Examining the Evidence
Q Can twice-weekly metronidazole keep recurrent BV in check?
<huc>A</huc> Yes. “Suppressive” antimicrobial therapy reduces the frequency of bacterial vaginosis (BV) in women with a history of recurrent infection. However, vulvovaginal candidiasis is a common side effect, and after suppressive therapy ends, most infections recur.
During the entire 28-week follow-up of this study, 26 women (51%) in the group receiving twice-weekly 0.75% metronidazole, 5 g intravaginally, had recurrent infection, compared with 33 women (75%) on placebo.
Not only is BV the most common vaginal infection in women of reproductive age, affecting 15% to 30% of nonpregnant women and roughly half of all gravidas, recurrence is a widespread problem: 33% of women have another infection within 3 months of treatment.
BV also can cause discomfort and serious reproductive tract complications, including postoperative upper genital tract infections and spontaneous preterm birth.
Until now, the usual approach to frequent recurrences of BV has been repeated short courses of treatment—often several per year. This is problematic because the drugs are expensive and “not entirely benign.”
BV diagnosis was rigorous
In this trial, BV was diagnosed using both clinical and microbiologic criteria. Clinical criteria for BV—better known as Amsel criteria—are the presence of at least 3 of the following: homogenous vaginal discharge, vaginal pH greater than 4.5, amine odor, and clue cells. The microbiologic definition of BV is based on Nugent criteria, which involves the assessment of a Gram-stained vaginal smear.
Antifungal may be needed
Women on suppressive therapy had a substantially increased frequency of vaginal candidiasis: 43.1% developed the infection, more than twice the frequency among controls. For this reason, physicians should be vigilant for candidiasis and consider suppressive therapy for it as well as BV.
Findings do not apply to gravidas
The findings of this study should not be extrapolated to a pregnant population.
Suppressive therapy is better than repeat courses
Although suppressive therapy did not eliminate recurrence, many women experienced major improvement. The increased frequency of candidiasis may warrant suppressive antifungal therapy.
In the “real world,” some providers base “diagnoses” on the symptoms reported rather than a rigorous physical exam. However, use of Amsel criteria is strongly encouraged, unless the lab is experienced in Nugent scoring of Gram-stained smears.