Metronidazole

C. diff Risk

None

Oral Bioavailability

Excellent

Approximate Cost

IV-$3/d PO-$1/d

Spectrum Of Activity

Dosing

500 mg PO/IV q12h

500 mg PO q8h for 10-14 days

There is a wide variety of dosage recommendations in the literature

15 mg/kg/dose IV/PO x 1 dose

Corrected gestational age less than or equal to 27 weeksCorrected gestational age 28 to 33 weeksCorrected gestational age 34 to 39 weeksCorrected gestational age 40 to 44 weeksBegin maintenance dose at appropriate dosing interval as outlined in table below (i.e. if loading dose is given at 0800 h, maintenance dose would be due at 1600 h if interval is q8h or 2000 h if interval is q12h, etc.).7.5 mg/kg/dose IV/PO q24h7.5 mg/kg/dose IV/PO q12h7.5 mg/kg/dose IV/PO q8h10 mg/kg/dose IV/PO q8h

Dosage adjustment in severe renal impairment only. Consult with a pharmacist for renal dosing

General Information

Common Usage

  • Suspected or confirmed anaerobic infections including intra-abdominal, biliary, central nervous system,

  • Clostridium difficile, Giardia and gynecoogical infections

  • Also used in Crohn's disease and bacterial vaginosis.

Drug Monitoring

With prolonged therapy (>6wks) or if symptoms develop assess for peripheral/optic neuropathy

Adverse Effects

  • GI symptoms common- especially nausea and vomiting and metallic taste

  • Peripheral and or optic neuropathy with extended therapy

  • Disulfiram-like reaction (severe vomiting)

  • Rare neurotoxicity including aseptic meningitis and encephalopathy

Major Interactions

Disulfiram reaction wtih alcohol or alcohol-containing medications/products.

Oral Liquids

Concentration: 50 mg/mL (compounded)
Taste: less palatable, unpleasant taste
Not all strengths of oral liquids are listed nor are available on IWK formulary

Tablet/Capsule Strengths

250 mg tablet
Tablets and capsules are preferred especially over an unpleasant tasting liquid.
Not all strengths of oral tablets/capsules are listed and they are not all available on the IWK formulary.

Pharmacology

Antimicrobial class: Nitroimidazole

Average serum half life:

  • Neonates <7 days: (prolonged with lower GA) 24.8-75.3 hours.

  • Neonates ≥7 days: ~22.5 hours

  • Children and adolescents: 6-10 hours.

  • Adults: 8 hours

Route of Elimination:

  • urine (unchanged drug and metabolites: 60-80%; ~20% of total as unchanged drug)

  • feces (6-15%)