Antiseptic drug as good as low-dose antibiotics for recurrent UTI prevention

Antiseptic drug methenamine hippurate is as good as antibiotics for preventing recurrent urinary tract infections (UTIs) in women, a study has found.

The drug may be an alternative for those who are worried about antibiotic resistance, the researchers concluded.

The year-long study of more than 200 participants, published in the BMJ, found that low-dose antibiotics were slightly better at preventing UTIs than methenamine hippurate but the difference equated to less than one UTI per year.

Adverse reactions – which were generally mild – were also equivalent among the two groups. Given the risk of antibiotic resistance, the results provide more evidence for methenamine hippurate as a treatment option in this group, the researchers said.

Those taking part in the study had self-reported having six to seven UTIs on average in the 12 months before taking part. Between a fifth and a quarter of them had received antibiotic prophylaxis therapy before.

The analysis after a year of treatment showed an incidence of antibiotic-treated UTIs of 0.89 episodes per person per year in the antibiotics group and 1.38 in the methenamine hippurate group, but with an absolute difference of 0.49, which the researchers noted was not clinically relevant.

Almost half (43%) of women in the methenamine hippurate group were completely free of UTIs in the 12-month treatment period as were 54% of the antibiotic group, who had received either nitrofurantoin, trimethoprime or cefalaxin.

The researchers also found that during the six-month follow-up period after treatment ended, UTI rates increased but remained substantially lower than they had before the study began.

Swabs taken during the 12-month treatment period also showed that a higher proportion of patients allocated to daily prophylactic antibiotics showed E Coli resistance to at least one antibiotic.

But the researchers also reported that four participants taking methenamine hippurate were admitted to hospital because of a UTI, and six participants in that group reported a fever during a UTI episode.

Study leader Mr Chris Harding, consultant urological surgeon at the Freeman Hospital in Newcastle, said the results could support GPs to have evidence-based discussions around preventive treatments for recurrent UTIs and provide patients and clinicians with a credible alternative to daily long-term antibiotics as part of shared decision making.

He said: ‘Antibiotics were a little bit better at preventing UTI but it wasn’t clinically relevant. When you look at the NICE guidance, it says there’s not enough evidence to recommend methenamine hippurate but now we have provided that evidence.’

He added that there was variation around the country as to the use of methenamine hippurate, which had been around for some time but had been forgotten by some.

‘The potential advantage is you don’t build up antibiotic resistance and this will give GPs the confidence to use this treatment,’ he said.

In 2019, researchers called for faster, more accurate tests for diagnosing UTIs to prevent the overprescribing of antibiotics.

It comes as a recent study showed that GPs practising under pressure are more likely to prescribe broad-spectrum antibiotics.