Antibiotic Class:


Antimicrobial Spectrum:

Gram positive bacteria:  methicillin-susceptible Staphylococcus aureus (MSSA), methicillin-resistant Staphylococcus aureus (MRSA), Streptococcus pneumoniae, Listeria monocytogenes

Gram negative bacteria:  Enterobacteriaceae, H. influenzae, other Haemophilus spp., N. gonorrhoeae, N. meningitides, M. catarrhalis, Stenotrophomonas maltophilia, S. maltophilia

Mycobacteria:  Mycobacterium tuberculosis, M. fortuitum, M. kansasii, M. intracellulare, M. avium

Atypicals:  Legionella pneumophilia, Chlamydia pneumonia, Mycoplasma pneumoniae

Mechanism of Action:

Inhibition of topoisomerase (DNA gyrase) enzymes, which inhibits relaxation of supercoiled DNA and promotes breakage of double stranded DNA.


Fluoroquinolones produce both concentration-dependent (peak:MIC), and a combination of concentration and time-dependent killing (AUC:MIC).


400mg dose; Cmax: 4.5mg/L; Volume of distribution: 2.7L/kg; Table 2

Adverse Effects:

Gastrointestinal: nausea, upper GI discomfort

CNS:  headache, insomnia, dizziness; hallucinations, depression, psychotic reactions (rare)

Renal:  Interstitial nephritis

Cardiovascular:  QTC prolongation, torsades de pointes, arrhythmias


Oral: 400mg tablet

Intravenous: 400mg/250ml IV

Opthalmic: 0.5% solution


Chronic bronchitis: 400 mg PO/IV every 24 hr x 5 days

Community-acquired pneumonia: 400 mg PO/IV every 24 hr x 7-14 days

Conjunctivitis, bacterial: (0.5% ophthalmic solution) 1 drop to affected eye(s) 3 times a day x 7 days

Sinusitis: 400 mg IV or ORALLY every 24 hr for 10 days

Skin/skin structure infection: 400 mg PO/IV every 24 hr x 7 days


Efficacy and safety not established in patients less than 18 years of age

Table 4

Disease state based dosing:

Renal failure: No dosage adjustment recommended

Hepatic failure:  No dosing adjustment recommended

Dosing during Continuous Renal Replacement Therapy

CVVH (Continuous venovenous hemofiltration): 400mg q12h

CVVHD (Continuous venovenous hemodialysis): 400mg IV q12h

CVVHDF (Continuous venovenous hemodiafiltration) 400mg IV q12h

Note: CVVH is mainly for fluid removal alone. Many institutions will employ more CVVHD or CVVHDF which combine dialysis with fluid removal.



Drug Interactions:

Divalent cations:  aluminum, magnesium zinc, iron, calcium, antacids, sucralfate reduced bioavailability of quinolones (can cause therapeutic failure)


Category C: Risk unknown. Human studies inadequate.

Monitoring Requirements:

Therapeutic:  Culture and sensitivities, signs and symptoms of infection

Toxic:  Urinalysis, BUN, SCr, AST and ALT, Physicial examination: encephalopathic changes

Brand names/Manufacturer: