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NCT Number: NCT06940622

A Trial of D-mannose for the Prophylaxis of Recurrent Urinary Tract Infections

A randomized, double-blind, placebo-controlled, 12-month study to determine the effectiveness of D-mannose (2g daily) supplementation in rUTI (recurrent urinary tract infection) prevention in post-menopausal women.

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Key information

Age range

55 year–85 year

Sex eligibility

Female

Study type

Interventional

Phase

Not applicable

Primary location

University of Texas Southwestern Medical Center

Dallas, Texas, 75390, United States

Location status: Recruiting

Location contact

Philippe E Zimmern, MD

PRINCIPAL_INVESTIGATOR

Sonobia Garrett, BSHS

CONTACT

[email protected]

214-645-8787

CONTACT

[email protected]

About this study

The proposed study on D-mannose prophylaxis is designed to address a critical unmet medical need to improve the understanding and prevention of rUTI (recurrent urinary tract infection) in post-menopausal women, a population disproportionately affected by rUTI and understudied. The efficacy of D-mannose on preventing uncomplicated rUTI will be elucidated, and additional study measures (including urine culture and one-hour D-mannose test results) may help establish an ideal candidate for responding to daily D-mannose intake over time. The proposed study will follow CONSORT guidelines for randomized clinical trial studies.

Aim 1. Test the hypothesis that D-mannose provides effective rUTI prophylaxis in post-menopausal women over 6 months.

Aim 2. Test the hypothesis that D-mannose provides effective rUTI prophylaxis in post-menopausal women beyond 6 months and up to one year.

The overarching hypotheses are that (1) D-mannose will be found superior to placebo in preventing rUTI in post-menopausal women over 6 months as suggested by one prior RCT7 (Aim 1) and (2) D-mannose will remain effective for rUTI prophylaxis up to one year (Aim 2).

Ninety (90) women currently UTI-free and with a history of uncomplicated rUTI, defined as ≥ 2 symptomatic UTIs in 6 months or ≥ 3 symptomatic UTIs in 12 months, will be enrolled and randomized (2:1 ratio) to receive D-mannose (2g, i.e., 4 x 500mg capsules) or placebo daily for 12 months.

Who can participate

Healthy volunteers accepted: No

Only the study team can determine whether someone qualifies for participation.

Inclusion criteria

  • Female, post-menopausal, age ≥ 55 years old
  • Diagnosis of recurrent UTI, defined as ≥ 3 symptomatic culture-proven UTI episodes in 12 months or ≥ 2 in 6 months.
  • Currently free from a UTI determined based on absence of symptoms as determined by the UTI symptom assessment questionnaire79 and negative urine culture (<103 colony forming units per ml of urine).
  • Able to attend all follow-up appointments for the study.
  • A negative upper and lower urinary tract evaluation, including pelvic examination for pelvic organ prolapse (less than stage 2), measurement of post-void residual (less than 50 ml), and imaging (renal ultrasound and standing voiding cystourethrogram) to exclude kidney stone, hydronephrosis, reflux, or urethral diverticulum.

Exclusion criteria

  • Current use of D-mannose. Patients willing to stop taking D-mannose will be offered to join the trial after a 4-week wash-out period.
  • Complicated UTIs, including need for catheter drainage or intermittent catheterization, neurogenic bladder, bladder augmentation, or urinary diversion.
  • Ongoing supplement use (Box 1). Patients willing to stop taking the listed supplements will be offered to join the trial after a 4-week wash-out period.
  • Evidence of upper tract infection (pyelonephritis), including temperature higher than 38°C, flank/lumbar pain or tenderness
  • Diagnosis of interstitial cystitis or overactive bladder syndrome
  • Prophylactic antibiotics started in the last 3 months and unwilling to discontinue, or intention to start in the next 12 months
  • Use of Uromune or other vaccine approaches to reduce rUTI
  • Participation in a research study involving an investigational product in the past 12 weeks
  • Receipt of phage treatment
  • History of chronic diarrhea requiring regular therapy
  • Inability to swallow or known history of gastrointestinal malabsorption
  • History of recurrent vaginal yeast infections
  • Systemic disease precluding enrollment in this study (uncontrolled diabetes with HgA1C above 7, ongoing chemotherapy or immunotherapy, renal insufficiency [creatinine > 1.5 g/dl]), mental or cognitive impairment, weight loss diet requiring excessively large amounts of fluid intake, or other health-related specific diet).
  • Nursing home resident
  • BMI >40

