Combined vaginal administration of nystatin, diiodohydroxyquin, and benzalkonium chloride versus oral metronidazole for the treatment of bacterial vaginosis

Objective To compare combined vaginal administration of nystatin, diiodohydroxyquin, and benzalkonium chloride versus oral metronidazole for the treatment of bacterial vaginosis (BV). Methods A randomized controlled trial was conducted among women diagnosed with BV using the Amsel criteria (n=90) at a university hospital in Khon Kaen, Thailand, between June 27, 2017, and April 30, 2018. The oral metronidazole group (n=44) received 400 mg of metronidazole, administered three times per day. The combined vaginal tablet group (n=46) received a vaginal suppository once daily, which comprised nystatin (100 000 U), diiodohydroxyquin (100 mg), and benzalkonium chloride (7 mg). Treatment was administered for 7 days in both groups. Follow‐up visits at 14 and 42 days assessed treatment outcomes and adverse effects. Results Remission of BV occurred among 41 (93%) women in the oral metronidazole group and 39 (85%) women in the combined vaginal tablet group. The adjusted relative risk was 0.92 (95% confidence interval 0.80–1.06). The rate of nausea and/or vomiting was significantly higher in the oral metronidazole group than that in the combined vaginal tablet group. Conclusion Treatment efficacy of the combined vaginal tablet versus oral metronidazole was equivalent. Clinical trial registration: TCTR20170627001 (www.clinicaltrials.in.th). Remission and recurrence rates were similar, but nausea and vomiting were lower, when using a combined vaginal tablet versus oral metronidazole to treat bacterial vaginosis.