Urinary Tract InfectionsEarly Phase 1NCT06710899
Vitamin C and Hiprex in rUTI
A Early Phase 1 study testing Methenamine Hippurate 1g BD and Methenamine Hippurate 1g BD + Vitamin C 1g BD in people with Urinary Tract Infections, run by University Hospitals of North Midlands NHS Trust at 1 site in United Kingdom.
Trial summary
A single centre proof of concept study to assess whether Vitamin C improves the efficacy of Methenamine Hippurate (Hiprex®) in the prophylaxis of recurrent urinary tract infections (rUTIs) in women Read more about this study
- Who is it for?
- Ages 18 years and older, women only
- Conditions the study is for
- Urinary Tract Infections
- What is being tested?
- Methenamine Hippurate 1g BD and Methenamine Hippurate 1g BD + Vitamin C 1g BD
- Could I receive a placebo?
- No, everyone receives an active treatment
- How many people
- 20 participants
- Where
- 1 siteUnited Kingdom
- Study dates
- Jan 2027to Jan 2028
- Phase
- Early Phase 1
- Are there results?
- Not yet: the study is under way
Key requirements
Who can take part, as listed by the sponsor. Only the study team can confirm whether you are eligible, so take this list to your doctor.
- Ages 18 years and older
- Women only
- No healthy volunteers
- Adult, Older adult
Who may be able to join
- Female
- Age ≥18 years
- Recurrent proven UTI, defined as "two or more proven infections in six months or three or more infections in six months"
- Willing and able to give fully informed consent
- Patients suitable for prophylaxis following discussion with their clinician.
- No contra-indications to treatment with methenamine hippurate or Vitamin C
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- All women will have undergone standard diagnostic work-up and have followed routine conservative UTI prevention measures.
- A working email address to be used to submit urine pH results
- Willing and able to comply with the study procedures
- Females of childbearing potential must be willing to use a highly effective method of contraception (hormonal or barrier method of birth control; abstinence; sterilisation or vasectomised partner)
Who cannot join
- Males
- Women who are pregnant or breast-feeding
- Contraindications to methenamine hippurate as described in BNF: known allergy, gout, severe metabolic acidosis, severe dehydration, eGFR less than 10 ml/min, severe hepatic impairment
- Currently using vitamin C containing supplement or cranberry extract tablets
- Women using urinary alkalinisation agents, e.g potassium citrate, sodium bicarbonate
- Currently receiving any form of bladder instillation or intradetrusor Onabotulinum Toxin A injections
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- Patients already on low-dose antibiotics or methenamine hippurate (due to delay that will be incurred by 3-month washout period)
- Indwelling urinary catheter in situ or performing clean intermittent self-catheterisation
- Correctable urinary tract abnormalities, e.g., urinary tract calculi, urinary retention
- Formation of ileal conduit or augmented bladder
- Neurogenic bladder dysfunction
- Hyperoxaluria
Trial locations and contacts
1 site in 1 country. Contact the study team or a site near you to ask about taking part.
United Kingdom1 site
University Hospitals of North Midlands NHS Trust
Stoke-on-Trent, Staffordshire, ST4 6QG
About this study
Official title: Does Vitamin C Improve the Efficacy of Methenamine Hippurate (Hiprex®) in Prophylaxis of Recurrent Urinary Tract Infections? A Proof of Concept Study
A single centre proof of concept study to assess whether Vitamin C improves the efficacy of Methenamine Hippurate (Hiprex®) in the prophylaxis of recurrent urinary tract infections (rUTIs) in women
- Conditions
- Urinary Tract Infections
- Being tested
- Methenamine Hippurate 1g BD, Methenamine Hippurate 1g BD + Vitamin C 1g BD
- Medical subject headings
- Urinary Tract Infections
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
Methenamine Hippurate 1g BDDrug
Methenamine Hippurate 1g BD for 6 months
Methenamine Hippurate 1g BD + Vitamin C 1g BDDrug
Methenamine Hippurate 1g BD + Vitamin C 1g BD for 6 months
| Study group | Role | What they receive |
|---|---|---|
| Treatment phase A | Experimental | Methenamine Hippurate 1g BD for 6 months Receives: Drug: Methenamine Hippurate 1g BD |
| Treatment phase B | Experimental | Methenamine Hippurate 1g BD + Vitamin C 1g BD for 6 months Receives: Drug: Methenamine Hippurate 1g BD + Vitamin C 1g BD |
| Treatment phase C | Experimental | Methenamine 1g BD for 6 months Receives: Drug: Methenamine Hippurate 1g BD |
What is being measured
The primary outcome is the main question the study is designed to answer.
