27 March 2019

An oldie but a goodie: The heritage treatment that’s not an antibiotic



Australia has very high rates of antibiotic use compared with other countries – but when it comes to preventing recurrent urinary tract infections (UTIs), antibiotics don’t have to be the only answer, research suggests.1,2

Nearly 45% of Australians had at least one antibiotic script filled on the PBS or RPBS in 2015, according to a report by the Australian Commission on Safety and Quality in Health Care.2 

The Antimicrobial Use and Resistance in Australia 2017 (AURA 2017) report showed that UTIs were among the highest conditions that prompted antibiotic prescribing in hospitals.2

As a result, UTIs were also among the top conditions responsible for inappropriate prescribing of some antibiotics, such as cephalexin.2

Yet prophylactic cephalexin or trimethoprim are among the recommended measures to help prevent recurrent UTIs, defined as at least two infections in six months or at least three infections in one year.4–7

So, faced with patients with recurrent UTIs, how can GPs avoid antibiotic over-prescribing? Especially since “antibiotics have been prescribed so extensively that resistant bacteria have made prophylaxis and treatment of UTI a more difficult task”.8

Well-established treatment

Instead of looking forward to the development of new super-antibiotics, the answer could be to look back and start re-using well-established treatments, research suggests.1

Hiprex (hexamine hippurate, also known as methenamine hippurate) has been proven to be an effective prophylactic agent against recurrent UTIs, with few side effects.9,10

And its efficacy is long-established. In the 1980s, a small Swedish crossover trial demonstrated that 1g given twice-daily for two years reduced recurrent symptomatic infections by 73% compared with placebo.10 

Adverse effects, which are usually mild, include nausea, upset stomach, painful urination, rash and inflammation of the mouth.11

Its mechanism of action means it has the advantage of not inducing cross-resistance to conventional antibiotics.1,10  In acidic urine, hexamine (methenamine) is hydrolysed to formaldehyde, which has antibacterial activity, but is not an antibiotic.1

“This forgotten antiseptic will become more important as bacteria continue to become resistant to antibiotics,” researchers suggest.1

Hiprex is available in packs of 20 or 100 tablets.11 The pack of 100 tablets is listed on the PBS.12 Dosage is 1g twice daily for adults, or 500mg to 1g twice-daily for children aged 6–12 years.11


  1. Lo TS et al. Expert Rev Anti Infect Ther 2014; 12(5): 549–54.
  2. Australian Commission on Safety and Quality in Health Care. AURA 2017. Second Australian report on antimicrobial use and resistance in human health.
  3. Australian Commission on Safety and Quality in Health Care. AURA 2016. First Australian report on antimicrobial use and resistance in human health.
  4. Geerlings SE et al. Infect Dis Clin North Am 2014; 28(1): 135–47.
  5. Arnold JJ et al. Am Fam Physician 2016;93(7):560–69. Available online: https://www.aafp.org/afp/2016/0401/p560.html Accessed 26/9/18.
  6. Hooton TM and Gupta K. Recurrent urinary tract infections in women. UpToDate, 21 November 2016.

Available online: https://www.uptodate.com/contents/recurrent-urinary-tract-infection-in-women#H243572567 Accessed 26/9/18.

  1. Scottish Medicines Consortium, Scottish Antimicrobial Prescribing Group. Guidance on Management of Recurrent Urinary Tract Infection in Non-pregnant Women, June 2016. Available online:

https://www.scottishmedicines.org.uk/files/sapg1/Management_of_recurrent_lower_UTI_in_non-pregnant_women.pdf Accessed 26/9/18.

  1. Smelov V et al. Eur Urol 2016; Suppl 15: 71–80.
  2. Lee BSB, Bhuta T, Simpson JM, Craig JC. Methenamine hippurate for preventing urinary tract infections. Cochrane Database of Systematic Reviews2012, Issue 10. Art. No.: CD003265. DOI: 10.1002/14651858.CD003265.pub3.
  3. Cronberg S et al. BMJ 1987; 294: 1507–08.
  4. Hiprex Consumer Medicine Information, November 2017.
  5. Pharmaceutical Benefits Schedule, September 2018.

PBS Information: This product is listed on the PBS as a drug for the suppression or elimination of bacteriuria associated with chronic or recurrent infection of the urinary tract, especially when long-term therapy is indicated.

© 2018 iNova Pharmaceuticals (Australia) Pty Limited. ABN 13 617 871 539. Level 10, 12 Help Street Chatswood NSW 2067, Australia. p. 1800 630 056. www.inovapharma.com.

AU-2018-10-0015 Date of preparation: October 2018.