Results from an open-label, randomized controlled trial showed that a 7-day dose of metronidazole is superior to a single dose of metronidazole for the treatment of trichomoniasis in women and should be the recommended preferred therapy, researchers reported in The Lancet Infectious Diseases.
Trichomoniasis is a widespread sexually transmitted infection (STI) — the most common nonviral STI in the world — with an estimated prevalence similar to syphilis, gonorrhea and chlamydia combined, although it is not a reportable disease, according to Patricia Kissinger, PhD, MPH, professor in the department of epidemiology at Tulane University’s School of Public Health and Tropical Medicine, and colleagues. Internationally, an estimated 143 million cases occur annually among women aged 15 to 29 years, they said.
Currently, the CDC and WHO recommend a single 2-g dose of oral metronidazole or tinidazole as first-line treatment and a 7-day regimen of two daily 400-mg or 500-mg doses of oral metronidazole as second-line treatment for Trichomonas vaginalis infection, but evidence has shown that one dose might not be enough, Kissinger and colleagues said.
They enrolled woman with T. vaginalis infection at three sexual health clinics in the United States from Oct. 6, 2014, to April 26, 2017, and randomly assigned them to receive single dose of 2 g of metronidazole or 500 mg of metronidazole twice daily for 7 days. According to the study, the primary outcome was T. vaginalis-positive result at the test-of-cure visit 4 weeks after completion of treatment.
In all, 311 participants were assigned to the singe-dose treatment group and 312 to the 7-day-dose group. At test of cure, a positive T. vaginalis screening occurred in 11% (n = 34) of patients in the 7-day-dose group compared with 19% (n = 58) in the single-dose group for a relative risk of .55 (95% CI, 0.34-0.70; P < .0001).
“The high rates of positive T. vaginalis results at TOC in both treatment groups are of concern,” Kissinger and colleagues wrote. “These findings suggest that the CDC recommendation to rescreen women treated for trichomoniasis should be upheld even for those women that receive the 7-day dose.”
In contrast to previous findings in patients with HIV, Kissinger and colleagues said they observed no treatment differences according to patient bacterial vaginosis status (P = .17) — a secondary outcome of the study.
“The reason for this result is not entirely clear,” they wrote. “One possible explanation of this result is that host factors affected treatment efficacy; HIV status seems to affect the vaginal microbiota with and without presence of bacterial vaginosis. Future studies should examine how the vaginal microbiota affects the treatment of trichomoniasis.”
According to the findings, side effects were similar by group, with nausea being the most at 23% (n = 124). Self-reported adherence was 96% in the 7-day-dose group compared with 99% in the single-dose group, Kissinger and colleagues reported.
“This study provides strong evidence that 7-day-dose metronidazole is a better treatment option for women with trichomoniasis than single-dose metronidazole, and recommendations should be adapted accordingly,” Kissinger and colleagues wrote. – by Marley Ghizzone
Disclosures: Kissinger reports receiving a portion of her salary from the National Institutes of Health/National Institute of Allergy and Infectious Diseases (1R01AI097080–01A1), via their institutions. Please see the study for all other authors’ relevant financial disclosures.