What is the use of Methenamine (Hiprex)?

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Last updated: February 21, 2025View editorial policy

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From the Guidelines

Methenamine hippurate, also known as Hiprex, is recommended for the prevention of urinary tract infections (UTIs) in patients with intact bladder anatomy, at a dose of 1 g twice daily, as an alternative to prophylactic antibiotics. To use Methenamine hippurate effectively:

  • Take it with plenty of water.
  • For best results, maintain a slightly acidic urine pH (below 6.0).
  • Continue taking it as prescribed, even if symptoms improve.
  • It's often used as a long-term preventive measure for recurrent UTIs. Methenamine hippurate works by releasing formaldehyde in the urine, which kills bacteria, as stated in the guidelines for the prevention, diagnosis, and management of urinary tract infections in pediatrics and adults: a wikiguidelines group consensus statement 1. The use of Methenamine hippurate is supported by a systematic review, which included a multicenter, open-label, randomized noninferiority trial, and found that Methenamine hippurate was noninferior to antibiotics for the prevention of UTIs 1. Common side effects can include stomach upset, nausea, and rash. It's essential to inform your doctor of any other medications you're taking, as Methenamine hippurate can interact with certain drugs. While Methenamine hippurate is generally effective for preventing UTIs, it may not be suitable for treating active infections. In those cases, other antibiotics might be prescribed. Always consult with a healthcare provider for personalized advice and treatment. Key considerations for the use of Methenamine hippurate include:
  • Patient selection: Methenamine hippurate is recommended for patients with intact bladder anatomy.
  • Dosing: The typical recommended dose for adults is 1 g twice daily.
  • Monitoring: Patients should be monitored for side effects and interactions with other medications.
  • Alternative treatments: Other antibiotics may be prescribed for active infections or in cases where Methenamine hippurate is not effective.

From the FDA Drug Label

Methenamine hippurate tablets is indicated for prophylactic or suppressive treatment of frequently recurring urinary tract infections when long-term therapy is considered necessary. The use of Methenamine (Hiprex) is for the prophylactic or suppressive treatment of frequently recurring urinary tract infections [ 2 ].

  • The drug should only be used after eradication of the infection by other appropriate antimicrobial agents.
  • It is used to prevent infections that are proven or strongly suspected to be caused by susceptible bacteria [ 2 ].

From the Research

Use of Methenamine (Hiprex)

Methenamine hippurate, also known as Hiprex, is a urinary antiseptic used for the prevention of recurrent urinary tract infections (UTIs) [ 3 ]. The evidence suggests that methenamine hippurate may be effective in reducing the incidence of UTIs in certain populations, including older women [ 3 ] and adult renal transplant recipients [ 4 ].

Key Findings

  • Methenamine hippurate may reduce the incidence of UTIs in older women with recurrent UTIs [ 3 ].
  • The use of methenamine hippurate may decrease the frequency of UTIs, antibiotic therapy, and hospitalization due to UTIs in adult renal transplant recipients [ 4 ].
  • Methenamine hippurate may be effective in preventing UTIs in patients without renal tract abnormalities, particularly when used for short-term prophylaxis [ 5, 6 ].
  • The rate of adverse events associated with methenamine hippurate is generally low [ 5, 4, 6 ].

Population-Specific Effects

  • Older women: Methenamine hippurate may reduce the incidence of UTIs in older women with recurrent UTIs [ 3 ].
  • Adult renal transplant recipients: Methenamine hippurate may decrease the frequency of UTIs, antibiotic therapy, and hospitalization due to UTIs [ 4 ].
  • Patients without renal tract abnormalities: Methenamine hippurate may be effective in preventing UTIs, particularly when used for short-term prophylaxis [ 5, 6 ].

Professional Medical Disclaimer

This information is intended for healthcare professionals. Any medical decision-making should rely on clinical judgment and independently verified information. The content provided herein does not replace professional discretion and should be considered supplementary to established clinical guidelines. Healthcare providers should verify all information against primary literature and current practice standards before application in patient care. Dr.Oracle assumes no liability for clinical decisions based on this content.

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