Value of urinary prophylaxis with methenamine in gynecologic surgery

Acta Obstet Gynecol Scand. 2002 Aug;81(8):743-6. doi: 10.1080/j.1600-0412.2002.810810.x.


Background: There is a high risk of postoperative bacteriuria and urinary tract infection after gynecologic surgery. Postoperative asymptomatic bacteriuria often disappears without treatment, but 15-20% of patients still require treatment for postoperative urinary tract infection. This study was carried out to assess the value of prophylactic treatment with methenamine hippurate after routine gynecologic surgery.

Methods: This was a prospective, randomized, double-blind, placebo-controlled clinical trial comprising 145 patients undergoing routine gynecologic laparotomy or vaginal plastic surgery using a Foley catheter for 24 h. Antibiotics were not used. Subjects received 1 g Hiprex or placebo twice daily for 5 days. Urine was cultured preoperatively, at catheter removal, and 2 days later. Patients with positive cultures were not given antibiotics unless they were symptomatic. The follow-up period was 1 month.

Statistics: The chi-square test, Fisher exact test, and t-test were used with level of significance at 0.05, and odds ratios with 95% confidence intervals were calculated.

Results: Asymptomatic bacteriuria was diagnosed in 36 cases (50.0%) in the placebo group and 22 cases (30.1%) in the methenamine group (p = 0.02). Urinary tract infection was diagnosed in 10 cases (13.9%) in the placebo group and two cases (2.7%) in the methenamine group (p = 0.03). There were few adverse events.

Conclusions: Prophylactic treatment with methenamine hippurate significantly reduces the incidence of postoperative bacteriuria and urinary tract infection.

Publication types

  • Clinical Trial
  • Randomized Controlled Trial

MeSH terms

  • Administration, Oral
  • Adult
  • Aged
  • Aged, 80 and over
  • Anti-Infective Agents, Urinary / administration & dosage
  • Anti-Infective Agents, Urinary / therapeutic use*
  • Antibiotic Prophylaxis*
  • Bacteriuria / etiology
  • Bacteriuria / microbiology
  • Bacteriuria / prevention & control*
  • Double-Blind Method
  • Female
  • Gynecologic Surgical Procedures
  • Humans
  • Laparotomy
  • Methenamine / administration & dosage
  • Methenamine / therapeutic use*
  • Middle Aged
  • Postoperative Complications / etiology
  • Postoperative Complications / prevention & control*
  • Prospective Studies
  • Treatment Outcome
  • Urinary Catheterization / adverse effects*
  • Vagina / surgery


  • Anti-Infective Agents, Urinary
  • Methenamine