A multidose course of metronidazole may be more effective than a single dose when treating Trichomonas vaginalis in women with HIV receiving antiretroviral therapy, according to researchers from Tulane University.
“This study can’t establish causality as it lacks experimentation and it is possible that ART is a marker of some other biological factor that interferes with metronidazole treatment of T. vaginalis,” the researchers wrote in Clinical Infectious Diseases. “It is recommended that to further elucidate the interaction of ART and metronidazole that pharmacokinetic studies be conducted.”
The study included 270 women with HIV who had culture-confirmed T. vaginalis. The women provided information about their HIV medications and other factors associated with persistent T. vaginalis infections. The women were randomly assigned 2 g metronidazole as a single dose or 500 mg metronidazole twice daily for 7 days. The women completed a test of cure 6 to 12 days after completing treatment.
More than half of the women were taking ART at their first visit. Among those, 95% of those were taking a nucleoside reverse transcriptase inhibitor, 61% were taking a protease inhibitor and 36% were taking a non-nucleoside reverse transcriptase inhibitor. The RR of treatment failure was 2.63 (95% CI, 1.04-6.63) for women on ART compared with women who were not. The researchers examined each treatment arm and found that this association was only among women receiving the single-dose treatment.
“Our study results show that ART is likely to interact with metronidazole for the treatment of T. vaginalis,” the researchers wrote. “This interaction occurs in the single 2-g dose and may occur in the multidose; however, the sample size was insufficient to detect interaction.”
Disclosure: The researchers report no relevant financial disclosures.