Methenamine hippurate for preventing urinary tract infections

Area of Science:

• Urology
• Infectious Diseases
• Pharmacology

Background:

• Methenamine salts are utilized as an alternative to antibiotics for preventing urinary tract infections (UTIs).
• This systematic review was initially published in 2002 and updated in 2007.

Purpose of the Study:

• To evaluate the efficacy and safety of methenamine hippurate in preventing UTIs.
• To assess the benefits and harms associated with methenamine hippurate for UTI prophylaxis.

Main Methods:

• Conducted a systematic review of randomized controlled trials (RCTs) and quasi-RCTs assessing methenamine hippurate for UTI prevention.
• Searched multiple databases (CENTRAL, MEDLINE, EMBASE) and contacted manufacturers for studies up to June 2012.
• Two independent reviewers assessed study quality and extracted data, using random-effects models for analysis.

Main Results:

• Included 13 studies with 2032 participants; study quality was mixed.
• Methenamine hippurate showed potential benefit in patients without renal abnormalities (symptomatic UTI: RR 0.24; bacteriuria: RR 0.56).
• No significant benefit was observed in patients with renal abnormalities (symptomatic UTI: RR 1.54; bacteriuria: RR 1.29). Short-term use (≤1 week) significantly reduced symptomatic UTIs in those without renal issues.

Conclusions:

• Methenamine hippurate may be effective for UTI prevention in patients without renal tract abnormalities, particularly for short-term prophylaxis.
• It appears ineffective in patients with neuropathic bladder or existing renal abnormalities.
• Further high-quality RCTs are needed to confirm efficacy, especially for long-term use in patients without neuropathic bladder. Adverse events were low but poorly described.