An audit of nitrofurantoin use in three Australian hospitals

International guidelines have recommended the long-acting formulation of nitrofurantoin as first-line treatment for uncomplicated urinary tract infections (UTIs) since 2010. Australian guidelines have only recently listed nitrofurantoin as a first-line agent, but the long-acting formulation is not available. In the setting of increasing multidrug-resistance, the unavailability of the long-acting formulation of nitrofurantoin in Australia, and anecdotal perception of confusion regarding dosing, we audited nitrofurantoin use.

We performed a retrospective audit of nitrofurantoin use at Alfred Health. All patients dispensed nitrofurantoin from January 2016 to June 2018, as identified from pharmacy dispensing records, were eligible. We used a standardised case report form to extract data from medical records, including dosing regimen and indication.

We included 150 patients with 151 nitrofurantoin prescriptions in the analysis, of whom 74% [111/150] were female. Nitrofurantoin was most commonly dispensed for the treatment of UTIs (68% [103/151] versus 32% [48/151] for UTI prophylaxis). For the treatment of uncomplicated UTIs, the most frequently used dose was 100 mg twice daily for five days. In male patients, the 100 mg twice daily for seven days was the most popular regimen. The prophylactic dose of 50 mg once daily was used in women but rarely in men. We did not find evidence of dose adjustment for renal impairment.

While treatment duration was consistent with guidelines, the dosage and frequency used was often incorrect for the formulation and was not adjusted for renal function. Nitrofurantoin use is likely to increase, so clarification regarding optimal nitrofurantoin dosing regimens may be appropriate.