The Effect of Methenamine Hippurate to Reduce Antibiotic Prescribing in Elderly Women With Recurrent UTI

Recurrent urinary tract infection (UTI) in elderly women is a major driver of antibiotic prescription. Hence, the question of feasible and appropriate preventive measures are important issues in this field. Methenamine hippurate is frequently prescribed in Norway and Sweden as prophylaxis for recurrent UTI. Methenamine hippurate acts via the production of formaldehyde from hexamine, which in turn acts as a bacteriostatic agent, therefore methenamine hippurate is not defined as an antibiotic. According to a Cochrane review 2012 the rates of adverse events for preventing UTI was low. Although this review showed methenamine hippurate might be effective in preventing UTI in the short term, there is a need for large well-conducted randomised controlled trial (RCT) to clarify both the safety and effectivity of preventive methenamine hippurate for longer term use. This is particularly important for longer term use for people without neuropathic bladder disorders. A Norwegian longitudinal observational study including women aged 50-80 years with recurrent UTI indicated a significant and large reduction of more than 50% in antibiotic prescriptions for UTI after start of prophylactic methenamine hippurate. This further strengthens the need for an RCT of methenamine hippurate as prophylaxis for recurrent UTI.