Hiprex for Recurring Urinary Tract Infections

Overseen By Philippe Zimmern, MD

Age: 18+

Sex: Female

Trial Phase: Phase 4

Sponsor: University of Texas Southwestern Medical Center

Must be taking: Hiprex

Must not be taking: Antibiotics

Disqualifiers: Neurogenic bladder, Catheters, Uncontrolled diabetes, others

No Placebo Group All trial participants will receive the active study treatment (no placebo)

Prior Safety Data This treatment has passed at least one previous human trial

Compensation: Varies

Number of Visits: Unknown

Duration: 1 year

What You Need to Know Before You Apply

What is the purpose of this trial?

This trial explores the effectiveness of Hiprex in reducing frequent urinary tract infections (UTIs) in women. Researchers aim to determine if the medication can lower the number of UTIs over time by monitoring a substance in the urine. Women who have experienced at least two UTIs in the past six months or three in the past year are suitable candidates for this study. As a Phase 4 trial, Hiprex is already FDA-approved and proven effective, and this research seeks to understand how it benefits more patients.

Will I have to stop taking my current medications?

The trial requires that you are not on antibiotics at the start, but it does not specify about other medications. If you are taking antibiotics, you would need to stop them before joining the trial.

What is the safety track record for Hiprex?

Research has shown that Hiprex is generally safe and effective for individuals with frequent urinary tract infections (UTIs). Studies have found that methenamine hippurate, the main ingredient in Hiprex, helps prevent UTIs and is considered safe, as it typically does not cause serious side effects for most people.

A review indicates that methenamine is a good option for managing UTIs without heavily relying on antibiotics, which benefits patients requiring long-term treatment to prevent infections. Specifically, another study found that it reduces the need for antibiotics and hospital visits for those with frequent UTIs.

Overall, Hiprex appears to be a safe and effective choice for managing frequent UTIs. ^{1 2 3 4 5}

Why are researchers enthusiastic about this study treatment?

Unlike the standard antibiotics used to treat urinary tract infections (UTIs), Hiprex offers a unique approach by preventing bacterial growth through its active ingredient, methenamine. Methenamine works by turning into formaldehyde in the acidic environment of the urine, providing an antiseptic effect that can help manage recurring infections. Researchers are excited about Hiprex because it offers a different mechanism of action that may reduce the need for continuous antibiotic use, potentially minimizing antibiotic resistance and offering a long-term solution for those with chronic UTIs.

What is the effectiveness track record for Hiprex in treating recurring urinary tract infections?

Research has shown that Hiprex, containing methenamine hippurate, effectively prevents repeated urinary tract infections (UTIs). Studies have found it reduces UTIs in women by about 25%, comparable to low-dose antibiotics. Importantly, methenamine hippurate achieves this without antibiotics, helping to reduce antibiotic use. To ensure optimal results, maintaining acidic urine is crucial for the treatment's effectiveness. Overall, Hiprex is considered safe for long-term UTI prevention. Participants in this trial will receive Hiprex to evaluate its effectiveness in patients with both negative and positive urine cultures. ^{3 6 7 8 9}

Who Is on the Research Team?

Philippe Zimmern, MD

Principal Investigator

UT Southwestern Medical Center

Are You a Good Fit for This Trial?

This trial is for women aged 50-85 who have had at least two urinary tract infections in the last six months or three in the past year. They must be able to take Hiprex at home and speak English. Women with liver disease, allergies to Hiprex, uncontrolled diabetes, chronic renal failure, or those on antibiotics are excluded.

Inclusion Criteria

I am between 50 and 85 years old.

I am female.

I have had at least 2 UTIs in the last 6 months or 3 in the last year.

Exclusion Criteria

Inability to take Hiprex reliably at home, such as having psychosis, dementia, or swallowing disorders

I have a history of liver disease.

I have a condition that affects how my bladder functions.

Timeline for a Trial Participant

Screening

Participants are screened for eligibility to participate in the trial

2-4 weeks

Treatment

Participants receive Methenamine Hippurate (Hiprex™) to measure formaldehyde concentration and evaluate its effects on recurrent urinary tract infections

1 year

Follow-up

Participants are monitored for safety and effectiveness after treatment

1 year

What Are the Treatments Tested in This Trial?

