Efficacy and Mechanism of Action of Methenamine Hippurate (Hiprex™) in Women With Recurring Urinary Tract Infections.

Efficacy and Mechanism of Action of Methenamine Hippurate (Hiprex™) in the Management of Recurrent Urinary Tract Infections in Women

The purpose of this study is to measure the concentration of formaldehyde in the urine of women with recurrent urinary tract infections on Hiprex; and then, assuming its urinary presence is confirmed at the proper acid urinary pH, evaluate if such a therapy has favorable effects in decreasing the rate of recurrent urinary tract infections over time.

Study Overview

• Status: Terminated
• Conditions: Urinary Tract Infections
• Intervention / Treatment: Drug: Hiprex

• Study Type: Interventional
• Enrollment (Actual): 14
• Phase: Phase 4

Contacts and Locations

Study Locations

• United States
  • Texas
    • Dallas, Texas, United States, 75390
      • UT-Southwestern Medical Center

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: 50 years to 85 years (Adult, Older Adult)
• Accepts Healthy Volunteers: No

Description

Inclusion Criteria:

1. Female
2. Age 50 - 85
3. Have RUTIs (at least 2 UTIs within the past 6 months or 3 within the past year) -

Exclusion Criteria:

1. Being on antibiotics at baseline (i.e. suppressive therapy or antibiotic therapy for urinary or non-urinary infections)
2. Neurogenic bladder condition
3. Using urinary catheters (including Foley catheter, intermittent catheterization, and suprapubic catheter)
4. Uncontrolled diabetes (HbA1c > 9)
5. Chronic renal failure defined as serum creatinine > 1.5 mg/dL
6. History of liver disease
7. Patients from out of town, in whom follow-up will not be possible
8. Pregnancy
9. Allergy to Hiprex
10. Inability to take Hiprex reliably at home, such as having psychosis, dementia, or swallowing disorders
11. Non-English speakers -

Study Plan

How is the study designed?

Design Details

• Primary Purpose: Treatment
• Allocation: N/A
• Interventional Model: Single Group Assignment
• Masking: None (Open Label)

Number of Arms

1

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
Experimental: Group 1 - Patients with negative and positive urine culture	Drug: Hiprex; Patients with negative urine culture will be prescribed Hiprex 1 g PO BID x 1 yr and patients with a positive urine culture will be prescribed antibiotics.; Other Names: Methenanime hippurate

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Number of Urinary Tract Infections	It would be measured by counting the positive urine cultures, or UTI-like episodes requiring antibiotic treatment during the 1 year of the study period.	1 year

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Frequency of Oral Antibiotic Use	Total number of calendar days on which a participant received one or more doses of an oral antibiotics	1 year
Number of Participants That Used Oral Anti-biotic	Number of participants who used oral-antibiotics to treat symptomatic UTI episodes during 1 year of Hiprex administration	1 year
Number of Hospital Re-admissions at 1 Year	Number of hospital re-admissions at 1 year due to urosepsis and pyelonephritis.	1 year
Frequency and Severity of Adverse Events Related to Hiprex	Number of participants who experienced adverse events >= Grade 3, as defined by Common Terminology Criteria for Adverse Events by CTCA version 5.0	1 year
Urine Acidity Levels	Urine acidity levels will be measured by urinary pH at each visit. Lower pH will yield a better outcome.	1 year
Number of Urinary Tract Infection Episodes	Number of UTI episodes will be measured for this outcome.	up to 1 year
Number of Urinary Tract Infection Episodes	Number of UTI episodes will be measured for this outcome.	up to 2 years
Severity of UTI Symptoms as Measured by the UTI Symptom Assessment Questionnaire	UTI Symptom Assessment questionnaire measures severity of UTI symptoms. Possible score range from 0 to 3 (0= Did not have 1= Mild 2=Moderate, and 3=Severe), higher score indicates higher severity of UTI symptoms	1 year
Duration of Intervals Between UTI Episodes	Duration of intervals will be measured between one UTI episode to the next UTI episode	1 year

Collaborators and Investigators

• Sponsor: University of Texas Southwestern Medical Center
• Investigators: Principal Investigator: Philippe Zimmern, MD, University of Texas Southwestern Medical Center

Study record dates

Study Major Dates

• Study Start (Actual): January 4, 2021
• Primary Completion (Actual): December 31, 2024
• Study Completion (Actual): December 31, 2024

Study Registration Dates

• First Submitted: December 17, 2020
• First Submitted That Met QC Criteria: January 12, 2021
• First Posted (Actual): January 14, 2021

Study Record Updates

• Last Update Posted (Actual): February 24, 2026
• Last Update Submitted That Met QC Criteria: February 9, 2026
• Last Verified: February 1, 2026

More Information

Terms related to this study

• Additional Relevant MeSH Terms: Urogenital Diseases; Male Urogenital Diseases; Urologic Diseases; Female Urogenital Diseases; Female Urogenital Diseases and Pregnancy Complications; Infections; Urinary Tract Infections; methenamine hippurate
• Other Study ID Numbers: STU-2020-0725

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.: No