MONTEREY, CALIF. — Four strategies that have been proposed to improve treatment of bacterial vaginosis produced mixed results, with only an extended course of metronidazole improving cure rates, and that only in the short term, Dr. Jane R. Schwebke reported.
A double-blind study randomized 568 women with bacterial vaginosis (BV) to one of four treatment arms: daily metronidazole for 7 days; metronidazole for 14 days; metronidazole for 7 days plus 1 g azithromycin on days 1 and 3, or metronidazole for 14 days plus azithromycin on days 1 and 3. The metronidazole was given in 750-mg extended-release form.
At a first follow-up visit 7 days after completion of treatment, BV was cured in 63% of patients who took metronidazole for 14 days, compared with 45% of patients who took metronidazole for 7 days.
By a second follow-up 21 days after completing treatment, however, there was no significant difference in cure rates among any groups.
Azithromycin therapy did not seem to make a difference at either time point, Dr. Schwebke and her associates reported in a poster presentation at the annual meeting of the Infectious Diseases Society for Obstetrics and Gynecology.
Any benefit from the longer course of metronidazole in the short term was lost in the long term. “We don't know if that's because of relapse of the problem or reinfection,” she said in an interview at the meeting.
Some physicians have advocated using 10–14 days of metronidazole to treat recurrent BV, although they lacked supportive data. Others have suggested that the relatively low cure rates of 50%–80% seen when treating BV with metronidazole or clindamycin may be due to resistant organisms that are susceptible to macrolide antibiotics, such as mycoplasmas and Mobiluncus curtisii, noted Dr. Schwebke, professor of medicine at the University of Alabama, Birmingham, and her associates.
Patients with a Nugent score at baseline of 5–8 (reflecting less complicated flora) were more likely to be cured than women with Nugent scores of 9–10, the intent-to-treat analysis found.
Other factors that have been shown in previous studies to affect cure rates also proved significant in this study. Consistent condom use, sexual abstinence, and refraining from douching improved chances of curing BV with treatment.