Box 1 Supplements to avoid

  • Multi-Vitamins and Multi-Mineral capsules
  • Specific Vitamins or Minerals (e.g., Calcium, Citrical, Calcium Gummies, Vitamin A, D, Niacin, Pyridoxine, Selenium, Vitamin E, B6, Iron, Omega 3, D3, Magnesium, B-Complex, Women's Ultra MultiVitamin, GNC B-Complex, B-12, PreserVision Areds2, Vitamins D, B Pollen)
  • Probiotics
  • Cranberry Mannose or Cranberry Extract Weight loss products to avoid
  • Medifast
  • Vitafusion
  • OptiVin Products
  • Appetite Suppressants
  • Keto-Fuel

Treatment and study plan

D-mannose

Dietary Supplement

D-mannose (2g, i.e., 4 x 500mg capsules) daily for 12 months.

Placebo

Dietary Supplement

Placebo daily for 12 months.

Primary outcomes

  1. Failure rate

    Time frame: Through study completion, an average of 5 years

    To determine whether prophylaxis with D-mannose reduces the incidence of UTI episodes compared to placebo. "Failure rate," defined as having 2 UTIs in 6 months or 3 in one year.

Secondary outcomes

  1. Number of UTI antibiotic treatments

    Time frame: Through study completion, an average of 5 years

    To investigate if D-mannose reduces the need for antibiotic use due to recurrent UTIs (measured as number of antibiotic courses for symptomatic culture-proven UTI episodes) compared to placebo.

    Number of UTI antibiotic treatments during the 6 months of treatment. If the participant receives >1 antibiotic course for UTI without symptom relief, it is regarded as one episode and counted as one antibiotic treatment. If there has been an asymptomatic period of at least 14 days in between two UTI antibiotic courses, this will be regarded as a new antibiotic treatment.

  2. Symptom severity

    Time frame: Through study completion, an average of 5 years

    To investigate if D-mannose reduces the severity of UTI symptoms compared to placebo. Record symptom severity using a validated UTI symptom assessment questionnaire.

  3. Serious adverse events associated with D-mannose

    Time frame: Through study completion, an average of 5 years

    To determine the frequency of serious adverse events associated with D-mannose. Number of participants who experienced adverse events >= Grade 3, as defined by Common Terminology Criteria for Adverse Events by CTCA version 5.0.

Study contacts

Contact information is provided by the study sponsor or research team.

Jessica de Araujo Paula

CONTACT

[email protected]

2146458787

Meghan Leak

CONTACT

[email protected]

2146458787

Sponsors and collaborators

Lead sponsor

University of Texas Southwestern Medical Center

Other

Registry information

Official study title

A Randomized Controlled Trial of D-mannose for the Prophylaxis of Recurrent Urinary Tract Infections in Post-menopausal Women

Acronym: DmannoseRCT

Important dates

Study start
2025
Primary completion
2029
Study completion
2030
First posted
Apr 23, 2025
Registry last updated
Sep 22, 2025

OpenTrials presents study information sourced from ClinicalTrials.gov. The official registry record should be consulted for the latest information.

View the official ClinicalTrials.gov record (opens in a new tab)

This listing is for discovery and informational purposes only. It is not medical advice, does not guarantee that a study is recruiting, and does not determine eligibility. Contact the study team and a qualified healthcare professional when considering participation.

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