Frequency of UTIs
The incidence of symptomatic UTI during each six-month treatment phase of either methenamine hippurate alone or methenamine hippurate plus vitamin C
Measured: 24 months
Secondary outcomes (1)
Urine pH
Measurement of urine pH during each treatment phase
Measured: 24 months
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted29 Nov 2024
- Study startJan 2027 (estimated)
- Primary completionAug 2027 (estimated)
- Study completionJan 2028 (estimated)
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Other trials for Urinary Tract InfectionsStudies of the same condition, open and under way.
- What the trial phases meanHow a treatment moves from first tests in people to approval.
More details
For doctors and researchers: how the study is designed, who runs it, and its registry IDs.
Study design
- Study type
- Interventional
- Phase
- Early Phase 1
- Primary purpose
- Treatment
- Allocation
- Non-randomised
- Intervention model
- Sequential
- Masking
- None (open label)
- Enrolment
- 20 participants (estimated)
Sponsor and investigators
- Lead sponsor
- University Hospitals of North Midlands NHS Trust
- Sponsor type
- University, hospital or other
- Responsible party
- Sponsor
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT06710899
- Sponsor's protocol ID
- 3399
- Status last verified
- Feb 2026
- First submitted
- 26 Nov 2024
- Last updated
- 11 Feb 2026
- Results posted
- No
- FDA-regulated drug
- No
- FDA-regulated device
- No
Study at a glance
From the registry record, last updated by the sponsor on 11 Feb 2026. Recruitment status is as the sponsor reported it: confirm with the study team.
- Official title
- Does Vitamin C Improve the Efficacy of Methenamine Hippurate (Hiprex®) in Prophylaxis of Recurrent Urinary Tract Infections? A Proof of Concept Study
- ClinicalTrials.gov ID
- NCT06710899
- Acronym / sponsor ID
- 3399
- Conditions
- Urinary Tract Infections
- Phase
- Early Phase 1
- Study type
- Interventional
- Recruitment status
- Not yet recruiting
- Enrolment
- 20 participants (estimated)
- Lead sponsor
- University Hospitals of North Midlands NHS TrustUniversity, hospital or other
- Study start
- Jan 2027 (estimated)
- Primary completion
- Aug 2027 (estimated)
- Study completion
- Jan 2028 (estimated)
- First posted
- 29 Nov 2024 (actual)
- Results
- Not posted in the source record
Clinical summary
The research question as the sponsor registered it. This describes what the study plans to test, not what it found.
A single centre proof of concept study to assess whether Vitamin C improves the efficacy of Methenamine Hippurate (Hiprex®) in the prophylaxis of recurrent urinary tract infections (rUTIs) in women
Study design
- Primary purpose
- Treatment
- Allocation
- Non-randomised
- Intervention model
- Sequential
- Masking
- None (open label)
- Number of arms
- 3
| Arm | Type | Receives |
|---|---|---|
| Treatment phase A | Experimental | Drug: Methenamine Hippurate 1g BDMethenamine Hippurate 1g BD for 6 months |
| Treatment phase B | Experimental | Drug: Methenamine Hippurate 1g BD + Vitamin C 1g BDMethenamine Hippurate 1g BD + Vitamin C 1g BD for 6 months |
| Treatment phase C | Experimental | Drug: Methenamine Hippurate 1g BDMethenamine 1g BD for 6 months |
Who may qualify
- Ages
- 18 years and older
- Sex
- Female only
- Healthy volunteers
- Not accepted
- Age groups
- Adult, Older adult
Key inclusion criteria (10 listed)
- Female
- Age ≥18 years
- Recurrent proven UTI, defined as "two or more proven infections in six months or three or more infections in six months"
- Willing and able to give fully informed consent
- Patients suitable for prophylaxis following discussion with their clinician.
