Top 300 Pharmacy Drug Cards

METRONIDAZOLE: Flagyl, Various

Class: Nitroimidazole Antibiotic

Dosage Forms. Capsule: 375 mg; SR Tablet: 750 mg; Tablet: 250 mg, 500 mg


Common FDA Label Indication, Dosing, and Titration.

1. Abscess, anaerobic: 7.5 mg/kg po q6h; max 4 g/d

2. Amebic dysentery, acute: Adults, 750 mg po tid × 5-10 d; Children, 35-50 mg/kg/d po in 3 divided doses for 10 d; max 750 mg/dose

3. Bacterial vaginosis: Extended-release tablets, 750 mg po daily × 7 d

4. Trichomoniasis: 2 g po × 1 d

Off-Label Uses.

1. Clostridium difficile diarrhea, including pseudomembranous colitis: (mild-moderate initial episode or first recurrence) 500 mg po tid × 10-14 d

2. Helicobacter pylori gastrointestinal tract infection: (Triple therapy) Metronidazole 500 mg po bid in combination with clarithromycin and a proton pump inhibitor

MOA. Metronidazole is a synthetic nitroimidazole active against Trichomonas vaginalis (trichomoniasis), Entamoeba histolytica (amebiasis), and Giardia lamblia (giardiasis); it is bactericidal against nearly all obligate anaerobic bacteria including Bacteroides fragilis.

Drug Characteristics: Metronidazole


Medication Safety Issues: Metronidazole


Drug Interactions: Metronidazole


Adverse Reactions: Metronidazole


Efficacy Monitoring Parameters. Resolution of clinical signs of infection (fever, cultures) within 2-3 d Toxicity Monitoring Parameters. Seek medical attention if severe diarrhea, dark urine, yellowing of skin or eyes, unusual bruising or bleeding, blistering skin rash, or shortness of breath.

Key Patient Counseling Points. Avoid alcohol while taking this medicine and for 3 d after, may cause severe disulfiram-like reaction. Complete full course of therapy. Symptoms should improve within 2-3 d; if they worsen, seek follow-up with healthcare practitioner.

Clinical Pearls. May resume normal activities after 24 h of antibiotics and afebrile. Drug of choice for mild-moderate C. difficile infection.

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