Efficacy study of suppressive vaginal metronidazole in reducing recurrent symptomatic episodes of bacterial vaginosis.

Multicenter prospective study with initial 10-day open-label metronidazole gel in which asymptomatic responders randomly assigned to receive twice weekly metronidazole vaginal gel or placebo for 16 weeks and off therapy for 12 weeks.

Of 157 eligible women with recurrent bacterial vaginosis, 112 of 127 returning evaluable women (88.2%) responded clinically and were randomly assigned. During suppressive therapy, recurrent bacterial vaginosis occurred in 13 women (25.5%) receiving metronidazole and 26 (59.1%) receiving placebo (MITT analysis, relative risk [RR] 0.43, CI = 0.25-0.73, P = .001). During the entire 28-week follow-up, recurrence occurred in 26 (51.0%) on treatment compared with 33 (75%) on placebo (RR 0.68, CI = 0.49-0.93, P = .02). Probability for remaining cured was 70% for metronidazole compared with 39% on placebo, which declined to 34% and 18%, respectively, by 28 weeks follow-up. Adverse effects were uncommon; however, secondary vaginal candidiasis occurred significantly more often in metronidazole-treated women (P = .02).

Suppressive therapy with twice-weekly metronidazole gel achieves a significant reduction in the recurrence rate of bacterial vaginosis; however, secondary vaginal candidiasis is common.