Key exclusion criteria (12 listed)
- Males
- Women who are pregnant or breast-feeding
- Contraindications to methenamine hippurate as described in BNF: known allergy, gout, severe metabolic acidosis, severe dehydration, eGFR less than 10 ml/min, severe hepatic impairment
- Currently using vitamin C containing supplement or cranberry extract tablets
- Women using urinary alkalinisation agents, e.g potassium citrate, sodium bicarbonate
Eligibility is decided by the study team after screening; this overview does not establish that a patient qualifies. Full inclusion and exclusion criteria.
Interventions
| Intervention | Type | Arms |
|---|---|---|
| Methenamine Hippurate 1g BDMethenamine Hippurate 1g BD for 6 months | Drug | Treatment phase A, Treatment phase C |
| Methenamine Hippurate 1g BD + Vitamin C 1g BDMethenamine Hippurate 1g BD + Vitamin C 1g BD for 6 months | Drug | Treatment phase B |
Primary outcome
Frequency of UTIs
Time frame: 24 months
The incidence of symptomatic UTI during each six-month treatment phase of either methenamine hippurate alone or methenamine hippurate plus vitamin C
1 secondary outcome
Urine pH
Time frame: 24 months
Results and safety
This study is still under way. Results are not available in the source record yet.
Research links
- Official record on ClinicalTrials.govLast updated by the sponsor 11 Feb 2026.
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Referral and contact
AzTrials does not enrol participants or take referrals. Contact the study team or a site listed below; they decide who can take part.
1 site in 1 country: see every site and its status.
Questions about this trial
What is this clinical trial studying?
A Early Phase 1 study testing Methenamine Hippurate 1g BD and Methenamine Hippurate 1g BD + Vitamin C 1g BD in people with Urinary Tract Infections, run by University Hospitals of North Midlands NHS Trust at 1 site in United Kingdom.
The full registered description is in the About this study section and the official record.
Who may be eligible to take part?
The sponsor lists 10 inclusion and 12 exclusion criteria. Eligibility is decided by the study team after screening, so read the full criteria and contact a listed site.
Is this clinical trial currently recruiting?
The record says: opening soon, as of the sponsor's last update on 11 Feb 2026. Status can change between updates, so confirm with the study contact before making plans.
Where is the study taking place?
The record lists 1 site in United Kingdom. Whether a site is taking part right now should be confirmed with that site. See every site.
What are the possible benefits and risks?
They depend on the study and the treatment, and no study can promise a benefit. The study team explains the known risks during informed consent, before anyone joins; the record itself does not list them.
What does this phase mean?
Early Phase 1 (sometimes called Phase 0) studies give a very small amount of a treatment to a few people, mainly to see how the body handles it.
Not every study follows the same path, and some studies (observational studies, device studies) have no phase.
Are results available for this study?
This study is still under way. Results are not available in the source record yet.
How can a doctor refer a patient or contact the research team?
Contact Aviva Ogbolosingha (01782 675380, aviva.ogbolosingha@uhnm.nhs.uk), or a site near the patient. AzTrials does not enrol participants or take referrals.
What does the primary outcome measure?
Frequency of UTIs (time frame: 24 months). It is what the study was designed to measure, not a finding.
Where can I read the original study information?
Does a listing mean the treatment is approved or proven to work?
No. A listing means the study is registered. It does not show that the treatment is safe, works, or is approved by a regulator.
How often is this information updated?
AzTrials copies changed records from ClinicalTrials.gov every night and reloads the whole registry every week. The sponsor last updated this record on 11 Feb 2026.