Methenamine Hippurate Versus Trimethoprim in the Prevention of Recurrent UTIs
Methenamine Hippurate Versus Trimethoprim in the Prevention of Recurrent UTIs
Several methods are available for use in the prevention of recurrent urinary tract infections
 (UTIs) over the past few decades. These methods include suppressive antibiotics, estrogen
 cream, methenamine hippurate, d-mannose, cranberry, probiotics, and vitamin C. Of these, the
 majority of the literature is in favor of use of suppressive antibiotics for preventing UTIs.
 However, this data is now about 10 years old. Increasing use of antibiotics over the years
 has lead to increased resistance of bacteria. In addition, long-term antibiotic use has
 several adverse effects, some life-threatening. There is recent literature evaluating the use
 of several of the alternatives to suppressive antibiotics with mixed results. A comparative
 study of the efficacy of methenamine hippurate to suppressive antibiotics is lacking in the
 current literature. Several early partly-randomized trials done with methenamine hippurate
 have shown promising results, but are only as recent as 1987. The primary objective of this
 prospective, randomized study is to determine whether there is a significant difference in
 the prevention of recurrent UTIs when given either methenamine hippurate or daily suppressive
 antibiotics. The secondary objective of this study is to determine how well patients are able
 to tolerate each of these medications and what adverse effects are observed in a given 1 year
 time period. The long-term goals of this study are to find an alternative to using
 suppressive antibiotics, potentially with a lower adverse effect profile and less of the
 dangers of long term antibiotic use. Finding an alternative to suppressive antibiotics would
 also tackle the issue of antibiotic resistance.
Hypothesis:

 The hypothesis of this study is that the group taking trimethoprim will have a lower
 recurrence rate than those taking methenamine hippurate based on the literature. The
 investigators aim to identify to what degree that difference is and whether or not it is an
 acceptable difference given the greater degree of an antibiotic resistance.

 Objectives:

 The primary objective of this prospective, randomized study is to determine whether there is
 a significant difference in the prevention of recurrent UTIs when given either methenamine
 hippurate or daily suppressive antibiotics independent of vaginal estrogen use.

 The secondary objective of this study is to determine how well patients are able to tolerate
 each of these medications and what adverse effects are observed in a 1 year time period.

 Specific Aims:

 1. Identify if there is a differential impact on prevention of recurrent UTIs when treated
 with either trimethoprim or methenamine hippurate in a 6 and 12 month period.

 2. Identify adverse reactions in each group.

 3. Determine whether or not estrogen has a more additive effect to trimethoprim or
 methenamine hippurate in post-menopausal women.

 4. Identify how well tolerated the study medications are and whether or not the size of the
 pills or the frequency of taking them prevents patients from continuing therapy.
Inclusion Criteria:

 -  recurrent UTI: at least 2 in the past 6 months or 3 in past year (culture positive)

 -  must have been symptomatic with dysuria, urgency, frequency, suprapubic pain,
 hematuria, malodorous urine

 -  treated for last UTI and negative urine culture on entry into study

 -  English speaking

 Exclusion Criteria:

 -  pregnancy

 -  urinary tract abnormalities (eg kidney stones)

 -  acute pyelonephritis

 -  renal insufficiency or failure

 -  known allergy to medications

 -  prophylaxis for post-coital recurrent UTIs