Week-Long Metronidazole Course Best for Trichomoniasis in Women

By Will Boggs MD

October 11, 2018

NEW YORK (Reuters Health) - A seven-day course of metronidazole provides better cure rates than a single dose in women with trichomoniasis, according to results from an open-label randomized controlled trial.

"Trichomonas vaginalis is an important sexually transmitted infection that requires appropriate treatment," Dr. Patricia Kissinger from Tulane University School of Public Health and Tropical Medicine, in New Orleans, told Reuters Health by email. "These data provide evidence that the 2-g single dose is inadequate and the 7-day dose treatment is needed."

The World Health Organization and the U.S. Centers for Disease Control and Prevention (CDC) recommend a single 2-g dose of oral metronidazole as first-line treatment and a seven-day dose of oral metronidazole (400 or 500 mg twice daily) as second-line treatment for trichomoniasis.

A recent meta-analysis, however, found that women treated for seven days had 46% fewer treatment failures than women who received a single dose.

Dr. Kissinger and colleagues at three U.S. clinics for sexually transmitted infections (STIs) evaluated the efficacy of a single versus a seven-day dose of metronidazole in 623 women with T. vaginalis infection and without HIV.

The study was stopped early because of funding limitations (the original intended sample size was 1,664 women).

Adherence to treatment was slightly but significantly lower in the seven-day-dose group (96%) than in the single-dose group (99%), the researchers reported in The Lancet Infectious Diseases, online October 5.

At the test-of-cure visit (mean, 4.9 weeks after completion of treatment), significantly fewer women in the seven-day-dose group (11%) than in the single-dose group (19%) tested positive for T. vaginalis.

Results were similar in the subgroup analysis of women with and without bacterial vaginosis.

Treatment-related side effects (most commonly nausea, headache, and vomiting) occurred with similar frequency in the two treatment groups.

"The findings of our prior study among HIV-infected women, the findings of our prior meta-analysis, and the present findings provide ample evidence that a 2-g dose of metronidazole is inadequate and the guidelines should be changed," Dr. Kissinger said.

"While adherence was good in this trial, in real life situations it may be an issue," she said. "Patients should be advised to take all the medicine as prescribed; taking it with non-dairy foods like crackers may help to reduce the chance of nausea. They should also be instructed to refrain from unprotected sex until a week after they and their partners have been treated."

"Women should seek care if they develop any symptoms and should be rescreened 3-4 months after treatment to determine if they have been re-infected," Dr. Kissinger said. "Screening is important, since as many as 70% of women with trichomoniasis have no symptoms."

She added, "From other studies we know that partners of women with trichomoniasis are likely to be infected. Partner treatment is, therefore, also needed."

Dr. Erin M. Keizur and Dr. Jeffrey D. Klausner of the University of California, Los Angeles, who wrote an accompanying editorial, told Reuters Health in a joint email, "Trichomoniasis should be treated for 7 total days, not just 1 day, to achieve a higher likelihood of cure for their patients. The guidelines must be updated so the primary recommended treatment for trichomoniasis in women is a 7-day course."

Like Dr. Kissinger, they highlighted "the importance of providing treatment for not only the infected patients, but their partners as well. Clinicians who don’t ensure that partners receive treatment are not practicing good medicine."

SOURCE: https://bit.ly/2C6BuId and https://bit.ly/2CyUYGw

Lancet Infect Dis 2018.