Abstract / Summary
Background: Methenamine hippurate (MH) is a nonantibiotic urinary antiseptic with proven efficacy for preventing recurrent urinary tract infections (rUTIs). Given concerns about antimicrobial resistance, its perioperative use in endourological procedures could potentially reduce antibiotic exposure. Objectives: To review the evidence on MH for infection prophylaxis in invasive urological diagnostics and endourological interventions. Methods: Data source: Embase, MEDLINE, and Web of Science were searched from inception to 28 April 2026 without language restrictions, by backward and forward citation searching. Study eligibility criteria: Randomized and nonrandomized studies. Participants: Adults undergoing invasive urological diagnostics and endourological procedures. Interventions: MH at any dose and any timing including combined strategies were compared with any antimicrobials prophylaxis, placebo or no treatment. The primary outcome was postoperative symptomatic urinary tract infection (UTI); bacteriuria and infectious complications were secondary outcomes. Assessment of risk of bias: Risk of bias was assessed by two independent reviewers using the RoB 2. Methods of data synthesis: Two reviewers performed selection and extraction independently. Findings were synthesized in a narrative fashion; a meta-analysis was not appropriate. Results: Among 173 screened records, two dated randomized trials met the inclusion criteria, both in transurethral prostate surgery; none addressed cystoscopy, urodynamic investigations, intradetrusor botulinum toxin A injections, or ureteroscopy. In 42 men undergoing transurethral resection of the prostate, patients receiving perioperative cefotaxime had significantly lower postoperative bacteriuria than MH recipients (2 of 22 vs. 15/20; p <0.05), although septicaemia did not differ (0 of 22 vs. 2 of 20); however, the trial was too small for conclusions. In a double-blind trial of 86 men, MH showed no advantage over a comparator for bacteriuria or antibiotic requirements. Overall, the evidence is limited by small samples, heterogeneous designs, and study age. Conclusions: Despite strong evidence for MH in rUTI prevention, data on its use in endourological procedures are extremely limited. Although its nonantibiotic mechanism and favourable resistance profile may make it a promising prophylactic candidate, current evidence is missing completely. Well-designed prospective trials with clinically defined UTI endpoints are needed to define its role.