Boric acid addition to suppressive antimicrobial therapy for recurrent bacterial vaginosis

Recurrent bacterial vaginosis (RBV) is extremely common and a source of frustration to patient and practitioners alike. In the absence of curative therapy, practitioners resort to retreating each individual episode. It has been suggested that vaginal biofilm in BV facilitates persistence of bacterial pathogens. Accordingly, topical boric acid (BA) aimed at biofilm removal was added to nitroimidazole induction and maintenance therapy creating a triple phase regimen to reduce symptomatic recurrence of BV in high-risk patients.

Uncontrolled, nonrandomized, retrospective chart review of patients with RBV treated with 7 days of oral nitroimidazole; followed by 21 days of intravaginal BA 600 mg/day and if in remission treated with metronidazole gel twice weekly for 16 weeks. Outcome was determined using Amsel criteria.

Fifty-eight women were treated for a total of 77 episodes of RBV. Sixty episodes of BV were available for a follow-up evaluation 4 to 12 weeks after enrollment, having completed both nitroimidazole and BA therapy and before initiating vaginal metronidazole gel. Cure after nitroimidazole and BA therapy ranged from 88% to 92%, 7 and 12 weeks after the initial visit, respectively. Cumulative cure at 12, 16, and 28 weeks from initial visit was 87%, 78%, and 65%, respectively. A failure rate of 50% was documented by 36 weeks of follow-up. No adverse effects of BA were observed.

Clinical experience with a triple phase maintenance regimen for women with RBV was encouraging but requires validation in a prospective randomized controlled study.