Metronidazole

C. diff Risk

Low

Oral Bioavailability

Excellent

Approximate Cost

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

Dosing

Adult

Standard Dose
500mg IV/PO q12h

Intra-abdominal, central nervous system and Clostridium difficile infections
500mg PO/IV q8h

Hepatic

Consider dose reduction with severe hepatic impairment (Child-Pugh C)

General Information

Common Usage

Suspected or confirmed anaerobic infections including:

  •  Intra-abdominal

  •  Biliary

  •  Central nervous system

  •  Clostridium difficile

  •  Giardia

  •  Pelvic infections

Also used in:

  •  Crohns disease

  •  Bacterial vaginosis

  •  Hepatic encephalopathy

Drug Monitoring

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

Adverse Effects

GI symptoms common- especially nausea/vomiting and metallic taste.

Peripheral/optic neuropathy with extended therapy.

Disulfiram-like reaction (severe vomiting).

Rare neurotoxicity including aseptic meningitis and encephalopathy.

Major Interactions

Ethanol - Disulfiram-like reaction

Increases levels of:

  •  Cyclosporine

  •  Lithium

  •  Warfarin

  •  Phenobarbital

  •  Phenytoin

Additional Information

Bacterial, protozoal and ameobic DNA is fragmented by reactive nitroso-imidazole radicals

Pharmacology

Antimicrobial class: Nitroimidazole

Pregnancy category: B

Average serum half life: 10.0

Biliary penetration: Therapeutic

CSF penetration: Therapeutic

Lung penetration: Therapeutic

Urine penetration: Poor