C. diff Risk


Oral Bioavailability


Approximate Cost

Spectrum Of Activity


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

Standard Dose
500mg IV/PO q12h

Central nervous system and Clostridium difficile infections
500mg PO/IV q8h

No adjustment required

General Information

Common Usage

Suspected or confirmed anaerobic infections including:

  •  Intra-abdominal

  •  Biliary

  •  Central nervous system

  •  Clostridium difficile

  •  Giardia

  •  Pelvic infections

Also used in:

  •  Crohn's disease

  •  Bacterial vaginosis

Drug Monitoring

Assess for peripheral/optic neuropathy with prolonged therapy (>6wks) or if symptoms develop.

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 amoebic DNA is fragmented by reactive nitroso-imidazole radicals.


Antimicrobial class: Nitroimidazole

Pregnancy category: B

Average serum half life: 10 hours

Biliary penetration: Therapeutic

CSF penetration: Therapeutic

Lung penetration: Therapeutic

Urine penetration: Poor