THE MINIMUM SINGLE ORAL METRONIDAZOLE DOSE FOR TREATING TRICHOMONIASIS - A RANDOMIZED, BLINDED STUDY

Objective: To identify the minimum effective single oral dose of metro nidazole for trichomoniasis. Methods: Women attending an inner-city se xually transmitted disease clinic who had Trichomonas vaginalis vagini tis diagnosed by microscopy were recruited for this randomized, double -blind study. Subjects were given a 0.5-, 1-, 1.5-, or 2-g single oral dose of metronidazole, taken under direct observation. Demographic in formation, symptoms, and clinical findings were collected from patient interviews, and physical examinations were conducted at the time of e nrollment and at the follow-up visit. The primary outcome measure was treatment success at the follow-up visit, established by negative cult ure and microscopy. Results: Three (1.8%) of the 167 women enrolled we re excluded because of vomiting after taking metronidazole, and 66 (40 %) of the 164 remaining subjects did not return for the follow-up visi t. No associations were found between the proportion of subjects lost to follow-up and the characteristics of these subjects across assignme nt groups. The treatment success ratio was highest in subjects who rec eived the 1.5-g dose (23, 85%), followed by the 2-g (16, 84%), 1-g (18 , 62%), and the 0.5-g dose (8, 35%). Conclusion: A single 1.5-g dose o f metronidazole has efficacy equivalent to a single 2-g dose for the t reatment of T vaginalis vaginitis. (C) 1997 by The American College of Obstetricians and Gynecologists.