For the treatment of vaginal bacterial infections, ovules containing the combination of metronidazole plus nystatin are significantly more effective than metronidazole gel, according to results of a trial conducted in Lima, Peru.

Bacterial vaginosis (BV) is a common condition caused by organisms with exotic names such as Gardnerella and Trichomonas. Symptoms include vaginal discharge and odor.

In Latin America, metronidazole plus the anti-fungal agent nystatin in intravaginal ovules, administered nightly for five to seven nights, is often prescribed for vaginal discharge - but the effectiveness of this treatment is unproven. This prompted Dr. Sixto Sanchez and colleagues to compare it to metronidazole once nightly for five nights, which is approved by the U.S. FDA.

Of 151 women with BV randomly assigned to one of the two treatments, 138 (91 percent) returned at least once for follow-up, the team notes in the American Journal of Obstetrics and Gynecology.

Rates of persistent or recurrent vaginosis at 14, 42, and 104 days were 20 percent, 38 percent, and 52 percent, respectively, after gel treatment; after ovule treatment the corresponding rates were significantly lower - 4 percent, 17 percent, and 33 percent.

The investigators think that the higher content of metronidazole in the ovules (500 milligrams) compared with the gel (37.5 mg per dose) might explain the better efficacy of this treatment, although additional studies are needed.

They also think the findings suggest that unprotected sex increases the risk of recurrence of vaginosis after initial improvement.

SOURCE: American Journal of Obstetrics and Gynecology, December 2004.