Objective: To assess the efficacy of 0.75% metronidazole vaginal gel, formulated at pH 4.0, for the treatment of bacterial vaginosis in a double-blind, placebo-controlled crossover trial.
Methods: Fifty-three women with bacterial vaginosis (clue cells of at least 20% plus vaginal pH of at least 4.7, amine odor, or homogeneous discharge) were enrolled. Women with concomitant infection by Candida, Trichomonas, Chlamydia trachomatis, or Neisseria gonorrhoeae were excluded. Five grams of metronidazole gel or placebo was inserted intravaginally twice daily for 5 days. Response to therapy was evaluated at 4-16 days and 1 month after treatment.
Results: Twenty-six of the 30 women (87%) who received metronidazole were free of bacterial vaginosis 9-21 days after enrollment, compared with only four (17%) of 23 placebo-treated women (P < .001). Women who were cured were followed prospectively. Those who had persistent bacterial vaginosis were crossed over to metronidazole gel in an open trial; bacterial vaginosis was eradicated in 21 of 23 (91%) of these women at the 2-week follow-up. Recurrent bacterial vaginosis developed within 1 month in four (15%) of 26 women who were initially cured after receiving metronidazole gel. Response to therapy was accompanied by a decrease in vaginal Bacteroides, Gardnerella vaginalis, and Mycoplasma hominis.
Conclusions: Treatment with intravaginal metronidazole gel resulted in a clinical cure in 87% (placebo-controlled trial) to 91% (crossover trial) of women with bacterial vaginosis. The recurrence rate of 15% at 1 month after treatment is similar to that reported with oral metronidazole.