Sulfa antibiotics, such as a combination product of trimethoprim and sulfamethoxazole, have traditionally been the drugs of choice for urinary tract infections (UTIs) and remained the most common treatment as recently as a decade ago. However, increasing sulfa resistance among Escherichia coli may have led to changes in prescribing practices.
We used the 2000-2002 National Ambulatory Medical Care Survey and National Hospital Ambulatory Medical Care Survey to obtain nationally representative data on antibiotics prescribed for women with isolated outpatient UTIs following visits to physicians' offices, hospital clinics, and emergency departments (n = 2638). Logistic regression was used to determine predictors of quinolone use.
Quinolones were more commonly prescribed than sulfa antibiotics in each year evaluated. In the most recent year of data, quinolones were prescribed in 48% and sulfas in 33% of UTI visits (P<.04). Quinolones were significantly more likely to be prescribed to older patients and in visits occurring in the Northeast; however, no difference in quinolone prescribing was seen when evaluating insurance status, setting, race, ethnicity, health care provider type, and year. Approximately one third of the quinolones used were broader-spectrum agents.
Quinolones have surpassed sulfas as the most common class of antibiotic prescribed for isolated outpatient UTI in women. Few significant predictors of quinolone use exist, suggesting that the increase is not confined to a certain subset of patients. This pervasive growth in quinolone use raises concerns about increases in resistance to this important class of antibiotics.