6 (terrible), with higher scores indicating worse urinary symptom-related quality of life.
Beginning and end of each 8-week treatment period (Weeks 0-8 and Weeks 10-18).
Change in Post-Void Residual Urine Volume
Time Frame: Beginning and end of each 8-week treatment period (Weeks 0-8 and Weeks 10-18).
Change in post-void residual urine volume, measured in milliliters, from the beginning to the end of each treatment period.
Beginning and end of each 8-week treatment period (Weeks 0-8 and Weeks 10-18).
Change in Maximum Urinary Flow Rate (Qmax)
Time Frame: Beginning and end of each 8-week treatment period (Weeks 0-8 and Weeks 10-18).
Change in maximum urinary flow rate, measured by uroflowmetry in mL/second, from the beginning to the end of each treatment period.
Beginning and end of each 8-week treatment period (Weeks 0-8 and Weeks 10-18).
Adverse Events
Time Frame: Throughout each treatment period and through completion of the 18-week study.
Incidence and nature of adverse events occurring during treatment with silodosin and placebo, including assessment of severity and relationship to study treatment.
Throughout each treatment period and through completion of the 18-week study.
Patient Global Impression of Improvement (PGI-I)
Time Frame: End of each 8-week treatment period (Weeks 8 and 18).
Patient-reported overall improvement in urinary symptoms assessed using the Patient Global Impression of Improvement (PGI-I) scale at the end of each treatment period. The PGI-I is a 7-point scale ranging from 1 (very much better) to 7 (very much worse), with lower scores indicating greater perceived improvement.
End of each 8-week treatment period (Weeks 8 and 18).

Collaborators and Investigators

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

Sponsor

Jaber Al Ahmad Al Sabah Hospital

Investigators

  • Study Chair: Tariq F Al-Shaiji, BMBCh FRCSC, Jaber Al Ahmad Hospital
  • Principal Investigator: Said M Yaiesh, BMBCh MSurg MSurgEd KBU, Jaber Al Ahmad Hospital
  • Principal Investigator: Meshari F Almutairi, BMBCh KBU, Amiri Hospital

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

Helpful Links

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 (Estimated)

October 1, 2026

Primary Completion (Estimated)

October 1, 2027

Study Completion (Estimated)

December 1, 2027

Study Registration Dates

First Submitted

September 10, 2026

First Submitted That Met QC Criteria

September 10, 2026

First Posted (Actual)

September 16, 2026

Study Record Updates

Last Update Posted (Actual)

September 16, 2026

Last Update Submitted That Met QC Criteria

September 10, 2026

Last Verified

September 1, 2026

More Information

Terms related to this study

Keywords

Additional Relevant MeSH Terms

Other Study ID Numbers

  • 2026/3235

Plan for Individual participant data (IPD)

Plan to Share Individual Participant Data (IPD)?

NO

IPD Plan Description

Individual participant data are not currently planned for public sharing because of participant confidentiality, institutional data-governance requirements, and the absence of an approved data-sharing framework across participating study sites. Aggregate study results will be reported through scientific publication and presentation.

Drug and device information, study documents

Studies a U.S. FDA-regulated drug product

No

Studies a U.S. FDA-regulated device product

No

product manufactured in and exported from the U.S.

No

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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