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Study of methenamine hippurate compared to a drug combination for preventing recurrent urinary tract infections in women

Verified siteRegistered drugNo placebo
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What is this trial about?

A plain-language summary of the goals, design and what participants do

This study focuses on women who experience recurrent urinary tract infections, which are frequent infections in the urinary system. The goal of the study is to determine if using methenamine hippurate as a way to prevent these infections is an effective alternative to using traditional antibiotics. Antibiotics are medicines used to kill bacteria, but using them frequently can sometimes lead to antimicrobial resistance, a situation where bacteria change so that the medicine no longer works against them.

Participants in the study will be assigned to receive different treatments to prevent further infections. One group will receive methenamine hippurate, while other groups will receive standard antibiotic treatments such as cefalexin, sulfamethoxazole and trimethoprim, or fosfomycin trometamol. These medications are taken by mouth over a period of time to see which method is better at reducing the number of symptomatic infection episodes and preventing the growth of multidrug-resistant bacteria, which are germs that are difficult to kill with standard medicines.

The research process

The trial runs in 3 steps – from screening to follow-up. Each step says what happens and what the team monitors.

  1. Step 1

    Start of the prophylaxis period

    The 6-month prophylaxis period begins, which is a period of preventive treatment to reduce the frequency of recurrent urinary tract infections (infections of the urinary system).

    One of two types of preventive treatment is assigned: the test treatment or a comparator treatment.

  2. Step 2

    Administration of preventive treatment

    If assigned the test treatment, methenamine hippurate (2 grams) is taken orally.

    If assigned a comparator treatment, one of the following options is used: cefalexin (500 milligrams) taken orally, septrin (400 milligrams of sulfamethoxazole and trimethoprim) taken orally as a tablet, or fosfomycin trometamol (0.42 grams) taken orally.

  3. Step 3

    Monitoring and follow-up

    During the initial 6-month treatment period, the number of symptomatic urinary tract infection episodes is monitored.

    The presence of multidrug-resistant profiles (bacteria that are difficult to kill with standard medicines) is also assessed.

    After the treatment period ends, a 12-month follow-up is conducted to monitor the number of symptomatic urinary tract infection episodes and any occurrences of severe infection episodes, such as urosepsis (a serious infection spreading from the urinary tract) or septic shock (a life-threatening condition caused by infection), as well as hospitalizations or bacteremia (the presence of bacteria in the blood).

Who can join the trial?

8 criteria

  • You must be a woman.
  • You must be between the ages of 18 and 85 years.
  • You must have recurrent urinary tract infections, which means you have frequent bladder or kidney infections.
  • To qualify, you must be starting antibiotic prophylaxis, which is a treatment where medicine is taken regularly to prevent infections from happening.
  • You must have had at least two or more urinary tract infection episodes in the last 6 months.
  • Alternatively, you must have had at least three or more urinary tract infection episodes in the last year.
  • Alternatively, you can qualify if you had fewer than three infections in the last year but experienced one or more severe episodes that required you to stay in the hospital.
  • You must provide written informed consent, which means you have read all the study information and signed a document agreeing to participate.

Who cannot join the trial?

11 criteria

  • Being pregnant or planning to become pregnant during the 12 months after joining the study.
  • Thinking you will not be able to finish the full 12-month follow-up period, which is the time when doctors check on your progress.
  • Having any health problem that the doctor believes might make it hard to see if the treatment is working or might prevent you from finishing the study.
  • Currently breastfeeding.
  • Having anatomical abnormalities of the urinary tract, which means the physical shape or structure of your bladder or the tubes that carry urine is not normal.
  • Using any urinary devices, such as a bladder catheter (a tube used to drain urine from the bladder) or a nephrostomy (a tube placed through the skin into the kidney to drain urine).
  • Having chronic renal failure, which is long-term kidney damage, with a glomerular filtration rate (GFR) below 40 mL/min. The GFR is a measurement used to check how well your kidneys are filtering waste from your blood.
  • Having hepatic cirrhosis, which is serious scarring of the liver, specifically categorized as Child–Pugh class B or C, which are scales used to measure the severity of liver disease.
  • Having hyperuricemia, which means having too much uric acid in your blood, or having a history of gout attacks, which is a type of painful swelling caused by uric acid crystals in the joints.
  • Taking regular medicine to change the acidity of your body or stomach, such as alkalinizing agents (medicines that make body fluids less acidic) or antacids (medicines that reduce stomach acid), including sodium bicarbonate, citrates, almagate, acetazolamide, or other carbonic anhydrase inhibitors (a specific type of medicine that affects how your body manages acids and bases).
  • Being unable to swallow or take oral medication, which refers to medicine taken by mouth.
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Investigated drugs

  • Methenamine hippurate

    is the main treatment being tested in this study. It is a non-antibiotic medicine used to help prevent repeated urinary tract infections by making the urine less hospitable to bacteria.

  • Cephalexin

    is an antibiotic used in this study as a comparison to see how well it prevents urinary tract infections compared to the test treatment.

  • Septrin

    is a combination antibiotic used in this study to compare its effectiveness in preventing urinary tract infections against the test treatment.

  • Fosfomycin trometamol

    is an antibiotic used in this study to serve as a comparison for preventing recurrent urinary tract infections.

What is already known about the treatment

  • Cefalexin

    This medication is taken by mouth as a pill or liquid to treat various bacterial infections. It is a widely used antibiotic that belongs to the cephalosporin group. It works by preventing bacteria from building their protective cell walls, which eventually causes the bacteria to burst and die.

  • Sulfamethoxazole and Trimethoprim

    These two substances are taken orally in tablet form to treat different types of bacterial infections. They are classified as a combination antibiotic and are commonly used in medicine today. This medication works by blocking two different steps in the way bacteria produce folic acid, which is essential for their growth and survival.

  • Fosfomycin Trometamol

    This medication is administered orally to treat urinary tract infections. It is a well-established antibiotic used to fight various bacteria. On a molecular level, it works by interfering with the enzymes that bacteria use to build their cell walls, leading to the destruction of the bacteria.

  • Methenamine Hippurate

    This substance is taken by mouth to help prevent repeated urinary tract infections. Unlike traditional antibiotics, it is classified as an urinary antiseptic. Once it reaches the bladder, it turns into formaldehyde, which acts as a powerful agent to kill bacteria without the same risks of antibiotic resistance.

Investigated diseases

Recurrent urinary tract infections - This condition involves repeated infections of the urinary system, which includes the bladder and kidneys. It occurs when bacteria enter the urinary tract and cause inflammation. In many cases, these infections return multiple times over a period of months or years. The process typically begins with bacteria attaching to the lining of the urinary tract and multiplying. This can lead to symptoms such as discomfort or a frequent urge to urinate.
Trial detailsLast updated 7 Oct 2026
Age18+ yearsPhasePhase IIITrial ID2025-523922-42-00Protocol codeRUTI-METEstimated enrolment204 patientsSponsorConsorci Mar Parc De Salut De Barcelona

sourced from the EU Clinical Trials Register and site verification

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