TY - JOUR T1 - Kidney function and the use of nitrofurantoin to treat urinary tract infections in older women JF - Canadian Medical Association Journal JO - CMAJ SP - 648 LP - 656 DO - 10.1503/cmaj.150067 VL - 187 IS - 9 AU - Namisha Singh AU - Sonja Gandhi AU - Eric McArthur AU - Louise Moist AU - Arsh K. Jain AU - Aiden R. Liu AU - Manish M. Sood AU - Amit X. Garg Y1 - 2015/06/16 UR - http://www.cmaj.ca/content/187/9/648.abstract N2 - Background: The antibiotic nitrofurantoin is commonly used to treat uncomplicated urinary tract infections. However, when this drug is used by patients with reduced kidney function, its urine concentration may be subtherapeutic.Methods: We conducted a population-based study of older women (mean age 79 years) in Ontario, Canada, whose estimated glomerular filtration rate was relatively low (median 38 mL/min per 1.73 m2) and for whom 1 of 4 antibiotics had been prescribed for urinary tract infection: nitrofurantoin, ciprofloxacin, norfloxacin or trimethoprim–sulfamethoxazole. We assessed 2 measures of treatment failure in the subsequent 14 days: receipt of a second antibiotic indicated for urinary tract infection and hospital encounter (emergency department visit or hospital admission) with a urinary tract infection. We repeated the analysis for older women with relatively high estimated glomerular filtration rate (median 69 mL/min per 1.73 m2).Results: The baseline characteristics of the 4 antibiotic groups were similar. Relative to nitrofurantoin, the other antibiotics (including ciprofloxacin) were associated with a lower rate of treatment failure among women with relatively low estimated glomerular filtration rate (for ciprofloxacin v. nitrofurantoin: second antibiotic prescription, 130/1989 [6.5%] v. 516/3739 [13.8%], odds ratio [OR] 0.44, 95% confidence interval [CI] 0.36–0.53; hospital encounter, 21/1989 [1.1%] v. 95/3739 [2.5%], OR 0.41, 95% CI 0.25–0.66). However, a similar risk of treatment failure with nitrofurantoin was also observed among women with relatively high estimated glomerular filtration rate. The results were consistent in multiple additional analyses.Interpretation: In this study, the presence of mild or moderate reductions in estimated glomerular filtration rate did not justify avoidance of nitrofurantoin. ER -