Antiseptic, A group of UK researchers led by physicians and scientists from Newcastle-upon-Tyne set out to see if methenamine hippurate could help women avoid recurrent UTIs (urinary tract infections). The findings of the study were published in the British Medical Journal (‘The BMJ’). Current recommendations recommend daily low-dose antibiotics as the standard preventive (prophylactic) treatment for recurring urinary tract infection (UTI).
Long-term antibiotic use, on the other hand, has been linked to antibiotic resistance, necessitating urgent research into non-antibiotic alternatives. Methenamine hippurate is bactericidal that sterilizes urine and inhibits microorganism growth. Previous research has shown that it can help prevent UTIs, but the evidence is still equivocal, and more randomized trials are needed.
The non-inferiority margin, determined through a series of patient focus group meetings, was one UTI episode per year. During the 12-month treatment period, the UTI rate in the antibiotic group was 0.89 episodes per person-year and 1.38 in the methenamine group – an absolute difference of 0.49 episodes per person-year.
This minor difference between the two groups was less than the predefined threshold of one UTI episode per year, implying that methenamine was no worse than antibiotics at preventing urinary tract infection. Methenamine was also linked to lower antibiotic consumption, as well as comparable levels of adverse reactions and treatment satisfaction when compared to daily antibiotics.
The new findings are based on 240 women (aged 18 and up) who have recurring urinary tract infections that require prophylactic treatment. Prior to trial entry, these women had more than six UTI episodes per year on average. Between June 2016 and June 2018, women were recruited from UK secondary care centers and randomly assigned to daily antibiotics (102 women) or daily methenamine hippurate (103 women) for 12 months, with three monthly assessments up to 18 months.
And the results remained consistent after additional analyses, such as excluding days spent on antibiotics for a urinary tract infection, lending credence to the findings. The researchers acknowledge that data on the long-term safety of methenamine hippurate are limited, and they acknowledge some trial limitations, such as a lack of blinding and differences in antibiotics prescribed, that may have influenced their findings.
They also note that four participants assigned to methenamine hippurate were hospitalized due to UTI, and six participants assigned to methenamine hippurate reported fever during a UTI episode (febrile UTI). They do say, however, that this was a well-designed trial that accurately represented the wide range of women with recurrent UTI seen in routine NHS practice.
As a result, the researchers stated that their findings “could support a change in practice in terms of preventive treatments for recurrent UTI and provide patients and clinicians with a credible alternative to daily antibiotics, giving them the confidence to pursue strategies that avoid long term antibiotic use.”