II. Mechanism

  1. Nitroimidazole antibiotic (includes tindazole, secnidazole)
  2. Inhibits Protein synthesis in susceptible organisms by disrupting DNA helix and resulting in DNA breakage

IV. Precautions

  1. Carcinogenic in mice and rats (FDA Black box warning)

V. Pharmacokinetics

  1. Half-Life: 8 hours
  2. Renal excretion

VI. Dosing: Children

  1. Dose
    1. Load: Metronidazole 15 mg/kg IV
    2. Maintenance: Metronidazole 7.5 mg/kg/dose
  2. Interval
    1. First week of life: q12 hours
    2. After first week of life: q 8hours

VII. Dosing: Adult

  1. Intravenous
    1. Loading dose: 15 mg/kg up to 1000 mg IV
    2. Maintenance dose: 7.5 mg/kg up to 500 mg IV q6-8 hour
  2. Oral dose: 250 to 750 mg PO tid

VIII. Adverse Effects

  1. Disulfiram Effect (Antabuse Effect)
    1. Since the 1960s, Alcohol has been strictly cautioned against when taking Metronidazole
    2. More recent data suggests no inhibition of aldehyde dehydrogenase as is seen with Disulfiram
    3. Safest to avoid Alcohol with Metronidazole, but interactions appear to be very uncommon
    4. (2021) Presc Lett 28(10): 58
  2. Gastrointestinal intolerance
  3. Neurotoxicity (stop immediately if these occur)
    1. Seizures
    2. Encephalopathy
    3. Cerebellar dysfunction
    4. Peripheral Neuropathy (e.g. distal Paresthesias)

IX. Pregnancy

  1. Class B Medication (Avoid in first trimester pregnancy)

X. Directions

  1. Taking with food decreases gastric irritation

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Related Studies

Cost: Medications

metronidazole (on 12/21/2022 at Medicaid.Gov Survey of pharmacy drug pricing)
METRONIDAZOLE 0.75% CREAM Generic $0.56 per gram
METRONIDAZOLE 0.75% LOTION Generic $1.90 per ml
METRONIDAZOLE 250 MG TABLET Generic $0.10 each
METRONIDAZOLE 500 MG TABLET Generic $0.14 each
METRONIDAZOLE TOP 1% GEL PUMP Generic $0.69 per gram
METRONIDAZOLE TOPICAL 0.75% GL Generic $0.46 per gram
METRONIDAZOLE TOPICAL 1% GEL Generic $1.06 per gram
METRONIDAZOLE VAGINAL 0.75% GL Generic $0.47 per gram