Background Recurrent urinary tract infections are common and current UK guidelines advocate prophylaxis with nitrofurantoin in selected patients¹. Nitrofurantoin-induced pulmonary toxicity (“Nitrofurantoin lung” or NL) is uncommon but can result in progressive respiratory failure. Locally we have observed a rise in NL. Pulmonary toxicity necessitates cessation of nitrofurantoin, however the utility of additional corticosteroid therapy remains controversial². We examined a detailed case series to ascertain the effect of drug cessation alone and addition of oral corticosteroids in NL.

Methods Using a local Interstitial Lung Disease database, we retrospectively identified patients who had presented with NL between 2009–2013. Patient demographics, imaging, pulmonary function and prescribing data were accessed. Local and national nitrofurantoin prescribing rates were also reviewed.

Results Scottish prescribing data demonstrated increased community nitrofurantoin prescriptions from 3.4 to 11 items/1000 patients from 2008–2012. Our database identified 13 NL cases (93% female, mean age 74 years, range 63–83). All had a history of chronic cystitis and presented with chronic NL. Cumulative lung function (available in 9 patients) demonstrated a mean improvement in% predicted FVC and FEV₁ of +33 (p = 0.009) and +37 (p = 0.006), respectively, following cessation of nitrofurantoin. 44% of patients were also prescribed oral prednisolone. Comparing these two groups (cessation + steroid vs cessation alone) showed no significant difference in mean% predicted FVC (p = 0.47) or FEV₁ (p = 0.87), gender, age or imaging at diagnosis. Following treatment, there was no significant difference in% predicted FVC (p = 0.87) or FEV₁ (p = 0.93) between groups. The mean% predicted FVC improvement was 31% in the steroid group and 34% in the cessation only group, showing no significant difference between groups (p = 0.86).

Conclusions With increased nitrofurantoin prescribing, the prevalence of NL will continue to rise throughout the UK and heightened awareness of the condition will be required in primary and secondary care. Our data demonstrates that significant improvements in lung function occur on cessation of nitrofurantoin and suggests no benefit is conferred by additional use of corticosteroid in patients with chronic NL.

References

1. Management of infection guidance for primary care (2012). http://www.hpa.org.uk/webc/HPAwebFile/HPAweb_C/1279888711402

2. Mendez et al. Chronic nitrofurantoin-induced lung disease. Mayo Clin Proc 2005;80(10):1298-302