Pharmacokinetic and Pharmacodynamic Effects of Metronidazole May Account for the Superior Efficacy of Multidose Therapy Among Women With Trichomoniasis

Diagnosis and Management of Trichomonas vaginalis: Summary of Evidence Reviewed for the 2021 Centers for Disease Control and Prevention Sexually Transmitted Infections Treatment Guidelines

Trichomonas vaginalis is likely the most prevalent nonviral sexually transmitted infection, affecting an estimated 3.7 million women and men in the United States. Health disparities are prominent in the epidemiology of trichomoniasis, as African Americans are >4 times more likely to be infected than persons of other races. Since publication of the 2015 Centers for Disease Control and Prevention sexually transmitted diseases treatment guidelines, additional data have bolstered the importance of T. vaginalis infection sequelae in women, including increased risk of human immunodeficiency virus (HIV) acquisition, cervical cancer, preterm birth, and other adverse pregnancy outcomes. Less is known about the clinical significance of infection in men. Newly available diagnostic methods, including point-of-care assays and multiple nucleic acid amplification tests, can be performed on a variety of genital specimens in women and men, including urine, allowing more accurate and convenient testing and screening of those at risk for infection. Repeat and persistent infections are common in women; thus, rescreening at 3 months after treatment is recommended. In vitro antibiotic resistance to 5-nitroimidazole in T. vaginalis remains low (4.3%) but should be monitored. High rates of T. vaginalis among sexual partners of infected persons suggest a role for expedited partner treatment. A randomized controlled trial in HIV-uninfected women demonstrated that multidose metronidazole 500 mg twice daily for 7 days reduced the proportion of women with Trichomonas infection at 1 month test of cure compared with women receiving single-dose therapy (2 g). The 2-g single-dose oral metronidazole regimen remains the preferred treatment in men.

Updates in trichomonas treatment including persistent infection and 5-nitroimidazole hypersensitivity

PURPOSE OF REVIEW

The purpose of this review is to update information on treatment of Trichomonas vaginalis. T. vaginalis is estimated to be the most common treatable sexually transmitted infection. In the world and is associated with poor birth outcomes, cervical cancer, sperm motility and morphology issues, and HIV acquisition and transmission.

RECENT FINDINGS

The efficacy of the recommended 2-g oral single-dose metronidazole (MTZ) for the treatment of T. vaginalis in women has recently been challenged. Two recent multicentered randomized trials and a meta-analysis have demonstrated that the 7-day dose of MTZ 500 mg twice daily was nearly two times more efficacious at clearing infection compared with the 2-g dose. Partner treatment is also essential, since up to 70% of male sexual partners can be infected and rescreening of treated women at 3 months is also recommended given the high repeat infection rates. Future studies should examine the importance of treating asymptomatic T. vaginalis, best treatment for men, the influence of the microbiome on treatment efficacy and different formulations of intravaginal treatments for hypersensitivity.

SUMMARY

7-day 500 mg twice daily MTZ should be used as the first line treatment for T. vaginalis-infected women.