Armen Hareyan's picture

Trichomoniasis is caused by the protozoan T. vaginalis . Most men who are infected with T. vaginalis do not have symptoms; others have nongonococcal urethritis. Many infected women have symptoms characterized by a diffuse, malodorous, yellow-green discharge with vulvar irritation. However, some women have minimal or no symptoms. Diagnosis of vaginal trichomoniasis is usually performed by microscopy of vaginal secretions, but this method has a sensitivity of only about 60%--70%. Culture is the most sensitive commercially available method of diagnosis. No FDA-approved polymerase chain reaction test for T. vaginalis is available in the United States, but such testing may be available from commercial laboratories that have developed their own polymerase chain reaction tests.

Recommended Regimen

  • Metronidazole 2 g orally in a single dose.


Alternative Regimen

  • Metronidazole 500 mg twice a day for 7 days.

The nitroimidazoles comprise the only class of drugs useful for the oral or parenteral therapy of trichomoniasis. Of these, only metronidazole is readily available in the United States and approved by the FDA for the treatment of trichomoniasis. In randomized clinical trials, the recommended metronidazole regimens have resulted in cure rates of approximately 90%--95%; ensuring treatment of sex partners might increase this rate. Treatment of patients and sex partners results in relief of symptoms, microbiologic cure, and reduction of transmission. Metronidazole gel has been approved for treatment of BV. However, like other topically applied antimicrobials that are unlikely to achieve therapeutic levels in the urethra or perivaginal glands, it is considerably less efficacious for treatment of trichomoniasis ( < 50%) than oral preparations of metronidazole. Therefore, metronidazole gel is not recommended for use. Several other topically applied antimicrobials have occasionally been used for treatment of trichomoniasis, but it is unlikely that these preparations have greater efficacy than metronidazole gel.

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