Once-daily use of a new extended release (ER) formulation of the antibiotic ciprofloxacin is as effective as twice-daily intermediate-release (IR) ciprofloxacin in clearing up urinary infection in women, according to researchers.

Ciprofloxacin ER (brand name Proquin XR, made by Depomed) “showed efficacy that was clearly at least as good as ciprofloxacin IR twice daily,” investigator Dr. Bret Berner told Reuters Health.

Dr. Berner, of Depomed Inc., Menlo Park, California, and colleagues note in the medical journal Antimicrobial Agents and Chemotherapy that by reducing the release rate of ciprofloxacin, the ER formulation may cause fewer stomach upsets and so patients may be more likely to stick with the treatment.

To investigate, the researchers studied 272 women with uncomplicated urinary infection who were assigned to take the ER formulation daily for three days. A further 257 women were given the IR formulation (CIPRO, Bayer) to take twice daily for three days.

Clinical cure rates at up to 11 days after treatment were 85.7 percent in the ER group and 86.1 percent in the IR group.

Both treatments were well tolerated but the frequency of nausea in the ER group (0.6 percent) was significantly lower than that in the IR patients (2.2 percent). This was also true of diarrhea (0.2 percent versus 1.2 percent).

“Ciprofloxacin ER has such a low incidence of nausea and diarrhea that is the only marketed fluoroquinolone where the label treats these as uncommon adverse events,” Berner commented.

SOURCE: Antimicrobial Agents and Chemotherapy, October 2005.