Metronidazole (Flagyl, MetroGel, MetroGel Vaginal)


  • Antibiotic


  • Antiprotozoal


  • Anaerobic infections

  • Trichomoniasis

  • Amebia

  • Colorectal surgery prophylaxis

  • Acne rosacea

  • Bacterial vaginosis


Trichomoniasis infections in the first trimester of pregnancy  


  • Pregnancy category B

  • Use with caution in patients with organic CNS disease or severe hepatic dysfunction

  • Use condoms during therapy to avoid re-infection if trichomoniasis

  • Counsel patient to finish all medication

  • Avoid using alcohol during therapy and 1-2 days post-therapy to avoid “disulfiram-type” reaction

  • Will cause a metallic taste in the mouth

  • Take with food to avoid GI side effects

  • Will darken the color of urine  

Adverse Reactions (Side Effects):

  • Seizures and peripheral neuropathy

  • Gastrointestinal: anorexia, nausea, diarrhea, cramping, metallic taste

  • Headache

  • Rash

  • Dysuria and darkened urine


  • Administered orally, topically and IV injection

  • Acute intestinal amebiasis:

    • 750mg tid for 5-10 days

  • Amebic liver abscess amebiasis:

    • Adult: 500-750mg tid for 5-10 days

    • Children: 35-50mg/kg/day in three divided doses for 10 days

  • Trichomoniasis (treat sexual partner(s) also):

    • One day therapy: 2 grams in one or two doses

    • Seven day therapy: 250mg tid for 7 days

  • Anaerobic bacterial infections:

    • Initial: 15mg/kg infused over one hour

    • Maintenance: Six hours post loading dose, 75mg/kg (max 4 grams per day) oral or IV (infused over 1 hour) q6h for 7-10 days

  • Colorectal surgery prophylaxis:

    • 15mg/kg infused IV (over 1 hour) and completed one hour prior to surgery, then 7.5mg/kg at 6 and 12 hour intervals after initial dose.

  • Acne rosacea:

    • Apply a thin film twice a day for 3-9 weeks

  • Bacterial vaginosis:

    • Insert 1 applicatorful (5 grams or 37.5mg metronidazole) once or twice a day for 5 days

    • For once daily dosing, dose at bedtime

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