ATLANTA — Single-dose oral metronidazole—one of two recommended first-line treatment regimens for Trichomonas vaginalis—is less effective than a second-line, 7-day regimen of oral metronidazole in HIV-positive women, results from a randomized trial suggest.
Among 255 patients evaluated 6-12 days after treatment, those who received metronidazole 500 mg twice daily for 7 days were about half as likely as those receiving a single 2-g dose of metronidazole to have recurrent T. vaginalis infections (9% vs. 17%), according to the findings of a phase IV trial of medications that were already approved for this intended use.
The 7-day regimen also was associated with a lower rate of T. vaginalis positivity among 152 women who were assessed 3 months after treatment, with rates of 11% and 24%, respectively, said Dr. Patricia Kissinger, professor of epidemiology at Tulane University in New Orleans.
There was no difference in adherence between groups, with almost all patients (96%) reporting haven taken all of their metronidazole as instructed, and there were no significant differences in adverse event rates between the two arms.
Based on these findings, metronidazole administered as a single 2-g dose should no longer be recommended for the treatment of T. vaginalis among HIV-positive women, Dr. Kissinger said at a conference on STD prevention sponsored by the Centers for Disease Control and Prevention.
The National Institutes of Health funded the study. Dr. Kissinger reported having no relevant conflicts of interest.