Conventional oral and secondary high dose vaginal metronidazole therapy for recurrent bacterial vaginosis: clinical outcomes, impacts of sex and menses

PURPOSE: Oral metronidazole therapy is the standard of care for bacterial vaginosis (BV), yet it has alarming rates of recurrence and refractory responses among recurrent BV (RBV) patients. This study addresses whether high dose vaginal metronidazole therapy (HDM) is beneficial in RBV patients who fail after standard of care (SOC) therapy, whether diagnostic test scores proximal to the HDM predict clinical outcome, and whether menses, coitus, or race influences therapy outcome. PATIENTS AND METHODS: A total of 90 patients with RBV were given SOC and tracked 74 for up to 9 months. Refractory or recurrent patients (57) with symptomatic BV were given HDM and followed for up to 8 months. Patients were evaluated by Amsel criteria, Nugent score, and a qPCR assay that assesses the Lactobacillus content. RESULTS: HDM achieved at least short-term remission in 68% of the patients who were refractory to or recurred after SOC and provided a 10-day increase in the mean duration of remission among patients who eventually recurred (p=0.027). Patients with prolonged dysbiosis (pH >5 or Amsel 4) before symptomatic recurrence were more likely to recur after subsequent HDM. Most recurrence happened within 10 days of menses, but sex in this cohort was not associated with clinical outcome. Mean diagnostic BV scores of African American patients in remission were inferior to scores of a small cohort of Caucasian patients in remission. CONCLUSION: Encouraging results obtained with HDM justify a prospective, randomized study to determine if follow-up HDM is beneficial among a broader cohort of women failing conventional oral metronidazole therapy.