Quinolone is more effective than amoxicillin-clavulanate for uncomplicated UTI

The fluoroquinolone ciprofloxacin (Cipro) appears to be more effective than amoxicillin-clavulanate (Augmentin) as a treatment for acute uncomplicated urinary tract infections in women, even in those infected with susceptible strains, according to a study published in last week's JAMA (2005; 293:949-55).

Researchers from the University of Washington, Seattle, conducted a randomized, single-blind trial of 370 women (aged 18-45 years) with symptoms of acute uncomplicated cystitis and a urine culture with at least 100 colony-forming units of uropathogens per milliliter. Women either received amoxicillin-clavulanate, 500 mg/125 mg, twice daily or ciprofloxacin, 250 mg twice daily, for 3 days. Patients were followed for 4 months.

More than half (58%) of the women treated with amoxicillin-clavulanate achieved a clinical cure, compared with 77% of women treated with ciprofloxacin. Investigators also found that amoxicillin-clavulanate was not as effective as ciprofloxacin in women infected with strains susceptible to amoxicillin-clavulanate.

"This difference may be due to the inferior ability of amoxicillin-clavulanate to eradicate vaginal E coli, facilitating early reinfection," wrote the authors, led by Thomas M. Hooton, MD.