Introduction

Antibiotic prophylaxis has been the mainstay of management of recurrent urinary tract infections (rUTIs). However, it is associated with concerns regarding antimicrobial resistance and substantial adverse events due to prolonged exposure to antibiotics. Methenamine hippurate (MH), seems to be a promising non-antibiotic option for prevention of rUTIs. A majority of the studies have evaluated the efficacy of MH in uncomplicated rUTIs. There is lack of data on its efficacy in patients with structural urinary tract abnormalities, functional disorders or in those requiring catheterization.

Aim

To assess the efficacy of MH in the prophylaxis of rUTIs across diverse patient populations, with a specific focus on patients with structural or functional abnormalities of the urinary tract and those requiring catheterization.

Method

Study Design

•  Retrospective observational study

  Patient Profile

• Patients with rUTIs defined as occurrence of >2 symptomatic episodes within 6 months or >3 episodes within a year
• Diagnosis was confirmed with positive urine cultures and presence of clinical symptoms of UTIs

Treatment Strategy

• The cohort comprised of 150 patients prescribed MH 1 g twice daily for 3 months
• Patients who were willing to continue, were offered treatment for another 3 months
• Demographics, radiological findings, functional urological status, cystoscopy findings, catheter use, and treatment outcomes were assessed

Endpoints

Primary Endpoints

• Resolution of symptoms
  • Complete resolution defined as no positive cultures and absence of symptoms
  • Partial improvement defined as reduction in the frequency and/or severity of culture-confirmed infections vs baseline
  • No improvement defined as no change in the frequency and severity of UTIs

  Secondary Endpoints

• Treatment tolerability
• Adverse events (AEs)
• Treatment discontinuation

Safety Endpoints

• Patient-reported side effects
• Treatment cessation

Results

• The baseline characteristics of the cohort
  • 88% females (n=132) and 12% males (n=18)
  • Median age 60 years
  • Radiological assessment of urinary tract was normal in 80.7%
  • Normal functional urological status in 68.7%
  • Normal cystoscopy findings in 59/76 patients
  • 18.7% used catheters to empty the bladder, 14.7% performed intermittent self-catheterization, 2.7% had subrapubic catheters and 1.3% had indwelling urethral catheters
• After 12 weeks of treatment, 66.7% of patients showed clinical improvement
• At the end of 6 months, clinical improvement was sustained in 30.7%, while 23.3% reported reduced frequency or severity
• Among the evaluable patients, the overall odds of sustained or partial improvement were high (54%), with patients more than twice as likely to experience benefit than showing no improvement; OR 2.25
• More men were likely to improve as compared to women; 83.3% vs 64.4%; OR 2.83, though the subgroup size was small
• There was no significant difference in long-term outcomes based on radiological findings, functional urological status and catheter use
• No side effects were reported by 71.3%
• Nausea was the most commonly reported side effect
• MH was generally well tolerated

Conclusion

• Methenamine hippurate was effective and well tolerated across diverse patient populations regardless of structural or functional urinary tract abnormalities and catheter use.
• Methenamine hippurate can be a promising non-antibiotic alternative to long-term antibiotic prophylaxis.

Cureus. 2025 Dec 5;17(12):e98511. Doi: 10.7759/cureus.98511.