New Orleans—Treatment of a common sexually transmitted disease (STD) might change after a new clinical trial found that current therapy is often inadequate.

An article in Lancet Infectious Diseases determined that the recommended single dose of medication isn’t enough to eliminate trichomoniasis, the most common curable STD. The infection can cause serious birth complications and make patients more susceptible to HIV, according to background information in the study.

For more than 30 years, the standard treatment for trichomoniasis, which affects about 143 million women globally each year, has been a single dose of the antibiotics metronidazole or tinidazole.

Tulane University–led researchers recruited more than 600 women for the randomized trial in New Orleans; Jackson, MI; and Birmingham, AL, which was conducted from October 6, 2014, to April 26, 2017. Participants were randomly assigned (1:1) to receive either a single dose of 2 g of metronidazole (single-dose group) or 500 mg of metronidazole twice daily for 7 days (7-day-dose group). The study was stopped early because of funding limitations.

Results indicate that patients in the 7-day-dose group were less likely to be T-vaginalis positive at test-of-cure than those in the single-dose group (34 [11%] of 312 vs. 58 [19%] of 311, relative risk 0·55, 95% CI 0·34–0·70; P <.0001).

Researchers note that side effects were similar between the groups, with the most common being nausea, 23%, followed by headache, 7%, and vomiting, 4%.

“The 7-day-dose metronidazole should be the preferred treatment for trichomoniasis among women,” the study concludes.

“There about 3.7 million new cases of trichomoniasis each year in the United States,” explained lead author Patricia Kissinger, PhD, MPH, an infectious disease epidemiologist at Tulane University School of Public Health and Tropical Medicine. “That means a lot of women have not been getting inadequate treatment for many decades.”

Trichomoniasis, which can increase the risk of contracting or spreading HIV, also can cause preterm delivery in pregnant women. In addition, babies born to infected mothers are more likely to have low birth weight.

Kissinger said she hopes the CDC will change its treatment recommendations because of the results of the study.

“We need evidence-based interventions to improve health,” Kissinger emphasized. “We can no longer do something because it’s what we’ve always done. I hope that this study will help to change the recommendations so that women can get the proper treatment for this common curable STD.”

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