Urinary tract infections are pretty common in older women, but nobody knows the best way to treat them—which antibiotics, and for how long. Researchers in Quebec found that with antibiotics—as with jewelry—less can be more.

What the researchers wanted to know: Is three days or seven days of the antibiotic ciprofloxacin better for treating urinary treatment infections in older women?

What they did: Women 65 and older with urinary tract infections took either three days of antibiotics and four days of placebo or seven days of antibiotics. Neither the women nor the people who gave them the drugs knew whether they were getting all drugs or some placebo.

What they found: Two days after finishing the drugs, more than 90 percent of the women in both the three-day and the seven-day group had no bacteria in their urine and felt better. But more women in the seven-day group had the unpleasant side effects of ciprofloxacin, including nausea, drowsiness, and appetite loss.

What it means to you: Since there was no significant difference between women who took antibiotics for three days or seven days, except that more seven-day women had side effects, taking the drugs for three days sure seems like a better idea.

Caveats: The study didn't compare ciprofloxacin to other antibiotics. And the women in this study were pretty healthy, so the results don't necessarily apply to frail elderly women.

Find out more: Ciprofloxacin is part of the antibiotic class known as fluoroquinolones http://www.nlm.nih.gov/

National Kidney and Urologic Diseases Information Clearinghouse: http://kidney.niddk.nih.gov

Read the article: Vogel, T. et al. "Optimal Duration of Antibiotic Therapy for Uncomplicated Urinary Tract Infection in Older Women: a Double-blind Randomized Controlled Trial." Canadian Medical Association Journal. Feb. 17, 2004, Vol. 170, No. 4, pp. 469–473.

Abstract online: http://www.cmaj.ca/cgi/