Boric Acid for the Treatment of Vaginitis: New Possibilities Using an Old Anti‐Infective Agent: A Systematic Review

Abstract

Introduction. Increasing microbial resistance to conventional pharmaceuticals calls for nonpharmaceutical treatments of vaginitis. This systematic review summarizes the efficacy of the antiseptic agent boric acid (BA) as a treatment option for microbial vaginitis in comparison to conventional therapies and proposes clinical recommendations. Materials and Methods. PubMed and Embase were searched for “boric acid” and “microbial vaginitis.” A protocol was registered on PROSPERO (CRD42020160146). Inclusion criteria included clinical trials, observational and interventional studies, including case series/reports. Exclusion criteria included in vitro and animal studies, non‐English language, and no BA treatment outcome. Primary outcomes included microbial, clinical, and complete cure. Secondary outcomes included adverse events, relapse/reinfection rates, evidence levels, microorganisms, treatment regimens, and follow‐up time. Data were extracted to a predefined Excel sheet. Results. Of 195 identified unique articles, 54 were retrieved and 41 met our inclusion criteria. Heterogeneity precluded the conduction of a meta‐analysis. Conclusion. An average cure rate of 76% was found for vulvovaginal candidiasis BA treatment. Recurrent bacterial vaginosis was controlled with BA and 5‐nitroimidazole with promising results. Maintenance BA was equal to maintenance oral itraconazole therapy in vulvovaginal candidiasis and bacterial vaginosis in a retrospective study. Prolonged BA monotherapy cured three of six recurrent Trichomonas infections. Adverse events (7.3%) were typically mild and temporary. Based on our findings and the rising antimicrobial therapy resistance, we suggest intravaginal BA 600 mg/day for 2 weeks for (recurrent) vulvovaginal candidiasis and 600 mg/day for 2‐3 weeks for recurrent bacterial vaginosis. Rare resistant Trichomonas infections can be treated with BA 600 mg × 2/day for months and in combination with oral antimicrobials. We suggest a maintenance regimen of BA 600 mg × 2/week for recurrent vulvovaginal candidiasis. In case of resistant bacterial vaginosis, we suggest BA 600 mg × 2‐3/week. Data on maintenance therapy and BA treatment of bacterial vaginosis and trichomoniasis are however limited.