Antibiotic more effective than cranberry capsules at preventing UTIs

August 11, 2011

In premenopausal women who have repeated urinary tract infections, the antibiotic trimethoprim-sulfamethoxazole (TMP-SMX [Bactrim, Septra DS]) appears to be more effective than cranberry capsules for preventing recurrent infections, at the risk of contributing to antibiotic resistance, Dutch researchers recently reported.

In premenopausal women who have repeated urinary tract infections, the antibiotic trimethoprim-sulfamethoxazole (TMP-SMX [Bactrim, Septra DS]) appears to be more effective than cranberry capsules for preventing recurrent infections, at the risk of contributing to antibiotic resistance, Dutch researchers recently reported.

First author Mariëlle A.J. Beerepoot, MD, of the Academic Medical Center, Amsterdam, the Netherlands, and colleagues conducted a double-blind noninferiority trial of cranberry capsules and TMP-SMX. The 221 premenopausal women in the study had reported at least three symptomatic UTIs in the previous year. They were randomized to take either TMP-SMX (480 mg at night, plus one placebo capsule twice daily) or cranberry capsules (500 mg twice daily, plus one placebo tablet at night) for 12 months.

Researchers assessed participants’ clinical status once per month (and for 3 months after stopping the study medication) via urine and feces samples and a questionnaire.

At 12 months, the average number of clinical recurrences was 1.8 in the TMP-SMX group and 4.0 in the cranberry capsules group. Recurrence occurred, on average, after 8 months in the drug group and after 4 months in the cranberry capsules group. Antibiotic resistance rates tripled in the pathogens found in patients in the TMP-SMX group, although 3 months after the drug was discontinued, resistance rates returned to the levels they had been when the study began.

"From clinical practice and during the recruitment phase of this study, we learned that many women are afraid of contracting drug-resistant bacteria using long-term antibiotic prophylaxis and preferred either no or nonantibiotic prophylaxis," the authors wrote in the Archives of Internal Medicine (2011; 171:1270-8). "In those women, cranberry prophylaxis may be a useful alternative despite its lower effectiveness."

Study authors received the cranberry and placebo capsules from Springfield Nutraceuticals BV, Oud Beijerland, the Netherlands.