Interventions

• Hiprex

Trial Overview The study tests how effective Methenamine Hippurate (Hiprex) is for women with recurring UTIs by measuring formaldehyde levels in urine and observing if it reduces infection rates over time when taken under proper conditions.

How Is the Trial Designed?

Group I: Group 1 - Patients with negative and positive urine culture Experimental Treatment 1 Intervention

Who Is Running the Clinical Trial?

University of Texas Southwestern Medical Center

Lead Sponsor

Trials

1,102

Recruited

1,077,000+

Published Research Related to This Trial

Antibacterials used to treat urinary tract infections commonly cause gastrointestinal side effects, which can result from various mechanisms such as irritation of the bowel and changes in gut flora.

Among the treatments reviewed, beta-lactams, nitrofurantoin, and fosfomycin are considered relatively safe, as they have a low incidence of serious toxicity despite causing some minor side effects.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

A perspective on the safety of antibacterials used to treat urinary tract infections. Reeves, DS.[2019]

In a study of 20 girls aged 5-12 with recurrent urinary tract infections, treatment with methenamine hippurate (Hiprex) for 12 months significantly reduced the average number of infections from 3.1 to 0.7 per year (p < 0.001).

After stopping the treatment, the infection rate increased to 1.4 per year, indicating that methenamine hippurate is effective for long-term prevention of urinary tract infections, with minimal side effects reported.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

Long-term prophylaxis with methenamine hippurate in girls with recurrent urinary tract infections. Petersen, S.[2019]

Citations

1. bmcurol.biomedcentral.com bmcurol.biomedcentral.com/articles/10.1186/s12894-025-01708-8

Effectiveness of methenamine hippurate in preventing urinary ... Conclusions. Overall, our meta-analysis provides evidence supporting methenamine hippurate as an effective, non-inferior and safe prophylactic ...

2. pmc.ncbi.nlm.nih.gov pmc.ncbi.nlm.nih.gov/articles/PMC10098264/

Methenamine hippurate to prevent recurrent urinary tract ... The benefit of the study is potentially large for older women with recurrent UTIs, resulting in fewer UTI episodes, reduced antibiotic usage and ...

3. sciencedirect.com sciencedirect.com/science/article/abs/pii/S1198743X25003441

Methenamine hippurate as prophylaxis for recurrent ... Methenamine hippurate reduces the frequency of rUTIs in older women with a point estimate of a 25% reduction, suggesting advantages over low-dose antibiotic ...

4. evidence.nihr.ac.uk evidence.nihr.ac.uk/alert/methenamine-as-good-as-antibiotics-preventing-urinary-tract-infections/

Methenamine is as good as antibiotics at preventing UTIs “This was the first study to robustly demonstrate that a non-antibiotic, methenamine, can prevent recurrent urinary tract infections in women.

5. tandfonline.com tandfonline.com/doi/full/10.1080/17512433.2024.2445621

Full article: Methenamine Hippurate in UTI management If effective, MH is generally considered safe for long-term use in preventing rUTIs. Maintaining acidic urinary pH for optimal outcome is important hence ...

6. pmc.ncbi.nlm.nih.gov pmc.ncbi.nlm.nih.gov/articles/PMC6551271/

Safety and Efficacy of Methenamine Hippurate for the ... We found that methenamine is well tolerated and is useful in reducing UTI, antibiotic prescriptions, and hospitalization in RTR with recurrent UTI.

7. webmd.com webmd.com/drugs/2/drug-6822/methenamine-hippurate-oral/details

Methenamine (Hiprex, Urex) - Uses, Side Effects, and More Methenamine is commonly used to prevent or reduce the chances of getting frequent kidney or bladder infections (urinary tract infections) that are caused by ...

8. accpjournals.onlinelibrary.wiley.com accpjournals.onlinelibrary.wiley.com/doi/10.1002/phar.2895

Methenamine for urinary tract infection prophylaxis: A ... This systematic review suggests methenamine generally appears to be an effective and well-tolerated antibiotic-sparing option for UTI prophylaxis.

9. reference.medscape.com reference.medscape.com/drug/hiprex-methenamine-342580

Hiprex, Mandelamine (methenamine) dosing, indications ... Indicated for prophylactic or suppressive treatment of frequently recurring urinary tract infections when long-term therapy is considered necessary.