Using Methenamine Hippurate to treat UTI

Methenamine Hippurate – An Answer to Urine Infections?

Methanamine Hippurate? Chances are you’ve never heard of it before. It is a treatment for preventing urine infections, and it’s been around for 60 years. Could it be useful for you? Many women suffer from urinary tract infections, and antibiotics are often used to treat urine infections, including the treatments available with The Doctor Service

Some women (and men) suffer with recurrent urinary tract infections, and the most common treatment for this is to take a regular antibiotic once daily. This helps to prevent urine infections, however there is a significantly higher risk of bacterial antibiotic resistance developing if this method is used, meaning the antibiotics may be less effective for these people in the future, so future infections of the body may not be effective to antibiotics. However bacteria do not appear to develop resistance to Methenamine Hippurate

How does it work?

Methanamine Hippurate does not act directly on the bacteria to kill or prevent growth of further bacteria. When taken it does not have any action on bacteria until it is passed through the kidneys, when it is converted into a substance called formaldehyde. From this moment it then becomes toxic to bacteria and kills bacteria within the urinary tract.

The benefit of this is that it does not become active until reaching the urinary tract, which means the rest of the body including healthy bacteria in the gut is not affected.

A meta-analysis of multiple review studies in 2016 actually found a reduced risk of side effects when taking methenamine hippurate compared to nitrofurantoin, a common antibiotic used for long term prevention of urine infections. This review also found multiple studies found no significant difference in outcomes of patients taking methenamine hippurate in comparison to nitrofurantoin.

A Cochrane systematic review in 2012 found that Methanamine hippurate may also be effective in preventing urinary tract infections provided there are no other underlying medical conditions such as kidney problems or a condition known as neuropathic bladder. They also found that adverse events (side effects) related to treatment were low too.

Why isn’t Methenamine widely used to treat Urine Infections?

It’s not clear why methenamine isn’t used as commonly as antibiotics such as nitrofurantoin and trimethoprim to help prevent urine infections, as it appears to be an effective alternative. It’s also shown to have lower side effects in studies when compared with antibiotics such as nitrofurantoin.

Although formaldehyde itself has been implicated in causing certain types of cancer at sustained high levels in the air, the levels of formaldehyde in methenamine hippurate are lower. We have found no studies to suggest an increased risk of cancer.

Further Information

If you experience recurrent urinary tract infections, then you may need to consider looking for the underlying causes, and also getting treatment to prevent further urine infections. Methenamine Hippurate is often a little known alternative to the use of other antibiotics to prevent urine infections. If you would like to know more about whether this medication may be useful for you, you should discuss this further with a suitably qualified health professional.

This article does not replace medical advice from a health professional, and should not be relied upon to guide treatment.

The Doctor Service offers further information on urine infections and cystitis as well as effective prescription medication in it’s section for the Treatment of Cystitis/Urine Infections.


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  2. British National Formulary
  3. Nitrofurantoin vs other prophylactic agents in reducing recurrent urinary tract infections in adult women: a systematic review and meta-analysis – Price, J, Guran L et al, AJOG Nov 2016
  4. Secondary prevention of recurrent urinary tract infections: comparison of the effect of placebo, methanamine hippurate, nitrofurantoin and trimethoprim alone, Kasanen et al, Second J Infect Disease 1982, Finland
  5. Prevention of recurrent urinary infection in women: a comparative trial between nitrofurantoin and methenamine hippurate. Brumfitt W et al, 1980, Roya; Free Hospital
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  10. MHRA
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  12. US Food & Drug Administration
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