An acute uncomplicated urinary tract infection (UTI) in women can be treated effectively with a one- to three-day course of antibiotics. However, the effectiveness of various regimens has not been well-studied. McCarty and colleagues compared the safety and efficacy of a three-day course of ciprofloxacin, ofloxacin and trimethoprim/sulfamethoxazole (TMP/SMX; Bactrim, Septra) in the treatment of acute UTI in women.

Women with a diagnosis of acute uncomplicated UTI were eligible for the multicenter trial if they had a urine culture with at least 10³ colony-forming units (CFU) per mL of urine, pyuria, dysuria and urinary frequency. Exclusion criteria included bacteriuria, urinary tract obstruction, neurogenic bladder or multiple causative organisms. Those who met the inclusion criteria were randomized to receive a three-day course of either 100 mg of ciprofloxacin twice daily, 200 mg of ofloxacin twice daily or 160/800 mg of TMP/SMX twice daily. Patients were evaluated at baseline, on day three, between days three and 10, and four to six weeks after the study was completed. Two thirds of the women had no previous history of UTI and had had symptoms for at least two days. Serial urine cultures were obtained to determine effectiveness, and adverse events were recorded. Clinical responses were defined as resolution of symptoms, failure, indeterminate or recurrence.

A total of 688 women were enrolled in the study. Of these, 229 received ciprofloxacin, 231 received ofloxacin and 228 received TMP/SMX. Escherichia coli was identified as the most common pathogen, affecting 81 percent of patients. Overall, the bacteriologic and clinical response rates were similar in all groups. All isolates of E. coli responded to ciprofloxacin and ofloxacin, and only 6 percent were resistant to TMP/SMX. Bacteria were eradicated in 94 percent of patients in the ciprofloxacin group, 97 percent in the ofloxacin group and 92 percent in the TMP/SMX group. Symptoms resolved in more than 90 percent of patients in all groups by the end of the treatment period. Recurrence occurred after four to six weeks in only 61 patients, with most instances of recurrence caused by E. coli and affecting patients in the TMP/SMX group. Adverse events, including gastrointestinal disturbances, rash and fever, occurred more commonly in the ofloxacin (34 percent) and TMP/SMX (35 percent) groups than in the ciprofloxacin group (26 percent).

The authors conclude that each of the antibiotic regimens tested was effective in treating acute uncomplicated UTI in women. Ciprofloxacin and ofloxacin are more expensive than TMP/SMX, but their side effect profiles are better. Because of increasing prevalence of TMP/SMX–resistant E. coli, the use of fluoroquinolones, especially in areas where this resistance is common, may be indicated.