C. diff Risk


Oral Bioavailability


Approximate Cost


PO: 500mg q12h

IV: 400mg IV q12h

For Severe Pseudomonas Infections:

PO: 750mg q12h

IV: 400mg q8h

General Information

Common Usage

Pseudomonas and other gram negative infections of urinary tract, bone/joint, abdomen, lung, and other sites

Drug Monitoring

Monitor QTc in patients with increased risk

Adverse Effects

  • QTc prolongation

  •  Dysglycemia

  •  CNS toxicity including confusion, psychosis

  • Tendinopathy and rupture

  • GI upset

  • Weakness exacerbation in myasthenia gravis

  • Rash

  • Retinal detachment

Major Interactions

  • CYP1A2 inhibitor - multiple interactions possible

  •  QTc prolongation - Increased risk with other agents that prolong QTc

  •  Di- & Trivalent cations including Al, Ca, Fe, Mg (antacids, dairy products, iron supplements, some enteral feeds) - decreased absorption

  •  Cyclosporine - increased levels of cyclosporine

  •  Warfarin - increased INR

  •  Decreases phenytoin levels

Additional Information

FDA Black Box warning against use in uncomplicated UTI, acute bacterial sinusitis, and acute exacerbation of chronic bronchitis where alternatives exist due to serious adverse side effects
May exacerbate muscle weakness in persons with myasthenia gravis. Avoid Use.


Antimicrobial class: Fluoroquinolone

Pregnancy category: C

Average serum half life: 4.0

Biliary penetration: Therapeutic

CSF penetration: Moderate

Lung penetration: Therapeutic

Urine penetration: Therapeutic